One or more embodiments are directed to methods of removing a sacrificial layer from semiconductor wafers during wafer processing. In at least one embodiment, the sacrificial layer is removed from a wafer during an O2 plasma etch step. In one embodiment, the sacrificial layer is poly(p-phenylene-2, 6-benzobisoxazole) (PBO) or polyimide. The O2 plasma etch step causes a residue to form on the wafer. The residue is removed by immersing the wafer a solution that is a mixture of the tetramethylammonium hydroxide (TMAH) and water.