Illumination fluence regulation system and method for use in thermal processing employed in the fabrication of reduced-dimension integrated circuits
US6570656B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 10, 2000 |
| Grant date | May 27, 2003 |
| Priority date | — |
| Expiry date | Apr 10, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K2103/56
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The closed loop embodiment includes a pulsed laser controller to selectively operate a pulsed laser in a lower-power probe mode or a higher power operational mode. In lower-power probe mode, values of eT (total radiation energy flooding ICs on a silicon wafer), er (fraction of eT specularly reflected), es (fraction of eT scattered) and es (fraction of eT transmitted through wafer) are obtained. A value for ea (fraction of eT absorbed wafer) is calculated i.e. ea=eT−(er+es+et), and ea used by pulsed laser controller with pulsed laser in higher power operational mode to adjust pulsed laser fluence over the duration of a pulse to provide flooding radiation energy sufficient to melt an amorphized silicon surface layer beneath radiation-absorbent material, yet insufficient to melt crystalline silicon or ablate radiation-absorbent material. Open loop embodiment substitutes a separate low-power probe laser for operation in lower-power probe mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.