U.S. patent application number 10/973350 was filed with the patent office on 2005-07-07 for apparatus and method for processing substrate.
Invention is credited to Ide, Kunihito, Kanda, Hiroyuki, Matsuda, Tetsuo, Mishima, Koji, Nomura, Kazufumi, Suzuki, Hidenao, Toyoda, Hiroshi, Yahiro, Kazuyuki.
Application Number | 20050145482 10/973350 |
Document ID | / |
Family ID | 34648014 |
Filed Date | 2005-07-07 |
United States Patent
Application |
20050145482 |
Kind Code |
A1 |
Suzuki, Hidenao ; et
al. |
July 7, 2005 |
Apparatus and method for processing substrate
Abstract
An apparatus and a method for processing substrate are generally
used for apparatuses for wet-type process of substrate, such as an
electrolytic processing apparatus for use in forming interconnects
by embedding a metal such as copper (Cu) or the like in fine
interconnect patterns (recesses) that are formed in a substrate
such as a semiconductor wafer and for use in forming bumps for
electrical connections. The substrate processing apparatus
includes: a substrate holder for holding a substrate; a first
electrode for contacting the substrate to supply electricity to a
processing surface of the substrate; a second electrode disposed so
as to face the processing surface of the substrate held by the
substrate holder; and a processing liquid supply section for
supplying a processing liquid into the space between the processing
surface of the substrate held by the substrate holder and the
second electrode, wherein the substrate holder is designed to
rotate the substrate during processing in such a manner that
acceleration and slowdown and/or normal rotation and reverse
rotation are repeated.
Inventors: |
Suzuki, Hidenao; (Tokyo,
JP) ; Mishima, Koji; (Tokyo, JP) ; Kanda,
Hiroyuki; (Tokyo, JP) ; Nomura, Kazufumi;
(Tokyo, JP) ; Ide, Kunihito; (Tokyo, JP) ;
Yahiro, Kazuyuki; (Yokohama, JP) ; Toyoda,
Hiroshi; (Yokohama, JP) ; Matsuda, Tetsuo;
(Yokohama, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
34648014 |
Appl. No.: |
10/973350 |
Filed: |
October 27, 2004 |
Current U.S.
Class: |
204/199 ;
204/222; 257/E21.175 |
Current CPC
Class: |
C25D 17/001 20130101;
C25D 17/06 20130101; H01L 21/2885 20130101; C25D 7/123
20130101 |
Class at
Publication: |
204/199 ;
204/222 |
International
Class: |
C25D 017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 30, 2003 |
JP |
2003-371319 |
Claims
What is claimed is:
1. A substrate processing apparatus comprising: a substrate holder
for holding a substrate; a first electrode for contacting the
substrate to supply electricity to a processing surface of the
substrate; a second electrode disposed so as to face the processing
surface of the substrate held by the substrate holder; and a
processing liquid supply section for supplying a processing liquid
into the space between the processing surface of the substrate held
by the substrate holder and the second electrode; wherein the
substrate holder is adapted to rotate the substrate during
processing in such a manner that acceleration and slowdown and/or
normal rotation and reverse rotation are repeated.
2. The substrate processing apparatus according to claim 1, wherein
a high-resistance structure having a higher electric resistance
than the processing liquid is disposed between the substrate held
by the substrate holder and the second electrode.
3. The substrate processing apparatus according to claim 1, wherein
the substrate processing apparatus is an electroplating apparatus
in which the first electrode serves as a cathode and the second
electrode serves as an anode, and the processing liquid is a
plating solution.
4. A substrate processing apparatus comprising: a substrate holder
for holding a substrate; a first electrode for contacting the
substrate to supply electricity to a processing surface of the
substrate; a second electrode disposed so as to face the processing
surface of the substrate held by the substrate holder; a processing
liquid supply section for supplying a processing liquid into the
space between the processing surface of the substrate held by the
substrate holder and the second electrode; and a vibrating
mechanism for vibrating the substrate held by the substrate
holder.
5. The substrate processing apparatus according to claim 4, wherein
the vibrating mechanism is comprised of a vibration exciter for
vibrating the substrate holder.
6. The substrate processing apparatus according to claim 4, wherein
the vibrating mechanism is comprised of an ultrasonic transducer
which transmits ultrasonic waves to the substrate, held by the
substrate holder, through its contact with the back surface of the
substrate.
7. The substrate processing apparatus according to claim 4, wherein
the vibrating mechanism is comprised of an ultrasonic transducer
which transmits ultrasonic waves to the substrate, held by the
substrate holder, in a contactless manner.
8. The substrate processing apparatus according to claim 4, wherein
a high-resistance structure having a higher electric resistance
than the processing liquid is disposed between the substrate held
by the substrate holder and the second electrode.
9. The substrate processing apparatus according to claim 4, wherein
the substrate processing apparatus is an electroplating apparatus
in which the first electrode serves as a cathode and the second
electrode serves as an anode, and the processing liquid is a
plating solution.
