U.S. patent application number 10/045062 was filed with the patent office on 2002-09-12 for photoresist stripper composition and method for stripping photoresist using the same.
Invention is credited to Chun, Sang-Mun, Jeon, Mi-Sook, Jun, Pil-Kwon, Kil, June-Ing, Moon, Sang-Sik, Park, Je-Eung.
Application Number | 20020127500 10/045062 |
Document ID | / |
Family ID | 19614522 |
Filed Date | 2002-09-12 |
United States Patent
Application |
20020127500 |
Kind Code |
A1 |
Moon, Sang-Sik ; et
al. |
September 12, 2002 |
Photoresist stripper composition and method for stripping
photoresist using the same
Abstract
A photoresist stripper composition is formed of a mixture of
acetone, .gamma.-butyrolactone, and ester solvent. A photoresist
stripping method includes spraying the photoresist stripper
composition over a substrate while rotating the substrate at a
relatively low speed, so as to strip photoresist from the
substrate. The rotation of the substrate is stopped for a short
period of time, and thereafter the photoresist stripper composition
is again sprayed over the substrate while rotating the substrate at
a relatively high speed. Then, the substrate is rinsed with pure
water.
Inventors: |
Moon, Sang-Sik;
(Yongin-city, KR) ; Jeon, Mi-Sook; (Yongin-city,
KR) ; Jun, Pil-Kwon; (Yongin-city, KR) ; Kil,
June-Ing; (Yongin-city, KR) ; Park, Je-Eung;
(Yongin-city, KR) ; Chun, Sang-Mun; (Yongin-city,
KR) |
Correspondence
Address: |
VOLENTINE FRANCOS, PLLC
SUITE 150
12200 SUNRISE VALLEY DRIVE
RESTON
VA
20191
US
|
Family ID: |
19614522 |
Appl. No.: |
10/045062 |
Filed: |
January 15, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10045062 |
Jan 15, 2002 |
|
|
|
09679558 |
Oct 6, 2000 |
|
|
|
Current U.S.
Class: |
430/329 ;
257/E21.255; 430/331; 510/176 |
Current CPC
Class: |
H01L 21/31133 20130101;
G03F 7/422 20130101; C11D 11/0047 20130101; C11D 7/5022
20130101 |
Class at
Publication: |
430/329 ;
430/331; 510/176 |
International
Class: |
G03F 007/42 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 8, 1999 |
KR |
99-43486 |
Claims
What is claimed is:
1. A photoresist stripper composition comprising a mixture of
acetone, .gamma.-butyrolactone, and an ester solvent.
2. The photoresist stripper composition of claim 1, wherein the
ester solvent comprises acetic acid ester.
3. The photoresist stripper composition of claim 2, wherein the
ester solvent comprises at least one selected from the group
consisting of n-butyl acetate, amyl acetate, ethyl acetoacetate,
isopropyl acetate and propylene glycol monomethyl ether
acetate.
4. The photoresist stripper composition of claim 1, wherein, based
on a total weight of the mixture, the mixture comprises: 3 to 35%
by weight acetone; 2 to 13% by weight .gamma.-butyrolactone; and 55
to 95% by weight ester solvent.
5. The photoresist stripper composition of claim 1, wherein, based
on a total weight of the mixture, the mixture comprises: 8 to 15%
by weight acetone; 4 to 7% by weight .gamma.-butyrolactone; and 80
to 90% by weight ester solvent.
6. The. photoresist stripper composition of claim 1, further
comprising a surfactant.
7. A photoresist stripping method comprising: spraying a
photoresist stripper composition comprising a mixture of acetone,
.gamma.y-butyrolactone and an ester solvent, over a substrate while
rotating the substrate at a first speed, so as to strip photoresist
from the substrate; stopping the rotation of the substrate for a
period of time; spraying the photoresist stripper composition over
the substrate while rotating the substrate at a second speed which
is higher than the first speed; and rinsing the substrate with pure
water.
