3G/4G requirements for wireless systems and the role GaAs, GaN and filter devices will play in meeting these requirements

Otto Berger, TriQuint Semiconductor, Konrad‐Zuse‐Platz 1, D‐81829 Munich, Germany

Abstract
A common photolithography requirement is to generate a slope in a developed resist pattern prior to etch. To generate the sloped profile the resist is either exposed out of focus, hard baked after develop to flow the resist, or eroded as part of the subsequent etch process. Each of these options requires control of multiple processes to generate a slope that is uniform across the wafer, between wafers and between lots.
In this feasibility study, Skyworks evaluated one new approach that uses mask features below the resolution limit of the stepper to expose away part of the resist around the edges of designed features.

Paper 8a.1.pdf