U.S. patent application number 10/645065 was filed with the patent office on 2004-05-06 for substrate processing apparatus and substrate processing method.
This patent application is currently assigned to Dainippon Screen Mfg. Co., Ltd.. Invention is credited to Araki, Hiroyuki, Hara, Takashi, Hiraoka, Nobuyasu, Okumura, Tsuyoshi, Yokouchi, Kenichi.
Application Number | 20040084144 10/645065 |
Document ID | / |
Family ID | 32180287 |
Filed Date | 2004-05-06 |
United States Patent
Application |
20040084144 |
Kind Code |
A1 |
Yokouchi, Kenichi ; et
al. |
May 6, 2004 |
Substrate processing apparatus and substrate processing method
Abstract
A substrate processing apparatus that removes an unwanted
material on a surface of a peripheral portion of a substrate
through etching by supplying etching liquid to the surface of the
peripheral portion. The apparatus includes an etching liquid
supplying mechanism that supplies the etching liquid to the
peripheral portion of the substrate, and an annular member that has
an inner periphery on or inside an outer periphery of the substrate
and thereby defines a processing width to be processed by the
etching liquid on the surface of the peripheral portion of the
substrate. The annular member may be placed in close proximity to
the surface of the peripheral portion of the substrate while
securing a certain gap such that allows the annular member to come
in contact with a liquid film of the etching liquid formed on the
surface of the peripheral portion.
Inventors: |
Yokouchi, Kenichi; (Kyoto,
JP) ; Hara, Takashi; (Kyoto, JP) ; Araki,
Hiroyuki; (Kyoto, JP) ; Hiraoka, Nobuyasu;
(Kyoto, JP) ; Okumura, Tsuyoshi; (Kyoto,
JP) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
|
Assignee: |
Dainippon Screen Mfg. Co.,
Ltd.
|
Family ID: |
32180287 |
Appl. No.: |
10/645065 |
Filed: |
August 21, 2003 |
Current U.S.
Class: |
156/345.11 |
Current CPC
Class: |
H01L 21/67051 20130101;
C03C 15/00 20130101 |
Class at
Publication: |
156/345.11 |
International
Class: |
C23F 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 21, 2002 |
JP |
2002-240891 |
Sep 27, 2002 |
JP |
2002-283458 |
Nov 28, 2002 |
JP |
2002-346179 |
Claims
What is claimed is:
1. A substrate processing apparatus that removes an unwanted
material on a surface of a peripheral portion of a substrate
through etching by supplying etching liquid to the surface of the
peripheral portion, the apparatus comprising: an etching liquid
supplying mechanism that supplies the etching liquid to the
peripheral portion of the substrate; and an annular member that has
an inner periphery on or inside an outer periphery of the substrate
and thereby defines a processing width to be processed by the
etching liquid on the surface of the peripheral portion of the
substrate.
2. The substrate processing apparatus according to claim 1,
wherein: the annular member is placed in close proximity to the
surface of the peripheral portion of the substrate while securing a
certain gap such that allows the annular member to come in contact
with a liquid film of the etching liquid formed on the surface of
the peripheral portion.
3. The substrate processing apparatus according to claim 1, further
comprising: a substrate holding mechanism that holds the substrate
from one surface side thereof, wherein the annular member is placed
on the other surface side of the substrate.
4. The substrate processing apparatus according to claim 1,
wherein: the etching liquid is supplied to the peripheral portion
of the substrate from the etching liquid supplying mechanism while
the substrate is held at rest.
5. The substrate processing apparatus according to claim 1,
wherein: the substrate is a substrate of a nearly circular shape;
the apparatus further comprises a substrate rotating mechanism that
rotates the substrate; and the inner periphery of the annular
member is of a circular shape having an inside diameter equal to or
smaller than a diameter of the substrate.
6. The substrate processing apparatus according to claim 5,
wherein: the etching liquid is supplied to the peripheral portion
of the substrate from the etching liquid supplying mechanism while
the substrate is rotated by the substrate rotating mechanism.
7. The substrate processing apparatus according to claim 1,
wherein: the annular member includes a substrate-opposing surface
that extends outwards from the inner periphery and opposes the
surface of the peripheral portion of the substrate.
8. The substrate processing apparatus according to claim 7,
wherein: the substrate-opposing surface is a plane nearly parallel
to the surface of the peripheral portion of the substrate.
9. The substrate processing apparatus according to claim 7,
wherein: the substrate-opposing surface is an inclined plane
inclined to reduce an interval between the substrate-opposing
surface and the substrate as heading toward the inner
periphery.
10. The substrate processing apparatus according to claim 7,
wherein: an outer periphery of the substrate-opposing surface is
located outside the outer periphery of the substrate.
11. The substrate processing apparatus according to claim 7,
wherein: the annular member includes a projection that protrudes
from the substrate-opposing surface toward the substrate and
thereby limits the etching liquid heading toward an inside of the
substrate.
12. The substrate processing apparatus according to claim 11,
wherein: the projection includes, on an outer side of the annular
member, an etching liquid limiting surface having an inclined plane
that heads toward an outside of the substrate as going away from a
surface of the substrate.
13. The substrate processing apparatus according to claim 7,
wherein: the annular member includes a liquid discharge path that
opens in the substrate-opposing surface and communicates with an
external space of the annular member.
14. The substrate processing apparatus according to claim 7,
wherein: the etching liquid supplying mechanism includes a liquid
dispense path made in the annular member and including a dispense
port that opens in the substrate-opposing surface.
15. The substrate processing apparatus according to claim 7,
wherein: the etching liquid supplying mechanism includes a dispense
port that opens in the substrate-opposing surface, a
liquid-receiving portion that communicates with the dispense port,
and a nozzle that supplies the liquid-receiving portion with the
etching liquid.
16. The substrate processing apparatus according to claim 15,
wherein: the annular member is placed so that the
substrate-opposing surface opposes the substrate from above; and
the liquid-receiving portion is formed in an upper surface of the
annular member.
17. The substrate processing apparatus according to claim 1,
wherein: the etching liquid supplying mechanism includes a nozzle
that supplies the etching liquid toward a surface of the substrate
on an opposite side to a surface containing the surface of the
peripheral portion.
18. The substrate processing apparatus according to claim 17,
wherein: the nozzle supplies the etching liquid toward a central
portion of the surface on the opposite side.
19. The substrate processing apparatus according to claim 1,
wherein: the annular member has an outer wall surface positioned
inside the outer periphery of the substrate.
20. The substrate processing apparatus according to claim 19,
wherein; the etching liquid supply mechanism includes a nozzle
provided outside the annular member.
21. The substrate processing apparatus according to claim 1,
wherein: the etching liquid supplying mechanism includes a nozzle
that supplies the etching liquid toward an outer wall surface of
the annular member.
22. The substrate processing apparatus according to claim 1,
wherein: the etching liquid supplying mechanism includes a dispense
port through which the etching liquid is dispensed in a direction
perpendicular to a surface of the substrate or a direction inclined
toward an outside of the substrate.
23. The substrate processing apparatus according to claim 1,
wherein: the annular member includes an inner wall surface that
rises from the inner periphery in a direction to go away from a
surface of the substrate.
24. The substrate processing apparatus according to claim 23,
wherein: the inner wall surface is an inclined plane that heads
toward a center of the substrate as going away from the surface of
the substrate.
25. The substrate processing apparatus according to claim 1,
further comprising: a lid member that substantially clogs an
internal space of the annular member.
26. The substrate processing apparatus according to claim 25,
wherein: the annular member includes an annular groove formed
adjacently inside the inner periphery.
27. The substrate processing apparatus according to claim 1,
further comprising: a gas supplying mechanism that supplies an
internal space .mu.l of the annular member with a gas.
28. The substrate processing apparatus according to claim 27,
wherein: the annular member includes an inner wall surface that
rises from the inner periphery in a direction to go away from a
surface of the substrate, and the gas supplied from the gas
supplying mechanism is supplied toward the inner wall surface.
29. The substrate processing apparatus according to claim 23,
wherein: the annular member includes a gas flowing path that allows
a communication between an internal space and an external space of
the annular member.
30. The substrate processing apparatus according to claim 1,
further comprising: a protection liquid supplying mechanism that
supplies etching protection liquid toward a center of the substrate
at an inner side of the annular member.
31. A substrate processing method of removing an unwanted material
on a surface of a peripheral portion of a substrate through etching
by supplying etching liquid to the surface of the peripheral
portion, the method comprising: a step of placing a mound of the
etching liquid on the surface of the peripheral portion of the
substrate while the substrate is held at rest; and a step of
placing an annular member, having an inner periphery on or inside
an outer periphery of the substrate, in close proximity to the
surface of the peripheral portion of the substrate and thereby
defining a processing width to be processed by the etching liquid
on the surface of the peripheral portion of the substrate.
32. The method according to claim 31, wherein: the annular member
placing step includes a step of placing the annular member while
securing a certain gap such that allows the annular member to come
in contact with a liquid film of the etching liquid formed on the
surface of the peripheral portion of the substrate.
33. The method according to claim 32, further comprising: a gas
supplying step of supplying an internal space of the annular member
with a gas.
34. The method according to claim 32, further comprising: a
protection liquid supplying step of supplying etching protection
liquid to a central region of the substrate at an inner side of the
annular member.
35. A substrate processing method of removing an unwanted material
on a surface of a peripheral portion of a substrate through etching
by supplying etching liquid to the surface of the peripheral
portion, the method comprising: a step of performing, in parallel,
(a) a substrate rotating step of rotating the substrate, and (b) an
etching liquid supplying step of supplying the etching liquid to
the surface of the peripheral portion of the substrate being
rotated; and a step of placing an annular member, having an inner
periphery on or inside an outer periphery of the substrate, in
close proximity to the surface of the peripheral portion of the
substrate and thereby defining a processing width to be processed
by the etching liquid on the surface of the peripheral portion of
the substrate.
36. The method according to claim 35, wherein: the annular member
placing step includes a step of placing the annular member while
securing a certain gap such that allows the annular member to come
in contact with a liquid film of the etching liquid formed on the
surface of the peripheral portion of the substrate.
37. The method according to claim 35, wherein: the etching liquid
supplying step includes a step of supplying the etching liquid
toward a surface of the substrate on an opposite side to a surface
containing the surface of the peripheral portion.
38. The method according to claim 35, further comprising: a gas
supplying step of supplying an internal space of the annular member
with a gas.
39. The method according to claim 35, further comprising: a
protection liquid supplying step of supplying etching protection
liquid to a central region of the substrate at an inner side of the
annular member.
40. A substrate processing apparatus that applies processing to a
peripheral portion of a substrate with the use of processing
liquid, the apparatus comprising: a substrate holding mechanism
that holds the substrate almost horizontally and rotates the
substrate about a nearly vertical rotational axis line; an opposing
member that includes a substrate-opposing surface opposing an upper
surface of the substrate held by the substrate holding mechanism
and having a hydrophobic property at least in a peripheral portion
region, and a hydrophilic upper surface inclined to near an end
edge of the substrate-opposing surface as heading downward, the
opposing member protecting a central portion of the upper surface
of the substrate by bringing the substrate-opposing surface in
close proximity to the upper surface of the substrate; and a
processing liquid supplying mechanism that supplies the processing
liquid to the upper surface of the opposing member.
41. The substrate processing apparatus according to claim 40,
wherein: the opposing member is formed in a shape of a rotational
body having an axis line nearly along the rotational axis line as a
central axis line.
42. The substrate processing apparatus according to claim 40,
wherein: the opposing member further includes a hydrophilic side
surface that connects the end edge of the substrate-opposing
surface and an end edge of the upper surface of the opposing
member.
43. The substrate processing apparatus according to claim 40,
further comprising: an inert gas supplying mechanism that supplies
an inert gas to a space between the upper surface of the substrate
held by the substrate holding mechanism and the substrate-opposing
surface.
44. A substrate processing apparatus that applies processing, with
the use of processing liquid, to a region to be processed including
at least part of a peripheral portion of a substrate, the apparatus
comprising: a substrate holding mechanism that holds the substrate;
an opposing member that includes a substrate-opposing surface
opposing an upper surface of the substrate held by the substrate
holding mechanism and having an end edge corresponding to a
boundary set on the upper surface of the substrate to divide the
region to be processed and a region not to be processed as well as
having a hydrophobic property at least in a peripheral portion
region, and an hydrophilic upper surface inclined to near the end
edge of the substrate-opposing surface as heading downward, the
opposing member protecting the region not to be processed on the
upper surface of the substrate by brining the substrate-opposing
surface in close proximity to the upper surface of the substrate;
and a processing liquid supplying mechanism that supplies the
processing liquid to the upper surface of the opposing member.
45. The substrate processing apparatus according to claim 44,
wherein: the opposing member further includes a hydrophilic side
surface that connects the end edge of the substrate-opposing
surface and an end edge of the upper surface of the opposing
member.
46. The substrate processing apparatus according to claim 44,
further comprising: an inert gas supplying mechanism that supplies
an inert gas to a space between the upper surface of the substrate
held by the substrate holding mechanism and the substrate-opposing
surface.
47. A method of applying processing to a peripheral portion of a
substrate with the use of processing liquid, the method comprising:
a substrate rotating and holding step of rotating the substrate
about a nearly vertical rotational axis line in an almost
horizontal posture by a substrate holding mechanism; an opposing
member approximating step of bringing an opposing member, in close
proximity to the upper surface of the substrate held by the
substrate holding mechanism, the opposing member being provided
with a substrate-opposing surface opposing an upper surface of the
substrate held by the substrate holding mechanism and having a
hydrophobic property at least in a peripheral portion region and a
hydrophilic upper surface inclined to near an end edge of the
substrate-opposing surface as heading downward; and a processing
liquid supplying step of supplying the processing liquid to the
upper surface of the opposing member in allowing the processing
liquid to flow down to the peripheral portion of the substrate held
by the substrate holding mechanism from the end edge of the
substrate-opposing surface.
48. A method of applying processing to a region to be processed of
a substrate with the use of processing liquid, the method
comprising: a substrate holding step of having a substrate holding
mechanism hold the substrate almost horizontally; an opposing
member approximating step of bringing an opposing member, in close
proximity to the upper surface of the substrate held by the
substrate holding mechanism, the opposing member being provided
with a substrate-opposing surface opposing an upper surface of the
substrate held by the substrate holding mechanism and having an end
edge corresponding to a boundary set on the upper surface of the
substrate to divide the region to be processed and a region not to
be processed as well as having a hydrophobic property at least in a
peripheral portion region and a hydrophilic upper surface inclined
to near the end edge of the substrate-opposing surface as heading
downward; and a processing liquid supplying step of supplying the
processing liquid to the upper surface of the opposing member in
allowing the processing liquid to flow down to the region to be
processed of the substrate held by the substrate holding mechanism
from the end edge of the substrate-opposing surface.
49. A substrate processing apparatus that applies processing to a
peripheral portion of a substrate with the use of processing
liquid, the apparatus comprising: a substrate holding mechanism
that holds the substrate almost horizontally and rotates the
substrate about a nearly vertical rotational axis line; an opposing
member placed oppositely to an upper surface of the substrate held
by the substrate holding mechanism and including a projection strip
protruding toward the substrate at an edge portion; and a
processing liquid supplying mechanism that supplies the opposing
member with the processing liquid.
50. The substrate processing apparatus according to claim 49,
wherein: the opposing member includes a substrate-opposing surface
having the projection strip protruding toward the substrate at an
edge portion, and an upper surface connected to the projection
strip; and the processing liquid supplying mechanism supplies the
processing liquid to the upper surface of the opposing member.
51. The substrate processing apparatus according to claim 50,
wherein: the upper surface of the opposing member is inclined to
near a periphery of the substrate held by the substrate holding
mechanism as heading downward.
52. The substrate processing apparatus according to claim 50,
wherein: the upper surface of the opposing member has a hydrophilic
property.
53. The substrate processing apparatus according to claim 49,
wherein: the projection strip of the opposing member has a lower
end edge located above the peripheral portion of the substrate held
by the substrate holding mechanism.
54. The substrate processing apparatus according to claim 49,
wherein: the projection strip of the opposing member includes, in a
lower surface, a plane nearly parallel to the upper surface of the
substrate held by the substrate holding mechanism.
55. The substrate processing apparatus according to claim 49,
wherein: the projection strip of the opposing member includes, in a
lower surface, an inclined plane that nears the upper surface of
the substrate held by the substrate holding mechanism as
approaching the rotational axis line.
56. The substrate processing apparatus according to claim 49,
wherein: the projection strip of the opposing member includes, in a
lower surface, a hydrophilic surface opposing the upper surface of
the substrate held by the substrate holding mechanism.
57. The substrate processing apparatus according to claim 49,
further comprising: an opposing member rotating mechanism that
rotates the opposing member about the rotational axis line.
58. The substrate processing apparatus according to claim 57,
wherein: the opposing member rotating mechanism rotates the
opposing member at a rotational speed lower than a rotational speed
at which the substrate is rotated by the substrate holding
mechanism.
59. A method of applying processing to a peripheral portion of a
substrate with the use of processing liquid, the method comprising:
a substrate rotating step of having a substrate holding mechanism
hold the substrate almost horizontally and rotating the substrate
about a nearly vertical rotational axis line; an opposing member
approximating step of bringing an opposing member, in close
proximity to the substrate held by the substrate holding mechanism,
the opposing member being placed oppositely to an upper surface of
the substrate held by the substrate holding mechanism and including
a projection strip protruding toward the substrate at an edge
portion; and a processing liquid supplying step of supplying the
processing liquid to the opposing member in allowing the processing
liquid to flow down to the peripheral portion of the substrate held
by the substrate holding mechanism from the projection strip.
