U.S. patent application number 16/238236 was filed with the patent office on 2019-07-04 for substrate processing apparatus and substrate processing method.
The applicant listed for this patent is TOKYO ELECTRON LIMITED. Invention is credited to Satoshi BIWA, Yuichi DOUKI, Masataka GOSHO, Yuichiro KUNUGIMOTO, Satoshi OKAMURA, Katsuhiro OOKAWA.
Application Number | 20190206702 16/238236 |
Document ID | / |
Family ID | 67059935 |
Filed Date | 2019-07-04 |
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United States Patent
Application |
20190206702 |
Kind Code |
A1 |
GOSHO; Masataka ; et
al. |
July 4, 2019 |
SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD
Abstract
There is provided a substrate processing apparatus comprising a
liquid amount detecting part configured to detect a liquid amount
of a liquid film formed on a substrate; and a coating state
detecting part configured to detect a coating state of the
substrate with the liquid film formed thereon.
Inventors: |
GOSHO; Masataka; (Koshi
City, JP) ; DOUKI; Yuichi; (Koshi City, JP) ;
BIWA; Satoshi; (Koshi City, JP) ; OKAMURA;
Satoshi; (Koshi City, JP) ; OOKAWA; Katsuhiro;
(Koshi City, JP) ; KUNUGIMOTO; Yuichiro; (Koshi
City, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOKYO ELECTRON LIMITED |
Tokyo |
|
JP |
|
|
Family ID: |
67059935 |
Appl. No.: |
16/238236 |
Filed: |
January 2, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/67248 20130101;
H01L 21/02101 20130101; B08B 3/08 20130101; B08B 7/04 20130101;
H01L 21/02057 20130101; H01L 21/68764 20130101; H01L 21/67253
20130101; H01L 21/67028 20130101; H01L 21/67051 20130101; H01L
22/12 20130101; H01L 21/67288 20130101; H01L 22/20 20130101 |
International
Class: |
H01L 21/67 20060101
H01L021/67; H01L 21/687 20060101 H01L021/687; H01L 21/66 20060101
H01L021/66; H01L 21/02 20060101 H01L021/02; B08B 3/08 20060101
B08B003/08; B08B 7/04 20060101 B08B007/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 4, 2018 |
JP |
2018000247 |
Oct 26, 2018 |
JP |
2018201615 |
Claims
1. A substrate processing apparatus comprising: a liquid amount
detecting part configured to detect a liquid amount of a liquid
film formed on a substrate; and a coating state detecting part
configured to detect a coating state of the substrate with the
liquid film formed thereon.
2. The substrate processing apparatus of claim 1, further
comprising: a drying part configured to perform a drying process on
the substrate on which the liquid film is formed.
3. The substrate processing apparatus of claim 2, wherein the
liquid amount detecting part is configured to detect the liquid
amount before the substrate is transferred to the drying part.
4. The substrate processing apparatus of claim 2, wherein the
liquid amount detecting part is configured to detect the liquid
amount after the substrate is transferred to the drying part.
5. The substrate processing apparatus of claim 2, wherein the
coating state detecting part is configured to detect the coating
state before the substrate is transferred to the drying part.
6. The substrate processing apparatus of claim 1, wherein the
coating state detecting part is configured to detect the coating
state using an imaging device.
7. The substrate processing apparatus of claim 6, further
comprising: a laser irradiation part configured to irradiate a
laser beam to the substrate on which the liquid film is formed; and
a screen configured to have a reflected beam, which is generated
when the laser beam is reflected at the substrate, projected onto
the screen, wherein the imaging device is configured to pick up the
reflected beam projected onto the screen, and the coating state
detecting part is configured to detect the coating state based on
an image data obtained by the imaging device.
8. The substrate processing apparatus of claim 6, further
comprising: an irradiation part configured to irradiate a
monochromatic beam to the substrate on which the liquid film is
formed, wherein the imaging device is configured to pick up an
image of the substrate to which the monochromatic beam is
irradiated, and the coating state detecting part is configured to
detect the coating state based on an image data obtained by the
imaging device.
9. The substrate processing apparatus of claim 1, wherein the
coating state detecting part is configured to detect the coating
state using an infrared sensor.
10. A substrate processing method, comprising: detecting a coating
state of a substrate with a liquid film formed thereon; detecting a
liquid amount of the liquid film when the coating state is a
predetermined state in which the liquid film covers a pattern of
the substrate; and performing a drying process on the substrate
when the liquid amount falls within a preset range.
11. The substrate processing method of claim 10, further
comprising: regulating a supply amount of a liquid that forms the
liquid film when the coating state is not the predetermined state
or when the liquid amount is outside of the preset range.
12. A substrate processing method, comprising: detecting a first
weight of a substrate having a surface on which a liquid film is
formed before a drying process; detecting a coating state of the
substrate with the liquid film formed thereon before the drying
process; performing the drying process on the substrate on which
the liquid film has been formed; detecting a second weight of the
substrate after the drying process; and detecting a state of the
surface of the substrate after the drying process.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application Nos. 2018-000247 and
2018-201615, filed on Jan. 4, 2018 and Oct. 26, 2018, respectively,
the entire contents of which are incorporated herein by
reference.
TECHNICAL FIELD
[0002] Embodiments of the present disclosure relate to a substrate
processing apparatus and a substrate processing method.
BACKGROUND
[0003] In the related art, there has been known a substrate
processing apparatus which forms a dry-preventing liquid film on a
front surface of a substrate, and performs a drying process by
bringing the substrate having the liquid film formed thereon into
contact with a supercritical fluid.
SUMMARY
[0004] However, in the conventional substrate processing apparatus,
the drying process is sometimes performed in a state where a liquid
film is improperly formed on the substrate. This results in a poor
yield of the substrate after the drying process.
[0005] Some embodiments of the present disclosure provide a
substrate processing apparatus and a substrate processing method
that improve the yield of a substrate.
[0006] According to one embodiment of the present disclosure, there
is provided a substrate processing apparatus including: a liquid
amount detecting part configured to detect a liquid amount of a
liquid film formed on a substrate; and a coating state detecting
part configured to detect a coating state of the substrate with the
liquid film formed thereon.
[0007] According to another embodiment of the present disclosure,
there is provided a substrate processing method, including:
detecting a coating state of a substrate with a liquid film formed
thereon; detecting a liquid amount of the liquid film when the
coating state is a predetermined state in which the liquid film
covers a pattern of the substrate; and performing a drying process
on the substrate when the liquid amount falls within a
predetermined range.
[0008] According to another embodiment of the present disclosure,
there is provided a substrate processing method, including:
detecting a first weight of a substrate having a front surface on
which a liquid film is formed before a drying process; detecting a
coating state of the substrate with the liquid film formed thereon
before the drying process; performing the drying process on the
substrate on which the liquid film has been formed; detecting a
second weight of the substrate after the drying process; and
detecting a state of the front surface of the substrate after the
drying process.
BRIEF DESCRIPTION OF DRAWINGS
[0009] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate embodiments of
the present disclosure, and together with the general description
given above and the detailed description of the embodiments given
below, serve to explain the principles of the present
disclosure.
[0010] FIG. 1 is a schematic view showing a schematic configuration
of a substrate processing system according to a first
embodiment.
[0011] FIG. 2 is a cross-sectional view showing a schematic
configuration of a delivering part.
[0012] FIG. 3 is a cross-sectional view showing a schematic
configuration of a cleaning process unit.
[0013] FIG. 4 is an external perspective view showing a
configuration of a drying process unit.
[0014] FIG. 5A is a schematic cross-sectional view showing a
portion of the drying process unit at a delivery position.
[0015] FIG. 5B is a schematic cross-sectional view showing a
portion of the drying process unit at a standby position.
[0016] FIG. 6 is a schematic block diagram of a control device
according to the first embodiment.
[0017] FIG. 7A is a schematic view showing a state in which no
defective portion is generated in a liquid film formed of an IPA
liquid.
[0018] FIG. 7B is a schematic view showing a state in which a
defective portion is generated in a liquid film formed of an IPA
liquid.
[0019] FIG. 8 is a flowchart illustrating a substrate process in
the first embodiment.
[0020] FIG. 9 is a schematic view showing a configuration of a
substrate processing system according to a second embodiment.
[0021] FIG. 10A is a schematic cross-sectional view showing a
portion of a drying process unit according to the second
embodiment.
[0022] FIG. 10B is a schematic cross-sectional view of the drying
process unit, which represents a state in which a wafer W is
mounted on a holding plate.
[0023] FIG. 11 is a schematic block diagram of a control device
according to the second embodiment.
[0024] FIG. 12 is a flowchart illustrating a substrate process
according to the second embodiment.
[0025] FIG. 13 is a schematic plan view of a drying process unit
according to a third embodiment.
[0026] FIG. 14 is a schematic cross-sectional view showing a
portion of the drying process unit taken along line XIV-XIV of FIG.
13.
[0027] FIG. 15 is a schematic view showing reflection of laser
beams from a wafer on which a liquid film formed of an IPA liquid
is formed.
