Automatic impurity profiling machine
Abstract
Abstract A MACHINE AND METHOD FOR AUTOMATICALLY DETERMINING THE DISTRIBUTION OF IMPURITIES CONTAINED IN A SEMICONDUCTOR BODY. THE MACHINE IS PARTICULARLY USEFUL IN DETEMINING THE DEPTH OF VERY SHALLOW JUNCTIONS IN THE ORDER OF 1/2 MICRON AND LESS. THE MACHINE SUCESSIVELY ANODIZES THE SURFACE OF THE SEMICONDUCTOR BODY TO PRODUCE AN ANODIZED SEMICONDUTOR LAYER, REMOVES THE ANODIZED LAYER BY CHEMICAL ETCHING, MEASURES AN ELECTRICAL CHARACTERISTIC, SUCH AS A SPREADING RESISTANCE AND SHEET RESISTANCE, OF THE SEIMICONDUCTOR BODY AND RECORDS THE ELECTRICAL CHARACTERISTIC IN TERMS OF THE CHARACTERISTIC VERSUS THE AMOUNT OF MATERIAL REMOVED. THE MACHINE AUTOMATICALLY REPEATS THIS CYCLE UNTIL A RESISTIVITY PROFOLE FOR THE DESIRED DEPTH OF MATERIAL IS OBTAINED. A SHARP CHANGE WILL BE OBSERVED IN THE RECORDED PROFILE OF THE ELECTRICAL CHARACTERISTIC VERSUS THE AMOUNT OF MATERIAL REMOVED WHEN A PN JUCTION IS CROSSED.
Inventors
- 👤 Michael C Duffy
- 👤 Richard L Hudson
Bibliographic Details
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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) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |