Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2001-04-13
2004-03-16
Szekely, Peter (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C525S403000, C525S405000
Reexamination Certificate
active
06706850
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a polyether copolymer, a process for producing the same, a coating solution for forming a porous organic film that is suitable as an insulating film usable in electronic devices and a process for forming a porous organic film.
2. Description of Related Art
Speeding up of LSI can be attained by fining of transistors constituting it. In recent years, the shrinking design rule of IC, LSI and the like has led to increased interconnection delay (RC delay) caused by parasitic capacity in an insulation film. For solving interconnection delay, it is desired that an insulation film has lower dielectric constant. These have become important problems that inhibit upgrading of performance of LSI itself. As a means for solving these problems, lowering of dielectric constant of insulating film filled between wires has been considered.
Dielectric constant is generally proportional to the density and electronic polarizability of material itself, as indicated in Clausis-Mosotti's formula. Therefore, dielectric constant can be lowered by diminishment of density when a material is made porous. For example, JP-A-8-162450 and JP-A-10-70121 disclose methods for obtaining porous silica films by mixing fine particles of silica with an alkoxysilane or a partial hydrolysis thereof thus controlling the shrinkage factor. In these methods, however, because not only the water absorption of silica film itself is significant but also the surface area increases by making porous, the water absorption and dielectric constant of silica film are liable to increase. A hydrophobic treatment of a surface of silica film becomes necessary as a countermeasure against it, and as the result, throughput is lowered.
Japanese Patent Specification No. 2,531,906 discloses an attempt in which a porous material of an organic resin, which has a lower water absorption and generally a lower dielectric constant as compared with silica, is used as an insulating film for electronic devices.
SUMMARY OF THE INVENTION
The objective of the invention is to provide a coating solution for forming a porous organic film that allows lowering of dielectric constant for use as an insulating material used in electronic parts and a process for forming a porous organic film, as well as a polyether copolymer used in said coating film and a process for producing the same.
As the result of an extensive study for a coating solution capable of forming a porous film usable in electronic parts and for a process for forming said porous organic film, the present inventors have found that the above purpose can be attained by a coating solution containing a polymer having a moiety that causes thermal decomposition at a relatively low temperature in a molecular chain and an organic solvent, and have completed the present invention.
Said coating solution can be applied easily on a substrate, and capable of forming uniform fine voids by decomposition of thermally decomposable moiety.
Therefore, the invention relates to the following [1]-[16]:
[1] A polyether copolymer comprising (A) an aromatic polyether block and (B) an aliphatic polyether block.
[2] A polyether copolymer according to [1], wherein (B) an aliphatic polyether block is on a side chain of (A) an aromatic polyether block.
[3] The polyether copolymer according to [1] or [2], wherein the aromatic polyether block (A) has a structural unit represented by the following formula (1):
wherein R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
and R
8
are independently selected from the group consisting of a hydrogen atom, a chlorine atom, an iodine atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a cycloalkyl group having 4 to 10 carbon atoms, a methoxy group, an ethoxy group, a phenyl group which may be substituted and a functional group represented by the formula (2) or (3) described below; Y
1
is selected from any one of functional groups described below or two or more of the functional groups; Y
2
is selected from any one of a single bond, a hydrocarbon group having 1 to 20 carbon atoms, an ether group, a ketone group and a sulfone group or two or more of them; at least one of R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
and R
8
or Q
1
, Q
2
, Q
3
, Q
4
, Q
5
, Q
6
, Q
7
, Q
8
, Q
9
, Q
10
, Q
11
, Q
12
and Q
13
in at least one unit structure contained in a molecular chain is selected from functional groups represented by the formula (3);
wherein and Q
1
, Q
2
, Q
3
, Q
4
, Q
5
, Q
6
, Q
7
, Q
8
, Q
9
, Q
10
, Q
11
and Q
12
are independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms and a functional group represented by the formula (2) or (3) described below; Q
13
is selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms and a functional group represented by the formula (2) or (3); Z is selected from the group consisting of a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a group —OZ
1
and a group —NZ
2
Z
3
; and Z
1
, Z
2
and Z
3
are independently selected from the group consisting of a hydrogen atom, a saturated or unsaturated hydrocarbon group and an ether bond-containing group;
wherein T
1
is selected from an alkenyl group having 2 to 10 carbon atoms; T
2
is selected from an alkyl group having 1 to 10 carbon atoms and an aryl group; n represents an integer of 1 to 3 inclusive; plural T
1
's may be different from each other and plural T
2
's may also be different from each other;
wherein R
9
is selected from a single bond and a hydrocarbon group having 1 to 10 carbon atoms; R
10
is selected from a hydrocarbon group having 1 to 10 carbon atoms; R
11
is selected from a hydrogen atom and a hydrocarbon group having 1 to 10 carbon atoms; and m is selected from an integer of 1 or more.
[4] The polyether copolymer according to [3], wherein R
10
is —CH
2
—CH
2
—, —CH
2
—CH(CH
3
)— or —CH(CH
3
)—CH
2
—.
[5] The polyether copolymer according to any of [1] to [4], wherein the relation between the thermal decomposition starting temperature Ta (° C.) of the aromatic polyether block (A) and the thermal decomposition starting temperature Tb (° C.) of the aliphatic polyether block (B) is represented by the formula: Ta≧(Tb+40).
[6] A process for producing a polyether copolymer according to [1] to [5], wherein the process comprises reacting a bisphenol compound corresponding to the material for a moiety of the aromatic polyether block (A), a di-halogenated compound and an aliphatic polyether having an OH group at the terminal and corresponding to the material for a moiety of the aliphatic polyether block (B) in the presence of an alkali.
[7] The process according to [6], wherein a pre-reaction of the di-halogenated compound and the aliphatic polyether having an OH group at the terminal is carried out in the presence of an alkali, then the bisphenol compound and the di-halogenated compound are added to the reaction mixture and the reaction is continued in the presence of an alkali.
[8] A process according to any of [1] to [5], wherein the process comprises steps of metallizing an aromatic polyether corresponding to a moiety of (A), and carrying out a substitution reaction with a halide of an aliphatic polyether corresponding to a moiety of (B).
[9] A coating solution for forming a porous organic film comprising (a) a polyether copolymer according to any of [1] to [5] and (b) an organic solvent.
[10] A coating solution for forming a porous organic film comprising (c) a resi
Choi Hyuncheol
Yokota Akira
Yoshida Yuji
Birch & Stewart Kolasch & Birch, LLP
Sumitomo Chemical Company Limited
Szekely Peter
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