Patent ID: 9299578
Filing Date: 2016-03-29
CPC Classification: H01L

Claim Text:
1. A method for fabricating a semiconductor device comprising: forming a first film on a base layer; forming a first mask pattern on the first film, the first mask pattern having first mask portions and sidewalls, wherein a width of each of the first mask portions and a space between adjacent first mask portions are the same; forming first sidewall films on the sidewalls of the first mask pattern by etch back of a deposited second film, each of the first sidewall films comprising a vertical side surface and a curved side surface; removing the first mask pattern; forming second sidewall films by etchback of a deposited third film on the first sidewall films, the second sidewall films comprising first portions adjacent to the vertical side surfaces and second portions adjacent to the curved side surfaces of the first sidewall films; wherein the first portions of the second sidewall films have a width of one-quarter the width of each first mask portion, and wherein the first sidewall films and the second sidewall films define portions of a second mask pattern.