Fingerprint sensing device and method for manufacturing a fingerprint sensing device
First Claim
1. A capacitive fingerprint sensing device for sensing a fingerprint pattern of a finger, said capacitive fingerprint sensing device comprising:
- a protective top layer to be touched by said finger;
a first metal layer comprising a two-dimensional array of sensing structures arranged underneath said protective top layer;
a second metal layer, arranged underneath said first metal layer, comprising a plurality of conductive structures;
a dielectric layer arranged between the first and second metal layers to electrically insulate the first metal layer from the second metal layer, the dielectric layer comprising a low-k material configured to reduce a capacitive coupling between the first and second metal layer, thereby reducing capacitive crosstalk between the sensing structures and the conductive structures, wherein the dielectric constant k of the low-k material dielectric layer is in the range of 1<
k<
3.3; and
readout circuitry arranged underneath said second metal layer and coupled to each of the electrically conductive sensing structures by means of via connections to receive a sensing signal indicative of a distance between said finger and said sensing structure.
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Accused Products
Abstract
There is provided a capacitive fingerprint sensing device for sensing a fingerprint pattern of a finger, said capacitive fingerprint sensing device comprising: a protective top layer to be touched by said finger; a first metal layer comprising a two-dimensional array of sensing structures arranged underneath said top layer; a second metal layer, arranged underneath said first metal layer, comprising a plurality of conductive structures a dielectric layer arranged between the first and second metal layers to electrically insulate the first metal layer from the second metal layer, the dielectric layer comprising a low-k material; and readout circuitry arranged underneath said second metal layer and coupled to each of the electrically conductive sensing structures by means of via connections to receive a sensing signal indicative of a distance between said finger and said sensing structure. There is also provided a method for manufacturing such a device.
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Citations
14 Claims
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1. A capacitive fingerprint sensing device for sensing a fingerprint pattern of a finger, said capacitive fingerprint sensing device comprising:
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a protective top layer to be touched by said finger; a first metal layer comprising a two-dimensional array of sensing structures arranged underneath said protective top layer; a second metal layer, arranged underneath said first metal layer, comprising a plurality of conductive structures; a dielectric layer arranged between the first and second metal layers to electrically insulate the first metal layer from the second metal layer, the dielectric layer comprising a low-k material configured to reduce a capacitive coupling between the first and second metal layer, thereby reducing capacitive crosstalk between the sensing structures and the conductive structures, wherein the dielectric constant k of the low-k material dielectric layer is in the range of 1<
k<
3.3; andreadout circuitry arranged underneath said second metal layer and coupled to each of the electrically conductive sensing structures by means of via connections to receive a sensing signal indicative of a distance between said finger and said sensing structure. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for manufacturing a fingerprint sensing device, the method comprising;
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providing a substrate comprising a plurality of metal structures arranged in a metal layer on the surface of the substrate and fingerprint readout circuitry located within the substrate; providing a low-k dielectric layer covering the substrate, wherein the dielectric constant k of the low-k material dielectric layer is in the range of 1<
k<
3.3;forming via connection openings in the dielectric layer; depositing a top metal layer on the dielectric layer forming via connections such that each sensing structure is connected to corresponding readout circuitry by means of said via connections; and patterning the top metal layer to form a two dimensional array of sensing structures, wherein the low-k layer is configured to reduce a capacitive coupling between the first and second metal layer, thereby reducing capacitive crosstalk between the sensing structures and the conductive structures. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification