| CPC H01J 37/32642 (2013.01) [H01L 21/02019 (2013.01); H01L 21/3065 (2013.01); H01L 21/68721 (2013.01); H01L 21/68742 (2013.01)] | 20 Claims |

|
1. A method for fabricating a semiconductor structure, comprising:
placing a wafer on a chuck, wherein the wafer is surrounded by a focus ring, the focus ring is supported by a first actuator, wherein the first actuator is in a cavity defined by the chuck and an edge ring, wherein the first actuator comprises:
an outer ring disposed in the cavity, wherein the outer ring is fixed to the edge ring, and a chamber is defined in the outer ring;
a piezoelectric layer apart from a top surface of the cavity, wherein an edge of the piezoelectric layer is fixed by the outer ring; and
an inner ring disposed in the chamber at a center portion of the piezoelectric layer, wherein the inner ring overlaps with the focus ring from a top view perspective;
performing plasma etch on a surface of the wafer; and
controlling a distance between a gas distribution plate (GDP) and a top surface of the focus ring to be less than a threshold value by the first actuator.
|