Insulating-film forming material and insulating film using the same

1. An insulating-film forming material comprising a polymer (A) that has, as a repeating unit thereof, a structure represented by the following general formula (I):

wherein R 1 to R 7 are the same or different, and each represents a monovalent group;

one of X, Y and Z represents a group represented by formula (IA), and another one of X, Y and Z is —O—, and the other one of X, Y and Z is a group represented by formula (IB) wherein the oxygen atom that directly bonds to the silicon atom in formula (IB) is also connected to formula (I); and

n indicates an integer of from 1 to 10:

wherein R 8 to R 10 are the same or different, and each represents a monovalent group,

wherein R 11 to R 14 are the same or different, and each represents a monovalent group;

R 15 to R 17 are the same or different, and each represents a single bond or a divalent group;

R 18 represents a single bond or —O—;

m indicates an integer of from 0 to 10; and

at least one of R 1 to R 17 in formula (I) includes at least one carbon-carbon triple bond or is a monovalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction.

2. The insulating-film forming material as claimed in claim 1 , wherein R 1 to R 14 in formula (I) are the same or different, and each represents a hydroxyl group, a monovalent hydrocarbon group, a monovalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction, a group derived from a monovalent hydrocarbon group by substituting a part of the carbon atom(s) in the monovalent hydrocarbon group with a silicon atom, or a group derived from a monovalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction, by substituting a part of the carbon atom(s) in the monovalent group with a silicon atom, and R 15 to R 17 are the same or different, and each represents a single bond, a divalent hydrocarbon group, or a divalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction, provided that at least one of R 1 to R 17 in formula (I) includes at least one carbon-carbon triple bond or is a monovalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction.

3. An insulating film obtained by using an insulating-film forming material as claimed in claim 1 .

4. A porous insulating-film forming material comprising:

a polymer that has, as a repeating unit thereof, a structure represented by formula (I); and

at least one of a compound (B-1) and particles (B-2),

(B-1) a compound having a boiling or decomposition point of 250° C. to 450° C.,

(B-2) hollow particles:

wherein R 1 to R 7 are the same or different, and each represents a monovalent group;

one of X, Y and Z represents a group represented by formula (IA), and another one of X, Y and Z is —O—, and the other one of X, Y and Z is a group represented by formula (IB) wherein the oxygen atom that directly bonds to the silicon atom in formula (IB) is also connected to formula (I); and

n indicates an integer of from 1 to 10:

wherein R 8 to R 10 are the same or different, and each represents a monovalent group,

wherein R 11 to R 14 are the same or different, and each represents a monovalent group;

R 15 to R 17 are the same or different, and each represents a single bond or a divalent group;

R 18 represents a single bond or —O—;

m indicates an integer of from 0 to 10; and

at least one of R 1 to R 17 in formula (I) includes at least one carbon-carbon triple bond or is a monovalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction.

5. A porous insulating-film forming material comprising a polymer that has, as a repeating unit thereof, a structure represented by formula (I′):

wherein R 1 to R 7 are the same or different, and each represents a monovalent group; one of X, Y and Z represents a group represented by formula (IA), and another one of X, Y and Z is —O—, and the other one of X, Y and Z is a group represented by formula (IB) wherein the oxygen atom that directly bonds to the silicon atom in formula (IB) is also connected to formula (I′); and

n indicates an integer of from 1 to 10:

wherein R 8 to R 10 are the same or different, and each represents a monovalent group,

wherein R 11 to R 14 are the same or different, and each represents a monovalent group;

R 15 to R 17 are the same or different, and each represents a single bond or a divalent group;

R 18 represents a single bond or —O—;

m indicates an integer of from 0 to 10; and

at least one of R 1 to R 17 in formula (I) includes at least one carbon-carbon triple bond or is a monovalent group capable of becoming a hydrocarbon group though a Diels-Alder reaction followed by an elimination reaction.

6. The porous insulating-film forming material as claimed in claim 4 , wherein at least one of R 1 to R 17 in formula (I) additionally satisfies at least one of the following conditions (α) and (β):

(α) at least one of R 1 to R 14 is a monovalent hydrocarbon group, a monovalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction, a group derived from a monovalent hydrocarbon group by substituting a part of the carbon atom(s) in the monovalent hydrocarbon group with a silicon atom, or a group derived from a monovalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction, by substituting a part of the carbon atom(s) in the monovalent group with a silicon atom; and

(β) at least one of R 15 to R 17 is a divalent hydrocarbon group, or a divalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction.

7. The porous insulating-film forming material as claimed in claim 5 , wherein at least one of R 1 to R 17 in formula (I′) additionally satisfies at least one of the following conditions (α) and (β):

(α) at least one of R 1 to R 14 is a monovalent hydrocarbon group, a monovalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction, a group derived from a monovalent hydrocarbon group by substituting a part of the carbon atom(s) in the monovalent hydrocarbon group with a silicon atom, or a group derived from a monovalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction, by substituting a part of the carbon atom(s) in the monovalent group with a silicon atom; and

(β) at least one of R 15 to R 17 is a divalent hydrocarbon group, or a divalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction.

8. A porous insulating film obtained by using an insulating-film forming material as claimed in claim 4 .

9. A porous insulating film obtained by using an insulating-film forming material as claimed in claim 5 .

10. The insulating-film forming material as claimed in claim 1 , wherein at least one of R 1 to R 17 in formula (I) satisfies the condition that at least one of R 1 to R 17 includes at least one carbon-carbon triple bond.

11. The insulating-film forming material as claimed in claim 1 , wherein at least one of R 1 to R 17 in formula (I) is a monovalent group capable of becoming a hydrocarbon group through a Diels-Alder reaction followed by an elimination reaction.

12. The insulating film as claimed in claim 3 , wherein the insulating film is obtained by coating a substrate with the insulating-film forming material as claimed in claim 1 and then drying and heating the insulating-film forming material.