U.S. patent application number 09/924092 was filed with the patent office on 2002-06-20 for pattern formation method.
Invention is credited to Endo, Masayuki, Sasago, Masaru.
Application Number | 20020076937 09/924092 |
Document ID | / |
Family ID | 18852723 |
Filed Date | 2002-06-20 |
United States Patent
Application |
20020076937 |
Kind Code |
A1 |
Endo, Masayuki ; et
al. |
June 20, 2002 |
Pattern formation method
Abstract
An anti-reflection film of an organic compound is formed on a
substrate. The anti-reflection film is weakened by carrying out
plasma processing on the anti-reflection film, and then, a resist
film is formed on the weakened anti-reflection film. The resist
film is subjected to pattern exposure and development so as to form
a resist pattern from the resist film. The anti-reflection film is
dry etched by using the resist pattern as a mask, so as to pattern
the anti-reflection film.
Inventors: |
Endo, Masayuki; (Osaka,
JP) ; Sasago, Masaru; (Osaka, JP) |
Correspondence
Address: |
NIXON PEABODY, LLP
8180 GREENSBORO DRIVE
SUITE 800
MCLEAN
VA
22102
US
|
Family ID: |
18852723 |
Appl. No.: |
09/924092 |
Filed: |
August 8, 2001 |
Current U.S.
Class: |
438/725 ;
257/E21.029; 257/E21.256; 438/928; 438/952 |
Current CPC
Class: |
H01L 21/31138 20130101;
H01L 21/0276 20130101; G03F 7/091 20130101 |
Class at
Publication: |
438/725 ;
438/952; 438/928 |
International
Class: |
H01L 021/302; H01L
021/461 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 19, 2000 |
JP |
2000-385463 |
Claims
What is claimed is:
1. A pattern formation method comprising the steps of: forming an
anti-reflection film of an organic compound on a substrate;
weakening said anti-reflection film by subjecting said
anti-reflection film to plasma processing; forming a resist film on
said weakened anti-reflection film; forming a resist pattern from
said resist film by subjecting said resist film to pattern exposure
and development; and patterning said anti-reflection film by dry
etching said anti-reflection film with said resist pattern used as
a mask.
2. The pattern formation method of claim 1, wherein said plasma
processing is carried out by using plasma seed including oxygen or
fluorine.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a pattern formation method
for patterning an anti-reflection film of an organic compound by
etching the anti-reflection film with a resist pattern used as a
mask.
[0002] In accordance with recent development in refinement of
semiconductor devices, it has become significant in the fabrication
process for semiconductor devices and the like to reduce exposing
light reflecting from a substrate for improving accuracy of a
resist pattern. Therefore, an anti-reflection film is formed
between an etch target film and a resist pattern.
[0003] An anti-reflection film may be formed from an organic
compound or an inorganic compound, but an anti-reflection film of
an organic compound is frequently used because it can be formed by
spin coating by using the same apparatus as that used for forming a
resist film.
[0004] A conventional pattern formation method described in, for
example, Japanese Laid-Open Patent Publication Nos. 8-153704 and
2000-77386 will now be described with reference to FIGS. 3A through
3C and 4A through 4C.
[0005] First, an anti-reflection film 2 of an organic compound is
formed on a semiconductor substrate 1 as shown in FIG. 3A, and a
resist film 3 with a thickness of 0.4 .mu.m is formed on the
anti-reflection film 2 as shown in FIG. 3B.
[0006] Next, the resist film 3 is irradiated with ArF excimer laser
5 through a photomask 4 for pattern exposure as shown in FIG. 3C,
and the resultant semiconductor substrate 1 is subjected to
post-exposure bake (PEB) carried out at, for example, 105 for 90
seconds as shown in FIG. 4A.
[0007] Then, the resist film 3 is developed with an alkaline
developer after the PEB, thereby forming a line and space resist
pattern 3A of 0.15 .mu.m as shown in FIG. 4B.
[0008] Subsequently, the anti-reflection film 2 is dry etched by
using the resist pattern 3A as a mask, thereby forming an
anti-reflection film pattern 2A from the anti-reflection film 2 as
shown in FIG. 4C.
[0009] Since exposing light recently has a shorter wavelength,
there arises necessity for increasing the anti-reflection function
of the anti-reflection film 2, and therefore, it is recently
necessary to form the anti-reflection film 2 in a large thickness
of approximately 0.1 .mu.m.
[0010] Accordingly, during the procedure for forming the
anti-reflection film pattern 2A through the dry etching of the
anti-reflection film 2 with the resist pattern 3A used as the mask,
the resist pattern 3A is largely damaged. Therefore, after
patterning the anti-reflection film 2 by the dry etching, the shape
of the resist pattern 3A is frequently degraded as shown in FIG.
4C.
[0011] When the etch target film formed on the semiconductor
substrate 1 is etched by using the resist pattern 3A in such a
degraded shape as a mask, the shape of the pattern formed from the
etch target film is also disadvantageously degraded.
