US Patent 7563651 Method of fabricating a substrate with a concave surface

Bending generated in a side of a device mounting surface of an organic resin substrate after an assembly process for a semiconductor device is inhibited, thereby providing an improved production yield. A semiconductor device 100 is formed by solder-joining a semiconductor chip 105 onto a device mounting surface 111 of an interposer that is composed of an organic resin substrate 101. The interposer is an interposer, which is composed of an organic resin substrate 101, and on one surface of which a semiconductor chip 105 is to be mounted, and has a convex curvature in a side of a back surface 113 opposite to the device mounting surface 111, in a condition before an assembling process for the semiconductor device 100.