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Method for protecting chip corners in wet chemical etching of wafers

Patent ·
OSTI ID:869158
 [1]
  1. Campbell, CA
+ Show Author Affiliations

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.

Research Organization:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA
DOE Contract Number:
W-7405-ENG-48
Assignee:
Regents of University of California (Oakland, CA)
Patent Number(s):
US 5286343
OSTI ID:
869158
Country of Publication:
United States
Language:
English

References (5)

Compensating corner undercutting in anisotropic etching of (100) silicon journal June 1989
Corner compensation techniques in anisotropic etching of conference January 1991
Mesa structure formation using potassium hydroxide and ethylene diamine based etchants conference January 1988
Fabrication of Non‐Underetched Convex Corners in Anisotropic Etching of (100)‐Silicon in Aqueous  KOH  with Respect to Novel Micromechanic Elements journal December 1990
Silicon as a mechanical material journal May 1982

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/216/156/
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