Patent ID: 9245760
Filing Date: 2016-01-26
CPC Classification: H01L

Claim Text:
1. A method of forming a semiconductor device, the method comprising: forming a first porous semiconductor layer over a top surface of a substrate; forming a first epitaxial layer over the first porous semiconductor layer, wherein forming the first porous semiconductor layer comprises depositing an epitaxial layer and electrochemically etching at least a portion of the epitaxial layer, wherein depositing the epitaxial layer comprises forming a first layer having a first doping, and a second layer having a second doping different from the first layer; forming stressor structures in the first epitaxial layer; forming circuitry within and over the first epitaxial layer, wherein the circuitry is formed without completely oxidizing the first epitaxial layer; forming a second porous semiconductor layer between the top surface of the substrate and the first porous semiconductor layer; forming a second epitaxial layer between the first porous semiconductor layer and the second porous semiconductor layer; thinning the substrate from a back surface to form an intermediate structure; and dicing the intermediate structure to form singulated chips, wherein the thinning removes the second porous semiconductor layer, and wherein the thinning is stopped before reaching the first porous semiconductor layer.