Patent ID: 9704746
Date: 2017-07-11
CPC Classifications: H01L

Claim:
1. A method comprising: forming an ultra low-K (ULK) layer; forming a self-aligned contact (SAC) silicon nitride (SiN) layer over the ULK layer; forming mandrels directly on the SAC SiN layer; cutting the mandrels; selectively etching the SAC SiN layer across the cut mandrels, forming first trenches; filling the first trenches with a metal oxide; forming a conformal metal oxide layer over the cut mandrels, the metal oxide, and the SAC SiN layer; removing horizontal portions of the conformal metal oxide layer over the cut mandrels and the SAC SiN layer; removing the cut mandrels; removing exposed portions of the SAC SiN layer and etching the underlying ULK layer, forming second trenches; and stripping a remainder of the metal oxide, conformal metal oxide layer, and SAC SiN layer.