Wafer shielding for prevention of lipseal plate-out

Abstract

Undesired deposition of metals on a lipseal (lipseal plate-out) during electrodeposition of metals on semiconductor substrates is minimized or eliminated by minimizing or eliminating ionic current directed at a lipseal. For example, electrodeposition can be conducted such as to avoid contact of a lipseal with a cathodically biased conductive material on the semiconductor substrate during the course of electroplating. This can be accomplished by shielding a small selected zone proximate the lipseal to suppress electrodeposition of metal proximate the lipseal, and to avoid contact of metal with a lipseal. In some embodiments shielding is accomplished by sequentially using lipseals of different inner diameters during electroplating of metals into through-resist features, where a lipseal having a smaller diameter is used during a first electroplating step and serves as a shield blocking electrodeposition in a selected zone. In a second electroplating step, a lipseal of a larger inner diameter is used.