Infrared sensor and infrared solid-state image pickup apparatus

• US 10,274,374 B2
• Filed: 11/13/2017
• Issued: 04/30/2019
• Est. Priority Date: 05/24/2017
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Sugino, Takaki, Shintani, Kenji, Misaki, Koji
• Primary Examiner(s): Green, Yara B
• Application Number:
  US15/810,369
• Publication Number:
  US 20180340836A1
• Time in Patent Office: 533 Days
• Field of Search: 2503381
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 2005/202 Arrays
• CPC Class Codes: G01J 5/023 Particular leg structure or construction or shape; Nanotubes
• CPC Class Codes: G01J 5/024 Special manufacturing steps or sacrificial layers or layer structures
• CPC Class Codes: G01J 5/06 Arrangements for eliminating effects of disturbing radiation; Arrangements for compensating changes in sensitivity for adjusting of solid angle of collected radiation G01J5/07; means for wavelength selection G01J5/0801
• CPC Class Codes: G01J 5/10 using electric radiation detectors
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices

Abstract

An infrared sensor includes an infrared sensor pixel in which a contact hole is formed to electrically connect a metal wiring layer and a support leg metal wiring layer that is located inside a support leg. The metal wiring layer is electrically connected to a signal reading circuit. The contact hole is formed by etching an insulating layer that is formed by deposition so as to cover the metal wiring layer, and has a bottom portion and a side wall portion that are each shaped into a forward tapered shape.

Claims

1. An infrared sensor, comprising an infrared sensor pixel in which a contact hole is formed to electrically connect a metal wiring layer and a support leg metal wiring layer, the metal wiring layer being electrically connected to a signal reading circuit, the support leg metal wiring layer being located inside a support leg,

wherein the contact hole is formed by etching an insulating layer that is formed by deposition so as to cover the metal wiring layer, and

wherein the contact hole has a bottom portion and a side wall portion that are each shaped into a forward tapered shape,

wherein the support leg metal wiring layer extends through the contact hole and parallel to the bottom portion and the side wall portion that are each shaped into the forward tapered shape.

2. The infrared sensor according to claim 1, wherein the side wall portion of the contact hole is given the forward tapered shape by forming a side wall that has a forward tapered shape on an inner side surface of the insulating layer after the etching.

3. The infrared sensor according to claim 1, wherein the bottom portion of the contact hole is given the forward tapered shape by forming a forward tapered portion in an upper portion of the metal wiring layer in the etching.

4. The infrared sensor according to claim 1,

wherein the contact hole is formed by etching the insulating layer that is formed by deposition so as to cover an anti-reflection layer in addition to the metal wiring layer, the anti-reflection layer being formed on the metal wiring layer, and

wherein the bottom portion of the contact hole is given the forward tapered shape by forming a forward tapered portion in an upper portion of the anti-reflection layer in the etching.

5. The infrared sensor according to claim 1, wherein an opening of the contact hole, as well as the bottom portion of the contact hole and the side wall portion of the contact hole, has the forward tapered shape.

6. The infrared sensor according to claim 1, wherein an opening of the contact hole is given the forward tapered shape by forming a forward tapered portion in an upper portion of the insulating layer prior to the etching.

7. The infrared sensor according to claim 1, wherein the infrared sensor comprises a thermal infrared sensor.

8. An infrared solid-state image pickup apparatus, comprising the infrared sensor of claim 1.

9. The infrared sensor according to claim 1, wherein the support leg metal wiring layer directly contacts the metal wiring layer.

10. The infrared sensor according to claim 1, wherein the support leg metal wiring layer comprises a thin film that directly contacts the metal wiring layer.

11. The infrared sensor according to claim 1, wherein a support leg insulating layer is formed so as to cover the support leg metal wiring layer, and

wherein the support leg insulating layer extends into the contact hole along an upper surface of the support leg metal wiring layer.

12. The infrared sensor according to claim 11, wherein a thickness of the support leg insulating layer is between 50 nm and 300 nm.

13. The infrared sensor according to claim 12, wherein the support leg insulating layer extends parallel to the bottom portion and the side wall portion that are each shaped into the forward tapered shape.

14. The infrared sensor according to claim 11, wherein the support leg insulating layer extends parallel to the bottom portion and the side wall portion that are each shaped into the forward tapered shape.