Abstract: An apparatus for preventing plasma etching wafer clamp is disclosed in a process chamber. The apparatus comprises a pedestal, a bottom electrode, a wafer clamp, a semiconductor wafer, a quartz ring, a top electrode, a cooling plate, a anodize, and a gas hole. The wafer clamp is used to secure the semiconductor wafer. However, the wafer clamp includes a clamp ring, a concave holder, and a depression. The clamp ring is used to support the semiconductor wafer. The concave holder has a semi-elliptical surface, polymer being formed on the backside of the concave holder to prevent plasma etching in the deposition or etching process, into the clamp ring. Then The depression is designed, higher position, adjacent the concave holder.