Patent ID: 8394724

Claim:
A method for forming a device comprising: providing a substrate prepared with a device layer formed thereon; providing a mask layer above the device layer; patterning the mask layer to produce a first pattern; partially trimming the mask layer with the first pattern selectively to reduce a dimension of the first pattern to produce a trimmed mask with a second pattern with a reduced dimension, wherein the reduced dimension of the second pattern is an intermediate dimension larger than a desired dimension of a device feature, and comprises partially trimming the mask layer up to about 20-30% of a gap dimension, wherein the gap dimension is the difference between a ground rule and the desired dimension of the device feature; and patterning the device layer with the trimmed mask layer using an etch comprises first and second patterning chemistries to form the device feature, wherein the first patterning chemistry comprises SF 6 , C 2 F 6 or CF 4 , and the second patterning chemistry comprises CH 2 F 2 or C 4 F 8 , the etch patterns the device layer and trims the device layer to form the device feature with the desired dimension which is smaller than the reduced dimension of the trimmed mask over the device feature, the trimming results in a reduced line end shortening (LES) ratio, wherein the LES ratio is about 1.1 to 1.2.