U.S. patent application number 09/253037 was filed with the patent office on 2001-08-02 for scrubbing apparatus.
Invention is credited to HIROSE, KEIZO, KONISHI, NOBUO, SEKIGUCHI, KENJI.
Application Number | 20010010103 09/253037 |
Document ID | / |
Family ID | 13014847 |
Filed Date | 2001-08-02 |
United States Patent
Application |
20010010103 |
Kind Code |
A1 |
KONISHI, NOBUO ; et
al. |
August 2, 2001 |
SCRUBBING APPARATUS
Abstract
A scrubbing apparatus is provided which sufficiently cleans
every site on the wafer by a cleaning accelerating action of
ultrasonic waves, the scrubbing apparatus comprising a substrate
support section for supporting a substrate horizontally and
substantially in contact with a circumferential portion of the
substrate while front side and back side surfaces of the substrate
are substantially kept untouched in operation by the substrate,
rotation drive means for driving the substrate support section to
rotate in order to give a rotation force to the substrate, a brush
for scrub-cleaning the substrate while contacting at least the
front surface, a main nozzle provided with a first supply circuit
for supplying a cleaning liquid in at least a central region of the
substrate, an auxiliary nozzle provided with a second supply
circuit for supplying the cleaning liquid in at least a peripheral
region of the substrate, and an ultrasonic oscillator for applying
ultrasonic waves to the cleaning liquid supplied on the substrate
from an auxiliary nozzle.
Inventors: |
KONISHI, NOBUO;
(YAMANASHI-KEN, JP) ; SEKIGUCHI, KENJI; (KOFU-SHI,
JP) ; HIROSE, KEIZO; (KOFU-SHI, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Family ID: |
13014847 |
Appl. No.: |
09/253037 |
Filed: |
February 19, 1999 |
Current U.S.
Class: |
15/77 ; 118/52;
134/153; 134/902; 15/102; 15/88.2; 15/88.3; 15/97.1 |
Current CPC
Class: |
H01L 21/67051 20130101;
Y10S 134/902 20130101; H01L 21/67046 20130101; B08B 1/04 20130101;
B08B 3/12 20130101 |
Class at
Publication: |
15/77 ; 15/88.2;
15/88.3; 15/97.1; 15/102; 118/52; 134/153; 134/902 |
International
Class: |
B08B 003/00; B05C
013/00; B05C 013/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 20, 1998 |
JP |
10-056001 |
Claims
1. A scrubbing apparatus comprising: a substrate support section
for supporting a substrate horizontally and substantially in
contact with a circumferential portion of the substrate while front
side and back side surfaces of the substrate are substantially kept
untouched in operation by the substrate; rotation drive means for
driving the substrate support section to rotate in order to give a
rotation force to the substrate; a brush member for scrub-cleaning
the substrate while contacting at least said front side surface; a
main nozzle provided with a first supply circuit for supplying a
cleaning liquid in at least a central region of the substrate; an
auxiliary nozzle provided with a second supply circuit for
supplying the cleaning liquid in at least a peripheral region of
the substrate; and an ultrasonic oscillator for applying ultrasonic
waves to the cleaning liquid supplied on the substrate from an
auxiliary nozzle.
2. A scrubbing apparatus according to claim 1, wherein the
substrate support section has a plurality of rotary guides each
having the shape of a frustum of right circular cone which are put
in contact with the circumferential portion of the substrate and
the rotation drive means drives at least one of the plurality of
rotary guides to rotate.
3. A scrubbing apparatus according to claim 1, wherein the
substrate support section has one pair of support rings for
supporting the substrate in such a manner that the circumferential
portion of the substrate is pressed from the upper and lower sides,
and the rotation drive mechanism drives at least one of the support
rings to rotate.
4. A scrubbing apparatus according to claim 1, wherein the
ultrasonic oscillator is mounted to the auxiliary nozzle so that
ultrasonic waves are applied to the cleaning liquid which passes
through the second supply circuit.
5. A scrubbing apparatus according to claim 1, wherein the
ultrasonic oscillator includes a transducer having a helical
form.
6. A scrubbing apparatus according to claim 1, further comprising:
control means for controlling the ultrasonic oscillator, wherein
the control means controls the ultrasonic oscillator so that the
cleaning liquid supplied on the substrate from the main nozzle is
also applied with ultrasonic waves and that a power of ultrasonic
waves applied in the peripheral portion of the substrate is
stronger than in the central region of the substrate and the
cleaning liquid applied with ultrasonic waves is supplied not only
in the peripheral region of the substrate from the auxiliary
nozzle, but in the central region of the substrate from the main
nozzle.
7. A scrubbing apparatus according to claim 1, wherein a patterned
thin film is formed on the surface of the substrate.
8. A scrubbing apparatus according to claim 1, wherein the surface
of the substrate is processed by chemical mechanical polishing.
