Patent ID: 8609489

Claim:
A method of forming a set of substantially vertical structures, comprising: photolithographically forming a plurality of substantially identical spaced-apart photoresist features over an underlying material; the spaced-apart photoresist features being in a series, and being of substantially uniform lateral width as one another; while forming the spaced-apart photoresist features, photolithographically forming a placeholder over the underlying material adjacent an end of said series; the placeholder being spaced from the end of the series of spaced-apart photoresist features by a gap, and having a lateral width that is no more than three-times the substantially uniform width of the spaced-apart photoresist features; forming an overlying material over and between the spaced-apart photoresist features, over the placeholder, and within the gap between the placeholder and the end of the series of spaced-apart photoresist features; anisotropically etching the overlying material into a plurality of first vertical structures along sidewalls of the spaced-apart photoresist features, and into a second vertical structure along a sidewall of the placeholder; covering the second vertical structure with a mask while leaving the first vertical structures uncovered; and etching into the underlying material while using the mask and the first vertical structures to define a pattern that is to be transferred into the underlying material.