Formation of embedded micro-lens

1. A semiconductor device, comprising:

a radiation-sensing element formed in a substrate;

a transparent layer formed over the substrate; and

a micro-lens embedded in the transparent layer and positioned to focus received radiation onto the radiation-sensing element situated beneath the micro-lens, wherein the micro-lens has a curved upper surface with an angular tip with a pointed profile.

2. The semiconductor device of claim 1 , further including:

a color filter layer formed over the transparent layer; and

a further micro-lens formed over the color filter layer.

3. The semiconductor device of claim 2 , wherein the micro-lens embedded in the transparent layer and the further micro-lens are substantially aligned.

4. The semiconductor device of claim 2 , wherein the micro-lens embedded in the transparent layer and the further micro-lens include different materials.

5. The semiconductor device of claim 4 , wherein the micro-lens embedded in the transparent layer includes a dielectric material, and the further micro-lens includes an organic material.

6. The semiconductor device of claim 1 , wherein the angular tip has an angle that is in a range from about 100 degrees to about 120 degrees.

7. The semiconductor device of claim 1 , wherein the semiconductor device is a front-side illuminated image sensor.

8. An image sensor device, comprising:

a pixel located in a substrate;

a first micro-lens embedded in a layer over the substrate, a first curved upper surface of the first micro-lens having an angular tip with a pointed profile;

a color filter located over the layer; and

a second micro-lens located over the color filter, a second upper surface of the second micro-lens having an approximately rounded profile;

wherein the pixel, the first micro-lens, the color filter, and the second micro-lens are all at least partially aligned with one another such that the first micro-lens focuses light onto the pixel.

9. The image sensor device of claim 8 , wherein the first and second micro-lenses are formed over the substrate in a vertical direction; and wherein the tip of the first micro-lens forms an angle with an imaginary line in a horizontal direction, the angle being between about 30 degrees and about 40 degrees.

10. The image sensor device of claim 8 , wherein:

the first micro-lens includes a dielectric material; and

the second micro-lens includes an organic material.

11. The image sensor device of claim 8 , wherein the image sensor device is a front-side illuminated image sensor.

12. A method, comprising:

forming a radiation-sensing element in a substrate;

forming a patterned dielectric layer over the substrate, the patterned dielectric layer including a plurality of dielectric portions separated by a plurality of openings; and

performing a laser annealing process on the patterned dielectric layer in a manner such that each of the dielectric portions are melted and re-shaped, the re-shaped dielectric portions each having a curved upper surface with an angular tip with a pointed profile.

13. The method of claim 12 , wherein the forming the patterned dielectric layer is carried out in a manner so that the dielectric portions each have a substantially rectangular shape before the performing the laser annealing process.

14. The method of claim 12 , wherein the dielectric portions each includes a silicon nitride material.

15. The method of claim 12 , further including, after the performing the laser annealing process:

forming a transparent material over the re-shaped dielectric portions;

planarizing the transparent material to form a transparent layer with the re-shaped dielectric portions embedded therein;

forming a color filter layer over the transparent layer; and

forming a plurality of micro-lenses over the color filter layer.

16. The method of claim 15 , wherein each of the micro-lenses is aligned with one of the re-shaped dielectric portions, the re-shaped dielectric portions each serving as an embedded micro-lens within the transparent layer.

17. The method of claim 12 , wherein the performing the laser annealing process is carried out in a manner so that the angular tip has an angle that is in a range from about 100 degrees to about 120 degrees.

18. The method of claim 12 , wherein the performing the laser annealing process is carried out using the following process parameters:

a laser source that is an ultra-violet light with a wavelength that is in a range from about 300 nanometers to about 600 nanometers;

an annealing duration that is in a range from about 150 nanoseconds to about 450 nanoseconds; and

an annealing energy that is in a range from about 0.5 mili-joules to about 2.5 mili-joules.

19. The method of claim 12 , wherein:

the forming the patterned dielectric layer is carried out in a manner so that each of the dielectric portions has a first width and a first height prior to being annealed; and

the performing the annealing process is carried out in a manner so that each of the re-shaped dielectric portions has a second width and a second height, the second width being approximately equal to the first width, and the second height being greater than the first height.

20. The method of claim 19 , wherein a ratio of the second height and the first height is in a range from about 1.5 to about 2.5.