Electron beam direct write lithography: the versatile ally of optical lithography

Abstract

Electron beam (E-beam) direct write (EBDW) lithography is a worldwide reference technology used in laboratories, universities, and pilot line facilities for research and development. Due to its low writing speed, EBDW has never been recognized as an acceptable industrial solution, except for optical mask manufacturing. Nevertheless, its natural high-resolution capability allows for low-cost patterning of advanced or innovative devices prior to their high-volume manufacturing ramp-up. Due to its full versatility with almost all types of chemically amplified resists, EBDW is a perfect complementary solution to optical lithography. We demonstrate the compatibility of EBDW lithography with advanced negative tone development resists and the possibility of setting up a hybrid E-beam/193i lithography process flow with high performance in terms of resolution and mix and match overlay. This high-end lithography alliance offers flexibility and cost advantages for device development research and development, as well as powerful possibilities for specific applications such as circuit encryption, as discussed at the end of our study.