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
1999-12-02
2002-12-03
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
C430S270100, C430S288100, C430S914000
Reexamination Certificate
active
06489080
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive electron beam or X-ray resist composition. More particularly, the present invention relates to a positive electron beam or X-ray resist composition which is excellent in pattern profile obtained by the exposure with electron beams or X-ray, high sensitivity, excellent in resolution, and is excellent in PCD stability and PED stability with the lapse of time. PCD (Post Coating Delay) stability used herein means the film stability in the case when the resist composition is coated on a silicone wafer and allowed to stand in an electron beam irradiation apparatus under high vacuum condition, and PED (Post Exposure Delay) stability means the film stability in the case when the resist composition is allowed to stand in an electron beam irradiation apparatus under high vacuum condition during the period after electron beam irradiation and before heating process.
BACKGROUND OF THE INVENTION
Since resists of an i-line resist, a KrF excimer laser resist, an ArF excimer laser resist, etc., have the absorption in the exposure wavelength, the exposure amount at the bottom becomes less than the amount at the exposed surface, and a positive resist generally takes the shape of a pattern profile which is called a taper configuration.
However, in the case of an electron beam resist, the incident electron has electric charge and therefore interacts with the atomic nucleus and the electron of the substances constituting the resist. For this reason, scattering of an electron is bound to occur during the incidence of an electron beam to a resist film (scattering of an electron is described in Thompson, Willson and Bowden,
Introduction to Microlithography
, ACS Symposium Series 219, pp. 47 to 63). As a result, the exposure amount at the bottom of the exposed area becomes larger than the amount at the surface of the resist film, and a positive resist takes the shape of a pattern profile which is called a reverse taper configuration. Even a beam diameter is diaphragmed at exposure for resolving a fine pattern, the exposed area widens due to this scattering, as a result, resolution deteriorates.
Further, there has been a problem in the case of an electron beam resist that the resist is susceptible to the basic contaminants in the air or high vacuum condition in an electron beam irradiation apparatus (film drying), as a result, the surface becomes hardly soluble, and a T-top surface is formed (the surface becomes a T-shaped canopy top) in the case of a line pattern, and in the case of a contact hole pattern the surface takes the configuration of a capping (a canopy top is formed on the surface of the contact hole). As additional problems, the film stability in an electron beam irradiation apparatus under high vacuum condition (PCD and PED) is deteriorated with the lapse of time, and the dimension of a pattern fluctuates.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a positive electron beam or X-ray resist composition which is high sensitivity, has high resolution, can provide an excellent rectangular pattern profile, and is excellent in PCD stability and PED stability.
Another object of the present invention is to provide a positive electron beam or X-ray resist composition excellent in coating properties (in-plane uniformity).
The above objects of the present invention have been attained by the following.
(1) A positive electron beam or X-ray resist composition which contains (a) a compound which generates an acid by the irradiation with radiation, and (b) a compound having a cationic polymerizable function.
(2) The positive electron beam or X-ray resist composition as described in the above item (1), wherein (b) the compound having a cationic polymerizable function is at least a compound selected from the group consisting of a vinyl compound, a cycloalkane compound, a cyclic ether compound, a lactone compound and an aldehyde compound.
(3) The positive electron beam or X-ray resist composition as described in the above item (1) or (2), wherein (b) the compound having a cationic polymerizable function is a compound represented by formula (A):
wherein R
a
, R
b
and R
c
, which may be the same or different, each represents a hydrogen atom, or an alkyl or aryl group which may have a substituent, and any two of R
a
, R
b
and R
c
may be bonded to each other to form a saturated or olefinic unsaturated ring; and R
d
represents an alkyl group or a substituted alkyl group.
(4) The positive electron beam or X-ray resist composition as described in the above item (1), (2) or (3), wherein (a) the compound which generates an acid by the irradiation with radiation contains at least one compound represented by the following formula (I), (II) or (III):
wherein R
1
to R
37
, which may be 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 aryl group, and two or more of R
1
to R
15
, R
16
to R
27
, and R
28
to R
37
may be bonded to form a ring containing one or two or more selected from a single bond, a carbon atom, an oxygen atom, a sulfur atom and a nitrogen atom; X
−
represents an anion of benzenesulfonic acid, naphthalenesulfonic acid, or anthracenesulfonic acid having 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.
(5) The positive electron beam or X-ray resist composition as described in the above item (1), (2), (3) or (4), which contains at least either one of (c) a resin having a group decomposable with an acid and being capable of increasing solubility in an alkali developing solution by the action of an acid, or (d) a low molecular weight dissolution inhibitive compound having a molecular weight of 3,000 or less which has a group decomposable with an acid and is capable of increasing solubility in an alkali developing solution by the action of an acid.
(6) The positive electron beam or X-ray resist composition as described in the above item (1), (2) or (3), wherein (a) the compound which generates an acid by the irradiation with radiation contains at least one compound represented by formula (I), (II) or (III) described in the above item (4), and the positive electron beam or X-ray resist composition contains at least either one of (c) a resin having a group decomposable with an acid and being capable of increasing the solubility in an alkali developing solution by the action of an acid, or (d) a low molecular weight dissolution inhibitive compound having a molecular weight of 3,000 or less which has a group decomposable with an acid and is capable of increasing the solubility in an alkali developing solution by the action of an acid.
DETAILED DESCRIPTION OF THE INVENTION
As described above, in an electron beam resist composition, the incidence of an electron beam to a chemically amplified resist film causes scattering of an electron. The exposed area at the bottom becomes larger than the exposed area at the resist film surface due to the scattering of an electron (front scattering and rear scattering). As a result, the resist has a reverse taper configuration or deteriorated resolution. In a chemically amplified resist, an acid is generated at
Fujimori Toru
Kodama Kunihiko
Shirakawa Koji
Tan Shiro
Uenishi Kazuya
Ashton Rosemary
Fuji Photo Film Co. , Ltd.
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