Image Sensor and Method for Manufacturing the Same

• US 20090096050A1
• Filed: 10/09/2008
• Published: 04/16/2009
• Est. Priority Date: 10/11/2007
• Status: Active Grant

• Current Assignee: MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management)
• Original Assignee: Dongbu HiTek Co., Ltd. (DB HiTek Co., Ltd.)
• Inventors: PARK, Seung Ryong
• Granted Patent: US 8,049,289 B2
• Time in Patent Office: Days
• 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

Disclosed are an image sensor and a method for manufacturing the same. The image sensor includes a semiconductor substrate including a unit pixel, first to third color filters provided on the semiconductor substrate, a first micro-lens provided on each of the first and third color filters, and a second micro-lens provided on the second color filter, in which an outer periphery of the first micro-lens has a square shape, and an upper portion of the first micro-lens has a semi-spherical or convex shape.

Claims

1. An image sensor comprising:

a semiconductor substrate including a plurality of unit pixels;

first to third color filters on or over the semiconductor substrate;

first micro-lenses on the first and third color filters; and

second micro-lenses on the second color filters, in which an outer periphery of each first micro-lens has a square shape, and an upper portion of each first micro-lens has a semi-spherical or convex shape.

2. The image sensor of claim 1, wherein the outer periphery of the second micro-lenses has a circular shape.

3. The image sensor of claim 1, wherein the first color filter includes a red color filter, the second color filter includes a green color filter, and the third color filter includes a blue color filter.

4. The image sensor of claim 1, wherein the second color filter is at opposite sides of the first color filter and/or the third color filter.

5. A method for manufacturing an image sensor, the method comprising the steps of:

forming a plurality of unit pixels on a semiconductor substrate;

forming first to third color filters on or over the semiconductor substrate;

forming first micro-lenses on the first and third color filters; and

forming second micro-lenses on the second color filter, wherein an outer periphery of the first micro-lenses has a square shape, and an upper portion of the first micro-lenses has a semi-spherical or convex shape.

6. The method of claim 5, wherein the first color filter includes a red color filter, the second color filter includes a green color filter, and the third color filter includes a blue color filter.

7. The method of claim 5, wherein the step of forming the first micro-lenses includes the steps of:

forming a first seed pattern on the first and third color filters;

forming a first lens pattern having the semi-spherical or convex shape and a greater width than a width of the first color filter or the second color filter by performing a reflow process on the first seed pattern; and

removing a side or edge surface or portion of the first lens pattern such that the first lens pattern has an area substantially identical to an area of the first color filter and/or the third color filter.

8. The method of claim 7, wherein the step of removing the side or edge surface or portion of the first lens pattern includes forming a photoresist pattern at a position corresponding to the first color filter and/or the third color filter, and thereafter, a step of etching the first lens pattern using a photoresist pattern as a mask.

9. The method of claim 5, wherein the step of forming the second micro-lenses includes the steps of:

forming a second seed pattern on the second color filter; and

performing a reflow process on the second seed pattern.

10. The method of claim 5, wherein the first micro-lenses are protected by a protective mask while the second micro-lenses are being formed.

11. An image sensor comprising:

a semiconductor substrate including a plurality of unit pixels;

first to third color filters on the semiconductor substrate corresponding to the unit pixels;

first micro-lenses on the first color filter and the third color filter;

a second micro-lens on the second color filter; and

a coating pattern on a surface of at least one of the color filters,

wherein an upper surface of the first and second micro-lenses has a convex or semi-spherical shape, and the first and/or second micro-lenses have a square-shaped periphery.

12. The image sensor of claim 11, wherein the coating pattern includes a hydrophobic material.

13. The image sensor of claim 11, wherein the second color filter is at opposite sides of the first color filter and/or the third color filter.

14. A method for manufacturing an image sensor, the method comprising the steps of:

forming a plurality of unit pixels on a semiconductor substrate;

forming a color filter array including first to third color filters on the semiconductor substrate, each color filter corresponding to one of the unit pixels;

forming micro-lenses on the second color filter, the micro-lenses having a spherical or convex top surface and a square-shaped outer periphery;

forming a coating pattern on the surface of the micro-lenses; and

forming additional micro-lenses on the first color filter and the third color filter, the additional micro-lenses having a spherical or convex top surface and a square-shaped outer periphery.

15. The method of claim 14, wherein the step of forming the micro-lenses and the coating pattern includes the steps of:

forming a seed pattern by coating a material for a lens on the second color filter and patterning the material;

forming a lens pattern having a semi-spherical or convex shape and a width greater than the second color filter, by performing a reflow process on the second seed pattern;

forming a coating layer on the color filter array including the second lens pattern;

forming a photoresist pattern on the coating layer corresponding to a shape and a position of the second color filter; and

removing a coating layer and the second lens pattern on a remaining area except for an upper portion of the second color filter using the photoresist pattern as an etching mask.

16. The method of claim 14, wherein the step of forming the micro-lenses includes the steps of:

forming a first seed pattern on the first color filter and the third color filter; and

performing a reflow process on the first seed pattern,

wherein an upper surface of the micro-lenses has a spherical surface from the coating pattern when a reflow process is performed on the first seed pattern.

17. The method of claim 14, wherein the coating pattern includes a hydrophobic material.

18. The method of claim 15, wherein a circular mask is used when the second seed pattern is formed.