Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
2001-01-17
2004-01-06
Ashton, Rosemary (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S296000, C430S967000
Reexamination Certificate
active
06673512
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a negative-working resist composition suitably used in an ultramicrolithography process or another photofabrication process for the production of VLSIs (very large scale integration) or high capacity microchips. More particularly, the invention relates to a negative-working photo resist composition which can form highly miniaturized patterns by use of X-rays or electron beams, and especially to a negative-working resist composition which can be suitably used in miniaturization processing of semiconductor devices by use of high energy beams such as electron beams.
BACKGROUND OF THE INVENTION
Integrated circuits have been progressively increased in their integration degree, and therefore processing of ultra-micro patterns having a line width of a half micron or less has become necessary in the production of semiconductor substrates for VLSIs. For fulfilling this necessity, the wavelength of light used in an exposure apparatus employed for photolithography becomes progressively shorter, and now, far ultraviolet light and excimer laser light (such as XeCl, KrF or ArF) has been studied. Further, the formation of more micro patterns with electron beams or X-rays has been studied.
In particular, electron beams or X-rays are placed as advanced or further advanced technology of pattern formation, and the development of negative resists which can attain high sensitivity, high resolution and a rectangular profile has been desired.
Electron beam lithography is technology in which accelerated electron beams emit energy in the course of colliding with atoms constituting resist materials to cause scattering, thereby exposing the resist materials. The use of highly accelerated electron beams increases the rectilinear propagation and reduces the influence of electron scattering, which makes it possible to form rectangular patterns having high resolution. On the other hand, it increases the permeability of electron beams, resulting in lowered sensitivity. As described above, in the electron beam lithography, there is the trade-off relationship between the sensitivity and the resolution/resist shape, and it has been a problem how to allow them to be compatible with each other.
With respect to chemical amplification type negative resists, various alkali-soluble resins have hitherto been proposed. JP-A-8-152717 (the term “JP-A” as used herein means an “unexamined published Japanese patent application) discloses partially alkyl etherified polyvinylphenol, JP-A-6-67431 and JP-A-10-10733 disclose copolymers of vinylphenol and styrene, Japanese Patent No. 2505033 discloses novolak resins, and JP-A-7-311463 and JP-A-8-292559 disclose monodisperse polyvinylphenol. However, these alkali-soluble resins have not allowed the sensitivity under irradiation of electron beams or X-rays to be compatible with the resolution/resist shape.
In addition, with respect to chemical amplification type negative resists, various acid generating agents have hitherto been proposed. JP-B-8-3635 (the term “JP-B” as used herein means an “examined Japanese patent publication”) discloses organic halogen compounds, JP-A-2-150848 and JP-A-6-199770 disclose iodonium salts and sulfonium salts, JP-A-2-52348, JP-A-4-367864 and JP-A-4-367865 disclose acid generating agents containing Cl or Br, JP-A-4-210960 and JP-A-4-217249 disclose diazodisulfone and diazosulfone compounds, JP-A-4-226454 discloses triazine compounds, and JP-A-3-87746, JP-A-4-291259, JP-A-6-236024 and U.S. Pat. No. 5,344,742 disclose sulfonate compounds. However, these acid generating agents have failed to overcome the trade-off relationship between the sensitivity and the resolution/resist shape under irradiation of electron beams.
Further, as to crosslinking agents, methylolmelamine, resol resins, epoxidated novolak resins and urea resins have hitherto been used. However, these crosslinking agents are unstable to heat, so that they have a problem with regard to storage stability when used in resist solutions. Furthermore, they have failed to satisfy required characteristics of high sensitivity, high resolution and rectangular resist shape under irradiation of electron beams.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to solve the problems in respect to techniques for improving the original performance in miniaturization processing of semiconductor devices using electron beams or X-rays, and to develop chemical amplification system negative-working resist compositions for electron beams or X-rays satisfying the characteristics of sensitivity and resolution/resist shape to the use of the electron beams or the X-rays.
As a result of intensive studies, the present inventors have known that the above-mentioned various objects of the invention are attained by the use of specific alkali-soluble resins, depending on the type of radiation-sensitive composition, thus completing the invention.
That is to say, these and other objects of the invention are attained by the following:
(1) A chemical amplification system negative-working resist composition for an electron beam and/or an X-ray comprising an alkali-soluble resin having structural units represented by the following general formula (a), a compound generating an acid by irradiation of the electron beam or the X-ray, and a crosslinking agent which initiates crosslinking by the acid:
wherein R
1
represents a hydrogen atom, a halogen atom, a cyano group, or an alkyl, oxyalkyl or haloalkyl group which may have a substituent; X represents an integer of from 0 to 3; R
2
represents a hydrogen atom, or an alkyl, cycloalkyl, alkenyl, aralkyl, aryl or acyl group which may have a substituent, wherein a plurality of R
2
's are present, they maybe the same or different; R
3
represents a hydrogen atom, a halogen atom, a cyano atom, or an alkyl, cycloalkyl, alkenyl, aralkyl or aryl group which may have a substituent, wherein a plurality of R
3
's are present, they may be the same or different; two of the plurality of R
2
's, two of the plurality of R
3
's, or R
2
and R
3
may combine with each other to form a ring; A
1
represents a single bond, or a divalent alkylene, alkenylene, cycloalkylene or arylene group which may have a substituent, or —O—, —SO
2
—, —O—CO—R
5
—, —CO—O—R
6
— or —CO—N(R
7
)—R
8
—, wherein R
5
, R
6
and R
8
, which may be the same or different, each represents a single bond, or a divalent alkylene, alkenylene, cycloalkylene or arylene group which may have an ether group, an ester group, an amido group, a urethane group or a ureido group and may further have a substituent, and R
7
represents a hydrogen atom, or an alkyl, cycloalkyl, aralkyl or aryl group which may have a substituent;
(2) The negative-working resist composition described in the above (1), wherein the alkali-soluble resin is a resin containing structural units represented by the following general formula (1):
wherein R
1a
represents a hydrogen atom or a methyl group;
(3) The negative-working resist composition described in the above (1), wherein the alkali-soluble resin is a resin represented by the following general formula (2):
wherein R
1a
to R
5a
each independently represents a hydrogen atom or a methyl group; R
6a
to R
11a
each represents a hydrogen atom, an alkyl or alkoxyl group having from 1 to 4 carbon atoms, a hydroxyl group or —C(═O)O—R
14a
, wherein R
4a
represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; R
12a
represents —COOR
15a
, wherein R
15a
represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; and
0<1≦100, 0≦m,n,o,p<100
and l+m+n+o+p=100;
(4) The negative-working resist composition described in the above (1), (2) or (3), wherein the radiation-sensitive acid generating agent contains at least one of compounds represented by the following general formulas (I) to (III):
wherein R
1
to R
37
each represents a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, a halogen atom or a group indicated by —S—R
38
,
Adegawa Yutaka
Shirakawa Koji
Uenishi Kazuya
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