Application of polyimide sacrificial layers for the manufacturing of uncooled double-cantilever microbolometers

Abstract

In this paper, a low-temperature surface micromachining module with two sacrificial layers of polyimide is developed for the manufacturing of double-cantilever microbolometer focal plane arrays. The use of spin-on polyimide allows an all-dry final release step overcoming stiction problems often encountered in wet sacrificial etching processes. For the patterning of the polyimide, a plasma-enhanced chemical vapor deposited silicon oxide is employed as a mask layer. Anisotropic etching of both the mask film and the polyimide layer is accomplished by reactive ion etching. After patterning structural layers, sacrificial etching of the polyimide is conducted using an isotropic dry etch process in high-density oxygen plasma.