60. The method according to claim 59, wherein: the opposing member
includes a substrate-opposing surface having the projection strip
protruding toward the substrate at an edge portion and an upper
surface connected to the projection strip; and the processing
liquid supplying step includes a step of supplying the processing
liquid to the upper surface of the opposing member.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a substrate processing apparatus
and a substrate processing method for applying processing to a
surface (in particular, a peripheral portion) of a substrate.
Substrates subject to processing include various kinds of
substrates, such as a semiconductor wafer, a glass substrate for a
liquid crystal display, a glass substrate for a plasma display
panel, a substrate for an optical disc, a substrate for a magnetic
disc, a substrate for a magneto-optical disc, and a substrate for a
photomask.
[0003] 2. Description of Related Art
[0004] The fabrication sequence of a semiconductor device
occasionally includes processing that removes, through etching, an
unwanted portion of a metal thin film, such as a copper thin film,
formed across the entire main surface and peripheral end surface
(and the back surface when needed) of a semiconductor wafer
(hereinafter, referred to simply as the wafer). For example,
because it is sufficient to provide a copper thin film used to form
wirings to an element-forming region on the surface of the wafer
alone, the copper thin film formed on the peripheral portion of the
surface (for example, a portion approximately 5 mm wide from the
peripheral edge of the wafer), the back surface, and the peripheral
end surface of the wafer is unnecessary. Moreover, copper or copper
ions on the peripheral portion, the back surface, and the
peripheral end surface raise a problem that they contaminate the
hands of a substrate-transporting robot provided to a substrate
processing apparatus, and such contamination is transferred to
another substrate held by the contaminated hands.
[0005] Another processing is performed occasionally for the similar
reason, by which metal contaminants (including metal ions) on the
surfaces of films (silicon dioxide film, nitride film, etc.) other
than the metal film formed on the substrate periphery are removed
by slightly etching away these films.
[0006] A substrate periphery processing apparatus used to
selectively etch away the thin film on the peripheral portion and
the peripheral end portion of the wafer includes, for example, a
spin chuck that rotates while holding a wafer horizontally, a
blocking plate that limits a space on the wafer above the spin
chuck, and an etching liquid supply nozzle that supplies etching
liquid to the lower surface of the wafer. The etching liquid
supplied to the lower surface of the wafer is forced outwards in
the direction of the turning radius on the lower surface of the
wafer by a centrifugal force, comes around the end surface of the
wafer to the upper surface of the wafer, and thereby etches away
unwanted materials on the peripheral portion of the upper surface
of the wafer. In this instance, the blocking plate is placed in
close proximity to the upper surface of the wafer, and an inert
gas, such as a nitrogen gas, is supplied to a space between the
blocking plate and the wafer.
[0007] Because a quantity of the etching liquid coming around to
the upper surface can be adjusted by adequately adjusting a flow
rate of the inert gas and the rotational speed of the spin chuck,
etching processing can be applied selectively to a region of a
specific width (for example, 1 to 7 mm wide) in the peripheral
portion of the upper surface of the wafer (so-called bevel etching
processing).
[0008] By supplying the etching liquid to the wafer from the lower
surface while the wafer is held and rotated by the spin chuck,
unwanted materials on the peripheral portion of the upper surface
of the wafer is removed through etching. Subsequently, deionized
water rinsing processing is applied to both the upper and lower
surfaces of the wafer followed by drying processing, by which the
spin chuck is rotated at a high speed to throw off water droplets
on the upper and lower surfaces.
[0009] According to the arrangement as described above, however, a
quantity of the etching liquid coming around to the upper surface
cannot be controlled precisely, which raises a problem that
accuracy as to an etching width becomes so poor that the etching
width varies in all parts along the peripheral portion of the
wafer.
[0010] To be more specific, when there is a considerable distance
between the upper surface of the wafer and the blocking plate, the
etching liquid does not come in contact with the blocking plate.
Thus, a quantity of the etching liquid coming around to the upper
surface of the wafer is too small to control precisely a quantity
of the etching liquid coming around to the upper surface. Further,
in this case, there is another problem that a communication space
connecting a space between the upper surface of the wafer and the
blocking plate to an external space is large enough to allow an
atmosphere, scattered droplets, or a fog or vapor (so-called mist)
of the etching liquid to enter a device-forming region at the
central portion of the surface of the wafer from outside.
[0011] On the other hand, when there is a short distance between
the upper surface of the wafer and the blocking plate, the etching
liquid having come around to the upper surface of the wafer comes
in contact with the lower surface (plane) of the blocking plate.
Thus, a quantity of the etching liquid coming around to the upper
surface is too large to control precisely a quantity of the etching
liquid coming around to the upper surface.
[0012] As has been discussed, a quantity of the etching liquid
coming around to the upper surface cannot be controlled precisely
in either case.
[0013] Further, for example, when there is a difference between the
rotational speed of the wafer and the rotational speed of the
blocking plate, an airflow between the wafer and the blocking plate
is disturbed, which may possibly vary a quantity of the etching
liquid coming around to the upper surface of the wafer.
[0014] Also, in the case of a substrate processing apparatus
according to another related art, as is disclosed in Japanese
Laid-open Patent Application No. 2002-75953, a wafer is rotated
while being held almost horizontally, and in the mean time, the
blocking plate is placed oppositely at a position in close
proximity to the upper surface (device-forming surface) of the
wafer. Then, the blocking plate is rotated about the rotational
axis line of the wafer while the etching liquid is supplied to the
upper surface of the blocking plate. The etching liquid is then
forced to scatter diagonally downward from the periphery of the
blocking plate by a centrifugal force induced by rotations of the
blocking plate, and the etching liquid is thereby supplied to the
peripheral portion of the upper surface of the wafer. The etching
liquid supplied to the peripheral portion of the upper surface of
the wafer is then forced to flow toward the periphery of the wafer
by a centrifugal force induced by rotations of the wafer, and flows
downward on the peripheral surface (end surface) of the wafer from
the periphery of the wafer. An unwanted metal thin film formed on
the peripheral portion of the upper surface and the peripheral
surface of the wafer is thus removed.
[0015] Even with the use of this related art, however, it is
difficult to control accurately a width (etching width) of a region
on the upper surface of the wafer, from which a metal thin film is
to be removed. In other words, according to the arrangement to
scatter the etching liquid on the upper surface of the blocking
plate forcedly by a centrifugal force, it is difficult to fix a
supply position of the etching liquid on the upper surface of the
wafer, which may possibly vary the width of the region on the upper
surface of the wafer, from which the metal thin film is to be
removed.
[0016] In addition, in either of the foregoing related arts, the
shape of the region (region subject to processing) on the upper
surface of the wafer, to which processing is applied with the use
of processing liquid, is limited to an annular shape, and the
processing with the use of processing liquid cannot be applied to a
region of any other shape.
[0017] On the other hand, according to the related art using the
etching liquid that comes around the lower surface to the upper
surface of the wafer, in a case where a wafer subject to processing
is a wafer having a hydrophobic surface (for example, an
impurity-undoped polysilicon wafer), there is a problem that the
etching liquid supplied to the lower surface of the wafer cannot
come around to the upper surface of the wafer easily, and fails to
remove a metal thin film formed on the peripheral portion of the
upper surface of the wafer.
[0018] On the contrary, according to the arrangement to scatter the
etching liquid on the upper surface of the blocking plate forcedly
by a centrifugal force, the etching liquid can be supplied to the
peripheral portion of the upper surface of the wafer regardless of
whether the surface of the wafer is hydrophobic or hydrophilic.
According to this arrangement, however, the supply position of the
etching liquid on the upper surface of the wafer changes in
response to slightest variance in the rotational speed of the
blocking plate or a flow rate of the etching liquid supplied to the
blocking plate. This makes it difficult to control the etching
width on the upper surface of the wafer with accuracy.
SUMMARY OF THE INVENTION
[0019] It is therefore a first object of the invention to provide a
substrate processing apparatus and a substrate processing method
capable of controlling precisely a processing width in a peripheral
portion of the surface of a substrate.
[0020] A second object of the invention is to provide a substrate
processing apparatus and a substrate processing method capable of
controlling a width or a shape of a region to be processed with the
use of processing liquid on an upper surface of the substrate with
accuracy.
[0021] A third object of the invention is to provide a substrate
processing apparatus and a substrate processing method capable of
applying processing with the use of processing liquid to a region
subject to processing of an arbitrary shape on the upper surface of
the substrate.
[0022] A fourth object of the invention is to provide a substrate
processing apparatus and a substrate processing method capable of
applying processing with the use of processing liquid to a
peripheral portion of a substrate even when the substrate has a
hydrophobic surface as well as controlling a width of a region to
be processed with the use of processing liquid in the peripheral
portion of the substrate with accuracy.
[0023] A first aspect of a substrate processing apparatus of the
invention is an apparatus that removes an unwanted material on a
surface of a peripheral portion of a substrate through etching by
supplying etching liquid to the surface of the peripheral portion.
The substrate processing apparatus includes an etching liquid
supplying mechanism that supplies the etching liquid to the
peripheral portion of the substrate, and an annular member that has
an inner periphery on or inside an outer periphery of the substrate
and thereby defines a processing width to be processed by the
etching liquid on the surface of the peripheral portion of the
substrate.
[0024] According to this arrangement, the annular member is placed
so as to secure a certain gap with respect to the surface of the
peripheral portion of the substrate. The annular member includes
the inner periphery on or inside the outer periphery of the
substrate, and thereby defines an etching processing width on the
surface of the peripheral portion of the substrate.
[0025] The annular member may be placed in close proximity to the
surface of the peripheral portion of the substrate while securing a
certain gap such that allows the annular member to come in contact
with a liquid film of the etching liquid formed on the surface of
the peripheral portion. In this case, the etching liquid supplied
from the etching liquid supplying mechanism forms a liquid film on
the peripheral portion of the surface of the substrate. However,
because the annular member comes in contact with the liquid film,
the etching liquid is limited in the vicinity of the inner
periphery of the annular member, which makes it possible to prevent
the etching liquid from entering an inner region of the substrate.
It is thus possible to apply etching processing to the peripheral
portion of the substrate with an accurate processing width in a
satisfactory manner.
[0026] The substrate may be a substrate of a nearly circular shape,
such as a semiconductor wafer, or a substrate of a rectangular
shape, such as a glass substrate for a liquid crystal display.
[0027] Because the inner periphery of the annular member forms a
shape corresponding to the outer periphery of the substrate, the
inner periphery is of a nearly circular shape when a substrate of a
nearly circular shape is processed, and of a rectangular shape when
a substrate of a rectangular shape is processed.
[0028] The substrate processing apparatus may further include a
substrate holding mechanism that holds the substrate from one
surface side, and the annular member may be placed on the other
surface side of the substrate.
[0029] According to this arrangement, the peripheral portion of the
substrate can be processed by holding the substrate from one
surface side by the substrate holding mechanism while placing the
annular member on the other surface side.
[0030] For example, it may be arranged in such a manner that the
substrate holding mechanism holds the substrate from below, and the
annular member is placed in close proximity to the upper surface
side of the substrate.
[0031] In this case, the etching liquid can be supplied to the
peripheral portion of the substrate from the etching liquid
supplying mechanism while the substrate is held at rest (in a
non-rotating state or a low-speed rotating state (at a speed low
enough to prevent the etching liquid from spilling over from the
substrate)). In other words, a mound of the etching liquid can be
placed on the peripheral portion of the substrate, so that the
unwanted material on the peripheral portion of the surface of the
substrate is removed through etching by a mound of the etching
liquid thus placed. Because the annular member operates to control
a liquid film of a mound of the etching liquid so as not to enter
an inner side of the substrate, an etching width can be defined
with satisfactory accuracy.
[0032] A quantity of consumed etching liquid can be reduced
markedly by applying processing to the peripheral portion by
placing a mound of the etching liquid on the substrate. In
particular, by adopting the arrangement that allows the annular
member to come in contact with the liquid film, the etching liquid
can be held stably in a gap between the annular member and the
peripheral portion of the surface of the substrate. It is thus
possible to control the etching liquid so as not to enter an inner
side of the substrate or spill out from the substrate. Further, a
quantity of consumed etching liquid can be reduced markedly.
[0033] The state expressed as "the substrate held at rest" means a
state where the substrate is not rotating or moving, or a
substantially equivalent state. To be more specific, a state
equivalent to a state where the substrate is not rotating includes
a state where the substrate on which is placed a mound of the
etching liquid is rotated at a speed low enough to prevent the
etching liquid from spilling out from the substrate by a
centrifugal force. Also, a state equivalent to a state where the
substrate is not moving includes a state where the substrate is
moved spatially (movement in a vertical, horizontal, or diagonal
direction) at an accelerating speed low enough to prevent a mound
of the etching liquid placed on the substrate from spilling over
from the substrate by inertia.
[0034] The substrate may be a substrate of a nearly circular shape.
In this case, it is preferable that the apparatus further includes
a substrate rotating mechanism that rotates the substrate, and the
inner periphery of the annular member is of a circular shape having
an inside diameter equal to or smaller than a diameter of the
substrate.
[0035] According to this arrangement, the substrate is a substrate
of a nearly circular shape, and the substrate is rotated by the
substrate rotating mechanism. For example, the substrate rotating
mechanism may include a substrate holding mechanism that holds a
substrate and a rotational driving mechanism that rotates the
substrate holding mechanism.
[0036] It is preferable that the annular member is driven to rotate
in sync with rotations of the substrate (that is, in the same
rotational direction at the same rotational speed as the
substrate). However, the annular member may be held at rest or
rotated at a rotational speed different from the rotational speed
of the substrate. When the annular member is driven to rotate in
sync with the rotations of the substrate, the annular member may be
driven to rotate synchronously by a rotational driving mechanism
different from the rotational driving mechanism described above.
Alternatively, the annular member may be placed on the substrate
holding mechanism, so that both the substrate holding mechanism and
the annular member are rotated by the rotational driving mechanism
described above.
[0037] It is preferable that the substrate processing apparatus is
arranged in such a manner that the etching liquid is supplied to
the peripheral portion of the substrate from the etching liquid
supplying mechanism while the substrate is rotated by the substrate
rotating mechanism.
[0038] According to this arrangement, the etching liquid is
supplied to the peripheral portion of the substrate from the
etching liquid supplying mechanism when the substrate is in a
rotating state. In this instance, although a liquid film of the
etching liquid is formed on the peripheral portion of the
substrate, the annular member operates to control the liquid film
of the etching liquid not to enter an inner region of the
substrate.
[0039] It is preferable that the annular member includes a
substrate-opposing surface that extends outwards from the inner
periphery and opposes the surface of the peripheral portion of the
substrate.
[0040] According to this arrangement, for example, a liquid film of
the etching liquid can be brought into contact with the
substrate-opposing surface, which allows the liquid film to be
present in a space between the substrate-opposing surface and the
surface of the peripheral portion of the substrate. It is thus
possible to form a stable liquid film of the etching liquid across
the entire surface of the peripheral portion of the substrate in a
reliable manner, and as a consequence, more reliable, homogeneous
etching processing can be achieved.
[0041] By making the substrate-opposing surface as a plane nearly
parallel to the surface of the peripheral portion of the substrate,
a more stable liquid film of the etching liquid can be formed.
[0042] The substrate-opposing surface may be an inclined plane
inclined to reduce an interval between the substrate-opposing
surface and the substrate as heading toward the inner
periphery.
[0043] The inclined plane may be a plane or a curved plane. When
the annular member has an inner periphery of a nearly circular
shape, the inclined plane may be a conical plane or a curved plane
curved in a concave or convex shape with respect to the conical
plane.
[0044] According to this arrangement, because the
substrate-opposing surface is the inclined plane of a shape such
that nears the substrate as it heads toward the inside of the
substrate, not only can the etching liquid be introduced into a gap
between the substrate-opposing surface and the surface of the
peripheral portion of the substrate in a reliable manner, but also
entrance of the etching liquid into an inner region of the
substrate can be prevented more effectively.
[0045] It is preferable that an outer periphery of the
substrate-opposing surface is located outside the outer periphery
of the substrate. According to this arrangement, for example, when
the etching liquid is supplied from the surface of the substrate on
the opposite side to the surface of the peripheral portion of the
substrate, the etching liquid that comes around the end surface of
the substrate can be trapped by the substrate-opposing surface in a
satisfactory manner, and the etching liquid can be thereby
introduced into a gap between the substrate-opposing surface and
the surface of the peripheral portion of the substrate.
[0046] For example, when it is arranged in such a manner that the
substrate is held almost horizontally and rotated about the
rotational axis line passing through the center of the substrate
while the annular member is placed on the upper surface side of the
substrate, the etching liquid supplied on the lower surface side of
the substrate is forced to flow on the lower surface of the
substrate by a centrifugal force, and comes around the end surface
to the peripheral portion of the upper surface of the substrate. In
this instance, when the outer periphery of the substrate-opposing
surface is located outside the outer periphery of the substrate,
the etching liquid coming around the end surface of the substrate
can be trapped in a satisfactory manner, and can be thereby
introduced to the peripheral portion of the upper surface of the
substrate in a reliable manner.