8. The photoresist stripping method of claim 7, further comprising
spin drying the substrate after said stopping the rotation of the
substrate and before said spraying the photoresist stripper
composition while rotating the substrate at the second speed.
9. The photoresist stripping method of claim 7, further comprising
spin drying the substrate after said spraying the photoresist
stripper composition while rotating the substrate at the second
speed and before said rinsing the substrate with pure water.
10. The photoresist stripping method of claim 7, wherein the first
speed is 1200 to 1500 rpm.
11. The photoresist stripping method of claim 7, wherein the second
speed is 2000 to 2500 rpm.
12. The photoresist stripping method of claim 7, wherein said
spraying the photoresist stripper composition while rotating the
substrate at the first speed step is carried out for 10 to 20
seconds.
13. The photoresist stripping method of claim 7, wherein the period
of time is 20 to 30 seconds.
14. The photoresist stripping method of claim 7, wherein said
spraying the photoresist stripper composition while rotating the
substrate at the second speed step is carried out for 10 to 20
seconds.
15. The photoresist stripping method of claim 7, wherein, based on
a total weight of the mixture, the mixture comprises: 3 to 35% by
weight acetone; 2 to 13% by weight .gamma.-butyrolactone; and 55 to
95% by weight ester solvent.
16. The photoresist stripping method of claim 7, the photoresist
stripper composition further comprising a surfactant.
17. The photoresist stripping method of claim 7, wherein the ester
solvent contained in the photoresist stripper composition comprises
at least one selected from the group consisting of n-butyl acetate,
amyl acetate, ethyl acetoacetate, isopropyl acetate and propylene
glycol monomethyl ether acetate.
18. The photoresist stripping method of claim 7, wherein based on a
total weight of the mixture, the mixture comprises: 8 to 15% by
weight acetone; 4 to 7% by weight .gamma.-butyrolactone; and 80 to
90% by weight n-butyl acetate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a photoresist stripper
composition for use in removing photoresist from a substrate such
as a silicon wafer, and to a method for stripping photoresist using
the photoresist stripper composition.
[0003] 2. Description of the Related Art
[0004] In the manufacture of semiconductor devices such as
integrated circuits (ICs), large scale integrated circuits (LSIs),
and liquid crystal displays (LCDs), photoresists are extensively
used as a coating mask material. In a common method for fabricating
ICs by photolithography with a photoresist, the photoresist is
evenly deposited on a conductive metal layer or a dielectric layer
formed on a substrate, so that a photoresist layer is formed
thereon. Then, the solvent contained in the photoresist layer is
vaporized by a soft baking process so as to stabilize the
photoresist layer. After the soft baking process, the photoresist
layer is exposed to UV radiation, electron-beams, X-rays and so
forth, and then subjected to a developing process to form a
photoresist pattern on the substrate. Following this, the
underlying conductive metal layer or the dielectric layer is
selectively etched using the photoresist pattern as a mask, thereby
forming fine circuit patterns. Thereafter, the photoresist is
removed using a stripper.
[0005] In the photolithography process, it is also important to
remove photoresist present on the edge or backside of the wafer
after the soft baking process. Otherwise, defects can occur during
a subsequent etching or ion implantation process, thereby lowering
yield. A stripper containing an organic solvent is commonly used
for this purpose.
[0006] Likewise, wafers undergoing reworking, which have been
previously identified as defective or which have been set aside for
testing, must also have photoresist removed by application of a
stripper.
[0007] When the photoresist pattern from the developing process is
subjected to post exposure baking (PEB) at a high temperature, ion
implantation and DUV radiation, the photoresist pattern is
hardened, and made more resistant to an organic solvent by
cross-linking.
[0008] In removing the cured photoresist material, a solvent
containing halogenated hydrocarbons and phenolic hydrocarbons has
been used in the prior art. However, use of such solvents is
disfavored because it causes hazardous working conditions and
environmental concerns over the handling of waste matter.
[0009] Also, acidic or alkali strippers can be used to remove the
cured photoresist material. However, the acidic or alkali strippers
can corrode an underlying metal on the substrate, which may be an
aluminum (Al) layer, or a metal alloy layer containing copper (Cu)
or tungsten (W). This may limit the capacity for forming
microminiature interconnection patterns.
