Investigation of ProTEX PSB Thin Film as Photosensitive Layer for MEMS capacitive pressure sensor diaphragm based Si/SiC Wafer

Abstract

Characterization of ProTEXSB thin films of newly developed photosensitive layer as alternative replacement for silicon nitride or silicon oxide wet etch masks. ProTEXSB thin films have been deposited on Si/SiC wafer for bulk micromachining technology in MEMS capacitive pressure sensor diaphragm to obtain a new recipe process flow of various factor. In this paper, we will discuss the process flow for ProTEXSB deposition to estimate the final film thickness that is defined by the spin-coating rotational speed, final cure temperature and hard bake time of ProTEXSB coatings. ProTEXSB thin films have been preliminary characterized by infinite focus microscopy (IFM) and scanning electron microscopy (SEM) to examine the substrate surface conditions and the effects of undercut edges structure. Based on these results, it was determined the optimum thickness of ProTEXSB is 2.133 孠with the spin speed of 3000 rpm. The recommended for the first bake temperature of 110 àin 120 seconds and for the second bake temperature of 240 àin 60 seconds. ProTEXSB can withstand the etch mask with etch rate of 1.28 孯min for 8 hours and gives good quality effect of undercut edge on Si/SiC wafer.