U.S. patent application number 11/042199 was filed with the patent office on 2005-06-16 for substrate processing method and substrate processing apparatus.
This patent application is currently assigned to TOKYO ELECTRON LIMITED. Invention is credited to Kitano, Junichi, Matsui, Hidefumi.
Application Number | 20050130445 11/042199 |
Document ID | / |
Family ID | 19169405 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050130445 |
Kind Code |
A1 |
Matsui, Hidefumi ; et
al. |
June 16, 2005 |
Substrate processing method and substrate processing apparatus
Abstract
The wafer coated with the resist is deliberately placed in the
vapor before being transferred to an aligner that exposes the
resist on the wafer, the vapor, for example, the moisture,
uniformly adheres onto the resist on the wafer. As a result, the
substrate can uniformly be exposed in the following exposing
process, and the uniformity of the line width and the like can be
improved.
Inventors: |
Matsui, Hidefumi;
(Nirasaki-Shi, JP) ; Kitano, Junichi;
(Nirasaki-Shi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
TOKYO ELECTRON LIMITED
Tokyo-To
JP
|
Family ID: |
19169405 |
Appl. No.: |
11/042199 |
Filed: |
January 26, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11042199 |
Jan 26, 2005 |
|
|
|
10300760 |
Nov 21, 2002 |
|
|
|
6875466 |
|
|
|
|
Current U.S.
Class: |
438/780 ;
118/715; 438/164 |
Current CPC
Class: |
H01L 21/67178 20130101;
H01L 21/67751 20130101; H01L 21/67748 20130101 |
Class at
Publication: |
438/780 ;
438/164; 118/715 |
International
Class: |
H01L 021/00; H01L
021/84; C23C 016/00; H01L 021/31; H01L 021/469 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 22, 2001 |
JP |
2001-358183 |
Claims
1-9. (canceled)
10. An apparatus for processing a substrate, comprising: a coating
processing portion coating a resist on the substrate; a vapor
processing portion placing the substrate coated with the resist in
an atmosphere including a vapor; and a transfer mechanism
transferring the substrate at least between the coating processing
portion and the vapor processing portion.
11. The apparatus as set forth in claim 10, wherein the vapor
processing portion places the substrate coated with the resist in a
saturated vapor atmosphere.
12. The apparatus as set forth in claim 10, further comprising: a
drying processing portion drying the substrate so that a moisture
adheres to a surface of the substrate remains thereon.
13. The apparatus as set forth in claim 12, wherein the drying
processing portion has a heating plate heating the substrate.
14. The apparatus as set forth in claim 12, wherein the drying
processing portion has means for supplying the substrate with a
heating air.
15. The apparatus as set forth in claim 10, wherein the apparatus
is disposed adjacent to an aligner, the apparatus further
comprising: a delivering and receiving portion delivering and
receiving the substrate between the vapor processing portion and
the aligner.
16. The apparatus as set forth in claim 12, wherein the apparatus
is disposed adjacent to an aligner, the apparatus further
comprising: a delivering and receiving portion delivering and
receiving the substrate between the drying processing portion and
the aligner.
17. The apparatus as set forth in claim 10, wherein the vapor
processing portion has a pressure controlling portion controlling a
pressure of the atmosphere around the substrate.
18. The apparatus as set forth in claim 17, wherein the pressure
controlling portion controls the pressure so that the pressure
becomes higher than an atmospheric pressure for a predetermined
time period beginning from when the substrate is started to be
placed in the vapor and controls the pressure so that the pressure
becomes lower than the atmospheric pressure after the predetermined
time period.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a substrate processing
apparatus for coating a semiconductor wafer with a resist and
developing thereof in a fabrication of semiconductor device. In
detail, the invention relates to a substrate processing apparatus
that controls the atmosphere of the processing environment of the
substrate.
[0003] 2. Description of the Related Art
[0004] In a process of photolithography in the semiconductor device
fabrication, the surface of a semiconductor wafer (hereinafter
referred to as "a wafer") is coated with a photo-resist, exposing a
mask pattern on the resist, then developing thereof, forming a
resist pattern on the wafer surface. The resist coating and
development are performed in an integrated coating and developing
processing apparatus including a thermal processing apparatus such
as a heating processing apparatus or a cooling processing
apparatus. The coating and developing apparatus is connected to the
aligner through an interface portion and the semiconductor device
fabrication is actually performed.
