Appeal 2007-0127
Application 09/749,916
1 13. Degner describes parallel plate showerhead reactors which
2 introduce gas through the upper plate and generate etching plasma by
3 applying RF energy across the two electrodes. (col. 1, ll. 42-45).
4 14. Degner teaches that the upper electrode should not generate large
5 quantities of particles and should not release heavy metals or contamination
6 into the zone between the electrodes. (col. 1, ll.59-63).
7 15. Degner describes an electrode assembly of “semiconductor
8 purity” material having a substantially uniform thickness. (col. 2, ll. 30-32).
9 16. Degner teaches one of ordinary skill in the art to consider various
10 factors during fabrication of electrodes and to optimize impedance, current
11 capacity (for RF coupling), temperature capabilities (enduring plasma),
12 contaminant content (avoid deleterious effects on plasma), and machinability
13 (for showerhead effect) (col. 1, l. 49 - col. 2, l. 7).
14 17. Degner describes that it was conventional to use polycrystalline
15 silicon for the upper electrode plate in the known reactors (col. 2, ll. 8-12).
16 18. Degner teaches that it is “often desirable” to deliver etchant gas
17 through the upper electrode. (col. 2, ll. 2-4).
18 19. Degner describes an electrode assembly including a support frame
19 in the shape of a ring bonded to a plate. (col. 2, ll. 37-39).
20 20. Degner’s semiconductor plate is said to be “semiconductor pure”
21 and free of trace contaminants. (col. 3, ll. 50-60).
22 21. Degner’s plate can be formed from single crystal silicon. (col. 4,
23 l. 14).
24 22. Degner teaches that the thickness and other dimensions of the
25 electrodes are not critical and are selected based upon the dimensions of the
6
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