	US 12,112,976 B2
	Pseudo-substrate with improved efficiency of usage of single crystal material
Fabrice Letertre, Grenoble (FR); and Oleg Kononchuk, Theys (FR)
Assigned to Soitec, Bernin (FR)
Filed by Soitec, Bernin (FR)
Filed on Nov. 3, 2020, as Appl. No. 17/088,426.
Application 17/088,426 is a continuation of application No. 14/422,596, granted, now 10,910,256, previously published as PCT/IB2013/001940, filed on Sep. 6, 2013.
Claims priority of application No. 1258227 (FR), filed on Sep. 4, 2012.
Prior Publication US 2021/0050248 A1, Feb. 18, 2021
Int. Cl. H01L 21/762 (2006.01); B32B 7/12 (2006.01); B32B 9/04 (2006.01); B32B 38/00 (2006.01); C30B 29/68 (2006.01); C30B 33/00 (2006.01); C30B 33/06 (2006.01); H01L 21/02 (2006.01); H01L 21/18 (2006.01); H01L 27/12 (2006.01); H01L 33/00 (2010.01)

CPC H01L 21/76251 (2013.01) [B32B 7/12 (2013.01); B32B 9/04 (2013.01); C30B 29/68 (2013.01); C30B 33/00 (2013.01); C30B 33/06 (2013.01); H01L 21/02002 (2013.01); H01L 21/185 (2013.01); H01L 27/1203 (2013.01); B32B 2457/14 (2013.01); H01L 33/0093 (2020.05); Y10T 156/1062 (2015.01); Y10T 428/24942 (2015.01)]

23 Claims

1. A method for fabricating at least one pseudo-substrate, comprising:

cutting a thin piezoelectric layer from a single crystal ingot comprising a piezoelectric material, to provide the thin piezoelectric layer comprising a first rough cut surface and a second surface opposite to the first rough cut surface of the single crystal ingot comprising a rough cut surface;

providing a bonding layer on the first rough cut surface of the thin piezoelectric layer without polishing the first rough cut surface of the thin piezoelectric layer, the bonding layer comprising a front surface and a back surface, the front surface of the bonding layer adhering to the first rough cut surface of the thin piezoelectric layer; and

bonding the back surface of the bonding layer to a handle substrate without polishing the back surface of the bonding layer prior to the bonding,

wherein the handle substrate has a matching coefficient of thermal expansion with respect to the thin piezoelectric layer, and

wherein a thickness of the thin piezoelectric layer is 300 μm or less.