[0028] FIG. 16A is a schematic view showing reflected beams in a
state where no defective portion is generated in a liquid film
formed of an IPA liquid.
[0029] FIG. 16B is a schematic view showing reflected beams in a
state where a defective portion is generated in a liquid film
formed of an IPA liquid.
[0030] FIG. 17 is a schematic block diagram of a control device
according to the third embodiment.
[0031] FIG. 18 is a schematic plan view of a drying process unit
according to a fourth embodiment.
[0032] FIG. 19 is a schematic cross-sectional view showing a
portion of the drying process unit taken along line XIX-XIX of FIG.
18.
[0033] FIG. 20 is a view illustrating the generation principle of
an interference pattern.
[0034] FIG. 21A is a schematic view of a wafer in which no
defective portion is generated in a liquid film formed of an IPA
liquid when obliquely viewed from the top.
[0035] FIG. 21B is a schematic view of a wafer in which no
defective portion is generated in a liquid film formed of an IPA
liquid when obliquely viewed from the top.
[0036] FIG. 22 is a schematic plan view of a drying process unit of
a substrate processing system according to a modified example.
DETAILED DESCRIPTION
[0037] Hereinafter, embodiments of a substrate processing apparatus
and a substrate processing method of the present disclosure will be
described in detail with reference to the accompanying figures.
Further, the present disclosure is not limited by the embodiments
to be described hereafter. In the following detailed description,
numerous specific details are set forth in order to provide a
thorough understanding of the present disclosure. However, it will
be apparent to one of ordinary skill in the art that the present
disclosure may be practiced without these specific details. In
other instances, well-known methods, procedures, systems, and
components have not been described in detail so as not to
unnecessarily obscure aspects of the various embodiments.
[0038] For the clarification of a positional relationship, there is
shown a rectangular coordinate system in which an X-axis direction,
a Y-axis direction and a Z-axis direction, which are orthogonal to
one another, are defined in the following description and a
positive Z-axis direction is defined as a vertical upward
direction.
First Embodiment
<Outline of Substrate Processing System>
[0039] A substrate processing system 1 according to a first
embodiment will be described with reference to FIG. 1. FIG. 1 is a
schematic view showing a schematic configuration of the substrate
processing system 1 according to the first embodiment.
[0040] The substrate processing system 1 includes a
loading/unloading station 2 and a processing station 3. The
loading/unloading station 2 and the processing station 3 are
installed adjacent to each other. The substrate processing system 1
corresponds to a substrate processing apparatus.
[0041] The loading/unloading station 2 includes a carrier mounting
part 11 and a transfer part 12. A plurality of carriers C, each of
which receives a plurality of semiconductor wafers W (hereafter,
referred to as wafers W) in a horizontal posture, is mounted on the
carrier mounting part 11.
[0042] The transfer part 12 is disposed adjacent to the carrier
mounting part 11 and includes a substrate transfer device 13 and a
delivering part 14 installed therein. The substrate transfer device
13 includes a wafer holding mechanism that holds a wafer W. The
substrate transfer device 13 can move in horizontal and vertical
directions and can swivel about a vertical axis, so that the
substrate transfer device 13 transfers the wafer W between the
carrier C and the delivering part 14 using the wafer holding
mechanism. An exemplary configuration of the delivering part 14
will be described below.
[0043] The processing station 3 is installed adjacent to the
transfer part 12. The processing station 3 includes a transfer part
15, a plurality of cleaning process units 16, and a plurality of
drying process units 17. The plurality of cleaning process units 16
and the plurality of drying process units 17 are installed in
parallel at both sides of the transfer part 15. The arrangements
and numbers of the cleaning process units 16 and the drying process
units 17 shown in FIG. 1 are examples and are not limited to those
shown in the figure.
[0044] The transfer part 15 includes a substrate transfer device 18
installed therein. The substrate transfer device 18 includes a
wafer holding mechanism that holds the wafer W. The substrate
transfer device 18 can move in horizontal and vertical directions
and can swivel about a vertical axis, so that the substrate
transfer device 18 transfers the wafer W between the delivering
part 14, the cleaning process units 16 and the drying process units
17 using the wafer holding mechanism.
[0045] The cleaning process unit 16 performs a predetermined
cleaning process on the wafer W which is transferred by the
substrate transfer device 18. An exemplary configuration of the
cleaning process unit 16 will be described below.
[0046] The drying process unit 17 performs a predetermined drying
process on the wafer W which has been cleaned by the cleaning
process unit 16. An exemplary configuration of the drying process
unit 17 will be described below.
[0047] Further, the substrate processing system 1 includes a
control device 4. An exemplary configuration of the control device
4 will be described below.
[0048] In the substrate processing system 1 configured as above,
first, the substrate transfer device 13 of the loading/unloading
station 2 takes out a wafer W from the carrier C mounted on the
carrier mounting part 11 and mounts the same on the delivering part
14. The wafer W mounted on the delivering part 14 is picked up by
the substrate transfer device 18 of the processing station 3 and is
loaded into to the cleaning process unit 16.
[0049] The wafer W loaded into the cleaning process unit 16 is
subjected to the cleaning process by the cleaning process unit 16.
Subsequently, the wafer W is unloaded from the cleaning process
unit 16 by the substrate transfer device 18. The wafer W unloaded
from the cleaning process unit 16 is loaded into the drying process
unit 17 by the substrate transfer device 18. The wafer W is
subjected to the drying process by the drying process unit 17.
[0050] The wafer W which has been subjected to the drying process
by the drying process unit 17 is unloaded from the drying process
unit 17 by the substrate transfer device 18 and is then mounted on
the delivering part 14. The processed wafer W mounted on the
delivering part 14 is returned to the carrier C of the carrier
mounting part 11 by the substrate transfer device 13.
<Outline of Delivering Part>
[0051] Next, the delivering part 14 will be described with
reference to FIG. 2. FIG. 2 is a cross-sectional view showing a
schematic configuration of the delivering part 14.
[0052] The delivering part 14 includes a case 40, a base 41, a
plurality of lifting members 42, and a load cell 43. Openings 40A
and 40B through which the wafer W is transferred by the substrate
transfer devices 13 and 18 are formed in the case 40. The base 41
is disposed inside the case 40. Insertion holes into which the
respective lifting members 42 are inserted are formed in the base
41.
[0053] The lifting members 42 are supported by the base 41 so that
they can be moved up and down by a lifting drive part (not shown).
When the wafer W held by the substrate transfer device 13 and the
substrate transfer device 18 is mounted on tip ends of the lifting
members 42, the lifting members 42 support a rear surface of the
wafer W. When the lifting members 42 are moved down from a
predetermined delivery position by the lifting drive part while
supporting the wafer W, the wafer W is mounted on the load cell 43.
Subsequently, in the state where the wafer W is mounted on the load
cell 43, when the lifting members 42 are moved up by the lifting
drive part, the lifting members 42 are brought into contact with
the rear surface of the wafer W to support the wafer W. Thus, the
wafer W is moved up to the delivery position.
[0054] The load cell 43 measures the weight of the wafer W mounted
thereon from the carrier C or the wafer W which has been subjected
to the drying process by the drying process unit 17, and outputs a
signal corresponding to the weight of the wafer W to the control
device 4.
<Outline of Cleaning Process Unit>
[0055] Next, the cleaning process unit 16 will be described with
reference to FIG. 3. FIG. 3 is a cross-sectional view showing a
schematic configuration of the cleaning process unit 16. The
cleaning process unit 16 is, for example, a single-wafer cleaning
process unit configured to clean the plurality of wafers W one by
one through spin cleaning.
[0056] The cleaning process unit 16 includes a wafer holding
mechanism 25, a nozzle arm 26, and an infrared sensor 27.
[0057] The wafer holding mechanism 25 includes a lifter 28 and a
wafer holding part 29. The wafer holding mechanism 25 is disposed
inside an outer chamber 23 which provides a processing space. The
wafer holding mechanism 25 rotates about a vertical axis while
holding the wafer W in a substantially horizontal posture by the
wafer holding part 29, thereby rotating the wafer W.
[0058] The lifter 28 includes a plurality of lifter pins 28a, a
supporting part 28b which is connected to lower ends of the lifter
pins 28a to support the lifter pins 28a, and a load cell 28c
disposed on a lower surface of the supporting part 28b.
[0059] The lifter pins 28a are expanded or contracted in an up-down
direction by an expansion/contraction drive part (not shown). The
lifter pins 28a deliver the wafer W with respect to the substrate
transfer device 18 at an upper delivery position. Further, the
lifter pins 28a deliver the wafer W with respect to the wafer
holding part 29 at a lower delivery position. The lifter pins 28a
is brought into contact with the rear surface of the wafer W to
support the wafer W. When the lifter pins 28a are further
contracted while holding the wafer W by the wafer holding part 29,
they are separated from the rear surface of the wafer W.
[0060] The load cell 28c measures the weight of the wafer W
supported by the lifter pins 28a. The load cell 28c measures the
weight of the wafer W before the cleaning process is performed on
the wafer W and the weight of the wafer W after the cleaning
process is performed on the wafer W. The load cell 28c outputs
signals corresponding to the weights of the wafer W to the control
device 4.