[0010] When a common organic solvent is used as a photoresist
stripper, an organic solvent such as isopropyl alcohol must be used
as a rinsing solution. Thus, the rinsing process becomes
complicated and the safety concerns arise.
[0011] Some conventional chemicals or solvents for use as a
photoresist stripper have a very slow dissolution rate over the
cured photoresist, or cause incomplete dissolution over the same.
Such photoresist residues from the stripping process are not
removed completely during subsequent processes, thereby adversely
effecting the reliability of a device in terms of its electrical
properties.
[0012] Therefore, there is a need for a photoresist stripper which
is capable of completely and quickly removing the cured photoresist
from the substrate without causing damage or contamination to the
substrate.
[0013] Also, as the integration density of semiconductor devices
increases, the fabrication of semiconductor devices becomes
complicated by the need for fine line pattern formation. 1-Gigabit
or more semiconductor devices, in which a pattern size has a design
rule of 0.2 .mu.m or less, cannot be achieved by a conventional
resist which is sensitive to light from a KrF eximer laser (248
nm). For this reason, a novel photolithography technique using an
ArF eximer laser (193 nm) as an exposure light source has been
introduced.
[0014] Therefore, there is a need for a photoresist stripper
composition capable of being used, regardless of the polarity of
photoresist, for a variety of photoresists including conventional
photoresists, such as i-line resist and G-line resist, which
contain Cresol Novolak Resin as a major component, and chemically
amplified resists sensitive to an eximer laser or a DUV exposure
light source, with the photoresist stripper composition also having
a high solubility with respect these photo resists.
SUMMARY OF THE INVENTION
[0015] It is a first objective of the present invention to provide
a photoresist stripper composition which is capable of effectively
and quickly stripping photoresist coated on a substrate regardless
of the kind and the polarity of the photoresist.
[0016] It is a second objective of the present invention to provide
a photoresist stripper composition which is capable of efficiently
and safely stripping photoresist coated on a substrate, either
cured or uncured, without causing damage or contamination to an
underlying layer.
[0017] It is a third objective of the present invention to provide
a photoresist stripper composition which is capable of effectively
and efficiently stripping photoresist from a wafer during a rinsing
step on the edge or backside of the wafer, or during a reworking
process on wafers which have defects or which were previously used
for testing.
[0018] It is a fourth objective of the present invention to provide
a method for stripping photoresist, by which photoresist can be
effectively removed from a substrate without the need of performing
an additional rinsing process with an organic solvent after
stripping.
[0019] To achieve the above objectives of the present invention,
there is provided a photoresist stripper composition comprising a
mixture of acetone, .gamma.-butyrolactone, and an ester
solvent.
[0020] Preferably, the ester solvent comprises acetic acid ester.
Preferably, the ester solvent comprises at least one selected from
the group consisting of n-butyl acetate, amyl acetate, ethyl
acetoacetate, isopropyl acetate and propylene glycol monomethyl
ether acetate.
[0021] Preferably, the mixture of the photoresist stripper
composition comprises: 3 to 35% by weight acetone; 2 to 13% by
weight .gamma.-butyrolactone; and 55 to 95% by weight ester
solvent, based on the total weight of the mixture.
[0022] More preferably, the mixture of photoresist stripper
composition comprises: 8 to 15% by weight acetone; 4 to 7% by
weight .gamma.-butyrolactone; and 80 to 90% by weight ester
solvent, based on the total weight of the mixture.
[0023] Preferably, the photoresist stripper composition further
comprises a surfactant.
[0024] According to another aspect of the present invention, there
is provided a photoresist stripping method comprising spraying a
photoresist stripper composition comprising a mixture of acetone,
.gamma.-butyrolactone and an ester solvent, over a substrate while
rotating the substrate at a relatively low speed, so as to strip
photoresist from the substrate. The rotation of the substrate is
stopped for a short period of time, and thereafter the photoresist
stripper composition is sprayed over the substrate while rotating
the substrate at a relatively high speed. Then, the substrate is
rinsed with pure water.