10. A substrate processing apparatus comprising: a substrate holder
for holding a substrate; a first electrode for contacting the
substrate to supply electricity to a processing surface of the
substrate; a second electrode disposed so as to face the processing
surface of the substrate held by the substrate holder; a processing
liquid supply section for supplying a processing liquid into the
space between the processing surface of the substrate held by the
substrate holder and the second electrode; and a vibrating
mechanism for vibrating the second electrode.
11. The substrate processing apparatus according to claim 10,
wherein the vibrating mechanism is comprised of a vibration exciter
for vibrating the second electrode in the vertical direction.
12. The substrate processing apparatus according to claim 10,
wherein a high-resistance structure having a higher electric
resistance than the processing liquid is disposed between the
substrate held by the substrate holder and the second
electrode.
13. The substrate processing apparatus according to claim 10,
wherein the substrate processing apparatus is an electroplating
apparatus in which the first electrode serves as a cathode and the
second electrode serves as an anode, and the processing liquid is a
plating solution.
14. A substrate processing apparatus comprising: a substrate holder
for holding a substrate; and a processing liquid supply section for
supplying a processing liquid to a processing surface of the
substrate held by the substrate holder; wherein the substrate
holder is adapted to rotate the substrate during processing in such
a manner that acceleration and slowdown and/or normal rotation and
reverse rotation are repeated.
15. A substrate processing apparatus comprising: a substrate holder
for holding a substrate; a processing liquid supply section for
supplying a processing liquid to a processing surface of the
substrate held by the substrate holder; and a vibrating mechanism
for vibrating the substrate held by the substrate holder.
16. The substrate processing apparatus according to claim 15,
wherein the vibrating mechanism is comprised of a vibration exciter
for vibrating the substrate holder.
17. The substrate processing apparatus according to claim 15,
wherein the vibrating mechanism is comprised of an ultrasonic
transducer which transmits ultrasonic waves to the substrate, held
by the substrate holder, through its contact with the back surface
of the substrate.
18. The substrate processing apparatus according to claim 15,
wherein the vibrating mechanism is comprised of an ultrasonic
transducer which transmits ultrasonic waves to the substrate, held
by the substrate holder, in a contactless manner.
19. A substrate processing method comprising: filling a space
between a processing surface of a substrate, to which electricity
is supplied from a first electrode, and a second electrode disposed
so as to face the processing surface with an electrolytic liquid;
and electrolytically processing the processing surface by applying
a voltage between the first electrode and the second electrode
while rotating the substrate in such a manner that acceleration and
slowdown and/or normal rotation and reverse rotation are
repeated.
20. A substrate processing method comprising: filling a space
between a processing surface of a substrate, to which electricity
is supplied from a first electrode, and a second electrode disposed
so as to face the processing surface with an electrolytic liquid;
and electrolytically processing the processing surface by applying
a voltage between the first electrode and the second electrode
while vibrating at least one of the substrate and the second
electrode.
21. A substrate processing method comprising; supplying a
processing liquid to a processing surface of a substrate; and
processing the processing surface while rotating the substrate in
such a manner that acceleration and slowdown and/or normal rotation
and reverse rotation are repeated.
22. A substrate processing method comprising; supplying a
processing liquid to a processing surface of a substrate; and
processing the processing surface while vibrating the substrate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an apparatus and a method
for processing substrate, and more particularly to an apparatus and
a method for processing substrate which are generally used for
apparatuses for wet-type process of substrate, such as an
electrolytic processing apparatus for use in forming interconnects
by embedding a metal such as copper (Cu) or the like in fine
interconnect patterns (recesses) that are formed in a substrate
such as a semiconductor wafer and for use in forming bumps for
electrical connections.
[0003] 2. Description of the Related Art
[0004] In recent years, instead of using aluminum or aluminum
alloys as a material for forming interconnect circuits on
semiconductor substrates, there is an eminent movement towards
using copper (Cu) which has a low electric resistivity and high
electromigration resistance. Copper interconnects are generally
formed by filling copper into fine recesses formed in a surface of
a substrate. There are known various techniques for forming such
copper interconnects, including CVD, sputtering, and plating.
According to any such technique, a copper film is formed on a
substantially entire surface of a substrate, followed by removal of
unnecessary copper by chemical mechanical polishing (CMP).
[0005] FIGS. 11A through 11C illustrate, in sequence of process
steps, an example of forming such a substrate W having copper
interconnects. As shown in FIG. 11A, an insulating film 2, such as
an oxide film of SiO.sub.2 or a film of low-k material, is
deposited on a conductive layer 1a on a semiconductor base 1 on
which semiconductor devices are formed. Contact holes 3 and
interconnect trenches 4 are formed in the insulating film 2 by the
lithography/etching technique. Thereafter, a barrier layer 5 of TaN
or the like is formed on the surface, and a seed layer 7 as an
electric supply layer for electroplating is formed on the barrier
layer 5.
