The effect of isopropyl alcohol on anisotropic etched silicon for the fabrication of microheater chamber

In bulk micromachining technology, anisotropic etching process has been one of the most popular processes in creating 3-dimensional MEMS structure, due to its simple and low cost process techniques. This paper presents the investigation of isopropyl alcohol (IPA) effect on anisotropic etched silicon surface of microheater chamber. The aim of the study is to find the optimal etch solution composition which will produce a smooth etched surface, low lateral etch (undercutting) effect and controllable etching rate. The etching process was carried out at with various potassium hydroxide (KOH) concentrations by adding various IPA compositions in the etchant solution. The effects of the solution were observed for several temperature conditions ranging from 50°C to 80°C. From the experimental results, it was observed that surface roughness and etch rate are highly dependent on the temperature, etchant composition and IPA concentrations in the solution. It can also be concluded that the addition of an appropriate IPA concentration provide a simple method in achieving a smooth and controlled etching of silicon substrate that plays an important factor in the fabrication of micro-heater chamber.