Application of x-ray lithography with a single-layer resist process to subquartermicron large scale integrated circuit fabrication

The applicability of synchrotron radiation x-ray lithography to future ultralarge scale integrated circuit fabrication processes is demonstrated by the test fabrication of subquartermicron bipolar- complementary metaloxide semiconductor devices (SRAM, gate arrays, and several test element groups) with a total size of two-million transistors. Synchrotron radiation lithography is used at four critical levels: gate poly, first metal, via hole, and second metal. Both negative and positive chemically amplified resists are used with a single-layer resist system to simplify the resist process. An overview of the lithography process is presented with emphasis on patterning and overlay performance.