[0006] Then, as shown in FIG. 11B, copper plating is performed onto
the surface of the substrate W to fill the contact holes 3 and the
interconnect trenches 4 with copper and, at the same time, deposit
a copper film 6 on the insulating film 2. Thereafter, the copper
film 6, the seed layer 5 and the barrier layer 5 on the insulating
film 2 are removed by chemical mechanical polishing (CMP) so as to
make the surface of the copper film 6 filled in the contact holes 3
and the interconnect trenches 4 and the surface of the insulating
film 2 lie substantially on the same plane. Interconnects composed
of the copper film 6, as shown in FIG. 1C, are thus formed.
[0007] With conventional electrolytic processing apparatuses, in
particular, electroplating apparatuses, there is involved the
problem that when carrying out plating of a substrate by bringing a
plating solution into contact with a surface (processing surface)
of the substrate, microbubbles, particles, etc., which may be
present in a small amount in the plating solution, can adhere to
the substrate surface. The presence of microbubbles, particles,
etc., which remain adhering to the substrate surface during the
progress of plating, can cause defects in the device, resulting in
a decreased yield.
[0008] Electroplating is generally carried out while rotating a
substrate in a constant direction. The microbubbles, particles,
etc. adhering to the surface of the substrate, however, cannot be
released easily from the substrate surface only by such rotation of
the substrate, that is, they are likely to remain unremoved on the
substrate surface. Thus, such a rotational operational cannot
sufficiently reduce defects caused by the presence of microbubbles,
particles, etc. on the substrate.
[0009] This situation is almost the same with substrate processing
apparatuses for carrying out other wet processings, such as a
cleaning apparatus for supplying a cleaning liquid onto a surface
of a substrate to clean the surface, and a spin coater for coating
a resist or the like onto a surface of a substrate while rotating
the substrate so as to spread the resist or the like over the
entire surface of the substrate, and the like.
SUMMARY OF THE INVENTION
[0010] The present invention has been made in view of the above
situation in the related art. It is therefore an object of the
present invention to provide an apparatus and a method for
processing a substrate which can prevent the formation of defects
caused by microbubbles, particles, etc. present in a small amount
in a processing liquid such as a plating solution, thereby
increasing the yield.
[0011] In order to achieve the above object, the present invention
provides a substrate processing apparatus comprising: a substrate
holder for holding a substrate; a first electrode for contacting
the substrate to supply electricity to a processing surface of the
substrate; a second electrode disposed so as to face the processing
surface of the substrate held by the substrate holder; and a
processing liquid supply section for supplying a processing liquid
into the space between the processing surface of the substrate held
by the substrate holder and the second electrode; wherein the
substrate holder is adapted to rotate the substrate during
processing in such a manner that acceleration and slowdown and/or
normal rotation and reverse rotation are repeated.
[0012] According to this apparatus, a substrate is rotated during
electrolytic processing, such as plating, in such a manner that
acceleration and slowdown and/or normal rotation and reverse
rotation are repeated so as to stir a processing liquid, such as a
plating solution, around the substrate surface. Accordingly, if
microbubbles, particles, etc. present in a small amount in the
processing liquid adhere to the substrate, they are forced to leave
the substrate. The processing, such as plating, can thus be
progressed in the absence of microbubbles, particles, etc. on the
substrate.
[0013] The present invention provides another substrate processing
apparatus comprising; a substrate holder for holding a substrate; a
first electrode for contacting the substrate to supply electricity
to a processing surface of the substrate; a second electrode
disposed so as to face the processing surface of the substrate held
by the substrate holder; a processing liquid supply section for
supplying a processing liquid into the space between the processing
surface of the substrate held by the substrate holder and the
second electrode; and a vibrating mechanism for vibrating the
substrate held by the substrate holder.
[0014] According to this apparatus, a processing liquid, such as a
plating solution, around a surface of a substrate can be stirred
during electrolytic processing, such as plating, by vibrating the
substrate held by the substrate holder. Thus, this apparatus
likewise can promote the release of microbubbles, particles, etc.
from the substrate.
[0015] The vibrating mechanism is comprised of, for example, a
vibration exciter for vibrating the substrate holder, an ultrasonic
transducer which transmits ultrasonic waves to the substrate, held
by the substrate holder, through its contact with the back surface
of the substrate, or an ultrasonic transducer which transmits
ultrasonic waves to the substrate, held by the substrate holder, in
a contactless manner.
[0016] The present invention provides yet another substrate
processing apparatus comprising: a substrate holder for holding a
substrate; a first electrode for contacting the substrate to supply
electricity to a processing surface of the substrate; a second
electrode disposed so as to face the processing surface of the
substrate held by the substrate holder; a processing liquid supply
section for supplying a processing liquid into the space between
the processing surface of the substrate held by the substrate
holder and the second electrode; and a vibrating mechanism for
vibrating the second electrode.
[0017] According to this apparatus, a processing liquid, such as a
plating solution, around a surface of a substrate can be stirred
during electrolytic processing, such as plating, by vibrating the
second electrode. Thus, this apparatus likewise can promote the
release of microbubbles, particles, etc. from the substrate.
[0018] The vibrating mechanism is comprised of, for example, a
vibration exciter for vibrating the second electrode in the
vertical direction.
[0019] Preferably, a high-resistance structure having a higher
electric resistance than the processing liquid is disposed between
the substrate held by the substrate holder and the second
electrode.
[0020] The substrate processing apparatus is, for example, an
electroplating apparatus in which the first electrode serves as a
cathode and the second electrode serves as an anode, and the
processing liquid is a plating solution.
[0021] The present invention provides yet another substrate
processing apparatus comprising: a substrate holder for holding a
substrate; and a processing liquid supply section for supplying a
processing liquid to a processing surface of the substrate held by
the substrate holder; wherein the substrate holder is adapted to
rotate the substrate during processing in such a manner that
acceleration and slowdown and/or normal rotation and reverse
rotation are repeated.
[0022] The processing of the substrate includes cleaning comprising
supplying a processing liquid, such as a cleaning liquid or pure
water, to the processing surface of the substrate, and spin coating
comprising supplying a processing liquid, such as a resist
solution, to the processing surface of the substrate.
[0023] The present invention provides yet another substrate
processing apparatus comprising: a substrate holder for holding a
substrate; a processing liquid supply section for supplying a
processing liquid to a processing surface of the substrate held by
the substrate holder; and a vibrating mechanism for vibrating the
substrate held by the substrate holder.
[0024] The vibrating mechanism is comprised of, for example, a
vibration exciter for vibrating the substrate holder, an ultrasonic
transducer which transmits ultrasonic waves to the substrate, held
by the substrate holder, through its contact with the back surface
of the substrate, or an ultrasonic transducer which transmits
ultrasonic waves to the substrate, held by the substrate holder, in
a contactless manner.
[0025] The present invention provides a substrate processing method
comprising: filling a space between a processing surface of a
substrate, to which electricity is supplied from a first electrode,
and a second electrode disposed so as to face the processing
surface with an electrolytic liquid; and electrolytically
processing the processing surface by applying a voltage between the
first electrode and the second electrode while rotating the
substrate in such a manner that acceleration and slowdown and/or
normal rotation and reverse rotation are repeated.
[0026] The present invention provides another substrate processing
method comprising: filling a space between a processing surface of
a substrate, to which electricity is supplied from a first
electrode, and a second electrode disposed so as to face the
processing surface with an electrolytic liquid; and
electrolytically processing the processing surface by applying a
voltage between the first electrode and the second electrode while
vibrating at least one of the substrate and the second
electrode.
[0027] The present invention provides yet another substrate
processing method comprising; supplying a processing liquid to a
processing surface of a substrate; and processing the processing
surface while rotating the substrate in such a manner that
acceleration and slowdown and/or normal rotation and reverse
rotation are repeated.
[0028] The present invention provides yet another substrate
processing method comprising; supplying a processing liquid to a
processing surface of a substrate; and processing the processing
surface while vibrating the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a schematic diagram showing an electroplating
apparatus (substrate processing apparatus) according to a first
embodiment of the present invention;
[0030] FIG. 2 is a schematic diagram showing an electroplating
apparatus (substrate processing apparatus) according to a second
embodiment of the present invention;
[0031] FIG. 3 is a schematic diagram showing an electroplating
apparatus (substrate processing apparatus) according to a third
embodiment of the present invention;
[0032] FIG. 4 is a schematic diagram showing an electroplating
apparatus (substrate processing apparatus) according to a fourth
embodiment of the present invention;
[0033] FIG. 5 is a schematic diagram showing an electroplating
apparatus (substrate processing apparatus) according to a fifth
embodiment of the present invention;
[0034] FIG. 6 is a cross-sectional diagram showing the main portion
of an electroplating apparatus (substrate processing apparatus)
according to a sixth embodiment of the present invention;
[0035] FIG. 7 is a diagram showing the positional relationship
between a substrate, a lip seal and a plating solution supply
section in the electroplating apparatus shown in FIG. 6 upon
plating;
[0036] FIG. 8 is a cross-sectional diagram showing the main portion
of an electroplating apparatus (substrate processing apparatus)
according to a seventh embodiment of the present invention;
[0037] FIG. 9 is a diagram showing the positional relationship
between a substrate, a lip seal and a plating solution supply
section in the electroplating apparatus shown in FIG. 8 upon
plating;
[0038] FIG. 10 is a graph showing the results of measurement of the
number of defects formed in the plated film of a substrate in cases
where plating is carried out while rotating the substrate at a
constant speed in one direction (reference), where plating is
carried out while vibrating the substrate with a vibration exciter
(vibration exciter), and where plating is carried out while
repeating acceleration and slowdown of the rotational speed of the
substrate (acceleration and slowdown); and
[0039] FIGS. 11A through 11C are diagrams illustrating, in a
sequence of process steps, an example of forming copper
interconnects by plating.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0040] Preferred embodiments of the present invention will now be
described with reference to the drawings. The following description
illustrates application of the present invention to electroplating
apparatuses using a plating solution as a processing liquid, and
utilizing the first electrode as a cathode and the second electrode
as an anode. It is, of course, possible to apply the present
invention to electrolytic etching apparatuses by using an
electrolytic etching liquid as a processing liquid, and utilizing
the first electrode as an anode and the second electrode as a
cathode.
