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
1999-10-15
2001-04-03
Hamilton, Cynthia (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
C430S905000, C430S910000, C430S914000, C430S919000, C430S920000, C430S921000, C430S925000, C522S050000, C522S075000, C522S078000, C522S079000, C522S152000, C522S154000, C525S328800, C526S260000, C526S301000
Reexamination Certificate
active
06210859
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a copolymer for the manufacture of chemical amplified photoresist and a positive photoresist composition containing the copolymer and more particularly, to the chemical photoresist composition which can provide several advantages: a) ultrafine patterns can be formed irrespective of any substrate, b) a higher alkali-soluble contrast can be ensured before and after exposure, c) a larger scope of exposure can be obtained, and d) a variety of excellent physical properties such as sensitivity, resolution, heat-resistance and stability after exposure. In particular, the chemical amplified positive photoresist composition of this invention can be used as ultrafine patterns-forming material for ultra-LSI which can be sensitive to UV light, far ultraviolet ray, excimer laser, X-ray and electron beam.
2. Description of the Related Art
The recent semiconductor technology has been briskly in favor of more highly integrated chip and in parallel with this trend, ultrafine patterns having less than quarter-micron are required in the photolithography patterning designed to prepare an ultra-LSI. In this respect, since the exposure wavelength becomes more short in the conventional g-ray or i-ray, the research and development project for far ultraviolet ray, KrF excimer laser, X-ray and electron beam lithograph has drawn keen attention in the related field.
A photoresist used in the conventional g-ray or i-ray employs some Novolac-quinonediazide compounds. Since such photoresist applied to the wavelength of far ultraviolet ray or KrF excimer laser absorbs a lot of light, intensive researches have focused on a chemical amplified photoresist using polyhydroxystyrene derivatives which absorb less light than these Novolac-quinonediazide compounds.
The major principle of such chemical amplified photoresist composition is that the resist layer is exposed in patterns by chemical ray, some acid generator contained in the photoresist composition releases an acid which in turn triggers an catalytically active deprotection with a resin composition, thus changing the solubility to a developer solution.
In particular, since the chemical amplified photoresist composition may demonstrate an excellent catalytic activity on resin composition in the presence of a small amount of acid generated from an acid generator, its higher resolution in patterns and better sensibility on chemical ray may be ensured.
The examples of such chemical amplified photoresist material include poly(p-t-butoxycarbonyloxystyrene/p-hydroxystyrene; U.S. Pat. No. 4,491,628), poly(p-t-butoxystyrene/p-hydroxystyrene; U.S. Pat. No. 5,350,660) and poly(p-1-ethoxyethoxystyrene/p-hydroxystyrene, Japanese Patent No. A-5-249682).
However, if some protecting groups of base resin in the photoresist material are tert-butyl group or tert-butoxycarbonyl group, they are decomposed in strong acid which in turn becomes inactivated via reaction with basic compounds in the air. The resist material is liable to form a T-top, while having different patterns according to the types of substrate. Meantime, in case of some base resins having protective groups which are decomposed in weak acids such as acetal group or ketal group, their basic compounds are less affected in the air but the formation of patterns will be extremely narrowed due to time-relapse delay from exposure to radiation to thermal treatment (PEB), while being unsuitable for higher resolution.
SUMMARY OF THE INVENTION
To cope with some drawbacks of base resins used for the conventional chemical amplified photoresist composition, therefore, an object of this invention is to provide a novel copolymer for the manufacture of chemical amplified photoresist which can provide several advantages: a) a larger scope of exposure can be obtained, b) a variety of excellent physical properties such as sensitivity, resolution, heat-resistance and stability after exposure, and c) ultrafine patterns can be formed irrespective of any substrate.
Further object of this invention is to provide a chemical amplified positive photoresist composition using the copolymer with the aforementioned characteristics.
To achieve the above objective, the copolymer for the manufacture of chemical amplified photoresist of this invention is characterized by a copolymer represented by the following formula 1.