[0047] It is preferable that the annular member includes a
projection that protrudes from the substrate-opposing surface
toward the substrate and thereby limits the etching liquid heading
toward an inside of the substrate.
[0048] It is preferable that the projection is a continuous
projection strip formed in the peripheral portion of the substrate
along the entire circumference in line with the inner periphery of
the annular member.
[0049] According to this arrangement, the operation of the
projection can prevent a liquid film of the etching liquid from
entering an inner region of the substrate in a more reliable
manner. It is thus possible to further improve accuracy of the
etching width.
[0050] It is preferable that the projection includes, on an outer
side of the annular member, an etching liquid limiting surface
composed of an inclined plane that heads toward an outside of the
substrate as moving away from a surface of the substrate.
[0051] Because the projection includes the etching limiting surface
composed of an inclined plane on an outer side of the substrate,
the etching limiting surface conforms to a shape of droplets of the
etching liquid. It is thus possible to prevent the etching liquid
from entering an inner region of the substrate in a more reliable
manner.
[0052] It is preferable that the annular member includes a liquid
discharge path that opens in the substrate-opposing surface and
communicates with an external space of the annular member.
[0053] According to this arrangement, the etching liquid between
the substrate-opposing surface and the surface of the peripheral
portion of the substrate can be discharged to an external space of
the annular member through the liquid discharge path.
[0054] To be more specific, when the surface of the peripheral
portion of the substrate is processed while the substrate and the
annular member are rotated, it is possible to pump out the etching
liquid that forms a liquid film between the substrate-opposing
surface and the substrate by exploiting a centrifugal force acting
on the etching liquid coming inside the liquid discharge path.
Thus, when the etching processing is performed while the etching
liquid is supplied to a space between the substrate-opposing
surface and the substrate continuously or intermittently, extra
etching liquid in the space between the substrate-opposing surface
and the substrate can be discharged through the liquid discharge
path, and new etching liquid can be thereby supplied to the liquid
film. It is thus possible to maintain the etching ability of the
etching liquid, which in turn reduces a processing time.
[0055] It is preferable that the liquid discharge path is provided
to open in the vicinity of the inner periphery of the annular
member. Alternatively, the liquid discharge path may be formed in
the projection to open in the surface opposing the substrate.
Further, it is preferable to set a rotational speed of the annular
member higher than a rotational speed of the substrate holding
mechanism in promoting discharge of the etching liquid through the
liquid discharge path.
[0056] It is preferable that the etching liquid supplying mechanism
includes a liquid dispense path made in the annular member and
including a dispense port that opens in the substrate-opposing
surface. According to this arrangement, the etching liquid can be
supplied directly to a space between the substrate-opposing surface
and the peripheral portion of the surface of the substrate in a
reliable manner.
[0057] It is preferable that the etching liquid supplying mechanism
includes a dispense port that opens in the substrate-opposing
surface, a liquid-receiving portion that communicates with the
dispense port, and a nozzle that supplies the liquid-receiving
portion with the etching liquid. According to this arrangement, the
etching liquid can be supplied directly to a space between the
substrate-opposing surface and the surface of the peripheral
portion of the substrate by supplying the etching liquid to the
liquid-receiving portion from the nozzle. Also, for example, even
when the annular member is rotated, the etching liquid can be
supplied by a simple arrangement.
[0058] To be more concrete, it is sufficient to arrange in such a
manner that the annular member is placed so that the
substrate-opposing surface opposes the substrate from above, and
the liquid-receiving portion is formed in an upper surface of the
annular member.
[0059] It is preferable that the etching liquid supplying mechanism
includes a nozzle that supplies the etching liquid toward a surface
of the substrate on an opposite side to a surface containing the
surface of the peripheral portion.
[0060] According to this arrangement, the etching liquid is
supplied to the surface of the substrate on the opposite side to
the surface of the peripheral portion, which is a region to be
processed, and the etching liquid thus supplied is introduced to
the surface of the peripheral portion by coming around the end
surface of the substrate, which allows the etching liquid to form a
stable liquid film with the annular member in a concerted
manner.
[0061] In order to introduce the etching liquid supplied to the
surface on the opposite side to the surface of the peripheral
portion, it is preferable to rotate the substrate, so that the
etching liquid supplied from the nozzle is introduced to the end
surface of the substrate by a centrifugal force. Also, when the
substrate is a circular substrate, the etching liquid can be
supplied to the surface of the peripheral portion of the substrate
in a more satisfactory manner.
[0062] The nozzle may supply the etching liquid toward a central
portion of the surface on the opposite side or it may supply the
etching liquid toward the vicinity of the peripheral portion of the
surface on the opposite side.
[0063] The etching liquid supplying mechanism may include a nozzle
that supplies the etching liquid toward an outer wall surface of
the annular member. According to this arrangement, the etching
liquid is introduced to the peripheral portion of the surface of
the substrate by flowing on the outer wall surface of the annular
member to form a liquid film.
[0064] The etching liquid supplying mechanism may include a
dispense port through which the etching liquid is dispensed in one
of a direction perpendicular to a surface of the substrate and a
direction inclined toward an outside of the substrate.
[0065] It is preferable that the annular member includes an inner
wall surface that rises from the inner periphery in a direction to
go away from a surface of the substrate.
[0066] According to this arrangement, it is possible to prevent a
liquid film of the etching liquid from entering an inner region of
the substrate further from the vicinity of the inner wall surface
of the annular member in a reliable manner. The inner wall surface
may be a plane along a vertical direction or an inclined plane
inclined with respect to a horizontal direction.
[0067] It is preferable that the inner wall surface is an inclined
plane that heads toward a center of the substrate as moving away
from the surface of the substrate.
[0068] According to this arrangement, when a liquid film of the
etching liquid tries to move toward the inside of the substrate by
surmounting the inner wall surface of the annular member, the
liquid film is introduced to the inner wall surface side of the
annular member, and as a consequence, fails to head to an inner
region of the substrate. It is thus possible to control more
precisely a region where a film of the etching liquid is present.
In particular, when the annular member is rotated, even if the
etching liquid tries to head toward the inside of the substrate by
flowing on the inner wall surface, the etching liquid is forced
back toward the outside of the substrate by a centrifugal force and
gravity. This arrangement can thus prevent the etching liquid from
entering an inner region of the substrate more effectively.
[0069] It is preferable that the substrate processing apparatus
further includes a lid member that substantially clogs an internal
space of the annular member.
[0070] According to this arrangement, droplets or mist of the
etching liquid present in an external space of the annular member
will not reach the central region of the substrate by passing
through the annular member. The surface of the peripheral portion
can be thus processed in a satisfactory manner without giving any
damage to the central region of the substrate. Moreover, because
the liquid film seals a space between the annular member and the
surface of the peripheral portion of the substrate, there is no
possibility that droplets or mist in the exterior of the annular
member will reach an inner region of the substrate by passing
through a gap between the annular member and the surface of the
peripheral portion of the substrate. An inner region of the
substrate can be thus protected in a reliable manner.
[0071] The lid member may be formed integrally with the annular
member or may be a separate member from the annular member.
[0072] It is preferable that the annular member includes an annular
groove formed adjacently inside the inner periphery. According to
this arrangement, because the etching liquid is not allowed to
reach the central region of the substrate by passing through the
annular groove, accuracy of the etching width can be improved
further.
[0073] It is preferable that the substrate processing apparatus
further includes a gas supplying mechanism that supplies an
internal space of the annular member with a gas. According to this
arrangement, it is possible to prevent a liquid film or droplets of
the etching liquid from reaching an inner region of the substrate
in a more reliable manner.
[0074] It is preferable that the annular member includes an inner
wall surface that rises from the inner periphery in a direction to
move away from a surface of the substrate, and the gas supplied
from the gas supplying mechanism is supplied toward the inner wall
surface.
[0075] According to this arrangement, when a gas is supplied toward
the inner wall surface of the annular member, the gas flows on the
inner wall surface of the annular member toward the surface of the
peripheral portion of the substrate. This prevents a liquid film of
the etching liquid from being introduced to the central region of
the substrate in a more reliable manner.
[0076] It is preferable that the annular member includes a gas
flowing path that allows a communication between an internal space
and an external space of the annular member.
[0077] According to this arrangement, a pressure difference between
the inside and the outside of the annular member can be controlled
by allowing a gas to flow between the inside and the outside of the
annular member through the gas flowing path. This prevents an
unwanted event that an internal pressure of the annular member
rises above an external pressure to the extent that breaking occurs
in a liquid film of the etching liquid formed on the surface of the
peripheral portion of the substrate. It is thus possible to apply
etching processing to the peripheral portion of the substrate along
the entire circumference in a satisfactory manner.
[0078] This arrangement is particularly effective when the lid
member substantially clogs an internal space of the annular
member.
[0079] It is preferable that the substrate processing apparatus
further includes a protection liquid supplying mechanism that
supplies etching protection liquid toward a center of the substrate
at an inner side of the annular member. According to this
arrangement, because the etching protection liquid can protect the
central portion of the substrate, damages to the central region of
the substrate can be prevented in a more reliable manner.
[0080] The etching liquid protection liquid may be, for example,
deionized water, carbonated water, hydrogenated water, reduced
water, ionized water, a magnetized water, etc.
[0081] A first aspect of a substrate processing method of the
invention is a substrate processing method of removing an unwanted
material on a surface of a peripheral portion of a substrate
through etching by supplying etching liquid to the surface of the
peripheral portion. The method includes a step of placing a mound
of the etching liquid on the surface of the peripheral portion of
the substrate while the substrate is held at rest, and a step of
placing an annular member, having an inner periphery on or inside
an outer periphery of the substrate, in close proximity to the
surface of the peripheral portion of the substrate and thereby
defining a processing width to be processed by the etching liquid
on the surface of the peripheral portion of the substrate.
[0082] A second aspect of the substrate processing method of the
invention includes: a step of performing, in parallel, (a) a
substrate rotating step of rotating the substrate, and (b) an
etching liquid supplying step of supplying the etching liquid to
the surface of the peripheral portion of the substrate being
rotated; and a step of placing an annular member, having an inner
periphery on or inside an outer periphery of the substrate, in
close proximity to the surface of the peripheral portion of the
substrate and thereby defining a processing width to be processed
by the etching liquid on the surface of the peripheral portion of
the substrate.
[0083] It is preferable that the etching liquid supplying step
includes a step of supplying the etching liquid toward a surface of
the substrate on an opposite side to a surface containing the
surface of the peripheral portion.
[0084] It is preferable that the annular member is placed in close
proximity to the surface of the peripheral portion of the substrate
while securing a certain gap such that allows the annular member to
come in contact with a liquid film of the etching liquid formed on
the surface of the peripheral portion of the substrate.
[0085] It is preferable that the method further includes a gas
supplying step of supplying an internal space of the annular member
with a gas.
[0086] It is preferable that the method further includes a
protection liquid supplying step of supplying etching protection
liquid to a central region of the substrate at an inner side of the
annular member.
[0087] A second aspect of the substrate processing apparatus of the
invention is a substrate processing apparatus that applies
processing to a peripheral portion of a substrate with the use of
processing liquid. The substrate processing apparatus includes: a
substrate holding mechanism that holds the substrate almost
horizontally and rotates the substrate about a nearly vertical
rotational axis line; an opposing member that includes a
substrate-opposing surface opposing an upper surface of the
substrate held by the substrate holding mechanism and having a
hydrophobic property at least in a peripheral portion region, and a
hydrophilic upper surface inclined to near an end edge of the
substrate-opposing surface as heading downward, the opposing member
protecting a central portion of the upper surface of the substrate
by brining the substrate-opposing surface in close proximity to the
upper surface of the substrate; and a processing liquid supplying
mechanism that supplies the processing liquid to the upper surface
of the opposing member.
[0088] According to the above arrangement, the upper surface of the
opposing member is a hydrophilic surface and at least the
peripheral portion region of the substrate-opposing surface is a
hydrophobic surface. The processing liquid flowing down from the
opposing member thereby flows down along the upper surface of the
opposing member in a satisfactory manner without spilling over from
the upper surface of the opposing member, then flows vertically
downward from the end edge of the substrate-opposing surface of the
opposing member without falling down by coming around to the
substrate-opposing surface of the opposing member, and is supplied
to the peripheral portion of the upper surface of the substrate at
a fixed position. This eliminates variance in width of a region to
be processed with the use of the processing liquid on the upper
surface of the substrate, and a width of the region to be processed
can be controlled accurately compared with a conventional
apparatus.
[0089] Also, because the central portion (for example, a
device-forming region) of the substrate, which is a region not to
be processed, is protected by the opposing member, it is possible
to prevent the central portion of the upper surface of the
substrate from undergoing unwanted processing.
[0090] The opposing member may be formed in a shape of a rotational
body having an axis line nearly along the rotational axis line as a
central axis line.
[0091] A third aspect of the substrate processing apparatus of the
invention is a substrate processing apparatus that applies
processing, with the use of processing liquid, to a region to be
processed including at least part of a peripheral portion of a
substrate. The substrate processing apparatus includes: a substrate
holding mechanism that holds the substrate; an opposing member that
includes a substrate-opposing surface opposing an upper surface of
the substrate held by the substrate holding mechanism and having an
end edge corresponding to a boundary set on the upper surface of
the substrate to divide the region to be processed and a region not
to be processed as well as having a hydrophobic property at least
in a peripheral portion region, and an hydrophilic upper surface
inclined to near the end edge of the substrate-opposing surface as
heading downward, the opposing member protecting the region not to
be processed on the upper surface of the substrate by bringing the
substrate-opposing surface in close proximity to the upper surface
of the substrate; and a processing liquid supplying mechanism that
supplies the processing liquid to the upper surface of the opposing
member.
[0092] According to this arrangement, the upper surface of the
opposing member is a hydrophilic surface and at least the
peripheral portion region of the substrate-opposing surface is a
hydrophobic surface. The processing liquid flowing down from the
opposing member thereby flows down along the upper surface of the
opposing member in a satisfactory manner without spilling over
outwards from the upper surface of the opposing member, then flows
vertically downward from the end edge of the substrate-opposing
surface of the opposing member without falling down by coming
around to the substrate-opposing surface of the opposing member,
and is supplied to the region to be processed on the upper surface
of the substrate. It is thus possible to apply processing with the
use of the processing liquid to a region to be processed of an
arbitrary shape. Moreover, this eliminates the possibility of
variance in width or shape of the region to be processed.
[0093] Also, because the region not to be processed on the upper
surface of the substrate is protected by the opposing member, there
is no possibility that the region not to be processed on the upper
surface of the substrate undergoes unwanted processing.
[0094] Further, by rotating the substrate about an axis that
intersects at right angles with the substrate by the substrate
holding mechanism, the region to be processed can be an annular
region in the peripheral portion of the substrate.
[0095] Also, the opposing member may further include a hydrophilic
side surface that connects the end edge of the substrate-opposing
surface and an end edge of the upper surface of the opposing
member. In this case, the side surface is preferably a plane
extending in a vertical direction, because such a side surface can
confer a vertically downward velocity vector to the processing
liquid flowing down on the side surface toward the end edge of the
substrate-opposing surface. This in turn makes it possible to guide
and supply the processing liquid to the fixed position (on the
boundary) on the upper surface of the substrate with good
accuracy.
[0096] Also, it is preferable that the substrate processing
apparatus further includes an inert gas supplying mechanism that
supplies an inert gas to a space between the upper surface of the
substrate held by the substrate holding mechanism and the
substrate-opposing surface. By supplying an inert gas to a space
between the upper surface of the substrate and the
substrate-opposing surface of the opposing member, it is possible
to prevent the central portion or a region not to be processed on
the upper surface of the substrate from under going unwanted
processing in a more reliable manner.
[0097] A third aspect of the substrate processing method of the
invention is a method of applying processing to a peripheral
portion of a substrate with the use of processing liquid. The
method includes: a substrate rotating and holding step of rotating
the substrate about a nearly vertical rotational axis line in an
almost horizontal posture by a substrate holding mechanism; an
opposing member approximating step of bringing an opposing member,
provided with a substrate-opposing surface opposing an upper
surface of the substrate held by the substrate holding mechanism
and having a hydrophobic property at least in a peripheral portion
region and a hydrophilic upper surface inclined to near an end edge
of the substrate-opposing surface as heading downward, in close
proximity to the upper surface of the substrate held by the
substrate holding mechanism; and a processing liquid supplying step
of supplying the processing liquid to the upper surface of the
opposing member in allowing the processing liquid to flow down to
the peripheral portion of the substrate held by the substrate
holding mechanism from the end edge of the substrate-opposing
surface.
[0098] A fourth aspect of the substrate processing method of the
invention includes: a substrate holding step of having a substrate
holding mechanism hold the substrate almost horizontally; an
opposing member approximating step of bringing an opposing member,
provided with a substrate-opposing surface opposing an upper
surface of the substrate held by the substrate holding mechanism
and having an end edge corresponding to a boundary set on the upper
surface of the substrate to divide the region to be processed and a
region not to be processed as well as having a hydrophobic property
at least in a peripheral portion region and a hydrophilic upper
surface inclined to near the end edge of the substrate-opposing
surface as heading downward, in close proximity to the upper
surface of the substrate held by the substrate holding mechanism;
and a processing liquid supplying step of supplying the processing
liquid to the upper surface of the opposing member in allowing the
processing liquid to flow down to the region to be processed of the
substrate held by the substrate holding mechanism from the end edge
of the substrate-opposing surface.
