Image sensor including auto-focus pixels

1 . A method of manufacturing an image sensor, comprising:

arranging a plurality of photo-detecting areas corresponding to each of a plurality of pixels including a normal pixel, a first auto-focus (AF) pixel, and a second AF pixel on a first surface of a semiconductor substrate;

disposing an insulating layer and color filters on a second surface of the semiconductor substrate;

disposing a lens layer on the color filters, the lens layer having a lower surface facing the color filters and an upper surface opposite the lower surface, and the lens layer being continuously formed of a same material from the lower surface to the upper surface;

disposing a first photoresist film on the upper surface of the lens layer;

performing a first etching process on the lens layer and a first dummy lens to form a first micro lens pattern in the lens layer, the first dummy lens being formed based on the first photoresist film, the first micro lens pattern having a first etched upper surface opposite the lower surface of the lens layer, and the same material being continuously formed from the lower surface to the first etched upper surface;

disposing a second photoresist film on the first etched upper surface of the first micro lens pattern; and

performing a second etching process on the first micro lens pattern and a second dummy lens to form a micro lens, the second dummy lens being formed based on the second photo resist film, the micro lens having a second etched upper surface opposite the lower surface of the lens layer, and the same material being continuously formed from the lower surface to the second etched upper surface.

2 . The method of claim 1 , wherein the arranging the plurality of photo-detecting areas comprises:

forming a deep trench isolation portion to isolate the plurality of photo-detecting areas from each other.

3 . The method of claim 2 , wherein the deep trench isolation portion is formed to extend from the first surface to the second surface.

4 . The method of claim 3 , wherein a width of the deep trench isolation portion formed on the first surface is greater than a width of the deep trench isolation portion formed on the second surface.

5 . The method of claim 2 , wherein the forming the deep trench isolation portion comprises:

constructing the deep trench isolation portion with an insulating material having a lower refractive index than the semiconductor substrate.

6 . The method of claim 1 , wherein the disposing the first photoresist film comprises:

disposing the first photoresist film such that a common pattern is formed on the first AF pixel and the second AF pixel.

7 . The method of claim 6 , wherein the second photoresist film is formed on the first AF pixel and the second AF pixel, and not on the normal pixel.

8 . The method of claim 6 , wherein a height of the micro lens formed corresponding to the first AF pixel and the second AF pixel is greater than a height of the micro lens formed corresponding to the normal pixel.

9 . The method of claim 1 , wherein the forming the first micro lens pattern comprises:

forming the first dummy lens by performing a reflow process on the first photoresist film,

wherein the first dummy lens is formed in a convex hemisphere shape.

10 . The method of claim 1 , wherein the forming the micro lens comprises:

forming the second dummy lens by performing a reflow process on the second photoresist film, and

wherein the second dummy lens is formed in a convex hemisphere shape.

11 . The method of claim 1 , wherein each of patterns of the first photoresist film is formed to have a constant distance from each other.

12 . The method of claim 1 , wherein the first etching process and the second etching process are wet etching processes using the first dummy lens and the second dummy lens as an etch mask, respectively.

13 . The method of claim 1 , further comprising depositing a protective film on the micro lens.

14 . The method of claim 1 , wherein a same color filter is disposed on the first AF pixel and the second AF pixel.

15 . The method of claim 1 , wherein the first surface is a bottom surface of the semiconductor substrate, the second surface is a top surface of the semiconductor substrate.

16 . A method of manufacturing an image sensor, comprising:

arranging a plurality of photo-detecting areas corresponding to each of a plurality of pixels including a normal pixel, a first auto-focus (AF) pixel, and a second AF pixel on a bottom surface of a semiconductor substrate;

disposing a lens layer on a top surface of the semiconductor substrate, the lens layer having a lower surface facing the semiconductor substrate and an upper surface opposite the lower surface, and the lens layer being continuously formed of a same material from the lower surface to the upper surface;

disposing a first photoresist film on the upper surface of the lens layer such that a common pattern is formed on the first AF pixel and the second AF pixel;

forming a first dummy lens by processing the first photoresist film;

forming a first micro lens pattern in the lens layer by etching the lens layer and the first dummy lens, the first micro lens pattern having a first etched upper surface opposite the lower surface of the lens layer, and the same material being continuously formed from the lower surface to the first etched upper surface;

disposing a second photoresist film on the first etched upper surface of the first micro lens pattern;

forming a second dummy lens by processing the second photoresist film; and

forming a micro lens by etching the first micro lens pattern and the second dummy lens, the micro lens having a second etched upper surface opposite the lower surface of the lens layer, and the same material being continuously formed from the lower surface to the second etched upper surface.

17 . The method of claim 16 , wherein the arranging the plurality of photo-detecting areas comprises:

forming a deep trench isolation portion to isolate the plurality of photo-detecting areas from each other.

18 . The method of claim 16 , wherein the second photoresist film is formed on the first AF pixel and the second AF pixel, and not on the normal pixel.

19 . A method of manufacturing an image sensor, comprising:

arranging a plurality of photo-detecting areas corresponding to each of a plurality of pixels including a normal pixel, a first auto-focus (AF) pixel, and a second AF pixel, and isolated from each other by a deep trench isolation portion;

disposing an insulating layer and a plurality of color filters on the plurality of photo-detecting areas;

disposing a lens layer on the plurality of color filters, the lens layer having a lower surface facing the plurality of color filters and an upper surface opposite the lower surface, and the lens layer being continuously formed of a same material from the lower surface to the upper surface;

disposing a first photoresist film on the upper surface of the lens layer;

forming a first dummy lens by processing the first photoresist film;

forming a first micro lens pattern by etching the lens layer and the first dummy lens, the first micro lens pattern having a first etched upper surface opposite the lower surface of the lens layer, and the same material being continuously formed from the lower surface to the first etched upper surface;

disposing a second photoresist film corresponding to the first AF pixel and the second AF pixel on the first etched upper surface of the first micro lens pattern;

forming a second dummy lens by processing the second photoresist film; and

forming a micro lens by etching the first micro lens pattern and the second dummy lens, the micro lens having a second etched upper surface opposite the lower surface of the lens layer, and the same material being continuously formed from the lower surface to the second etched upper surface.

20 . The method of claim 19 , wherein the disposing the first photoresist film comprises:

disposing the first photoresist film such that a common pattern is formed on the first AF pixel and the second AF pixel, and is offset from the normal pixel.