Methods for controlling line dimensions in spacer alignment double patterning semiconductor processing

摘要

Methods for forming uniformly spaced and uniformly shaped fine lines in semiconductor processes using double patterning. Dummy lines are formed over a substrate. Sidewall spacer material is deposited over the top and sides of each of the dummy lines. Etching is performed to remove the top surface sidewall spacer material from the tops of the dummy lines. The dummy material is removed by selective etching leaving the spacer material. A photolithographic mask is formed defining inner lines that are desired for a substrate etching step, and temporary lines outside of the desired lines. The temporary lines are partially masked. The temporary lines are partially removed while the inner desired lines are retained. A transfer etch process then patterns an underlying mask layer corresponding to the inner desired lines, and the mask layer is used for etching lines in an underlying semiconductor substrate.

主权项

1. A method, comprising
forming a mask layer and an underlying layer over a semiconductor substrate; forming a plurality of parallel lines in the mask layer having a line width and a line spacing distance and having a line pitch that is the sum of the width and the spacing distance; using a photolithographic process, patterning a photoresist to cover a plurality of the lines in the mask layer corresponding to desired lines, and patterning the photoresist to cover a portion of at least two temporary lines in the mask layer corresponding to temporary lines lying adjacent to the desired lines and on the outside of a plurality of desired lines, leaving a portion of the temporary lines exposed; etching the plurality of lines in the mask layer to remove a portion of each of the at least two temporary lines while retaining the covered portion of the at least two temporary lines; and etching the mask layer and an underlying layer using the desired lines and the temporary lines as an etch mask, removing at least a portion of the underlying layer beneath the at least two temporary lines while the portions of the underlying layer lying beneath the lines corresponding to the desired lines are retained.