Method for providing metal extension in backside illuminated sensor for wafer level testing

• US 7,973,380 B2
• Filed: 09/18/2006
• Issued: 07/05/2011
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Hsu, Tzu-Hsuan, Yaung, Dun-Nian
• Primary Examiner(s): Wagner; Jenny L.
• Application Number:
  US11/532,674
• Publication Number:
  US 20070117253A1
• Time in Patent Office: 1,751 Days
• Field of Search: 257/448, 257/433, 257/459, 257/460, 257/E27.131, 250/214.1, 250/214.R
• US Class Current: 257/460
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/1464 Back illuminated imager structures
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 31/0203 Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80

Abstract

A method of providing metal extension in a backside illuminated image sensor is provided in the present disclosure. In one embodiment, a first set of pads and a second set of pads, and a metal layer are provided in a backside illuminated image sensor. The first set of pads are electrically coupled to the second set of pads through the metal layer, and a pad in the second set of pads is exposed to the surface of the backside illuminated image sensor for testing. In an alternative embodiment, a first set of pads, at least one second pad directly positioned over the first set of pads are provided in a backside illuminated image sensor. The first set of pads are electrically coupled to the at least one second pad and the at least one second pad is exposed to the surface of the backside illuminated image sensor for testing.

Claims

1. An apparatus comprising a back side illuminated image sensor that includes:

a substrate having a front side and a back side that is opposite to the front side;

an image-sensing pixel formed within the substrate, the pixel being operable to sense radiation that enters the substrate from the back side;

a first bond pad positioned above the front side of the substrate;

a second bond pad positioned to be accessible from the back side of the substrate; and

an electrical connection for connecting the first and second bond pads to form a metal extension bond pad.

2. The apparatus of claim 1 wherein the first bond pad is located within a periphery of the back side illuminated image sensor, and the second bond pad is located in a scribe line area adjacent to the back side illuminated sensor.

3. The apparatus of claim 2 wherein the first bond pad is part of a first bond pad set comprising pads in a plurality of metal layers, and wherein the electrical connection is provided by a metal line in at least one of the plurality of metal layers extending to the second bond pad.

4. The apparatus of claim 1 wherein the second bond pad is positioned on the back side of the substrate.

5. The apparatus of claim 4 wherein the second bond pad is substantially vertically aligned with the first bond pad.

6. The apparatus of claim 4 wherein the electrical connection is one or more vias.

7. The apparatus of claim 4, further comprises an opening formed through the substrate for probing from a back side of the second bond pad.

8. The apparatus of claim 7 wherein width of the opening is from about 30 um to about 200 um.

9. The apparatus of claim 7, further comprises a metal barrier layer overlying the back side of the second bond pad.

10. The image sensor of claim 1, wherein the first and second bond pads are both positioned above the front side of the substrate.

11. The apparatus of claim 1, wherein the image sensor further includes:

an interconnect structure that is located over the front side of the substrate; and

a lens that is located over the back side of the substrate.

12. An apparatus comprising:

a backside illuminated sensor having a frontside and a backside, the frontside including a pixel, the backside including a first portion for receiving an image to be sensed by the pixel and a second portion having a plurality of exposed extended bond pads;

a package including a cavity and a plurality of external connectors, the cavity having a holder portion for engaging and securing the backside illuminated image sensor; and

a plurality of electrical conductors connected between the plurality of exposed extended bond pads and the plurality of external connectors.

13. An image sensor comprising:

a substrate having a first surface, a second surface opposed to the first surface, and an opening between the first and second surfaces;

a first bond pad positioned over the first surface of the substrate;

a second bond pad positioned to be vertically aligned with the opening in the substrate;

an electrical connection for connecting the first and second bond pads; and

a pixel formed in the substrate, the pixel being adjacent to the first surface and being operable to detect radiation projected toward the pixel through the second surface.

14. The image sensor of claim 13, further including a plurality of light-sensing pixels formed on the first surface.

15. The image sensor of claim 14, further including colorfilters and microlenses formed on the second surface.

16. The image sensor of claim 13 wherein the first bond pad is located within a periphery of the image sensor, and the second bond pad is located in a scribe line area adjacent to the image sensor.

17. The image sensor of claim 16 wherein the first bond pad is part of a first bond pad set comprising pads in a plurality of metal layers, and wherein the electrical connection is provided by a metal line in at least one of the plurality of metal layers extending to the second bond pad.

18. The image sensor of claim 13 wherein the second bond pad is positioned on the second surface.

19. The image sensor of claim 18, wherein the second bond pad is substantially vertically aligned with the first bond pad.

20. The image sensor of claim 13, wherein the first and second bond pads are both located over the first surface.