US 12,113,155 B2
Method of manufacturing optical semiconductor device and optical semiconductor device
Tsukasa Maruyama, Akita (JP); Takashi Araki, Inzai (JP); and Takehiro Miyaji, Akita (JP)
Assigned to DOWA Electronics Materials Co., Ltd., Tokyo (JP)
Appl. No. 17/754,113
Filed by DOWA Electronics Materials Co., Ltd., Tokyo (JP)
PCT Filed Sep. 18, 2020, PCT No. PCT/JP2020/035613
§ 371(c)(1), (2) Date Mar. 24, 2022,
PCT Pub. No. WO2021/060217, PCT Pub. Date Apr. 1, 2021.
Claims priority of application No. 2019-177597 (JP), filed on Sep. 27, 2019.
Prior Publication US 2022/0293825 A1, Sep. 15, 2022
Int. Cl. H01L 33/48 (2010.01); H01L 33/62 (2010.01)
CPC H01L 33/486 (2013.01) [H01L 33/62 (2013.01); H01L 2933/0066 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method of manufacturing an optical semiconductor device, comprising:
a mounting step of placing an optical semiconductor chip on a package substrate made of ceramic;
a storing step of storing the package substrate after the mounting step in a first dry atmosphere;
a placing step of subjecting the optical semiconductor chip on the package substrate to a second dry atmosphere and placing a light transparent window on a joint portion of the package substrate with a joint material therebetween; and
a sealing step of joining the joint portion and the light transparent window with the joint material in a low oxygen concentration atmosphere having an oxygen concentration of 1 vol % or less, thereby encapsulating the optical semiconductor chip in a confined space formed by the package substrate and the light transparent window,
wherein the confined space after the sealing step has a moisture concentration of 1000 ppm or less and an oxygen concentration of 3 vol % or less.