[0005] In the coating and developing apparatus, when processing of
wafer is performed, in order to prevent impurity such as particles
from adhering to the wafer, the air cleaned with an air cleaner is
supplied to the inside of the coating and developing processing
apparatus as a down flow of air current, so that the wafer is
processed in the clean condition.
[0006] However, these days, laser-beam light source with a short
wavelength like, for example, F.sub.2 excimer laser (157 nm) is
used in an aligner to cope with the miniaturization of the devices,
therefore in case that impurities of molecule level, which had not
been a problem up to now, such as oxygen, ozone, water and organic
matter, adheres on the resist film coated on the wafer in the steps
performed before the exposure, absorption and scattering of light
caused by the impurities tend to occur. When moisture adheres on
the resist film, 2% of the light will be absorbed with film
thickness of every 10 .ANG. (1 mm), and when the water molecules
exist scattering on the wafer surface, difference arises in amount
of exposure between the portion with water molecules and the
portion without the water molecules which causes deterioration in
the uniformity of line width of the pattern. The down flow of the
air described above is not able to remove the impurities of
molecule level.
SUMMARY OF THE INVENTION
[0007] Considering the above-described circumstances, an object of
the present invention is to provide a substrate processing method
and substrate processing apparatus that improves the uniformity of
line width even under a circumstance in which the impurities of
molecule level exists.
[0008] To accomplish the above-described objects, the substrate
processing method of the present invention comprises the steps of
(a) coating a resist on the substrate and (b) placing the substrate
coated with the resist in an atmosphere including a vapor.
According to the aforesaid structure, for example, the vapor, such
as water vapor uniformly adheres to the resist on the substrate by
deliberately placing the substrate into the vapor before
transferring thereof to an aligner that exposes the resist coated
on the substrate. Therefore, the substrate could uniformly be
exposed in the following exposing step, and the uniformity of the
line width can be improved. Here, in order to have the moisture
adhere uniformly on the substrate, a saturated vapor is preferably
used in this case.
[0009] Another embodiment of the present invention further
comprises the steps of (c) drying the substrate after the step (b)
so that moisture adhered to the substrate remains on the surface of
the substrate. In such manner, the moisture once adhered uniformly
on the substrate is decreased by performing drying process
uniformly so that the moisture adhered onto the surface of the
substrate remains thereon. With this method, exposing process can
be performed appropriately, thus the amount of exposure reaching
the resist can be increased as much as possible while keeping the
amount of exposure in the exposing step constant. In this case, in
order to perform drying process uniformly on the substrate, heating
the substrate is preferable as a drying process and the moisture
adhered on the substrate to be evaporated uniformly. Alternatively,
drying may be performed with supplying heating air uniformly all
over the substrate.
[0010] According to another embodiment of the present invention,
the step (b) has a step of controlling a pressure of the atmosphere
around the substrate. The amount of evaporating moisture adhered on
the substrate placed in the vapor can be controlled by controlling
the pressure. Especially, another embodiment of the present
invention is that the step (d) has the step of controlling the
pressure so that the pressure becomes higher than an atmospheric
pressure for a predetermined time period beginning from when the
substrate is started to be placed in the vapor and the step of
controlling the pressure so that the pressure becomes lower than
the atmospheric pressure after the predetermined time period. As a
result, the amount of moisture evaporate from the substrate can be
restrained beginning from when the substrate is started to be
placed in the vapor until the predetermined time passes, which
causes acceleration in the effect of adhering moisture uniformly on
the substrate. In addition, after the predetermined time, the
moisture adhered onto the surface of the substrate is evaporated
actively, for example, the substrate is subjected to the uniform
drying process so that the moisture on the surface of the substrate
is decreased to a predetermined amount. With this embodiment, the
amount of exposure reaching the resist can be increased as much as
possible while keeping the amount of exposure in the exposing step
constant.
[0011] A substrate processing apparatus of the present invention
comprises, a coating processing portion coating a resist on the
substrate, a vapor processing portion placing the substrate coated
with the resist in an atmosphere including a vapor and a transfer
mechanism transferring the substrate at least between the coating
processing portion and the vapor processing portion.
[0012] According to the aforesaid structure, the substrate is, for
example, transferred to the vapor processing portion with the
transfer mechanism before delivering thereof to the aligner that
exposes the resist coated on the substrate. The vapor such as water
vapor uniformly adheres to the resist on the substrate by
deliberately placing the substrate therein. Therefore, the
substrate could uniformly be exposed in the following exposing
process, and the uniformity of the line width and the like can be
improved. In order to have moisture uniformly adhere on the
substrate, the vapor used in this case is preferred to be a
saturated vapor.