9. A scrubbing apparatus comprising: a substrate support section
for supporting a substrate horizontally and substantially in
contact with a circumferential portion of the substrate while front
side and back side surfaces of the substrate are substantially kept
untouched in operation by the substrate; rotation drive means for
driving the substrate support section to rotate in order to give a
rotation force to the substrate; a brush member for scrub-cleaning
the substrate while contacting at least said front side surface; a
nozzle for supplying a cleaning liquid on the substrate; a nozzle
movement mechanism for moving the nozzle; an ultrasonic oscillator
for applying ultrasonic waves to the cleaning liquid supplied on
the substrate from the nozzle; and control means for controlling
the ultrasonic oscillator and the nozzle movement mechanism so that
ultrasonic waves are applied to the cleaning liquid supplied to at
least the peripheral region of the substrate.
10. A scrubbing apparatus according to claim 9, wherein the control
means controls the ultrasonic oscillator so that a power of
ultrasonic waves applied in the peripheral region of the substrate
is stronger than in the central region of the substrate and
controls the nozzle movement mechanism to move the nozzle so that
the cleaning liquid applied with ultrasonic waves is supplied in
the peripheral region and central region of the substrate from the
nozzle.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a scrubbing apparatus for
cleaning the surface of a substrate which has been subjected to
film formation or polishing processing.
[0003] 2. Description of the Prior Art
[0004] Significant defects occur in a patterned circuit of a
semiconductor device when contamination such as particles, organic
material and metallic ions are attached on the surface of a
semiconductor wafer in a photolithographic process. Hence, it is
very important to keep a wafer surface in a clean condition. For
this reason, the wafer surface is cleaned in a photolithographic
process any time when a necessity arises. For example, after a film
formation process such as interlayer insulating film formation and
a polishing process such as chemical mechanical polishing
(hereinafter referred to as "CMP"), a wafer is rubbed by a brush
while pouring a cleaning liquid on the wafer surface and
contamination is thereby removed from the wafer surface. In such
brush cleaning, a scrubbing apparatus with a spin chuck and a
rotary brush is employed. The spin chuck is provided with a
plurality of movable support members for supporting a wafer. When
the spin chuck is rotated, an upper portion of the movable support
members are inward inclined by a centrifugal force and put into
contact with a circumferential portion of the wafer, so that the
wafer is fast held so as not to get away from the spin chuck. In
such a conventional brushing apparatus, however, since the brush
collides against the movable support members, cleaning actions are
required to progress so as to avoid such an interference. When
cleaning is performed in such a brushing apparatus while avoiding
the collision, a cleaning effect along the wafer circumferential
portion comes to be short.
[0005] Recently, CMP has well been used as a processing technique
for planarization of a pattern forming surface and when a pattern
forming surface of a wafer is polished by CMP, much of foreign
matter attaches along a peripheral portion of the wafer surface and
on an edge surface of the wafer: such as particles resulted from a
work itself, a polishing slurry and the like. For this reason,
demand from users for cleaning the wafer peripheral portion to a
sufficient extent has progressively been increased.
BRIEF SUMMARY OF THE INVENTION
[0006] It is accordingly an object of the present invention is to
provide a scrubbing apparatus for sufficiently cleaning a
peripheral portion of a substrate.
[0007] A scrubbing apparatus according to the present invention
comprises: a substrate support section for supporting a substrate
horizontally and substantially in contact with a circumferential
portion of the substrate while front side and back side surfaces of
the substrate are substantially kept untouched in operation by the
substrate; rotation drive means for driving the substrate support
section to rotate in order to give a rotation force to the
substrate; a brush member for scrub-cleaning the substrate while
contacting at least the front side surface; a main nozzle provided
with a first supply circuit for supplying a cleaning liquid in at
least a central region of the substrate; an auxiliary nozzle
provided with a second supply circuit for supplying the cleaning
liquid in at least a peripheral region of the substrate; and an
ultrasonic oscillator for applying ultrasonic waves to the cleaning
liquid supplied on the substrate from an auxiliary nozzle.
[0008] A scrubbing apparatus according to the present invention
comprises: control means for controlling the ultrasonic oscillator,
wherein the control means controls the ultrasonic oscillator so
that the cleaning liquid supplied on the substrate from the main
nozzle is also applied with ultrasonic waves and that a power of
ultrasonic waves applied in the peripheral portion of the substrate
is stronger than in the central region of the substrate and the
cleaning liquid applied with ultrasonic waves is supplied not only
in the peripheral region of the substrate from the auxiliary
nozzle, but in the central region of the substrate from the main
nozzle.
[0009] Since the cleaning liquid which is applied with ultrasonic
waves penetrates into even a small gap with ease, every points on a
substrate can be cleaned thoroughly. Therefore, the cleaning liquid
can reach even a site which a brush member cannot contact, such as
a clearance between a substrate support section and a substrate,
and sufficient cleaning can be realized, perfectly covering the
entire surface of the substrate by a cleaning acceleration action
of ultrasonic waves.
[0010] Besides, since the substrate support section and the
substrate are rotated in a relative manner, a contact site between
both is constantly changed and therefore such a movement eliminates
a site on the substrate where no cleaning occurs.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0011] FIG. 1 is a partial cutaway, perspective view schematically
showing a scrubbing system for cleaning a semiconductor wafer;
[0012] FIG. 2 is a schematic plan view showing a scrubbing
apparatus according to an embodiment of the present invention;
[0013] FIG. 3 is a perspective view showing a main portion of the
scrubbing apparatus according to the embodiment of the present
invention;
[0014] FIG. 4 is a view showing the main portion of the scrubbing
apparatus when viewed from a side;
[0015] FIG. 5 is a view showing a brush drive mechanism when viewed
from a side;
[0016] FIG. 6 is a sectional view of an ultrasonic cleaning nozzle
(a megasonic nozzle) and a block diagram showing a cleaning liquid
supply circuit;
[0017] FIG. 7 is a schematic view for illustrating actions in wafer
cleaning;
[0018] FIG. 8 is a perspective view schematically showing a
scrubbing apparatus according to a second embodiment of the present
invention;
[0019] FIG. 9 is a view showing the scrubbing apparatus according
to the second embodiment of the present invention when viewed from
a side;
[0020] FIG. 10 is an enlarged view showing a wafer supporting part
of a pressed-between type;
[0021] FIG. 11 is a enlarged view showing a rotary supporting
section for supporting a wafer rotatably;
[0022] FIG. 12 is a view showing a scrubbing apparatus according to
a third embodiment of the present invention; and
[0023] FIG. 13 is a plan view showing an arm holder and a spin
chuck when a wafer is transferred.
DETAILED DESCRIPTION OF THE INVENTION
[0024] Below, various preferred embodiments of the present
invention will be detailed with reference to the accompanying
drawings.
[0025] A cleaning system 1 comprises a load/unload section 2 in
which semiconductor wafers W are transported in and out together
with a cassette C while a lot of 25 wafers as unit are accommodated
in the cassette C. In the load/unload section 2, a table is
provided and, for example, three cassettes are placed on the table.
A first transport section 5 is formed along the table and a first
transport arm mechanism 3 is provided in the first transport
section 5. The first transport arm mechanism 3 comprises: a
plurality of holders 3a, 3b; a forward/backward drive mechanism for
moving the holders 3a, 3b forward or backward; an X axis movement
mechanism for moving the holders 3a, 3b in an X axis direction; a Z
axis movement mechanism for moving the holders 3a, 3b in a Z axis
direction; and a .theta. rotation mechanism for rotating holders
3a, 3b about Z axis.
[0026] A transport-in/buffer mechanism (not shown) is provided on
one side of the first transport section 5 and a
transport-out/buffer mechanism (not shown) is provided on the other
side of the first transport section 5. The first transport arm
mechanism 3 takes out wafers W before cleaning from a cassette C
one by one with a holder 3a in a lower place and places the wafers
W on a transport-in/buffer mechanism, while the first transport
mechanism 3 takes out wafers W after cleaning from a
transport-out/buffer mechanism with a holder 3b in an upper place
and transports the wafers W into a cassette C one by one.
[0027] A second transport section 10 is formed along the first
transport section 5 in a adjacent manner and a second transport arm
mechanism 8 is provided in the second transport section 10 in a
movable manner. The second transport arm mechanism 8 comprises: a
plurality of holders 8a, 8b, 8c; a forward/backward drive mechanism
for moving the holders 8a, 8b, 8c forward or backward; an X axis
movement mechanism for moving the holders 8a, 8b, 8c in an X axis
direction; a Z axis movement mechanism for moving the holders 8a,
8b, 8c in a Z axis direction; and a .theta. rotation mechanism for
rotating the holders 8a, 8b, 8c about Z axis. The second transport
arm mechanism 8 takes out wafers W before cleaning from a cassette
C one by one with a holder 8a in a lower place and places the
wafers W on a transport-in/buffer mechanism 11, while the second
transport arm mechanism 8 takes out wafers W after cleaning from a
transport-out/buffer mechanism 12 with a holder 8b in an upper
place and transports the wafers W into a cassette C one by one.
[0028] A process section 6 is provided next to the second transport
section 10. The process section 6 comprises: cleaning units 13, 14,
16, 17 for cleaning wafers W; and a drying unit for drying wafers W
(not shown). The cleaning units 13, 16 are used for cleaning of the
same kind and arranged in two levels, one on the other. The
cleaning units 14, 17 are used for cleaning of the same kind and
arranged in two levels, one on the other. A treatment liquid supply
section 19 is provided on the back side of the cleaning units 13,
14, 16, 17. The treatment liquid supply section 19 comprises: a
plurality of treatment liquid supply sources 101, 102 and one kind
of a treatment liquid selected from the plurality of treatment
liquid supply sources 101, 102 is supplied to nozzles 41, 51 as
shown in FIGS. 2, 3, 4 and 6.
[0029] Wafers W are taken out from the cassette C by the first
transport arm mechanism 3 and then placed in the
transport-in/buffer mechanism 11. The wafers W are further
transferred to the second transport arm mechanism 8 from the
transport-in/buffer mechanism 11 and transported into the treatment
units 13 to 17 of the process section 6. In the cleaning unit 13,
wafers W are first cleaned by a treatment liquid mainly composed of
a first chemical liquid, then rinsed by pure water and then
spin-dried by a spin rotation. Then, in the cleaning unit 14, the
wafers are cleaned by a treatment liquid mainly composed of a
second chemical liquid which is different from the first chemical
liquid, then rinsed by pure water and then spin-dried by a spin
rotation. In the cleaning unit 15, the wafers W are subjected to a
final cleaning with pure water and then spin-dried by spin
rotation.
