PATENT COVER GRAPHIC


United States Patent 3,537,921
November 3, 1970

Selective Hydrofluoric Acid Etching And Subsequent Processing
Bernard W. Boland

Filed February 28,1967
Image of US PATENT 3,537,921

Abstract of the Disclosure

A process for selectively etching silicon nitride, chromium, ultra thin silicon dioxide, etc. layers using a thin layer of silicon as a mask against hydrofluoric acid (HF) etchants. Then long diffusions, using indium, gallium, etc. are performed through a selectively etched silicon nitride mask into an underlying semiconductor without mask reprocessing cycles
Figure descriptions: cover graphic

  • Figure 1 is a flow chart illustrating a method embodying the present invention
  • Figure 2 is a series of schematic cross-sectional views aligned with the Figure 1 steps to illustrate a structure which may be expected when practicing the method of this invention.
  • Figure 3 shows an additional semiconductor structure made according to the methods of this invention.

 Citations [54]:
  
2,583,681 01/1952 Brittain et al. 3,193,418 07/1965 Cooper et al. 3,438,873 04/1969 Schmidt
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