Patent ID: 8026178

Claim:
A method of making a device, comprising: forming a first photoresist layer over a sacrificial layer; patterning the first photoresist layer to form first photoresist features; rendering the first photoresist features insoluble to a solvent; forming a second photoresist layer over the first photoresist features; patterning the second photoresist layer to form second photoresist features; forming a spacer layer over the first and second photoresist features; etching the spacer layer to form spacer features and to expose the first and second photoresist features; forming third photoresist features between the spacer features; removing the spacer features; patterning the sacrificial layer using the first, second and third photoresist features as a mask to form sacrificial features; forming an insulating filler layer between the sacrificial features; and removing the sacrificial features to form openings in the insulating filler layer.