[0030] Then, a cleaning unit 13 will be described with reference to
FIGS. 2 to 6.
[0031] A transport in-/outlet 13b is provided in a side wall of a
chamber 13a. A shutter(not shown) is mounted to the
transport-in/outlet 13b and silicon wafers W are taken in or out of
the chamber 13a through the transport in-/outle 13b with the
shutter opened by the second transport arm mechanism 8. The wafers
W has a diameter of 8 inches or 12 inches and a V notch is formed
at a point on the periphery of each wafer.
[0032] In the chamber 13a, a drain cup 90 (not shown: see FIG. 12)
is disposed in a communication with an exhaust passage and a
drainage liquid passage. Rotary guide members 20a to 20e as a
substrate support section are vertically arranged at proper
intervals in the drain cup 90 and a wafer W is rotatably supported
by the rotary guide members 20a to 20e. Each of the five rotary
guide members 20a to 20e comprises: a vertical shaft 21; and a
rotary guide 22 mounted at the tip of the vertical shaft 21. The
rotary guide 22 has the shape of a frustum of right circular cone
with an upper diameter being smaller than a lower diameter and when
the rotary guides 22 support the wafer W, the slope of each rotary
guide 22 is put in contact with the circumferential portion of a
wafer W. The slop 23 of the rotary guide 22 is made from a soft
resin material so as not to hurt a wafer W. It is preferred that
the slop 23 is made from a resin material which is hard to produce
particles from itself.
[0033] A motor 24 is only required to be provided to at least one
of the rotary guide members 20a to 20e. In this embodiment, two
motors 24 are respectively attached to two rotary guide members
20a, 20c. The two motors 24 are controlled in a synchronized manner
by a controller 100. With such a synchronous rotation drive
adopted, the wafer W is rotated smoothly. In the mean time, the
other rotary guide members 20b, 20d, 20e are respectively supported
by bearings 25 in a freely rotatable manner.
[0034] The wafer W is transferred onto these rotary guide members
20a to 20e from the second transport arm mechanism 8. A step 8d is
formed in the holder 8a of the second transport arm mechanism, as
shown in FIG. 4 and the periphery of the wafer W is not only
supported by the step 8d, but the center of the wafer W is
automatically adjusted in position.
[0035] A first roll brush 31 is disposed above an upper surface
(front side surface) of the wafer W, while a second roll brush 32
is disposed under a lower surface (back side surface) of the wafer
W. The first and second roll brushes 31, 32 are made from soft
sponge and has a length a little longer than radius of the
wafer.
[0036] As shown in FIGS. 2 and 5, the first and second roll brushes
31, 32 are connected with rotary shafts of motors M1, M2 of a drive
mechanism 30 and rotate about horizontal axes thereof. The first
motor M1 is held by a support pole 33 with a support plate P1
interposed therebetween and the second motor M2 is held by a
support pole 33 with a support plate P2 interposed
therebetween.
[0037] The support pole 33 has two Z axis movement mechanisms (not
shown) in its interior and the first support plate P1 is raised or
lowered by one Z axis movement mechanism and the second support
plate P2 is raised or lowered by the other Z axis movement
mechanism. Besides, a pressure adjustment mechanism (not shown) is
also provided in the interior of the support pole 33. The pressure
adjustment mechanism works for fine control of a pressure on the
wafer W of the brushes 31, 32 whose distance is adjusted by the Z
axis movement mechanism. Such a pressure adjustment mechanism is
described in, for example U.S. Pat. No. 5,685,039.
[0038] A .theta. rotation drive section 35 is connected to the
lower end of the support pole 33 and the support pole 33 is
subjected to .theta. rotation about Z axis. When the support pole
33 is subjected to .theta. rotation, the roll brushes 31, 32 are
oscillated about the support pole 33 together with the .theta.
rotation. Besides, the .theta. rotation drive section 35 is mounted
on a X axis drive section 34 and the brushes 31, 32 are slidably
moved on a guide rail 34a along an X axis direction together with
the support pole 33. With such a drive mechanism 30 adopted, the
brushes 31, 32 reciprocate between working positions and home
positions.
[0039] As shown in FIG. 2, a brush cleaning vessel 38 is provided
at the home positions of the brushes 31, 32 and dirt (attached
foreign matter) of the brushes 31, 32 is removed therein. A supply
pipe 39 is provided in the brush cleaning vessel 38 and pure water
is supplied into the brush cleaning vessel 38 from a pure water
supply source (not shown) as a cleaning liquid. A drainage port
(not shown) is provided at the bottom of the brush cleaning vessel
38. The drainage port is communicated with a recovery/reproduction
system (not shown) for recovery and reproduction of drainage. The
brushes 31, 32 are inserted into the brush cleaning vessel 38 and
pure water is supplied therein through the supply pipe 39 while the
brushes 31, 32 are rotated, so that the brushes 31, 32 are cleaned.
