FINGERPRINT DETECTOR WITH SCRATCH RESISTANT SURFACE EMBEDDED ESD PROTECTING GRID

摘要

PROBLEM TO BE SOLVED: To improve the durability and reliability of a fingerprint detector.;SOLUTION: The 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 the removal of tungsten atop the silicon carbide that is used to define the grid lines. The cavities are filled with the oxide, and the surface made smooth by using chemical mechanical polishing, thus a scratch resistant surface is provided and the sensitivity of the capacitive sensor cells is improved.;COPYRIGHT: (C)2003,JPO