Patent ID: 8987112
Filing Date: 2015-03-24
Classification: H01L

Abstract:
1. A method for fabricating a semiconductor device, comprising: forming a first well and a second well having a different impurity doping concentration on a substrate; etching the substrate to form a trench in a boundary region in which the first well and the second well are in contact with each other such that a first side of the trench is disposed in the first well and a second side of the trench is disposed in the second well; forming a sacrificial pattern to cover the first side of the trench without covering the second side of the trench; etching an exposed bottom surface of the second side of the trench by using the sacrificial pattern as an etch barrier; removing the sacrificial pattern; and filling the trench with an insulation material to form an isolation layer having two different depths with respect to a top surface of the substrate.