[0061] In some embodiments, the lifter pins 28a may be
non-extendible rod-shaped members. In this case, the lifter pins
28a, the supporting part 28b and the load cell 28c of the lifter 28
are formed as a unit and are moved up and down.
[0062] The wafer holding part 29 holds the wafer W in a
substantially horizontal posture. The wafer holding mechanism 25
rotates the wafer W by rotating about a vertical axis while holding
the wafer W with the wafer holding part 29.
[0063] The infrared sensor 27 measures a temperature of the wafer W
which has been subjected to the cleaning process, and outputs a
signal corresponding to the measured temperature of the wafer W to
the control device 4. The infrared sensor 27 measures the
temperature of the wafer W in the state where the wafer W is held
by the wafer holding part 29. Further, the infrared sensor 27 may
measure the temperature of the wafer W in the state where the wafer
W is supported by the lifter pins 28a.
[0064] In some embodiments, the infrared sensor 27 may be installed
at plural locations. For example, in a case where one infrared
sensor 27 is not able to detect the temperature of the entire area
of the wafer W, the temperature of the entire area of the wafer W
can be detected by the plurality of infrared sensors 27.
[0065] The nozzle arm 26 advances above the wafer W under rotation,
and supplies a chemical solution, a rinse solution, an acid
chemical solution, and IPA in a predetermined order from a chemical
solution nozzle 26a installed at a tip end of the nozzle arm 26,
thus performing the cleaning process on a front surface of the
wafer W. The nozzle arm 26 may be installed at plural locations.
Further, in the case where the infrared sensor 27 measures the
temperature of the wafer W, the nozzle arm 26 moves backward so as
not to interfere with the measurement by the infrared sensor
27.
[0066] Further, the cleaning process unit 16 includes a chemical
solution supply channel 25a formed inside the wafer holding
mechanism 25. The rear surface of the wafer W is cleaned by the
chemical solution or the rinse solution supplied through the
chemical solution supply channel 25a.
[0067] For example, the cleaning process performed on the wafer W
includes initially removing particles or organic contaminants by an
SCI solution (a mixed solution of ammonia and hydrogen peroxide) as
an alkaline chemical solution, followed by rinse-cleaning with a
deionized water (hereafter, referred to as DIW) as a rinse
solution, followed by removing a natural oxide film by a diluted
hydrofluoric acid solution (hereafter, referred to as DHF) as an
acid chemical solution, followed by rinse-cleaning with DIW.
[0068] Various chemical solutions described above are received in
the outer chamber 23 or an inner cup 24 disposed inside the outer
chamber 23, and are discharged from a liquid drain port 23a formed
in the bottom of the outer chamber 23 or a liquid drain port 24a
formed in the bottom of the inner cup 24. Further, an internal
atmosphere of the outer chamber 23 is exhausted from an exhaust
port 23b formed in the bottom of the outer chamber 23.
[0069] After the above rinsing process is performed on the wafer W,
IPA staying in a liquid state (hereafter, referred to as "IPA
liquid") is supplied to the surface and rear surfaces of the wafer
W while the wafer holding mechanism 25 rotates. Thus, the DIW
remaining on both the front and rear surfaces of the wafer W is
replaced with the IPA liquid. Thereafter, the rotation of the wafer
holding mechanism 25 is slowly stopped. As a result, the IPA liquid
collects on the front surface of the wafer W so that a liquid film
L is formed by the IPA liquid (see FIGS. 7A and 7B). The liquid
film L is formed to cover the entire pattern of the wafer W.
[0070] The wafer W which has been subjected to the cleaning process
in this way is transferred onto the substrate transfer device 18 by
the lifter 28 in the state where the liquid film L made of the IPA
liquid is formed on the front surface of the wafer W, and is
unloaded from the cleaning process unit 16.
[0071] The IPA liquid collecting on the front surface of the wafer
W functions as an anti-drying liquid that prevents the pattern from
collapsing due to evaporation (vaporization) of liquid existing on
the front surface of the wafer W in the course of transferring the
wafer W from the cleaning process unit 16 to the drying process
unit 17 or in the course of loading the wafer W into the drying
process unit 17.
[0072] The wafer W which has been subjected to the cleaning process
in the cleaning process unit 16 and on which the liquid film L of
the IPA liquid is formed, is transferred to the drying process unit
17. In the drying process unit 17, a processing fluid of CO.sub.2
staying in a supercritical state (hereafter, referred to as a
"supercritical fluid") is brought into contact with the IPA liquid
on the front surface of the wafer W. Thus, the IPA liquid is
removed by being dissolved in the supercritical fluid. In this
state, a process of drying the wafer W is performed.
<Outline of Drying Process Unit>
[0073] Next, the configuration of the drying process unit 17 will
be described with reference to FIG. 4. FIG. 4 is an external
perspective view showing the configuration of the drying process
unit 17.
[0074] The drying process unit 17 includes a housing-shaped main
body 31, a holding plate 32, a cover member 33, and a lifter 39. An
opening 34 through which the wafer W is transferred is formed in
the main body 31. The holding plate 32 horizontally holds the wafer
W to be processed. The cover member 33 supports the holding plate
32, and closes the opening 34 when the wafer W is loaded into the
main body 31.
[0075] The main body 31 is a container having a processing space
where the wafer W can be received, and has supply ports 35A and 35B
and a discharge port 36 formed in a wall portion thereof. The
supply port 35A is connected to a supply line 35C for supplying the
supercritical fluid into the processing space. The supply port 35B
is connected to a supply line 35D for supplying the supercritical
fluid into the processing space. The discharge port 36 is connected
to a discharge line 36A for discharging the supercritical fluid
from the processing space.
[0076] The supply port 35A is connected to a side opposite to the
opening 34 in the housing-shaped main body 31. Further, the supply
port 35B is connected to the bottom of the main body 31. Further,
the discharge port 36 is connected to a portion under the opening
34. Although the two supply ports 35A and 35B and the single
discharge port 36 are shown in FIG. 4, the numbers of the supply
ports 35A and 35B and the discharge port 36 are not particularly
limited.
[0077] Fluid supply headers 37A and 37B and a fluid discharge
header 38 are disposed inside the main body 31. A plurality of
holes is formed in each of the fluid supply headers 37A and 37B and
the fluid discharge header 38.
[0078] The fluid supply header 37A is connected to the supply port
35A and is installed adjacent to a side opposite to the opening 34
in the housing-shaped main body 31. Further, the plurality of holes
formed in the fluid supply header 37A face the opening 34.
[0079] The fluid supply header 37B is connected to the supply port
35B and is installed at the center portion of the bottom of the
housing-shaped main body 31. Further, the plurality of holes formed
in the fluid supply header 37B is arranged to be oriented
upward.
[0080] The fluid discharge header 38 is connected to the discharge
port 36 and is installed adjacent to a side close to the opening 34
and under the opening 34 inside the housing-shaped main body 31.
Further, the plurality of holes formed in the fluid discharge
header 38 face the fluid supply header 37A.
[0081] The fluid supply headers 37A and 37B supply the
supercritical fluid into the main body 31. The fluid discharge
header 38 introduces and discharges the supercritical fluid
received in the main body 31 outward of the main body 31. Further,
the IPA liquid dissolved in the supercritical fluid on the front
surface of the wafer W is included in the supercritical fluid that
is discharged outward of the main body 31 through the fluid
discharge header 38.
[0082] The lifter 39 includes a plurality of lifter pins 39a and a
supporting part 39b connected with lower ends of the lifter pins
39a to support a delivery member. The lifter 39 is moved up and
down by a lifting drive part (not shown).
[0083] The lifter 39 is moved up and down between a delivery
position where the wafer W is delivered between the lifter 39 and
the substrate transfer device 18, and a standby position. The
standby position is a lower position where the cover member 33 can
be opened and closed.
[0084] The lifter 39 receives the wafer W from the substrate
transfer device 18 at the delivery position shown in FIG. 5A. The
lifter 39 supports the rear surface of the wafer W using the lifter
pins 39a. The lifter 39 is moved down to the standby position shown
in FIG. 5B while supporting the wafer W by the lifter pins 39a,
thus mounting the wafer W on the holding plate 32. FIG. 5A is a
schematic cross-sectional view showing a portion of the drying
process unit 17 at the delivery position. FIG. 5B is a schematic
cross-sectional view showing a portion of the drying process unit
17 at the standby position.
[0085] Further, after the drying process is finished, the lifter 39
is moved up from the standby position shown in FIG. 5B to support
the rear surface of the wafer W with the lifter pins 39a and
receive the wafer W from the holding plate 32. The lifter 39 is
moved up to the delivery position shown in FIG. 5A while supporting
the rear surface of the wafer W by the lifter pins 39a and deliver
the wafer W to the substrate transfer device 18. The lifter pins
39a are arranged to be inserted into an insertion hole 32a of the
holding plate 32.
