Fingerprint detector with scratch resistant surface and embedded ESD protection grid
US6515488B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 7, 2001 |
| Grant date | Feb 4, 2003 |
| Priority date | — |
| Expiry date | May 7, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1329
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A fingerprint detector having a smooth sensor surface for contact with a fingerprint includes capacitive sensor plates defining an array of sensor cells below the sensor surface and tungsten ESD protection grid lines surrounding each sensor cell. The sensor surface is defined by silicon carbide and includes silicon oxide filling cavities in the silicon carbide. The cavities inherently result from processing steps, including removal of the tungsten atop the silicon carbide that is used to define the grid lines. Filling the cavities with oxide and smoothing the surface using chemical mechanical polishing provides a scratch-resistant surface and improves the sensitivity of the capacitive sensor cells.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.