METHOD FOR PROVIDING METAL EXTENSION IN BACKSIDE ILLUMINATED SENSOR FOR WAFER LEVEL TESTING

• US 20070117253A1
• Filed: 09/18/2006
• Published: 05/24/2007
• 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
• Granted Patent: US 7,973,380 B2
• Time in Patent Office: Days
• US Class Current: 438/75
• 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. A backside illuminated image sensor comprising:

a substrate;

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

a second bond pad positioned to be accessible from a 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 backside illuminated image sensor of claim 1 wherein the first bond pad is located within a periphery of the backside illuminated image sensor, and the second bond pad is located in a scribe line area adjacent to the backside illuminated sensor.

3. The backside illuminated image sensor 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 backside illuminated image sensor of claim 1 wherein the second bond pad is positioned on the back side of the substrate.

5. The backside illuminated image sensor of claim 4 wherein the second bond pad is substantially vertically aligned with the first bond pad.

6. The backside illuminated image sensor of claim 4 wherein the electrical connection is one or more vias.

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

8. The backside illuminated image sensor of claim 7 wherein width of the opening is from about 30 μ

m to about 200 μ

m.

9. The backside illuminated image sensor of claim 7, further comprises a metal barrier layer overlying the backside of the second bond pad.

10. A method of providing metal extension in a backside illuminated image sensor, the method comprising:

providing a first set of pads in a backside illuminated image sensor on a front side of a substrate;

providing at least one second pad positioned directly below the first set of pads, with reference to the substrate;

electrically coupling the at least one second pad to the first set of pads; and

exposing the at least one second pad to the back side of the substrate.

11. The method of claim 10, further comprises forming an opening through the substrate to expose the at least one second pad for probing.

12. The method of claim 11, wherein width of the opening is from about 30 μ

m to 200 μ

m.

13. The method of claim 12, further comprises forming a metal barrier layer on the at least one second pad.

14. A packaged backside illuminated image sensor comprising:

a backside illuminated sensor having an upper surface and a lower surface, the lower surface comprising a portion of a carrier mechanism, the upper surface 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 via the lower surface; and

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