[0099] A fourth aspect of the substrate processing apparatus of the
invention is a substrate processing apparatus that applies
processing to a peripheral portion of a substrate with the use of
processing liquid. The substrate processing apparatus includes: a
substrate holding mechanism that holds the substrate almost
horizontally and rotates the substrate about a nearly vertical
rotational axis line; an opposing member placed oppositely to an
upper surface of the substrate held by the substrate holding
mechanism and including a projection strip protruding toward the
substrate at an edge portion; and a processing liquid supplying
mechanism that supplies the opposing member with the processing
liquid.
[0100] The opposing member may include a substrate-opposing surface
having the projection strip protruding toward the substrate at an
edge portion, and an upper surface connected to the projection
strip. In this case, the processing liquid supplying mechanism may
supply the processing liquid to the upper surface of the opposing
member. The projection strip may be provided to part of the edge
portion of the substrate-opposing surface of the opposing member,
or it may be a ring-shaped projection portion provided to the
peripheral portion of the substrate-opposing surface of the
opposing member along the entire circumference (across the entire
region).
[0101] According to the above arrangement, the processing liquid
supplied to the upper surface of the opposing member flows on the
upper surface. Then, because the upper surface of the opposing
member is connected to the projection strip, part of the processing
liquid flowing on the upper surface comes around the upper surface
to the projection strip, and flows downward to the peripheral
portion of the upper surface of the substrate from the projection
strip. It is thus possible to supply the processing liquid and
thereby to apply processing with use of the processing liquid to
the peripheral portion of the upper surface of the substrate
regardless of whether the upper surface of the substrate is
hydrophobic or hydrophilic.
[0102] It is preferable to connect the upper surface and the
projection strip of the opposing member smoothly with a rounded
plane having an arc-shaped convex-curved cross section. However,
the upper surface and the projection strip of the opposing member
are not necessarily connected to each other smoothly as long as the
processing liquid supplied to the upper surface of the opposing
member can come around to the projection strip. For example, the
upper surface and the projection strip of the opposing member may
be connected directly, and a connecting portion may form a
corner.
[0103] Also, because the substrate-opposing surface in the lower
surface of the opposing member is located higher than the
projection strip, the processing liquid coming around to the
projection strip flows vertically downward from the projection
strip without flowing to the substrate-opposing surface of the
opposing member. The processing liquid is thus supplied to the
upper surface of the substrate only at a region where the
projection strip opposes, and the processing liquid is never
supplied to a region inside the region where the projection strip
opposes. Also, because the processing liquid is supplied to the
upper surface of the substrate as flowing down from the projection
strip, the supply position of the processing liquid on the upper
surface of the substrate can remain at a fixed position. It is thus
possible to control a width of the region to be processed on the
upper surface of the substrate with accuracy.
[0104] Also, the projection strip of the opposing member may
include a lower end edge located above the peripheral portion of
the substrate held by the substrate holding mechanism. In this
case, when the projection strip includes the lower end edge (where
the projection strip includes a lower surface opposing the
substrate held by the substrate holding mechanism, the lower end
edge may be the lower surface), the processing liquid coming around
the upper surface of the opposing member to the projection strip is
supplied to a gap between the lower end edge of the projection
strip and the peripheral portion of the upper surface of the
substrate. It is thus possible to control a width of a region to be
processed with the use of the processing liquid on the upper
surface of the substrate, by controlling the position of the lower
end edge of the projection strip.
[0105] It is preferable that the upper surface of the opposing
member is inclined to near a periphery of the substrate held by the
substrate holding mechanism as heading downward. By inclining the
upper surface of the opposing member, the processing liquid
supplied to the upper surface of the opposing member can be
introduced to the projection strip in a satisfactory manner.
Further, when the upper surface of the opposing member includes a
hydrophilic property, the processing liquid supplied to the upper
surface of the opposing member can be introduced to the projection
strip in a more satisfactory manner.
[0106] The projection strip of the opposing member may include, in
a lower surface, a plane nearly parallel to the upper surface of
the substrate held by the substrate holding mechanism. However, it
is preferable that the projection strip of the opposing member
includes, in a lower surface, an inclined plane that nears the
upper surface of the substrate held by the substrate holding
mechanism as approaching the rotational axis line. The inclined
plane may be a plane having a cross section linearly inclined to
near the upper surface of the substrate held by the substrate
holding mechanism as it approaches the rotational axis line, or a
plane having a cross section convex-curved or concave-curved to
near the upper surface of the substrate held by the substrate
holding mechanism as it approaches the rotational axis line. When
the projection strip includes an inclined plane in the lower
surface, a large quantity of the processing liquid is allowed to
come around to the lower surface of the projection strip, which in
turn makes it possible to supply a large quantity of the processing
liquid to the upper surface of the substrate at a region where the
projection strip opposes.
[0107] Also, it is preferable that the projection strip of the
opposing member includes, in a lower surface, a hydrophilic surface
opposing the upper surface of the substrate held by the substrate
holding mechanism. This also allows a large quantity of the
processing liquid to come around to the lower surface of the
projection strip, which in turn makes it possible to supply a large
quantity of the processing liquid to the upper surface of the
substrate at a region where the projection strip opposes.
[0108] The substrate processing apparatus may further include an
opposing member rotating mechanism that rotates the opposing member
about the rotational axis line. According to this arrangement, for
example, by rotating the opposing member when the processing liquid
is supplied to the opposing member, it is possible to introduce the
processing liquid supplied to the upper surface of the opposing
member to the projection strip by a centrifugal force. Also, when
the processing to the substrate ends, the opposing member can be
dried by rotating the opposing member at a high speed in throwing
off the processing liquid adhering to the opposing member.
[0109] When the opposing member is rotated while the processing
liquid is supplied to the opposing member, it is preferable that
the opposing member rotating mechanism rotates the opposing member
at a rotational speed lower than a rotational speed at which the
substrate is rotated by the substrate holding mechanism. By so
doing, it is possible to prevent spilling over of the processing
liquid from the opposing member that would occur otherwise by a
centrifugal force induced by rotations of the opposing member and
that would hence make it difficult for the processing liquid to
come around to the peripheral portion of the upper surface of the
substrate.
[0110] A fifth aspect of the substrate processing method of the
invention is a method of applying processing to a peripheral
portion of a substrate with the use of processing liquid. The
method includes: a substrate rotating step of having a substrate
holding mechanism hold the substrate almost horizontally and
rotating the substrate about a nearly vertical rotational axis
line; an opposing member approximating step of bringing an opposing
member, placed oppositely to an upper surface of the substrate held
by the substrate holding mechanism and including a projection strip
protruding toward the substrate at an edge portion, in close
proximity to the substrate held by the substrate holding mechanism;
and a processing liquid supplying step of supplying the processing
liquid to the opposing member in allowing the processing liquid to
flow down to the peripheral portion of the substrate held by the
substrate holding mechanism from the projection strip.
[0111] The opposing member may include a substrate-opposing surface
having the projection strip at an edge portion and an upper surface
connected to the convex strip. In this case, the processing liquid
supplying step may include a step of supplying the processing
liquid to the upper surface of the opposing member.
[0112] The above and other objects, features, and advantages of the
invention will become more apparent from the following description
of embodiments with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0113] FIG. 1 is a cross sectional view used to explain an
arrangement of a substrate periphery processing apparatus according
to a first embodiment of the invention;
[0114] FIG. 2 is an enlarged cross sectional view used to explain
an arrangement in close proximity to an annular member that
controls a liquid film of etching liquid on a peripheral portion of
the surface of a wafer;
[0115] FIG. 3 is a cross sectional view used to explain an
arrangement of a substrate periphery processing apparatus according
to a second embodiment of the invention;
[0116] FIG. 4 is a cross sectional view used to explain an
arrangement of a substrate periphery processing apparatus according
to a third embodiment of the invention;
[0117] FIG. 5(a) through FIG. 5(g) are partially enlarged cross
sectional views used to explain various configurations of an
annular member;
[0118] FIG. 6(a) through FIG. 6(c) are cross sectional views
showing modifications as to the shape of an inner wall surface of
the annular member;
[0119] FIG. 7(a) through FIG. 7(c) are cross sectional views
showing modifications as to the shape of a wafer-opposing surface
of the annular member;
[0120] FIG. 8(a) through FIG. 8(e) are cross sectional views
showing modifications of a guide edge portion provided to the wafer
opposing surface of the annular member;
[0121] FIG. 9(a) through FIG. 9(h) are schematic cross-sectional
views showing examples of a configuration to supply the etching
liquid to the peripheral portion of the upper surface of the
wafer;
[0122] FIG. 10 is a view schematically showing an arrangement of a
substrate periphery processing apparatus according to a fourth
embodiment of the invention;
[0123] FIG. 11 is a cross sectional view showing a way in which the
etching liquid flows down;
[0124] FIG. 12 is a plan view used to explain a fifth embodiment of
the invention;
[0125] FIG. 13 is a plan view used to explain a sixth embodiment of
the invention;
[0126] FIG. 14 is a view schematically showing an arrangement of a
substrate processing apparatus according to a seventh
embodiment;
[0127] FIG. 15 is a schematic cross sectional view showing a way in
which etching processing is performed;
[0128] FIG. 16 is a schematic cross sectional view used to explain
another arrangement (first modification) of an opposing member;
[0129] FIG. 17 is a schematic cross sectional view used to explain
a further arrangement (second modification) of the opposing
member;
[0130] FIG. 18 is a schematic cross sectional view used to explain
still another arrangement (third modification) of the opposing
member; and
[0131] FIG. 19 is a plan view used to explain still another
arrangement (fourth modification) of the opposing member.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0132] FIG. 1 is a cross sectional view used to explain an
arrangement of a substrate periphery processing apparatus according
to one embodiment of the invention. The substrate periphery
processing apparatus has the ability to remove a thin film formed
on the peripheral portion of the surface (the upper surface,
herein) and the end surface of a semiconductor wafer (hereinafter,
referred to simply as the wafer) W, which is a substrate of a
nearly circular shape. The substrate periphery processing apparatus
includes, inside a processing cup (not shown), a spin chuck 1 that
holds the wafer W almost horizontally with its back surface facing
downward, and rotates about the vertical axis line passing the
center or nearly the center of the wafer W thus held.
[0133] The spin chuck 1 is arranged in such a manner that it is
rotated as being coupled to a rotating shaft 3, which is a driving
shaft of a rotational driving mechanism 2 including a motor or the
like. The rotating shaft 3 is a hollow shaft, into which is
inserted a processing liquid supply pipe 4 where deionized water or
etching liquid is supplied. The top end of the processing liquid
supply pipe 4 is coupled to a central axis nozzle (stationary
nozzle) 5 having a dispense port Sa at a position in close
proximity to the center of the lower surface of the wafer W held by
the spin chuck 1. Deionized water or the etching liquid is supplied
toward the center of the lower surface of the wafer W through the
dispense port 5a of the central axis nozzle 5.
[0134] Deionized water or the etching liquid is supplied to the
processing liquid supply pipe 4 at necessary timing via a deionized
water supply valve 6 connected to a deionized water supply source
or via an etching liquid supply valve 7 connected to an etching
liquid supply source.
[0135] Used as the etching liquid is of a kind that corresponds to
the kind of a thin film to be removed from the surface of the
peripheral portion of the wafer W. More specifically, when a metal
film, such as a copper thin film, is to be removed from the surface
of the peripheral portion of the wafer W, for example, a liquid
mixture of hydrochloric acid and hydrogen peroxide solution, a
liquid mixture of hydrofluoric acid and hydrogen peroxide solution,
or nitric acid is used as the etching liquid. When a polysilicon
film, an amorphous silicon film or a silicon dioxide film is to be
removed from the wafer W, for example, a liquid mixture of
hydrofluoric acid and nitric acid is used as the etching liquid.
Further, when an oxide film or a nitride film on the wafer W is to
be removed, for example, hydrofluoric acids, such as DHF (dilute
hydrofluoric acid) and 50% hydrofluoric acid, are used as the
etching liquid.
[0136] A space between the processing liquid supply pipe 4 and the
rotating shaft 3 is used as a process gas supply path 8, which
communicates with a space below the wafer W in the surrounding of
the central axis nozzle 5. A process gas (for example, an inert
gas, such as a nitrogen gas) is supplied from a process gas supply
source to the process gas supply path 8 via a process gas supply
valve 9.
[0137] A disc-shaped blocking plate 10 is placed horizontally above
the spin chuck 1 to oppose the wafer W held by the spin chuck 1.
The blocking plate 10 is of a size large enough to cover the upper
surface of the wafer W almost entirely, and is allowed to move
upward/downward with respect to the spin chuck 1 by a blocking
plate elevator driving mechanism 11. The blocking plate 10 is also
rotated coaxially about the rotational axis line of the spin chuck
1 by a motor 12 serving as a blocking plate rotational driving
mechanism.
[0138] The motor 12 comprises a hollow motor in this embodiment,
and the blocking plate 10 is coupled to the lower end of a rotating
shaft 13 driven to rotate by the motor 12.
[0139] The rotating shaft 13 includes a hollow shaft, and a central
axis nozzle 14 is inserted therein. Deionized water from the
deionized water supply source is supplied to the central axis
nozzle 14 via a deionized water supply valve 15, and chemical
liquid (such as the etching liquid) from a chemical liquid supply
source is also supplied to the rotational axis nozzle 14 via a
chemical liquid supply valve 16. The lower end of the central axis
nozzle 14 fits in a through-hole 17 made in the blocking plate 10
at the center, and faces the center (rotational center) of the
upper surface of the wafer W held by the spin chuck 1.
[0140] A gap between the rotating shaft 13 as a hollow shaft and
the central axis nozzle 14 defines a process gas supply path 18,
and the process gas supply path 18 faces the vicinity of the center
of the upper surface of the wafer W through the through-hole 17 in
the blocking plate 10. A process gas (an inert gas, such as a
nitrogen gas) from the process gas supply source is supplied to the
process gas supply path 18 via a process gas supply valve 19.
[0141] Inside a housing 20 accommodating the motor 12 are provided
a bearing 21 that axially supports the rotating shaft 13, and a
process gas supplying mechanism 22 that supplies an internal space
of the blocking plate 10 with a process gas. The process gas
supplying mechanism 22 includes a tubular labyrinth member 23
having a labyrinth surface that opposes the outer peripheral
surface of the rotating shaft 13 as an inner peripheral surface,
and a process gas introduction port 24 coupled to a process gas
supply port 23a made in the labyrinth member 23.
[0142] The labyrinth member 23 is provided with an annular groove
23b in the labyrinth surface at a position corresponding to the
process gas supply port 23a. A seal gas supplied through a seal gas
introduction port 25 is supplied to labyrinth portions above and
below the annular groove 23b.
[0143] A process gas (an inert gas, such as a nitrogen gas) is
supplied from the process gas supply source to the process gas
introduction port 24 via a process gas supply valve 26, and a seal
gas (dry air or the like) is supplied from a seal gas supply source
to the seal gas introduction port 25 via a seal gas supply valve
27.
[0144] An internal atmosphere in the vicinity of the lower end of
the labyrinth member 23 is taken in and exhausted through an intake
port 28, so that the process gas or the seal gas will not leak into
the processing chamber.
[0145] The rotating shaft 13 is of a double-axis structure
comprising an inside axis 13A and an outside axis 13B surrounding
the inside axis 13A, and the lower end of the outside axis 13B is
supported by an outward flange 29 formed in the vicinity of the
lower end of the inside axis 13A. The outside axis 13B opens at a
position opposing the annular groove 23b of the labyrinth member
23, and a process gas path 30 is formed within the thickness to
extend in the axial direction. The process gas path 30 penetrates
through a through-hole made in the flange 29 and a through-hole
made in a top lid portion 31 of the blocking plate 10, and
communicates with the internal space of the blocking plate 10.
[0146] The process gas supplied through the process gas
introduction port 24 is introduced into the process gas path 30 in
the rotating shaft 13 while being sealed by a seal gas on the
labyrinth surface of the labyrinth member 23.
[0147] The blocking plate 10 is provided with the
circular-disc-shaped top lid portion 31, a cylindrical annular
member 32 coupled to the lower surface of the top lid portion 31 at
the peripheral portion, and a circular-disc-shaped center plate 33
coupled to the top lid portion 31 from below. The top lid portion
31, the annular member 32, and the center plate 33 together define
a gas space 34 inside the blocking plate 10. A process gas from the
process gas path 30 is introduced into the gas space 34.
[0148] A fine slit is formed between the center plate 33 and the
inner wall surface of the annular member 32 along the entire
circumference. The slit forms a gas nozzle 35 through which the
process gas is discharged toward the inner periphery of the lower
end of the annular member 32.
[0149] FIG. 2 shows an enlarged cross section in close proximity to
the annular member 32. The wafer W subject to processing is clamped
by a plurality of (for example, three) chuck pins 41 provided to
the spin chuck 1. Each chuck pin 41 is provided with a supporting
portion 42 that supports the peripheral portion of the lower
surface of the wafer W, and a guide pin 43 that abuts on the end
surface of the wafer W and thereby regulates a horizontal movement
of the wafer W.
