Showerhead electrode assembly for plasma processing

• US 6,170,432 B1
• Filed: 01/24/2000
• Issued: 01/09/2001
• Est. Priority Date: 01/24/2000
• Status: Expired due to Fees

• Current Assignee: MEC Technology Incorporated
• Original Assignee: MEC Technology Incorporated
• Inventors: Hadley, Trevor J., Santorelli, Mark Anthony, Szapucki, Matthew Peter, Kulkaski, Richard
• Primary Examiner(s): Mills, Gregory
• Assistant Examiner(s): HASSANZADEH, PARVIZ
• Application Number:
  US09/490,443
• Time in Patent Office: 351 Days
• Field of Search: 156/345, 118/723.E, 118/715, 118/723.R, 118/728, 118/500, 118/503, 118/726
• US Class Current: 118/723.00E
• CPC Class Codes: C23C 16/455 characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: H01J 37/3244 Gas supply means

Abstract

A showerhead electrode assembly for a plasma reactor for processing semiconductor wafers includes a gas plate having a plurality of through holes for passage of gas. The top face or side of the gas plate is of smaller diameter than the bottom side or face of the gas plate. An acutely angled peripheral groove is formed between the top face of the gas plate, and the lower portion thereof, with the groove terminating at a band-like ledge with the top face and lower portion. A locking ring is provided by two identical semicircular sections, each of which include in a lower portion of an inside sidewall, respectively, an acutely angled peripheral groove for mating with the groove of the gas plate. A unitary circular support collar is formed with a circular channel in a bottom portion thereof. These components are joined together by applying an adhesive in the channel of the support collar, mounting the locking ring sections onto the gas plate with the grooves therebetween interlocking, and thereafter forcing the channel of the support collar onto the locking ring sections until the bottom surfaces of the support collar abut against the ledge, and top face or side portion of the gas plate, respectively.

Claims

1. A showerhead electrode assembly for a plasma reactor system for processing semiconductor wafers, comprises:

a disk shaped gas plate having an upper portion of smaller diameter than a lower portion, the face of the upper portion providing a first side of said gas plate, the face of the lower portion providing a second side of gas plate, a peripheral acutely angled first groove being formed between said first side and said lower portion, said first groove terminating at a band-like ledge of said lower portion;

a locking ring including identical semicircular first and second sections each having a peripheral acutely angled second groove in a lower portion of respective inside sidewalls thereof, said second grooves being conformed to interlock with and receive said ledge with respective ends abutting, and each further including an upper portion protruding above said ledge and said first side of said gas plate;

a unitary circular support collar having opposing top and bottom portions, said bottom portion being formed with a circular channel extending into a bottom face thereof, forming a circumferential outer bottom surface on one side of said channel, and a circumferential inner bottom surface on the other side of said channel, the outer bottom surface vertically extending beyond the inner bottom surface, said channel being configured to receive the portions of said first and second sections of said locking ring protruding above said ledge and first side of said gas plate;

said support collar having its channel forced onto protruding of said first and second locking ring sections mounted on said ledge, for in turn forcing the second groove of each of said locking ring sections, respectively, to engage and interlock with the first groove of said gas plate, the outer bottom surface of said support collar abutting against said ledge, and the inner bottom surface abutting against the first side of said gas plate; and

means for rigidly securing together said first and second sections of said locking ring, and a portion of the channel of said support collar.

2. The showerhead electrode assembly of claim 1, wherein said means for rigidly securing consists of adhesive material.

3. The showerhead electrode assembly of claim 1, further including:

said channel of said support collar including an outer inside sidewall that converges or slopes inward proceeding from the opening of the channel to a bottom of said channel; and

said first and second sections of said locking ring each including an outer sidewall that slopes inward or converges proceeding from the bottom to the top of each section, and whereby the sloping sidewalls of said channel and first and second sections of said locking ring, forces said gas plate and locking ring first and second sections into a tighter interlocking fit than would otherwise be provided.

4. The showerhead electrode assembly of claim 3, wherein the slope of the outer inside sidewall of said support collar, and the slopes of said first and second sections of said locking ring are each 1°

.

5. The showerhead electrode assembly of claim 1, wherein said gas plate consists of single crystal silicon material.

6. The showerhead electrode assembly of claim 1, wherein said first and second sections of said locking ring each consist of purified graphite material.

7. The showerhead electrode assembly of claim 1, wherein said support collar consists of purified graphite material.

8. The showerhead electrode assembly of claim 1, wherein said gas plate further includes a plurality of through holes between its first and second sides for the passing of gas, said plurality of through holes being arranged in a desired pattern.

9. The showerhead electrode assembly of claim 1, wherein said gas plate further includes a plurality of through holes between its first and second sides for the passing of gas, said plurality of through holes being formed therethrough by an ultrahigh velocity water jet boring apparatus.

10. The showerhead electrode assembly of claim 1, wherein said unitary support collar further includes:

said channel being formed between an outer cylindrical wall and an inner cylindrical wall in a lower portion of said support collar;

said outer cylindrical wall having a bottom surface extending beyond a bottom surface of said inner cylindrical wall, whereby when said electrode assembly is assembled, the bottom surface of said outer cylindrical wall abuts against said ledge of said gas plate, and the bottom surface of said inner cylindrical wall abuts against said first side of said gas plate.

11. The showerhead electrode assembly of claim 10, wherein said support collar further includes an upper portion of greater outside diameter than that of said lower portion thereof.

12. The showerhead electrode assembly of claim 11, wherein said upper portion of said support collar has a greater outside diameter than the diameter of the lower portion of said gas plate.

13. The showerhead electrode assembly of claim 12, wherein the grooves of said gas plate, and said first and second sections of said locking ring each have an interior angle of 60°

.

14. The showerhead electrode assembly of claim 1, wherein the grooves of said gas plate, and said first and second sections of said locking ring each have an interior angle of 60°

.

15. The showerhead electrode assembly of claim 14, wherein the slope of the outer inside sidewall of said support collar, and the slopes of said first and second sections of said locking ring are each 1°

.

16. The showerhead electrode assembly of claim 1, wherein the slope of the outer inside sidewall of said support collar, and the slopes of said first and second sections of said locking ring are each 1°

; and

the grooves of said gas plate, and said first and second sections of said locking ring each have an interior angle of 60°

.