Substrate for mounting an optical semiconductor element, manufacturing method thereof, an optical semiconductor device, and manufacturing method thereof

1. 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.

2. The substrate according to claim 1 , wherein at least one of the external connection terminal formation opening portions is provided directly below a mounting position of an optical semiconductor element to be mounted in the depressed portion.

3. The substrate according to claim 1 , wherein said thermosetting optical reflection resin is a resin formed by curing a resin composition comprising an epoxy resin, a curing agent, a curing catalyst, an inorganic filler and a white pigment.

4. The substrate according to claim 3 , wherein said resin composition further includes a coupling agent.

5. The substrate according to claim 1 , wherein the thermosetting optical reflection resin has an optical reflectivity at wavelengths from 350 to 800 nm of 80% or higher.

6. The substrate according to claim 1 , wherein the resin material of the insulating layer is different from the thermosetting optical reflection resin of the optical reflection member.

7. The substrate according to claim 1 , wherein the insulating layer comprises a glass-reinforced resin board.

8. An optical semiconductor device, comprising:

the substrate for mounting an optical semiconductor element according to claim 1 ;

an optical semiconductor element mounted in a depressed-portion bottom face of the substrate for mounting an optical semiconductor element; and

a fluorescent material-containing transparent sealing resin layer formed within the depressed portion so as to cover the optical semiconductor element.

9. A method of manufacturing the substrate for mounting an optical semiconductor element according to claim 1 , comprising the steps of:

forming, on a base substrate having an insulating layer and a plurality of wiring circuits formed on the upper face of the insulating layer, at least one external connection terminal formation opening portion which penetrates the insulating layer and reaches the wiring circuits; and

forming an optical reflection member which, on the upper face of the base substrate, forms at least one depressed portion serving as an area for mounting an optical semiconductor element, wherein

at least the inner peripheral face of the optical reflection member formed in the depressed portion is formed from a thermosetting optical reflection resin composition which has, as essential components, (A) an epoxy resin, (B) a curing agent, (C) a curing catalyst, (D) an inorganic filler material, and (E) a white pigment.

10. The method according to claim 9 , wherein the optical reflection member is integrally molded by transfer molding of the thermosetting optical reflection resin composition onto the upper face of the base substrate having the plurality of wiring circuits.

11. The method according to claim 10 , wherein, prior to integral molding of the optical reflection member, a solder resist layer is formed on the plurality of wiring circuits.

12. A method of manufacturing an optical semiconductor device, comprising the steps of:

mounting at least one optical semiconductor element in a depressed-portion bottom face of the substrate for mounting an optical semiconductor element according to claim 1 ; and

forming a fluorescent material-containing transparent sealing resin layer within the depressed portion so as to cover the optical semiconductor element.

13. A method of manufacturing an optical semiconductor device, comprising the steps of:

mounting at least one optical semiconductor element in each of depressed portions of the substrate according to claim 1 , the substrate being provided with at least two depressed portions;

forming a fluorescent material-containing transparent sealing resin layer in each of the depressed portions so as to cover the optical semiconductor elements; and

dividing the two or more continuous optical semiconductor devices obtained in the preceding processes into separate optical semiconductor devices.