Patent ID: 8206506
Filing Date: 2012-06-26
Classification: H01J

Abstract:
1. A showerhead electrode for use as an upper electrode of a capacitively coupled plasma processing chamber, comprising: a circular plate having a plasma exposed surface on a lower face thereof, a mounting surface on an upper face thereof, the lower face including inner and outer steps at an outer periphery of the plate; the inner step having a smaller diameter than the outer step and the outer step being located between the inner step and the mounting surface, the outer step including a horizontal surface which extends inwardly from the outer periphery and the inner step including a horizontal surface which extends inwardly from the outer step; the mounting surface including a plurality of alignment pin recesses; the plate including process gas outlets arranged in a pattern, the gas outlets communicating with gas passages extending between the upper and lower faces; wherein the outer step includes a horizontal surface which extends inwardly from the outer periphery by a first distance, the inner step includes a horizontal surface which extends inward from the outer step by a second distance, the first distance being at least two times larger than the second distance and wherein the first and the second distances are no greater than 0.28 inch; wherein the plate has parallel upper and lower faces with a thickness between the upper and lower faces of no greater than 0.5 inch, the horizontal surface of the outer step is spaced from the upper face by a first vertical distance, the horizontal surface of the inner step is spaced from the lower face by a second vertical distance, and the horizontal surface of the outer step is separated from the horizontal surface of the inner step by a third distance, the first vertical distance being greater than the second vertical distance and the second vertical distance being greater than the third vertical distance.