In the mean time, since the brushes 31, 32 are provided with a
cleaning liquid supply passage in the interior thereof, the brushes
31, 32 may be cleaned while the cleaning liquid is discharged from
the interior of itself.
[0040] As shown in FIG. 4, the scrubbing apparatus of this
embodiment is equipped with four nozzles 41, 42, 51, 52. A first
main nozzle 41 and a first auxiliary nozzle 51 are disposed above
the wafer W in such a manner that both nozzles 41, 51 may not
interfere with each other. A second main nozzle 42 and a second
auxiliary nozzle 52 are disposed under the wafer W in such a manner
that both nozzles 42, 52 may not interfere with each other.
[0041] The first main nozzle 41 is attached to one end of an arm
43a and the other end of the arm 43a is connected to and supported
by a vertical shaft of a drive mechanism 43. When the arm 43a is
oscillated by the drive mechanism 43, the first main nozzle 41, as
shown in FIG. 2, moves to a working position (right above the
central region of the wafer W) from a home position. The first main
nozzle 41 is to clean a pattern region of the wafer W. On the other
hand, the second main nozzle 42 is attached to one end of an arm
44a and the other end of the arm 44a is connected to and supported
by a vertical shaft of a drive mechanism 44. The second main nozzle
42 virtually acts in the same way as the first main nozzle 41.
[0042] The first auxiliary nozzle 51 is attached to one end of an
arm 53a and the other end of the arm 53a is connected to and
supported by a vertical shaft of a drive mechanism 53. When the arm
53a is oscillated by the drive mechanism 53, the first auxiliary
nozzle 51, as shown in FIG. 2, moves to a working position (right
above a position on the peripheral region of the wafer W) from a
home position. The first auxiliary nozzle 52 is to clean a
non-pattern region of the wafer W. On the other hand, the second
main nozzle 52 is attached to one end of an arm 54a and the other
end of the arm 54a is connected to and supported by a vertical
shaft of a drive mechanism 54. The second auxiliary nozzle 52
virtually acts in the same way as the first auxiliary nozzle
51.
[0043] Then, the first main nozzle 41 as a representative of the
cleaning nozzles, will be described with reference to FIGS. 6 and
7.
[0044] The nozzle 41 is a so-called megasonic nozzle equipped with
an ultrasonic oscillator 59. A flow passage 56 of the nozzle 41 is
communicated with first and second liquid sources 101, 102 through
a change-over valve 103. The first liquid source 101 stores pure
water as a first cleaning liquid and the second liquid source 102
stores a chemical solution as a second cleaning liquid. The second
cleaning liquid is, for example, an APM liquid, a DHF liquid, an
HPM liquid or the like, which are used in RCA cleaning. The liquid
supply sources 101, 102 are respectively provided with flow rate
control valves which are controlled by a controller 100. A
change-over valve 103 is inserted in a cleaning liquid supply
circuit and its action is controlled by the controller 100. Supply
circuits from the first and second liquid sources 101, 102 are
changed over by the change-over valve 103 and the first or second
liquid is supplied into the nozzle flow passage 56. As the cleaning
liquids, for example, pure water is used after film formation,
while a chemical liquid is used after CPM polishing.
[0045] The nozzle body 55 is made from a resin with resistance to
chemicals and the ultrasonic oscillator 59 is mounted in the
vicinity of the tip. The ultrasonic oscillator 59 comprises: a
transducer 57 which is inserted in an annular recess 55a of the
nozzle body 55; a protective cover 58 surrounding the transducer
57; and a power source 104 for supplying a power to the transducer
57. The transducer 57 has a helical form and surrounds the flow
passage 56 in the vicinity of the tip of a liquid discharge port
56a. The protective cover 58 is made from stainless steel.
[0046] When the controller 100 sends an instruction signal to the
power source 104, electricity is supplied to the transducer 57 from
the power source 104 and ultrasonic waves with a frequency in the
range of from 1 to 2 MHz are emitted from the transducer 57. The
ultrasonic waves are applied on a cleaning liquid in the flow
passage 56 through the nozzle body 55. The cleaning liquid applied
with ultrasonic waves is discharged toward the wafer W from the
liquid discharge port 56a and acts on foreign matter attached on
the wafer W. An attaching force of the foreign matter is weaken by
the cleaning liquid, which accelerates separation of the foreign
matter from the wafer W.
[0047] Then, The case where both surfaces of the wafer W are
cleaned using the scrubbing apparatus with reference to FIGS. 2 to
7.
[0048] A shutter is opened while the roll brushes 31, 32; the main
nozzles 41, 42; and the auxiliary brushes 51, 52 are kept stand-by
in respective home positions, a wafer W is transported into the
chamber 13a by the second transport arm mechanism 8 and the wafer W
is transferred to the rotary guide members 20a to 20e, wherein the
wafer is already positioned in regard to a notch prior to
transportation into the chamber 13a.
