Granted Patent B2

US 8,698,925 · App. 12/764,862 · Granted Apr 15, 2014

Abstract

Claims (49)

1. An image sensor comprising:

a solid state semiconductor imager comprising a backside thinned pixel array sensor and having a passivated silicon surface wherein a portion of the passivated silicon surface includes a pixel array region, having a plurality of pixels;

a silicon collimator having each elemental collimator aligned with a pixel sub-array; and

a metal bond inside the pixel array region joining the passivated silicon surface of the solid state semiconductor imager to the silicon collimator; and

wherein the metal bond comprises a plurality of metal bonds interspersed on the passivated silicon surface inside the pixel array region between the pixel sub-arrays;

wherein the metal bonds do not exceed 50% pixel coverage of a single pixel.

2. The image sensor of claim 1 , wherein the metal bond comprises a thermo-compressioned metallized catch pad and metal layer.

3. The image sensor of claim 1 , wherein the metal bond comprises a brazed metallized catch pad and metal layer.

4. The image sensor of claim 1 , further comprising plurality of metal bonds interspersed outside of the pixel array region.

5. The image sensor of claim 1 , wherein each of the individual metal bonds comprises a line segment aligned at a 45 degree angle to the pixel array.

6. The image sensor of claim 1 , wherein one individual metal bond is provided for every four pixels.

7. The image sensor of claim 4 , wherein the individual metal bonds interspersed on the passivated silicon surface inside the pixel array comprise barrier layer and the metal bonds interspersed outside of the pixel array region do not include barrier layer.

8. The image sensor of claim 1 , wherein the metal bond comprises a gold-to-gold thermo-compression bond.

9. An image sensor comprising:

a solid state semiconductor imager comprising a sensor anode and having a pixel array region with a plurality of pixels and a plurality of metallized catch pads interspersed inside the pixel array region among the plurality of pixels; and

a collimator having a metallized layer that faces the sensor anode, the metallized layer joined to the metallized catch pad to form a metal bond

wherein the metal bonds do not exceed 50 % pixel coverage of a single pixel.

10. The image sensor of claim 9 , wherein each of the metallized catch pads comprises a top metal layer, an adhesion layer and a barrier layer.

11. The image sensor of claim 9 , wherein each of the metallized catch pads comprises a top metal layer and a barrier layer.

12. The image sensor of claim 9 , wherein each of the metallized catch pads comprises a gold layer, a titanium layer and a SiO x N y layer.

13. The image sensor of claim 9 , wherein the collimator further comprises an adhesion layer between a collimator body of the collimator and the metallized layer.

14. The image sensor of claim 9 , further comprising plurality of metallized catch pads positioned outside of the pixel array region.

15. The image sensor of claim 9 , wherein the solid state semiconductor imager is a backside thinned pixel array sensor having a passivated surface.

16. The image sensor of claim 9 , wherein the metal bond is formed by a thermo-compression process.

17. The image sensor of claim 9 , wherein the metal bond is formed by a brazing process.

18. The image sensor of claim 9 , wherein each of the metallized catch pads comprises a top metal layer and an adhesion layer and some of the metallized catch pads also comprise a barrier layer, wherein a subset of the catch pads lack the barrier so that a path is provided to assure that the collimator remains at electrical potential of the sensor anode.

19. The image sensor of claim 9 , wherein the metal bond comprises a gold-to-gold thermo-compression bond.

20. The image sensor of claim 9 , wherein each of the plurality of metallized catch pads comprises a line segment aligned at a 45 degree angle to the pixel array.

21. The image sensor of claim 9 , wherein the plurality of metallized catch pads comprises one individual metal bond provided for every four pixels.

22. A method of making an image sensor comprising:

aligning a collimator with a solid state semiconductor imager, wherein the imager comprises a passivated silicon surface with a pixel array region having a plurality of pixels;

forming a plurality of catch pads interspaced among the plurality of pixels within the pixel array region;

metalizing bottom surface of the collimator; and

joining the bottom surface of the collimator with the plurality of catch pads of the solid state semiconductor imager to form a metal bond between the collimator and the solid state semiconductor imager, the metal bond positioned inside the pixel array region of the solid state semiconductor imager; and wherein the metal bonds do not exceed 50% pixel coverage of a single pixel.

23. The method of claim 22 wherein joining the collimator with the solid state semiconductor imager to form the metal bond comprises performing a thermo-compression process.

24. The method of claim 22 wherein joining the collimator with the solid state semiconductor imager to form the metal bond comprises performing a brazing process.

25. The method of claim 22 wherein joining the collimator with the solid state semiconductor imager to form the metal bond comprises performing a soldering process.

26. The method of claim 22 , wherein forming a plurality of catch pads comprises:

depositing a barrier layer on the solid state semiconductor imager;

depositing an adhesion layer on the barrier layer; and

depositing a top metal layer on the adhesion layer.

27. The method of claim 22 , wherein metalizing the bottom surface of the collimator comprises:

depositing an adhesion layer on the bottom surface of the collimator; and

depositing a bottom metal layer on the adhesion layer.

28. The method of claim 23 wherein one metallic catch pad is provided for each pixel sub-array.

29. The method of claim 22 , wherein joining the collimator with the solid state semiconductor imager to form the metal bond comprises forming a gold-to-gold thermo-compression bond.

30. The method of claim 22 , wherein joining the collimator with the solid state semiconductor imager to form the metal bond comprises heating the collimator with the solid state semiconductor imager to 300° C. and applying pressure.

31. The method of claim 22 , wherein forming a plurality of catch pads comprises forming line segments aligned at a 45 degree angle to the pixel array.

32. The method of claim 22 , wherein forming a plurality of catch pads comprises forming one individual metal bond for every four pixels.

Assignments (9)