[0086] The drying process unit 17 further includes a pressing
mechanism (not shown). The pressing mechanism has a function of
sealing the processing space by pressing the cover member 33 toward
the main body 31 against an internal pressure caused by the
supercritical fluid staying in a supercritical state, which is
supplied into the processing space of the main body 31. In some
embodiments, an insulator or a tape heater may be installed on the
surface of the main body 31 to keep the supercritical fluid
supplied into the processing space at a predetermined
temperature.
[0087] The wafer W which has been subjected to the drying process
in the drying process unit 17 is transferred to the delivering part
14 by the substrate transfer device 18.
<Configuration of Control Device>
[0088] Next, the configuration of the control device 4 will be
described with reference to FIG. 6. FIG. 6 is a schematic block
diagram of the control device 4 according to the first
embodiment.
[0089] The control device 4 is, for example, a computer and
includes a control part 19 and a memory part 20.
[0090] The control part 19 includes a microcomputer composed of a
central processing unit (CPU), a read only memory (ROM), a random
access memory (RAM), an input/output port and the like, and various
circuits. The CPU of such a microcomputer controls the transfer
part 12 (see FIG. 1), the transfer part 15 (see FIG. 1), the
cleaning process unit 16, and the drying process unit 17 and the
like by reading out and executing programs stored in the ROM.
[0091] Further, the programs are recorded in a computer-readable
recording medium and may be installed on the memory part 20 of the
control device 4 from the recording medium. An example of the
computer-readable recording medium may include a hard disk (HD), a
flexible disk (FD), a compact disc (CD), a magnet-optical disk
(MO), a memory card or the like.
[0092] The memory part 20 is implemented, for example, by a
semiconductor memory device such as a RAM, a flash memory or the
like, or a storage device such as a hard disk, an optical disc or
the like. The memory part 20 stores the weights of the wafer W
measured by the load cells 28c and 43.
[0093] The control part 19 includes a liquid amount detecting part
19A, a coating state detecting part 19B, a determining part 19C, a
signal generating part 19D, and an outputting part 19E. Signals
corresponding to the weights of the wafer W which are measured by
the load cells 28c and 43 are inputted to the control part 19. A
signal corresponding to the temperature of the wafer W which is
detected by the infrared sensor 27 is inputted to the control part
19. Further, the control part 19 outputs signals for controlling
the cleaning process unit 16, the drying control unit 17 and the
like.
[0094] The liquid amount detecting part 19A detects a liquid amount
of the liquid film L made of the IPA liquid (hereafter, referred to
as a "liquid amount of the liquid film L"), which is formed on the
wafer W by the cleaning process. Specifically, the liquid amount
detecting part 19A calculates a difference between a weight of the
wafer W after the cleaning process and a weight of the wafer W
before the cleaning process, which are measured by the load cell
28c, and detects the liquid amount of the liquid film L formed on
the wafer W on the basis of the calculated difference.
[0095] Further, the liquid amount detecting part 19A detects a
dried state of the wafer W after the drying process. Specifically,
the liquid amount detecting part 19A calculates a difference
between a weight of the wafer W after the drying process, which is
measured by the load cell 43 and a weight of the wafer W before the
cleaning process, which is measured by the load cell 28c, and
detects the dried state of the wafer W on the basis of the
calculated difference.
[0096] The coating state detecting part 19B detects a coating state
of the wafer W on which the liquid film L of an IPA liquid is
formed. Specifically, the coating state detecting part 19B detects
a temperature distribution based on the temperature of the wafer W
measured by the infrared sensor 27. Subsequently, the coating state
detecting part 19B detects the coating state on the basis of the
detected temperature distribution.
[0097] In the case of detecting the temperature of the wafer W on
which the liquid film L is formed, a temperature of a portion with
the liquid film L is different from that of a portion without the
liquid film L. This is because the wafer W permits infrared rays to
pass through the portion without the liquid film L so that a
temperature of a member under the wafer W, for example, the wafer
holding mechanism 25, is measured.
[0098] For example, in a case where the liquid film L is
appropriately formed on the wafer W, a temperature of the liquid
film L is measured at a predetermined area of the wafer W, as
hatched in FIG. 7A. FIG. 7A is a schematic view showing a state in
which no defective portion Wa (see FIG. 7B) is generated in the
liquid film L of the IPA liquid. The predetermined area is an area
including all areas where a pattern is formed.
[0099] As shown in FIG. 7B, in a case where the liquid film L is
not appropriately formed on the wafer W and a defective portion Wa
where the liquid film L is not formed is generated at a
predetermined area, for example, a temperature of the wafer holding
mechanism 25 is measured at the defective portion Wa. FIG. 7B is a
schematic view showing a state in which the defective portion Wa is
generated in the liquid film L of the IPA liquid.
[0100] As described above, the coating state detecting part 19B
detects the coating state of the wafer W on the basis of the
temperature distribution of the wafer W measured by the infrared
sensor 27.
[0101] The determining part 19C determines whether or not the
liquid amount of the liquid film L formed on a wafer W is normal.
Specifically, the determining part 19C determines whether or not
the liquid amount of the liquid film L falls within a first
predetermined range. The first predetermined range is a preset
range in which pattern collapse or particles that cause a defective
wafer do not occur in the wafer W after the drying process. If it
is determined that the liquid amount of the liquid film L falls
within the first predetermined range, the determining part 19C
determines that the liquid amount of the liquid film L is normal.
If it is determined that the liquid amount of the liquid film L
falls outside the first predetermined range, the determining part
19C determines that the liquid amount of the liquid film L is
abnormal.
[0102] Further, the determining part 19C determines whether or not
the dried state of the wafer W is normal. Specifically, the
determining part 19C determines whether or not a difference between
a weight of the wafer W before the drying process and a weight of
the wafer W before the cleaning process falls within a second
predetermined range. The second predetermined range is a preset
range and is a value at which it is possible to determine the wafer
W has been dried. If it is determined that the different falls
within the second predetermined range, the determining part 19C
determines that the wafer W has been dried and the dried state is
normal. If it is determined that the different falls outside the
second predetermined range, the determining part 19C determines
that the wafer W has not been dried and the dried state is
abnormal.
[0103] Further, the determining part 19C determines whether or not
the coating state of the wafer W is normal. Specifically, the
determining part 19C determines whether the defective portion Wa
exists in a predetermined area. If it is determined that there is
no defective portion Wa in the predetermined area, the determining
part 19C determines that the coating state of the wafer W is
normal. If it is determined that the defective portion Wa exists in
the predetermined area, the determining part 19C determines that
the coating state of the wafer W is abnormal.
[0104] The signal generating part 19D generates a signal for
regulating the liquid film L on the wafer W to the cleaning process
unit 16 when the liquid amount of the liquid film L is abnormal or
when the coating state is abnormal. For example, the signal
generating part 19D generates a signal for supplying the IPA liquid
again.
[0105] In some embodiments, the signal generating part 19D may
generate a signal for regulating the supply amount of the IPA
liquid so that the liquid amount of the liquid film L or the
coating state becomes normal in a subsequent cleaning process. For
example, when the liquid amount of the liquid film L is
insufficient, the signal generating part 19D generates a signal for
increasing the liquid amount of the IPA liquid that is to be
supplied to the wafer W so that the liquid amount of the liquid
film L falls within the first predetermined range. Accordingly, it
is possible to make the liquid amount of the liquid film L or the
coating state normal in the subsequent cleaning process, thus
efficiently performing the substrate process.
[0106] When the dried state of the wafer W is abnormal, the signal
generating part 19D generates a signal for returning the wafer W to
the cleaning process unit 16 where the wafer W is subjected to a
sequence of processes starting from the cleaning process again.
Further, the signal generating part 19D may generate a signal for
regulating the drying process so that the dried state of the wafer
W becomes normal in a subsequent drying process. The signal
generating part 19D, for example, generates a signal for
lengthening a time period of the drying process.
[0107] The outputting part 19E outputs the signal generated by the
signal generating part 19D to the cleaning process unit 16 or the
drying process unit 17.
<Substrate Process>
[0108] Next, the substrate process according to the first
embodiment will be described with reference to FIG. 8. FIG. 8 is a
flowchart illustrating the substrate process according to the first
embodiment.
[0109] The substrate processing system 1 performs a first transfer
process (S10). The substrate processing system 1 transfers the
wafer W to the cleaning process unit 16 from the carrier C through
the delivering part 14 using the substrate transfer device 13 and
the substrate transfer device 18. The substrate processing system 1
mounts the wafer W on the lifter pins 28a of the lifter 28.
[0110] The substrate processing system 1 measures the weight of the
wafer W before the cleaning process, namely before the liquid film
L of the IPA liquid is formed on the wafer W, using the load cell
28c.
[0111] The substrate processing system 1 performs the cleaning
process (S12). The substrate processing system 1 measures the
weight of the wafer W before the liquid film L of the IPA liquid is
formed, and then delivers the wafer W to the wafer holding part 29
from the lifter pins 28a. Thus, the wafer W is held by the wafer
holding part 29. The substrate processing system 1 removes
contaminants and performs a rinse-cleaning process. Further, the
substrate processing system 1 supplies the IPA liquid for a
predetermined period of time at a predetermined flow rate to form
the liquid film L of the IPA liquid on the front surface of the
wafer W.
