In response to the previous post, Bob Patti of Tezzaron Semiconductors weighed in with a solution to performing under bump metallization (UBM) on conformal (lined rather than filled) TSVs. Patti says that Dr. Zhang is correct in stating that you can’t put UBM on top of a conformal TSV. However, he suggests solving the issue by placing a pad next to the TSV and putting the UBM there. Thanks for your help, Bob! – F.v.T.