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
2000-09-27
2002-06-25
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
C430S921000
Reexamination Certificate
active
06410204
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive photoresist composition which is used for the manufacture of semiconductors such as IC and the like, the manufacture of circuit boards for liquid crystals and thermal heads, and other photofabrication processes. More specifically, the present invention relates to a positive photoresist composition which is suitably used when actinic rays having a wavelength of 220 nm or less or radiation are used as exposure light sources.
BACKGROUND OF THE INVENTION
As positive photoresist compositions, chemically amplified resist compositions are disclosed in U.S. Pat. No. 4,491,628 and EP 249139. Chemically amplified positive resist compositions are pattern-forming materials for forming patterns on a substrate by generating an acid on an exposed area by irradiation with actinic rays or radiation and, by the reaction with the acid as a catalyst, transforming the solubilities in a developing solution of an irradiated area and a non-irradiated area with the active radiation.
As such examples, the combination of compounds which generate an acid by photolysis with acetal or O,N-acetal compounds (e.g., JP-A-48-89003 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)), with ortho esters or an anide acetal compounds (e.g., JP-A-51-120714), with polymers having an acetal or ketal group at the main chain (e.g., JP-A-53-133429), with enol ether compounds (e.g., JP-A-55-12995), with N-acyliminocarbonic acid compounds (e.g., JP-A-55-126236), with polymers having an ortho ester group at the main chain (e.g., JP-A-56-17345), with tertiary alkyl ester compounds (e.g., JP-A-60-3625), with silyl ester compounds (e.g., JP-A-60-10247), and with silyl ether compounds (e.g., JP-A-60-37549 and JP-A-60-121446) can be exemplified. These combinations show high photosensitivity as quantum yields thereof exceed 1 in principle.
Similarly, as systems which are decomposed by heating in the presence of an acid and alkali-solubilized, e.g., the combination of compounds which generate an acid by exposure (e.g., those disclosed 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, p. 1012 (1983),
ACS. Sym.,
Vol. 242, p. 11 (1984),
Semiconductor World,
p. 91 (November, 1987),
Macromolecules,
Vol. 21, p. 1475 (1988), and
SPIE,
Vol. 920, p. 42 (1988)) with esters or carbonic ester compounds of tertiary or secondary carbons (e.g., t-butyl, 2-cyclohexenyl), with acetal compounds disclosed in JP-A-4-21975, JP-A-5-249682 and JP-A-6-65332, and with t-butyl ether compounds disclosed in JP-A-4-211258 and JP-A-6-65333 can be exemplified.
On the other hand, as photo acid generators, compounds which generate a camphorsulfonic acid and a substituted benzenesulfonic acid having low diffusibility are now under examination. Further,there is a problem that the compound having high diffusibility (e.g., triphenylsulfonium trifluoromethanesulfonic acid) lowers the resolution.
However, there arises another problem that if the compound generating an acid having low diffusibility is used, the resolution is comparatively high but sensitivity and a pattern-profile are inferior.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a positive photoresist composition which is suitably used when an exposure light source having a wavelength of 220 nm or less is used, i.e., to provide a positive photoresist composition which is capable of obtaining a rectangular pattern profile and markedly excellent in sensitivity and resolution.
The above object of the present invention has been attained by the following means.
(1) A positive photoresist composition comprising
(A) a compound which generates a sulfonic acid having naphthalene structure by the irradiation with actinic rays of a wavelength of 220 nm or less or radiation, and
(B) a resin whose solubility in an alkali developing solution increases by the action of an acid.
(2) The positive photoresist composition as described in the above item (1), wherein the compound (A) is a compound represented by the following formula (I):
wherein A represents a sulfonium cation or an iodonium cation; R
1
, R
2
, R
3
and R
4
, which may be the same or different, each represents a hydrogen atom, a hydroxyl group, a halogen atom, a sulfonyl group, an alkyl group, an alkoxyl group, an alkoxycarbonyl group, or an acyloxy group, at least one of R
1
, R
2
, R
3
and R
4
may be a group bonded to other sulfonic acid residual group via a linking group, and arbitrary two of R
1
, R
2
, R
3
and R
4
may be bonded to each other to form a ring by containing one or more bonding atomic group(s) selected from the group consisting of an alkylene group, —O—, —C(═O)—O—, —S—, and —CO—O—CO—; m, n and 1 each represents an integer of 1, 2 or 3, provided that m×n=1×(the valency of cation A).
(3) The positive photoresist composition as described in the above item (1) or (2), wherein the resin (B) contains monocyclic or polycyclic alicyclic hydrocarbon structure.
(4) The positive photoresist composition as described in the above item (1), (2) or (3), wherein the resin (B) contains lactone structure.
(5) The positive photoresist composition as described in the above item (1), (2), (3) or (4), which further contains (C) a basic compound.
(6) The positive photoresist composition as described in any of the above items (1) to (5), which further contains (D) a fluorine-based and/or a silicon-based surfactant. (7) The positive photoresist composition as described in any of the above items (1) to (6), which further contains (E) a low molecular weight compound having a molecular weight of 3,000 or less whose solubility in an alkali developing solution increases by the action of an acid.
A photosensitive composition is required to be excellent in limiting resolution. For increasing limiting resolution, it is important not to disturb an exposed latent image at the time of exposure. A photo acid generator contained in a photosensitive composition generates an acid by a decomposition reaction caused by exposure. When the acid generated by decomposition has high diffusibility, the exposed latent image is disturbed. Accordingly, it is thought to be important that the diffusibility of the acid generated by decomposition should be low. From that point of view, a sulfonic acid compound, in particular, a bulky sulfonic acid compound has attracted public attention. In place of triphenylsulfonium trifluoro-methanesulfonates, which have so far been used in general, photo acid generators which generate a camphorsulfonic acid and a (substituted) benzenesulfonic acid by a photochemical reaction have been developed.
A camphorsulfonic acid has transparency to light of wavelength of 193 nm. This is a preferred characteristic but the generated acid is comparatively weak. Therefore, the deprotecting reaction using the acid as a catalyst is delayed, as a result, the sensitivity lowers.
Further, benzenesulfonic acid moieties which do not participate in the photolysis of photo acid generators which generate benzenesulfonic acids have a large absorbing power to light of wavelength of 193 nm. This light-absorbing power hinders the photolysis reaction and lowers the sensitivity. Further, there is a problem that a profile becomes tapered due to this light-absorbing power.
The present inventors have solved the above problem clearly by using a photo acid generator having specific structure as a photosensitive composition.
DETAILED DESCRIPTION OF THE INVENTION
Compounds which Generate Sulfonic Acid having Naphthalene Structure
In the present invention, a compound which generates a sulfonic acid having naphthalene structure by the irradiation with actinic rays of a wavelength of 220 nm or less or radiation is contained as one constituent. Actinic rays of a wavelength of 220 nm or less or radiation can be obtained from, e.g., an ArF eximer laser (193 nm), an F
2
eximer laser (157 nm), an X-ray, an electron beam, etc.
As the com
Aoai Toshiaki
Kodama Kunihiko
Sato Kenichiro
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