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
2001-04-05
2004-02-17
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, C526S270000, C526S281000, C526S320000
Reexamination Certificate
active
06692889
ABSTRACT:
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/JP00/05168 which has an International filing date of Aug. 2, 2000, which designated the United States of America.
TECHNICAL FIELD
The present invention relates to a polymeric compound which is useful as a photoresist resin for use in, for example, the micromachining of semiconductors, and to a photoresist resin composition which contains this polymeric compound.
BACKGROUND ART
Positive photoresists for use in manufacturing processes of semiconductors must coincidentally have different characteristics such as a characteristic that an exposed portion is made soluble in alkali by light irradiation, adhesion to silicon wafers, plasma-etching resistance, and transparency to light used. The positive photoresist is generally used as a solution containing a base component polymer, a light-activatable acid generator, and several types of additives for controlling the above characteristics. It is very important for the base component polymer to have the above individual characteristics in balance in order to prepare an appropriate resist according to its use.
The wavelength of a light source in lithography for use in semiconductor manufacturing becomes shorter and shorter in recent years, and ArF excimer laser with a wavelength of 193 nm is promising as a next-generation light source. The use of a unit containing an alicyclic hydrocarbon skeleton has been proposed as a monomer unit for a resist polymer for use in the ArF excimer laser exposure system (e.g., Japanese Patent No. 2776273). Such an alicyclic hydrocarbon skeleton is highly transparent with respect to light with the aforementioned wavelength and is resistant to etching. The use of a polymer having an adamantane skeleton as a resist polymer is also known, which adamantane skeleton exhibits especially high etching resistance among alicyclic hydrocarbon skeletons. However, such alicyclic hydrocarbon skeletons are highly hydrophobic and have therefore low adhesion to substrates, although they have high etching resistance as mentioned above. To relieve this disadvantage, the aforementioned Japanese patent therefore proposes a copolymer containing highly hydrophilic monomer units (adhesion-imparting monomer units) having, for example, a carboxyl group or a lactone ring. However, these monomer units are not resistant to etching, and the etching resistant of the overall polymer becomes insufficient when the polymer contains a sufficient amount of the monomer units to satisfy the required adhesion.
Separately, Japanese Unexamined Patent Application Publication No. 11-109632 has a try at imparting hydrophilicity to an adamantane skeleton by introducing a hydroxyl group thereto. However, the polymer proposed in the publication uses t-butyl (meth)acrylate as a monomer unit (alkali-soluble monomer unit) which becomes soluble in alkali by action of an acid generated by light irradiation, and the etching resistance of the overall polymer is still insufficient.
Attempts have been made to use a monomer unit having an adamantane skeleton itself as an alkali-soluble monomer unit (e.g., Japanese Unexamined Patent Application Publication No. 9-73173, Japanese Unexamined Patent Application Publication No. 9-90637, Japanese Unexamined Patent Application Publication No. 10-274852, Japanese Unexamined Patent Application Publication No. 10-319595, Japanese Unexamined Patent Application Publication No. 11-12326, and Japanese Unexamined Patent Application Publication No. 11-119434). However, monomers lacking etching resistance are used as the adhesion-imparting monomer units in these polymers, and the overall resulting polymers are still insufficient in etching resistance.
DISCLOSURE OF INVENTION
Accordingly, it is an object of the present invention to provide a polymeric compound having not only satisfactory transparency, alkali-solubility, and adhesion but also high etching resistance, as well as to provide a photoresist resin composition containing the polymeric compound.
After intensive investigations, the present inventors found that, when a polymer containing a monomer unit having an adamantane skeleton with a specific structure is used as a photoresist resin, the resulting photoresist resin has satisfactory etching resistance, in addition to excellent transparency, alkali-solubility and adhesion. The present invention has been accomplished based on these findings.
Specifically, the present invention provides, in an aspect, a polymeric compound which includes at least one monomer unit selected from among the following formulae (I), (II), (III) and (IV):
(wherein R
1
is a hydrogen atom or a methyl group, R
2
and R
3
are the same or different and are each a hydrogen atom, a hydroxyl group or a —COOR
4
group, where R
4
is a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or an 2-oxepanyl group; R
5
and R
6
are the same or different and are each a hydrogen atom, a hydroxyl group or an oxo group; R
7
, R
8
and R
9
are the same or different and are each a hydrogen atom or a methyl group; R
10
and R
11
are the same or different and are each a hydrocarbon group having 1 to 8 carbon atoms; R
12
, R
13
and R
14
are the same or different and are each a hydrogen atom, a hydroxyl group or a methyl group, where if all of R
12
to R
14
are each a hydrogen atom or a hydroxyl group, R
10
and R
11
are not coincidentally methyl groups)
[wherein, when the polymeric compound comprises a monomer unit of Formula (II) in which R
5
═R
6
═H or comprises a monomer unit of Formula (III), the polymeric compound further comprises at least one monomer unit selected from among a monomer unit represented by Formula (I), a monomer unit of Formula (II) in which at least one of R
5
and R
6
is a hydroxyl group or an oxo group, a monomer unit represented by Formula (IV) and a monomer unit represented by the following Formula (V):
(wherein R
15
and R
16
are the same or different and are each a hydrogen atom, a hydroxyl group or a carboxyl group; R
17
is a hydroxyl group, an oxo group or a carboxyl group; and R
1
has the same meaning as defined above)].
The polymeric compound may include at least one monomer unit selected from among Formulae (I), (II) and (III); and at least one monomer unit represented by Formula (V).
Alternatively, the polymeric compound may include at least one monomer unit represented by Formula (IV); and at least one monomer unit (excluding the monomer unit represented by Formula (IV)) selected from the following formulae (VI) and (II):
(wherein R
1
is a hydrogen atom or a methyl group; R
18
and R
19
are the same or different and are each a hydrocarbon group having 1 to 8 carbon atoms; R
20
and R
21
are the same or different and are each a hydrogen atom, a hydroxyl group, a carboxyl group or a —COOR group; R
22
is a hydroxyl group, an oxo group, a carboxyl group or a —COOR group, where R is a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or an 2-oxepanyl group; m denotes 0 or 1; and R
5
and R
6
are the same or different and are each a hydrogen atom, a hydroxyl group or an oxo group).
The polymeric compound may further include at least one monomer unit selected from among a monomer unit represented by the following Formula (VII):
(wherein R
1
and R
23
are the same or different and are each a hydrogen atom or a methyl group),
a monomer unit represented by the following Formula (VIII):
(wherein R
24
is a tricyclo[5.2.1.0
2,6
]decylmethyl group, a tetracyclo[4.4.0.1
2,5
.1
7,10
]dodecylmethyl group, a norbornyl group, an isobornyl group or a 2-norbornylmethyl group; R is a substituent of R
24
and is a hydrogen atom, a hydroxyl group, a hydroxymethyl group, a carboxyl group or a —COOR
26
group, where R
26
is a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or an 2-oxepanyl group; and R
1
has the same meaning as defined above),
a monomer unit represented by the following Formula (IX):
(wherein R
27
, R
28
, R
29
, R
Funaki Yoshinori
Inoue Keizo
Takaragi Akira
Tsutsumi Kiyoharu
Ashton Rosemary
Daicel Chemical Industries Ltd.
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