Method for manufacturing image sensor

Abstract

Methods of forming a microlens for an image sensor are provided. In one embodiment, the microlens can be oxide film microlens fabricated by forming an oxide film on a substrate; forming a first photoresist pattern on the oxide film; performing a plasma processing with respect to the oxide film using the first photoresist pattern as a mask; removing the first photoresist pattern; and performing an isotropic etching of the plasma processed oxide film. In another embodiment, the oxide film microlens can be fabricated by forming an oxide film on a substrate; forming a first photoresist pattern on the oxide film; implanting ions into the oxide film using the first photoresist pattern as a mask; removing the first photoresist pattern; and performing an isotropic etching of the ion implanted oxide film. Convex shaped microlens can be provided as a result of the etching selectivity to the oxide film.

1 . A method for manufacturing an image sensor, comprising:
 forming an oxide film on a substrate;   forming a first photoresist pattern on the oxide film exposing a first region of the oxide film;   performing a plasma process with respect to the oxide film using the first photoresist pattern as a mask;   removing the first photoresist pattern; and   performing an isotropic etching of the plasma processed oxide film to form an oxide film microlens.   
   
   
       2 . The method according to  claim 1 , wherein the first region of the oxide film comprises a portion of the oxide film corresponding to a central region of the oxide film microlens. 
   
   
       3 . The method according to  claim 2 , wherein the diameter of the central region is 20-50% of the diameter of the oxide film microlens. 
   
   
       4 . The method according to  claim 1 , wherein performing the plasma processing with respect to the oxide film comprises using physical vapor deposition equipment and conditions of Power: 200 W˜1500 W, N 2  Gas: 10˜60 sccm, N 2  Plasma Treatment Time: 10˜30 sec, and Pressure: 5˜10 mtorr. 
   
   
       5 . The method according to  claim 1 , wherein performing the plasma processing with respect to the oxide film comprises performing a nitrogen plasma process to form a nitride film on the first region of the oxide film. 
   
   
       6 . The method according to  claim 5 , wherein performing the isotropic etching comprises using an etching selectivity of the nitride film to the oxide film of 1:5˜6. 
   
   
       7 . The method according to claim.  1 , wherein performing the isotropic etching comprises using chemical vapor deposition equipment and conditions of Process Time: 60˜90 sec, and Pressure: 70˜100 mtorr. 
   
   
       8 . The method according to  claim 1 , further comprising:
 forming a protective layer on the substrate; and   forming a color filter layer on the protective layer, wherein the oxide film is formed after forming the color filter layer.   
   
   
       9 . A method for manufacturing an image sensor, comprising:
 forming an oxide film on a substrate;   forming a photoresist pattern on the oxide film to expose a first region of the oxide film;   implanting ions into the oxide film using the second photoresist pattern as a mask;   removing the second photoresist pattern; and   performing an isotropic etching of the ion implanted oxide film to form an oxide film microlens.   
   
   
       10 . The method according to  claim 9 , wherein the first region of the oxide film comprises a portion of the oxide film corresponding to an outer edge portion of the oxide film microlens. 
   
   
       11 . The method according to  claim 10 , wherein the outer edge portion is 10-30% of the radius of the oxide film microlens. 
   
   
       12 . The method according to  claim 9 , wherein implanting ions into the oxide film comprises implanting ions at an ion implantation energy of 10˜20 KeV and an angle of 0˜10°. 
   
   
       13 . The method according to  claim 9 , wherein implanting ions comprises using ions of an element having an atomic weight of at least 10. 
   
   
       14 . The method according to  claim 9 , wherein implanting ions comprises implanting germanium into the exposed oxide film. 
   
   
       15 . The method according to  claim 9 , wherein implanting ions into the oxide film comprises damaging the exposed oxide film with the implanted ions to form a damaged portion of the oxide film in the first region of the oxide film. 
   
   
       16 . The method according to  claim 15 , wherein performing the isotropic etching comprises using an etching selectivity of the damaged portion to the oxide film of 4˜5:1. 
   
   
       17 . The method according to  claim 9 , wherein performing the isotropic etching comprises using chemical vapor deposition equipment and conditions of Process Time: 60˜90 sec and Pressure: 70˜100 mtorr. 
   
   
       18 . The method according to  claim 9 , further comprising:
 forming a protective layer on the substrate; and   forming a color filter layer on the protective layer, wherein the oxide film is formed after forming the color filter layer.