[0150] The annular member 32 is located inside the guide pin 43 in
the direction of turning radius of the wafer W, and opposes the
peripheral portion of the upper surface of the wafer W above the
wafer W held by the spin chuck 1. To be more concrete, the annular
member 32 includes a wafer-opposing surface 45 that opposes the
surface of the peripheral portion of the upper surface of the wafer
W, a guide edge portion 46 protruding toward the surface of the
wafer W at the inner periphery of the wafer-opposing surface 45, an
inner wall surface 47 rising vertically upward (in a direction to
move away from the surface of the wafer W) from the inner periphery
of the guide edge portion 46, and an outer wall surface 48 rising
vertically upward from the outer periphery of the wafer-opposing
surface 45. The guide edge portion 46 is formed at the lower end of
the inner wall surface 47 of the annular member 32 along the entire
circumference, and thereby forms an annular convex strip.
[0151] A liquid film 50 of the etching liquid is formed in a gap
between the wafer-opposing surface 45 and the peripheral portion of
the wafer W. The liquid film 50 comes in contact with the
wafer-opposing surface 45 and its movement toward the inside of the
wafer W is limited by the guide edge portion 46.
[0152] Meanwhile, the center plate 33 includes, at the outer
periphery of the lower surface, which is the surface opposing the
wafer W, an annular groove (counter-bore portion) 51 that opens
outwards in the direction of radius, and a chamfered-corner portion
52 in the peripheral portion on the upper surface side that does
not oppose the wafer W. The chamfered-corner portion 52 narrows a
path of the process gas supplied to the gas nozzle 35 from the gas
space 34, and thereby allows the gas nozzle 35 to vigorously blow
out the process gas vertically downward to the upper surface of the
wafer W along the inner wall surface 47 of the annular member 32.
In other words, the process gas changes its direction to head
downward to the wafer W due to the presence of the inner wall
surface 47 of the annular member 32, and is blown out from the gas
nozzle 35 toward the upper surface of the wafer W along the inner
wall surface 47.
[0153] Degassing paths 49 that open both in the inner wall surface
47 and the outer wall surface 48 and thereby allow a communication
between an internal space of the annular groove 51 and an external
space of the blocking plate 10 are formed in the annular member 32
at positions opposing the annular groove 51. The degassing paths 49
comprise circular holes of a fine diameter (for example, 0.5 mm in
diameter), and a plurality of them are formed at equiangular
intervals (for example, 72 of them at 5.degree. intervals) in the
circumferential direction of the annular member 32. Even when the
liquid film 50 of the etching liquid is formed between the
wafer-opposing surface 45 and the surface of the peripheral portion
of the wafer W, the degassing paths 49 serve to eliminate a
pressure difference between a space 40 present between the blocking
plate 10 and the upper surface of the wafer W and the external
space of the blocking plate 10.
[0154] On the other hand, the guide edge portion 46 formed at the
inner periphery of the wafer-opposing surface 45 includes an
etching liquid limiting surface 46a on the outer side in the
direction of the turning radius of the wafer W. The etching liquid
limiting surface 46a forms an inclined plane (inverted conical
plane) heading outwards as it moves away from the wafer W. The
etching liquid limiting surface 46a conforms to the shape of the
liquid film 50 of the etching liquid, and thereby prevents the
liquid film 50 from entering the central region of the wafer W in a
reliable manner.
[0155] It is preferable that the inner wall surface 47 of the
annular member 32 is provided slightly outside (for example, 0.1 to
a few mm outside, the range, however, varies depending on the kinds
of the etching liquid and the surface conditions of the wafer W)
the inner periphery of the region subject to processing in the
peripheral portion of the upper surface of the wafer W (a region 3
to 5 mm inside the outer peripheral end of the wafer W). In other
words, it is preferable that the inner periphery of the annular
member 32 forms a circle having a diameter shorter than the
diameter of the wafer W, but slightly larger than the diameter of
the circle shaped by the inner periphery of the region subject to
processing in the peripheral portion of the upper surface of the
wafer W.
[0156] Although it depends on the kinds of the etching liquid and
the surface conditions of the wafer W, it is preferable to set the
interval between the wafer-opposing surface 45 and the surface of
the peripheral portion of the wafer W to 0.3 to 5 mm
approximately.
[0157] Likewise, it is preferable to set the interval between the
lower end (the portion in the closest proximity to the wafer W) of
the guide edge portion 46 and the surface of the wafer W to, for
example, 0.1 to 3 mm approximately, although the range varies with
the kinds of the etching liquid and the surface conditions of the
wafer W.
[0158] The annular groove 51 formed adjacently inside the inner
wall surface 47 of the annular member 32 is a groove recessed in a
direction to move away from the surface of the wafer W, and it is
preferable to set the width of the groove to 1 mm or greater.
[0159] As shown in FIG. 1, the spin chuck 1 is provided with a
disc-shaped spin base 441 and a spin chuck driving mechanism 44
that activates the chuck pins 41 provided to stand on the spin base
441. The chuck pin driving mechanism 44 includes, for example, a
linking mechanism 442 provided in the interior of the spin base 441
and a driving mechanism 443 that drives the linking mechanism 442.
The driving mechanism 443 is provided with a rotary-side driving
force delivery member 444 that rotates together with the rotating
shaft 3, a stationary-side driving force delivery member 446
coupled to the outer periphery of the rotary-side driving force
delivery member 444 through a bearing 445, and a chuck-pin-drive
elevator driving mechanism 447 that moves the stationary-side
driving force delivery member 446 upward/downward.
[0160] When the stationary-side driving force delivery member 446
is moved upward/downward by the chuck-pin-drive elevator driving
mechanism 447, the rotary-side driving force delivery member 444
starts to move upward/downward in association, and this elevator
motion is transferred to the linking mechanism 442 to be converted
into an operation of the chuck pins 41. Hence, by activating the
chuck-pin-drive elevator driving mechanism 447, it is possible to
clamp the wafer W by the chuck pins 41 or release the clamping.
Because the stationary-side driving force delivery member 446 and
the rotary-side driving force delivery member 444 are coupled to
each other through the bearing 445, the clamping position of the
wafer W can be changed even when the spin chuck 1 is rotating, by
releasing or relaxing the clamping of the wafer W by the chuck pins
41.
[0161] When the wafer W subject to processing is introduced to the
spin chuck 1, the blocking plate 10 is retracted to an evacuation
position away above the spin chuck 1 by the operation of the
blocking plate elevator driving mechanism 11. Under these
conditions, the unprocessed wafer W is delivered to the spin chuck
1 by an unillustrated substrate-transporting robot. Subsequently,
the wafer W is clamped by the chuck pins 41 by the operation of the
chuck pin driving mechanism 44.
[0162] Then, the blocking plate 10 is lowered toward the spin chuck
1 by the operation of the blocking plate elevator driving mechanism
11 until the center plate 33 is located in close proximity to the
central region of the wafer W while the annular member 32 is in
close proximity to the surface of the peripheral portion of the
wafer W. In this instance, for example, 0.5 mm is given as the
interval between the upper surface of the wafer W and the
wafer-opposing surface 45. The spin chuck 1 is driven to rotate by
the rotational driving mechanism 2, and the blocking plate 10 is
driven to rotate by the motor 12 under these conditions. In this
instance, the rotational driving mechanism 2 and the motor 12 are
controlled so that the spin chuck 1 and the blocking plate 10
rotate synchronously, that is, rotate in the same direction at
substantially the same rotational speed.
[0163] When the etching liquid supply valve 7 is opened under these
conditions, the etching liquid is supplied toward the center on the
back surface of the wafer W from the central axis nozzle 5. The
etching liquid is forced to flow on the lower surface of the wafer
W by a centrifugal force to the peripheral end surface, and reaches
the peripheral portion of the upper surface of the wafer W by
coming around the peripheral end surface.
[0164] As shown in FIG. 2, the liquid film 50 is formed in a gap
between the wafer-opposing surface 45 of the annular member 32 and
the surface of the peripheral portion of the wafer W. The liquid
film 50 comes in contact with the wafer-opposing surface 45 and
further comes in contact with the etching liquid limiting surface
46a of the guide edge portion 46. Because the inner side of the
guide edge portion 46 continues with the inner wall surface 47 that
stands upright or nearly upright with respect to the surface of the
wafer W, the liquid film 50 of the etching liquid cannot enter an
inner region of the wafer W far from the inner wall surface 47 of
the annular member 32. This makes it possible to control the
etching width in the peripheral portion of the upper surface of the
wafer W with high accuracy.
[0165] Meanwhile, either or both of the process gas supply valve 19
and the process gas supply valve 26 are opened, and the process gas
is supplied to the annular groove 51 from the gas space 34 and the
space 40 above the upper surface of the wafer W. Pressure applied
by the process gas can prevent the liquid film 50 of the etching
liquid from entering an inner region of the wafer W in a reliable
manner. The liquid film 50 seals an internal space of the annular
member 32 hermetically. However, because the internal space of the
annular groove 51 and the external space of the blocking plate 10
communicate with each other through the degassing paths 49,
breaking caused by a pressure difference between the inside and the
outside of the blocking plate 10 will not occur anywhere in the
liquid film 50.
[0166] When the etching processing is performed on the surface of
the peripheral portion of the wafer W for a predetermined time
under these conditions, the etching liquid supply valve 7 is
closed, and the blocking plate 10 is moved upward to a
predetermined height (for example, to a position at which 50 mm is
given as the interval between the wafer-opposing surface 45 and the
upper surface of the wafer W) by the blocking plate elevator
driving mechanism 11. Subsequently, the deionized water supply
valve 6 is opened, the process gas supply valve 26 is closed, and
the deionized water supply valve 15 is opened. Deionized water is
thereby supplied to the upper and lower surfaces of the wafer W to
perform deionized water rinsing processing that rinses the wafer W
with water.
[0167] Then, the deionized water supply valves 6 and 15 are closed,
and the blocking plate 10 is lowered again by the blocking plate
elevator driving mechanism 11 to come in close proximity to the
upper surface of the wafer W (for example, to a position at which
0.3 mm is given as the interval between the wafer-opposing surface
45 and the upper surface of the wafer W). The spin chuck 1 is
driven to rotate at a high speed under these conditions to perform
drying processing that removes water on the wafer W by throwing off
the water with a centrifugal force.
[0168] The process gas supply valves 9 and 19 remain open during
the processing of the wafer W and thereby maintain the upper and
lower surfaces of the wafer W in an inert gas atmosphere. Likewise,
the seal gas supply valve 27 remains open during the processing of
the wafer W, and thereby prevents an atmosphere from flowing in and
out from a path of the process gas.
[0169] As has been described, according to this embodiment, the
liquid film 50 of the etching liquid in the peripheral portion of
the wafer W is limited by the annular member 32 in a reliable
manner so as not to enter an inner region of the wafer W. This
makes it possible to control the etching width in the peripheral
portion of the wafer W with high accuracy as well as to apply the
processing to the peripheral portion of the wafer W in a
satisfactory manner.
[0170] FIG. 3 shows a cross section of a substrate periphery
processing apparatus according to a second embodiment of the
invention. In FIG. 3, components corresponding to those shown in
FIG. 1 are labeled with like reference numerals with respect to
FIG. 1.
[0171] In this embodiment, the spin base 441 of the spin chuck 1 is
provided with a plurality of receive pins 61 used to receive and
hold a blocking plate 60 at intervals in the circumferential
direction (for example, three of them at equiangular intervals).
The blocking plate 60 comprises a plate-shaped body having a major
diameter larger than the diameter of the wafer W, and is provided
with a plurality of through-holes 62 made in the peripheral portion
in the circumferential direction at intervals so as to engage with
the receive pins 61. The blocking plate 60 is held above the spin
base 441 as the lower surface is supported by shoulder portions 61a
of the receive pins 61 at the peripheral portions of the
through-holes 62, and is thereby driven to rotate together with the
spin base 441. The blocking plate 60, being held by the receive
pins 61, is located so that its lower surface 63 is in close
proximity to the upper surface of the wafer W held by the spin
chuck 1.
[0172] The blocking plate 60 includes a through-hole 64 at the
center, and includes an annular portion 65 integrally at a position
corresponding to the peripheral portion of the upper surface of the
wafer W. At an adjacent position inside the annular portion 65, an
annular groove 66 recessed in a direction to move away from the
wafer W is provided along the entire circumference. The portions of
the blocking plate 60 other than the annular portion 65 together
form a lid portion that substantially clogs a space surrounded by
the annular portion 65.
[0173] The annular portion 65 includes a wafer-opposing surface 67
that opposes the peripheral portion of the wafer W, a guide edge
portion 68 that protrudes to come in close proximity to the upper
surface of the wafer W at the inner periphery of the wafer-opposing
surface 67, an inner wall surface 69 that rises from the guide edge
portion 68 vertically upward in a direction to move away from the
wafer W, and an outer wall surface 70 that rises from the periphery
of the wafer-opposing surface 67 on the outer side in the direction
of the turning radius. The inner periphery of the wafer-opposing
surface 67 is of a circular shape having a diameter smaller than
the diameter of the wafer W. The circle shaped by the inner
periphery is slightly larger than the inner periphery of the region
subject to processing in the peripheral portion of the upper
surface of the wafer W.
[0174] A flange pipe 71 including an internal space that
communicates with a through-hole 64 is coupled to the upper surface
of the blocking plate 60. Further, a blocking plate flange 72
including a through-hole at the center is coupled to the top end of
the flange pipe 71. A central axis nozzle 75 is provided to
penetrate through the through-hole at the center of the blocking
plate flange 72 and the internal space of the flange pipe 71 to
reach the through-hole 64.
[0175] The central axis nozzle 75 comprises a double-pipe including
a processing liquid supply pipe 76 and a process gas supply pipe
77, and therefore has the ability to supply processing liquid
(deionized water or chemical liquid) to the upper surface of the
wafer W from the processing liquid supply pipe 76 as well as to
supply the process gas to a space between the upper surface of the
wafer W and the blocking plate 60 from a space between the
processing liquid supply pipe 76 and the process gas supply pipe
77. The process gas heads outwards in the direction of the radius
of the wafer W by flowing on the upper surface thereof, then
collides with the inner wall surface 69 of the annular portion 65,
and moves downward to the upper surface of the wafer W along the
inner wall surface 69.
[0176] As with the first embodiment described above, the annular
portion 65 is provided with a number of degassing paths 80 made in
the circumferential direction at intervals to allow a communication
between the inner wall surface 69 and the outer wall surface
70.
[0177] A blocking-plate-side labyrinth member 73 is fixed onto the
upper surface of the blocking plate flange 72, and a nozzle-side
labyrinth member 74 is coupled to the blocking-plate-side labyrinth
member 73 in a non-contact state. A seal gas (purge gas) is
supplied to a space between the blocking-plate-side labyrinth
member 73 and the nozzle-side labyrinth member 74.
[0178] The nozzle-side labyrinth member 74 is fixed to a nozzle
holding portion 78 held in a non-rotational state. The nozzle
holding portion 78 is moved upward/downward by a nozzle elevator
driving mechanism 79.
[0179] On the other hand, in order to move the blocking plate 60
upward/downward, a blocking plate hand 81 and a blocking plate
elevator driving mechanism 82 that moves the blocking plate hand 81
upward/downward are provided. The blocking plate hand 81 is
provided with a through-hole for the flange pipe 71 to penetrate
through, and a plurality of hand pins 83 that engage with a
plurality of through-holes 72a made in the peripheral portion of
the blocking plate flange 72, respectively.
[0180] According to this arrangement, by moving the blocking plate
hand 81 upward/downward by the blocking plate elevator driving
mechanism 82, the blocking plate 60 is allowed to retract above the
spin chuck 1 or to engage with the receive pins 61 provided to the
spin chuck 1.
[0181] According to this substrate periphery processing apparatus,
the blocking plate 60 receives a rotational force from the spin
chuck 1 and thereby rotates together with the spin chuck 1. It
should be appreciated, however, that the processing to be applied
to the peripheral portion of the upper surface of the wafer W is
substantially the same as in the first embodiment described
above.
[0182] In other words, the etching liquid supplied from the central
axis nozzle 5 toward the center of the lower surface of the wafer W
is forced outwards in the direction of the radius by a centrifugal
force, and reaches the peripheral portion of the upper surface of
the wafer W by coming around the peripheral end surface. The
etching liquid then forms a liquid film in a gap between the
peripheral portion of the upper surface of the wafer W and the
wafer-opposing surface 67 of the annular portion 65. The liquid
film thus formed comes in contact with the wafer-opposing surface
67, and further comes in contact with the guide edge portion 68.
The etching processing can thus take place in the peripheral
portion of the upper surface of the wafer W while the etching
processing width is controlled with accuracy.
[0183] On the other hand, the process gas supplied from the process
gas supply pipe 77 to the space above the wafer W collides with the
inner wall surface 69 of the annular groove 66 formed inside the
annular portion 65, which gives rise to an airflow heading downward
along the inner wall surface 69. It is thus possible to prevent the
etching liquid from entering an inner region of the wafer W in a
reliable manner.
[0184] Also, because the degassing paths 80 that allow a
communication between the internal space of the annular groove 66
and the external space of the blocking plate 60 are formed in the
annular portion 65, a large pressure difference will not be
produced between the inside and the outside of the annular portion
65. Therefore, there is no possibility that breaking occurs
anywhere in the liquid film of the etching liquid formed on the
peripheral portion of the upper surface of the wafer W.
