The Effect of Etchant Concentration and Temperature on Surface Finish of Silicon Wafer Thinning
Fabrication of silicon (Si) wafer microfilters via focus ion beam (FIB) sputtering (milling/drilling) is planned. However, due to limitations of FIB sputtering, the wafer has to be initially thinned to a certain thickness to ensure that micron-scale through holes can be successfully manufactured. This paper reports on thinning of a silicon wafer via wet chemical etching using 15, 20, and 25% w/w potassium hydroxide (KOH) at 3 different etchant temperatures (80oC, 90oC, and 100oC). The target is to achieve 100 μm with the lowest time taken and wafer surface roughness after etching. From the experiments conducted, it was determined that KOH solution at 15% w/w concentration at 100oC produced the best result with an etch rate of 5.43 μm/min, surface roughness (Ra) of 0.12μm and thickness of 123.00μm.
Iskandar I. Yaacob, Mohammad Yeakub Ali, Iis Sopyan and Saleem Hashmi
M.A. Safaruddin et al., "The Effect of Etchant Concentration and Temperature on Surface Finish of Silicon Wafer Thinning", Advanced Materials Research, Vol. 1115, pp. 29-32, 2015