I am looking for a protective coating or tape to stand up to KOH for an extended period. At the end of the etch my wafers are thin. I am mostly concerned with the outer rim of the wafer, where even small scratches become great cleavage planes. I realize that there are a couple commercially available coatings, such as Protec or BPR100. Does anyone know which ones are better for long processing? Also, I am etching my wafer on both sides, so I can't spin on a protective coating. I wonder if I can simply paint the edge of the wafer with these coatings and then bake them. Will they still be resistant to KOH? Are there any other products or ideas that I should consider? Thank you, Arthur Beyder SUNY at Buffalo