Active pixel sensor having a sensor wafer connected to a support circuit wafer

• US 8,049,256 B2
• Filed: 10/04/2007
• Issued: 11/01/2011
• Est. Priority Date: 10/05/2006
• Status: Active Grant

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Inventors: Guidash, Robert M.
• Primary Examiner(s): Sefer; A.
• Assistant Examiner(s): Nguyen; Dilinh P
• Application Number:
  US11/867,199
• Publication Number:
  US 20080083939A1
• Time in Patent Office: 1,489 Days
• Field of Search: 257/290, 257/291, 257/292, 257/239, 257/432, 257/232, 257/E27.133, 257/E31.128
• US Class Current: 257/292
• 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 27/14627 Microlenses
• CPC Class Codes: H01L 27/14634 Assemblies, i.e. Hybrid structures
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/1464 Back illuminated imager structures
• CPC Class Codes: H01L 27/14641 Electronic components shared by two or more pixel-elements, e.g. one amplifier shared by two pixel elements
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 27/14687 Wafer level processing

Abstract

A vertically-integrated active pixel sensor includes a sensor wafer connected to a support circuit wafer. Inter-wafer connectors or connector wires transfer signals between the sensor wafer and the support circuit wafer. The active pixel sensor can be fabricated by attaching the sensor wafer to a handle wafer using a removable interface layer. Once the sensor wafer is attached to the handle wafer, the sensor wafer is backside thinned to a given thickness. The support circuit wafer is then attached to the sensor wafer and the handle wafer separated from the sensor wafer.

Claims

1. An active pixel sensor comprising:

(a) a sensor wafer including;

an array of active pixel regions, each active pixel region including;

a photodetector for collecting charge in response to light;

readout circuitry for reading charge from the photodetector; and

two or more interconnects connected to the readout circuitry, wherein each interconnect in the two or more interconnects is connected to corresponding readout circuitry in at least one other active pixel region in the array;

(b) a support circuit wafer connected to the sensor wafer, wherein the support circuit wafer includes;

support circuitry for the array of active pixel regions; and

a plurality of interconnects connected to the support circuitry; and

(c) a plurality of inter-wafer connector wires for transferring control and timing signals from the support circuit wafer to the sensor wafer and column output signals from the sensor wafer to the support circuit wafer, wherein each inter-wafer connector wire is connected between at least one interconnect on the sensor wafer and a corresponding interconnect on the support circuit wafer at a perimeter edge of the array of active pixel regions.

2. The active pixel sensor of claim 1, wherein the sensor wafer comprises a back-side illuminated sensor wafer.

3. The active pixel sensor of claim 1, wherein the sensor wafer comprises a front-side illuminated sensor wafer.

4. The active pixel sensor of claim 1, wherein the active pixel sensor is disposed in an image capture device.

5. The active pixel sensor of claim 1, wherein the readout circuitry comprises:

a charge-to-voltage conversion mechanism; and

a transfer gate disposed between the photodetector and the charge-to-voltage conversion mechanism for transferring the charge from the photodetector to the charge-to-voltage conversion mechanism, wherein one of the two or more interconnects is connected to the transfer gate.

6. The active pixel sensor of claim 1, wherein the readout circuitry comprises:

a charge-to-voltage conversion mechanism;

a transfer gate disposed between the photodetector and the charge-to-voltage conversion mechanism for transferring the charge from the photodetector to the charge-to-voltage conversion mechanism; and

a transistor connected to the charge-to-voltage conversion mechanism, wherein one of the two or more interconnects is connected to the transistor.

7. An active pixel sensor comprising:

(a) a sensor die including;

an array of active pixel regions, each active pixel region including;

a photodetector for collecting charge in response to light;

readout circuitry for reading charge from the photodetector; and

two or more interconnects connected to the readout circuitry, wherein each interconnect in the two or more interconnects is connected to corresponding readout circuitry in at least one other active pixel region in the array;

(b) a support circuit die connected to the sensor die, wherein the support circuit die includes;

support circuitry for the array of active pixel regions; and

a plurality of interconnects connected to the support circuitry; and

(c) a plurality of inter-wafer connector wires for transferring control and timing signals from the support circuit die to the sensor die and column output signals from the sensor die to the support circuit die, wherein each inter-wafer connector wire is connected between at least one interconnect on the sensor die and a corresponding interconnect on the support circuit die at a perimeter edge of the array of active pixel regions.

8. The active pixel sensor of claim 7, wherein the sensor die comprises a back-side illuminated sensor die.

9. The active pixel sensor of claim 7, wherein the sensor die comprises a front-side illuminated sensor die.

10. The active pixel sensor of claim 7, wherein the readout circuitry comprises:

a charge-to-voltage conversion mechanism; and

a transfer gate disposed between the photodetector and the charge-to-voltage conversion mechanism for transferring the charge from the photodetector to the charge-to-voltage conversion mechanism, wherein one of the two or more interconnects is connected to the transfer gate.

11. The active pixel sensor of claim 7, wherein the readout circuitry comprises:

a charge-to-voltage conversion mechanism;

a transfer gate disposed between the photodetector and the charge-to-voltage conversion mechanism for transferring the charge from the photodetector to the charge-to-voltage conversion mechanism; and

a transistor connected to the charge-to-voltage conversion mechanism, wherein one of the two or more interconnects is connected to the transistor.