SUMMARY OF THE INVENTION
[0012] In consideration of the aforementioned conventional problem,
an object of the invention is suppressing degradation in the shape
of a resist pattern caused in conducting dry etching on an
anti-reflection film of an organic compound with a large thickness
by using the resist pattern as a mask.
[0013] The pattern formation method of this invention comprises the
steps of forming an anti-reflection film of an organic compound on
a substrate; weakening the anti-reflection film by subjecting the
anti-reflection film to plasma processing; forming a resist film on
the weakened anti-reflection film; forming a resist pattern from
the resist film by subjecting the resist film to pattern exposure
and development; and patterning the anti-reflection film by dry
etching the anti-reflection film with the resist pattern used as a
mask.
[0014] In the pattern formation method of this invention, the
anti-reflection film is weakened through the plasma processing
before forming the resist film, and then, the anti-reflection film
is dry etched by using the resist pattern as a mask. Therefore, the
anti-reflection film has been weakened before being patterned.
Accordingly, the anti-reflection film can be easily dry etched,
which suppresses degradation of the shape of the resist pattern. As
a result, the etch target film can be etched by using the resist
pattern in a good shape as a mask, and hence, a pattern having a
good shape can be formed from the etch target film.
[0015] In the pattern formation method, the plasma processing is
preferably carried out by using plasma seed including oxygen or
fluorine.
[0016] Thus, the anti-reflection film can be definitely
weakened.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIGS. 1A, 1B, 1C and 1D are cross-sectional views for
showing procedures in a pattern formation method according to an
embodiment of the invention;
[0018] FIGS. 2A, 2B and 2C are cross-sectional views for showing
other procedures in the pattern formation method according to the
embodiment of the invention;
[0019] FIGS. 3A, 3B and 3C are cross-sectional views for showing
procedures in a conventional pattern formation method; and
[0020] FIGS. 4A, 4B and 4C are cross-sectional views for showing
other procedures in the conventional pattern formation method.
DETAILED DESCRIPTION OF THE INVENTION
[0021] A pattern formation method according to a preferred
embodiment of the invention will now be described with reference to
FIGS. 1A through 1D and 2A through 2C.
[0022] First, as shown in FIG. 1A, an anti-reflection film 11 (such
as AR19 manufactured by Shipley Far East Co., Ltd.) of an organic
compound having a thickness of, for example, 100 nm (0.1 .mu.m) is
formed on a semiconductor substrate 10.
[0023] Next, as shown in FIG. 1B, the anti-reflection film 11 is
irradiated with plasma 12 of a gas including oxygen or fluorine.
Thus, the anti-reflection film 11 is weakened because its density
is lowered.
[0024] The plasma processing may be carried out under any of the
following two conditions:
[0025] In the first condition, the anti-reflection film 11 is
irradiated with the plasma 12 including plasma seed of oxygen for
approximately 5 seconds in a vacuum chamber kept at a degree of
vacuum of 1.33 Pa with an oxygen gas introduced into the vacuum
chamber at a volume flow rate per minute of 15 ml in a normal
condition under application of high frequency power of 10 W. Thus,
the anti-reflection film 11 is reduced in its thickness by
approximately 8.5 nm and can be definitely weakened.
[0026] In the second condition, the anti-reflection film 11 is
irradiated with the plasma 12 including plasma seed of fluorine for
approximately 15 seconds in a vacuum chamber kept at a degree of
vacuum of 1.33 Pa with a CHF.sub.3 gas introduced into the vacuum
chamber at a volume flow rate per minute of 20 ml in a normal
condition under application of high frequency power of 50 W. Thus,
the anti-reflection film 11 is reduced in its thickness by
approximately 6.5 nm and can be definitely weakened.
[0027] Next, as shown in FIG. 1C, a resist film 13 (such as PAR-101
manufactured by Sumitomo Chemical Co., Ltd.) with a thickness of
0.4 .mu.m is formed on the anti-reflection film 11 having been
weakened by the plasma processing.
[0028] Then, as shown in FIG. 1D, the resist film 13 is irradiated
with ArF excimer laser 15 at numerical aperture (NA) of 0.60
through a photomask 14 for pattern exposure. Thereafter, as shown
in FIG. 2A, the resultant semiconductor substrate 10 is subjected
to post-exposure bake (PEB) carried out at, for example, 105 for 90
seconds.
[0029] Subsequently, as shown in FIG. 2B, the resist film 13 is
developed with an alkaline developer after the PEB, thereby forming
a line and space resist pattern 13A of 0.15 .mu.m.
[0030] Next, as shown in FIG. 2C, the weakened anti-reflection film
11 is dry etched by using the resist pattern 13A as a mask, thereby
forming an anti-reflection film pattern 11A from the
anti-reflection film 11.
[0031] Since the anti-reflection film 11 having been weakened by
the plasma processing is thus dry etched by using the resist
pattern 13A as a mask, the anti-reflection film 11 can be easily
dry etched into the pattern although it is made from an organic
compound similarly to the resist pattern 13A and has a large
thickness. Therefore, the etch target film formed on the
semiconductor substrate 10 can be etched by using the resist
pattern 13A in a good shape as a mask, resulting in forming the
pattern in a good pattern shape from the etch target film.
* * * * *