Method for protecting chip corners in wet chemical etching of wafers
The present invention is a corner protection mask design that protects chip corners from undercutting during anisotropic etching of wafers. The corner protection masks abut the chip corner point and extend laterally from segments along one or both corner sides of the corner point, forming lateral extensions. The protection mask then extends from the lateral extensions, parallel to the direction of the corner side of the chip and parallel to scribe lines, thus conserving wafer space. Unmasked bomb regions strategically formed in the protection mask facilitate the break-up of the protection mask during etching. Corner protection masks are useful for chip patterns with deep grooves and either large or small chip mask areas. Auxiliary protection masks form nested concentric frames that etch from the center outward are useful for small chip mask patterns. The protection masks also form self-aligning chip mask areas. The present invention is advantageous for etching wafers with thin film windows, microfine and micromechanical structures, and for forming chip structures more elaborate than presently possible. 63 figures.
- DOE Contract Number:
- W-7405-ENG-48
- Assignee:
- Univ. of California, Oakland, CA ()
- Patent Number(s):
- US 5286343; A
- Application Number:
- PPN: US 7-918601
- OSTI ID:
- 5221413
- Resource Relation:
- Patent File Date: 24 Jul 1992
- Country of Publication:
- United States
- Language:
- English
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