[0013] Another embodiment of the present invention further
comprises a drying processing portion drying the substrate so that
the moisture adheres to a surface of the substrate remains thereon.
The amount of moisture adhered uniformly on the substrate is
decreased so that the moisture adhered on the surface of the
substrate remains thereon in the drying processing portion of this
kind. With this method, exposing process can be performed
appropriately, thus the amount of exposure reaching the resist can
be increased as much as possible while keeping the amount of
exposure in the exposing step constant. In this case, in order to
perform drying process uniformly on the substrate, drying by
heating the substrate with a heating plate to have the moisture
adhered to the substrate evaporate uniformly is preferable.
Alternatively, drying can be performed with supplying heated air
uniformly all over the substrate. Furthermore, the drying
processing portion may be provided inside the vapor processing
portion. Alternatively, the drying processing portion can be
provided outside the vapor processing portion, and the substrate
may be transferred between the vapor processing portion and the
drying processing portion with, for example, the transfer
mechanism.
[0014] According to another embodiment of the present invention,
the vapor processing portion has a pressure controlling portion
controlling a pressure of the atmosphere around the substrate.
Especially the pressure controlling portion is preferred to control
the pressure so that the pressure becomes higher than an
atmospheric pressure for a predetermined time period beginning from
when the substrate is started to be placed in the vapor and control
the pressure so that the pressure becomes lower than the
atmospheric pressure after the predetermined time period.
[0015] These and other objects, features and advantages of the
present invention will become more apparent in light of the
following detailed description of a best mode embodiment thereof,
as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a plan view of a coating and developing processing
apparatus according to a first embodiment of the present
invention.
[0017] FIG. 2 is a front view of the coating and developing
processing apparatus shown in FIG. 1.
[0018] FIG. 3 is a rear view of the coating and developing
processing apparatus shown in FIG. 1.
[0019] FIG. 4 is a sectional view of a vapor processing unit
relating to the first embodiment of the present invention.
[0020] FIG. 5 is a flow chart showing a series of processing steps
of the coating and developing processing apparatus.
[0021] FIG. 6 is a sectional view of the vapor processing unit
relating to the second embodiment of the present invention.
[0022] FIG. 7 is a sectional view of the vapor processing unit
relating to the third embodiment of the present invention.
[0023] FIG. 8 is a sectional view, showing the case when the
heating process is performed in the vapor processing unit shown in
FIG. 7.
[0024] FIG. 9 is a sectional view of a vapor processing unit
according to the fourth embodiment of the present invention.
[0025] FIG. 10 is a perspective view of the unit supplying
ultra-pure water or vapor from the nozzle by roating the
substrate.
[0026] FIG. 11 is a sectional view of a vapor processing unit
according to the fifth embodiment of the present invention.
[0027] FIG. 12 is a sectional view of a vapor processing unit
according to the sixth embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] Preferred embodiments of the present invention will be
explained below with reference to the drawings.
[0029] FIG. 1, FIG. 2 and FIG. 3 are diagrams showing a total
configuration of a coating and developing processing apparatus
according to an embodiment of the present invention. FIG. 1 is a
plan view, FIG. 2 is a front view, and FIG. 3 is a rear view.
[0030] The coating and developing processing apparatus 1 has a
structure in which a cassette station 10 provided for carrying a
plurality of, for example, twenty-five semiconductor wafers W as
substrates to be processed in a wafer cassette CR, as a unit, to
the inside the apparatus 1 and carrying thereof to the outside of
the apparatus 1 and also carrying in the substrates from the wafer
cassette CR and carrying out the substrates from the cassette CR; a
processing station 11 in which various kinds of processing units
each for performing predetermined process for the semiconductor
wafers W one by one in coating and developing processing steps that
are multi-tiered; and an interface portion 12 for delivering and
receiving the semiconductor wafer W with an aligner 13 disposed
adjacent to the processing station 11, are integrally
connected.
[0031] In the cassette station 10, as shown in FIG. 1, a plurality
of, for example, up to four cassettes CR are placed in a line of an
X-direction at positions of projections 20a provided for alignment
thereof on a cassette mounting table 20, with respective outlet and
inlet ports for the wafer W facing the processing station 11. A
wafer transfer mechanism 21 movable in the direction of arrangement
of the cassettes (an X-direction) and in the direction of
arrangement of the wafers housed in the wafer cassette CR (a
Z-direction) is structured to be selectively accessible to each of
the wafer cassettes CR. Further, the wafer transfer mechanism 21 is
structured so that it can be rotated in .theta.-direction so as to
be accessible to a transfer and alignment unit (ALIM) and an
extension unit (EXT) included in a multi-tiered unit portion of a
third unit group G3 disposed at the processing station 11 side, as
will be described later.
