Patent ID: 11887851
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 14:
15. A method of forming a semiconductor device, the method comprising:
forming a film stack over a target layer, the target layer being on a substrate;
forming a photoresist over the film stack, the photoresist comprising a bottom layer, a middle layer over the bottom layer, and a top layer over the middle layer;
patterning the top layer, wherein the patterning the top layer forms first openings through the patterned top layer;
forming an oxide layer on exposed surfaces of the patterned top layer and over bottom surfaces of the first openings, wherein the oxide layer has a first thickness on the exposed surfaces of the patterned top layer and a second thickness over the bottom surfaces of the first openings, wherein the first thickness is greater than the second thickness;
patterning the middle layer using the patterned top layer as a mask;
patterning the bottom layer using the patterned middle layer as a mask;
patterning the film stack using the patterned bottom layer as a mask;
patterning the target layer using the patterned film stack as a mask to form second openings through the target layer; and
forming conductive features in the second openings.