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

• US 8,623,690 B2
• Filed: 05/19/2009
• Issued: 01/07/2014
• Est. Priority Date: 07/11/2001
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Suzuki, Ryoji, Mabuchi, Keiji, Mori, Tomonori
• Primary Examiner(s): SMITH, BRADLEY
• Application Number:
  US12/468,692
• Publication Number:
  US 20090227064A1
• Time in Patent Office: 1,694 Days
• Field of Search: 438/57, 438/69, 438/70, 257290-294
• US Class Current: 438/70
• 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. A method of producing a pixel, comprising:

forming a device layer in a substrate, the device layer comprising a photo-electric conversion device and active device; and

forming a wiring layer over a first side of the device layer, the wiring layer comprising wirings for the active device and the first side of the device layer being opposite to a light receiving side

wherein the step of forming the device layer includes forming a photo-electric conversion region configured to receive incident light at the light receiving side of the device layer, and

wherein the step of forming the device layer further includes forming a floating diffusion portion.

2. A method of producing a pixel according to claim 1,

wherein the step of forming the device layer further includes forming the photo-electric conversion region such that the photo-electric conversion region extends in a width direction to overlap, in a depth direction, at least a portion of the transfer transistor and at least a portion of a floating diffusion portion, the width direction being parallel to the first side of the substrate and the depth direction being perpendicular to the first side of the substrate.

3. A method of producing a pixel according to claim 1,

wherein the step of forming the device layer further includes forming the photo-electric conversion region such that the photo-electric conversion region extends in a width direction to completely overlap, in a depth direction, the floating diffusion portion, the width direction being parallel to the first side of the substrate and the depth direction being perpendicular to the first side of the substrate.

4. A method of producing a pixel, the method comprising the steps of:

forming a device layer on a first side of a substrate, the device layer comprising a photo-electric conversion device and an active device;

forming a wiring layer over a first side of the device layer, the wiring layer comprising wirings for the active device and the first side of the device layer facing away from the substrate; and

forming a substrate support layer on a first side of the wiring layer, the first side of the wire layer facing away from the device layer,

wherein the step of forming the device layer includes forming a photo-electric conversion region configured to receive incident light at a second side of the device layer, the second side of the device layer facing toward the substrate, and

wherein the step of forming the device layer further includes forming the photo-electric conversion region to have a greater surface area on the second side of the device layer than the first side of the device layer.

5. A method of producing a pixel, comprising:

forming a device layer in a substrate, the device layer comprising a photo-electric conversion device and active device; and

forming a wiring layer over a first side of the device layer, the wiring layer comprising wirings for the active device and the first side of the device layer being opposite to a light receiving side,

wherein the step of forming the device layer includes forming a photo-electric conversion region configured to receive incident light at the light receiving side of the device layer, and

wherein the step of forming the device layer further includes forming a shallow impurity region in the photo-electric conversion region at a surface of the second side of the device layer.

6. A method of producing a pixel according to claim 5,

wherein the shallow impurity region is a p-type region.

7. A method of producing a pixel according to claim 6,

wherein the step of forming the device layer further includes forming a well at a side of said photo-electric conversion region, the well being connected to the shallow impurity region.

8. A method of producing a pixel, comprising:

forming a device layer in a substrate, the device layer comprising a photo-electric conversion device and active device; and

forming a wiring layer over a first side of the device layer, the wiring layer comprising wirings for the active device and the first side of the device layer being opposite to a light receiving side

wherein the step of forming the device layer includes forming a photo-electric conversion region configured to receive incident light at the light receiving side of the device layer, and

wherein the step of forming the device layer further includes forming a p-type region at a surface portion of the photo-electric conversion region at the first side of the device layer.

9. A method of producing a pixel, comprising:

forming a device layer in a substrate, the device layer comprising a photo-electric conversion device and active device; and

forming a wiring layer over a first side of the device layer, the wiring layer comprising wirings for the active device and the first side of the device layer being opposite to a light receiving side,

polishing a second side of the substrate until the substrate becomes a predetermined thickness, the second side of the substrate facing opposite from the first side of the substrate,

wherein the step of forming the device layer includes forming a photo-electric conversion region configured to receive incident light at the light receiving side of the device layer, and

wherein the step of polishing the second side includes polishing the second side of the substrate until the thickness of the substrate is in the range of 5 to 15 μ

m.

10. A method of producing a pixel, the method comprising the steps of:

forming a device layer on a first side of a substrate, the device layer comprising a photo-electric conversion device and an active device;

forming a wiring layer over a first side of the device layer, the wiring layer comprising wirings for the active device and the first side of the device layer facing away from the substrate; and

forming an SiO₂ layer on the second side of the substrate,

wherein the step of forming the device layer includes forming a photo-electric conversion region configured to receive incident light at a second side of the device layer, the second side of the device layer facing toward the substrate, and

wherein the step of forming the device layer further includes forming the photo-electric conversion region to have a greater surface area on the second side of the device layer than the first side of the device layer.

11. A method of producing a pixel according to claim 10, further comprising a step of

forming a light shielding layer on the SiO₂ layer, the light shield film having opening portions that allow passage of the incident light to the photo-electric conversion region.

12. A method of producing a pixel according to claim 11, further comprising a step of

forming a passivation layer on the light shielding layer and, at the opening portions, on the SiO₂ layer.