[0032] In the processing station 11, as shown in FIG. 1, a vertical
carrier type of a main wafer transfer mechanism 22 is provided at a
center, around which a group of or a plurality of groups of all
processing units are multi-tiered. In this example, five processing
unit groups G1, G2, G3, G4 and G5 are disposed multi-tiered. The
multi-tiered units of the first and the second unit groups G1 and
G2 are disposed on the front side of the apparatus adjacent with
each other (the front in FIG. 1). The multi-tiered unit of the
third unit group G3 is disposed adjacent to the cassette station 10
and the multi-tiered unit of the fourth unit group G4 is disposed
adjacent to the interface portion 12. The multi-tiered unit of the
fifth unit group G5 is disposed on the back side In addition, the
fifth unit group G5 is structured to be movable along the rail 25
for maintenance of the main wafer transfer mechanism 22.
[0033] As shown in FIG. 3, the main wafer transfer mechanism 22 has
a wafer transfer device 46 that is capable of moving up and down in
vertical direction (the Z-direction) inside a cylindrical supporter
49. The cylindrical supporter 49 is connected to a rotating shaft
of a motor (not shown) and rotates integrally with the wafer
transfer device 46 around the aforesaid rotating shaft by a
rotational driving force of the motor. Thereby the wafer transfer
device 46 can be rotated in .theta.-direction. The wafer transfer
device 46 has, for example, three pairs of tweezers 48 moving
forwards and backwards on a pedestal 47. The tweezers 48 holds and
transfers the wafer.
[0034] As shown in FIG. 2, in the first unit group G1, two
spinner-type processing units for performing predetermined
processing while the wafer W is placed on a spin chuck in a cup CP,
for example, a resist coating unit (COT) and a developing
processing unit (DEV) are two-tiered from the bottom in order. Also
in the second unit group G2, two spinner-type processing units, for
example, the resist coating unit (COT) and the developing
processing unit (DEV) are two-tiered from the bottom in order.
Since the drainage of a resist solution is troublesome in terms of
both mechanism and maintenance in the resist coating processing
unit (COT), it is preferable to place the resist coating unit at
the lower tier. However, it is possible to place thereof on the
upper tier as necessary.
[0035] As shown in FIG. 3, in the third unit group G3, oven-type
processing units each for performing predetermined processing while
the wafer W is placed on a mounting table, for example, a cooling
unit (COL), an adhesion unit (AD) an alignment unit (ALIM), an
extension unit (EXT), a pre-baking unit (PAB), a post-baking unit
(POB) are stacked from the bottom in order. Also in the fourth unit
group G4, oven-type processing units, for example, two cooling
units (COL), an extension and cooling unit (EXTCOL), an extension
unit (EXT), a pre-baking unit (PAB) and a post-baking unit (POB)
are stacked from the bottom in order.
[0036] By disposing the cooling unit (COL) and the extension unit
(EXT), processing units with low processing temperature on the
lower tier and disposing the baking unit (PAB) and the post-baking
unit (POB), processing units with high processing temperature on
the upper tier, thermal interference between the units can be
reduced. However, it is also possible to dispose multi-tiered at
random.
[0037] The interface portion 12 has the same size as the processing
station 11 in the depth direction, but smaller in the width
direction. A portable pickup cassette CR and a fixed-type buffer
cassette BR are disposed in two tiers at the front of the interface
portion 12. A vapor processing unit 30, according to the present
invention is disposed at the back. In the center, a wafer transfer
mechanism 24 is disposed. The wafer transfer mechanism 24 moves in
the X- and the Z-direction to get access to both cassettes CR and
BR, and the vapor processing unit 30. The vapor processing unit 30
will be described later. The wafer transfer mechanism 24 is
structured so that it can be rotated in .theta.-direction so as to
be accessible to the extension unit (EXT) disposed in a
multi-tiered unit portion of the fourth unit group G4 disposed at
the processing station 11 side and to a transferring table (not
illustrated) adjacent to the aligner 13 side.
