Laser trim protection process and structure
US4272775A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 1979 |
| Grant date | Jun 9, 1981 |
| Priority date | — |
| Expiry date | Jun 4, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/033
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An element of an integrated circuit, such as an ion implanted region or a metal layer, may be laser trimmed without exposing P-N junctions or other circuit elements not to be trimmed to damage by the laser through use of the present protection process and structure. In the process, an oxide through which the laser trimming is carried out is formed over a selected portion of the circuit to be trimmed by the laser. A bare layer of a metal reflective to the laser radiant energy beam, such as aluminum, gold or silver, is formed surrounding the selected portion of the circuit. The selected portion of the integrated circuit is then trimmed with the laser. The oxide promotes trimming in the selected area by absorbing the laser radiant energy beam. The bare metal layer protects the portion of the integrated circuit underlying it by reflecting most of its energy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.