Adhesion-promoting agent, curable organopolysiloxane composition, and semiconductor device

A curable organopolysiloxane composition comprising at least the following components:

• 100 parts by weight of an organopolysiloxane (A) of the following average formula:
• R2bSiO(4-b)/2
• (where R2 is an optionally substituted univalent hydrocarbon group with 1 to 10 carbon atoms;
• however, in one molecule, at least two R2's are univalent hydrocarbon groups having unsaturated aliphatic bonds;
• at least 20 mole % of all R2's are aryl groups;
• and “b” is a number that satisfies the following condition:
• 0.5≦b≦2.2);
• an organohydrogenpolysiloxane (B) of the following average formula:
• R3cHdSiO(4-c-d)/2
• (where R3 is an optionally substituted univalent hydrocarbon group having 1 to 10 carbon atoms and free of unsaturated aliphatic bonds, and where “c” and “d” are numbers that satisfy the following conditions:
• 1.0<c<2.2;
• 0.002<d<1;
• and 1.0<c+d<3.0)
• wherein component (B) is contained in such an amount that the mole ratio of silicon-bonded hydrogen atoms contained in this component to univalent hydrocarbon groups with unsaturated aliphatic bonds contained in component (A) is in the range of 0.3 to 5;
• 0.01 to 50 parts by weight of an adhesion-promoting agent (C) represented by the following average formula:
• R1aSiO(4-a)/2
• (where R1 is a group selected from an optionally substituted alkyl group with 1 to 10 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, an aryl group with 6 to 20 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, or an epoxy-containing organic group;
• however, in one molecule, the content of alkenyl groups constitute at least 5 mole % of all groups designated by R1;
• the content of aryl groups constitute at least 5 mole % of all groups designated by R1;
• the content of alkoxy groups constitute at least 5 mole % of all groups designated by R1;
• the content of epoxy-containing organic groups constitute at least 5 mole % of all groups designated by R1;
• and “a” is a number that satisfies the following condition:
• 2.2≦a<2.6);
• and
• a hydrosilylation catalyst (D) in a catalytic quantity.