Curable organosilicon resin composition and semiconductor device

A curable organosilicon resin composition comprising:

• (A) 100 parts by weight of an organopolysiloxane of block polymer structure consisting of 30 to 80 mol % of R1SiO3/2 units, 10 to 70 mol % of (R1)2SiO2/2 units, and 0 to 30 mol % of (R1)3SiO1/2 units wherein Ri is independently a hydroxyl, C2-C10 alkenyl, C1-C10 substituted or unsubstituted alkyl, C1-C10 alkoxy or C6-C10 aryl group, in which at least some of the (R1)2SiO2/2 units continuously repeat and the average number of repeating units is 3 to 80, the organopolysiloxane having a weight average molecular weight of 5,000 to 100,000 and containing at least two silicon-bonded alkenyl groups per molecule, 0.001 to 1.0 mol/100 g of silicon-bonded hydroxyl groups, and up to 1.0 mol/100 g of silicon-bonded alkoxy groups,
• (B) an organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms (i.e., SiH groups) and at least one silicon-bonded aryl group per molecule, in an amount to give 0.1 to 4.0 moles of SiH groups in component (B) per mole of alkenyl groups in component (A),
• (C) a hydrosilylation catalyst in an amount to give 0.1 to 500 ppm of platinum group metal based on the total weight of components (A) and (B), and
• (D) a cyclic polysiloxane having the formula (1):
• wherein R4 is independently hydrogen, a C2-C10 alkenyl, C1-C10 substituted or unsubstituted alkyl or C6-C10 aryl group and n is an integer of 0 or 1, the cyclic polysiloxane being present in an amount of 0.1 to 30% by weight based on the total weight of components (A) and (B), and in an amount to give 0.1 to 4.0 moles of total SiH groups in components (B) and (D) per mole of total alkenyl groups in components (A) and (D) when component (D) has an alkenyl group and/or SiH group.