Infrared imager with integrated metal layers

• US 9,848,134 B2
• Filed: 11/27/2013
• Issued: 12/19/2017
• Est. Priority Date: 04/23/2010
• Status: Active Grant

• Current Assignee: Teledyne FLIR LLC (Teledyne Technologies Incorporated)
• Original Assignee: FLIR Systems, Inc. (Teledyne Technologies Incorporated)
• Inventors: Simolon, Brian, Kurth, Eric A., Barskey, Steve, Nussmeier, Mark, Hgasten, Nicholas, Hoelter, Theodore R., Strandemar, Katrin, Boulanger, Pierre, Sharp, Barbara
• Primary Examiner(s): Anyikire, Chikaodili E
• Application Number:
  US14/092,794
• Publication Number:
  US 20140092256A1
• Time in Patent Office: 1,483 Days
• CPC Class Codes: H01L 27/1469 Assemblies, i.e. hybrid integration
• CPC Class Codes: H04N 25/62 Detection or reduction of noise due to excess charges produced by the exposure, e.g. smear, blooming, ghost image, crosstalk or leakage between pixels
• CPC Class Codes: H04N 25/67 applied to fixed-pattern noise, e.g. non-uniformity of response
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

Various techniques are provided for implementing, operating, and manufacturing infrared imaging devices using integrated circuits. In one example, a system includes a focal plane array (FPA) integrated circuit comprising an array of infrared sensors adapted to image a scene, a plurality of active circuit components, a first metal layer disposed above and connected to the circuit components, a second metal layer disposed above the first metal layer and connected to the first metal layer, and a third metal layer disposed above the second metal layer and below the infrared sensors. The third metal layer is connected to the second metal layer and the infrared sensors. The first, second, and third metal layers are the only metal layers of the FPA between the infrared sensors and the circuit components. The first, second, and third metal layers are adapted to route signals between the circuit components and the infrared sensors.

Claims

1. A system comprising:

a focal plane array (FPA) integrated circuit comprising;

an array of infrared sensors adapted to image a scene;

a plurality of active circuit components;

a first metal layer disposed above and connected to the circuit components;

a second metal layer disposed above the first metal layer and connected to the first metal layer;

a third metal layer disposed above the second metal layer and below the infrared sensors, wherein the third metal layer is connected to the second metal layer and the infrared sensors;

wherein the first, second, and third metal layers are the only metal layers of the FPA between the infrared sensors and the circuit components; and

wherein the first, second, and third metal layers are adapted to route signals between the circuit components and the infrared sensors.

2. The system of claim 1, wherein:

the circuit components comprise a read out integrated circuit (ROIC) comprising a plurality of column amplifiers, a column multiplexer, and a row multiplexer;

the signals correspond to image frames captured by the infrared sensors; and

the first, second, and third metal layers are adapted to route the signals from the infrared sensors to the ROIC.

3. The system of claim 1, wherein the circuit components comprise:

a bias circuit adapted to provide a bias voltage in response to a regulated voltage selected from a range of approximately 1.5 volts to approximately 2.8 volts; and

a low-dropout regulator (LDO) adapted to provide the regulated voltage to the bias circuit in response to an external supply voltage selected from a range of approximately 2.8 volts to approximately 11 volts, wherein the signals comprise the bias voltage routed from the bias circuit to the infrared sensors through the first, second, and third metal layers.

4. The system of claim 1, wherein:

the circuit components comprise MOSFET transistors;

the signals are first signals;

the second metal layer is adapted to route second signals between first and second ones of the circuit components; and

the third metal layer is adapted to route third signals between third and fourth ones of the circuit components.

5. The system of claim 1, wherein the FPA integrated circuit further comprises:

a plurality of insulating layers above the active circuit components and below the infrared sensors, wherein the circuit components, the first metal layer, the second metal layer, the third metal layer, and the infrared sensors are separated by corresponding ones of the insulating layers;

a first set of vias passing through a first one of the insulating layers to connect the first metal layer to the circuit components;

a second set of vias passing through a second one of the insulating layers to connect the second metal layer to the first metal layer;

a third set of vias passing through a third one of the insulating layers to connect the third metal layer to the second metal layer; and

a fourth set of vias passing through a fourth one of the insulating layers to connect the infrared sensors to the third metal layer.

6. The system of claim 1, wherein:

the infrared sensors are microbolometers;

a size of the array of infrared sensors is approximately 80 by 60; and

the system is an infrared imaging module adapted to be inserted into a socket having a size less than approximately 8.5 mm by 8.5 mm.

7. The system of claim 1, further comprising a processor adapted to process an intentionally blurred image frame, wherein the blurred image frame comprises blurred thermal image data associated with the scene and noise introduced by the system, wherein the processor is adapted to:

use the blurred image frame to determine a plurality of non-uniformity correction (NUC) terms to reduce at least a portion of the noise; and

apply the NUC terms to image frames captured by the infrared sensors.

