Image sensor device with high photosensitivity

• US 20090185275A1
• Filed: 01/18/2008
• Published: 07/23/2009
• Est. Priority Date: 01/18/2008
• Status: Active Grant

• Current Assignee: Visera Technologies Company Limited (Taiwan Semiconductor Manufacturing Company Limited)
• Original Assignee: Visera Technologies Company Limited (Taiwan Semiconductor Manufacturing Company Limited)
• Inventors: Pang, Chin-Poh, Liu, Wu-Chieh
• Granted Patent: US 8,213,085 B2
• Time in Patent Office: Days
• US Class Current: 359/586
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/24479 including variation in thickness

Abstract

An anti-reflection structure for transmitting a light source is disclosed. The anti-reflection structure comprises a first dielectric layer of a first refractive index and a second dielectric layer of a second refractive index different from the first refractive index. The first dielectric layer has a plurality of protrusions randomly arranged on a top surface thereof, in which the plurality of protrusions and the intervals therebetween has an average size smaller than the wavelength of the light source. The second dielectric layer has a bottom surface conformally attached to the top surface of the first dielectric layer. The invention also discloses an image sensor device having the anti-reflection structure.

Claims

1. An anti-reflection structure for transmitting a light source, comprising:

a first dielectric layer of a first refractive index, having a plurality of protrusions randomly arranged on a top surface thereof, wherein the plurality of protrusions and the intervals therebetween have an average size smaller than the wavelength of the light source; and

a second dielectric layer of a second refractive index different from the first refractive index, having a bottom surface conformally attached to the top surface of the first dielectric layer.

2. The anti-reflection structure as claimed in claim 1, wherein the first refractive index is greater than the second refractive index.

3. The image sensor device as claimed in claim 2, wherein the first dielectric layer is composed of silicon nitride and the second dielectric layer is composed of silicon oxide.

4. The anti-reflection structure as claimed in claim 1, wherein the second refractive index is greater than the first refractive index.

5. The anti-reflection structure as claimed in claim 4, wherein the second dielectric layer is composed of silicon nitride and the first dielectric layer is composed of silicon oxide.

6. The anti-reflection structure as claimed in claim 1, wherein the second dielectric layer has a plurality of protrusions randomly arranged on a top surface thereof, wherein the plurality of protrusions and the intervals therebetween have an average size smaller than the wavelength of the light source.

7. The anti-reflection structure as claimed in claim 6, further comprising a material layer of a third refractive index different from the second refractive index, having a bottom surface conformally attached to the top surface of the second dielectric layer.

8. An image sensor device, comprising:

a substrate having at least one photosensor therein for sensing a light source; and

an anti-reflection structure disposed on the substrate, comprising;

a first dielectric layer of a first refractive index, having a plurality of protrusions randomly arranged on a top surface thereof, wherein the plurality of protrusions and the intervals therebetween have an average size smaller than the wavelength of the light source; and

a second dielectric layer of a second refractive index different from the first refractive index, having a bottom surface conformally attached to the top surface of the first dielectric layer.

9. The image sensor device as claimed in claim 8, wherein the first refractive index is greater than the second refractive index.

10. The image sensor device as claimed in claim 9, wherein the first dielectric layer is composed of silicon nitride and the second dielectric layer is composed of silicon oxide.

11. The image sensor device as claimed in claim 8, wherein the second refractive index is greater than the first refractive index.

12. The image sensor device as claimed in claim 11, wherein the second dielectric layer is composed of silicon nitride and the first dielectric layer is composed of silicon oxide.

13. The image sensor device as claimed in claim 8, wherein the second dielectric layer has a plurality of protrusions randomly arranged on a top surface thereof, wherein the plurality of protrusions and the intervals therebetween have an average size smaller than the wavelength of the light source.

14. The image sensor device as claimed in claim 13, further comprising a material layer of a third refractive index different from the second refractive index, having a bottom surface conformally attached to the top surface of the second dielectric layer.