Comparison of Isotropic Dry Etching Process using XeF2 and Anisotropic Wet Etching Process using EDP for Microhotplate Device

Zarina Tardan1 and Dr Zaini Abdul Halim2

1USM, 2CEDEC, USM

Abstract

This paper discusses the difference between isotropic dry etching process using XeF2 and anisotropic wet etching process using Ethyl Diamine Pyrocathecol (EDP). The process is a bulk-etch process necessary for obtaining a suspended structure in a microhotplate device. For the dry etching process using XeF2, the pressure of the nitrogen gas is fixed to 0 Torr, while the pressure of XeF2 is fixed to 2.5Torr. Wet etching process using EDP is conducted in a fume cupboard with 75 ml ethylene diamine, 12 g pyrocathecol, and 10 ml water. Results show that both of these processes are suitable for a microhotplate device. However, there are some differences between the wet and dry etching processes that have to be considered when etching a microhotplate device. The differences in terms of surface condition, time to obtain the suspended structure, and etch rate for each etching process are discussed in detail in this paper.