[0038] As shown in FIG. 1, the interface portion 12 is surrounded
by a wall member 15, and isolated from the outside atmosphere of
the coating and developing processing apparatus 1. With this
configuration, for example, inside of the interface portion 12
surrounded by the wall member 15 is purged with nitrogen gas or
heating air to regulate oxygen concentration and humidity (moisture
content) to low level. For example, the oxygen concentration is
adjusted to be 1 ppm and moisture content to be 1 ppm. Further,
openings 15a and 15b transferring the wafer W to the processing
station 11 and to the aligner 13 respectively, are formed on the
wall member 15 and the openings are structured to be able to open
and close by a shutter (not shown) In such manner, by controlling
the atmosphere inside the interface portion 12 precisely,
impurities such as oxygen and moisture adhering to the wafer right
before the exposing process with the aligner 13 can be
prevented.
[0039] FIG. 4 is a sectional view of the vapor processing unit 30
relating to the above-mentioned first embodiment. In this vapor
processing unit 30, for example, on an upper portion of
cylindrically shaped holding table 34, provided for holding the
wafer W, for example, a cylindrically shaped lid 32 is disposed. A
lifting mechanism 26 configured of an air cylinder enables the lid
32 to be lifted and lowered. An O-ring for seal is attached to the
lower end of the lid 32. When the lid 32 is lowered by the lifting
mechanism 26, a processing chamber R is formed as the lower end
portion thereof touches the holding table 34.
[0040] A plurality of holes 34a, for example three, pierces through
the holding table 34. Three Support pins 29 supporting the wafer W
from the back side are provided and a lifting cylinder 36 enables
the support pins 29 to protrude and sink to the surface of the
holding table 34 through the holes 34a. Thereby, the wafer W can be
delivered to and received from the wafer transfer mechanism 24.
[0041] In addition, around the edge portion of the holding table
34, a plurality of supply ports 34b supplying vapor into the
processing chamber R are provided. The vapor, for example, is
supplied from a vapor generator 35 through a supply pipe 38 with a
pump 28. The vapor generator 35 vaporizes, for example, ultra-pure
water 39 by heating thereof with a heater 37. At the supply pipe
38, a regulating valve 27 regulating pressure and flow rate of the
vapor is provided.
[0042] Inside the lid 32, a sensor 33 measuring humidity inside the
processing chamber R is provided. The amount of vapor supplied can
be controlled corresponding to, for example, the measuring result
of the sensor 33.
[0043] A series of processing steps in the coating and developing
processing apparatus 1 explained above will be explained with
reference to the flow chart shown in FIG. 5.
[0044] First, in the cassette station 10, the wafer transfer
mechanism 21 gets access to the cassette CR on the cassette
mounting table 20, housing unprocessed wafers and takes one wafer W
out of the cassette CR and transfers to the alignment unit (ALIM).
After the alignment unit (ALIM) aligns the wafer W (step 1), the
wafer W is transferred to the adhesion unit (AD) with the main
wafer transfer mechanism 22 where hydrophobic process is performed
(step 2) then to the cooling unit (COL) where a predetermined
cooling process is performed (step 3). Thereafter, the wafer is
transferred to the resist coating processing unit (COT) and the
resist is spin coated thereon (step 4). Then a predetermined
heating process is performed in the pre-baking unit (PAB) (step 5)
followed by cooling process in the cooling unit (COL) (step 6).
After that, in the interface portion 12, the wafer is transferred
to the vapor processing unit 30 with the wafer transfer mechanism
24.
[0045] In the vapor processing unit 30, the wafer W is delivered to
the supporting pins 29 on the holding table 34, and as the
supporting pins 29 lowers, the wafer W is placed on the holding
table 34 while the lid 32 is in its upper position. Then the lid 32
is lowered and the processing chamber R is formed (FIG. 4). Next,
the vapor is supplied into the processing chamber R from the vapor
generator 35 and the vapor is uniformly adhered to the front
surface of the resist film. With this configuration, the wafer can
uniformly be exposed in the following exposing process and the
uniformity of the line width can be improved (step 7).
[0046] In other words, according to the present embodiment, the
amount of exposure reaching to the resist decreases as the vapor
uniformly adheres on the resist, however, the wafer can uniformly
be exposed compared with the prior art where the moisture exists
scattered on the wafer. The decrease in the amount of exposure can
be prevented with raising the intensity of the exposure. Also,
regarding the supply of the vapor, it is preferable to have the
processing chamber R saturated with vapor. In other words, the
saturation causes the humidity to be approximately 100%, amount of
moisture is increased as much as possible, thereby enabling the
vapor to adhere more uniformly on the wafer. The second and the
following embodiments described below also carry out vapor
processing with the saturated vapor. However, it is not always
necessary to process in the saturated state.
