BACKSIDE ILLUMINATED IMAGE SENSORS WITH STACKED DIES

• US 20140055654A1
• Filed: 08/21/2013
• Published: 02/27/2014
• Est. Priority Date: 08/21/2012
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Inventors: Borthakur, Swarnal, Churchwell, Scott, Boettiger, Ulrich, Sulfridge, Marc, Perkins, Andrew, Lake, Rick
• Granted Patent: US 9,041,840 B2
• Time in Patent Office: Days
• US Class Current: 348/302
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73267 Layer and HDI connectors
• CPC Class Codes: H01L 27/14612 involving a transistor
• CPC Class Codes: H01L 27/14616 characterised by the channel of the transistor, e.g. channel having a doping gradient
• 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: H04N 23/54 Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof

Abstract

An image sensor unit may have a backside-illuminated imager and an image co-processor stacked together. The image co-processor may be mounted in a cavity in a permanent carrier. The permanent carrier may include fluid channels that allow cooling fluid to flow past the image co-process and past the imager, thereby removing excess heat generated by the image sensor unit during operation.

Claims

1. An image sensor unit, comprising:

a backside illuminated imager that contains an array of image pixels, wherein the imager integrated circuit has a front surface on which the array of image pixels is formed and a rear surface through which incident light enters the imager; and

an image co-processor stacked together with the backside illuminated imager.

2. The image sensor unit defined in claim 1 further comprising a permanent carrier, wherein the front surface of the backside illuminated imager is affixed to the permanent carrier.

3. The image sensor unit defined in claim 2 wherein the image co-processor comprises a front side and circuitry on the front side and wherein the front side of the image co-processor is affixed to the permanent carrier.

4. The image sensor unit defined in claim 3 wherein the permanent carrier and the backside illuminated imager each comprise through-silicon vias and redistribution layers, wherein the backside illuminated imager comprises a first plurality of backside bond pads located on the rear surface, and wherein the image co-processor comprises metal contacts that are coupled to the first plurality of backside bond pads through the through-silicon vias and the redistribution layers of both the permanent carrier and the backside illuminated imager.

5. The image sensor unit defined in claim 4 wherein the backside illuminated imager comprises a second plurality of backside bond pads located on the rear surface and wherein the imager comprises frontside bond pads located on the front surface and wherein the frontside bond pads of the imager are coupled to the backside bond pads through the through-silicon vias in the backside illuminated imager.

6. The image sensor unit defined in claim 3 wherein the image co-processor comprises a front side, a backside, and circuitry disposed on the front side and wherein the back side of the image co-processor is affixed to the permanent carrier.

7. The image sensor unit defined in claim 6 further comprising:

at least one photodefinable layer that covers the image co-processor.

8. The image sensor unit defined in claim 7 wherein the permanent carrier, the backside illuminated imager, and the at least one photodefinable layer each comprise through-silicon vias and redistribution layers, wherein the backside illuminated imager comprises a first plurality of backside bond pads located on the rear surface, and wherein the image co-processor comprises metal contacts that are coupled to the first plurality of backside bond pads through the through-silicon vias and the redistribution layers of each of the photodefinable layer, the permanent carrier, and the backside illuminated imager.

9. The image sensor unit defined in claim 1 further comprising:

a permanent carrier affixed to the imager, wherein the permanent carrier has portions that define a cavity and has channels that pass between the cavity and peripheral regions of the permanent carrier, wherein the image co-processor is disposed in the cavity; and

a printed circuit board on which the permanent carrier is mounted, wherein the printed circuit board has at least one fluid inlet and at least one fluid outlet through which cooling fluid passes, wherein the inlet, outlet, and the channels are configured to receive the cooling fluid through the inlet;

pass the cooling fluid through at least a first one of the channels, past the image co-processor such that the cooling fluid absorbs heat from the image co-processor, and through at least a second one of the channels; and

expel the cooling fluid through the outlet.

10. An image sensor unit, comprising:

an imager that contains an array of image pixels;

a permanent carrier affixed to the imager, wherein the permanent carrier has portions that define a cavity and has channels that pass between the cavity and peripheral regions of the permanent carrier;

an image co-processor disposed in the cavity; and

a printed circuit board on which the permanent carrier is mounted, wherein the printed circuit board has at least one fluid inlet and at least one fluid outlet through which cooling fluid passes, wherein the inlet, outlet, and the channels are configured to receive the cooling fluid through the inlet;

pass the cooling fluid through at least a first one of the channels, past the image co-processor such that the cooling fluid absorbs heat from the image co-processor, and through at least a second one of the channels; and

expel the cooling fluid through the outlet.

11. The image sensor unit defined in claim 10 wherein the cooling fluid comprises air.

12. The image sensor unit defined in claim 10 wherein the cooling fluid comprises liquid.

13. The image sensor unit defined in claim 12 further comprising:

an interposed disposed above the imager; and

at least one lens mounted to the interposer.

14. The image sensor unit defined in claim 13 wherein the imager comprises a backside illuminated imager.

15. A system, comprising:

a central processing unit;

memory;

input-output circuitry; and

an imaging device that includes;

an imager that contains an array of image pixels;

a permanent carrier affixed to the imager, wherein the permanent carrier has portions that define a cavity and has channels that pass between the cavity and peripheral regions of the permanent carrier;

an image co-processor disposed in the cavity; and

a printed circuit board on which the permanent carrier is mounted, wherein the printed circuit board has at least one fluid inlet and at least one fluid outlet through which cooling fluid passes, wherein the inlet, outlet, and the channels are configured to receive the cooling fluid through the inlet;

pass the cooling fluid through at least a first one of the channels, past the image co-processor such that the cooling fluid absorbs heat from the image co-processor, and through at least a second one of the channels; and

expel the cooling fluid through the outlet.

16. The system defined in claim 15 wherein the imager comprises a backside illuminated imager.

17. The system defined in claim 16 wherein the cooling fluid comprises cooling liquid.

18. The system defined in claim 17 further comprising epoxy that prevents the cooling liquid from coming into direct contact with the image co-processor.