[0041] FIG. 1 shows an electroplating apparatus (substrate
processing apparatus) according to a first embodiment of the
present invention. As shown in FIG. 1, the electroplating apparatus
includes a substrate holder 14, coupled to an upper end of a main
shaft 12, which is rotatable and vertically movable by a drive
section 10, for detachably holding a substrate W with its front
surface facing upwardly (face up), and a vertically movable
electrode head 16 disposed above the substrate holder 14.
[0042] A ring-shaped lip seal 18 formed of an elastic material and
a leaf spring-like cathode (first electrode) 20 surrounding the lip
seal 18 are concentrically disposed above the substrate holder 14
such that they cover the peripheral region of the substrate holder
14. When the substrate holder 14 holding a substrate W is raised,
the lip seal 18 comes into contact with a peripheral portion of the
substrate W. By further raising the substrate holder 14, the lip
seal 18 is brought into pressure contact with the peripheral
portion of the substrate W, thereby watertightly sealing the
peripheral portion. A plating cell 22 is thus formed by the upper
surface of the substrate W and the lip seal 18. At the same time,
the cathode 20 is pressed against a peripheral portion of the
substrate W to supply electricity thereto, so that a seed layer 7
(see FIG. 11) formed in the surface of the substrate W is connected
to the cathode of a power source 24 and becomes a cathode.
[0043] Since the cathode 20 is disposed outside the lip seal 18,
the cathode 20 can be prevented from being contaminated with a
plating solution 26 introduced into the plating cell 22.
[0044] The substrate holder 14 includes a disc-shaped substrate
stage 28 for placing and holding the substrate W on the upper
surface, and a plurality of openable and closable clamps 30 for
clamping a peripheral portion of the substrate W placed on the
substrate stage 28.
[0045] The electrode head 16 is supported at the free end of a
pivot arm 34 that is fixed to the upper end of a vertically movable
lifting shaft 32. The electrode head 16 includes a downwardly-open
cylindrical housing 36 and a high-resistance structure 38 disposed
such that it closes the bottom opening of the housing 36. The
housing 36 has, at a lower portion thereof, a recessed portion 36a
extending in the circumferential direction, while the
high-resistance structure 38 has at its top a flange portion 38a.
The high-resistance structure 38 is held in the housing 36 by
insertion of the flange portion 38a into the recessed portion 36a.
A plating solution chamber 40 is thus formed over the
high-resistance structure 38 in the housing 36.
[0046] The high-resistance structure 38 is composed of, for
example, a porous ceramic, such as alumina, SiC, mullite, zirconia,
titania or cordierite, or a hard porous body, such as a sintered
body of polypropylene or polyethylene, or a compound thereof, or a
woven or non-woven fabric. For example, a porous ceramic plate may
be used having a pore diameter of 30 to 200 .mu.m in the case of an
alumina ceramic, or not more than 30 .mu.m in the case of SiC, a
porosity of 20 to 95%, and a thickness of 1 to 20 mm, preferably 5
to 20 mm, more preferably 8 to 15 mm. According to this embodiment,
the high-resistance structure 38 is composed of a porous alumina
ceramic plate, for example, having a porosity of 30% and an average
pore diameter of 100 .mu.m. Though the high-resistance structure
38, composed of such a porous ceramic plate, itself is an
insulating material, it has an electric conductivity when it
contains a plating solution. In particular, a plating solution can
penetrate deep into the porous ceramic plate in the thickness
direction though complicated, fairly long paths of the pores. This
can provide the high-resistance structure 38 containing the plating
solution with an electric conductivity which is lower than the
electric conductivity of the plating solution.
[0047] The provision of the high-resistance structure 38, which can
thus have a high electric resistance in the housing 36, can make
the influence of the resistance of the seed layer 7 and copper film
6 (see FIG. 11B) as small as negligible. Thus, a variation of
current density in the entire surface of the substrate W due to the
electric resistance can be made small, thereby improving the
uniformity of a plated film over the entire surface of the
substrate.
[0048] An anode (second electrode) 42 to be connected to the anode
of the power source 24 is disposed over the high-resistance
structure 38 in the housing 36. A plating solution supply pipe 44
as a plating solution supply section is mounted to the upper
surface of the anode 42. The plating solution supply pipe 44 has a
manifold structure so that a plating solution can be supplied
uniformly to the high-resistance structure 38. Thus, a number of
narrow tubes 46, which are in fluid communication with the plating
solution supply pipe 44, are coupled to the pipe 44 at
predetermined positions along the long direction of the pipe 44.
