Fingerprint Sensor Having ESD Protection Structure

Abstract

The invention discloses a fingerprint sensor having an ESD protection structure having multiple sensing electrode plates formed on a substrate and defining a receiving space among the sensing electrode plates; an ESD protection electrode part connected to ground and having a first conductive layer and a second conductive layer, wherein the first conductive layer is coplanar with the sensing electrode plates, and the second conductive layer is formed on the substrate and the second conductive layer has multiple conductive elements separated to each other; a dielectric layer; and a protection layer. The conductive pieces are overlapped with the first conductive layer in a vertical direction and are electrically connected to the first conductive layer through formed on the conductive layer. When the first conductive layer and / or the second conductive layer is coupled to ground, both of the first and second conductive layers provide a discharging path of static electricity.

Description

technical field [0001] The invention relates to a fingerprint sensor, in particular to a fingerprint sensor with an electrostatic protection structure. Background technique [0002] Currently, a chip-type fingerprint sensor disclosed in US Patent No. 5,325,442, please refer to Figure 9 and Figure 10 As shown, its structure mainly forms a sensing electrode layer 60 on a semiconductor substrate 80 first, and then covers the sensing electrode layer 60 with a protection layer 81 . The semiconductor substrate 80 forms a sensing integrated circuit (not shown) electrically connected to the sensing electrode layer 60, and the sensing electrode layer 60 includes a plurality of sensing electrode plates 61 arranged in a matrix. When the finger 90 touches or approaches The protective layer 81, the finger 90 and each of the sensing electrode plates 61 will form a plate capacitance Cf. Therefore, the sensing integrated circuit measures the sensing signal of each of the sensing electrod...

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Problems solved by technology

[0004] However, since the conductive grid 70 is coplanar with the plurality of sensing electrode plates 61, the distance between the finger 90 and the conductive grid 70 and the sensing electrode plates 61 is close, and excessive static electricity has no time to pass through the grounded conductive grid 70 When leaking, the sensing electrode plate 61 may be damaged, resulting in a decrease in the accuracy of fingerprint sensing

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