Image sensor and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-9978791-B2
Application number	US-201514815366-A
Country	US
Kind code	B2
Filing date	Jul 31, 2015
Priority date	Jul 31, 2015
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

An image sensor structure and a method for forming the same are provided. The image sensor structure includes a first substrate including a first radiation sensing region and a first interconnect structure formed over a front side of the first substrate. The image sensor structure further includes a second substrate including a second radiation sensing region and a second interconnect structure formed over a front side of the second substrate. In addition, the first interconnect structure is bonded with the second interconnect structure.

First claim

What is claimed is:

1. An image sensor structure, comprising:
a first substrate comprising a plurality of first radiation sensing regions;
a first interconnect structure formed over a front side of the first substrate;
a second substrate comprising a plurality of second radiation sensing regions; and
a second interconnect structure formed over a front side of the second substrate,
wherein the first interconnect structure is bonded with the second interconnect structure, the first interconnect structure comprises a first conductive feature, the second interconnect structure comprises second conductive features, and the first conductive feature and the second conductive features are located directly above a space between two of the plurality of first radiation sensing regions and below a space between two of the plurality of second radiation sensing regions, and the first conductive feature overlaps with the two of the plurality of second radiation sensing regions without overlapping with the two of the plurality of first radiation sensing regions.

2. The image sensor structure as claimed in claim 1 , further comprising:
a color filter layer formed over a back side of the second substrate.

3. The image sensor structure as claimed in claim 1 , wherein the second conductive features are designed to enable radiation entering from the second substrate to pass through the second interconnect structure.

4. The image sensor structure as claimed in claim 1 , wherein the first radiation sensing region has a first width, and the second radiation sensing region has a second width which is smaller than the first width.

5. The image sensor structure as claimed in claim 1 , wherein the first substrate has a first thickness, and the second substrate has a second thickness which is smaller than the first thickness.

6. The image sensor structure as claimed in claim 1 , wherein the first radiation sensing region is configured to sense near infrared radiation, and the second radiation sensing region is configured to sense visible radiation.

7. An image sensor structure, comprising:
a first substrate comprising a first radiation sensing region at a front side of the first substrate;
a first interconnect structure comprising a first conductive feature formed over the front side of the first substrate and a first conductive pad;
a second substrate comprising a second radiation sensing region and a third radiation sensing region at a front side of the second substrate, wherein the second radiation sensing region in the second substrate partially overlaps with the first radiation sensing region in the first substrate;
a second interconnect structure comprising second conductive features formed over the front side of the second substrate and a second conductive pad; and
a color filter layer formed over a back side of the second substrate,
wherein the first interconnect structure is bonded to the second interconnect structure, and the first conductive feature, the first conductive pad and the second conductive pad are located directly under a space between the second radiation sensing region and the third radiation sensing region and overlaps with both the second radiation sensing region and the third radiation sensing region.

8. The image sensor structure as claimed in claim 7 , wherein the second conductive features are arranged to enable radiation incident from the back side of the second substrate to pass through the second conductive features.

9. The image sensor structure as claimed in claim 7 , wherein the first radiation sensing region is configured to sense near infrared radiation, and the second radiation sensing region is configured to sense visible radiation.

10. The image sensor structure as claimed in claim 7 , wherein the first radiation sensing region is configure to sense radiation entering from the back side of the second substrate.

11. A method for manufacturing an image sensor structure, comprising:
forming a first radiation sensing region in a front side of a first substrate;
forming a first interconnect structure comprising first conductive features over the front side of the first substrate;
forming a plurality of second radiation sensing regions in a front side of a second substrate;
forming a second interconnect structure comprising second conductive features over the front side of the second substrate; and
bonding the first interconnect structure to the second interconnect structure by directly bonding a first conductive pad in the first interconnect structure with a second conductive pad in the second interconnect structure so that the first radiation sensing region overlaps with at least one of the plurality of second radiation sensing regions,
wherein the first conductive feature, the second conductive features, the first conductive pad and the second conductive pad are located directly under a space between two of the plurality of the second radiation sensing regions and overlap with the two of the plurality of the second radiation sensing regions.

12. The method for manufacturing an image sensor structure as claimed in claim 11 , further comprising:
polishing a back side of the second substrate to expose the second radiation sensing region from the back side of the second substrate after the first interconnect structure and the second interconnect structure are bonded.

13. The method for manufacturing an image sensor structure as claimed in claim 11 , further comprising:
forming a color filter layer over a back side of the second substrate.

14. The method for manufacturing an image sensor structure as claimed in claim 13 , wherein the first radiation sensing region in the first substrate overlaps the second radiation sensing region in the second substrate.

15. The method for manufacturing an image sensor structure as claimed in claim 11 , wherein the first conductive pad and the second conductive pad are reflowed to bond with each other.

16. The method for manufacturing an image sensor structure as claimed in claim 11 , wherein the first radiation sensing region is configured to sense near infrared radiation, and the second radiation sensing region is configured to sense visible radiation.

17. The image sensor structure as claimed in claim 7 , wherein the first conductive features are arranged to enable radiation incident from the back side of the second substrate to pass through the first conductive features.

18. The image sensor structure as claimed in claim 8 , wherein the first conductive features are arranged to enable radiation incident from the back side of the second substrate to sequentially pass through the color filter layer, the second radiation sensing region, the second conductive features, and the first conductive features to reach the first radiation sensing region.

19. The method for manufacturing an image sensor structure as claimed in claim 11 , further comprising:
aligning the first conductive structure with the second conductive structure before bonding the first interconnect structure to the second interconnect structure.

20. The image sensor structure as claimed in claim 7 , wherein the first conductive pad is in direct contact with the second conductive pad.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Lu Tse-Hua
• Wang Ching-Chun
• Sze Jhy-Jyi
• Hung Ping-Fang

Classifications

• H01L27/1464

  Electricity · mapped topic

• H01L27/14621 Primary

  Electricity · mapped topic

• H01L27/14636

  Electricity · mapped topic

• H01L27/14634

  Electricity · mapped topic

• H01L27/1469

  Electricity · mapped topic