Image sensor including auto-focus pixels

Abstract

An image sensor includes a normal pixel, a first auto-focus (AF) pixel, and a second AF pixel, each of the normal pixel, the first AF pixel and the second AF pixel including a photodiode. The image sensor further includes a normal microlens disposed on the normal pixel, and a first AF microlens disposed on the first AF pixel and the second AF pixel. The photodiode of the normal pixel, the photodiode of the first AF pixel, and the photodiode of the second AF pixel are respectively disposed in photo-detecting areas of a semiconductor substrate. A height of the first AF microlens in a vertical direction from a top surface of the semiconductor substrate is greater than a height of the normal microlens in the vertical direction from the top surface of the semiconductor substrate.

What is claimed is: 
     
         1 . An image sensor comprising:
 a normal pixel, a first auto-focus (AF) pixel, and a second AF pixel, each of the normal pixel, the first AF pixel and the second AF pixel comprising a photodiode;   a normal microlens disposed on the normal pixel; and   a first AF microlens disposed on the first AF pixel and the second AF pixel,   wherein the photodiode of the normal pixel, the photodiode of the first AF pixel, and the photodiode of the second AF pixel are respectively disposed in photo-detecting areas of a semiconductor substrate, and   wherein a height of the first AF microlens in a vertical direction from a top surface of the semiconductor substrate is greater than a height of the normal microlens in the vertical direction from the top surface of the semiconductor substrate.   
     
     
         2 . The image sensor of  claim 1 , wherein the first AF pixel is adjacent to the second AF pixel in a horizontal direction parallel to the top surface of the semiconductor substrate. 
     
     
         3 . The image sensor of  claim 1 , wherein the first AF microlens has a first width in a first horizontal direction parallel to the top surface of the semiconductor substrate, the first width being greater than a second width in a second horizontal direction parallel to the top surface of the semiconductor substrate. 
     
     
         4 . The image sensor of  claim 1 , further comprising:
 a third AF pixel and a fourth AF pixel, each of the third AF pixel and the fourth AF pixel comprising a photodiode; and   a second AF microlens disposed on the third AF pixel and the fourth AF pixel,   wherein a height of the second AF microlens in the vertical direction from the top surface of the semiconductor substrate is greater than the height of the normal microlens in the vertical direction from the top surface of the semiconductor substrate, and   wherein the first AF pixel is adjacent to the third AF pixel in a horizontal direction parallel to the top surface of the semiconductor substrate.   
     
     
         5 . The image sensor of  claim 1 , further comprising a protection layer disposed on the normal microlens and the first AF microlens. 
     
     
         6 . The image sensor of  claim 1 , wherein the normal microlens and the first AF microlens continuously comprise a same material. 
     
     
         7 . The image sensor of  claim 1 , further comprising a deep trench isolation portion (DTI) separating the photo-detecting areas from one another,
 wherein the DTI is disposed to extend from a bottom surface of the semiconductor substrate to the top surface of the semiconductor substrate.   
     
     
         8 . The image sensor of  claim 7 , wherein the normal microlens and the first AF microlens are disposed on the top surface of the semiconductor substrate, and
 wherein a first width of a first cross-section in which the DTI contacts the bottom surface of the semiconductor substrate is greater than a second width of a second cross-section in which the DTI contacts the top surface of the semiconductor substrate.   
     
     
         9 . The image sensor of  claim 1 , further comprising same color filters disposed on the first AF pixel and the second AF pixel. 
     
     
         10 . The image sensor of  claim 9 , wherein the same color filters comprises green filters or white filters. 
     
     
         11 . An image sensor comprising:
 a pixel array comprising a plurality of pixels arranged in a first direction and a second direction perpendicular to the first direction,   wherein the plurality of pixels comprises:
 normal pixels; 
 a first auto-focus (AF) pixel; 
 a second AF pixel adjacent to the first AF pixel in the first direction; 
   a first AF microlens disposed on the first AF pixel and the second AF pixel; and   normal microlenses respectively disposed on the normal pixels,   wherein a vertical height of the first AF microlens is greater than a vertical height of the normal microlenses.   
     
     
         12 . The image sensor of  claim 11 , further comprising same color filters disposed on first through fourth pixels arranged in two columns adjacent to each other and two rows adjacent to each other, among the normal pixels. 
     
     
         13 . The image sensor of  claim 12 , wherein the first through fourth pixels comprise respective photodiodes connected to one floating diffusion area. 
     
     
         14 . The image sensor of  claim 11 , further comprising same color filters disposed on first through ninth pixels arranged in three columns adjacent to one another and three rows adjacent to one another, among the normal pixels. 
     
     
         15 . The image sensor of  claim 11 , wherein the first AF pixel is disposed adjacent to the normal pixel in the second direction and a direction opposite the second direction. 
     
     
         16 . The image sensor of  claim 11 , wherein the plurality of pixels further comprises:
 a third AF pixel; and   a fourth AF pixel, each of the third AF pixel and the fourth AF pixel comprising a photodiode,   wherein the image sensor further comprises a second AF microlens disposed on the third AF pixel and the fourth AF pixel,   wherein a vertical height of the second AF microlens is greater than the vertical height of the normal microlens, and   wherein the first AF pixel is adjacent to the third AF pixel in the second direction.   
     
     
         17 . The image sensor of  claim 11 , wherein the first AF microlens has a first width in the first direction is greater than a second width in the second direction. 
     
     
         18 . The image sensor of  claim 11 , wherein the normal microlens and the first AF microlens continuously comprise a same material. 
     
     
         19 . The image sensor of  claim 11 , further comprising same color filters are disposed on the first AF pixel and the second AF pixel. 
     
     
         20 . An image sensor comprising:
 photo-detecting areas, in which photodiodes are respectively disposed;   color filters disposed on the photo-detecting areas; and   a normal microlens and an auto-focus (AF) microlens that are disposed on the color filters,   wherein the normal microlens corresponds to one among the photo-detecting areas,   wherein the AF microlens corresponds to two among the photo-detecting areas, and   wherein a vertical height of the AF microlens is greater than a vertical height of the normal microlens.