Thermoelectric sensor for fingerprint thermal imaging
First Claim
1. A fingerprint sensor chip which is used to read a ridge pattern of a fingerprint designed and manufactured using CMOS integrated circuits processing, said fingerprint sensor chip comprising:
- a plurality of thermoelectric sensors arranged in a two-dimensional array and integrates its signal processing circuits on a single chip, which utilizes body temperature of a human being as a stimulation source for biometrics, whereby a temperature gradient is produced from a ridge of a fingerprint contacting said thermoelectric sensor and converts the temperature gradient into an electrical signal.
2 Assignments
0 Petitions
Accused Products
Abstract
The present invention provides a fingerprint sensing mechanism using a two-dimensional thermoelectric sensor array to capture the thermal image related to the ridges and valleys on the finger, wherein its fabricating method is totally compatible with integrated circuits processing. Using the body temperature of a human being as the stimulation source for biometrics, a temperature difference is produced from a ridge of a fingerprint contacting the thermoelectric sensor and the temperature gradient is converted into an electrical signal. A plurality of thermoelectric sensors arranged in a two-dimensional array forms a fingerprint sensor so as to obtain the electrical signal output of the ridge profile of the fingerprint.
49 Citations
9 Claims
-
1. A fingerprint sensor chip which is used to read a ridge pattern of a fingerprint designed and manufactured using CMOS integrated circuits processing, said fingerprint sensor chip comprising:
a plurality of thermoelectric sensors arranged in a two-dimensional array and integrates its signal processing circuits on a single chip, which utilizes body temperature of a human being as a stimulation source for biometrics, whereby a temperature gradient is produced from a ridge of a fingerprint contacting said thermoelectric sensor and converts the temperature gradient into an electrical signal. - View Dependent Claims (2, 3, 4, 5, 6)
-
7. A CMOS thermoelectric sensor comprising at least a polysilicon layer and at least two interconnection layers, said thermoelectric sensor comprising following elements:
-
a silicon substrate;
a thermo-isolation structure defined on said silicon substrate, wherein said thermo-isolation structure is defined by utilizing a field oxide layer or a trench isolation layer;
a thin oxide layer formed surrounding said thermo-isolation structure, wherein said thin oxide layer is used as a gate oxide layer;
at least a thermocouple composing of a first thermocouple material and a second thermocouple material, wherein a hot-junction region of said thermopile is located at a central portion of said field oxide layer and a cold-junction region is located on a thin oxide layer which is surrounding said field oxide layer;
at least a via hole metal to connect said first thermocouple material and said second thermocouple material; and
a heat pipe structure comprising at least an interconnection layer and at least a via hole metal plug, wherein said heat pipe structure is located between said central portion of said field oxide layer and a passivation layer which is on a surface of said substrate. - View Dependent Claims (8, 9)
-
Specification