[0025] Preferably, after stopping the rotation of the substrate for
a short period of time, the photoresist stripping method further
comprises spin drying the substrate.
[0026] Preferably, after spraying the photoresist stripper
composition over the substrate while rotating the substrate at a
relatively high speed, the photoresist stripping method further
comprises spin drying the substrate.
[0027] The photoresist stripper composition according to the
present invention is effective in removing a variety of
photoresists at room temperature. Also, the photoresist stripper
composition has a rapid dissolution rate and is very volatile, and
thus it does not remain on the surface of the wafer after
stripping. In addition, the method for stripping photoresist with
the photoresist stripper composition can completely remove
photoresist from the wafer surface, and is itself removed by simple
rinsing step with water, thereby simplifying the overall
process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The above objectives and advantages of the present invention
will become more apparent by describing in detail a preferred
embodiment thereof with reference to the attached drawings in
which:
[0029] FIG. 1 is a sectional view showing the major parts of a
common nozzle spray type stripper unit; and
[0030] FIG. 2 is a flowchart illustrating a method for stripping
photoresist according to a preferred embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] The present invention provides an organic solvent based
photoresist stripper composition. The photoresist stripper
composition according to the present invention, which is a mixture
of acetone, .gamma.-butyrolactone and an ester solvent, is
effectively applicable with respect to various kinds of
photoresists at room temperature (in the range of 20 to 40.degree.
C.).
[0032] Each component of the photoresist stripper composition
according to the present invention can act as a stripper.
[0033] .gamma.-butyrolactone, which is known as a synthetic resin
solvent, has a high ignition point and is relatively stable as a
solvent. The safety of .gamma.-butyrolactone is evidenced by
results obtained from a skin test and a 3-month intake that
indicate no toxic effect on the human body. Some physical
properties of .gamma.-butyrolactone include: specific gravity of
1.128, boiling point of 204.degree. C., ignition point of
98.degree. C. at near vacuum pressure and 457.degree. C. at
atmospheric pressure, and viscosity of 1.70 cP at 25.degree. C.
[0034] Acetone is soluble in ether and is widely known as a solvent
for resin, rubber, plastic, pigment and the like, and as a
dissolution agent for acetylene. Some physical properties of
acetone include: specific gravity of 0.792, boiling point of
56.5.degree. C., ignition point of -15.degree. C. at near vacuum
pressure and 465.degree. C. at atmospheric pressure, and viscosity
of 0.337 cP at 25.degree. C.
[0035] The photoresist stripper composition according to the
present invention uses acetic.acid esters as an organic
solvent.
[0036] The ester solvents, which can be used for the photoresist
stripper composition according to the present invention, include
n-butyl acetate, amyl acetate, ethyl acetoacetate, isopropyl
acetate and propylene glycol monomethyl ether acetate.
[0037] Preferably, the photoresist stripper composition according
to the present invention comprises: 3 to 35% by weight acetone,
with the preferred range being 8 to 15% by weight; 2 to 13% by
weight .gamma.-butyrolactone, with the preferred range being 4 to
7% by weight; and 55 to 95% by weight ester solvent, with the
preferred range being 80 to 90% by weight, based on the total
weight of the composition.
[0038] The photoresist stripper composition according to the
present invention may further comprise an auxiliary component, for
example, a surfactant, as needed.
[0039] The inventors found that the synergistic effects of each
component of the stripper composition allow for extensive use of
the photoresist stripper composition over any kind of photoresist,
and that a variety of different photoresists can be removed quickly
due to rapid dissolution rates of the composition.
[0040] In other words, the photoresist stripper composition
according to the present invention can effectively strip
photoresists formed of a variety of organic polymers, from the
substrate. Photoresists formed of organic polymers are basically
categorized into two types: negative-working photoresists and
positive-working photoresists. Depending on the radiation source,
these negative and positive working photoresists are classified
into G-line resists, i-line resists, deep ultraviolet (DUV)
resists, electron beam resists, X-rays resists, and ion beam
resists. The photoresist stripper composition according to the
present invention can effectively strip any of these
photoresists.