Wherein, R
1
, R
2
, R
3
and R
4
are independently a hydrogen atom or a lower alkyl group;
R
5
, R
6
, R
7
and R
8
are a hydrogen atom, an alkyl group of C1-8, an alkoxy group, an alkoxycarbonyl group or a halogen atom;
h and i are independently an integer of 0-8; k, l, m and n represent an integer of element units provided that 0.3<k/(k+l+m+n)<0.9, 0≦l/(k+l+m+n)<0.6, 0≦m/(k+l+m+n)<0.06, and 0.01<n/(k+l+m+n)<0.3, including k+l+m+n=1. l and m may not become simultaneously zero, or are not simultaneously zero.
R
9
is a compound represented by the following formula 2:
Wherein, R
10
and R
11
are independently a hydrogen atom, or an alkyl group of C1~6 with linear or branched chain;
R
12
is an alkyl group of C1~10 with linear, branched chain or cyclic form and hence, the detailed examples of alkyl group in linear or branched chain or cyclic form include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, while a cyclic alkyl croup is cyclohyexyl group.
The detailed examples of acid-labile group represented by the above formula 2 include methoxyethyl group, ethoxyethyl group, n-butoxyethyl group or methoxypropyl group.
Am is —NR
13
R
14
(wherein, R
13
and R
14
are independently a hydrogen atom, an alkyl group of C1~8, an aryl group or a phenyl group), cyclic bivalent amines and a cyclic bivalent amines containing oxygen or sulfur atom.
Further, the chemical amplified positive photoresist composition of this invention is characterized by being prepared from a copolymer represented by the formula 1, acid generator and additive which are dissolved in an appropriate solvent.
DETAILED DESCRIPTION OF THE INVENTION
This invention is explained in more detail as set forth hereunder.
According to this invention, the preferred examples of base resin represented by the formula 1 are as follows:
(A) a quadrapolymer containing poly(hydroxystyrene/alkoxyalkoxystyrene/t-butylcarbonylalkoxystyrene/morpholinyl carbonylalkoxystyrene); k, l, m and n represent independently an integer of element units provided that 0.3<k/(k+l+m+n)<0.9, 0≦l/(k+l+m+n)<0.6, 0≦m/(k+l+m+n)<0.06, and 0.01<n/(k+l+m+n)<0.3;
(B) a terpolymer containing poly(hydroxystyrene/alkoxyalkoxystyrene/morpholinylcarbonylalkoxystyrene); k, l, m and n represent independently an integer of element units provided that 0.3<k/(k+l+m+n)<0.9, 0≦l/(k+l+m+n)<0.6, m=0, and 0.01<n/(k+l+m+n)<0.3;
(C) a terpolymer containing poly)(hydroxystyrene/t-butylcarbonylalkoxystyrene/morpholinylcarbonylalkoxystyrene);k, l, m and n represent independently an integer of element units provided that 0.3<k/(k+l+m+n)<0.9,l=0,0<m/(k+l+m+n)<0.6, and 0.01<n/(k+l+m+n)<0.3.
Among the three resins, one resin may be used as a base resin in the photoresist and if deemed necessary, two more resins may be employed.
Each component from the copolymer represented by the formula 1 has the following characteristics:
Hydroxy group serves to enhance the adhesiveness and heat-resisting property and sensitives; t-butoxycarbonylmethoxy group is converted to carboxylic acid or hydroxy group due to deprotection caused by the activity of acid when exposed to radiation; Ethoxyethoxy group is converted to hydroxy group deprotection caused by the activity of acid when exposed to radiation which results in enhancing the dissolution rate, thus ensuring a higher resolution;
Ethoxye
Jeon Hyun Pyo
Kim Seong Ju
Lee Jong Bum
Park Joo Hyeon
Birch & Stewart Kolasch & Birch, LLP
Hamilton Cynthia
Korea Kumho Petrochemical Co. Ltd.
Lee Sin J.
LandOfFree
Copolymer for the manufacture of chemical amplified... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Copolymer for the manufacture of chemical amplified..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Copolymer for the manufacture of chemical amplified... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2435753