An electron projection and alignment system for 3-inch diameter wafers

Summary form only given, as follows. An Electron Projection System is being developed at Radiant Energy Systems. Inc. for the purpose of providing submicron imaging and alignment in the mask alignment process. This system is the first electron beam lithography system capable of exposing 3-inch diameter wafers in seconds. The system is designed to process wafers au.tomatically once inserted into the vacuum system. Alignment of the mask to the wafer is computer controlled and requires no operator assistance. The system, called the EPS-1500 Electron Projection System, images an integrated circuit mask onto a silicon wafer utilizing a photoemissive surface and coaxial magnetic and electric fields. 3-inch wafers have been processed with micron resolution over the full 3-inch format. Multilayer alignments have been accomplished with integrated circuit mask sets. Alignment is accomplished via holes drilled in the silicon wafer. These holes provide alignment sensitivities of 0.1 micron and survive all processing steps. The performance of the system as compared to conventional mask alignment systems and other microfabrication techniques is discussed.