Patent ID: 6981240
Filing Date: 2005-12-27
Classification: G03F,H01L

Abstract:
1. A method for producing a computer readable definition of a photolithographic mask that defines a pattern in a layer to be formed using the mask, wherein the pattern includes a plurality of features corresponding to a plurality of static random access memory (SRAM) cells, an SRAM cell including two T's with off-centered lines opposing each other, the method comprising: selecting at least one cutting pattern from a set of patterns including at least (i) a first cutting pattern comprising a first cut between two contact landing pads of each SRAM cell, and a second cut and a third cut on inside corners of a T of each SRAM cell opposite the first cut, (ii) a second cutting pattern comprising a first cut between two contact landing pads of each SRAM cell and a second cut on the back of the T of each SRAM cell to the back of the T of an adjacent SRAM cell, (iii) a third cutting pattern comprising a first cut and second cut from contact landing pads of the SRAM cell to a field area of the SRAM cell and a third cut on the back of the T of the SRAM cell to the back of the T of an adjacent SRAM, and (iv) a fourth cutting pattern comprising a first cut and a second cut in opposing inside corners of the T of each SRAM cell to a contact corner for use in defining the plurality of SRAM cells; and defining a plurality of shifters in the computer readable definition of the mask to substantially fully define the plurality of SRAM cells using destructive light interference, the plurality of shifters being separated by cuts according to the cutting pattern.