[0047] The wafer transfer mechanism 24 transfers the wafer W to the
aligner 13 and the exposing process is performed therein (step 7).
After the exposing process, the heating process in the post
exposure baking unit (PEB) is performed (step 8). After that, the
wafer W is transferred to the developing processing unit (DEV) and
the developing process is performed (step 9). Then the
predetermined heating process is performed in the post-baking unit
(POB) (step 10). Thereafter the wafer W is subjected to a
predetermined cooling process in the cooling unit (COL) (step 11),
and returned to the cassette CR through the extension unit
(EXT).
[0048] FIG. 6 is a sectional view showing a vapor processing unit
according to the second embodiment of the present invention.
Incidentally in FIG. 6, the same numerals and symbols will be used
to designate the same components as those in FIG. 4, and the
explanation thereof will be omitted. A heating plate 43 heating the
wafer W by placing the wafer W thereon is disposed on the holding
table 41 in the vapor processing unit 40. The heating plate 43 has,
for example, a heater 45 and the wafer W is heated thereby. On the
heating plate 43, three holes 43a are formed and the supporting
pins 29 protrude and sink therethrough. With such configuration,
the wafer W can be delivered and received from the outside.
Meanwhile, a supply port 41a for supplying the vapor from the vapor
generator 35 into the processing chamber R is formed on the holding
table 41.
[0049] With regard to the processing steps of the vapor processing
unit 40, first of all, the wafer W is placed on the heating plate
43 and the lid 32 is lowered to form the processing chamber R.
Then, the vapor is supplied into the processing chamber R from the
vapor generator 35 and adhered uniformly onto the front surface of
the resist film. With this structure, the wafer can uniformly be
exposed in the following exposing process and the uniformity of the
line width and the like can be improved.
[0050] Next, the wafer W is heated with the heating plate 43 at a
predetermined temperature for a predetermined time period. With
this method, the moisture adhered on the wafer W can be evaporated
so that the moisture remains on the surface of the wafer W. In such
manner, the moisture adhered uniformly on the substrate is
decreased by heating the wafer W uniformly so that the moisture
adhered to the surface thereof remains thereon, in other words, the
drying process is being performed to the wafer W. This enables the
exposing process to be performed appropriately, thus the amount of
exposure reaching the resist can be increased as much as possible
while keeping the amount of exposure in the exposing step
constant.
[0051] FIG. 7 is a sectional view showing a vapor processing unit
according to the third embodiment of the present invention.
Incidentally in FIG. 7, the same numerals and symbols will be used
to designate the same components as those in FIG. 4, and the
explanation thereof will be omitted. A similar apparatus to the
vapor processing unit in FIG. 4 is disposed inside the case 44 in
the vapor processing unit 50. A transferring body 52 moving
horizontally along with a rail 42 with the cylinder mechanism or a
belt mechanism is disposed adjacent to the apparatus. A heating
plate 43 supported by the supporting plate 51 is provided on the
transferring body 52. In addition, according to the embodiment, a
supply port 32a is formed at the side portion of the lid 32, as
illustrated, and the vapor from the vapor generator 35 is supplied
into the processing chamber R through the supply port 32a In the
case 44 an opening 44a is provided for delivering the wafer W to
and receiving the wafer W from the outside.
[0052] With regard to the processing steps of the vapor processing
unit 50, first of all, when the wafer W is placed on the holding
table 34 with the holding pins 29, the lid 32 lowers to form the
processing chamber R. Then, the vapor is supplied into the
processing chamber R from the vapor generator 35 and uniformly
adheres on the surface of the resist film on the wafer. In such
manner, the wafer can uniformly be exposed in the following
exposing process and the uniformity of the line width and the like
can be improved.
[0053] Next, as shown in FIG. 8, the lid 32 rises and the
transferring body 52 approaches. Then the heating plate 43 moves to
right above the wafer W and stops subjecting the wafer W to the
heating process at a predetermined temperature for a predetermined
time period. In such manner, similar to the second embodiment
described above, the moisture adhered on the wafer W can be
evaporated so that the moisture remains on the surface thereof.
This causes the exposing process to be performed appropriately,
thus the amount of exposure reaching the resist can be increased as
much as possible while keeping the amount of the exposure in the
exposing step constant.
[0054] FIG. 9 is a sectional view showing a vapor processing unit
according to the fourth embodiment of the present invention.