The high-resistance structure 38 and the anode 42 have narrow holes
at positions corresponding to the narrow tubes 46, and the narrow
tubes 46 extend downwardly in the narrow holes. Further, the anode
42 has a large number of through-holes 42a vertically penetrating
the anode 42.
[0049] Though not shown diagrammatically, the housing 36 is
provided with a plating solution suction pipe for sucking in the
plating solution in the plating solution chamber 40 within the
housing 36.
[0050] The plating solution, introduced into the plating solution
supply pipe 44, passes through the narrow tubes 46 and is supplied
into the plating cell 22 defined by the substrate W, held by the
substrate holder 14, and the lip seal 18. On the other hand, the
plating solution 26 has been held within the high-resistance
structure 38, and the plating solution has been stored at a certain
surface level in the plating solution chamber 40. The space between
the anode 42 and the substrate W held by the substrate holder 14 is
thus filled with the plating solution 26.
[0051] In order to suppress generation of slime, the anode 42 is
made of copper containing 0.03 to 0.05% of phosphorus
(phosphorus-containing copper). However, an insoluble electrode may
also be employed.
[0052] According to this embodiment, a band-shaped insulating
member 48 is wrapped around the circumferential surface of the
high-resistance structure 38 to prevent an electric current from
flowing out of the circumferential surface of the high-resistance
structure 38. An elastic material, such as a fluorine-contained
rubber, may be used for the insulating member 48.
[0053] The operation of the electroplating apparatus of this
embodiment in carrying out plating will now be described. The
following description illustrates the case of providing a substrate
W, as shown in FIG. 11A, having a seed layer 7, serving as an
electric supply layer in electroplating, formed in the front
surface (processing surface), and carrying out copper
electroplating of the surface of the substrate W to embed copper
into contact holes 3 and interconnect trenches 4 as fine
interconnect recesses.
[0054] First, the substrate W having the seed layer 7 is held with
the front surface (processing surface) facing upwardly by the
substrate holder 14, and the substrate holder 14 is raised to bring
a peripheral portion of the substrate W into pressure contact with
the lip seal 18, thereby forming the plating cell 22 defined by the
upper surface of the substrate W and the lip seal 18. At the same
time, the cathode 20 is brought into contact with the seed layer 7.
The electrode head 16, on the other hand, is in an idling position.
The plating solution is supplied into the plating solution chamber
40 in the housing 36, and the plating solution is held within the
high-resistance structure 38.
[0055] Next, the electrode head 16 is moved from the idling
position to a position right above the substrate holder 14 and is
then lowered. The lowering is stopped when the lower surface of the
high-resistance structure 38 has reached a position close to the
front surface of the substrate W held by the substrate holder 14,
the position being at a distance of about 0.5 mm to 3 mm from the
surface of the substrate W. Thereafter, the plating solution 26 is
supplied through the plating solution supply pipe 44 into the
plating cell 22 defined by the substrate W and the lip seal 18,
thereby filling the space between the surface of the substrate W
and the cathode 20 with the plating solution 26. A plating voltage
is applied from the power source 24 to between the anode 42 and the
seed layer 7 as a cathode to carry out plating of the surface of
the seed layer 7.
[0056] During the plating, the substrate W held by the substrate
holder 14 is rotated in such a manner that acceleration and
slowdown and/or normal rotation and reverse rotation are repeated.
For example, a step of rotating the substrate W at an acceleration
A for a time a until the rotational speed reaches X, and a step of
rotating the substrate W at an acceleration B for a time .beta.
until the rotational speed reaches Y are repeated, as shown in
Table 1 below. The accelerations A, B may either be positive
accelerations, negative accelerations or a combination of a
positive acceleration and a negative acceleration. The both
rotations of the substrate W for the rotational speeds X, Y may be
normal rotations or reverse rotations.
1TABLE 1 Step 1 2 3 4 5 6 Repeated Rotational speed X Y X Y X Y
.fwdarw. (min.sup.-1) Acceleration A B A B A B Time (sec) .alpha.
.beta. .alpha. .beta. .alpha. .beta. .fwdarw.
[0057] According to this embodiment, the substrate W is thus
rotated during electrolytic processing, such as plating, in such a
manner that acceleration and showdown and/or normal rotation and
reverse rotation are repeated so as to stir the plating solution 26
around the surface of the substrate W. Accordingly, if
microbubbles, particles, etc. present in a small amount in the
plating solution 26 adhere to the substrate W, they are forced to
leave the substrate W. Plating can thus be progressed in the
absence of microbubbles, particles, etc. on the substrate W.
[0058] When the copper film 6 (see FIG. 11B) formed on the surface
of the seed layer 7 has reached a predetermined thickness, the
application of plating voltage is stopped to terminate plating. The
electrode head 16 is then raised, and the plating solution 26
remaining on the surface of the substrate W is removed by suction.
