US 12,261,090 B2
Composite substrate and method of producing the composite substrate, and semiconductor device comprising the composite substrate
Masatsugu Ichikawa, Tokushima (JP); Shoichi Yamada, Anan (JP); Takeshi Kihara, Tokushima (JP); and Yutaka Matsusaka, Anan (JP)
Assigned to NICHIA CORPORATION, Anan (JP)
Filed by NICHIA CORPORATION, Anan (JP)
Filed on Jan. 31, 2024, as Appl. No. 18/428,088.
Application 18/428,088 is a division of application No. 17/489,595, filed on Sep. 29, 2021, granted, now 11,929,294.
Claims priority of application No. 2020-165563 (JP), filed on Sep. 30, 2020; and application No. 2021-124674 (JP), filed on Jul. 29, 2021.
Prior Publication US 2024/0222209 A1, Jul. 4, 2024
Int. Cl. H01L 23/14 (2006.01); H01L 21/48 (2006.01); H01L 23/373 (2006.01); B22D 21/00 (2006.01); C04B 41/88 (2006.01)
CPC H01L 23/142 (2013.01) [H01L 21/4882 (2013.01); H01L 23/3732 (2013.01); H01L 23/3733 (2013.01); B22D 21/007 (2013.01); C04B 41/88 (2013.01); H01L 21/4871 (2013.01); H01L 23/3736 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of producing a composite substrate, the method comprising:
providing a layered body, which comprises steps of:
providing a base layer formed of a composite material containing diamond and a metal, the base layer having a first surface, and a second surface opposite to the first surface, and
forming a metal layer on the first surface of the base layer and polishing a surface of the metal layer, thereby forming a flat layer having a lower surface bonded to the first surface of the base layer, and an upper surface having a surface roughness Ra of 10 nm or less; and
directly bonding an insulating layer to the upper surface of the flat layer.