Organopolysiloxane, temporary adhesive composition containing organopolysiloxane, and method of producing thinned wafer using the same

1. An organopolysiloxane obtained by subjecting an alkenyl group-containing organopolysiloxane (A1) to a hydrosilylation reaction with a hydrosilyl group-containing compound (A2) in the presence of a platinum group metal-based catalyst;

wherein the alkenyl group-containing organopolysiloxane (A1) is a non-aromatic saturated hydrocarbon group-containing organppolysiloxane containing the following units (I) to (III):

(I) a siloxane unit (T unit) represented by R 1 SiO 3/2 : 40 to 99 mol %;

(II) a siloxane unit (D unit) represented by R 2 R 3 SiO 2/2 : 59 mol % or less; and

(III) a siloxane unit (M unit) represented by R 4 R 5 R 6 SiO 1/2 : 1 to 30 mol %;

wherein:

R 1 to R 6 represents a monovalent organic group or a hydrogen atom;

40 mol % or more of all the organic groups and hydrogen atoms represented by R 1 to R 6 are each a non-aromatic saturated hydrocarbon group having 3 to 20 carbon atoms;

30 mol % or more of all the organic groups and hydrogen atoms represented by R 1 to R 3 may be the same or different and represent non-aromatic saturated hydrocarbon groups, having one of the following cyclic structures having 5 to 7 carbon atoms:

and,

the remainder of all the organic groups and hydrogen atoms represented by R 1 to R 6 may be the same or different and represent hydrogen atoms or substituted or unsubstituted monovalent hydrocarbon groups, having 1 to 7 carbon atoms, and

wherein 2 to 30 mol % of all the organic groups and hydrogen atoms represented by R 1 to R 6 are each an alkenyl group having 2 to 7 carbon atoms;

wherein the hydrosilyl group-containing compound (A2) is represented by the following average composition formula (1):

R 7 a R 8 b H c SiO (4-a-b-c)/2   (1),

wherein R 7 represents a monovalent organic group other than an alkenyl group; R 8 represents a divalent organic group; and a, b, and c represent positive numbers satisfying that: 0≦a≦2.5, 0≦b≦1, 0.75≦a+b≦2.5, 0.005≦c≦1, and 0.8≦a+b+c≦4,

wherein the hydrosilyl group-containing compound (A2) contains at least two SiH groups in one molecule, and

wherein the hydrosilyl group-containing compound (A2) is such content that the total molar amount of the SiH groups is 0.4 to 1.0 times a total molar amount of the alkenyl groups contained in the alkenyl group-containing organopolysiloxane (A1).

2. The organopolysiloxane according to claim 1 , wherein the hydrosilyl group-containing compound (A2) is an organohydrogenpolysiloxane having SiH groups at both ends, as represented by the following structural formula (3), or a bis-silyl compound having SiH groups at both ends, as represented by the following structural formula (4):

wherein n represents a positive number of 0 to 400; and R 12 to R 14 may be the same or different and represent substituted or unsubstituted monovalent organic groups;

wherein R 15 to R 17 may be the same or different and represent substituted or unsubstituted monovalent organic groups; and X represents a divalent organic group.

3. A temporary adhesive composition containing:

(A) the organopolysiloxane according to claim 2 ; and

(B) an organic solvent.

4. The temporary adhesive composition according to claim 3 , wherein the organic solvent (B) is a hydrocarbon solvent having a boiling point of 120 to 240° C.

5. A method of producing a thinned wafer by joining a wafer having a circuit-formed surface and a circuit-unformed surface to a supporting substrate, and by grinding the wafer, comprising:

a joining step for forming, on the circuit-formed surface and/or on the supporting substrate, an adhesive layer by the temporary adhesive composition according to claim 4 , and joining the wafer and the supporting substrate to each other through the adhesive layer therebetween;

a grinding step for grinding the circuit-unformed surface of the wafer joined to the supporting substrate;

a peeling step for peeling the wafer after grinding, from the supporting substrate at the adhesive layer; and

a removing step for removing the adhesive layer remaining on the circuit-formed surface of the peeled wafer.

6. A method of producing a thinned wafer by joining a wafer having a circuit-formed surface and a circuit-unformed surface to a supporting substrate, and by grinding the wafer, comprising:

a joining step for forming, on the circuit-formed surface and/or on the supporting substrate, an adhesive layer by the temporary adhesive composition according to claim 3 , and joining the wafer and the supporting substrate to each other through the adhesive layer therebetween;

a grinding step for grinding the circuit-unformed surface of the wafer joined to the supporting substrate;

a peeling step for peeling the wafer after grinding, from the supporting substrate at the adhesive layer; and

a removing step for removing the adhesive layer remaining on the circuit-formed surface of the peeled wafer.

7. A temporary adhesive composition containing:

(A) the organopolysiloxane according to claim 1 ; and

(B) an organic solvent.

8. The temporary adhesive composition according to claim 7 , wherein the organic solvent (B) is a hydrocarbon solvent having a boiling point of 120 to 240° C.

