US 12,451,854 B2
Method for manufacturing composite substrate
Shoji Akiyama, Gunma (JP)
Assigned to SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Appl. No. 17/919,858
Filed by Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
PCT Filed Apr. 6, 2021, PCT No. PCT/JP2021/014658
§ 371(c)(1), (2) Date Oct. 19, 2022,
PCT Pub. No. WO2021/220737, PCT Pub. Date Nov. 4, 2021.
Claims priority of application No. 2020-080805 (JP), filed on Apr. 30, 2020.
Prior Publication US 2023/0163744 A1, May 25, 2023
Int. Cl. H03H 3/08 (2006.01); C30B 29/30 (2006.01); C30B 33/06 (2006.01); C30B 33/08 (2006.01); H03H 9/02 (2006.01); H03H 9/25 (2006.01); H10N 30/072 (2023.01); H10N 30/073 (2023.01)
CPC H03H 3/08 (2013.01) [C30B 29/30 (2013.01); C30B 33/06 (2013.01); C30B 33/08 (2013.01); H03H 9/02559 (2013.01); H03H 9/02574 (2013.01); H03H 9/25 (2013.01); H10N 30/072 (2023.02); H10N 30/073 (2023.02); Y10T 29/42 (2015.01)] 9 Claims
OG exemplary drawing
 
1. A method for manufacturing composite substrate comprising:
preparing a piezoelectric material substrate having a first rough surface and a damaged layer in a vicinity of the first rough surface, wherein a surface roughness of the first rough surface is greater than about 0.03 μm in arithmetic mean roughness Ra, and wherein cracks exist within the damaged layer;
removing the damaged layer by etching the first rough surface of the piezoelectric material substrate using a chemical process;
depositing an intervening layer on a second rough surface of the piezoelectric material substrate from which the damaged layer has been removed, wherein a surface roughness of the second rough surface is greater than about 0.03 μm in arithmetic mean roughness Ra;
flattening a surface of the deposited intervening layer;
bonding the piezoelectric material substrate to a support substrate having a lower thermal expansion coefficient than the piezoelectric material substrate, wherein the deposited intervening layer is in between the piezoelectric material substrate and the support substrate; and
thinning the piezoelectric material substrate after bonding the piezoelectric material substrate to the support substrate,
wherein the piezoelectric material substrate is Lithium tantalate (LT) or lithium niobate (LN).