[0041] In the field of lithography, the composition of the layer
underlying the photoresist layer formed of organic polymers must be
considered when selecting an appropriate stripper composition. The
photoresist stripper composition according to the present invention
is applicable even when the underlying layer is formed of a metal
layer of, for example, aluminum, an aluminum alloy, copper or a
copper alloy, in addition to when the underlying layer is formed of
a common material layer such as a silicon layer, a silicon oxide
layer, a silicon nitride layer and a polysilicon layer. The
photoresist stripper composition according to the present invention
can effectively strip the photoresist without causing damage or
contamination to such underlying layers.
[0042] The dissolution abilities of components which can be used
for the photoresist stripper composition according to the present
invention were separately measured with respect to various
photoresists. The results are given in Table 1.
[0043] Table 1
1 Dissolution rate, .ANG./sec i-line resist DUV resist Component
SS880A7 UV III SEPR-402 SEPR-430S .gamma.-butyrolactone 15163 9180
8463 5600 Acetone 15163 9180 5633 6743 n-butyl acetate 2146 529 204
1388
[0044] In particular, the dissolution ability was tested for the
effective components, .gamma.-butyrolactone and acetone, of the
photoresist stripper composition according to the present
invention. The resists used for the test were one i-line resist
obtained as SS880A7 (Smimoto Co., Japan), and three DUV resists
obtained as UV III (Shipley Company Inc., Japan), SEPR-402
(ShinEtsu Co. Japan) and SEPR-430S (ShinEtsu Co., Japan). In
addition, n-butyl acetate, which is a typical organic solvent
available for the photoresist composition according to the present
invention, was subjected to the same test.
[0045] For the dissolution ability test, each resist was coated at
a sufficient thickness on a silicon wafer (at a wafer rotation
speed of 2000 rpm for 30 seconds) to prepare samples. The obtained
samples were soft baked at 160.degree. C. for 3 minutes, and
.gamma.-butyrolactone, acetone and n-butyl acetate were applied to
each of the samples. The dissolution rates for the components were
measured using a dissolution rate meter (DRM) at 25.degree. C. The
temperature of 25.degree. C. was maintained throughout the
measurement process.
[0046] The results of Table 1 show that each of the tested
components has a dissolution ability with respect to all resists
used for the test. All components tested for the photoresist
stripper composition according to the present invention show
relatively higher dissolution rates with respect to the i-line
resist, than the DUV resists.
[0047] It should be noted from Table 1 that each component having
dissolution ability with respect to various photoresists will
contribute to a synergistic effect in removing photoresist from a
wafer when incorporated into the photoresist stripper composition
according to the present invention. The synergistic effect of each
component in the photoresist stripper composition is evidenced from
Table 2.
[0048] Table 2 shows the dissolution ability of a particular
photoresist stripper composition according to the present invention
with respect to various photoresists. The particular photoresist
stripper composition tested was a mixture of 5% by weight
.gamma.-butyrolactone, 10% by weight acetone and 85% by weight
n-butyl acetate, based on the total weight of the mixture.
2TABLE 2 Initial Thickness of Resist Thickness Dissolution after 1
second of Resist of Resist, .ANG. Rate, .ANG./sec Dissolution,
.ANG. DUV SEPR-402 7000 >6800 0 resist SEPR-430 8300 >8300 0
UV III 5500 >5500 0 i-line ip-2680 16000 >16000 0 resist
ip-3300 12000 >12000 0 i-7010 32000 >32000 0 i-900 5000
>5000 0
[0049] The resists used for the dissolution ability test of the
photoresist stripper composition were DUV resists obtained as
SEPR-402 (ShinEtsu Co. Japan), SEPR-430 (ShinEtsu Co., Japan) and
UV III (Shipley Company Inc., Japan), and i-line resists obtained
as ip-2680 (Tokyo Ohka Kogyo Co., Japan), ip-3300 (Tokyo Ohka Kogyo
Co., Japan), i-7010 (Mitsubishi Denki Co., Japan) and i-900
(Dong-gin Chemicals Co., Korea).
