Patent ID: 8212271

Claim:
A substrate for mounting an optical semiconductor element, comprising: a base substrate, having an insulating layer of a resin material and a plurality of wiring circuits formed on the upper face of the insulating layer, the plurality of wiring circuits being located so as to be connected to the optical semiconductor element by wire bonding, and having at least one external connection terminal formation opening portion which penetrates the insulating layer and reaches the wiring circuits; and an optical reflection member, which is provided on the upper face of the base substrate, and which forms at least one depressed portion serving as an area for mounting an optical semiconductor element, wherein the optical reflection member comprises a thermosetting optical reflection resin, wherein inner faces of the external connection terminal formation opening portion are covered with a material with high thermal conductivity, and wherein an external connection terminal formed in the external connection terminal formation opening portion is any one of a solder ball, solder paste, an electrode pad, and a needle-shape terminal.