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
2003-03-03
2004-11-09
Le, Hoa Van (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
C430S914000, C430S945000
Reexamination Certificate
active
06815146
ABSTRACT:
The present invention relates to a novel fluorinated resist composition. More particularly, it relates to a chemical amplification type resist composition useful for fine processing employing far ultraviolet rays such as KrF or ArF excimer laser, or vacuum ultraviolet rays such as F
2
excimer laser.
In recent years, along with the progress in fine circuit patterns in the process for producing semiconductor integrated circuits, a photoresist material having high resolution and high sensitivity is desired. As the circuit patterns become fine, a short wavelength of a light source for an exposure apparatus becomes essential. In an application to lithography employing an excimer laser of 250 nm or shorter, a polyvinyl phenol type resin, an alicyclic acrylic type resin, a polynorbornene type resin or a fluororesin has, for example, been proposed, but no adequate resolution and sensitivity have been obtained.
It is an object of the present invention to provide a resist composition which is particularly excellent in transparency to far ultraviolet rays such as KrF or ArF excimer laser or vacuum ultraviolet rays such as F
2
excimer laser and dry etching properties, as a chemical amplification type resist and which gives a resist pattern excellent in sensitivity, resolution, evenness, heat resistance, etc.
The present invention is the following invention which has been made to solve the above-described problems.
A resist composition comprising the following fluoropolymer (A), an acid-generating compound (B) which generates an acid under irradiation with light and an organic solvent (C):
Fluoropolymer (A): a fluoropolymer having blocked acidic groups, which is a fluoropolymer having monomeric units formed by cyclopolymerization of a fluorinated diene of the formula (1) and monomeric units formed by polymerization of an acrylic monomer of the formula (2) and which is, when a copolymer obtained by polymerizing the fluorinated diene of the formula (1) and the acrylic monomer of the formula (2), has no blocked acidic groups, obtained by forming blocked acidic groups in the copolymer:
CF
2
═CR
1
—Q—CR
2
═CH
2
(1)
wherein each of R
1
and R
2
which are independent of each other, is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and Q is a bivalent organic group which is a blocked acidic group capable of forming an acidic group by an acid, an acidic group, or a group which can be converted to a blocked acidic group and which is other than an acidic group;
CH
2
═CR
3
—CO
2
R
4
(2)
wherein R
3
is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R
4
is a hydrogen atom, a hydrocarbon group, an organic group having an acidic group, an organic group having a blocked acidic group capable of forming an acidic group by an acid, or an organic group having a group which can be converted to a blocked acidic group and which is other than an acidic group.
It is considered that by the copolymerization of the fluorinated diene of the formula (1) (hereinafter referred to also as the fluorinated diene (1)) with the acrylic monomer of the formula (2) (hereinafter referred to also as the acrylic monomer (2)), a cyclized copolymer having the following monomeric units (a) to (c) derived from the fluorinated diene (1) will be formed. From the results of the spectroscopic analyses, etc., this cyclized copolymer is considered to be a polymer having a structure comprising monomeric units (a), monomeric units (b) or both of them, as the main monomeric units. Here, the main chain of this cyclized copolymer is meant for a carbon chain composed of carbon atoms constituting polymerizable unsaturated bonds (in the case of the fluorinated diene (1), four carbon atoms constituting the polymerizable unsaturated double bonds).
The fluoropolymer (A) in the present invention has blocked acidic groups capable of forming acidic groups by an acid (hereinafter referred to simply as blocked acidic groups). In a case where the fluorinated diene (1) and/or the acrylic monomer (2) has a blocked acidic group, the fluoropolymer (A) can be obtained by their copolymerization. In a case where the fluorinated diene (1) and the acrylic monomer (2) have no blocked acidic groups, the fluoropolymer (A) can be obtained by converting acidic groups or groups which can be converted to blocked acidic groups and which are other than acidic groups (hereinafter referred also as the precursor groups), present in the copolymer of the fluorinated diene (1) with the acrylic monomer (2), to blocked acidic groups. The acidic groups can be converted to the blocked acidic groups by reacting them with a blocking agent. The precursor groups may, for example, be blocked acidic groups other than the desired blocked acidic groups (such as those which can not easily be deblocked by an acid generated from the acid-generating compound (B)). They may be converted to the desired blocked acidic groups by converting the blocked portions directly or via acidic groups.
It is preferred that the fluoropolymer (A) in the present invention further has acidic groups, whereby the solubility of the resist material can be controlled. The blocked ratio of the fluoropolymer (A) (i.e. the ratio of blocked acidic groups to the total of the blocked acidic groups and non-blocked acidic groups) is preferably from 10 to 99 mol %, particularly preferably from 10 to 90 mol %.
In the formula (1), each of R
1
and R
2
which are independent of each other, is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R
1
is preferably a fluorine atom or a trifluoromethyl group. R
2
is preferably a hydrogen atom or a methyl group. Q is a bivalent organic group which is an organic group having a blocked acidic group, an acidic group or the precursor group.
In Q, the minimum distance between connecting bonds at its both terminals corresponds preferably to from 2 to 6 atoms, particularly preferably 2 to 4 atoms, as represented by the number of atoms (the atomic chain constituting this minimum distance will be hereinafter referred to as the main chain). The atoms constituting the main chain may be composed of carbon atoms only, or carbon atoms and other bivalent or higher valent atoms. The bivalent or higher valent atoms other than carbon atoms, may, for example, an oxygen atom, a sulfur atom and a nitrogen atom substituted by a monovalent group. An oxygen atom is particularly preferred. Such an oxygen atom or the like may be present at either one or both of the two terminals, or may be present between carbon atoms in Q.
In the main chain in Q, at least one carbon atom is present, and to a carbon atom constituting the main chain in Q, a blocked acidic group, an acidic group, a precursor group or an organic group containing a blocked acidic group, an acidic group or a precursor group, is bonded. In addition to such a specific group, hydrogen atoms or halogen atoms (particularly preferably fluorine atoms) are bonded to carbon atoms, etc. constituting the main chain, and further, an alkyl group, a fluoroalkyl group, an alkoxy group, an aryl group or other organic groups may be bonded thereto. The carbon number of such an organic group is preferably at most 6.
The acidic group may, for example, be an acidic hydroxyl group, a carboxylic group or a sulfonic group, particularly preferably an acidic hydroxyl group and a carboxylic group, most preferably an acidic hydroxyl group. The acidic hydroxyl group is a hydroxyl group showing acidity, and it may, for example, be a hydroxyl group bonded directly to the ring of an aryl group (a phenolic hydroxyl group), a hydroxyl group bonded to a carbon atom having a perfluoroalkyl group (preferably a C
1-2
perfluoroalkyl group) bonded thereto, or a hydroxyl group bonded to a tertiary carbon atom. Particularly preferred is a hydroxyl group bonded to a carbon atom having one or two perfluoroalkyl groups bonded thereto. In a case where the perfluoroalkyl group is a trifluoromethyl group, for example, a hydroxyl group in a bivalent group of the foll
Kaneko Isamu
Kawaguchi Yasuhide
Kodama Shun-ichi
Okada Shinji
Takebe Yoko
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