[0112] The substrate processing system 1 detects a coating state
(S13). The substrate processing system 1 measures a temperature of
the wafer W using the infrared sensor 27 and detects the coating
state on the basis of temperature distribution of the wafer W.
[0113] The substrate processing system 1 determines whether or not
the coating state is normal (S14). If it is determined that the
coating state is normal (Yes in S14), the substrate processing
system 1 measures the weight of the wafer W on which the liquid
film L of the IPA liquid is formed, using the load cell 28c (S15).
The substrate processing system 1 delivers the wafer W to the
lifter pins 28a from the wafer holding part 29 such that the wafer
W is supported by the lifter pins 28a, and measures the weight of
the wafer W on which the liquid film L of the IPA liquid is
formed.
[0114] The substrate processing system 1 determines whether or not
the liquid amount of the liquid film L is normal (S16). If it is
determined that the coating state is abnormal (No in S14) or that
the liquid amount of the liquid film L is abnormal (No in S16), the
substrate processing system 1 regulates the liquid film L of the
IPA liquid formed on the wafer W (S17). The substrate processing
system 1 detects the coating state after regulating the liquid film
L of the IPA liquid (S13).
[0115] If it is determined that the liquid amount of the liquid
film L is normal (Yes in S16), the substrate processing system 1
performs a second transfer process (S18). The substrate processing
system 1 transfers the wafer W from the cleaning process unit 16 to
the drying process unit 17 using the substrate transfer device 18
to load the wafer W into the drying process unit 17.
[0116] The substrate processing system 1 performs a drying process
(S19) and subsequently, performs a third transfer process (S20).
The substrate processing system 1 transfers the wafer W from the
drying process unit 17 to the delivering part 14 using the
substrate transfer device 18 to mount the wafer W on the delivering
part 14.
[0117] The substrate processing system 1 measures the weight of the
wafer W after the drying process using the load cell 43 (S21).
[0118] The substrate processing system 1 determines whether or not
the dried state of the wafer W is normal (S22). If it is determined
that the dried state of the wafer W is abnormal (No in S22), the
substrate processing system 1 performs the cleaning process again
(S12). The substrate processing system 1 transfers the wafer W from
the delivering part 14 to the cleaning process unit 16 using the
substrate transfer device 18. In the cleaning process unit 16, the
liquid film L of the IPA liquid is formed on the front surface of
the wafer W.
[0119] If it is determined that the dried state of the wafer W is
normal (Yes in S22), the substrate processing system 1 performs a
fourth transfer process (S23). The substrate processing system 1
transfers the wafer W from the delivering part 14 to the carrier C
using the substrate transfer device 13.
[0120] The substrate processing system 1 detects a liquid amount of
the liquid film L formed on the wafer W using the liquid amount
detecting part 19A, and detects a coating state of the wafer W on
which the liquid film L of the IPA liquid is formed, using the
coating state detecting part 19B. Accordingly, the substrate
processing system 1 can detect whether the liquid film L of the IPA
liquid has been appropriately formed on the wafer W, which improves
the yield of the wafer W after the drying process.
[0121] The substrate processing system 1 measures the weight of the
wafer W before and after the liquid film L of the IPA liquid is
formed, using the same load cell 28c, and detects a liquid amount
of the liquid film L on the basis of the measured weights.
Accordingly, it is possible to suppress influence of a measurement
error by the load cell and to accurately detect the liquid amount
of the liquid film L, as compared with a case where the liquid
amount of the liquid film L is detected using different load
cells.
[0122] The substrate processing system 1 performs the drying
process on the wafer W on which the liquid film L of the IPA liquid
is formed. Specifically, if it is determined that the coating state
of the wafer W is normal and the liquid amount of the liquid film L
is normal, the substrate processing system 1 performs the drying
process. Accordingly, the substrate processing system 1 can
suppress pattern collapse in the wafer W after the drying process
and can prevent generation of particles in the wafer W after the
drying process, which improves the yield of the wafer W.
[0123] The substrate processing system 1 detects the liquid amount
of the liquid film L before the wafer W is transferred to the
drying process unit 17, specifically in the case where the wafer W
is loaded into the cleaning process unit 16. Accordingly, in the
case where the liquid amount of the liquid film L is abnormal, the
substrate processing system 1 can regulate the liquid film L of the
IPA liquid in the cleaning process unit 16. Therefore, the
substrate processing system 1 can regulate the liquid film L of the
IPA liquid without unloading the wafer W from the cleaning process
unit 16, which shortens a period of time required to regulate the
liquid film L.
[0124] The substrate processing system 1 detects the coating state
of the wafer W before the wafer W is transferred to the drying
process unit 17, specifically in the state where the wafer W is
loaded into the cleaning process unit 16. Accordingly, in the case
where the coating state of the wafer W is abnormal, the substrate
processing system 1 can regulate the liquid film L of the IPA
liquid in the cleaning process unit 16. Therefore, the substrate
processing system 1 can regulate the liquid film L of the IPA
liquid without unloading the wafer W from the cleaning process unit
16, which shortens a period of time required to regulate the liquid
film L.
[0125] The substrate processing system 1 detects the coating state
of the wafer W using the infrared sensor 27. Accordingly, in the
case where the defective portion Wa is generated in the liquid film
L of the IPA liquid, it is possible to accurately detect the
generation of the defective portion Wa.
Second Embodiment
<Outline of Substrate Processing System>
[0126] Next, a substrate processing system according to a second
embodiment will be described with reference to FIG. 9. FIG. 9 is a
schematic view showing the schematic configuration of the substrate
processing system according to the second embodiment. Here, the
substrate processing system according to the second embodiment will
be described with a focus on the differences from the substrate
processing system 1 according to the first embodiment, and the
description of the same configuration as the substrate processing
system 1 according to the first embodiment will be omitted.
[0127] The substrate processing system according to the second
embodiment includes a regulating unit 50 configured to regulate a
liquid film L of the IPA liquid. The regulating unit 50 regulates
the liquid film L of the IPA liquid when a liquid amount of the
liquid film L is abnormal or a coating state is abnormal.
[0128] The regulating unit 50 is installed adjacent to the transfer
part 15. The wafer W can be transferred by the substrate transfer
device 18.
[0129] The load cell 43 (see FIG. 2) installed in the delivering
part 14 measures a weight of the wafer W transferred by the carrier
C. That is to say, the load cell 43 measures the weight of the
wafer W before the cleaning process is performed.
[0130] Further, a cleaning process unit 16A of the substrate
processing system according to the second embodiment does not
include the load cell 28c and the infrared sensor 27 of the
cleaning process unit 16 according to the first embodiment.
<Outline of Drying Process Unit>
[0131] As shown in FIG. 10A, a drying process unit 17A according to
the second embodiment further includes a load cell 39c and an
infrared sensor 60. FIG. 10A is a schematic cross-sectional view
showing a portion of the drying process unit 17A according to the
second embodiment.
[0132] The load cell 39c is installed on a lower surface of a
supporting part 39b of a lifter 39A. As shown in FIG. 10A, the load
cell 39c measures a weight of the wafer W in a state where the
wafer W is supported by lifter pins 39a. The load cell 39c measures
a weight of the wafer W on which the liquid film L of the IPA
liquid is formed and a weight of the wafer W after the drying
process.
[0133] The infrared sensor 60 is installed at an upper portion of a
main body 31 through a support arm 61. As shown in FIG. 10B, the
infrared sensor 60 measures a temperature of the wafer W in a state
where the wafer W is mounted on a holding plate 32. FIG. 10B is a
schematic cross-sectional view of the drying process unit 17A,
which shows a state where the wafer W is mounted on the holding
plate 32.
<Outline Control Device>
[0134] As shown in FIG. 11, signals corresponding to the weight of
the wafer W, which are measured by the load cells 39c and 43, are
inputted to a control part 19 of the control device 4. Further, a
signal corresponding to the temperature of the wafer W, which is
detected by the infrared sensor 60, is inputted to the control part
19. FIG. 11 is a schematic block diagram of the control device 4
according to the second embodiment.
[0135] A liquid amount detecting part 19A calculates a difference
between a weight of the wafer W after the cleaning process, which
is measured by the load cell 39c, and a weight of the wafer W
before the cleaning process, which is measured by the load cell 43,
and detects a liquid amount of the liquid film L formed on the
wafer W.
[0136] Further, the liquid amount detecting part 19A calculates a
difference between a weight of the wafer W after the drying
process, which is measured by the load cell 39c, and a weight of
the wafer W before the cleaning process, which is measured by the
load cell 43, and detects a dried state of the wafer W.
[0137] The substrate processing system according to the second
embodiment measures a liquid amount of the liquid film L and a
coating state after the wafer W on which the liquid film L of the
IPA liquid is formed is transferred to the drying process unit 17
by the substrate transfer device 18.
