A 3-inch p-type wafer was diced into 30X30 mm pieces using an automatic dicing saw (Disco DAD 3350). For the thinning of the needle area, AZ1505 was spin-coated again on the front side of the silicon die, as the dicing was done on the backside. The dies were thinned on the intended needle areas to approximately 250µm by lowering the saw up to the desired depth.