Thereafter, the substrate holder 14 is lowered, and the substrate W
after plating, held by the substrate holder 14, is transferred to
the next process step.
[0059] FIG. 2 shows an electroplating apparatus (substrate
processing apparatus) according to a second embodiment of the
present invention. This embodiment differs from the embodiment
shown in FIG. 1 in that the rotatable and vertically movable main
shaft 12 is divided into upper and lower shafts, and a vibration
exciter 50 for vibrating the upper main shaft 12a vertically and/or
horizontally is mounted between the two shafts. The vibration
exciter 50 is actuated during plating to vibrate a substrate W,
held by the substrate holder 14, vertically and/or
horizontally.
[0060] The plating solution 26 around the surface of the substrate
W can be stirred also by thus vibrating the substrate W, held by
the substrate holder 14, vertically and/or horizontally by the
vibration exciter 50, enabling the progress of plating in the
absence of microbubbles, particles, etc. on the substrate W, as
described above.
[0061] FIG. 3 shows an electroplating apparatus (substrate
processing apparatus) according to a third embodiment of the
present invention. This embodiment differs from the embodiment
shown in FIG. 1 in that an ultrasonic transducer 52, which
transmits ultrasonic waves to a substrate W, held by the substrate
holder 14, through its contact with the back surface of the
substrate W, is mounted to the substrate holder 14. The ultrasonic
transducer 52 is actuated during plating to vibrate the substrate W
held by the substrate holder 14.
[0062] The plating solution 26 around the surface of the substrate
W can be stirred also by thus vibrating the substrate W, held by
the substrate holder 14, by the ultrasonic transducer 52, enabling
the progress of plating in the absence of microbubbles, particles,
etc. on the substrate W, as described above.
[0063] FIG. 4 shows an electroplating apparatus (substrate
processing apparatus) according to a fourth embodiment of the
present invention. This embodiment differs from the embodiment
shown in FIG. 3 in that an ultrasonic transducer 56, for example, a
speaker, which transmits ultrasonic waves to a substrate W, held by
the substrate holder 14, in a contactless manner, is mounted to an
apparatus frame 54 housing the plating apparatus. The ultrasonic
transducer 56 is actuated during plating to vibrate the substrate
W, held by the substrate holder 14, in a contactless manner.
[0064] FIG. 5 shows an electroplating apparatus (substrate
processing apparatus) according to a fifth embodiment of the
present invention. This embodiment differs from the embodiment
shown in FIG. 1 in that a vibration exciter 58 for vibrating the
electrode head 16 vertically and/or horizontally is interposed
between the pivot arm 34 and the electrode head 16. The vibration
exciter 58 is actuated during plating to vibrate the anode 42
vertically and/or horizontally.
[0065] The vibration of the anode 42 is transmitted to the plating
solution 26 directly or indirectly. The plating solution 26 around
the surface of the substrate W can therefore be stirred also by
thus vibrating the anode 42 vertically and/or horizontally by the
vibration exciter 58, enabling the progress of plating in the
absence of microbubbles, particles, etc. on the substrate W, as
described above.
[0066] FIGS. 6 and 7 show an electroplating apparatus (substrate
processing apparatus) according to a sixth embodiment of the
present invention. This embodiment differs from the embodiment
shown in FIG. 1 in that instead of the plating solution supply pipe
44 of FIG. 1, a plating solution supply section 104, positioned
beside the anode 42 and the high-resistance structure 38, and
vertically penetrating the peripheral wall of the housing 36, is
provided within the peripheral wall of the housing 36. According to
this embodiment, the plating solution supply section 104 is
comprised of a tube with a nozzle-shaped lower end. In FIG. 6 is
shown a plating solution discharge outlet 103, connected to the
housing 36, for sucking in and discharging the plating solution 26
in the plating solution chamber 40.
[0067] The plating solution supply section 104 is to supply the
plating solution 26 from the side of the anode 42 and the
high-resistance structure 38 into the space between the substrate W
and the high-resistance structure 38, and the lower-end nozzle
portion opens to the space between the lip seal 18 and the
high-resistance structure 38.
[0068] The plating solution 26, supplied from the plating solution
supply section 104 at the time of supply of the plating solution,
flows in one direction over the front surface of the substrate W,
as shown in FIG. 7, and by the flow of plating solution, air in the
space between the substrate W and the high-resistance structure 38
is forced out of the space. The space is thus filled with the
fresh, composition-adjusted plating solution injected from the
plating solution supply section 104, and the plating solution is
stored in the plating cell 22 defined by the substrate W and the
lip seal 18.
[0069] By thus injecting the plating solution from the side of the
anode 42 and the high-resistance structure 38 into the space
between the substrate W and the high-resistance structure 38, the
filling of plating solution can be carried out without provision
of, for example, a plating solution supply tube composed of an
insulating material, which may disturb the electric field
distribution, within the high-resistance structure 38. This can
make the electric field distribution uniform over the entire
surface of the substrate even it the substrate has a large area.