9. A method of producing a thinned wafer by joining a wafer having a circuit-formed surface and a circuit-unformed surface to a supporting substrate, and by grinding the wafer, comprising:

a joining step for forming, on the circuit-formed surface and/or on the supporting substrate, an adhesive layer by the temporary adhesive composition according to claim 8 , and joining the wafer and the supporting substrate to each other through the adhesive layer therebetween;

a grinding step for grinding the circuit-unformed surface of the wafer joined to the supporting substrate;

a peeling step for peeling the wafer after grinding, from the supporting substrate at the adhesive layer; and

a removing step for removing the adhesive layer remaining on the circuit-formed surface of the peeled wafer.

10. A method of producing a thinned wafer by joining a wafer having a circuit-formed surface and a circuit-unformed surface to a supporting substrate, and by grinding the wafer, comprising:

a joining step for forming, on the circuit-formed surface and/or on the supporting substrate, an adhesive layer by the temporary adhesive composition according to claim 7 , and joining the wafer and the supporting substrate to each other through the adhesive layer therebetween;

a grinding step for grinding the circuit-unformed surface of the wafer joined to the supporting substrate;

a peeling step for peeling the wafer after grinding, from the supporting substrate at the adhesive layer; and

a removing step for removing the adhesive layer remaining on the circuit-formed surface of the peeled wafer.

11. An organopolysiloxane obtained by subjecting a hydrosilyl group-containing organopolysiloxane (A3) to a hydrosilylation reaction with an alkenyl group-containing compound (A4) in the presence of a platinum group metal-based catalyst;

wherein the hydrosilyl group-containing organopolysiloxane (A3) is a non-aromatic saturated hydrocarbon group-containing organopolysiloxane containing the following units (I) to (III):

(I) a siloxane unit (T unit) represented by R 1 SiO 3/2 : 40 to 99 mol %;

(II) a siloxane unit (D unit) represented by R 2 R 3 SiO 2/2 : 59 mol % or less; and

(III) a siloxane unit (M unit) represented by R 4 R 5 R 6 SiO 1/2 : 1 to 30 mol %;

wherein:

R 1 to R 6 represents a monovalent organic group or a hydrogen atom;

40 mol % or more of all the organic groups and hydrogen atoms represented by R 1 to R 6 are each a non-aromatic saturated hydrocarbon group having 3 to 20 carbon atoms;

30 mol % or more of all the organic groups and hydrogen atoms represented by R 1 to R 3 may be the same or different and represent non-aromatic saturated hydrocarbon groups, having one of the following cyclic structures having 5 to 7 carbon atoms:

and,

the remainder of all the organic groups and hydrogen atoms represented by R 1 to R 6 may be the same or different and represent hydrogen atoms or substituted or unsubstituted monovalent hydrocarbon groups, having 1 to 7 carbon atoms, and wherein 2 to 20 mol % of all the organic groups and hydrogen atoms represented by R 1 to R 6 are each a hydrogen atom;

wherein the alkenyl group-containing compound (A4) is represented by the following average composition formula (2):

R 9 d R 10 e R 11 f SiO (4-d-e-f)/2   (2),

wherein R 9 represents a monovalent organic group other than an alkenyl group; R 10 represents a divalent organic group; R 11 represents an alkenyl group having 2 to 6 carbon atoms; d, e, and f represent positive numbers satisfying that: 0<d≦2, 0≦e≦1, 0.75≦d+e≦3, 0.01≦f≦1, and 0.8≦d+e+f≦4,

wherein the alkenyl group-containing compound (A4) contains at least two alkenyl groups in one molecule, and

wherein the alkenyl group-containing compound (A4) is such content that the total molar amount of the alkenyl groups is 1.0 to 2.5 times a total molar amount of the SiH groups contained in the hydrosilyl group-containing organopolysiloxane (A3).

12. A temporary adhesive composition containing:

(A) the organopolysiloxane according to claim 11 ; and

(B) an organic solvent.

13. The temporary adhesive composition according to claim 12 , wherein the organic solvent (B) is a hydrocarbon solvent having a boiling point of 120 to 240° C.

14. A method of producing a thinned wafer by joining a wafer having a circuit-formed surface and a circuit-unformed surface to a supporting substrate, and by grinding the wafer, comprising:

a joining step for forming, on the circuit-formed surface and/or on the supporting substrate, an adhesive layer by the temporary adhesive composition according to claim 13 , and joining the wafer and the supporting substrate to each other through the adhesive layer therebetween;

a grinding step for grinding the circuit-unformed surface of the wafer joined to the supporting substrate;

a peeling step for peeling the wafer after grinding, from the supporting substrate at the adhesive layer; and

a removing step for removing the adhesive layer remaining on the circuit-formed surface of the peeled wafer.

15. A method of producing a thinned wafer by joining a wafer having a circuit-formed surface and a circuit-unformed surface to a supporting substrate, and by grinding the wafer, comprising:

a joining step for forming, on the circuit-formed surface and/or on the supporting substrate, an adhesive layer by the temporary adhesive composition according to claim 12 , and joining the wafer and the supporting substrate to each other through the adhesive layer therebetween;

a grinding step for grinding the circuit-unformed surface of the wafer joined to the supporting substrate;

a peeling step for peeling the wafer after grinding, from the supporting substrate at the adhesive layer; and

a removing step for removing the adhesive layer remaining on the circuit-formed surface of the peeled wafer.