Pad design for backside illuminated image sensor

• US 9,142,586 B2
• Filed: 02/18/2010
• Issued: 09/22/2015
• Est. Priority Date: 02/24/2009
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Wang, Wen-De, Yaung, Dun-Nian, Liu, Jen-Cheng, Chuang, Chun-Chieh, Lin, Jeng-Shyan
• Primary Examiner(s): Sun, Yu-Hsi D
• Assistant Examiner(s): SINGAL, ANKUSH K
• Application Number:
  US12/708,167
• Publication Number:
  US 20100213560A1
• Time in Patent Office: 2,042 Days
• Field of Search: 438/73, 438/118, 257/E21.506, 257/43, 257/E31.122, 257/700, 257/773, 257/432, 257/E31.127, 257/E27.133, 257/477
• US Class Current: 1/1
• CPC Class Codes: H01L 23/481 Internal lead connections, e.g. via connections, feedthrough structures
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/1464 Back illuminated imager structures
• CPC Class Codes: H01L 27/14683 Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof not peculiar thereto H01L21/00

Abstract

A semiconductor image sensor device includes first and second semiconductor substrates. A pixel array and a control circuit are formed in a first surface of the first substrate. An interconnect layer is formed over the first surface of the first substrate and electrically connects the control circuit to the pixel array. A top conducting layer is formed over the interconnect layer to have electrical connectivity with at least one of the control circuit or the pixel array via the interconnect layer. A surface of a second substrate is bonded to the top conducting layer. A conductive through-silicon-via (TSV) passes through the second substrate, and has electrical connectivity with the top conducting layer. A terminal is formed on an opposite surface of the second substrate, and electrically connected to the TSV.

Claims

1. An image sensor device, comprising:

a device substrate having a pixel region and a circuit region, wherein the pixel region comprises a photo-detection region;

a pixel array formed on the device substrate and within the pixel region;

a control circuit formed on the device substrate and within the circuit region;

an interconnect structure formed over the pixel array and the control circuit, the interconnect structure electrically connecting the control circuit to the pixel array;

a conducting layer formed on the interconnect structure;

a carrier substrate overlying the conducting layer; and

a conductive via passing through the carrier substrate entirely within the photo-detection region, electrically connected to the conducting layer and at least partially embedded in the conducting layer,

wherein the conducting layer comprises a portion formed in the pixel region, the portion serving as a pad.

2. The image sensor device of claim 1, wherein the pad is solid.

3. The image sensor device of claim 1, further comprising an insulation layer surrounding a sidewall of the conductive via.

4. The image sensor device of claim 1, wherein the image sensor device is a backside illuminated image sensor device.

5. The image sensor device of claim 4, wherein the device substrate has a front side and a backside, and the pixel array is formed on the front side of the device substrate.

6. The image sensor device of claim 5, further comprising a filter element on the backside of the device substrate.

7. The image sensor device of claim 1, wherein the conductive via has a constant width.

8. The image sensor device of claim 1, further comprising a re-routing layer electrically connected to the conductive via at a location in the pixel region.

9. The image sensor device of claim 8, wherein the re-routing layer includes a portion within the circuit region.

10. An image sensor device, comprising:

a device substrate having a pixel region and a circuit region, wherein the pixel region comprises a photo-detection region;

a pixel array formed on the device substrate within the pixel region;

a control circuit formed on the device substrate within the circuit region;

an interconnect structure formed over the pixel array and the control circuit, electrically connecting the control circuit to the pixel array;

a conducting layer formed on the interconnect structure;

a carrier substrate overlying the conducting layer;

a conductive via, located in the photo-detection region, passing through the carrier substrate, electrically connected to the conducting layer and at least partially embedded in the conducting layer; and

a re-routing layer electrically connected to the conductive via at a location within the pixel region,

wherein the conducting layer comprises a solid portion formed in the pixel region, serving as a pad.

11. The image sensor device of claim 10, further comprising an insulation layer surrounding a sidewall of the conductive via.

12. The image sensor device of claim 10, wherein the device substrate has a front side and a backside, the image sensor device is illuminated from the backside and the pixel array is formed on the front side of the device substrate.

13. The image sensor device of claim 10, wherein the conductive via has a constant width.

14. The image sensor device of claim 10, wherein the conductive via has a tapered width.

20. The image sensor device of claim 10, wherein the re-routing layer includes a portion within the circuit region.

15. A method of fabricating a semiconductor image sensor device, said method comprising:

forming a pixel array on a device substrate the pixel array defining a pixel region of the device substrate, wherein the pixel region comprises a photo-detection region;

forming a control circuit on the device substrate the control circuit defining a circuit region of the device substrate;

forming an interconnect structure over the pixel array and the control circuit, electrically connecting the control circuit to the pixel array;

bonding a carrier substrate to a conducting layer;

forming a conductive via passing through the carrier substrate entirely within the photo-detection region that is electrically connected to the conducting layer and at least partially embedded in the conducting layer; and

forming the conducting layer on the interconnect structure;

wherein the conducting layer comprises a portion formed in the pixel region, serving as a pad.

16. The method of claim 15, wherein the pad is formed of a solid conductor.

17. The method of claim 15, wherein the conductive via is formed over the pad.

18. The method of claim 15, wherein an insulation layer is formed on a sidewall of the conductive via.

19. The method of claim 15, wherein the device substrate has a front side and a backside, the image sensor device is illuminated from the backside and the pixel array is formed on the front side of the device substrate.