What is the advantage or need for double patterning?
Double patterning refers to techniques that separate a single very dense pattern into two lower resolution patterns and printing them in separate passes. The two separate mask patterns would be aligned and interlaced to in order to produce the desired high density pattern on the actual wafer. This approach requires very precise alignment or overlay tolerances on the printing of the two masks but lowers the resolution required to print the individual masks. The need for double patterning techniques is driven by reaching the physical limits of the dimensions that can be resolved with current light sources and lenses. The equipment suppliers are working to improve overlay accuracy and wafer throughput to make double patterning economically feasible. An additional challenge to deployment of double patterning is in creating physical design layouts that can be easily split and optimized that maintain competitive area and electrical performance characteristics. Telas on-grid, single orientati
