Design and fabricate Mosfet Masks at KUKUM Microfabrication Cleanroom for teaching undergraduates

Abstract

In teaching undergraduates program in MOSFET fabrication, mask set is one of the major problem since the cost is extensively high. The purpose of these masks is to define certain region on a wafer. In this work, a low cost mask set is fabricated with a simple technology. An economical solution of mask sets using transparency films with various channel lengths from 250um to 20 um was produced. Four mask sets of MOSFET were designed using AutoCAD 2002 drawing tools and then printed on the transparency film. Contact printing method was utilized to transfer the mask layouts onto a 4-inch silicon wafer using standard photolithography techniques to check the line uniformity. This task was done in KUKUM Microfabrication Cleanroom. The detail flow of mask making and the resist pattern on the wafer are also presented in this paper. Optical observation shows that the mask layouts were successfully transferred onto photoresist with minimum variation. Our mask sets were really cost effective and practical for teaching undergraduates purposes.