US Patent 11286565 Apparatus and method for semiconductor fabrication

An apparatus for processing a substrate is provided. The apparatus comprises a processing chamber and a showerhead. The showerhead is in the processing chamber and has a plurality of first holes with a first size in a first zone of the showerhead and a plurality of second holes with a second hole size in a second zone of the showerhead. The first hole size is different from the second hole size. The first zone is surrounded by the second zone. An area of the first zone is larger than an area of the second zone.