APPENDIX C: Recommended Practices for Specifying RequirementsThis appendix is a recommended practice for (specifying) Oxalic acid anodic coatings for critical Etch chamber components; final call-out shall be per Applied Materials drawings:A1. When the component to be anodized has no blind holes, through holes, threaded inserts or dowel pins:FINISH: OXALIC ACID ANODIZE PER APPLIED MATERIALS SPECIFICATION 0250-34212 TO THICKNESS 0.00XX 0.00YY INCH. ALL DIMENSIONS APPLY AFTER FINISH.A2. When the component to be anodized has at least one of the following features: blind holes, through holes, threaded inserts and/or dowel pins:FINISH: OXALIC ACID ANODIZE PER APPLIED MATERIALS SPECIFICATION 0250-34212 TO THICKNESS 0.00XX 0.00YY INCH. ALL DIMENSIONS APPLY AFTER FINISHING. UNLESS OTHER WISE SPECIFIED, ALL THREADED HOLES PLUGGED OR MASKED. INSTALL THREADED INSERTS AND/OR DOWEL PINS AFTER FINISHING.A3. Default oxalic acid anodic coatings shall be Hot DI water sealed. Specify DI water sealing as follows: “Hot DI WATER SEAL PER APPLIED MATERIALS SPECIFICATION 0250-34212.”A4. Surfaces not to be anodized shall be indicated on drawings.A5. The requirements specified in Section 3.5 are not applicable to holes for threaded inserts and dowel pins. Masking or plugging of all such holes is mandatory unless otherwise indicated.A6. For oxalic acid anodic coatings on 6061 aluminum alloys, the typical thickness used in critical chamber components at Applied Materials is 0.0011 0.0002 inches.A7. Anodic coatings tend to develop voids and cracks at sharp corners and edges due to the manner of coating formation. All edges shall be radiused prior to anodizing. Chamfering shall not be applied unless resulting sharp edges are radiused. The recommended radii of curvature for various coating thickness are summarized in Table A1.A8. In some applications it may be desirable to apply oxalic acid anodic coatings to surfaces that have been textured. This specification includes requirements for both smooth surfaces (≤ 32 in Ra) and typical textured surfaces (100-140 in Ra). While oxalic acid anodic coatings may be applied to surfaces outside these texture ranges, this specification does not define performance requirements for such coatings.