Masking Process and Structures Formed Thereby

摘要

A method, e.g., of forming and using a mask, includes forming an inverse mask over a dielectric layer; forming a mask layer conformally over the inverse mask; removing horizontal portions of the mask layer; and after removing the horizontal portions, simultaneously etching the inverse mask and vertical portions of the mask layer. The etching the inverse mask is at a greater rate than the etching the vertical portions of the mask layer. The etching the inverse mask removes the inverse mask, and the etching the vertical portions of the mask layer forms a mask comprising rounded surfaces distal from the dielectric layer. Recesses are formed in the dielectric layer using the mask. Locations of the inverse mask correspond to fewer than all locations of the recesses.

主权项

1. A method comprising:
forming a first mask over a dielectric layer; forming a second mask layer over and along sidewalls of the first mask; removing lateral portions of the second mask layer; after removing the lateral portions of the second mask layer, simultaneously etching the first mask and vertical portions of the second mask layer, a ratio of a rate of etching the vertical portions of the second mask layer to a rate of etching the first mask being in a range from 3:5 to 3:7, wherein etching the first mask and the vertical portions of the second mask layer removes the first mask and forms a second mask; and patterning recesses in the dielectric layer using the second mask.