SYSTEM AND METHOD FOR ENHANCING LIGHT SENSITIVITY FOR BACKSIDE ILLUMINATION IMAGE SENSOR

• US 20080237761A1
• Filed: 04/02/2007
• Published: 10/02/2008
• Est. Priority Date: 04/02/2007
• Status: Abandoned Application

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Fu, Shih-Chi, Hsu, Tzu-Hsuan, Tsai, Chia-Shiung, Liu, Ming Chyi, Shiau, Gwo-Yuh, Shiu, Feng-Jia
• Application Number:
  US11/695,363
• Publication Number:
  US 20080237761A1
• Time in Patent Office: Days
• US Class Current: 257/432
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/1464 Back illuminated imager structures

Abstract

A system and method for enhancing light sensitivity of a back-side illumination image sensor are described. An integrated circuit includes a substrate and an image sensor device comprising at least one transistor formed over a first surface of the substrate and a photosensitive region. A color filter is disposed over a second surface of the substrate opposite the first surface thereof. A micro-lens structure is disposed between the second surface of the substrate and the color filter.

Claims

1. An integrated circuit comprising:

a substrate;

an image sensor device comprising at least one transistor formed over a first surface of the substrate and a photosensitive region;

a color filter disposed over a second surface of the substrate opposite the first surface thereof; and

a micro-lens structure disposed between the second surface of the substrate and the color filter.

2. The integrated circuit of claim 1 wherein the thickness of the substrate is between approximately 1.5 micrometers and approximately 10 micrometers.

3. The integrated circuit of claim 1 further comprising an insulating layer disposed between the second surface of the substrate and the micro-lens structure.

4. The integrated circuit of claim 1 further comprising a planarizing layer disposed between the micro-lens structure and the color filter.

5. The integrated circuit of claim 1 wherein the micro-lens structure has an n-value of less than or equal to approximately 2.0.

6. The integrated circuit of claim 1 wherein the photosensitive region has a doping depth greater than or equal to 1.0 micrometers.

7. An integrated circuit comprising:

a substrate;

an image sensor device comprising at least one transistor formed over a first surface of the substrate and a photosensitive region;

a first micro-lens structure formed over a second surface of the substrate opposite the first surface thereof;

a color filter disposed over first micro-lens structure; and

a second micro-lens structure formed over the color filter.

8. The integrated circuit of claim 7 wherein a thickness of the substrate is less than approximately 15 micrometers.

9. The integrated circuit of claim 7 wherein an n-value of the first micro-lens structure is greater than or equal to an n-value of the second micro-lens structure.

10. The integrated circuit of claim 7 wherein a radius of curvature of the first micro-lens structure is greater than or equal to a radius of curvature of the second micro-lens structure.

11. The integrated circuit of claim 7 wherein the first micro-lens structure comprises a first material and the second micro-lens structure comprises a second material and wherein the first and second materials are different.

12. The integrated circuit of claim 11 wherein the first material comprises a nitrogen-based material.

13. The integrated circuit of claim 11 wherein the second material comprises an organic material.

14. An integrated circuit comprising:

a substrate;

an image sensor device comprising at least one transistor formed over a first surface of the substrate and a photosensitive region;

a first micro-lens structure comprising a first material formed over a second surface of the substrate opposite the first surface thereof; and

a second micro-lens structure comprising a second material formed over the first micro-lens structure;

wherein the first material is different from the second material.

15. The integrated circuit of claim 14 wherein an n-value of the first micro-lens structure is greater than or equal to an n-value of the second micro-lens structure.

16. The integrated circuit of claim 14 wherein a radius of curvature of the first micro-lens structure is greater than or equal to a radius of curvature of the second micro-lens structure.

17. The integrated circuit of claim 14 further comprising a color filter disposed between the first micro-lens structure and the second micro-lens structure.

18. The integrated circuit of claim 14 wherein the first material comprises a nitrogen-based material and the second material comprises an organic material.

19. An integrated circuit comprising:

a substrate;

an image sensor device comprising at least one transistor formed over a first surface of the substrate and a photosensitive region;

a first micro-lens structure formed over a second surface of the substrate opposite the first surface thereof, the first micro-lens having a first n-value, a first curvature radius, and being formed of a first material; and

a second micro-lens structure formed over the first micro-lens structure, the second micro-lens having a second n-value, a second curvature radius, and being formed of a second material;

wherein at least one of either the first curvature radius, the first n-value, or the first material is different from at least one of the corresponding second curvature radius, second n-value, or second material.

20. The integrated circuit of claim 19 wherein the first n-value is greater than the second n-value and the first curvature radius is greater than the second curvature radius.