[0049] Then, the wafer W is rotated by the rotary guide members 20a
to 20e and not only are the roll brushes 31, 32 respectively moved
to the working positions from the home positions, but the nozzles
41, 42, 51, 52 are respectively moved to the working positions from
the home positions. At first, a distance between the brushes 31, 32
is adjusted so as to be larger than the thickness of the wafer W
and after the brushes 31, 32 arrive at the working positions, the
pressure adjustment mechanism presses the roll brushes 31, 32 to
the front side and back side surfaces of the wafer W respectively
under a specific pressure. Generally speaking, a pressure of the
first brush 31 on the wafer front side surface (the pattern forming
surface) is lower than that of the second brush 32 on the wafer
back side surface (the non-pattern forming surface). The reason why
is not to give any damages on a circuit pattern.
[0050] Then, not only is the cleaning liquid supplied on the front
side and back side surfaces of the wafer W in the vicinity of the
rotation center thereof from the main nozzles 41, 42, but the
cleaning liquid is supplied on the front side and back side surface
along the peripheral region thereof from the auxiliary nozzles 51,
52. The roll brushes 31, 32 are moved so as to traverse from one
peripheral region of the wafer W to the other peripheral region
while being rotated. With such a traverse movement, the cleaning
liquid is diffused from the rotation center of the wafer W toward
the peripheral region. At this point, the cleaning liquids
discharged from the nozzles 41, 42, 51, 52 are applied with
ultrasonic waves.
[0051] As shown in FIG. 7, electricity supplied from the power
source 104 is controlled by the controller 100 and while the
cleaning liquid supplied from the main nozzle 41 is applied with
weaker ultrasonic waves, the cleaning liquid from the auxiliary
nozzle 51 is applied with stronger ultrasonic waves. For example,
when the central region of the wafer W is cleaned, ultrasonic
oscillation with a power as weak as a pattern does not receive any
damages by, for example ultrasonic oscillation with a power of 100
W, is given to the cleaning liquid, wherein the power source 104 is
not switched off, whereas, when the peripheral region of the wafer
W is cleaned, ultrasonic oscillation with a strong power, for
example ultrasonic oscillation with a power of 150 W is given to
the cleaning liquid. In this case, a higher cleaning power is given
to the peripheral region in the wafer W than to the central region,
whereby attached foreign object such as particles is sure to be
swiftly removed from the peripheral region of the wafer W. Besides,
the cleaning liquid which is applied with a strong ultrasonic power
by the auxiliary nozzle 51 is supplied toward the center along a
radius by 20 to 50 mm in width from the circumferential
portion.
[0052] Not only is the cleaning liquid applied with ultrasonic
waves supplied by the nozzles 41, 42, 51, 52 while the nozzles are
moved, but the brushes 31, 32 are reciprocated while the wafer W is
rotated. Thereby, the wafer W is cleaned thoroughly in every point
all over the wafer W from the central region to the peripheral
region. Especially, since the cleaning liquid supplied from the
auxiliary nozzle 42 is applied with high power ultrasonic waves
with a frequency of 1.8 MHz, there is no chance when the peripheral
region of the wafer W is short of cleaning. Such cleaning liquid
applied with ultrasonic waves can easily penetrate into a tiny gap
and therefore, the wafer W is thoroughly cleaned at every point
thereon. Hence, the cleaning liquid penetrates even at a site where
the roll brushes 31, 32 cannot contact, for example between the
rotary guide members 20a to 20e and the wafer W, and sufficiently
cleans every site on the wafer W by a cleaning accelerating action
of ultrasonic waves. Since the rotary guide members 20a to 20w and
the wafer W are rotated while changing relative position to each
other, contact positions between both are constantly interchanged
and thereby every portion on the wafer W is cleaned.
[0053] After the cleaning, the nozzles 41, 42, 51, 52 and the roll
brushes 31, 32 are returned to the respective home positions. Then,
the wafer W is rotated at a high speed by the rotary guide members
20a to 20e and the cleaning liquid on the wafer W is removed by
separation therefrom to dry the surfaces of the wafer W.
[0054] According to the apparatus of the embodiment described
above, a fine pattern in the central region of a wafer W does not
receive any damages, while the periphery of the wafer W can
sufficiently be cleaned with certainty.
[0055] Besides, according to the apparatus of the embodiment, since
the wafer W is supported by the rotary guide members 20a to 20e
only at the peripheral region, a large space can be available on
the back side surface of the wafer W and the brush 32, the main
nozzle 42 and the auxiliary nozzle 52 can also be provided on the
back side surface of the wafer W. The back side surface of the
wafer W can be cleaned by the brush 32, and the main and auxiliary
nozzles 42, 52 to the same cleanliness level as the front side
surface. For this reason, since both surfaces of a wafer W can be
cleaned without use of a conventional reversing device, which
enables not only downsizing of the apparatus but shortening of
cleaning time by a great margin and improvement in throughput.
[0056] While, in the embodiment, the case is described, where the
middle portion of a wafer W is subjected to weak cleaning using the
main nozzle 41 and the peripheral portion of the wafer W is
subjected to strong cleaning using the auxiliary nozzle 51, only
one nozzle may be used for cleaning by the ultrasonic wave not only
the middle portion of the wafer W but the peripheral portion as
well. In this case, the cleaning liquid applied with a weak power
ultrasonic waves is supplied in the central region of the wafer W
through the nozzle, while the cleaning liquid with a strong power
ultrasonic waves is supplied along the peripheral region through
the same nozzle.
