Method for programming circuit elements in integrated circuits
US4387503A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 13, 1981 |
| Grant date | Jun 14, 1983 |
| Priority date | — |
| Expiry date | Aug 13, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/091
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A laser programmable logic switch (22) includes a fusible link (28), an output node (26) and a transistor (24) which is fabricated to be in the off state. When it is desired to have the output node (26) at a low logic state, the circuit (22) is left unchanged. But if it is determined that the output node (26) should be at a high logic level state, the fusible link (28) is opened by a first laser pulse. A second laser pulse is then applied to transistor (24) to cause damage to the structure of the transistor (24). The transistor (24) can be damaged in any of a number of modes which result in the formation of a conducting path between the output node (26) and the power terminal V.sub.cc. Unlike conventional laser switch circuits, the circuit (22) does not draw static power under any conditions thereby reducing power consumption by the integrated circuit utilizing such a laser switched gate. In a further embodiment a single transistor (90) fabricated in a nonconducting state is connected between first and second nodes (92, 94) but when damaged by a laser pulse the transistor (90) provides a low impedance connection between the nodes (92, 94). In a still further embodiment a transfer (…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.