Showerhead electrode

• US 20100000683A1
• Filed: 07/07/2008
• Published: 01/07/2010
• Est. Priority Date: 07/07/2008
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: de la Llera, Anthony, Kadkhodayan, Babak, Dhindsa, Rajinder, Kellogg, Michael C.
• Granted Patent: US 8,206,506 B2
• Time in Patent Office: Days
• US Class Current: 156/345.34
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow

Abstract

A showerhead electrode includes inner and outer steps at an outer periphery thereof, the outer step cooperating with a clamp ring which mechanically attaches the electrode to a backing plate.

Claims

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 inner 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 configured to mate with an inwardly extending flange of a clamp ring and the inner step configured to mate with a portion of an outer electrode which surrounds the showerhead electrode such that an inner tapered surface of the outer electrode extends from the outer edge of the plasma exposed surface;

the mounting surface including a plurality of alignment pin recesses configured to receive alignment pins arranged in a pattern matching alignment pin holes in a backing plate against which the plate is held by the clamp ring;

the plate including process gas outlets arranged in a pattern matching gas supply holes in the backing plate, the gas outlets communicating with gas passages extending between the upper and lower faces.

2. The electrode of claim 1, wherein the alignment pin recesses include a center pin recess, at least one intermediate pin recess on opposite sides of the center pin recess, and a plurality of pin recesses circumferentially spaced apart in an outer zone of the upper face overlying the inner and outer steps.

3. The electrode of claim 1, wherein the plate is of single crystal silicon.

4. The electrode of claim 1, wherein the gas outlets are arranged in a pattern of circumferential rows.

5. The electrode of claim 4, wherein the pattern of gas outlets includes 13 circumferential rows arranged in groups of 3 or 4 rows with radial distances between adjacent rows of each group smaller than radial distances separating adjacent groups of rows.

6. The electrode of claim 1, 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.

7. The electrode of claim 6, 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 upper step is separated from the horizontal surface of the lower 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.