Patent US4247031A successfully refreshed from Google Patents.
US4247031A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for cracking and separating pellets formed on a wafer
Assignee: RCA Corp
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Filing: 1979-04-10
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Granted: 1981-01-27
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Expires: 1999-04-10
Abstract
Abstract A method for protecting electronic circuitry formed on the obverse side of a wafer from flying debris produced either by the mechanical or laser scribing or scoring of the wafer and during separation. The device is provided with a layer of abrasion resistant material on the circuit side of the wafer and the scribing or scoring is done on the obverse side of the wafer. The cracking operation is performed by applying pressure to the wafer in such a manner as to have the reverse side in tension and the obverse or circuit side in compression in order to prevent any debris which may have been cast up during the scribing or scoring operation from contaminating or damaging the circuit side of the wafer while any debris cast up during the breaking operation is thrown away from the obverse or circuit side.
Inventors
- 👤 Thomas W. Pote
- 👤 William E. Ham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:54
CPC Classifications
B; B26; B26F; B26F3/00; B26F3/002; B28; B28D; B28D5/00; B28D5/0005; B28D5/0041; B28D5/0052; Y; Y10; Y10T; Y10T225/00; Y10T225/10; Y10T225/12; Y10T225/30; Y10T225/307; Y10T225/321; Y10T225/325
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
126 words
A method of separating individual semiconductor circuit elements from a wafer on the obverse side of which the individual circuit elements were formed, the wafer being scored along lines arranged in rows and columns to define the boundary limits of the individual circuit elements comprising the steps of: applying a soft, resilient, adherent protective layer to the circuit elements on the obverse side of the wafer, the layer characterized by having the ability to return to its original form after being deformed; scoring the wafer on the reverse side thereof to define the boundary limits of the individual circuit elements; and applying a breaking force to the obverse side of the wafer to separate the individual circuit elements, one from the other, along the scored lines.
Claim 2
Independent Claim
126 words
A method of separating individual semiconductor circuit elements from a wafer on the obverse side of which the individual circuit elements were formed, the wafer being scored along lines arranged in rows and columns to define the boundary limits of the individual circuit elements comprising the steps of: applying a soft, resilient, adherent protective layer to the circuit elements on the obverse side of the wafer, the layer characterized by having the ability to return to its original form after being deformed; scoring the wafer on the reverse side thereof to define the boundary limits of the individual circuit elements; and applying a breaking force to the obverse side of the wafer to separate the individual circuit elements, one from the other, along the scored lines.
Claim 3
Dependent Claim
37 words
The method of claim 1, wherein: the wafer is selected from the group consisting of sapphire, spinel or monocrystalline aluminum oxide; and the circuit elements are formed in silicon islands on the obverse side of the wafer.
Claim 4
Dependent Claim
32 words
The method of claim 2, wherein: the breaking force is applied by means of a round, elongated mandrel; and the mandrel is forced under pressure, across the obverse side of the wafer.
Claim 5
Dependent Claim
41 words
The method of claim 3, wherein: the mandrel is first forced across the wafer in a direction parallel to the scored row lines; and the mandrel is next forced across the wafer in a direction parallel to the scored column lines.
Claim 6
Dependent Claim
85 words
The method of claim 2, comprising the further steps of: providing a mandrel with a convex hemispherical shape having a surface area at least equal to the surface area of the wafer; providing a complementary concave surface for mating with the convex hemisphere; positioning the wafer on the convex hemisphere with the scored reverse side facing the concave surface; and forcing the convex hemisphere and the concave surface into mating relationship whereby the wafer therebetween is broken into individual circuit elements along the scored lines.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-27 | 1984-07-28 | 1985-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-27 | 1988-07-28 | 1989-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-27 | 1992-07-28 | 1993-01-27 | $7700.00 | Window Closed / Lapsed |