[0185] FIG. 4 shows a cross section of a substrate periphery
processing apparatus according to a third embodiment of the
invention. In FIG. 4, components furnished with like functions as
those shown in FIG. 1 are labeled with the like reference numerals
with respect to FIG. 1.
[0186] In this embodiment, the top lid portion 31 of the blocking
plate 10 is provided with a liquid-receiving groove 85 having a
funnel-shaped cross section in the peripheral portion along the
entire circumference above the annular member 32. Openings
(discharge ports) are provided in the bottom portion of the
liquid-receiving groove 85 in the circumferential direction at
adequate intervals, and the openings communicate respectively with
a plurality of processing liquid supply paths 86 made in the
annular member 32 along the vertical direction. In short, a
plurality of the processing liquid supply paths 86 are provided
along the circumferential direction of the annular member 32, for
example, at equiangular intervals (for example, 72 of them at 50
intervals).
[0187] Each processing liquid supply path 86 includes a dispense
port that opens in the wafer-opposing surface 45 (for example, a
circular hole having a diameter of 0.5 mm), and supplies the
etching liquid to a space between the wafer-opposing surface 45 and
the peripheral portion of the upper surface of the wafer W in a
direction perpendicular or perpendicular to the upper surface of
the wafer W. A liquid film of the etching liquid that comes in
contact with the wafer-opposing surface 45 is thereby formed in the
peripheral portion of the upper surface of the wafer W.
[0188] The etching liquid is supplied to the liquid-receiving
groove 85 continuously or intermittently from a movable nozzle 88
provided in a displaceable manner in a direction to come in close
proximity to or move away from the rotational axis line of the
blocking plate 10. It is arranged in such a manner that the etching
liquid is supplied to the movable nozzle 88 from the etching liquid
supply source via an etching liquid supply valve 89. It should be
noted that, in this embodiment too, the etching liquid is supplied
to the lower surface of the wafer W from the central axis nozzle 5
below the wafer W, and therefore the etching processing is applied
to the lower surface of the wafer W.
[0189] According to the foregoing arrangement, the etching
processing to the peripheral portion of the wafer W, the deionized
water rinsing processing to the upper and lower surfaces of the
wafer W, and the drying processing to the upper and lower surfaces
of the wafer W can be performed in the same manner as the first
embodiment described above.
[0190] It should be noted, however, that according to the
arrangement of this embodiment, a supply of the etching liquid from
the central axis nozzle 5 pointed to the lower side of the wafer W
is not necessarily required in the step of applying the etching
processing to the peripheral portion of the upper surface of the
wafer W. In other words, in a case where the etching processing
need not to be applied to the lower surface of the wafer W, a
supply of the etching liquid from the central axis nozzle 5 can be
omitted.
[0191] When a supply of the etching liquid from the central axis
nozzle 5 is omitted, it is not necessary to transfer the etching
liquid to the peripheral end surface of the wafer W by a
centrifugal force, either. It is therefore sufficient to rotate the
spin chuck 1 and the blocking plate 10 at a lower rotational speed
than in the first embodiment.
[0192] Further, according to the arrangement of this embodiment,
the etching processing can be applied to the peripheral portion of
the wafer W while the spin chuck 1 is substantially held at
rest.
[0193] In short, the blocking plate 10 is rotated at a low speed
while the spin chuck 1 is stopped rotating. Under these conditions,
the etching liquid is supplied along the entire circumference of
the liquid-receiving groove 85 from the movable nozzle 88, then the
etching liquid is supplied to the peripheral portion of the upper
surface of the wafer W through the processing liquid supply paths
86. A supply of the etching liquid is stopped by closing the valve
89 after a necessary quantity of the etching liquid is supplied,
and the blocking plate 10 is stopped rotating. A mound of the
etching liquid is thus placed on the surface of the peripheral
portion along the entire circumference. By maintaining this liquid
mounding state for a predetermined time (for example, five to forty
seconds), selective etching processing can be applied to the
peripheral portion of the wafer W. The liquid mounding processing
as described above can reduce a quantity of consumed etching liquid
markedly. A mound of the etching liquid placed in this manner forms
a liquid film that comes in contact with the wafer-opposing surface
45 of the annular member 32. The guide edge portion 46 limits the
movement of the liquid film toward the inside of the wafer W in a
reliable manner.
[0194] Even in the case of the liquid mounding processing, the
etching liquid may be supplied to the liquid-receiving groove 85
from the movable nozzle 88 continuously or intermittently. Also,
the spin chuck 1 may be rotated at a speed low enough to prevent a
mound of the etching liquid placed on the peripheral portion of the
wafer W from being discharged to the outside of the wafer W by a
centrifugal force.
[0195] In the above description, the etching liquid is supplied to
the wafer W while the blocking plate 10 is rotated at a low speed
whereas the spin chuck 1 is stopped rotating. However, besides this
arrangement, the etching liquid may be supplied to the wafer W
while both the spin chuck 1 and the blocking plate 10 are rotated
at different low speeds, or while the spin chuck 1 is rotated at a
low speed whereas the blocking plate 10 is stopped rotating.
Alternatively, the etching liquid may be supplied to the wafer W by
moving the movable nozzle 88 along the entire circumference of the
liquid-receiving groove 85 while both the spin chuck 1 and the
blocking plate 10 are stopped rotating. In any case, a mound of the
etching liquid can be placed on the peripheral portion of the upper
surface of the wafer W along the entire circumference.
[0196] "The low speed" of the spin chuck 1 and the blocking plate
10 referred to herein means a rotational speed low enough to
prevent the etching liquid on the peripheral portion of the upper
surface of the wafer W from spilling outwards, and for example, a
rotational speed at or below 60 rpm is preferable.
[0197] As has been described, by supplying the etching liquid to
the peripheral portion of the upper surface of the wafer W while
the wafer-opposing surface 45 of the annular member 32 is brought
in close proximity to the peripheral portion of the upper surface
of the wafer W, the etching liquid is maintained stably in a gap
between the wafer-opposing surface 45 and the peripheral portion of
the upper surface of the wafer W. It is thus possible to perform
the etching processing in a satisfactory manner without consuming a
large quantity of the etching liquid.
[0198] It should be appreciated that after the peripheral portion
of the upper surface of the wafer W is processed by placing a mound
of the etching liquid thereon, the rinsing of the wafer W with
water followed by the drying processing is performed in the same
manner as was discussed in the first embodiment above.
[0199] FIG. 5(a) through FIG. 5(g) show partially enlarged cross
sections used to explain various configurations of the annular
member that controls a liquid film of the etching liquid at the
peripheral portion of the surface of the wafer W. The example of
FIG. 5(f) is the same as the arrangement of the first embodiment
shown in FIG. 1 and FIG. 2. The example of FIG. 5(d) is the same as
the arrangement of the second embodiment shown in FIG. 3. In the
drawings, capital letter E indicates the etching liquid.
[0200] FIG. 5(a) shows the most basic configuration of the annular
member, and it shows an annular member including the inner
periphery with a diameter smaller than the diameter of the wafer W,
and the wafer-opposing surface 45 opposing the peripheral portion
of the upper surface of the wafer W. No guide edge portion is
provided to the inner periphery of the wafer-opposing surface 45.
However, even in the absence of the guide edge portion, a liquid
film of the etching liquid E is limited at a position slightly
inside the wall surface 47 of the annular member, and the liquid
film is thereby controlled so as not to enter an inner region of
the wafer W. Also, the wafer-opposing surface 45 comes in contact
with the liquid film of the etching liquid E and produces a liquid
sealing state.
[0201] The example of the arrangement shown in FIG. 5(b) is
achieved by developing the arrangement of FIG. 5(a), in which a lid
portion 90 is provided integrally. By providing the lid portion 90,
it is possible to prevent droplets in the surroundings from passing
through the annular member to be scattered in the central region
(device-forming region) of the wafer W or mist from adhering to the
central portion.
[0202] The arrangement shown in FIG. 5(c) is achieved by further
developing the configuration of FIG. 5(b), in which the annular
groove 51 is provided adjacently inside the inner wall surface 47
of the annular member. The arrangement in the configuration shown
in FIG. 5(d) is achieved by further developing the arrangement of
FIG. 5(c), in which the guide edge portion 46 is provided so as to
control the liquid film of the etching liquid E not to enter an
inner region of the wafer W in a reliable manner.
[0203] The configuration shown in FIG. 5(e) is achieved by further
developing the configuration of FIG. 5(d), in which a gas is
supplied to the inner wall surface 47 of the annular member, so
that the gas is blown out from the gas nozzle 35 to the surface of
the wafer W along the inner wall surface 47. According to this
arrangement, because the interior of the annular member can be
maintained at a positive pressure, a liquid film of the etching
liquid E can be controlled with high accuracy.
[0204] Further, the arrangement of FIG. 5(f) is achieved by
modifying the arrangement of FIG. 5(e), in which a counter-bore
portion is formed at the outer periphery of the lower surface of
the central plate 33 to form the annular groove 51 between the
center plate 33 and the inner wall surface 47 of the annular
member. When the configuration of FIG. 5(e) is compared with the
configuration of FIG. 5(f), because the annular groove is not
provided at a position adjacently inside the inner wall surface 47
of the annular member in the configuration of FIG. 5(e), it can be
the that the arrangement of FIG. 5(f) excels in the control ability
as to a liquid film of the etching liquid E.
[0205] As shown in FIG. 5(g), the outer periphery of the
wafer-opposing surface 45 of the annular member may be located
outside the outer periphery of the wafer W. The wafer-opposing
surface 45 may be formed to extend outwards beyond the outer
periphery of the wafer W. By adopting such an arrangement, it is
possible to trap the etching liquid E supplied from the lower
surface of the wafer W in a satisfactory manner on the peripheral
end surface of the wafer W. It is thus possible to form a
satisfactory liquid film on the peripheral portion of the upper
surface of the wafer W in a reliable manner.
[0206] FIG. 6(a) through FIG. 6(c) are cross sections showing
modifications as to the shape of the inner wall surface of the
annular member. In the example shown in FIG. 6(a), the inner wall
surface 47 forms an inclined plane (conical plane) heading toward
the inside of the wafer W as it moves away from the upper surface
of the wafer W.
[0207] In the example of FIG. 6(b), the inner wall surface 47 forms
an inclined plane (inverted conical plane) heading toward the
outside of the wafer W as it moves away from the upper surface of
the wafer W.
[0208] According to the arrangement of FIG. 6(c), the inner wall
surface 47 forms a bent plane including an upright rising surface
47a that rises upright or nearly upright from the upper surface of
the wafer W, and an inclined plane 47b that continues from the
upper edge of the upright rising surface 47a while heading toward
the inside of the wafer W as it moves away from the upper surface
of the wafer W.
[0209] By forming the inner wall surface 47 of the annular member
as the inclined plane in the configuration of FIG. 6(a), the
etching liquid E heading toward the inside of the wafer W tries to
move away from the surface of the wafer W along the inclined inner
wall surface 47. However, such a movement of the etching liquid E
along the inner wall surface 47 is prevented by gravity. When the
annular member is rotating, in particular, the movement of the
etching liquid E along the inner wall surface 47 is prevented by a
centrifugal force. This prevents the etching liquid E from reaching
an inner side of the wafer W in a reliable manner by controlling a
liquid film of the etching liquid E to be formed under the
wafer-opposing surface in a reliable manner.
[0210] FIG. 7(a) through FIG. 7(c) are cross sections showing
modifications as to the shape of the wafer-opposing surface of the
annular member. In the example of FIG. 7(a), the wafer-opposing
surface 45 forms an inclined plane (inverted conical plane) that
comes in close proximity to the upper surface of the wafer W as it
heads toward the inside of the wafer W.
[0211] Also, in the example of FIG. 7(b), the wafer-opposing
surface 45 forms a curved plane that curves so as to come in close
proximity to the upper surface of the wafer W as it heads toward
the inside of the wafer W.
[0212] Further, in the example of FIG. 7(c), the wafer-opposing
surface 45 forms a bent plane including an outer-periphery-side
parallel portion 45a that is provided on the outer periphery side
and substantially parallel to the upper surface of the wafer W, an
inner-periphery-side parallel portion 45c that is provided inside
the outer-periphery-side parallel portion 45a and comes in closer
proximity to the upper surface of the wafer W than the
outer-periphery-side parallel portion 45a while being parallel to
the upper surface of the wafer W, and an inclined portion 45b that
couples the inner-periphery-side parallel portion 45c to the
outer-periphery-side parallel portion 45a. The inclined portion 45b
forms an inclined plane (inverted conical plane) that comes in
close proximity to the wafer W as it heads toward the inside of the
wafer W.
[0213] In any of the arrangements of FIG. 7(a), FIG. 7(b), and FIG.
7(c), a distance between the wafer-opposing surface 45 and the
upper surface of the wafer W becomes shorter in the inner side of
the wafer W. By forming the wafer-opposing surface 45 in any of the
shapes as above, a liquid film of the etching liquid E can be
controlled in a more satisfactory manner, which makes it possible
to prevent the etching liquid E from entering an inner region of
the wafer W in a reliable manner. Because the etching liquid can be
more readily introduced into a space between the wafer-opposing
surface 45 and the upper surface of the wafer W, a liquid sealing
state can be produced in a satisfactory manner.
[0214] FIG. 8(a) through FIG. 8(e) are cross sections showing
modifications of the guide edge portion 46 provided to the
wafer-opposing surface 45 of the annular member. The example of
FIG. 8(a) is a case where the side surface of the guide edge
portion 46 on the inner side of the wafer W is formed as an
inclined plane (conical plane) heading toward the inside of the
wafer W as it moves away from the surface of the wafer W, while the
side surface of the guide edge portion 46 on the outer side of the
wafer W is formed as an inclined plane (inverted conical plane)
heading toward the outside of the wafer W as it moves away from the
surface of the wafer W.
[0215] The example of FIG. 8(b) is a case where a convex strip
having a nearly rectangular cross section is provided as the cross
section of the guide edge portion 46, and a cylindrical surface
nearly perpendicular to the upper surface of the wafer W is
provided as the etching liquid limiting surface 46a.
[0216] The example of FIG. 8(c) is a case where the etching liquid
limiting surface 46a is formed not as an inclined plane (conical
plane) but as a curved plane that forms a rounded plane in cross
section.
[0217] Further, the example of FIG. 8(d) is a case where a
wafer-opposing portion 46b that opposes the wafer W is provided to
the lower end of the guide edge portion 46 by shifting the etching
liquid limiting surface 46a toward the outside of the wafer W, and
a liquid-releasing path 95 that opens in the wafer-opposing portion
46b is made in the annular member. The liquid-releasing path 95
opens also in the outer wall surface 48 of the annular member.
[0218] For example, when the annular member is rotated together
with the blocking plate 10, a centrifugal force acts on the etching
liquid E inside the liquid-releasing path 95, and the etching
liquid E is pumped up from the wafer-opposing portion 46b of the
guide edge portion 46, passes through the liquid-releasing path 95,
and is discharged to the outside of the annular member. It is thus
possible to prevent the etching liquid E from entering inside the
annular member in a more reliable manner.
[0219] In the example of FIG. 8(e), the liquid-releasing path 95
merges with the degassing paths 49. In other words, when the
process gas is supplied to the inside of the annular member, the
process gas is discharged to the outside of the annular member by
passing through the degassing paths 49. In this instance, the
ejector effect is induced, by which the etching liquid E is pumped
up from the wafer-opposing portion 46b and discharged to the
outside.
[0220] FIG. 9(a) through FIG. 9(h) are schematic cross sections
showing examples of a configuration to supply the etching liquid E
to the peripheral portion of the upper surface of the wafer W. FIG.
9(a) shows the example shown in FIG. 1 and FIG. 3. To be more
specific, the etching liquid E is supplied toward the center of the
lower surface of the wafer W, and the etching liquid E is guided
toward the outside of the wafer W by a centrifugal force, and
reaches the peripheral portion of the upper surface of the wafer W
by coming around the peripheral end surface.
[0221] The example of FIG. 9(b) shows a case where the etching
liquid E is provided toward the peripheral portion of the lower
surface of the wafer W from a nozzle 100 provided below the wafer W
(that is, below the spin chuck 1). In this case also, the etching
liquid E receiving a centrifugal force on the lower surface of the
wafer W comes around the peripheral end surface of the wafer W and
reaches the peripheral portion of the upper surface. The example of
FIG. 9(b) shows a case where the etching liquid E is discharged
through the discharge port of the nozzle 100 at an inclined angle
heading toward the outside of the wafer W (for example, 10 to 45
degrees, and preferably 30 degrees) from below the wafer W, and is
incident on the lower surface of the wafer W at the same angle.
[0222] The example of FIG. 9(c) shows a case where the etching
liquid E is supplied from above to the upper surface of the wafer W
outside the annular member 32 from a nozzle 101 provided above the
wafer W. In this case, it is preferable that the annular member 32
is arranged to have an outer wall surface 48 well inside the
peripheral end surface of the wafer W. Even when arranged in this
manner, it is still possible to prevent a liquid film of the
etching liquid E from entering the central region of the wafer W by
the annular member 32.
[0223] Although the nozzle 101 is provided just above the
peripheral region of the wafer, such a nozzle may be located
outside of the area just above the wafer to supply the etching
liquid E in the inclined direction with respect to the surface of
the wafer W.
