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Patent US4945204A successfully refreshed from Google Patents.
US4945204A
Expired / Lapsed
US
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Method of laser-marking semiconductor devices
Assignee: Mitsubishi Electric Corp
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Filing: 1989-10-19
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Granted: 1990-07-31
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Expires: 2009-10-19
Abstract
Abstract The surface of the resin on a semiconductor device is subjected to a marking by a pulsed laser having an energy density of 3 to 60 J/cm 2 and a pulse width of 0.1 ms or less. By applying the laser beam to the surface a resin encapsulation, the resin can be instantaneously burnt and vaporized, as a result of which, the quantity of the cinders from burning of the resin at the time of the laser-marking is reduced.
Inventors
- 👤 Masakatsu Nakamura
- 👤 Sayuki Hieda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:52
CPC Classifications
H; H10; H10W; H10W46/00; B; B41; B41M; B41M5/00; B41M5/24; H10W46/601
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
110 words
A method of laser-marking semiconductor devices comprising rectifying a pulsed laser beam to substantially the same size as that of a mask engraved with a mark such as a character or the like, passing the laser beam through said mask so that the beam takes the shape of said mark, and applying said laser beam to a resin surface of a resin sealed semiconductor device to engrave the resin with said mark, wherein the energy density of said laser beam on the surface of said resin is 3 to 60 J/cm 2 ; the pulse width of said laser beam is 0.1 ms or less, whereby said marking is performed
Claim 2
Independent Claim
110 words
A method of laser-marking semiconductor devices comprising rectifying a pulsed laser beam to substantially the same size as that of a mask engraved with a mark such as a character or the like, passing the laser beam through said mask so that the beam takes the shape of said mark, and applying said laser beam to a resin surface of a resin sealed semiconductor device to engrave the resin with said mark, wherein the energy density of said laser beam on the surface of said resin is 3 to 60 J/cm 2 ; the pulse width of said laser beam is 0.1 ms or less, whereby said marking is performed
Claim 3
Dependent Claim
17 words
A method of laser-marking semiconductor devices according to claim 1, wherein said resin comprises an epoxy resin.
Claim 4
Dependent Claim
22 words
The method of laser-marking semiconductor devices according to claim 1 wherein the diameter of the laser beam is 0.5 to 5 mm.
References Cited (Backward Citations)
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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) | 1993-07-30 | 1994-01-29 | 1994-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-30 | 1998-01-29 | 1998-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-30 | 2002-01-29 | 2002-07-31 | $7700.00 | Window Closed / Lapsed |