Practicing the Novolac deep-UV portable conformable masking technique

Abstract

Deep-UV portable conformable masking, a double-layer resist patterning technique, combines the advantages of a noncontact submicron printing technique such as refractive projection imaging or scanning electron-beam patterning with those of deep-UV conformable printing. Feasibility studies were reported earlier.1,2 Here, the processes leading to fabrication of 1-μm MOSFET devices by e-beam and step-and-repeat optical projection printing will be presented. These include processing steps to retain or remove the top resist layer, to obtain resist image profiles suitable for liftoff or for reactive ion etching (RIE), to improve adhesion, to treat the interfacial layer between the two resists, to prevent cracking, and to monitor the development of the two resist layers. Electrical testing results on pin hole density are given, followed by uncapped and capped resist images of 1-μm double-poly-Si MOSFET test sites as well as 0.8-μm thick Al lifted-off images.