[0224] The example of FIG. 9(d) is a case where the etching liquid
E is supplied from a nozzle 102 toward the outer wall surface 48 of
the annular member 32. In this case, the etching liquid E thus
supplied is then supplied to the peripheral portion of the upper
surface of the wafer W by flowing down on the outer wall surface 48
of the annular member 32. In order to introduce the etching liquid
E flowing down on the outer wall surface 48 to the peripheral
portion of the wafer W in a satisfactory manner, it is preferable
to form the wafer-opposing surface 45 as an inclined plane that
comes in close proximity to the upper surface of the wafer W as it
heads toward the inside the wafer W.
[0225] The example of FIG. 9(e) is a case where an etching liquid
supply path 105 is provided within the blocking plate 10 to allow a
communication between the etching liquid supply path 105 and a
discharge port that opens in the wafer-opposing surface 45 of the
annular member 32. This arrangement makes it possible to supply the
etching liquid E directly to the peripheral portion of the upper
surface of the wafer W. In the case of the FIG. 9(e), the etching
liquid supply path 105 is arranged in such a manner that it is
inclined to head outwards as it nears the wafer-opposing surface 45
within the annular member 32, so that the etching liquid E is
supplied to the peripheral portion of the upper surface of the
wafer W in a direction inclined toward the outside of the wafer
W.
[0226] The example of FIG. 9(f) is the same as the arrangement
shown in FIG. 4. That is, a liquid-receiving portion 107 is
provided above the annular member 32 to receive the etching liquid
E, and the etching liquid is supplied to the liquid-receiving
portion 107 from an etching liquid supply nozzle 108 continuously
or intermittently. The liquid-receiving portion 107 communicates
with a discharge port that opens in the wafer-opposing surface
45.
[0227] The example of FIG. 9(g) shows a case where a
liquid-receiving portion 110 that opens in the outer wall surface
48 of the annular member 32 is provided, and the etching liquid E
from a nozzle 111 is supplied to the liquid-receiving portion 110
from the side. The liquid-receiving portion 110 communicates with a
liquid supply path 112 formed within the annular member 32, and the
liquid supply path 112 opens in the wafer-opposing surface 45.
[0228] The example of FIG. 9(h) shows a case where an etching
liquid supply path 115 that opens in the wafer-opposing surface 45
and a liquid discharge path 116 that also opens in the
wafer-opposing surface 45 are provided within the annular member
32. According to this arrangement, the etching liquid E is supplied
through the etching liquid supply path 115 to a space between the
wafer-opposing surface 45 and the peripheral portion of the upper
surface of the wafer W, while the etching liquid E is discharged
through the liquid discharge path 116, which makes it possible to
apply the etching processing to the peripheral portion of the upper
surface of the wafer W while circulating the etching liquid E.
According to this arrangement, because new etching liquid E is
constantly supplied to the peripheral portion of the upper surface
of the wafer W, the etching processing speed can be improved.
[0229] When the etching processing is performed in portions where a
mound of the etching liquid E is placed in the peripheral portion
of the upper surface of the wafer W while the wafer W is held at
rest, it is preferable to supply the etching liquid E by any of the
configurations shown in FIG. 9(c), FIG. 9(d), FIG. 9(e), FIG. 9(f),
FIG. 9(g), and FIG. 9(h).
[0230] When the processing is performed while the wafer W is
rotating in any of the configurations shown in FIG. 9(a), FIG.
9(b), FIG. 9(c), FIG. 9(d), FIG. 9(e), FIG. 9(f), FIG. 9(g), and
FIG. 9(h), by supplying the etching liquid E toward the center of
the lower surface of the wafer W concurrently as indicated by a
chain double-dashed line, the processing to the lower surface of
the wafer W can be performed in parallel.
[0231] In the embodiments described above, the gas nozzle 35
includes a continuous slit opening of a circular shape along the
entire circumference. However, the gas nozzle 35 may include a
plurality of gas discharge ports made in the circumferential
direction at intervals (for example at equiangular intervals) about
the rotational axis of the wafer W. The discharge ports of the gas
may be a circular hole or an arc-shaped oblong hole.
[0232] Also, in the embodiments described above, it is arranged in
such a manner that the processing liquid will not be supplied to
the central portion of the upper surface of the wafer W when the
peripheral portion of the upper surface of the wafer W is
processed. However, the central region of the wafer W may be
covered with deionized water by opening the deionized water supply
valve 15 while the peripheral portion of the upper surface of the
wafer W is being processed, so that the central region is protected
from the etching liquid. In order to protect the central region of
the wafer W, etching protection liquid, such as carbonated water,
hydrogenated water, returned water, ionized water, and magnetized
water, can be used instead of deionized water.
[0233] It should be noted, however, that the etching protection
liquid supplied to the central region of the wafer W gets mixed
with and dilutes the etching liquid on the peripheral portion of
the wafer W, and it is therefore preferable not to use the etching
protection liquid when a reduction of a quantity of consumed
etching liquid is desired.
[0234] In the embodiments described above, the spin chuck 1
arranged to clamp the peripheral end surface of the wafer W was
explained by way of example. However, a vacuum chuck that holds the
wafer W by attracting the lower surface, and a roller chuck that
rotates the wafer W by rotating while abutting on the end surface
of the wafer W may be adopted. When the wafer W does not have to be
rotated, a holding mechanism that moves the wafer W only spatially,
or a fixed-type holding mechanism that holds the lower surface of
the wafer W with a plurality of pins fixed to the ground surface
may be adopted.
[0235] Also, in the embodiments described above, an explanation has
been given to the processing of a semiconductor wafer, which is a
substrate of a circular shape, by way of example. However, in the
case of adopting the process of performing the processing by
placing a mound of the etching liquid on the substrate, in
particular, the invention is applicable to a rectangular substrate,
such as a glass substrate for a liquid crystal display.
[0236] FIG. 10 is a view schematically showing an arrangement of a
substrate periphery processing apparatus according to a fourth
embodiment of the invention. The substrate periphery processing
apparatus is an apparatus to perform processing that removes a
metal thin film (for example, copper thin film) C formed on the
device-forming surface and the peripheral surface of the wafer W,
used as an example of a substrate, from unwanted portions, that is,
the peripheral portion of the device-forming surface and the
peripheral surface. The substrate periphery processing apparatus is
provided with a spin chuck 501 that rotates while holding the wafer
W almost horizontally, a blocking member 502 placed in close
proximity to the upper surface of the wafer W held by the spin
chuck 501, and a nozzle 503 used to supply the etching liquid to
the upper surface 523 of the blocking member 502.
[0237] The spin chuck 501 includes, for example, a spin shaft 511
placed almost vertically, and an attraction base 512 fixed to the
top end of the spin shaft 511. The spin chuck 501 is arranged so as
to hold the wafer W in a nearly horizontal posture by
vacuum-attracting a device non-forming surface (lower surface) of
the wafer W by exhausting air in an air intake path formed within
the attraction base 512 while the wafer W is placed on the
attraction base 512 with the device-forming surface facing upward.
A rotational driving mechanism 513 including a motor or the like is
coupled to the spin shaft 511, and by inputting a rotational force
into the spin shaft 511 from the rotational driving mechanism 513
while the wafer W is being held by the attraction base 512 through
attraction, the wafer W is rotated about the vertical axis line
(the central axis line of the spin shaft 511) passing through the
center or nearly the center of the wafer W.
[0238] The blocking member 502 includes a lower portion 502A shaped
like a circular plate having a diameter slightly smaller than the
diameter of the wafer W, and an upper portion 502B shaped like a
cone having one surface of the lower portion 502A as the bottom
surface. The other surface 521 of the lower portion 502A is
provided oppositely in parallel with the upper surface of the wafer
W held by the spin chuck 501. In other words, the blocking member
502 includes a lower surface 521 of a circular shape slightly
smaller than the outside shape of the wafer W, a side surface 522
rising upright or nearly upright from the periphery of the lower
surface 521, and an upper surface 523 of a conical shape inclined
to approach the axis line passing through the center of the lower
surface 521 as it heads upward from the top end edge of the side
surface 522. The blocking member 502 is thus formed in the shape of
a rotational body using the axis line passing through the center of
the lower surface 521 as the central axis line. The blocking member
502 is provided in such a manner that its central axis line agrees
with the central axis line of the spin shaft 511.
[0239] Inside the blocking member 502 is formed a nitrogen gas
supply path 524 along the central axis line of the blocking member
502. A nitrogen gas is supplied to the nitrogen gas supply path 524
from a nitrogen gas supply source outside of the drawing. The
nitrogen gas supply path 524 communicates with an opening 525 made
in the lower surface 521 of the blocking member 502 at the center,
and a nitrogen gas supplied to the nitrogen gas supply path 524 is
discharged through the opening 525 toward the central portion of
the upper surface of the wafer W held by the spin chuck 501.
[0240] A hydrophobic member 526 formed to have a trapezoidal cross
section is embedded in the lower portion 502A of the blocking
member 502 from below, and the lower surface of the hydrophobic
member 526 forms the lower surface 521 of the blocking member 502.
The hydrophobic member 526 is not exposed to the side surface 522
of the blocking member 502. The surface (at least the lower
surface) of the hydrophobic member 526 is coated with fluororesin,
which makes the lower surface 521 of the blocking member 502 as a
hydrophobic surface having a hydrophobic property. On the other
hand, the side surface 522 and the upper surface 523 of the
blocking member 502 are made as hydrophilic surfaces having a
hydrophilic property by increasing a surface roughness through
sandblast treatment.
[0241] Herein, the lower surface 521 as the hydrophobic surface is
set to have 60 degrees or greater as an angle of contact (when a
droplet of deionized water adheres on a given surface, an angle
produced between the droplet-adhering surface and the surface of
the droplet) between the surface 521 and a droplet of deionized
water. The side surface 522 and the upper surface 523 as the
hydrophilic surfaces are set to have 10 degrees or less as an angle
of contact between these surfaces and a droplet of deionized
water.
[0242] Before the processing to the wafer W is started, the
blocking member 502 is retracted far above so as not to interfere
with the transportation of the wafer W. Then, when the wafer W is
transported by an unillustrated transporting robot and delivered to
the spin chuck 501, the blocking member 502 is lowered to a
position at which the lower surface 521 comes in close proximity to
the upper surface of the wafer W while securing a predetermined
interval.
[0243] Subsequently, the spin chuck 501 (that is, the wafer W) is
rotated at a predetermined rotational speed, and a nitrogen gas is
supplied toward the upper surface of the rotating wafer W through
the opening 525 in the lower surface 521 of the blocking member
502. Because a space between the wafer W and the blocking member
502 is filled with the nitrogen gas thus supplied, it is possible
to prevent the etching liquid and an atmosphere containing the
etching liquid from entering this space from outside. This prevents
the metal thin film C formed on the central portion (device-forming
region) of the upper surface of the wafer W from undergoing
unwanted etching processing.
[0244] Also, the etching liquid is supplied to the upper surface
523 of the blocking member 502 from the nozzle 503. The nozzle 503
is placed on the central axis line of the blocking member 502, and
the etching liquid from the nozzle 503 is supplied uniformly in the
vicinity of the apex of the upper surface 523 of the blocking
member 502 (the cone-shaped region having the central axis line of
the blocking member 502 at the center).
[0245] Because the upper surface 523 and the side surface 522 of
the blocking member 502 are hydrophilic surfaces, the etching
liquid supplied to the upper surface 523 of the blocking member 502
spreads and flows downward along the upper surface 523, and flows
on the side surface 522 further downward. Because the lower surface
521 of the blocking member 502 is a hydrophobic surface, the
etching liquid reaching the lower end edge of the side surface 522
does not come around to the lower surface 521, and instead it flows
continuously and vertically downward from the entire circumference
of the lower end edge of the side surface 522. Thus, as shown in
FIG. 11, the etching liquid flowing down from the blocking member
502 forms a liquid wall having a cylindrical surface 504 in contact
with the side surface 522 of the blocking member 502, while being
supplied to a region A1 (region to be etched) outside an
intersection line of the upper surface of the wafer W and the
cylindrical surface 504. The etching liquid supplied to the upper
surface of the wafer W is then forced toward the periphery of the
wafer W by a centrifugal force induced from rotations of the wafer
W, and flows down on the peripheral surface (end surface) of the
wafer W from the periphery of the wafer W. The unwanted metal thin
film formed on the region A1 of the upper surface and on the entire
peripheral surface of the wafer W can be thus removed.
[0246] As has been described, according to this embodiment, the
etching liquid to be supplied to the peripheral portion of the
upper surface of the wafer W is supplied to the upper surface 523
of the blocking member 502 from the nozzle 503 first, then flows on
the upper surface 523 and the side surface 522 of the blocking
member 502, and flows downward to the peripheral portion of the
upper surface of the wafer W while forming a liquid wall having the
cylindrical surface 504 that conforms to the side surface 522 of
the blocking member 502. Because the upper surface 523 and the side
surface 522 of the blocking member 502 are hydrophilic surfaces
while the lower surface 521 is a hydrophobic surface, the etching
liquid on the upper surface 523 or the side surface 522 of the
blocking member 502 neither scatters outward nor comes around to
the lower surface 521 of the blocking member 502 to fall on a
region B1 (region not to be etched) where the metal thin film C
needs to be left. The cylindrical surface 504 of the liquid wall
formed by the etching liquid thereby intersects with the upper
surface of the wafer W on a specific line. This eliminates variance
in width (etching width) of the region A1 where the metal thin film
C on the upper surface of the wafer W needs to be removed, and
therefore makes it possible to control the etching width more
accurately than a conventional apparatus. Further, it is also
possible to prevent the etching liquid from entering the region B1
where the metal thin film C needs to be left.
[0247] In this embodiment, the blocking member 502 is held at rest
while the etching liquid is supplied to the wafer W. However, a
rotational driving mechanism may be provided in association with
the blocking member 502, so that the rotational driving mechanism
rotates the blocking member 502, for example, about the central
axis line of the blocking member 502, that is, coaxially with the
rotational axis of the wafer W. By rotating the blocking member
502, a quantity of the flowing-down etching liquid can be made
equal or nearly equal at the lower end edge of the blocking member
502 along the entire circumference. Even when the blocking member
502 is rotated, because the upper surface 523 and the side surface
522 of the blocking member 502 are hydrophilic and the lower
surface 521 is hydrophobic, the etching liquid flowing down from
the blocking member 502 flows downward to the peripheral portion of
the upper surface of the wafer W while forming the liquid wall
having the cylindrical surface 504 that conforms to the side
surface 522.
[0248] Also, the wafer W is kept rotated while the etching liquid
is supplied to the wafer W in this embodiment. However, the
processing may be performed while the wafer W is held at rest. Even
in this case, it is possible to prevent the supplied etching liquid
from entering the central portion of the wafer Was long as a gas
(nitrogen gas) is supplied through the opening 525 made in the
lower surface 521 at the center.
[0249] Further, the blocking member 502 includes the lower surface
521 of a circular shape slightly smaller than the outer shape of
the wafer W in this embodiment. This is because the region (region
not to be etched) B1 where the metal thin film C on the upper
surface of the wafer W needs to be left is set in a region of a
circular shape at the central portion of the wafer W, while the
region (region to be etched) A1 where the metal thin film needs to
be removed is set in an annular region surrounding the region not
to be etched. That is to say, it is sufficient that the blocking
member 502 includes a shape such that corresponds to the boundary
dividing the region to be etched and the region not to be etched,
at the lower end edge.
[0250] When the processing is performed while the wafer W is held
at rest on the spin chuck 501 and the blocking member 502 is also
held at rest, in order to remove the metal thin film formed on the
upper surface of the wafer W through etching from an annular region
in the peripheral portion and a region held by the hand H of the
transporting robot (a region A2 to be etched), as shown in FIG. 12,
for example, the boundary dividing the region A2 to be etched and a
region B2 not to be etched may be set, and the lower surface (lower
end edge) of a blocking member 505 may be formed into a shape
corresponding to the boundary thus set. It should be noted that the
lower surface of the blocking member 505 is a hydrophobic surface
and the upper surface and the side surface of the blocking member
505 are hydrophilic surfaces in this case, too. In addition, in
order to prevent the etching liquid from entering the region B2 not
to be etched, a gas (nitrogen gas) is supplied through an opening
535 made in the lower surface (surface opposing the wafer W) of the
blocking member 505 at the center.
[0251] Also, as shown in FIG. 13, a boundary dividing a region A3
to be etched and a region B3 not to be etched may be set linearly,
so that a blocking member 506 includes a rectangular lower surface
(hydrophobic surface), a side surface (hydrophilic surface) rising
upright or nearly upright from the periphery of the lower surface,
and a planar upper surface (hydrophilic surface) inclined downward
as it nears the boundary.
[0252] Additionally, in order to prevent the etching liquid from
entering the region B3 not to be etched, a gas (nitrogen gas) is
supplied through a plurality of openings 545 made in the lower
surface (surface opposing the wafer W) of the blocking member 506.
The plurality of openings 545 are provided along the linear
boundary dividing the region A3 to be etched and the region B3 not
to be etched. Further, it is preferable that a direction in which
the gas is blown out through the plurality of openings 545 is
tilted at a specific angle, so that an airflow is developed above
the upper surface of the wafer W in a direction heading to the
region A3 to be etched from the region B3 not to be etched.
