Formation of embedded micro-lens

• US 8,610,227 B2
• Filed: 10/13/2010
• Issued: 12/17/2013
• Est. Priority Date: 10/13/2010
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Chou, Shih Pei, Liu, Shih-Chang, Tu, Yeur-Luen, Tsai, Chia-Shiung
• Primary Examiner(s): Toledo, Fernando L
• Assistant Examiner(s): KUSUMAKAR, KAREN M
• Application Number:
  US12/903,871
• Publication Number:
  US 20120091549A1
• Time in Patent Office: 1,161 Days
• Field of Search: 438 57- 98, 257431-466
• US Class Current: 257/432
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements

Abstract

Provided is an image sensor device. The image sensor device includes a pixel formed in a substrate. The image sensor device includes a first micro-lens embedded in a transparent layer over the substrate. The first micro-lens has a first upper surface that has an angular tip. The image sensor device includes a color filter that is located over the transparent layer. The image sensor device includes a second micro-lens that is formed over the color filter. The second micro-lens has a second upper surface that has an approximately rounded profile. The pixel, the first micro-lens, the color filter, and the second micro-lens are all at least partially aligned with one another in a vertical direction.

Claims

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.