[0050] For the dissolution ability test for the photoresist
stripper composition, each resist was coated on a silicon wafer to
be sufficiently thick (at a wafer rotation speed of 2000 rpm for 30
seconds) to prepare samples. The obtained samples were soft baked
at 160.degree. C. for 3 minutes, and the photoresist stripper
composition was spread over each of the wafers using a nozzle
spraying technique at 25.degree. C. Then, the dissolution rates of
the photoresist stripper composition with respect to the various
resists were measured using a dissolution rate meter (DRM). The
temperature of 25.degree. C. was maintained throughout the
measurement process.
[0051] Table 2 shows that all of the tested resists are completely
dissolved within 1 second with the photoresist stripper
composition. This result indicates that the mixture of stripper
components has synergetic effects in removing photoresists from a
wafer.
[0052] The photoresist stripper composition according to the
present invention can be used to remove photoresists adhering to or
coated on the surface of waters which were collected from a
photolithography process due to failure, or which were arbitrarily
extracted for process management testing, which allows for
recycling of the wafers.
[0053] The photoresist stripper composition according to the
present invention can also be effectively used to remove
photoresist from the edge or backside of a wafer after a soft
baking process.
[0054] In addition, the photoresist stripper composition according
to the present invention is also effective in stripping a cured
photoresist pattern, which remains after being used as an etching
mask to pattern the underlying layer by photolithography.
[0055] Hereinafter, a method for stripping photoresist using the
photoresist stripper composition according to the present invention
will be described with reference to the appended drawings.
[0056] FIG. 1 is a sectional view showing the major parts of a
common nozzle spray type stripper unit, which is available to
perform the photoresist stripping method according to the present
invention.
[0057] Referring to FIG. 1, a stripper unit 100 has a drain cup 10.
A spin chuck 12 for supporting a wafer W placed thereon is
installed in the drain cup 10. The spin chuck 12 is rotatable by
action of a rotor 14. A nozzle 22 is placed approximately over the
center of the spin chuck 12, to apply the photoresist stripper
composition through the nozzle 22 over the wafer W seated on the
spin chuck 12.
[0058] Also, the stripper unit 100 includes an edge rinsing nozzle
24 for spraying an edge rinsing solution over the wafer W. and a
backside rinsing nozzle 26 for spraying a backside rinsing solution
over the wafer W.
[0059] FIG. 2 is a flow diagram illustrating a preferred embodiment
of a method for stripping photoresist from a wafer according to the
present invention, using the stripper unit 100 shown in FIG. 1. The
photoresist stripping method according to the present invention,
which will now be described, is applicable to remove the
photoresist mask pattern from a wafer which was used as an etching
mask to pattern an underlying layer during a photolithography
process. The photoresist stripping method can also be applied in a
rework process for wafers, which were rejected after the
photolithography process due to defects or which were set aside for
process management testing.
[0060] The photoresist stripping method according to the present
invention includes a low-speed rotation stripping step 110, a
high-speed rotation stripping step 120 and a rinsing step S6. In
particular, in step 110, a substrate, for example, the silicon
wafer W, which is coated with photoresist, is put on the spin chuck
12 of the stripper unit 100 as shown in FIG. 1. Then, a photoresist
stripper composition is spread over the wafer W through the nozzle
22 for about 10 to 20 seconds while rotating the wafer W at a
relatively low speed of about 1200 to 1500 rpm (sub-step S1). Here,
because the water is rotating on the spin chuck 12, the photoresist
stripper composition is uniformly applied over the wafer W by
centrifugal force.
[0061] The photoresist stripper composition according to the
present invention, which was previously described, can be used for
the photoresist stripping process. In the present embodiment, the
photoresist stripper composition, a mixture of
.gamma.-butyrolactone, acetone and n-butyl acetate, is applied at
room temperature. As an example, the photoresist stripper
composition used in the present embodiment includes 5% by weight
.gamma.-butyrolactone, 10% by weight acetone and 85% by weight
n-butyl acetate, based on the total weight of the mixture.