8. A method comprising:

imaging a scene using a focal plane array (FPA) integrated circuit comprising;

an array of infrared sensors adapted to image the scene,

a plurality of active circuit components,

a first metal layer disposed above and connected to the circuit components,

a second metal layer disposed above the first metal layer and connected to the first metal layer,

a third metal layer disposed above the second metal layer and below the infrared sensors, wherein the third metal layer is connected to the second metal layer and the infrared sensors, and

wherein the first, second, and third metal layers are the only metal layers of the FPA between the infrared sensors and the circuit components; and

routing signals between the circuit components and the infrared sensors through the first, second, and third metal layers.

9. The method of claim 8, wherein:

the circuit components comprise a read out integrated circuit (ROIC) comprising a plurality of column amplifiers, a column multiplexer, and a row multiplexer;

the method further comprises capturing image frames using the infrared sensors;

the signals correspond to the image frames; and

the routing comprises routing the signals from the infrared sensors to the ROIC through the first, second, and third metal layers.

10. The method of claim 8, wherein:

the circuit components comprise a bias circuit and a low-dropout regulator (LDO);

the signals comprise a bias voltage;

the routing comprises routing the bias voltage from the bias circuit to the infrared sensors through the first, second, and third metal layers; and

the method further comprises;

generating the bias voltage using the bias circuit in response to a regulated voltage selected from a range of approximately 1.5 volts to approximately 2.8 volts, and

providing the regulated voltage from the LDO to the bias circuit in response to an external supply voltage selected from a range of approximately 2.8 volts to approximately 11 volts.

11. The method of claim 8, wherein:

the circuit components comprise MOSFET transistors;

the signals are first signals; and

the method further comprises;

routing second signals between first and second ones of the circuit components using the second metal layer, and

routing third signals between third and fourth ones of the circuit components using the third metal layer.

12. The method of claim 8, wherein the FPA further comprises:

a plurality of insulating layers above the active circuit components and below the infrared sensors, wherein the circuit components, the first metal layer, the second metal layer, the third metal layer, and the infrared sensors are separated by corresponding ones of the insulating layers;

a first set of vias passing through a first one of the insulating layers to connect the first metal layer to the circuit components;

a second set of vias passing through a second one of the insulating layers to connect the second metal layer to the first metal layer;

a third set of vias passing through a third one of the insulating layers to connect the third metal layer to the second metal layer; and

a fourth set of vias passing through a fourth one of the insulating layers to connect the infrared sensors to the third metal layer.

13. The method of claim 8, wherein:

the infrared sensors are microbolometers;

a size of the array of infrared sensors is approximately 80 by 60; and

the FPA is part of an infrared imaging module adapted to be inserted into a socket having a size less than approximately 8.5 mm by 8.5 mm.

14. The method of claim 8, further comprising:

receiving an intentionally blurred image frame, wherein the blurred image frame comprises blurred thermal image data associated with the scene and noise introduced by an infrared imaging system;

processing the blurred image frame to determine a plurality of non-uniformity correction (NUC) terms to reduce at least a portion of the noise; and

applying the NUC terms to captured image frames.

15. A method of manufacturing a focal plane array (FPA) integrated circuit, the method comprising:

forming a plurality of active circuit components;

forming a plurality of insulating layers above the active circuit components;

forming first, second, and third metal layers above the active circuit components;

forming a plurality of infrared sensors above the metal layers and the insulating layers;

wherein the circuit components, the first metal layer, the second metal layer, the third metal layer, and the infrared sensors are separated by corresponding ones of the insulating layers;

wherein the first, second, and third metal layers are the only metal layers of the FPA between the infrared sensors and the circuit components; and

wherein the first, second, and third metal layers are adapted to route signals between the circuit components and the infrared sensors.

16. The method of claim 15, wherein:

the forming a plurality of active circuit components comprises forming a read out integrated circuit (ROIC) comprising a plurality of column amplifiers, a column multiplexer, and a row multiplexer;

the signals correspond to image frames captured by the infrared sensors; and

the first, second, and third metal layers are adapted to route the signals from the infrared sensors to the ROIC.

17. The method of claim 15, wherein:

the forming a plurality of active circuit components comprises;

forming a bias circuit adapted to provide a bias voltage in response to a regulated voltage selected from a range of approximately 1.5 volts to approximately 2.8 volts, and

forming a low-dropout regulator (LDO) adapted to provide the regulated voltage to the bias circuit in response to an external supply voltage selected from a range of approximately 2.8 volts to approximately 11 volts;

the signals comprise the bias voltage routed from the bias circuit to the infrared sensors through the first, second, and third metal layers.

18. The method of claim 15, wherein the circuit components comprise MOSFET transistors.

19. The method of claim 15, further comprising:

forming a first set of vias passing through a first one of the insulating layers to connect the first metal layer to the circuit components;

forming a second set of vias passing through a second one of the insulating layers to connect the second metal layer to the first metal layer;

forming a third set of vias passing through a third one of the insulating layers to connect the third metal layer to the second metal layer; and

forming a fourth set of vias passing through a fourth one of the insulating layers to connect the infrared sensors to the third metal layer.

20. The method of claim 15, wherein:

the infrared sensors are microbolometers;

a size of the array of infrared sensors is approximately 80 by 60; and

the FPA is a part of an infrared imaging module adapted to be inserted into a socket having a size less than approximately 8.5 mm by 8.5 mm.