United States Patent 3,990,925
November 9, 1976

Removal Of Projections On Expitaxial Layers
William Charles Erdman

Filed March 31, 1975
Image of US PATENT 3,990,925

Abstract of the Disclosure

A method for removing projections from the surface of epitaxially-deposited semiconductor layers is described. These projections can adversely affect the results of photolithographic processing. The method comprises forming an oxide layer on the surface and mechanically fracturing the oxide-coated projections. In the ensuing step anisotropic semiconductor etchants are applied to the surface to remove the projections selectively.
Figure descriptions: cover graphic

  • schematically represents a cross section of the wafer during one step of one embodiment in accordance with the invention.

 Citations [54]:
3,699,644 10/1972 Cocca 3,718,514 02/1973 Erdman et al 3,738,881 06/1973 Erdman et al 3,783,044 01/1974 Cheskis et al 3,838,501 10/1974 Umbaugh et al
National Museum of American History
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