Incidentally, in FIG. 9, the same numerals and symbols will be used
to designate the same components as those in FIG. 4, and the
explanation thereof will be omitted. In the central portion of the
lid 32 in the vapor processing unit 60, an air supply port 32b is
formed for supplying air into the processing chamber R from the air
supply source 54 through a supply pipe 57. The air from the air
supply source 54 is supplied heated, for example, with a heater 55
to a predetermined temperature, for example, 50.degree. C. to
100.degree. C. On the inside ceiling of the lid 32, a defusing
member 56 is attached for defusing the air supplied as above
uniformly inside the processing chamber R. A plurality of small
holes 56a are formed on the defusing member 56. In such manner, the
air spreads out as far as the edge of the wafer W.
[0055] Furthermore, although not illustrated, similar to each of
the aforesaid embodiments, the vapor is supplied from the supply
port 34b of the holding table 34 in this embodiment.
[0056] According to the present embodiment, first of all, the vapor
is supplied and the vapor uniformly adheres to the front surface of
the resist film coated on the wafer W. Next, the drying process is
performed blowing heating air onto the surface of the wafer W,
causing the moisture adhered on the wafer W to evaporate so that
the moisture remains on the surface of the wafer W.
[0057] With such processing method, similar to each of the
aforesaid embodiments, the amount of exposure reaching the resist
can be increased as much as possible while keeping the amount of
exposure in the exposing step constant.
[0058] The present invention is not limited to an embodiment as
described above, however, various kinds of modification is
possible.
[0059] For example, as shown in FIG. 10, the wafer W can be spun in
.theta.-direction while being held with a spin chuck 63 which
rotatably holds the wafer W and ultra-pure water is supplied onto
the surface of wafer W with a stick-shaped supply nozzle 69 having
a slit shaped discharge opening (not shown) and the moisture may be
adhered uniformly on the wafer W coated with the resist. In
addition, in this case, the vapor may be gushed out from the supply
nozzle 6c while rotating the wafer W.
[0060] The holding table 34 as shown in FIGS. 7 and 8, may be
replaced with, for example, a cooling plate having a cooling means
such as cooling water or Peltier element. With this embodiment, a
cooling process by the cooling plate can be performed after the
heating process performed with the transferring body 52 as shown in
FIG. 8. Throughput can be improved compared to a case, for example,
where the wafer is transferred to another cooling unit for the
cooling process to be performed.
[0061] Furthermore, a semi-conductor wafer is used as a substrate
in each of the embodiments described above, however, the present
invention can also be applied to a substrate such as a glass
substrate used for a liquid crystal display and the like.
[0062] FIG. 11 is a sectional view showing a vapor processing unit
according to the fifth embodiment of the present invention.
Incidentally in FIG. 11, the same numerals and symbols will be used
to designate the same components as those in FIG. 4, and the
explanation thereof will be omitted.
[0063] A vapor processing unit 70 has an increasing and reducing
pressure apparatus 72. A pipe 75 is connected between the
increasing and reducing pressure apparatus 72 and an air
introduction and exit port 73 provided on the lid 32 and the
increasing and reducing pressure apparatus 72 controls the pressure
inside the processing chamber R under control of a controller 71.
As the increasing and reducing pressure apparatus 72, a vacuum pump
and the like which introduces air into and sucks out the air out of
the processing chamber R can be used.
[0064] A pressure measuring sensor 74 is attached, for example, to
the inside of the lid 32. The pressure measuring sensor 74 detects
the pressure inside the processing chamber R and the controller 71
controls the increasing and reducing pressure apparatus 72
corresponding to the detected results of the pressure measuring
sensor 74.
[0065] In the vapor processing unit 70 structured as above, the
pressure inside the processing chamber R is controlled, therefore,
the amount of water adhered to the wafer W as a result of the vapor
processing can be adjusted. Thus, dryness of the wafer can freely
be controlled.
[0066] One example of an operation of the vapor processing unit 70
structured in such manner will be described fully. First, after the
wafer W is placed on the holding table 34 and the lid 32 is lowered
and become hermetically sealed, the vapor is supplied into the
processing chamber R with the vapor generator 35. Then, the
increasing and reducing pressure apparatus 72 is activated, for
example, while the vapor flowing into the processing chamber R or
after the inflow of the vapor is stopped, so that the pressure
inside the processing chamber R becomes bigger, for example, than
the atmospheric pressure. In such manner, the vapor evaporated from
the substrate can be restrained for a predetermined time period
starting from the exposure of the substrate to the vapor, and the
effect of adhering the vapor uniformly on the substrate is
encouraged. The predetermined time period may be, for example,
several seconds to several minutes, the same can be applied to the
examples hereafter.
[0067] On the other hand, after the predetermined time period is
passed, the pressure inside the processing chamber R is adjusted to
be smaller than the atmospheric pressure. As a result, after the
predetermined time period is passed, the moisture adhered on the
surface of the wafer W is actively vaporized and the drying process
can be performed uniformly, for example, up to a point where the
predetermined amount of moisture remains on the surface of the
wafer W. In other words, drying process under reduced pressure may
be performed. With this method, the amount of exposure reaching the
resist can be increased as much as possible, while keeping the
uniformity in the amount of exposure in the exposing step
constant.
[0068] FIG. 12 is a sectional view showing a vapor processing unit
according to the sixth embodiment of the present invention.
Incidentally, in FIG. 12, the same numerals and symbols will be
used to designate the same components as those in FIG. 4, and the
explanation thereof will be omitted.
[0069] In a vapor processing unit 80, a moisture film thickness
measuring apparatus 81 is attached inside the lid 32. The moisture
film thickness measuring apparatus 81 measures the film thickness
of the vapor adhered to the surface of the wafer W, after the wafer
W is exposed to the vapor. As the moisture film thickness measuring
apparatus 81, for example, an apparatus using a principle of
measuring the film thickness with light interference can be
used.
[0070] A controller 82 controls switching of the pump 28
corresponding to the measurement result of the moisture film
thickness measuring apparatus 81, therefore, the amount of vapor
supplied into the processing chamber R can be controlled.
[0071] One example of an operation of the vapor processing unit 80
structured in such manner will be described concretely. First,
after the wafer W is placed on the holding table 34, the lid 32 is
lowered to become hermetically sealed, the vapor is supplied into
the processing chamber R with the vapor generator 35. Then, for
example, while the vapor is flowing into the processing chamber R,
the moisture film thickness measuring apparatus 81 measures the
film thickness of the moisture adhered on the surface of the wafer
W. A controller 82 controls switching of the pump 28 corresponding
to the measurement result, therefore, the amount of vapor supplied
into the processing chamber R is controlled. One example of an
operation of the vapor processing unit 70 structured in such manner
will be described concretely. First, after the wafer W is placed on
the holding table 34, the lid 32 is lowered to become hermetically
sealed, the vapor is supplied into the processing chamber R with
the vapor generator 35. Then, for example, while the vapor is
flowing into the processing chamber R, the moisture film thickness
measuring apparatus 81 measures the film thickness of the moisture
adhered on the surface of the wafer W. After that, for example when
the moisture film thickness reaches to a predetermined value, the
supply of the vapor is stopped. With this configuration, an
appropriate amount of vapor can uniformly be adhered onto the
surface of the wafer W. As a result, a minimum amount of moisture
can be adhered onto the wafer W by supplying minimum amount of
vapor, therefore, excessive supply of vapor can be prevented. In
the same time, the drying process described in the above mentioned
second and third embodiments and the like can be omitted, which
causes the processing time to be shortened.
[0072] Incidentally, according to the sixth embodiment, the
measurement of the moisture film thickness measuring apparatus 81
may not be included in the above-mentioned processing unit 80, but
may be included in a separate measuring unit. In that case, the
vapor processed wafer may be transferred to the separate measuring
unit after the completion of the vapor process in the vapor
processing unit, and the measurement with the moisture film
thickness measuring apparatus 81 may be performed.
[0073] Moreover, instead of using the moisture film thickness
measuring apparatus 81, for example, wetting condition on the
surface of the wafer W may be picked up as an image using an image
pick-up apparatus like a CCD camera.
[0074] As described above, according to the present invention, by
placing a substrate coated with resist in vapor, moisture adheres
uniformly on the resist of the substrate, therefore, the uniform
exposure can be realized in an exposing step, and uniformity of the
line width and the like can be improved.
[0075] The disclosure of Japanese Patent Application No.2001-358183
filed Nov. 22, 2001 including specification, drawings and claims
are herein incorporated by reference in its entirety.
[0076] Although the present invention has been shown and described
with respect to a best mode embodiment thereof, it should be
understood by those skilled in the art that the foregoing and
various other changes, omissions, and additions in the form and
detail thereof may be made therein without departing from the
spirit and scope of the present invention.
* * * * *