Semiconductor element mounting board

Abstract

A semiconductor element mounting board includes: a board having surfaces; a semiconductor element provided at a side of one of the surfaces of the board; a bonding agent layer through which the board and the semiconductor element are bonded together, the bonding agent layer having a storage modulus at 25° C. of 5 to 1,000 MPa; a first layer into which the semiconductor element is embedded, the first layer provided on the one surface of the board; a second layer provided on the other surface of the board, the second layer being constituted from the same material as that of the first layer, the constituent material of the second layer having the same composition ratio as that of the constituent material of the first layer; and surface layers provided on the first and second layers, respectively, each of the surface layers being formed from at least a single layer. In the semiconductor element mounting board, a coefficient of thermal expansion of each surface layer in an inplane direction thereof measured based on JIS C 6481 at a temperature of 20° C. to a glass-transition temperature Tga° C., which is measured based on JIS C 6481, is 40 ppm/° C. or lower.

Dependencies are inferred from the claim text.