FIR infrared (FIR) sensor with two absorption layers

Patent metadata

Field	Value
Publication number	US-12484446-B2
Application number	US-202217739780-A
Country	US
Kind code	B2
Filing date	May 9, 2022
Priority date	Jul 27, 2021
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

There is provided a far infrared (FIR) sensor device including a substrate, a thermopile structure and a heat absorption layer. The thermopile structure is arranged on the substrate. The heat absorption layer covers upon the thermopile structure, wherein the heat absorption layer has a hollow space which is formed by etching a metal layer in the heat absorption layer.

First claim

What is claimed is:

1 . A far infrared (FIR) sensor, comprising:
a substrate; a thermopile structure, arranged on the substrate; a heat absorption layer, covering upon the thermopile structure, and comprising a first heat absorption layer stacking on a second heat absorption layer, wherein the first heat absorption layer and the second heat absorption layer are connected by a connection layer, and a cross section of the connection layer is smaller than cross sections of the first heat absorption layer and the second heat absorption layer; and a peripheral circuit arranged on the substrate and the peripheral circuit comprising multiple metal layers, wherein the connection layer is aligned with one of the multiple metal layers in a transverse direction.

2 . The FIR sensor as claimed in claim 1 , wherein a width of the connection layer is smaller than 10 micrometers.

3 . The FIR sensor as claimed in claim 1 , wherein the cross section of the connection layer is smaller than 1/10 of the cross sections of the first heat absorption layer and the second heat absorption layer.

4 . The FIR sensor as claimed in claim 1 , wherein an upper surface of the first heat absorption layer is further arranged with a blocking layer as an etch stop layer.

5 . The FIR sensor as claimed in claim 4 , wherein the blocking layer is lower than a top layer among the multiple metal layers.

6 . The FIR sensor as claimed in claim 1 , wherein the thermopile structure comprises:
a first polysilicon layer and a second polysilicon layer stacked to each other, wherein the first polysilicon layer and the second polysilicon layer have different Seebeck coefficients; a dielectric layer, sandwiched between the first polysilicon layer and the second polysilicon layer; and a metal layer, connected to the first polysilicon layer and the second polysilicon layer respectively using a via.

7 . A far infrared (FIR) sensor, comprising:
a substrate; a thermopile structure, arranged on the substrate; and a heat absorption layer, covering upon the thermopile structure, and comprising a hollow space formed after a metal layer in the heat absorption layer is etched, wherein an upper surface of the heat absorption layer is further arranged with a blocking layer as an etch stop layer.

8 . The FIR sensor as claimed in claim 7 , further comprising a peripheral circuit arranged on the substrate, and the peripheral circuit comprising multiple metal layers, wherein the hollow space is aligned with one of the multiple metal layers in a transverse direction.

9 . The FIR sensor as claimed in claim 7 , further comprising a peripheral circuit arranged on the substrate, and the peripheral circuit comprising multiple metal layers, wherein the hollow space is not aligned with any one of the multiple metal layers in a transverse direction.

10 . The FIR sensor as claimed in claim 7 , further comprising a peripheral circuit arranged on the substrate, and the peripheral circuit comprising multiple metal layers, wherein the blocking layer is lower than a top layer among the multiple metal layers.

11 . A far infrared (FIR) sensor, comprising:
a substrate; a thermopile structure, arranged on the substrate; a heat absorption layer, covering upon the thermopile structure, and comprising a first heat absorption layer stacking on a second heat absorption layer, wherein the first heat absorption layer and the second heat absorption layer are connected by a connection layer, and a cross section of the connection layer is smaller than cross sections of the first heat absorption layer and the second heat absorption layer; and a peripheral circuit arranged on the substrate and the peripheral circuit comprising multiple metal layers, wherein the connection layer is not aligned with any one of the multiple metal layers in a transverse direction.

Assignees

• Pixart Imaging Inc

Inventors

• Tsai Ming-Han
• Hu Chih-Fan

Classifications

• H10N19/101

  Multiple thermocouples connected in a cascade arrangement · CPC title

• H10N10/851

  comprising inorganic compositions · CPC title

• H10N10/13

  characterised by the heat-exchanging means at the junction · CPC title

• H10N10/01

  Manufacture or treatment · CPC title

• G01J5/14 Primary

  Electrical features thereof · CPC title