US3715423A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plastic encapsulation of semiconductor devices
Assignee: Motorola Solutions Inc
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Filing: 1971-01-25
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Granted: 1973-02-06
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Expires: 1991-01-25
Abstract
Abstract A first plastic encapsulated subassembly has a cup-shaped recess with the sides of the cup having a taper of about 30* and a heat sink opposite the cup. The assembly is placed in a cavity of a mold with a second heat sink in contact with the subassembly heat sink and resting on one face of the mold cavity. A mold pin is inserted into the cup-shaped recess, forcing the subassembly, using a precalculated and controlled deformation of the cup, heat sink and the one mold face together such that the later injected plastic encapsulating material does not flow therebetween to provide a good thermal path from the subassembly heat sink to an outer face of the completed plastic encapsulated assembly.
Inventors
- 👤 T Dunn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:34
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/14; B29C45/14639; B29C45/14655; B29C70/00; B29C70/68; B29C70/72; H; H10; H10W; H10W74/00; H10W74/01; H10W74/016; B29L; B29L2031/00; B29L2031/34; B29L2031/3406
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
240 words
A method for the plastic encapsulation in a mold cavity of an electrical unit including at least one sub-assembly containing a semiconductor element comprising the following steps: a. encapsulating in plastic a sub-assembly containing a semiconductor element to provide an exposed metal surface, b. forming a conical recess in the plastic portion of said sub-assembly opposite to said exposed metal surface, c. placing a metal member inside the mold cavity, d. placing the encapsulated sub-assembly into the mold cavity and orienting said sub-assembly so that said metal member is interposed between the metal surface of said sub-assembly and an inner wall of the mold cavity, e. closing the mold cavity, f. inserting a mold pin into said cavity to enter said conical recess of the encapsulated sub-assembly, said plastic portion being located on an opposing surface of the sub-assembly with respect to the exposed metal surface thereof, g. applying a force to said mold pin sufficient to deform the sides of said recess without breaking said subassembly and urge the combination of said exposed metal surface, said metal member and the adjacent wall of said mold cavity into sealing engagement, h. inserting plastic encapsulating material into said mold cavity while maintaining the force on said mold pin, and then i. removing the plastic encapsulated electrical unit from the mold cavity, said encapsulated unit having an external metal member in contact with said exposed metal surface of the sub-assembly contained therein.
Claim 2
Independent Claim
240 words
A method for the plastic encapsulation in a mold cavity of an electrical unit including at least one sub-assembly containing a semiconductor element comprising the following steps: a. encapsulating in plastic a sub-assembly containing a semiconductor element to provide an exposed metal surface, b. forming a conical recess in the plastic portion of said sub-assembly opposite to said exposed metal surface, c. placing a metal member inside the mold cavity, d. placing the encapsulated sub-assembly into the mold cavity and orienting said sub-assembly so that said metal member is interposed between the metal surface of said sub-assembly and an inner wall of the mold cavity, e. closing the mold cavity, f. inserting a mold pin into said cavity to enter said conical recess of the encapsulated sub-assembly, said plastic portion being located on an opposing surface of the sub-assembly with respect to the exposed metal surface thereof, g. applying a force to said mold pin sufficient to deform the sides of said recess without breaking said subassembly and urge the combination of said exposed metal surface, said metal member and the adjacent wall of said mold cavity into sealing engagement, h. inserting plastic encapsulating material into said mold cavity while maintaining the force on said mold pin, and then i. removing the plastic encapsulated electrical unit from the mold cavity, said encapsulated unit having an external metal member in contact with said exposed metal surface of the sub-assembly contained therein.
Claim 3
Dependent Claim
21 words
The method in accordance with claim 1 wherein said deforming of the sides of said conical recess is the scraping thereof.
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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) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |