X-Y address type solid state image pickup device and method of producing the same

• US 20080067556A1
• Filed: 10/30/2007
• Published: 03/20/2008
• Est. Priority Date: 07/11/2001
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Mori, Tomonori, Suzuki, Ryoji, Mabuchi, Keiji
• Granted Patent: US 8,604,575 B2
• Time in Patent Office: Days
• US Class Current: 257/225
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14623 Optical shielding
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/1464 Back illuminated imager structures
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements
• CPC Class Codes: H01L 27/14687 Wafer level processing
• CPC Class Codes: H01L 27/14689 MOS based technologies
• CPC Class Codes: H01L 31/02164 for shielding light, e.g. light blocking layers, cold shields for infrared detectors
• CPC Class Codes: H01L 31/0232 Optical elements or arrangements associated with the device H01L31/0236 takes precedence; for photovoltaic cells H01L31/054; for photovoltaic modules H02S40/20
• CPC Class Codes: H01L 31/02327 the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216
• CPC Class Codes: H04N 25/79 Arrangements of circuitry being divided between different or multiple substrates, chips or circuit boards, e.g. stacked image sensors

Abstract

In an X-Y address type solid state image pickup device represented by a CMOS image sensor, a back side light reception type pixel structure is adopted in which a wiring layer is provided on one side of a silicon layer including photo-diodes formed therein, and visible light is taken in from the other side of the silicon layer, namely, from the side (back side) opposite to the wiring layer. Wiring can be made without taking a light-receiving surface into account, and the degree of freedom in wiring for the pixels is enhanced.

Claims

1-6. -6. (canceled)

7. A solid state image pickup device comprising

a plurality of unit pixels each comprising an active device for converting a signal charge obtained through photo-electric conversion by a photo-electric conversion device into an electrical signal and outputting said electrical signal,

wherein a wiring layer comprising wirings for said active devices is provided on one side of a device layer comprising said photo-electric conversion device, and incident light is taken into said photo-electric conversion device from the other side of said device layer and

wherein an impurity region is formed in a light-receiving-side of said device layer.

8. A solid state image pickup device as set forth in claim 7,

wherein said photo-electric conversion device is in a pixel area and

said impurity region is not in a peripheral circuit area which is around said pixel area.

9. A solid state image pickup device as set forth in claim 7,

wherein said impurity region is formed into said one side of said device layer from the other side of said device layer between said photo-electric conversion devices.

10. A solid state image pickup device as set forth in claim 7,

wherein an area of said impurity region on said other side of said device layer is greater than an area of said impurity region on said one side of said device layer.

11. A solid state image pickup device as set forth in claim 9,

wherein said photo-electric conversion device is in a pixel area and

a second impurity region is formed in said one side in a peripheral circuit area which is around said pixel area and

said second impurity region extends to said other side of said device layer.

12. A solid state image pickup device as set forth in claim 7,

wherein the thickness of said device layer is in the range of 5 to 15 μ

m.

13. A solid state image pickup device as set forth in claim 7,

wherein said photo-electric conversion device extends to said one side of said device layer.

14. A solid state image pickup device as set forth in claim 7,

wherein said photo-electric conversion device is formed to be greater in surface area on said other side than on said one side.

15. A solid state image pickup device comprising:

a plurality of unit pixels each comprising an active device for converting a signal charge obtained through photo-electric conversion by a photo-electric conversion device into an electrical signal and outputting said electrical signal,

wherein a wiring layer comprising wirings for said active devices is provided on one side of a device layer comprising said photo-electric conversion device, and incident light is taken into said photo-electric conversion device from the other side of said device layer and

further comprising a light shielding layer with a portion of an opening formed in said other side of said device layer.

16. A solid state image pickup device comprising:

a plurality of unit pixels each comprising an active device for converting a signal charge obtained through photo-electric conversion by a photo-electric conversion device into an electrical signal and outputting said electrical signal,

wherein a wiring layer comprising wirings for said active devices is provided on one side of a device layer comprising said photo-electric conversion device, and incident light is taken into said photo-electric conversion device from the other side of said device layer and

further comprising a support substrate disposed at said other side of said device layer.

17. A solid state image pickup device as set forth in claim 16,

wherein said support substrate has at least one via hole and

a conductive material buried in said via hole connects between a pad and outer-terminal and

said pad is formed at said other side of said device layer.

18. A method of producing a solid state image pickup device comprising

a plurality of unit pixels each comprising an active device for converting a signal charge obtained though photo-electric conversion by a photo-electric conversion device into an electrical signal and outputting said electrical signal,

said unit pixels being arranged on a matrix form, said method comprising sequentially:

a first step of forming said photo-electric conversion devices and said active devices;

a second step of forming a wiring layer comprising wirings for said active devices, on one side of a device layer comprising said photo-electric conversion devices and said active devices; and

a third step of polishing the other side of said device layer so that the thickness of said substrate becomes a predetermined thickness.

19. A method of producing a solid state image pickup device as set forth in claim 18,

wherein the step of forming said wiring layer is done by using an alignment mark formed at said other side of said device layer in said second step.

20. A method of producing a solid state image pickup device as set forth in claim 19,

wherein said alignment mark is a trench structure.

21. A method of producing a solid state image pickup device as set forth in claim 18,

wherein polishing is conducted in said third step so that the thickness of said substrate becomes in the range of 5 to 15 μ

m.

22. An X-Y address type solid-state image pickup device comprising a plurality of unit pixels comprising an active device for converting a signal charge obtained through photo-electric conversion by a photo-electric conversion device into an electrical signal and outputting said electrical signal,

wherein a wiring layer comprising wirings for said active device is provided at a first surface side of the device layer comprising said photo-electric conversion device, and incident light is taken into said photo-electric conversion device from a second surface side, and wherein the photo-electric conversion device is comprised of a first impurity region and a second impurity region oozing. Concentration is more than that of the first impurity region and the second impurity region is located closer to the first surface side than the first impurity region;

and further wherein a surface area of the second surface side of the first impurity region is greater in surface area then a corresponding surface area of the second impurity region.