[0138] Next, a substrate process according to the second embodiment
will be described with reference to FIG. 12. FIG. 12 is a flowchart
illustrating the substrate process according to the second
embodiment.
[0139] The substrate processing system according to the second
embodiment performs a first transfer process (S30). The substrate
processing system according to the second embodiment transfers the
wafer W from the carrier C to the delivering part 14 using the
substrate transfer device 13.
[0140] The substrate processing system according to the second
embodiment measures a weight of the wafer W before a cleaning
process, namely before the liquid film L of the IPA liquid is
formed on the wafer W, using the load cell 43 (S31).
[0141] The substrate processing system according to the second
embodiment performs a second transfer process (S32). The substrate
processing system according to the second embodiment transfers the
wafer W from the delivering part 14 to the cleaning process unit 16
using the substrate transfer device 18.
[0142] The substrate processing system according to the second
embodiment performs the cleaning process (S33). The substrate
processing system according to the second embodiment removes
contaminants and subsequently performs a rinse-cleaning process.
Further, the substrate processing system according to the second
embodiment supplies the IPA liquid to the wafer W to form a liquid
film L of the IPA liquid on the front surface of the wafer W.
[0143] The substrate processing system according to the second
embodiment performs a third transfer process (S34). The substrate
processing system according to the second embodiment transfers the
wafer W from the cleaning process unit 16 to the drying process
unit 17 using the substrate transfer device 18. The substrate
processing system according to the second embodiment delivers the
wafer W onto the lifter pins 39a of the lifter 39A from the
substrate transfer device 18.
[0144] The substrate processing system according to the second
embodiment measures a weight of the wafer W on which the liquid
film L of the IPA liquid is formed, using the load cell 39c
(S35).
[0145] The substrate processing system according to the second
embodiment determines whether or not a liquid amount of the liquid
film L is normal (S36). If it is determined that the liquid amount
of the liquid film L is normal (Yes in S36), the substrate
processing system according to the second embodiment detects a
coating state (S37). The substrate processing system according to
the second embodiment measures a temperature of the wafer W using
the infrared sensor 60 and detects the coating state on the basis
of temperature distribution of the wafer W.
[0146] The substrate processing system according to the second
embodiment determines whether or not the coating state is normal
(S38). If it is determined that the coating state is normal (Yes in
S38), the substrate processing system according to the second
embodiment performs the drying process (S39).
[0147] If it is determined that the liquid amount of the IPA liquid
is abnormal (No in S36) or that the coating state is abnormal (No
in S38), the substrate processing system according to the second
embodiment transfers the wafer S to the regulating unit 50 so that
the regulating unit 50 regulates the liquid film L of the IPA
liquid formed on the wafer W (S40). The substrate processing system
according to the second embodiment transfers the wafer W having the
regulated liquid film L to the drying process unit 17 and measures
a weight of the wafer S (S35).
[0148] The substrate processing system according to the second
embodiment measures a weight of the wafer W after the drying
process using the load cell 39c (S41).
[0149] The substrate processing system according to the second
embodiment determines whether or not a dried state is normal (S42).
If it is determined that the dried state of the wafer W is abnormal
(No in S42), the substrate processing system 1 performs the
cleaning process again (S33).
[0150] If it is determined that the dried state of the wafer W is
normal (Yes in S42), the substrate processing system according to
the second embodiment performs a fourth transfer process (S43). The
substrate processing system according to the second embodiment
transfers the wafer W to the delivering part 14 using the substrate
transfer device 18, and subsequently transfers the wafer W to the
carrier C from the delivering part 14 using the substrate transfer
device 13.
[0151] The substrate processing system according to the second
embodiment detects the liquid amount of the liquid film L after the
wafer W on which the liquid film L of the IPA liquid is formed is
transferred to the drying process unit 17. Accordingly, the
substrate processing system according to the second embodiment can
detect the liquid amount of the liquid film L immediately before
the drying process. Therefore, it is possible to prevent the drying
process from being performed, for example, in a state where the
liquid amount of the liquid film L is small due to overflow or
volatilization of the IPA liquid in the course of transferring the
wafer W to the drying process unit 17A by the substrate transfer
device 18. Accordingly, the substrate processing system according
to the second embodiment can prevent the occurrence of pattern
collapse.
[0152] The substrate processing system according to the second
embodiment detects the coating state of the wafer W after the wafer
W on which the liquid film L of the IPA liquid is formed is
transferred to the drying process unit 17. Accordingly, the
substrate processing system according to the second embodiment can
detect the coating state of the wafer W immediately before the
drying process. Therefore, it is possible to prevent the drying
process from being performed, for example, in a state where the
defective portion Wa (see FIG. 7B) is generated in the liquid film
L of the IPA liquid due to overflow or volatilization of the IPA
liquid in the course of transferring the wafer W to the drying
process unit 17 by the substrate transfer device 18. Accordingly,
the substrate processing system according to the second embodiment
can prevent the occurrence of pattern collapse.
Third Embodiment
[0153] Next, a substrate processing system according to a third
embodiment will be described. Herein, the substrate processing
system according to the third embodiment will be described with a
focus on the differences from the substrate processing system
according to the second embodiment, and the description of the same
configuration as the substrate processing system according to the
second embodiment will be omitted. The substrate processing system
according to the third embodiment detects a coating state of the
wafer W on which the liquid film L of the IPA liquid is formed,
using an imaging device 72 instead of the infrared sensor 60.
<Outline of Drying Process Unit>
[0154] As shown in FIGS. 13 and 14, a drying process unit 17B
further includes a laser irradiation part 70, a screen 71, and the
imaging device 72. FIG. 13 is a schematic plan view of the drying
process unit 17B according to the third embodiment. FIG. 14 is a
schematic cross-sectional view showing a portion of the drying
process unit 17B taken along line XIV-XIV of FIG. 13.
[0155] The laser irradiation part 70 irradiates a laser beam to the
wafer W on which the liquid film L of the IPA liquid is formed and
that is held on the holding plate 32. The laser irradiation part 70
irradiates a plurality of laser beams to the wafer W. The laser
irradiation part 70 irradiates the laser beams to the wafer W held
on the holding plate 32 in a downwardly inclined direction.
[0156] The screen 71 is disposed to face the laser irradiation part
70 with the wafer W held on the holding plate 32 sandwiched between
the screen 71 and the laser irradiation part 70. Reflected beams
generated when the laser beams are reflected by the wafer W and the
holding plate 32 are projected on the screen 71.
[0157] For example, the imaging device 72 is disposed above the
laser irradiation part 70. The imaging device 72 is, for example, a
digital camera, and picks up the reflected beams projected on the
screen 71. Image data of the reflected beams picked up by the
imaging device 72 is transmitted to the control device 4.
[0158] The laser irradiation part 70 and the imaging device 72, and
the screen 71 are aligned in an X-axis direction. Further,
positions of the laser irradiation part 70 and the imaging device
72, and the screen 71 are not limited to the above arrangement. For
example, the laser irradiation part 70 and the imaging device 72,
and the screen 71 may be aligned in a Y-axis direction.
[0159] In the drying process unit 17B, the wafer W on which the
liquid film L of the IPA liquid is formed on is mounted on the
holding plate 32 by the lifter 39A (see FIG. 10A, etc.), and
subsequently, the laser beams are irradiated to the wafer W from
the laser irradiation part 70. The drying process unit 17B picks up
the reflected beams projected on the screen 71 using the imaging
device 72.
[0160] In some embodiments, the drying process unit 17B may pick up
reflected beams generated by irradiating the laser beams with
respect to the wafer W supported by the lifter 39A.
[0161] When the laser beams are irradiated in a downwardly inclined
direction to the wafer W on which the liquid film L of the IPA
liquid is formed, the laser beams are refracted at an interface
between the IPA liquid and the air and then reflected by the wafer
W. Further, the reflected beams are emitted from the IPA liquid, as
indicated by solid lines in FIG. 15. FIG. 15 is a schematic view
showing a state where the laser beams are reflected from the wafer
W on which the liquid film L of the IPA liquid is formed.
[0162] A laser beam incident on an edge portion L1 of the liquid
film L made of the IPA liquid has various optical conditions such
as an incident angle and a refraction angle, which are different
from laser beams incident on a central portion inward of the edge
portion L1 of the wafer W. Accordingly, for example, the laser beam
incident on the edge portion L1 of the liquid film L of the IPA
liquid at the side of the laser irradiation part 70 is totally
reflected at the interface between the liquid film L of the IPA
liquid and the air, as indicated by a dotted line in FIG. 15.
[0163] As described above, the reflected beam of the laser beam
incident on the edge portion L1 of the liquid film L of the IPA
liquid shows a behavior different from those of the laser beams
incident on portions closer to the central side rather than the
edge portion L1 of the wafer W. Accordingly, depending to the edge
portion L1 of the liquid film of the IPA liquid, an area with low
intensity of light or an area in which the reflected beams are
disturbed (hereafter, referred to as "disturbed area") is
manifested on the reflected beams projected onto the screen 71.
