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
2003-03-19
2004-07-13
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
C430S326000, C430S905000, C430S909000, C430S914000
Reexamination Certificate
active
06762007
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a resist composition suitable for lithography and the like acting by high-energy radiation such as far ultraviolet ray (including excimer laser and the like), electron beam, X ray or radiation light.
2. Prior Art
Recently, formation of sub-micron patterns is required because of enhanced integration of integrated circuits. Particularly, lithography using excimer laser from krypton fluoride (KrF) or argon fluoride (ArF) is drawing attention since it enables production of 64 M to 1 G DRAM. As the resist suitable for such excimer laser lithography process, so-called chemical amplification type resist utilizing chemical amplification effect is being adopted. With the chemical amplification type resist, acids generated from an acid generator in parts irradiated with radioactive ray are diffused by the post exposure bake (hereinafter, sometimes abbreviated as PEB), and the solubility of the irradiated parts in an alkali developer is changed by a reaction using the acid as a catalyst, and thereby positive or negative patterns are obtained.
The chemical amplification type positive resist comprises resin which itself is insoluble or poorly soluble in an alkali aqueous solution but becomes soluble in an alkali aqueous solution by the action of an acid, and an acid generator. In general, as the resin which itself is insoluble or poorly soluble in an alkali aqueous solution but becomes soluble in an alkali aqueous solution by the action of an acid, poly(p-hydroxystyrene) protected with acetal group is used. However, when the ratio of the acetal protective group to the resin is increased for enhancing the resolution of the resist, the resolution of dense patterns (dense resolution) increases, while the resolution of isolated patterns (isolated resolution) deteriorates, and when the ratio of the acetal protective group to the resin is decreased for enhancing the isolated resolution, the dense resolution deteriorates, and solubility in an alkali developer increases and membrane remaining ratio decreases, and the like. Therefore, it has been industrially extremely difficult to increase basic abilities such as resolution, particularly isolated resolution and the like by controlling the ratio of the above-mentioned acetal protective group, without lowering membrane remaining ratio.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a chemical amplification type positive resist composition which can enhance basic abilities such as sensitivity, resolution, particularly isolated resolution and the like, without lowering membrane remaining ratio.
(0005)
The present inventors have found that the object of the present invention is accomplished by using specific resins in combination as the resin components of a chemical amplification type positive resist composition.
(0006)
Namely, the present invention relates to the followings.
<1> A chemical amplification type positive resist composition comprising (A) resin having a phenol skeleton wherein the phenol skeleton has protective group which can be dissociated by the action of an acid, the phenol skeleton itself is insoluble or poorly soluble in an alkali aqueous solution and the phenol skeleton becomes soluble in an alkali aqueous solution after dissociation of the protective group (hereinafter referred to “Component (A)”), (B) resin obtained by protecting a part of hydroxyl group in poly(p-hydroxystyrene) with pivaloyl group (hereinafter referred to “Component (B)”) and (C) an acid generator (hereinafter referred to “Component (C)”).
<2> The chemical amplification type positive resist composition according to <1>, wherein the content of Component (A), Component (B) and Component (C) is 50 to 89.9%, 10 to 50% and 0.1 to 20% by weight respectively, based on the total solid content in the resist composition.
<3> The chemical amplification type positive resist composition according to <1> or <2>, wherein the protective group in Component (A) is acetal group.
<4> The chemical amplification type positive resist composition according to <1> or <2>, wherein the protective group in Component (A) is 1-ethoxyethyl group.
<5> The chemical amplification type positive resist composition according to any one of <1> to <4>, which further comprises an acid proliferating agent in addition to Component (A), Component (B) and Component (C).
<6> The chemical amplification type positive resist composition according to <5> wherein the content of the acid proliferating agent is 0.01 to 20% by weight, based on the total solid content in the resist composition.
<7> The chemical amplification type positive resist composition according to any one of <1> to <6>, which further comprises a nitrogen-containing basic organic compound in addition to Component (A), Component (B) and Component (C).
<8> The chemical amplification type positive resist composition according to <7> wherein the content of the nitrogen-containing basic organic compound is 0.01 to 10% by weight, based on the total solid content in the resist composition.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the resist composition of the present invention, one of the resin components is Component (A).
The examples of Component (A) can be those obtained by introducing protective group which can be dissociated by the action of an acid into resin having a phenol skeleton. Examples of the resin having a phenol skeleton include poly(p-hydroxystyrene).
Such groups having an ability to suppress dissolution into an alkali developer but unstable to an acid can be various known protective groups. Examples thereof include tert-butyl; groups in which quaternary carbon is bonded to oxygen atom such as tert-butoxycarbonyl, tert-butoxycarbonylmethyl, and the like; acetal type groups such as tetrahydro-2-pyranyl, tetrahydro-2-furyl, 1-ethoxyethyl, 1-(2-methylpropoxy)ethyl, 1-(2-methoxyethoxy)ethyl, 1-(2-acetoxyethoxy)ethyl, 1-[2-(1-adamantyloxy)ethoxy]ethyl, 1-[2-(1-adamantanecarbonyloxy)ethoxy]ethyl, and the like; residues of non-aromatic cyclic compounds such as 3-oxocyclohexyl, 4-methyltetrahydro-2-pyron-4-yl (derived from mevalonic lactone), and the like, and these groups will be substituted for hydrogen atom of phenolic hydroxyl group. These protective groups can be introduced into alkali-soluble resin having phenolic hydroxyl group by a known protective group introduction reaction. The above-mentioned resin can be obtained also by copolymerization using unsaturated compound having such group as one monomer.
In the resist composition of the present invention, other one of the resin components is Component (B).
Specifically, Component (B) is preferably resin obtained by protecting 10 to 60 mol % of hydroxyl group in poly(p-hydroxystyrene) with pivaloyl group.
Component (C), another component of the positive resist composition, is that which is decomposed to generate an acid by allowing radioactive ray such as light and electron beam to act on the acid generator itself or a resist composition containing the acid generator. The acid generated from the acid generator acts on the above-mentioned resin, to dissociate acid-labile group present in the resin. Such acid generators include, for example, onium salt compounds, s-triazine-based organic halogen compounds, sulfone compounds, sulfonate compounds and the like.
Specific examples of the acid generators include the following compounds.
Diphenyliodonium trifluoromethanesulfonate,
4-methoxyphenylphenyliodinium hexafluoroantimonate,
4-methoxyphenylphenyliodinium trifluoromethanesulfonate,
bis(4-tert-butylphenyl)iodonium tetrafluoroborate
bis(4-tert-butylphenyl)iodonium perfluorobutanesulfonate,
bis(4-tert-butylphenyl)iodonium hexafluorophosphate,
bis(4-tert-butylphenyl)iodonium hexafluoroantimonate
bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate,
bis(4-tert-butylphenyl)iodonium camphorsulfonate,
triphenylsulfonium hexafluorophosp
Namba Katsuhiko
Ochiai Koshiro
Suetsugu Masumi
Huff Mark F.
Lee Sin J.
Sumitomo Chemical Company Limited
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