Patent ID: 8846489
Filing Date: 2014-09-30
Classification: H01L

Abstract:
1. A trench isolation process, comprising: providing a substrate having thereon a pad layer and a hard mask layer; forming at least one opening in the hard mask layer; etching the substrate through the opening to thereby form a first trench; forming a spacer on a sidewall of the first trench; etching the substrate through the first trench to thereby form a second trench under the first trench; performing a thermal oxidation process, using the spacer as a protection layer, to oxidize the substrate within the second trench, thereby forming an oxide layer, wherein the oxide layer is only formed within the second trench and the second trench is completely filled up with the oxide layer; after forming the oxide layer within the second trench, removing the spacer to thereby expose the sidewall of the first trench; forming a liner layer on the exposed sidewall of the first trench; and performing a chemical vapor deposition process to deposit a dielectric layer that fills the first trench.