Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-10-19
2003-04-22
Pezzuto, Helen L. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S266000, C526S268000, C526S270000, C526S280000, C526S281000, C526S284000
Reexamination Certificate
active
06552143
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a polymeric compound for photoresist, to a resin composition for photoresist containing the polymeric compound, and to a method of manufacturing a semiconductor. Such photoresists are for use in, for example, fine patterning of semiconductors.
BACKGROUND ART
Positive photoresists for use in manufacturing processes of semiconductors must concurrently have different characteristics such as a characteristic that exposed portions become soluble in alkali by light irradiation, adhesion to silicon wafers, plasma-etching resistance, and transparency to light used. The positive photoresists are 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 in accordance with its use.
The wavelength of a lithographic light source for use in the manufacture of semiconductors 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 alicyclic hydrocarbon skeletons are highly transparent with respect to light with the aforementioned wavelength and are 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 therefore exhibit low adhesion to substrates, although they have high etching resistance as mentioned above. To relieve this disadvantage, the aforementioned Japanese patent therefore proposes copolymers containing a highly hydrophilic monomer unit (an adhesion-imparting monomer unit) having, for example, a carboxyl group or a lactone ring. However, even these polymers do not always have sufficient adhesion to substrates. Additionally, the monomer units are not resistant to etching, and the etching resistance of the entire polymer becomes insufficient when the polymer contains such a sufficient amount of the monomer unit as to satisfy the required adhesion.
Japanese Unexamined Patent Application Publication No. 11-109632 makes an attempt to impart hydrophilicity to a polymer by introducing a hydroxyl group to an adamantane skeleton. However, if adhesion is improved by action of a hydroxyl-group-containing monomer unit alone, an alkali developer generally makes the resulting resist film swell, thus frequently inviting flexure or waviness in the resulting pattern.
DISCLOSURE OF INVENTION
Accordingly, an object of the present invention is to provide a polymeric compound for photoresist, which can satisfactorily adhere to substrates and can form fine patterns with high precision.
Another object of the present invention is to provide a polymeric compound for photoresist, which can satisfactorily adhere to substrates and has satisfactory transparency, alkali-solubility and etching resistance.
A further object of the present invention is to provide a resin composition for photoresist and a method of manufacturing a semiconductor, which can form fine patterns with high precision.
After intensive investigations to achieve the above objects, the present inventors have found that, when a polymer containing a monomer unit that has an alicyclic skeleton of a specific structure having a lactone ring is used as a photoresist resin, the resulting photoresist resin has markedly improved adhesion to substrates, is resistant to swelling in a developer and can form fine patterns with high precision. The present invention has been accomplished based on these findings.
Specifically, the present invention provides a polymeric compound for photoresist, which includes a monomer unit represented by following Formula (I):
The polymeric compound may include the monomer unit represented by Formula (I) and at least one selected from monomer units represented by following Formulae (IIa) to (IIg):
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 hydrocarbon group having from 1 to 8 carbon atoms; R
4
, R
5
and R
6
are the same or different and are each a hydrogen atom, a hydroxyl group or a methyl group; R
7
and R
8
are the same or different and are each a hydrogen atom, a hydroxyl group or a —COOR
9
group, where R
9
is a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or an 2-oxepanyl group; R
10
and R
11
are the same or different and are each a hydrogen atom, a hydroxyl group or an oxo group; R
12
is a hydrocarbon group having a tertiary carbon atom at a bonding site with an oxygen atom indicated in the formula; R
13
, R
14
and R
15
are the same or different and are each hydrogen atom or a methyl group; R
16
is a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or an 2-oxepanyl group; and n denotes an integer from 1 to 3.
The polymeric compound may further include at least one selected from monomer units represented by following Formulae (IIIa) to (IIIg):
wherein R
1
is a hydrogen atom or a methyl group; R
17
and R
18
are the same or different and are each a hydrogen atom, a hydroxyl group or a carboxyl group; R
19
is a hydroxyl group, an oxo group or a carboxyl group; R
20
, R
21
, R
22
, R
23
and R
24
are the same or different and are each a hydrogen atom or a methyl group; R
25
is a hydrogen atom or a methyl group; R
26
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; and R
27
is a substituent of R
26
and is a hydrogen atom, a hydroxyl group, a hydroxymethyl group, a carboxyl group or a —COOR
28
group, where R
28
is a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or an 2-oxepanyl group.
The present invention further provides a resin composition for photoresist, which includes the polymeric compound for photoresist and a light-activatable acid generator. In addition, the present invention provides a method of manufacturing a semiconductor, which method includes the steps of applying the resin composition for photoresist onto a base or substrate to thereby form a resist film, and subjecting the resist film to exposure and development to thereby produce a pattern.
In the present description, the terms “acrylic” and “methacrylic” may be generically referred to as “(meth)acrylic”, and the terms “acryloyl” and “methacryloyl” may be generically referred to as “(meth)acryloyl”.
BEST MODE FOR CARRYING OUT THE INVENTION
Polymeric compounds for photoresist of the present invention comprise the monomer unit (constitutional repeating unit) represented by Formula (I) (hereinafter referred to as “Monomer Unit 1”). Monomer Unit 1 has a highly hydrophilic lactone ring and improves adhesion to substrate to thereby serve as a unit for imparting adhesion. It also has an alicyclic carbon ring (a norbornane ring), has the function of improving etching resistance and is resistant to swelling in an alkali developer. By using appropriate polymerizable monomers having the function of being soluble in alkali, the function of being resistant to etching, and other functions as comonomers in production of polymers, the resulting polymers have necessary functions as resists. Such polymers containing Monomer Unit 1 can be advantageously used as photoresist resins.
A polymeric compound as a preferred embodiment of the present invention includes the monomer unit represented by Formula (I) and at least one monomer unit (a constitutional repeating unit) (hereinafter referred to as “Monomer Unit 2”) selected from those represented b
Funaki Yoshinori
Takaragi Akira
Tsutsumi Kiyoharu
Birch & Stewart Kolasch & Birch, LLP
Daicel Chemical Industries Ltd.
Pezzuto Helen L.
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