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
2001-08-06
2002-12-10
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
C430S910000, C430S914000, C430S921000
Reexamination Certificate
active
06492091
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive photosensitive composition for use in the production process of a semiconductor such as IC, in the production of a circuit board such as liquid crystal and thermal head, and in other photofabrication processes.
BACKGROUND OF THE INVENTION
When a conventional resist comprising a novolak resin and a naphthoquinonediazide compound is used for the pattern formation by photolithography with a deep ultraviolet ray or excimer laser beam, the novolak resin and naphthoquinonediazide compound exhibit strong absorption in the deep ultraviolet region and the light scarcely reaches the bottom of resist, as a result, the resist has low sensitivity and only a tapered pattern can be obtained.
One of the techniques for solving this problem is the use of chemical amplification-type resist composition described in U.S. Pat. No. 4,491,628 and European Patent 249,139. The chemical amplification-type positive resist composition is a pattern formation material: an acid is generated in an area irradiated with radiation such as a deep ultraviolet ray and owing to a reaction using the acid as a catalyst, solubility in a developing solution is differentiated between the area irradiated with the radiation and the non-irradiated area, thereby forming a pattern on a substrate.
Examples of the chemical amplification-type resist composition include combinations of a compound capable of generating an acid by photolysis with an acetal or O,N-acetal compound (as described in JP-A-48-89003 (the term “JP-A” as used herein means an“unexamined published Japanese patent application”), with an ortho ester or amide acetal compound (as described in JP-A-51-120714), with a polymer having an acetal or ketal group on the main chain thereof (as described in JP-A-53-133429), with an enol ether compound (as described in JP-A-55-12995), with an N-acyliminocarbonic acid compound (as described in JP-A-55-126236), with a polymer having an ortho ester group on the main chain (as described in JP-A-56-17345), with a tertiary alkyl ester compound (as described in JP-A-60-3625), with a silyl ester compound (as described in JP-A-60-10247) or with a silyl ether compound (as described in JP-A-60-37549 and JP-A-60-121446). These combinations in principle have a quantum yield exceeding 1 and therefore exhibit high photosensitivity.
A system which decomposes by heating in the presence of an acid and becomes alkali-soluble is also known and examples thereof include combinations of a compound capable of generating an acid upon exposure with an ester having a tertiary or secondary carbon atom (e.g., tert-butyl or 2-cyclohexenyl) or carbonic acid ester compound as described, for example, in JP-A-59-45439, JP-A-60-3625, JP-A-62-229242, JP-A-63-27829, JP-A-63-36240, JP-A-63-250642, JP-A-5-181279
, Polym. Eng. Sce
., Vol. 23, page 1012 (1983),
ACS. Sym
., Vol. 242, page 11 (1984),
Semiconductor World
, November, 1987, page 91
, Macromolecules
, Vol. 21, page 1475 (1988), and
SPIE
, Vol. 920, page 42 (1988), with an acetal compound as described, for example, in JP-A-4-219757, JP-A-5-249682 and JP-A-6-65332, or with a tert-butyl ether compound as described, for example, in JP-A-4-211258 and JP-A-6-65333.
Such systems use as the main component a resin having a basic skeleton of poly(hydroxystyrene) which has a small absorption in the region of wave length: 248 nm. When a KrF excimer laser is employed as a light source for exposure, they exhibit high sensitivity and high resolution and are capable of forming a good pattern. Thus, they are good systems as compared with conventional naphthoquinonediazide
ovolak resin systems.
However, when the light source has a still shorter wavelength, for example, when the light source for exposure used is an ArF excimer laser (193 nm), the above-described chemical amplification type resist systems are yet deficient because the compound having an aromatic group substantially has a large absorption in the region of wave length: 193 nm. As a polymer having a small absorption in the 193 nm region, the use of poly(meth)acrylate is described in
J. Vac. Sci. Technol
., B9, 3357 (1991). However, this polymer has a problem in that the resistance against dry etching which is commonly performed in the production process of semiconductors is low as compared with conventional phenol resins having aromatic groups.
In
Proc. of SPIE
, 1672, 66 (1922), it is reported that polymers having alicyclic hydrocarbon groups exhibit the dry etching resistance on the same level as that of the compounds having aromatic groups and at the same time, have small absorption in the 193 nm region. The use of these polymers has been aggressively investigated in recent years. Specific examples of such polymers include the polymers described, for example, in JP-A-4-39665, JP-A-5-80515, JP-A-5-265212, JP-A-5-297591, JP-A-5-346668, JP-A-6-289615, JP-A-6-324494, JP-A-7-49568, JP-A-7-185046, JP-A-7-191463, JP-A-7-199467, JP-A-7-234511 and JP-A-7-252324.
Further, the use of a photo-acid generator together with a base which is decomposable to a neutral compound upon irradiation of radiation is described in JP-A-9-43837. Also, the use of a compound having a boiling point of not less than 150° C. which generates a carboxylic acid together with a compound which generates an acid other than a carboxylic acid is described in JP-A-11-125907.
However, these techniques still have a problem to be dissolved in p itch dependency. Since various patterns are included in devices according to recent tendency, various characteristics are demanded for resists. One of such characteristics is the pitch dependency. In a device there are a portion wherein lines are closely present, a portion of a pattern having a broader space compared with line and a portion of an isolated line. Therefore, to resolve various line patterns with good reproducibility is important. However, it is not necessarily easy to well reproduce various lines due to optical factors and a method for resolving such a problem by selecting a resist is uncertain at present.
Moreover, further improvement is strongly desired as to exposure margin. The exposure margin used herein means a phenomenon of changing linewidth of pattern obtained as the change of exposure amount.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to solve the above-described problems of technique for improving essential performance of microphotofabrication using a deep ultraviolet ray, particularly an ArF excimer laser beam.
Another object of the present invention is to provide a positive photosensitive composition which is excellent in the pitch dependency and exposure margin.
Other objects of the present invention will become apparent from the following description.
The objects of the present invention are accomplished by the following positive photosensitive compositions.
(1) A positive photosensitive composition comprising:
(A) a compound generating an acid upon irradiation with one of an actinic ray and radiation;
(B) a resin containing a monocyclic or polycyclic alicyclic hydrocarbon structure and increasing the solubility to an alkali developer by the action of an acid; and
(C) an onium salt of carboxylic acid.
(2) The positive photosensitive composition as described in the item (1), which further comprises (D) a dissolution-inhibiting compound: having a molecular weight of 3,000 or less; having a group capable of being decomposed by an acid; and increasing the solubility to an alkali developer by the action of an acid.
(3) The positive photosensitive composition as described in the item (1), wherein the resin (B) further contains a lactone structure.
(4) The positive photosensitive composition as described in the item (1), wherein the resin (B) further contains a repeating unit represented by formula (IV′):
wherein R
1a
represents a hydrogen atom or a methyl group; W
1
represents a single bond, an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group or a combination thereof; R
a1
, R
b1
, R
c1
, R
Aoai Toshiaki
Kodama Kunihiko
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