Integrated circuit fabrication is still widely carried out by transporting the substrates between individual pieces of equipment in a "cleanroom" environment. Since it is impossible to fully control the contaminant content of the air, there is ample opportunity for particulates or vapors to impinge on the materials being processed, thereby altering device characteristics and reducing product yield. A complete fabrication process, including product transfer, carried out under vacuum would result in a significant reduction of substrate contamination. Many process steps may be carried out under vacuum or at reduced pressure but one critical operation, namely lithography, may not. This is currently a barrier to the realization of all-vacuum processing. The objective of this program is to investigate As-S/Ag resist system deposition, exposure (optical and electron-beam), develop, and strip, under vacuum conditions to create a lithographical process which may ultimately be used in all-vacuum applications. Extensive microfabrication facilities will be used including equipment for evaporation and sputtering, direct step on wafer and contact exposure, high resolution e-beam lithography, parallel plate and reactive ion etching, and materials analysis by EDXA, WDS, and AES. The resulting high resolution process will be compatible with multiple exposure methods under vacuum and will allow considerable progress to be made in all-vacuum processing.