[0164] For example, in the case where no defective portion Wa is
generated in the liquid film L of the IPA liquid, a substantially
elliptical disturbed area is manifested on the screen 71 depending
to the edge portion L1 of a circular liquid film L of the IPA
liquid, as indicated by dots in FIG. 16A. FIG. 16A is a schematic
view showing the reflected beams in the state where no defective
portion Wa is not generated in the liquid film L of the IPA liquid.
Further, in FIG. 16A, reflected beams generated at the portions
closer to the central side rather than the edge portion L1 of the
liquid film L of the IPA liquid are indicated by dotted lines, and
reflected beams reflected at the holding plate 32 are indicated by
solid lines.
[0165] Meanwhile, in the case where the defective portion Wa is
generated in the liquid film L of the IPA liquid, as shown in a
circle in FIG. 16B, an uneven disturbed area corresponding to the
defective portion Wa is manifested instead of showing the disturbed
area in a substantially elliptical shape. FIG. 16B is a schematic
view showing the reflected beams in the case where the defective
portion Wa is generated in the liquid film L of the IPA liquid.
Further, in FIG. 16B, the disturbed area is indicated by dots, the
reflected beams reflected at the portions closer to the central
side rather than the edge portion L1 of the liquid film L of the
IPA liquid are indicated by dotted liens, and reflected beams
reflected at the holding plate 32 or the wafer W are indicated by
solid lines.
[0166] Thus, it is possible to detect whether or not the defective
portion Wa is generated by irradiating laser beams to the wafer W
on which the liquid film L of the IPA liquid is formed and picking
up the reflected beams projected onto the screen 71.
<Configuration of Control Device>
[0167] As shown in FIG. 17, an image data obtained by picking up
the reflected beams by the imaging device 72 is inputted to the
control part 19 of the control device 4. FIG. 17 is a schematic
block diagram of the control device 4 according to the third
embodiment.
[0168] The coating state detecting part 19B detects a coating state
of the wafer W on the basis of the image data of the reflected
beams, which is obtained by the imaging device 72. Specifically,
the coating state detecting part 19B compares an image data of
reflected beams, which is picked up in a state where no defective
portion Wa is generated in the liquid film L of the IPA liquid, and
an image data of reflected beams, which is picked up in the current
process, and detects the coating state of the wafer W based on the
comparison result. Further, the image data of the reflected beams,
which is picked up in the state where no defective portion Wa is
generated in the liquid film L of the IPA liquid, is stored in
advance in the memory part 20.
[0169] The determining part 19C determines whether or not the
coating state of the wafer W is normal. Specifically, the
determining part 19C determines whether the defective portion Wa
exists in a predetermined area on the basis of the detection result
obtained by the coating state detecting part 19B.
<Substrate Process>
[0170] A substrate process according to the third embodiment will
be described with a focus on the differences from the substrate
process according to the second embodiment, and the description of
the same process as the substrate process according to the second
embodiment will be omitted.
[0171] The substrate process of a substrate processing system
according to the third embodiment includes detecting a coating
state of the wafer W on the basis of the image data of obtained by
picking up reflected beams by the imaging device 72 (S37).
[0172] The substrate processing system according to the third
embodiment irradiates the laser beams to the wafer W on which the
liquid film L of the IPA liquid is formed, using the laser
irradiation part 70, and picks up the reflected beams projected
onto the screen 71 using the imaging device 72. Further, the
substrate processing system according to the third embodiment
detects the coating state of the wafer W on the basis of the
obtained image data of the reflected beams.
[0173] Accordingly, when the defective portion Wa is generated in
the liquid film L of the IPA liquid, the substrate processing
system according to the third embodiment can accurately detect the
generation of the defective portion Wa. Further, the substrate
processing system according to the third embodiment can prevent the
drying process from being performed in the state where the
defective portion Wa is generated in the liquid film L of the IPA
liquid. Accordingly, the substrate processing system according to
the third embodiment can suppress the occurrence of pattern
collapse.
Fourth Embodiment
[0174] Next, a substrate processing system according to a fourth
embodiment will be described. Here, the substrate processing system
according to the fourth embodiment will be described with a focus
on the differences from the substrate processing system according
to the second embodiment, and the description of the same
configuration as the substrate processing system according to the
second embodiment will be omitted. The substrate processing system
according to the fourth embodiment detects a coating state of the
wafer W on which the liquid film L of the IPA liquid is formed,
using an imaging device 72 instead of the infrared sensor 60.
<Outline of Drying Process Unit>
[0175] As shown in FIGS. 18 and 19, a drying process unit 17C
according to the fourth embodiment further includes a monochromatic
beam irradiating part 75 and an imaging device 72. FIG. 18 is a
schematic plan view of the drying process unit 17C according to the
fourth embodiment. FIG. 19 is a schematic cross-sectional view
showing a portion of the drying process unit 17C taken along line
XIX-XIX of FIG. 18.
[0176] The monochromatic beam irradiating part 75 is, for example,
a sodium lamp. The monochromatic beam irradiating part 75
irradiates monochromatic beams to the wafer W on which the liquid
film L of the IPA liquid is formed and that is held on the holding
plate 32. The monochromatic beam irradiating part 75 irradiates the
monochromatic beams to the wafer W held on the holding plate 32 in
a downwardly inclined direction.
[0177] The imaging device 72 is disposed to face the monochromatic
beam irradiating part 75 with the wafer W held on the holding plate
32 sandwiched between the imaging device 72 and the monochromatic
beam irradiating part 75. The imaging device 72 picks up the wafer
W on which the liquid film L of the IPA liquid is formed. Image
data of the wafer W picked up by the imaging device 72 is
transmitted to the control device 4.
[0178] The drying process unit 17C mounts the wafer W on which the
liquid film L of the IPA liquid is formed on the holding plate 32
by the lifter 39 (see FIG. 10A, etc.) and irradiates the
monochromatic beams to the wafer W using the monochromatic beam
irradiating part 75. The drying process unit 17C picks up the image
of the wafer W using the imaging device 72.
[0179] In some embodiments, the drying process unit 17C may pick up
the image of the wafer W by radiating the monochromatic beams to
the wafer W supported by the lifter 39.
[0180] When the monochromatic beams are irradiated to the wafer W
on which the liquid film L of the IPA liquid is formed in a
downwardly inclined direction, an interference pattern is generated
by interference between reflected beams generated when the
monochromatic beams are reflected at a front surface of the liquid
film L of the IPA liquid, and reflected beams generated when the
monochromatic beams are reflected at the wafer W and then emitted
from the liquid film L of the IPA liquid. The imaging device 72
picks up the interference pattern generated due to the liquid film
L of the IPA liquid.
[0181] For example, in a case where the imaging device 72 is
disposed in the vicinity of a point E shown in FIG. 20, an
interference pattern according to a path difference (ACD-BD) is
generated. FIG. 20 is a view illustrating the generation principle
of the interference pattern.
[0182] Assuming that a film thickness of the liquid film L is d, a
refractive index of the liquid film L is n, a refractive index of
the air is 1.0, and an incident angle is .theta., an optical path
difference according to the path difference is defined as 2nd cos
.theta..
[0183] When the optical path difference satisfies the condition of
the following Equation 1, bright lines are generated by
interference between the reflected beams reflected at the front
surface of the liquid film L of the IPA liquid and the reflected
beams reflected at the wafer W and then emitted from the liquid
film L of the IPA liquid.
2nd cos .theta.=(m+1/2)).lamda. (1)
where, .lamda. is the wavelength of a monochromatic beam, and m is
an integer.
[0184] On the other hand, when the optical path difference
satisfies the condition of the following Equation 2, dark lines are
generated by interference between the reflected beams reflected at
the front surface of the liquid film L of the IPA liquid and the
reflected beams reflected at the wafer W and then emitted from the
liquid film L of the IPA liquid.
2nd cos .theta.=m.lamda. (2)
[0185] As described above, the dark lines are generated at a
portion where the optical path difference is an integer multiple of
the wavelength .lamda. of the monochromatic beam, and the bright
lines are generated at a portion where the optical path difference
is deviated by a half wavelength from the wavelength .lamda. of the
monochromatic beam. This causes the interference pattern. Further,
the interference pattern is dependent upon the film thickness d of
the IPA liquid formed on the wafer W.
[0186] For these reasons, in the case where no defective portion Wa
is generated in the liquid film L of the IPA liquid, when the
monochromatic beams are irradiated to the IPA liquid formed on the
circular wafer W, a substantially elliptical interference pattern
is generated as indicated by a dashed-dotted line in FIG. 21A. FIG.
21A is a schematic view of the wafer W in which no defective
portion Wa is generated in the liquid film L of the IPA liquid, as
obliquely viewed from the top.
[0187] On the other hand, in the case where the defective portion
Wa is generated in the liquid film L of the IPA liquid, when the
monochromatic beams are irradiated to the IPA liquid formed on the
circular wafer W, an interference pattern having a portion formed
to be partially concave toward the central side of the wafer W
according to the defective portion Wa is generated, as indicated by
a dashed-dotted line in FIG. 21B. FIG. 21B is a schematic view of
the wafer W in which the defective portion Wa is generated in the
liquid film L of the IPA liquid, as obliquely viewed from the
top.
