Fabrication of high performance 512Kb SRAMs in 0.25 μm CMOS technology using x-ray lithography

Fully functional 512Kb static-random access memory (SRAM) devices containing more than 3.6 million transistors have been successfully fabricated in a 0.25 μm complementary metal oxide semiconductor (CMOS) technology using compact storage ring X-ray lithography thus demonstrating the functionality of the X-ray lithography infrastructure. A lithographic performance comparison was made between x-ray lithography and optical (excimer laser) lithography by fabricating SRAM devices using both lithographic techniques. The excellent process latitude and dimension control available for x-ray lithography is reflected in this comparison. A comprehensive discussion of the advantages of x-ray lithography is discussed in this paper. © 1994.