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US 4,066,485 AGranted
Method of fabricating a semiconductor device
AssigneeRCA Corporation
InventorsWojciech Rosnowski, Richard Denning
Life of this patent
Estimating the term…
Abstract
A method of fabricating a semiconductor device comprises steps for forming recesses which can be used in the subsequent visual alignment of photomasks. The novel recess forming steps are so linked with a conventional processing step that the total number of steps required for the formation of the recesses is reduced. The present method is particularly adaptable to the fabrication of unisurface silicon controlled rectifiers wherein a doped isolation-type grid is formed to define each device.
Claims6
A method of fabricating a semiconductor device comprising the steps of:
- heating, in an ambient containing oxygen, a body of silicon having a layer of aluminum on a portion of a surface thereof to a temperature whereat said aluminum diffuses into said body and maintaining said body at said temperature for a preselected period of time, whereby said aluminum diffuses into said body and simultaneously forms an aluminum/silicon alloy on said portion of said surface, said aluminum/silicon alloy having a cap of aluminum oxide thereover, the remainder of said surface having a layer of silicon dioxide simultaneously formed thereon;
- and
- treating said body with an etchant which attacks said cap, said alloy and said body at a comparatively faster rate than it attacks said layer of silicon dioxide, said treating step being carried out until recesses are formed in said body beneath said alloy, whereby a photomask can be visually aligned with said recesses.
Dependencies are inferred from the claim text.