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
2002-10-21
2004-08-10
Huff, Mark F. (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
C430S287100, C430S325000, C430S905000, C430S906000, C430S907000, C430S914000, C430S296000, C430S942000, C430S966000, C430S967000
Reexamination Certificate
active
06773862
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a negative resist composition which is used in the production steps of lithographic printing plates and semiconductors such as IC, in the production of circuit boards of liquid crystals, thermal heads, etc., and in other fabrication steps. In particular, the negative resist composition of the invention acts by far ultraviolet rays (including excimer laser), electron beams, X-rays, or high-energy radiations such as emitted light.
BACKGROUND OF THE INVENTION
In the production process of semiconductor devices such as IC and LSI, there has hitherto been employed micro-fabrication by lithography using a photoresist composition. In recent years, with the high integration of integrated circuits, it is being demanded to form hyperfine patterns of a sub-micron region or a quarter-micron region. Following this, there is seen a tendency that the exposure wavelength becomes shorter, for example, from g-rays to i-rays and further to a KrF excimer laser light. In addition, besides the excimer laser light, development of lithography using electron beams proceeds at present. As resists suited for the excimer laser or electron beams-lithography process are mainly employed chemically amplified resists.
A chemically amplified resist composition is a material in which upon irradiation with radiations such as far ultraviolet rays and electron beams, it generates an acid in an exposed area, and reaction using this acid as a catalyst changes the solubility to a development liquid in an irradiated area with the radiations and in a non-irradiated area, thereby forming a pattern on a substrate. The chemically amplified resist has high sensitivity and resolution and has an advantage such that an image can be formed with a compound capable of generating an acid upon irradiation at a small dose of radiations (this compound will be hereinafter referred to as “photo-acid generator”).
Though the chemically amplified resist has advantages of high sensitivity and high resolution as described above, with the progress of finer patterns, line edge roughness of the pattern has become a serious problem that is never negligible.
The line edge roughness as referred to herein means a phenomenon in which a pattern of a resist and an edge at an interface with a substrate irregularly fluctuate in a vertical direction to the line direction due to characteristics of the resist, whereby when seeing from the upper side, the edge appears uneven. This unevenness is transferred by the etching step using the resist as a mask, thereby degrading the electrical properties, leading to a reduction of the yield. Especially, in hyperfine regions of 0.25 &mgr;m or less, the line edge roughness is an extremely important problem to be improved. The high sensitivity and high resolution and the good line edge roughness are in a trade-off relation, and therefore, it is very important how to make the both cope with each other.
With respect to the chemically amplified resists, there have been made various investigations from the viewpoints of acid generators, crosslinking agents, and so on. For example, JP-A-7-128855 (The term “JP-A” as used herein means an “unexamined published Japanese patent application”) discloses triazine-based photo-acid generators; JP-A-9-43837 and JP-A-11-125907 disclose carboxylic acid-generating photo-acid generators; JP-A-5-181277 and JP-A-7-146556 disclose methoxymethylmelamine crosslinking agents; and JP-A-6-83055 discloses alkoxymethyl ether-type crosslinking agents. Further, as to additives, JP-A-5-289340 discloses amino acid-type additives; and JP-A-8-110638 discloses ammonium salt-type additives.
However, in any combinations of these compounds, high sensitivity, high resolution, good pattern shape, and good line edge roughness could not be satisfied simultaneously in hyperfine regions.
SUMMARY OF THE INVENTION
Accordingly, an object of the invention is to solve the problems in performance in micro-fabrication of semiconductor elements using actinic rays or radiations, especially KrF excimer laser, electron beams or X-rays and to provide a negative chemically amplified resist that can be satisfied simultaneously with the characteristics of sensitivity, resolution, pattern shape and line edge roughness in using KrF excimer laser, electron beams or X-rays.
The present inventors made extensive and intensive investigations. As a result, it has been found that the above-described-object can be achieved by adding at least two kinds of specific crosslinking agents in a chemically amplified negative resist composition using an alkali-soluble polymer, a crosslinking agent, and a photo-acid generator, leading to accomplishment of the invention.
The invention is constituted as follows.
(1) A negative resist composition comprising:
(A) a compound which generates an acid upon irradiation with actinic rays or radiations,
(B) an alkali-soluble polymer, and
(C) a crosslinking agent which generates crosslinking with the polymer (B) by the action of an acid, wherein the crosslinking agent (C) contains at least two kinds of compounds having a different skeleton from each other, which are selected from phenol derivatives having two or more hydroxymethyl groups and/or alkoxymethyl groups on a benzene ring thereof, in which one kind of the crosslinking agent contains one or two benzene rings in the molecule thereof, and another kind of the crosslinking agent contains from 3 to 5 benzene rings in the molecule thereof.
(2) The negative resist composition as set forth in (1) above, further comprising (E) a nitrogen-containing basic compound.
(3) The negative resist composition as set forth in (1) or (2) above, wherein the polymer (B) is a polymer containing a recurring (repeating) unit represented by the following formula (b):
In the formula (b), R
1
represents a hydrogen atom, a halogen atom, a cyano group, or an optionally substituted alkyl group; R
2
represents a hydrogen atom or an optionally substituted alkyl group, cycloalkyl group, aryl group, aralkyl group or acyl group; R
3
and R
4
, which may be the same or different, each represents a hydrogen atom, a halogen atom, a cyano group, or an optionally substituted alkyl group, cycloalkyl group, alkenyl group, aralkyl group or aryl group; A represents a simple bond (single bond), an optionally substituted alkylene group, alkenylene group, cycloalkylene group or arylene group, or —O—, —SO
2
—, —O—CO—R
5
—, —CO—O—R
6
— or —CO—N(R
7
)—R
8
—; R
5
, R
6
, and R
8
, which may be the same or different, each represents a simple bond, an optionally substituted alkylene group, alkenylene group, cycloalkylene group or arylene group singly, or a divalent group formed from at least one of these groups taken together with at least one member selected from the group consisting of an ether structure, an ester structure, an amide structure, a urethane structure, and a ureido structure; R
7
represents a hydrogen atom or an optionally substituted alkyl group, cycloalkyl group, aralkyl group or aryl group; n represents an integer of from 1 to 3; and plural R
2
's, or R
2
and R
3
or R
4
, may be bound to each other to form a ring.
(4) The negative resist composition as set forth in (1) or (2) above, wherein the polymer (B) is a polymer containing at least one recurring unit represented by the following formula (b-2) or (b-3):
In the formulae (b-2) and (b-3), R
1
and A are synonymous with R
1
and A in the formula (b); R
101
to R
106
each independently represents a hydroxyl group, a carboxy group, an amino group, or an optionally substituted alkyl group, cycloalkyl group, alkoxy group, alkylcarbonyloxy group, alkylsulfonyloxy group, alkenyl group, aryl group, aralkyl group, N-alkylamino group or N-dialkylamino group; a to f each independently represents an integer of from 0 to 3; and Y represents any one of the following fused (condensed) polycyclic aromatic structures:
(5) The negative resist composition as set forth in any one of (1) to (4) above, wherein the actinic rays or radiations are any one of an excimer laser light havin
Adegawa Yutaka
Shirakawa Koji
Yasunami Shoichiro
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