US4793101A
Expired / Lapsed
US
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Method of making an encircling groove on the edge of a semiconductor slice of a power semiconductor component
Assignee: BBC Brown Boveri AG Switzerland
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Filing: 1987-10-15
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Granted: 1988-12-27
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Expires: 2007-10-15
Abstract
Abstract In a method of making an encircling groove (8) on the edge of a semiconductor slice (5) of a power semiconductor component, first of all the edge is surface-ground and then the groove (8) is ground in one operation by means of a form-grinding wheel (3) correspondingly contoured on the edge. An especially high output is achieved with diamond grinding wheels of appropriate grain size and suitable bond.
Inventors
- 👤 Jiri Dlouhy
- 👤 Otto Kuhn
- 👤 Andreas Ruegg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:54
CPC Classifications
B; B24; B24B; B24B9/00; B24B9/02; B24B9/06; B24B9/065; H; H10; H10P; H10P52/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
204 words
A method of making an encircling groove on an edge of a semiconductor slice of a power semiconductor component, comprising the steps of: rough grinding surplus semiconductor material from the edge of the semiconductor slice with a rough grinding wheel having diamond grains with an average diameter of 25 μm in a metal bond, with a concentration of 4.4 carats/cm 3 ; finish grinding the rough ground edge of the semiconductor slice with a precision grinding wheel having diamond grains with an average diameter of 20 μm in a synthetic bond, with a concentration of 4.4 carats/cm 2 ; grinding an encircling groove in the finish ground edge of the semiconductor slice with a form grinding wheel correspondingly contoured on an edge thereof, said form grinding wheel having diamond grains with an average diameter of 16 μm in a metal bond, with a concentration of 4.4 carats/cm 2 ; and cooling the ground edge with water having a rust preventative in all of said grinding steps, wherein all of said grinding steps are carried out at a cutting speed of 35 m/sec. with the semiconductor slice rotating at about 80 revolutions/min. and in a direction opposite to that of each respective said grinding wheel.
Claim 2
Independent Claim
204 words
A method of making an encircling groove on an edge of a semiconductor slice of a power semiconductor component, comprising the steps of: rough grinding surplus semiconductor material from the edge of the semiconductor slice with a rough grinding wheel having diamond grains with an average diameter of 25 μm in a metal bond, with a concentration of 4.4 carats/cm 3 ; finish grinding the rough ground edge of the semiconductor slice with a precision grinding wheel having diamond grains with an average diameter of 20 μm in a synthetic bond, with a concentration of 4.4 carats/cm 2 ; grinding an encircling groove in the finish ground edge of the semiconductor slice with a form grinding wheel correspondingly contoured on an edge thereof, said form grinding wheel having diamond grains with an average diameter of 16 μm in a metal bond, with a concentration of 4.4 carats/cm 2 ; and cooling the ground edge with water having a rust preventative in all of said grinding steps, wherein all of said grinding steps are carried out at a cutting speed of 35 m/sec. with the semiconductor slice rotating at about 80 revolutions/min. and in a direction opposite to that of each respective said grinding wheel.
Claim 3
Dependent Claim
20 words
The method as claimed in claim 1, wherein all of said grinding wheels are arranged on a common grinding-wheel spindle.
Claim 4
Dependent Claim
38 words
The method as claimed in claim 1, wherein the semiconductor slice, during the surface grinding step, is moved in a reciprocating manner parallel to an axis of rotation thereof and beyond the edge of the respective grinding wheel.
Claim 5
Dependent Claim
37 words
The method as claimed in claim 1, wherein the feed of the semiconductor slice toward the grinding wheels is about 3 mm/min during the rough grinding step and about 1 mm/min during the precision and groove grinding.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-27 | 1992-06-27 | 1992-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-27 | 1996-06-27 | 1996-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-27 | 2000-06-27 | 2000-12-27 | $7700.00 | Window Closed / Lapsed |