[0062] Then, the rotation of the spin chuck 12 is stopped for about
20 to 30 seconds (sub-step S2). In sub-step S2, the photoresist on
the wafer W is dissolved by the photoresist stripper composition.
Following this, the spin chuck 12 is rotated at a higher speed, so
that the wafer W is spin dried (sub-step S3).
[0063] For removal of the photoresist residue from the wafer W, the
high-speed rotation stripping step 120 is carried out. In
particular, the photoresist stripper composition according to the
present invention is spread uniformly over the wafer W through the
nozzle 22 for about 10 to 20 seconds, while rotating the wafer W at
a relatively high speed of, for example, about 2000 to 2500 rpm
(sub-step S4). Following this, the spin chuck 12 is rotated at a
higher speed, so that the wafer W is spin dried (sub-step S5).
[0064] After the high-speed rotation stripping step 120, the wafer
W is subjected to a rinsing process with pure water to remove all
organic substances from the wafer W (step S6).
[0065] Then, the spin chuck 12 is rotated at a higher speed to spin
dry the wafer W, so that the pure water used in the rinsing step S6
is completely removed (step S7).
[0066] All of steps S1 through S7 described above can be performed
at room temperature.
[0067] The photoresist stripping method according to the present
invention involves two stages of stripping process, i.e., the
low-speed rotation stripping step 110 and the high-speed rotation
stripping step 120, and thus the photoresist can be completely
removed from the wafer W. Also, the photoresist stripping
composition according to the present invention is highly volatile,
so that nearly none of it remains on the wafer W after the removal
of the photoresist. The rinsing step S6 with pure water, which is
performed after the striping process, is sufficient to remove the
remaining organic substance from the surface of the wafer W,
without need to perform a rinse with an organic solvent such as
isopropyl alcohol (IPA). The rinsing step S6 is thus simplified in
the photoresist stripping method according to the present
invention.
[0068] The photoresist stripper composition according to the
present invention is applicable for a wafer edge rinse using the
edge rinsing nozzle 24 of the stripper unit 100 shown in FIG. 1. In
this case, the photoresist stripper composition according to the
present invention is spread on the edge of the wafer W through the
edge rinsing nozzle 24. As a result, the remaining photoresist is
uniformly removed from the edge of the wafer W in contact with the
stripper composition distributed through the edge rinsing nozzle
24, so that the surface of the wafer W becomes smooth.
[0069] On the other hand, the photoresist stripper composition
according to the present invention can be applied for a wafer
backside rinse using the backside rinsing nozzle 26 of the stripper
unit 100 shown in FIG. 1. As in the edge rinsing process, the
photoresist residue can be uniformly removed from the backside of
the wafer W, leaving a smooth surface free of organic solvents.
[0070] As described above, the photoresist stripper composition
according to the present invention is effectively applicable at
room temperature with respect to a variety of photoresists. The
photoresist stripper composition has a high dissolution rate and is
highly volatile, and thus the photoresist stripper composition
scarcely remains on the wafer surface. The photoresist stripper
composition according to the present invention can be effective in
a photoresist mask removing process, a rework process, a wafer edge
rinsing process, a wafer backside rinsing process and so forth.
[0071] The photoresist stripping method according to the present
invention can completely remove any photoresist from a wafer
through two stages of stripping process, i.e., a low-speed rotation
stripping step and a high-speed rotation stripping step. In
addition, the photoresist stripping method does not need to include
a step for rinsing with an organic solvent. Rather, the use of pure
wafer is sufficient to rinse organic substances from the wafer
surface. Therefore, the overall process can be simplified as
compared to a conventional stripping method which involves rinsing
with an organic solvent.
[0072] While this invention has been particularly shown and
described with reference to preferred embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made thereto without departing from the
spirit and scope of the invention as defined by the appended
claims.
* * * * *