[0188] As described above, it is possible to detect the presence of
absence of the defective portion Wa by irradiating the
monochromatic beams to the wafer W on which the liquid film L of
the IPA liquid is formed and picking up the interference pattern
thus generated.
<Configuration of Control Device>
[0189] The configuration of the control device 4 according to the
fourth embodiment will be described with reference to the block
diagram of FIG. 17, with a focus on the differences from the
control device 4 according to the third embodiment, and the
description of the same configuration as the control device 4
according to the third embodiment will be omitted.
[0190] Image data obtained by picking up the wafer W using the
imaging device 72 is inputted to the control part 19 of the control
device 4.
[0191] The coating state detecting part 19B detects a coating state
of the wafer W on the basis of the image data of the wafer W
obtained by the imaging device 72. Specifically, the coating state
detecting part 19B compares an image data obtained by picking up
the wafer W in which no defective portion Wa is generated in the
liquid film L of the IPA liquid, and an image data obtained by
picking up the wafer W in the current process, and detects the
coating state of the wafer W based on the comparison result.
Further, the image data obtained by picking up the wafer W in which
no defective portion Wa is generated in the liquid film L of the
IPA liquid, is stored in advance in the memory part 20.
[0192] The substrate processing system according to the fourth
embodiment irradiates the monochromatic beams to the wafer W on
which the liquid film L of the IPA liquid is formed, using the
monochromatic beam irradiating part 75 such as a sodium lamp, and
picks up the wafer W using the imaging device 72. Further, the
substrate processing system detects the coating state of the wafer
W on the basis of the obtained image data of the wafer W.
[0193] Accordingly, when the defective portion Wa is generated in
the liquid film L of the IPA liquid, the substrate processing
system according to the fourth embodiment can accurately detect the
generation of the defective portion Wa. Further, the substrate
processing system according to the fourth embodiment can prevent
the drying process from being performed in the state where the
defective portion Wa is generated in the liquid film L of the IPA
liquid. Therefore, the substrate processing system according to the
fourth embodiment can suppress the occurrence of pattern
collapse.
Modified Example
[0194] When a liquid amount of the liquid film L is too small, when
the defective portion Wa generated in the liquid film L of the IPA
liquid is large, or when many defective portions Wa are generated
in the liquid film L of the IPA liquid, a substrate processing
system according to a modified example may determine that pattern
collapse has occurred in the wafer W and may handle the wafer W as
a defective wafer. For example, the substrate processing system
according to the modified example determines whether pattern
collapse has occurred by comparing the liquid amount of the liquid
film L and the generation level of the defective portion Wa with
predetermined respective threshold values. Accordingly, it is
possible to prevent the regulation of the liquid amount of the IPA
liquid in the wafer W having pattern collapse, thus efficiently
performing the substrate process.
[0195] For example, when the liquid amount of the liquid film L is
larger than an upper limit value in a first predetermined range,
the substrate processing system according to the modified example
may increase the exhaust amount of the supercritical fluid in the
drying process unit 17. Accordingly, the substrate processing
system according to the modified example can suppress the
generation of particles without regulating the liquid amount of the
IPA liquid.
[0196] In the substrate processing system according to the modified
example, the load cell, the infrared sensor and the like may be
installed in the cleaning process unit 16 and the drying process
unit 17. With this configuration, the substrate processing system
according to the modified example can transfer the wafer W from the
cleaning process unit 16 in a state where the liquid amount of the
liquid film L and the coating state are normal. Accordingly, after
the wafer W is transferred to the drying process unit 17, if the
liquid amount of the liquid film L or the coating state is
abnormal, it may be possible to determine that a problem occurs in
the course of transferring the wafer W from the cleaning process
unit 16 to the drying process unit 17. That is to say, it is
possible to easily specify a cause of the occurrence of the
problem.
[0197] In the substrate processing system according to the modified
example, the load cell may be installed in the substrate transfer
device 18. This reduces the number of load cells used in the
substrate processing system. Further, in the substrate processing
system according to the modified example, the infrared sensor 27,
the imaging device 72 and the like may be installed in the cleaning
process unit 16, and the load cell 39c may be installed in the
drying process unit 17.
[0198] The substrate processing system according to the modified
example may compare a weight of the wafer W on which the liquid
film L of the IPA liquid is formed with a first preset weight and
determine whether a liquid amount of the liquid film L is normal.
Further, the substrate processing system according to the modified
example may compare a weight of the wafer W after the drying
process with a second preset weight and determine whether a dried
state is normal. With this configuration, it is possible to
determine whether the liquid amount of the liquid film L or the
dried state is normal without installing the load cell 43 in the
delivering part 14. This reduces the number of load cells used in
the substrate processing system.
[0199] The substrate processing system according to the modified
example may measure a temperature of the wafer W using the infrared
sensor 60, for example, in a state where the wafer W is received in
the main body 31 of the drying process unit 17A according to the
second embodiment. With this configuration, even in a case where
hardly a temperature of the entire area of the wafer W mounted on
the holding plate 32 is measured, it is possible to measure the
temperature of the entire area of the wafer W using a single
infrared sensor 60.
[0200] Further, the substrate processing system according to the
modified example, for example, may irradiate laser beams toward the
wafer W using the laser irradiation part 70 in a state where the
wafer W is received in the main body 31 of the drying process unit
17B according to the third embodiment. In this case, as shown in
FIG. 22, the laser irradiation part 70 may be disposed anywhere as
long as it can irradiate a single laser beam to an edge of the
wafer W close to the main body 31. FIG. 22 is a schematic plan view
of the drying process unit 17D of the substrate processing system
according to the modified example.
[0201] Further, the substrate processing system according to the
modified example may continuously pick up the reflected beams
projected onto the screen 71 using the imaging device 72 in a state
where the wafer W is received in the main body 31. The substrate
processing system according to the modified example can obtain the
entire image data of the reflected beams throughout the wafer W by
combining image data obtained in the above manner With this
configuration, it is possible to detect the coating state of the
wafer W using the laser irradiation part 70 that irradiates a
single laser beam.
[0202] Further, the substrate processing system according to the
modified example may pick up the reflected beams projected onto the
screen 71 using the imaging device 72, before mounting, on the
holding plate 32, the wafer W on which the liquid film L of the IPA
liquid is formed, for example, in the state where the wafer W is
mounted on the lifter 39A (see FIG. 10A, etc.).
[0203] Further, the substrate processing system according to the
modified example may detect a coating state in accordance with a
change in an interference pattern in the drying process unit 17C of
the fourth embodiment. The IPA liquid formed on the wafer W
evaporates over time. Thus, a film thickness d of the liquid film L
of the IPA liquid becomes thinner over time. That is to say, a
position where an interference pattern as a function of the film
thickness d of the liquid film L of the IPA liquid is changed over
time. However, since no IPA liquid exists and no interference
pattern is generated, there is no change of the defective portion
Wa in the image even with time.
[0204] As described above, the substrate processing system
according to the modified example may detect a coating state on the
basis of the change in the interference pattern. Accordingly, the
substrate processing system according to the modified example can
detect the coating state of the wafer W.
[0205] In some embodiments, the substrate processing system
according to the modified example may pick up the wafer W on which
the liquid film L of the IPA liquid is formed, using the imaging
device 72, and detect a coating state of the wafer W on the basis
of image data obtained by the picking up. Further, the substrate
processing system according to the modified example may pick up the
wafer W after the drying process using an imaging device such as a
camera, and detect a surface state of the wafer W after the drying
process on the basis of image data thus obtained. Accordingly, the
substrate processing system according to the modified example can
more accurately determine the surface state of the wafer W after
the drying process, specifically whether the wafer W has been
sufficiently dried.
[0206] Further, the substrate processing system according to the
modified example may pick up the wafer W on which the liquid film L
of the IPA liquid is formed, using a camera, and estimate a liquid
amount of the liquid film L formed on the wafer W on the basis of
image data thus obtained.
[0207] In the substrate processing system according to the modified
example, when the dried state of the wafer W is abnormal, the wafer
W of which the dried state is abnormal may be discarded as a
defective wafer. Further, when the dried state of the wafer W is
abnormal, for example, when the wafer W has not been sufficiently
dried, the substrate processing system according to the modified
example may perform the drying process again.
[0208] Further, the method of detecting the liquid amount, the
method of detecting the coating state, and the method of detecting
the dried state of the wafer W are not limited to be applied to the
substrate processing system including the drying process unit that
uses the supercritical fluid. As an example, such methods may be
applied to various substrate processing systems that form a liquid
film of a liquid on a wafer W and then dry the wafer.
[0209] Further, the substrate processing systems according to the
above embodiments and the substrate processing system according to
the modified example may be appropriately combined with each other
in configuration.
[0210] According to the present disclosure in some embodiments, it
is possible to improve the yield of a substrate.
[0211] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the disclosures. Indeed, the
embodiments described herein may be embodied in a variety of other
forms. Furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the disclosures. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
disclosures.
* * * * *