| 摘要 |
In integrated circuit fabrication a method is provided involving the utilization of the same positive photoresist layer to form two different masks used in two separate etching steps. A positive photoresist layer is formed on a substrate, and portions of the positive photoresist layer are selectively exposed and developed to form the photoresist mask having a pattern of openings therethrough exposing the underlying substrate. Then, the substrate exposed in these openings is etched to form the pattern of recesses in the substrate corresponding to the openings. Next, portions of the remaining photoresist layer respectively adjacent to openings in the photoresist layer are exposed and developed to laterally expand such openings, after which the substrate exposed in these expanded openings is etched whereby the portions of the recesses underlying the original openings are etched deeper than the portions of the recesses underlying the expanded portions of said openings. The result is a two-level recess pattern. |
