CMOS image sensor and method for manufacturing the same

1. A CMOS image sensor comprising:

a semiconductor substrate;

a plurality of photodiodes arranged on the semiconductor substrate with a predetermined distance therebetween;

an inter-insulation layer formed on the overall surface of the semiconductor substrate including the photodiodes;

a plurality of color filter layers arranged on the inter-insulation layer with a predetermined distance therebetween;

a planarization layer formed on the overall surface of the semiconductor substrate including the color filter layers;

a plurality of first micro-lenses formed in upper part of the planarization layer, each of the first micro-lenses arranged over a corresponding photodiode, respectively; and

a plurality of second micro-lenses formed on the planarization layer, each of the plurality of second micro-lenses wrapping a corresponding first micro-lens respectively.

2. The sensor as set forth in claim 1 , wherein the first micro-lenses protrude from the surface of the planarization layer.

3. The sensor as set forth in claim 1 , wherein each of the first micro-lenses has a width narrower than that of a corresponding color filter array.

4. The sensor as set forth in claim 1 , wherein the first and second micro-lenses are made of different materials having different refraction indexes from each other.

5. The sensor as set forth in claim 4 , wherein the first and second micro-lenses are made of SiON and photoresist respectively.

6. The sensor as set forth in claim 4 , wherein the first and second micro-lenses are made of SiO 2 and photoresist respectively.

7. The sensor as set forth in claim 4 , wherein the first and second micro-lenses are both photoresist materials, wherein the first micro-lens has an index of refraction that is smaller than the index of refraction of the second micro-lens.

8. A CMOS image sensor comprising:

a plurality of first micro-lenses formed in upper part of the planarization layer, each of the first micro-lenses arranged over a corresponding photodiode; and

a plurality of second micro-lenses formed on the planarization layer, each of the plurality of second micro-lenses wrapping a corresponding first micro-lens respectively;

wherein the index of refraction of the first micro-lenses is smaller than the index of refraction of the second micro-lenses.

9. A method for manufacturing a CMOS image sensor comprising the steps of:

forming an inter-insulation layer over a semiconductor substrate;

forming a plurality of color filter layers on the inter-insulation to be arranged with a predetermined distance therebetween;

forming a planarization layer on the overall surface of the semiconductor substrate including the color filter layers;

forming a plurality of trenches having a predetermined depth in upper part of the planarization layer to correspond to the photodiodes in a one-to-one ratio;

forming first micro-lenses in the trenches, respectively; and

forming second micro-lenses on the planarization layer to wrap the first micro-lenses, respectively.

10. The method as set forth in claim 9 , wherein the first and second micro-lenses are made of different materials having different refraction indexes from each other.

11. The method as set forth in claim 9 , wherein the step of forming the second micro-lenses comprises:

coating a lens forming material layer on the, overall surface of the semiconductor substrate including the first micro-lenses; and

selectively patterning the lens forming material layer.

12. The method as set forth in claim 11 , wherein the step of forming the second micro-lenses further comprises performing a reflow process of the patterned lens-forming material layer.

13. The method as set forth in claim 9 , further comprising the step of curing the second micro-lenses.

14. The method as set forth in claim 13 , wherein the step of curing the second micro-lenses comprises irradiating ultraviolet rays onto the second micro-lenses.