Thermally induced reflectivity switch for laser thermal processing
US6303476A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 12, 2000 |
| Grant date | Oct 16, 2001 |
| Priority date | — |
| Expiry date | Jun 12, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/324
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method, apparatus and system for controlling the amount of heat transferred to a process region (30) of a workpiece (W) from exposure with laser radiation (10) using a thermally induced reflectivity switch layer (60). The apparatus of the invention is a film stack (6) having an absorber layer (50) deposited atop the workpiece, such as a silicon wafer. A portion of the absorber layer covers the process region. The absorber layer absorbs laser radiation and converts the absorbed radiation into heat. A reflective switch layer (60) is deposited atop the absorber layer. The reflective switch layer may comprise one or more thin film layers, and preferably includes a thermal insulator layer and a transition layer. The portion of the reflective switch layer covering the process region has a temperature that corresponds to the temperature of the process region. The reflectivity of the reflectivity switch layer changes from a low reflectivity state to a high reflectivity state at a critical temperature so as to limit the amount of radiation absorbed by the absorber layer by reflecting the incident radiation. This, in turn, limits the amount of heat transferred to the process region from th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.