| abstract |
An object of the present invention is to provide an insulating layer for a printed wiring board capable of reducing warpage during manufacture of a semiconductor plastic package. The insulating layer includes a resin composition including an alkenyl-substituted nadicimide (A), a maleimide compound (B), a cyanate compound (C) and an inorganic filler (D), the The content of the cyanate ester compound (C) is 5 to 15 parts by mass with respect to 100 parts by mass of the total of the components (A) to (C), and the number of maleimide groups (β) of the maleimide compound (B) is ) to the alkenyl group number (α) of the alkenyl-substituted nadicimide (A) ([β/α]) is 0.9 to 4.3, and the difference between the flexural modulus at 25°C and the thermal flexural modulus at 250°C within 20%. |