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
2002-02-05
2004-04-13
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
C430S905000, C430S914000
Reexamination Certificate
active
06720128
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive chemical amplification resist composition, more specifically relates to a positive chemical amplification resist composition excellent in pattern profile obtained by exposure with electron beams or X-rays, exhibiting high sensitivity and high resolution, and excellent in process delay stability (PCD, PED and PBD) with the lapse of time.
“PCD (Post Coating Delay) stability” means the film stability in the case where a resist composition is coated on a substrate and allowed to stand inside or outside of an irradiation apparatus. “PED (Post Exposure Delay) stability” means the film stability in the case where a resist composition is allowed to stand inside or outside of an irradiation apparatus during the period of time after electron beam irradiation and before heating operation. “PBD (post bake delay) stability” means the film stability in the case where a resist composition is allowed to stand inside or outside of an irradiation apparatus during the period of time from heating operation after exposure (post exposure bake) to development.
BACKGROUND OF THE INVENTION
The degree of integration of integrated circuits has been heightened more and more, and processing of ultra-fine pattern comprising a line width of half a micrometer or less has been required in the manufacture of semiconductor substrates, such as ultra LSI. For satisfying the necessity, a chemical amplification resist is used as the resist material for lithography.
In particular, the electron beam and X-ray are positioned as the pattern-forming technique of the next generation or the next of the next generation, and the development of a positive resist composition capable of obtaining high sensitivity, high resolution and a rectangular profile has been desired.
Further, the positive chemical amplification resist is easily influenced by the basic contaminants in air, or liable to be influenced by exposure to air in and outside an irradiation apparatus (drying of a film), and the surface of the compositions becomes hardly soluble. As a result, there arises a problem that the pattern becomes a T-top shape (the surface forms T-shaped eaves) in case of a line pattern, and the surface becomes a capped shape (eaves are formed on the contact hole surface) in case of a contact hole pattern. In addition, there is another problem that the stability with the lapse of time (PCD and PED) in and outside an irradiation apparatus is deteriorated and the pattern dimension fluctuates.
Furthermore, as compared with resists for photo-lithography, such as an i-ray resist, a KrF eximer laser resist and an ArF eximer laser resist, resists for electron beam lithography and X-ray lithography are high in resolution, but low in throughput. Therefore, the development of a resist which shows high sensitivity while maintaining high resolution has been desired.
Further, there is another problem that the storage stability (PBD stability) of a positive chemical amplification resist is also deteriorated when allowed to stand during the period of time from heating operation after exposure to development.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a positive chemical amplification resist composition which is high sensitivity, high resolution and capable of providing an excellent rectangular pattern profile, and is excellent in PCD and PED stability as well.
Another object of the present invention is to provide a positive chemical amplification resist composition which is excellent in coating property (in-plane uniformity).
A further object of the present invention is to provide a positive resist composition for an electron beam or an X-ray which can obtain high sensitivity, high resolution and also PBD (post bake delay) stability.
That is, the above objects of the present invention have been accomplished by the following positive resist composition.
1. A positive chemical amplification resist composition (a first embodiment) which comprises (a) a compound capable of directly or indirectly generating a radical (A) on irradiation with an energy ray.
2. The positive chemical amplification resist composition as described in 1., which further comprises (b) a compound capable of generating an acid on irradiation with an energy ray.
3. The positive chemical amplification resist composition as described in 1., which further comprises at least one of: (e) a resin: containing an acid-decomposable group; and being capable of increasing the solubility in an alkali developer by the action of an acid; and (g) a resin insoluble in water and soluble in an alkali developer.
4. The positive chemical amplification resist composition as described in 1., which further comprises (f) a low molecular weight dissolution-inhibiting compound: having a molecular weight of 3,000 or less; containing an acid-decomposable group; and being capable of increasing the solubility in an alkali developer by the action of an acid.
5. The positive chemical amplification resist composition as described in 1., wherein the radical (A) is capable of generating an acid by a reaction with the compound (a).
6. The positive chemical amplification resist composition as described in 1., wherein the compound (a) is at least one compound selected from the group consisting of:
(1) an alkyl halide other than an alkyl fluoride, an aryl halide other than an aryl fluorine, an aralkyl halide other than an aralkyl fluorine, and an allyl halide other than an allyl fluorine,
in which a part or all of the hydrogens in the alkyl halide, the aryl halide, the aralkyl halide and the allyl halide may be substituted with a fluorine,
(2) a thiol compound, a secondary alcohol, a substituted or unsubstituted allyl alcohol, a benzyl alcohol which may be a substituent on the aromatic ring, ester and ether compounds of them, a sulfide compound, and a disulfide compound,
(3) a halogen-containing silicon compound and an alkoxy silicon compound,
(4) a straight chain, branched or cyclic acetal compound, and
(5) an N-hydroxyl compound.
7. The positive chemical amplification resist composition as described in 2., wherein the compound (b) contains at least one compound represented by formula (II) or (III):
wherein R
16
to R
37
, which are the same or different, each represents a hydrogen atom, a straight chain, branched or cyclic alkyl group, a straight chain, branched or cyclic alkoxyl group, a hydroxyl group, a halogen atom, or an —S—R
38
group; R
38
represents a straight chain, branched or cyclic alkyl group, or an aryl group, and at least two of R
16
to R
27
, and at least two of R
28
to R
37
may be bonded to form a ring containing at least one selected from a single bond, a carbon atom, an oxygen atom, a sulfur atom and a nitrogen atom; and X
−
represents an anion of a sulfonic acid.
8. The positive chemical amplification resist composition as described in 7., wherein X
−
represents an anion of an alkylsulfonic acid, a benzenesulfonic acid, a naphthalenesulfonic acid or an anthracenesulfonic acid, each of which has at least one group selected from the group consisting of:
at least one fluorine atom;
a straight chain, branched, or cyclic alkyl group substituted with at least one fluorine atom;
a straight chain, branched, or cyclic alkoxyl group substituted with at least one fluorine atom;
an acyl group substituted with at least one fluorine atom;
an acyloxy group substituted with at least one fluorine atom;
a sulfonyl group substituted with at least one fluorine atom;
a sulfonyloxy group substituted with at least one fluorine atom;
a sulfonylamino group substituted with at least one fluorine atom;
an aryl group substituted with at least one fluorine atom;
an aralkyl group substituted with at least one fluorine atom; and
an alkoxycarbonyl group substituted with at least one fluorine atom.
9. The positive chemical amplification resist composition as described in 1., which further comprises (c) an organic basic compound.
10. The positive chemical amplification resist composition as described in 1., which further
Adegawa Yutaka
Aoai Toshiaki
Nakamura Ippei
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