2.Referring to the pressure sensor of Section 4.3.1 assume that the KOH solution etches the (100) silicon at 1.4m and also etches Sio2at 7.5 nm/min. Determine the size of the backside etch mask feature that will result in a 500m diaphragm edge length on a wafer that is exactly 500m thick prior to epitaxy. How much variation in edge length is caused by a 1% variation in wafer thickness?