METHOD OF MAKING A DEEP JUNCTION FOR ELECTRICAL CROSSTALK REDUCTION OF AN IMAGE SENSOR

• US 20080014673A1
• Filed: 07/10/2006
• Published: 01/17/2008
• Est. Priority Date: 07/10/2006
• Status: Active Grant

• Current Assignee: Advanced Manufacturing Innovations Incorporated
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: CHIANG, Shang-Yi, YAUNG, Dun-Nian, WUU, Shou-Gwo, WANG, Chung
• Granted Patent: US 7,791,170 B2
• Time in Patent Office: Days
• US Class Current: 438/57
• CPC Class Codes: H01L 27/14623 Optical shielding
• CPC Class Codes: H01L 27/14627 Microlenses
• 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 27/148 Charge coupled imagers individual charge coupled devices H01L29/765

Abstract

The present disclosure provides an image sensor semiconductor device. The semiconductor device includes a substrate having a front surface and a back surface; a plurality of sensor elements formed on the front surface of the substrate, each of the plurality of sensor elements configured to receive light directed towards the back surface; and an aluminum doped feature formed in the substrate and disposed horizontally between two adjacent elements of the plurality of sensor elements and vertically between the back surface and the plurality of sensor elements.

Claims

1. An image sensor semiconductor device, comprising:

a substrate having a front surface and a back surface;

a plurality of sensor elements formed on the front surface of the substrate, each of the plurality of sensor elements configured to receive light directed towards the back surface; and

an aluminum doped feature formed in the substrate and disposed horizontally between two adjacent elements of the plurality of sensor elements and vertically between the back surface and the plurality of sensor elements.

2. The device of claim 1, wherein the aluminum doped feature comprises a depth/width ratio greater than about 3.

3. The device of claim 1, wherein the substrate comprises a crystalline silicon configured in one of <

100> and

<

111>

orientation.

4. The device of claim 1, wherein the aluminum doped feature comprises a height greater than about 1 micron.

5. The device of claim 1, wherein the aluminum doped feature comprises an aluminum doping concentration ranging between about 10¹³ atoms/cm³ and 10²⁰ atoms/cm³.

6. The device of claim 1, wherein each of the plurality of sensor elements is selected from the group consisting of complementary metal-oxide-semiconductor (CMOS) image sensor, charge-coupled device sensor, active pixel sensor, passive pixel sensor, and combinations thereof.

7. An image sensor semiconductor device, comprising:

a sensor element formed in a semiconductor substrate;

an inter-level dielectric (ILD) formed in the semiconductor substrate;

conductive features disposed in the ILD; and

an junction of aluminum dopants formed in the ILD and disposed horizontally around the sensor element in a top view of the semiconductor substrate.

8. The device of claim 7, wherein the junction comprises a depth greater than 1 micron.

9. The device of claim 7, wherein the junction of aluminum dopants comprises a doping profile with a ratio of depth/width greater than about 3.

10. The device of claim 7, wherein the junction of aluminum dopants comprises an aluminum doping concentration ranging between about 10¹³ atoms/cm³ and 10²⁰ atoms/cm³.

11. A method of fabricating a semiconductor device, comprising:

providing a semiconductor substrate;

forming a masking layer on the semiconductor substrate;

forming an opening in the masking layer, the opening configured to expose the semiconductor substrate within the opening;

forming an aluminum-containing layer on the masking layer and on the semiconductor substrate within the opening; and

driving aluminum from the aluminum-containing layer into the semiconductor substrate through the opening of the masking layer to form a junction of aluminum dopants around the sensor element.

12. The method of claim 11, further comprising removing the aluminum-containing layer after the driving of aluminum.

13. The method of claim 11, wherein the driving of aluminum comprises an annealing process.

14. The method of claim 13, wherein the driving of aluminum comprises an annealing temperature ranging between about 400°

C. and 1200°

C.

15. The method of claim 13, wherein the annealing process is selected from the group consisting of a thermal annealing, a flash annealing, a laser annealing, and a combination thereof.

16. The method of claim 11, wherein the forming of the masking layer comprises forming the masking layer using a method selected from the group consisting of thermal oxidation, thermal nitridation, chemical vapor deposition, physical vapor deposition, spin-on coating, and combinations thereof.

17. The method of claim 11, wherein the forming of the aluminum-containing layer comprises utilizing a method selected from the group consisting of chemical vapor deposition, physical vapor deposition, plating, and combinations thereof.

18. The method of claim 11, wherein the forming of the opening comprises utilizing an etching process.