[0057] The second embodiment of the present invention will be
described with reference to FIGS. 8 to 11.
[0058] In the embodiment, as shown in FIGS. 9 and 10, a wafer W is
held by a pair of support rings 60a, 60b, one on the other, as a
substrate support section, in such a manner that the
circumferential portion of the wafer W is pressed between support
rings 60a, 60b. The support ring 60a in the upper place is
connected to the support ring 61a in the upper place in a freely
rotatable manner through a plurality of ribs 62a and a plurality of
bearings 63b (see FIG. 11). A support ring 60b in the lower place
is connected to a support ring 61b in the lower in a freely
rotatable manner place through a plurality of ribs 62b and the
plurality of bearings 63b (see FIG. 11).
[0059] As shown in FIG. 8, the support ring 61a in the upper place
is connected to and held by an arm 64a of a vertically shiftable
mechanism 64. When the support ring 60a in the upper place is
lowered together with the support ring 61a, a protrusion 60p
downward protruding from the support ring 60a is fit into a recess
of the support ring 60b in the lower place and not only are the
support rings 60a, 60b in the upper and lower places connected with
each other, but the wafer W is pressed between both support rings
60a, 60b. Inside diameters of the support rings 60a, 60b in the
upper and lower places are a little smaller than that of the wafer
W.
[0060] A belt 67 is wound over the periphery of the support ring
60b in the lower place and a rotation drive force of a motor 66 is
transmitted to the support ring 60b through the belt 67. Here, the
motor 66 and the support ring 61b in the lower place are fast held
to the base 65.
[0061] As shown in FIG. 10, the periphery of the wafer W is put in
contact with an inward inclined slope 60c of the support ring 60a
in the upper place and an inward inclined slope 60c of the support
ring 60b in the lower place and in this condition, the wafer W is
horizontally held by both support rings 60a, 60b.
[0062] As shown in FIG. 11, the fore end of a connecting rib 62b
(62a) is in the sectional shape of a letter T and the fore end is
mounted to the support ring 60b in the lower place with a bearing
63b interposed therebetween. With this structure, the support ring
60b in the lower place can move relatively to the connecting rib
62b and the support ring 61b. In a similar manner, the support ring
60a in the upper place can move relatively to the connecting rib
62a and the support ring 61a.
[0063] As shown in FIG. 9, a table 68 is provided under the base
65. The table 68 can move between a stand-by position under the
base 65 and a reception/transfer position under the wafer W by
rotation mechanism 69 mounted on the lower surface of the base
65.
[0064] A first disk brush 71 is mounted to the fore end of an arm
73 of a drive mechanism 75 and opposed to the front side surface
(upper surface) of the wafer W. A second disc brush 72 is mounted
to the fore end of an arm 74 of the drive mechanism 75 and opposed
to the back side surface (lower surface) of the wafer W. Brush
rotation mechanisms (not shown) are respectively provided inside
the arms 73, 74 and the brushes 71, 72 are rotated about respective
vertical axes by drive of both mechanisms. Besides, the arms 73, 74
are supported in a movable manner along horizontal directions by
the drive mechanism 75.
[0065] In the embodiment, working positions of the first main
nozzle 41 and the first auxiliary nozzle 51 are above the support
ring 61a in the upper place and working positions of the second
main nozzle 42 and the second auxiliary nozzle 52 are under the
support ring 61b in the lower place.
[0066] Then, actions of a scrubbing apparatus of the embodiment
will be described.
[0067] The support ring 60a in the upper place is raised and a
wafer W is inserted in between the support rings 60a, 60b, while
the brushes 71, 72 and nozzles 41, 42, 51, 52 are kept in a
stand-by position at respective home positions. Then, the table 68
is moved to the reception/transfer position, a plurality of pins
68b are protruded from the upper surface of the table 68 and the
wafer W is transferred on the pins 68a. Then, the pins 68a are
retreated into the table 68 and the wafer W is further moved on the
support ring 60b in the lower place. The support ring 60a in the
upper place is lowered to a working position, the support rings
60a, 60b are coupled with each other and the wafer W is thus held.
Thereafter, the table 68 is lowered to its home position.
[0068] Then, the support ring 60b in the lower place is given a
rotation force and the wafer W is rotated together with the support
rings 60a, 60b. On the other hand, not only are the brushes 71, 72
moved toward above the wafer W but the nozzles 41, 42, 51, 52 are
respectively moved to working positions from home positions. Then,
not only is the cleaning liquid is supplied from the main nozzles
41, 42 to the rotation center of the wafer W but the cleaning
liquid is supplied to the peripheral region of the wafer W from the
auxiliary nozzles 51, 52. The brushes 71, 72 are respectively put
into contact with the front side and back side surfaces of the
wafer W under specific pressures while the cleaning liquid applied
with ultrasonic oscillation is supplied and the brushes 71, 72 are
reciprocated from one peripheral region of the wafer W to the other
peripheral region while being rotated.
[0069] Then, the third embodiment of the present invention will be
described with reference to FIGS. 12 and 13.
