| US 7,544,521 B1 | ||
| Negative bias critical dimension trim | ||
| Scott Briggs, Menlo Park, Calif. (US); and Aaron Eppler, Fremont, Calif. (US) | ||
| Assigned to Lam Research Corporation, Fremont, Calif. (US) | ||
| Filed on Sep. 11, 2006, as Appl. No. 11/519,384. | ||
| Int. Cl. H01L 21/311 (2006.01); H01L 21/66 (2006.01) | ||
| U.S. Cl. 438—9 [438/587; 430/30; 257/E21.027; 257/E21.039; 257/E21.36] | 12 Claims |
| 1. A method of etching an etch layer of an inorganic material, comprising:
forming a mask of an organic material over the etch layer wherein the mask has at least a first region with a first density
and a second region with a second density;
measuring a surface area of the organic material in the first region;
measuring a surface area of the organic material in the second region;
using the measured surface area of the organic material in the first region and the measured surface area of the organic material
in the second region to determine requirements for a reverse bias trim of the mask; and
providing a reverse bias trim of the mask, wherein a ratio of a trim rate of the organic material in the first region to a
trim rate of the organic material in the second region is related to a ratio of the measured surface area of the organic material
in the first region to the measured surface area of the organic material in the second region.
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