Furthermore, the plating solution, which has been held in the
high-resistance structure 38, can be prevented from leaking out of
the high-resistance structure 38 upon the injection of a fresh
plating solution. Accordingly, the fresh, composition-adjusted
plating solution can be supplied into the space between the
substrate W held by the substrate holder 14 (see e.g. FIG. 1) and
the high-resistance structure 38.
[0070] FIGS. 8 and 9 show an electroplating apparatus (substrate
processing apparatus) according to a seventh embodiment of the
present invention. This embodiment differs from the embodiment
shown in FIGS. 6 and 7 in that a plating solution suction section
130 for sucking in the plating solution injected between the
substrate W and the high-resistance structure 38 is provided beside
the anode 42 and the high-resistance structure 38, and on the
opposite side of the high-resistance structure 38 from the plating
solution supply section 104 in the housing 36. Though not shown
diagrammatically, the plating solution 26, supplied into the space
between the substrate W and the high-resistance structure 38 and
stored in the plating cell 22 defined by the substrate W and the
lip seal 18, is returned from the plating solution suction section
130 to a plating solution tank (not shown) in a circulatory
manner.
[0071] According to this embodiment, the electrode head 16 is
lowered until the distance between the substrate W and the
high-resistance structure 38 becomes, for example, about 0.5 to 3
mm, and the plating solution is injected from the plating solution
supply section 104 into the space between the substrate W and the
high-resistance structure 38. The plating solution 26 injected
fills the space and is stored in the plating cell 22 defined by the
substrate W and the lip seal 18 while the plating solution 26 is
sucked in by the plating solution suction section 130. Plating of
the surface of the substrate W is thus carried out while keeping
the space between the substrate W and the high-resistance structure
38 filled with the plating solution flowing in one direction, as
shown in FIG. 9.
[0072] According to this embodiment, the plating solution 26 is
thus injected from the side of the high-resistance structure 38
into the space between the substrate w and the high-resistance
structure 38, and the plating solution 26 is allowed to circulate
so that the plating solution 26 constantly flows between the
substrate W and the high-resistance structure 38. This can prevent
the formation of plating defects, i.e. non-plated portions, caused
by a stop of the flow of plating solution during electroplating.
Further, rotating the substrate according to necessity enables the
plating solution to flow at an even speed over the central and
peripheral portions of the substrate W.
[0073] FIG. 10 shows the results of measurement of the number of
defects formed in the plated film of a substrate (No. 3) (vibration
exciter), the plated film being obtained by plating of the surface
of the substrate carried out by keeping the substrate, held by a
substrate holder, and a high-resistance structure close to each
other and vibrating the substrate with a vibration exciter during
plating. FIG. 10 also shows the results of measurement of the
number of defects formed in the plated films of two substrates (No.
4, No. 5) (acceleration and slowdown), the plated films each being
obtained by plating of the surface of the substrate carried out by
keeping the substrate, held by the substrate holder, and the
high-resistance structure close to each other and repeating
acceleration and slowdown of the rotational speed of the substrate
during plating. For comparison, FIG. 10 also shows the results of
measurement of the number of defects formed in the plated films of
two substrates (No. 1, No. 2) (reference), the plated films each
being obtained by plating of the surface of the substrate carried
out by keeping the substrate, held by the substrate holder, and the
high-resistance structure close to each other and rotating the
substrate at a constant speed in one direction.
[0074] The data in FIG. 10 demonstrates the fact that the number of
defects formed in the plated film of a substrate can be decreased
by carrying out plating of the substrate while vibrating the
substrate by a vibration exciter, or while repeating acceleration
and slowdown of the rotational speed of the substrate.
[0075] Though the above-described embodiments relate to application
of the present invention to electroplating apparatuses using a
plating solution as a processing liquid, and utilizing the first
electrode as a cathode and the second electrode as an anode, the
present invention, of course, is applicable to electrolytic etching
apparatuses by using an electrolytic etching liquid as a processing
liquid, and utilizing the first electrode as an anode and the
second electrode as a cathode.
[0076] Further, though the above embodiments relate to electrolytic
processing apparatuses provided with the first electrode and the
second electrode, the present invention is also applicable to
substrate processing apparatuses for performing wet processing,
such as an electroless plating apparatus, a cleaning apparatus and
a spin coater, by omitting the first electrode and the second
electrode or by not applying a voltage between the first electrode
and the second electrode.
[0077] According to the present invention, a processing liquid,
such as a plating solution, around a substrate surface is stirred
during electrolytic processing, such as plating, thereby promoting
release of microbubbles, particles, etc. adhering to the substrate
surface. This can prevent the microbubbles, particles, etc. from
remaining on the substrate surface during the progress of plating,
thereby increasing the yield. This holds for other wet processings
than plating, such as cleaning and spin coating.
* * * * *