[0070] In the embodiment, a mechanical chuck 80 is used as a
substrate support section. The mechanical chuck 80 is provided
inside a drain cup 90. The drain cup 90 is provided with a movable
cup portion 90a and a fixed cup portion 90b. The movable cup 90a is
connected to a rod 98a of a cylinder 98 through openings 90c, 90f
of the fixed cup portion 90b. When the rod 98a gets protruded from
the cylinder 98, the movable cup 90a is raised and to the contrary,
when the rod 98a gets retreated into the cylinder 98, the movable
cup 90a is lowered.
[0071] A rotary drive shaft 83a of a motor 83 penetrates a central
projection 90g of the fixed cup portion 90b and connected to the
bottom plate 81 of the mechanical chuck 80. A seal bearing 90h is
provided between the rotary drive shaft 83a and the central
projection 90g. A plurality of drain holes 90d are formed in the
fixed cup portion 90b at proper positions thereof and cleaning
drainage is discharged through the drain holes 90d outside the cup
80.
[0072] The bottom plate 81 of the mechanical chuck 80 has almost
the same size as the diameter of the wafer W. Six erect portions 84
are provided along the periphery of the bottom plate 81 and wafer
support sections 85 are respectively provided on the erect portions
84. An inner surface of a wafer support section 85 is inward
inclined in the lower portion starting at a position half a depth
and the periphery of the wafer W is put in contact with the upper
side of the inward inclined slope. Each of the wafer support
sections 85 is mounted on an erect portion 84 with a horizontal
shaft 86 interposed therebetween. Besides a weight not shown is
included in a wafer support section 85.
[0073] The wafer W is transferred to the mechanical chuck 80 by a
transport arm 87 shown in FIG. 13. The transport arm 87 has a
ring-like form without an arc portion whose inner diameter is
larger than that of the bottom plate 81 and has wafer placing
strips 88 extending inward from three positions on inner side of
the ring form. The wafer W is placed on projections 88a formed at
the fore end of the wafer placing strip 88.
[0074] Cut-aways 81a through which the wafer placing strips 88 can
pass are formed at positions of the bottom plate 81 corresponding
to the wafer placing strips 88. The wafer W held on the transport
arm 87 is moved to a specific position above the mechanical chuck
80, thereafter the transport arm 87 is lowered while allowing the
wafer placing strips 88 to pass through the cur-aways 81a and
thereby the wafer W is transferred to the wafer support section 85
of the mechanical chuck 80.
[0075] The disk brush 91 is movably supported by a movement
mechanism (not shown) through an arm 91a. A main nozzle 92 is
movably supported by a movement mechanism (not shown) through an
arm 92a. Besides, an auxiliary nozzle 93 is movably supported by a
movement mechanism (not shown) through an arm 93a. The brush 91 and
the nozzles 92, 93 are moved to working positions from home
positions by the movement mechanisms and the wafer W which is held
by the mechanical chuck 80 is opposed to the brush 91 and the
nozzles 92, 93. In this case, the main nozzle 92 is disposed right
above the central region of the wafer W and the auxiliary nozzle 93
is disposed right above the peripheral region of the wafer W. The
main and auxiliary nozzles 92, 93 are equipped with ultrasonic wave
oscillator 59 as in the above described cases.
[0076] In the scrubbing apparatus with such a construction, not
only the cleaning liquid is supplied in the central region of a
wafer W from the main nozzle 92 while the wafer W is rotated by the
mechanical chuck 80, but the cleaning liquid applied with
ultrasonic waves is supplied along the peripheral region of the
wafer W from the auxiliary nozzle 93. Scrubbing is progressed while
the brush 91 is rotated and moved across the wafer W.
[0077] When a centrifugal force acts on the wafer support sections
85, the upper portion is inward inclined under influence of the
weight and the brush 91 is prevented from advancing up to a
position very close to the wafer periphery in the spots where the
wafer support sections 85 are provided. However, the cleaning
liquid applied with ultrasonic waves from the auxiliary nozzle 93
penetrates through gaps between the wafer support sections 85 and
the wafer periphery and as a result, the cleaning liquid can reach
every point all over the peripheral region and the circumferential
portion of the wafer W. Hence, the peripheral region and the
circumferential portion of the wafer W are cleaned and thereby, not
only the central region but the peripheral region of the wafer W
can be cleaned.
[0078] A method may also be employed in which a position of the
wafer where the cleaning liquid is dropped is irradiated with
ultrasonic waves and thereby the cleaning liquid is vibrated. There
is no limitation to a method in which the main nozzles 41, 42
supplies the cleaning liquid to almost the rotation center of the
wafer W, but the main nozzles 41, 42 can be moved between the
peripheral region and the rotation center. The auxiliary nozzles
51, 52 may supply the cleaning liquid to any region on the wafer,
as long as the auxiliary nozzles 51, 52 directs the cleaning liquid
to a region outside the pattern forming region. Besides, a method
may also employed in which the main nozzles 41, 42 are constructed
from a megasonic nozzle as in the case of the auxiliary nozzles 51,
52 and ultrasonic waves with a power as weak as a pattern does not
receive any damages by is given to the cleaning liquid and the
central region of the wafer W is cleaned with the cleaning liquid
through the main nozzles 41, 42.
[0079] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
* * * * *