Process for etching a transparent workpiece including backside endpoint detection steps
US8012366B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 30, 2006 |
| Grant date | Sep 6, 2011 |
| Priority date | — |
| Expiry date | Sep 14, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/32963
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method is provided for defining a pattern on a workpiece such as a transparent substrate or mask or a workpiece that is at least transparent within a range of optical wavelengths. The method includes defining a photoresist pattern on the top surface of the mask, the pattern including a periodic structure having a periodic spacing between elements of the structure. The method further includes placing the mask on a support pedestal in a plasma reactor chamber and generating a plasma in the chamber to etch the top surface of the mask through openings in the photoresist pattern. The method also includes transmitting light through the pedestal and through the bottom surface of the mask, while viewing through the support pedestal light reflected from the periodic structure and detecting an interference pattern in the reflected light. The method further includes determining from the interference pattern a depth to which periodic structure has been etched in the top surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.