[0253] Further, according to the embodiment shown in FIG. 13, the
wafer W may be rotated about the rotational axis that intersects at
right angles with the wafer W by a substrate holding mechanism that
holds the wafer W. When arranged in this manner, the region A3 to
be etched can be an annular region in the peripheral portion of the
wafer W. By setting the rotational axis of the wafer W to pass
through the center of the wafer W, it is possible to give a
substantially regular width to the annular region in the region A3
to be etched along the entire circumference of the wafer W.
Alternatively, by setting the rotational axis of the wafer W away
from the center of the wafer W, it is possible to vary the width of
the annular region in the circumferential direction and thereby to
obtain an eccentric annular region as the region A3 to be etched.
When the wafer W is rotated as described above, a circular region
about the rotational axis of the wafer W is obtained as the region
B3 not to be etched.
[0254] Further, a nitrogen gas is supplied to a space between the
wafer W and the blocking member 502 in the embodiments above.
However, a gas to be supplied is not limited to a nitrogen gas, and
other inert gases, such as a helium gas and argon gas, may be
supplied as well.
[0255] Also, in the embodiments above, side surfaces are provided
to the blocking members 502, 505 and 506. However, the blocking
member may omit the side surface. In other words, the upper surface
and the lower surface of the blocking member may intersect directly
on the end edge of the blocking member. It should be noted,
however, that when accuracy as to the shape of the region to be
etched needs to be improved, it is preferable to provide a side
surface, in particular, a vertical side surface, as was described
in the embodiments above.
[0256] The embodiments above described the processing that removes
an unwanted metal thin film formed on the wafer W with the use of
the etching liquid as an example of the processing applied to the
region subject to processing of the wafer W. However, the
processing applied to the region subject to processing of the wafer
W may be peripheral-portion rinsing processing that rinses the
peripheral portion of the wafer W with rinsing liquid, or
alternatively, it may be resist removing processing that removes an
unwanted resist film formed on the wafer W with the use of resist
removing liquid.
[0257] The substrate subject to processing is not limited to the
wafer W, and it may be substrates of other kinds, including a glass
substrate for a liquid crystal display, a glass substrate for a
plasma display panel, a glass substrate for a photomask, etc.
[0258] FIG. 14 is a view schematically showing an arrangement of a
substrate processing apparatus according to a seventh embodiment of
the invention. The substrate processing apparatus is an apparatus
that removes an unwanted metal thin film formed on the peripheral
portion of the device-forming surface, the back surface, and the
peripheral surface (end surface) of the wafer W used as an example
of a substrate. The substrate processing apparatus includes a spin
chuck 601 that rotates while holding the wafer W almost
horizontally, and an opposing member 602 placed oppositely in close
proximity to the upper surface of the wafer W held by the spin
chuck 601.
[0259] The spin chuck 601 includes a motor 611 installed with its
driving shaft aligned along the vertical direction, a spin base 612
attached horizontally to the top end of the driving shaft of the
motor 611, and a plurality of clamping members 613 provided on the
spin base 612. The plurality of clamping members 613 are placed
along the circumference corresponding to the outer shape of the
wafer W, and are able to hold the wafer W almost horizontally by
clamping the wafer W at a plurality of different positions on the
circumferential surface. By driving the motor 611 while the wafer W
is held, the wafer W is rotated about the vertical axis line
passing through the center or nearly the center of the wafer W. The
driving shaft of the motor 611 comprises a hollow shaft, into which
is inserted a back-surface processing nozzle 614 selectively
supplied with the etching liquid and deionized water. The
back-surface processing nozzle 614 includes a dispense port at a
position in close proximity to the center of the lower surface
(back surface) of the wafer W held by the spin chuck 601, and has a
configuration of a central axis nozzle that supplies deionized
water or the etching liquid toward the center of the lower surface
of the wafer W through the dispense port.
[0260] An arm 621 that extends almost horizontally is provided
above the spin chuck 601, and the opposing member 602 is held
rotatably by a holding tubular member 622 hanging from the tip end
portion of the arm 621, and is placed in such a manner that its
rotational axis line agrees with the rotational axis line of the
wafer W. Also, an elevator driving mechanism 623 that moves the
opposing member 602 upward/downward is provided in association with
the arm 621. The opposing member 602 is retracted far above when
the wafer W is transported in or out from the spin chuck 601 so as
not to interfere with the incoming/outgoing transportation of the
wafer W, and is lowered to a position in close proximity to the
upper surface of the wafer W when the wafer W is processed. Also, a
rotational driving mechanism 624 used to rotate the opposing member
602 is provided in association with the arm 621, and the opposing
member 602 is rotated in the same direction as the wafer W when the
wafer W is processed.
[0261] The opposing member 602 is provided with a nitrogen gas
supply path 625 along the rotational axis line, to which a nitrogen
gas is supplied from a nitrogen gas supply source. The nitrogen gas
supply path 625 opens in the lower surface of the opposing member
602 at the center, and a nitrogen gas supplied to the nitrogen gas
supply path 625 is discharged through the opening toward the center
of the upper surface of the wafer W held by the spin chuck 601.
[0262] The opposing member 602 includes a cone portion 627 having a
bottom surface (lower surface) 627A of a circular shape with a
diameter slightly smaller than the diameter of the wafer W and a
conical plane 627B inclined to move away from the rotational axis
line of the opposing member 602 as it heads downward, and a
ring-shaped projection 628 formed in the peripheral portion of the
bottom surface 627A of the cone portion 627 along the entire
circumference. The bottom surface 627A of the cone portion 627
forming the lower surface of the opposing member 602 and the lower
surface 628A of the projection 628 are both nearly parallel to the
upper surface of the wafer W held by the spin chuck 601 and oppose
each other. An outer side surface (outer peripheral surface) 628B
of the projection 628 forming the side surface of the opposing
member 602 is a cylindrical surface along the vertical direction.
The outer side surface 628B and the conical plane 627B of the cone
portion 627 forming the upper surface of the opposing member 602
are connected smoothly, for example, through a rounded plane having
an arc-shaped convex-curved cross section. The opposing member 602
arranged in this manner is formed by applying cutting treatment to
a mold part made of resin, such as vinyl chloride resin and
fluorine-based resin. This provides a surface roughness sufficient
to remain hydrophilic to the conical plane 627B of the cone portion
627 and the lower surface 628A and the outer side surface 628B of
the projection 628.
[0263] An upper surface nozzle 603 is attached to the tip end of
the arm 621, to which the etching liquid is supplied from the
etching liquid supply source. When the etching processing is
performed to the wafer W, the etching liquid is supplied to the
vicinity of the uppermost portion of the conical plane 627B of the
opposing member 602 from the upper surface nozzle 603 while the
wafer W is held by the spin chuck 601 with its device-forming
surface facing upward, and both the wafer W and the opposing member
602 placed in close proximity to the upper surface of the wafer W
are rotated at their respective specific speeds. Because the
conical plane 627B and the outer side surface 628B and the lower
surface 628A of the projection 628 are rough surfaces having a
hydrophilic property, and the conical plane 627B is connected to
the outer side surface 628B of the projection 628, the etching
liquid supplied to the vicinity of the uppermost portion of the
conical plane 627B flows down on the conical plane 627B and the
side surface 628B, part of which comes around to the lower surface
628A from the side surface 628B and flows down from the lower
surface 628A to the peripheral portion of the upper surface of the
wafer W.
[0264] Because the bottom surface 627A of the cone portion 627 is
formed at a position higher than the lower surface 628A of the
projection 628, the etching liquid having reached the inner
periphery of the lower surface 628A by flowing on the lower surface
628A flows downward vertically from the inner periphery of the
lower surface 628A without going around to the bottom surface 627A
side. The etching liquid supplied to the upper surface of the wafer
W from the opposing member 602 is thus supplied to a peripheral
portion region A outside the intersection line of the cylindrical
surface containing the inner periphery of the lower surface 628A
and the upper surface of the wafer W, and will not be supplied to
the region (device-forming region) inside the intersection
line.
[0265] Meanwhile, when the etching processing is performed to the
wafer W, the etching liquid is supplied from the back-surface
processing nozzle 614 to the center of the lower surface of the
rotating wafer W. The etching liquid supplied to the center of the
lower surface of the wafer W flows toward the periphery by flowing
on the lower surface of the wafer W, part of which comes around to
the end surface of the wafer W. As shown in FIG. 15, the peripheral
portion region A of the upper surface, the back surface, and the
peripheral surface of the wafer W are thereby covered with a flow
of the etching liquid, and an unwanted metal thin film formed on
the peripheral portion region A of the upper surface, the lower
surface, and the peripheral surface of the wafer W is removed by
the etching liquid.
[0266] Also, while the etching liquid is supplied to the wafer W
(while the etching processing is performed), a nitrogen gas is kept
supplied toward the center of the upper surface of the wafer W from
the nitrogen gas supply path 625 in the opposing member 602.
Because a space between the wafer W and the opposing member 602 is
filled with the nitrogen gas thus supplied, entrance of the etching
liquid and an atmosphere containing the etching liquid into this
space from outside can be prevented. It is thus possible to prevent
the metal thin film formed on the device-forming region of the
upper surface of the wafer W from undergoing unwanted etching
processing.
[0267] The rotational speed of the wafer W during the etching
processing is set to a constant speed, for example, within a range
from 150 to 350 rpm, and the rotational speed of the opposing
member 602 is set to be 50 rpm lower than the rotational speed of
the wafer W. By setting the rotational speed of the opposing member
602 lower than the rotational speed of the wafer W, it is possible
to prevent the etching liquid on the opposing member 602 from being
scattered by a centrifugal force while making it easier for the
etching liquid to come around to the peripheral portion region A of
the wafer W. In order to prevent backlash of the etching liquid on
the opposing member 602, a flow rate of the etching liquid to be
supplied from the upper surface nozzle 603 to the upper surface of
the opposing member 602 is set to 0.1 to 0.5 liter per minute.
[0268] When the etching processing continues for a certain time, a
supply of the etching liquid from the upper surface nozzle 603 and
the back-surface processing nozzle 614 is stopped, and instead a
supply of deionized water is started from the upper surface nozzle
603 and the back-surface processing nozzle 614 to the peripheral
portion region A of the upper surface of the wafer W and the lower
surface of the wafer W. The wafer W is kept rotated by the spin
chuck 601 after the supply of deionized water is started. Deionized
water from the upper surface nozzle 603 flows on the upper surface
of the opposing member 602 to be supplied to the peripheral portion
region A of the upper surface of the wafer W, and flows down on the
peripheral surface of the wafer W. Deionized water supplied to the
center of the lower surface of the wafer W from the back-surface
processing nozzle 614 is forced to flow on the lower surface of the
wafer W toward the periphery by a centrifugal force induced by
rotations of the wafer W. Deionized water is thereby supplied
across the region where the etching liquid has been supplied during
the etching processing, that is, across the peripheral portion
region A of the upper surface, the lower surface, and the
peripheral surface of the wafer W, and the rinsing processing that
washes away the etching liquid adhering to the wafer W is thus
achieved. During this rising processing, deionized water supplied
from the upper surface nozzle 603 also washes away the etching
liquid that adhered to the upper surface of the opposing member 602
during the etching processing.
[0269] When the rinsing processing continues for a certain time,
the supply of deionized water from the upper surface nozzle 603 and
the back-surface processing nozzle 614 is stopped. Then, the
rotational speeds of both the wafer W and the opposing member 602
are increased, and drying processing is performed, by which
droplets adhering on the surface of the wafer W are thrown off by a
centrifugal force. During the drying processing, the opposing
member 602 is rotated almost as fast as the wafer W in the same
direction. Also, a nitrogen gas is supplied to a space between the
wafer W and the opposing member 602 from the nitrogen gas supply
path in the opposing member 602. This gives rise to a stable
airflow of a nitrogen gas in the space between the wafer W and the
opposing member 602, and the wafer W can be dried in a satisfactory
manner without leaving any trace of deionized water on the surface
of the wafer W.
[0270] As has been described, according to this embodiment, during
the etching processing of the wafer W, the etching liquid is
supplied to the conical plane (upper surface) 627B of the opposing
member 602 from the upper surface nozzle 603, and the etching
liquid supplied to the conical plane 627B flows on the conical
plane 627B and the side surface 628B, and is supplied to the
peripheral portion region A of the upper surface of the wafer W
from the lower surface of the projection 628 provided on the lower
surface of the opposing member 602. It is thus possible to supply
the etching liquid to the peripheral portion region A of the upper
surface of the wafer W regardless of whether the surface of the
wafer W is hydrophobic or hydrophilic.
[0271] The etching liquid supplied to the upper surface of the
wafer W from the opposing member 602 is supplied only to the
peripheral portion region A outside the intersection line of the
cylindrical surface containing the inner periphery of the lower
surface 628A of the projection 628 and the upper surface of the
wafer W, and will not be supplied to the region inside the
intersection line. It is thus possible to control accurately the
etching width (a width of the peripheral portion region A to which
the etching processing is applied) of the upper surface of the
wafer W depending on the width of the projection 628.
[0272] In the embodiment above, the rotational speed of the
opposing member 602 during the etching processing is set to be 50
rpm lower than the rotational speed of the wafer W. However, in
order to prevent the etching liquid on the opposing member 602 from
being scatted by a centrifugal force, the rotational speed of the
opposing member 602 during the etching process may be set to a
further lower rotational speed (for example, 30 rpm).
Alternatively, in order to ensure the prevention, the opposing
member 602 may be held at rest during the etching processing.
[0273] Also, in the embodiment above, a rough surface (hydrophilic
surface) having a hydrophilic property is provided to the conical
plane 627B of the opposing member 602, etc. by forming the opposing
member 602 from a mold part made of vinyl chloride resin through
cutting treatment. However, the opposing member 602 may be formed
through cast treatment, so that sandblast treatment is applied to
the conical plane 627B and the lower surface 628A and the outside
surface 628B of the projection 628 to make these surfaces as rough
surfaces having a hydrophilic property.
[0274] Also, the lower surface 628A of the projection 628 is made
as a plane placed oppositely almost in parallel with the upper
surface of the wafer W held by the spin chuck 601. However, as
shown in FIG. 16, the lower surface 628A of the projection 628 may
be formed as an inclined plane having a cross section inclined
linearly so as to near the wafer W as it approaches the rotational
axis line of the opposing member 602. Alternatively, as shown in
FIG. 17, the lower surface 628A and the outer side surface 628B of
the projection 628 maybe formed as an inclined plane (rounded
plane) having an almost arc-shaped cross section (convex-curved
cross section). By adopting the arrangement shown in FIG. 16 or
FIG. 17, the etching liquid is allowed to come around to the lower
surface 628A in a satisfactory manner, and a larger quantity of the
etching liquid can be supplied to the peripheral portion region A
of the upper surface of the wafer W.
[0275] Further, as shown in FIG. 18, a groove 291 maybe provided in
the lower end edge portion of the conical plane 627B of the
opposing member 602 together with a communication path 292 that
allows a communication between the groove 291 and a space below the
lower surface 628A of the projection 628, so that the etching
liquid supplied to the conical plane 627B of the opposing member
602 is supplied to the peripheral portion of the upper surface of
the wafer W from the groove 291 through the communication path 292.
The etching liquid supplied to the conical plane 627B of the
opposing member 602 not only passes through the groove 291 and the
communication path 292, but also comes around the side surface 628B
to the lower surface 628A to be supplied to a gap between the lower
surface 628A and the upper surface of the wafer W as with the
embodiment above. It is thus possible to supply a larger quantity
of the etching liquid to the peripheral portion region A of the
upper surface of the wafer W in a more reliable manner.
[0276] Also, in the embodiment above, the ring-shaped projection
628 is formed in the peripheral portion of the bottom surface 627A
of the conical plane 627 along the entire circumference. However,
as shown in FIG. 19, the projection 628 may be formed in the shape
of an arc (a shape that conforms to at least part of the outer
shape of the substrate subject to processing) in part of the
peripheral portion of the bottom surface 627A of the cone portion
627. In this case, the opposing member 602 is not rotated, and
instead the wafer W alone is rotated during the etching processing
of the wafer W. Also, it is preferable that the etching liquid is
supplied from the upper surface nozzle 603 onto the line linking
the center of the projection 628 and the rotational axis line of
the opposing member 602, so that the etching liquid flows toward
the arc-shaped projection 628.
[0277] Further, the processing that removes an unwanted metal film
formed on the wafer W with the use of the etching liquid was
described as an example of the processing applied to the wafer W.
However, the processing applied to the wafer W may be
peripheral-portion rinsing processing that rinses the peripheral
portion of the wafer W with rinsing liquid, or alternatively, it
may be resist removing processing that removes an unwanted resist
film formed on the wafer W with the use of resist removing
liquid.
[0278] The substrate subject to processing is not limited to the
wafer W, and it may be substrates of other kinds, including a glass
substrate for a liquid crystal display, a glass substrate for a
plasma display panel, a glass substrate for a photomask, etc.
[0279] While the above description described embodiments of the
invention in detail, it should be appreciated that these
embodiments represent examples to provide clear understanding of
the technical contents of the invention, and the invention is not
limited to these examples. The sprit and the scope of the
invention, therefore, are limited solely by the scope of the
appended claims.
[0280] This application is based on Application Nos. 2002-240891,
2002-283458, and 2002-346179 filed with the Japanese Patent Office
respectively on Aug. 21, 2002, Sep. 27, 2002, and Nov. 28, 2002,
the entire contents of which are incorporated hereinto by
reference.
* * * * *