US PATENT SUBCLASS 205 / 656
.~ Eroding workpiece of nonuniform internal electrical characteristics

Current as of: June, 1999
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205 /   HD   ELECTROLYSIS: PROCESSES, COMPOSITIONS USED THEREIN, AND METHODS OF PREPARING THE COMPOSITIONS

640  DF  ELECTROLYTIC EROSION OF A WORKPIECE FOR SHAPE OR SURFACE CHANGE (E.G., ETCHING, POLISHING, ETC.) (PROCESS AND ELECTROLYTE COMPOSITION) {19}
656.~ Eroding workpiece of nonuniform internal electrical characteristics

DEFINITION

Classification: 205/656

Eroding workpiece of nonuniform internal electrical characteristics:

(under subclass 640) Process in which the workpiece has electrical characteristics which vary within its interior (e.g., doped semiconductor with n and p regions, etc.), so that erosion proceeds at differing rates on one or more localized areas or portions thereof, usually to confine the erosion to desired locations.

(1) Note. The electrical nonuniformity need not be "normal," and may be brought about by processing (e.g., by short-circuiting, etc.).

SEE OR SEARCH THIS CLASS, SUBCLASS:

666+, for electrolytic erosion in which the workpiece has a distinguishable surface layer called a mask, usually having different electrical characteristics than the workpiece itself.

SEE OR SEARCH CLASS

438, Semiconductor Device Manufacturing: Process, for chemical etching of a semiconductive substrate utilizing a p-n junction as an etch stop.