Solid-state imaging device and method for manufacturing the same

Abstract

A solid state imaging device includes a substrate having a plurality of pixels and a plurality of on-chip lenses arranged above the substrate, each on-chip lens having a lens surface formed by subjecting a transparent photosensitive film to exposure using a mask having a gradation pattern and development so that the lens surface serves to correct shading in accordance with the gradation pattern.

What is claimed: 
     
         1 . A method of manufacturing a solid-state imaging device, comprising the steps of:
 forming a semiconductor substrate;   forming a pixel unit having a plurality of pixels in the substrate; and   forming a lens unit having a plurality of on-chip lenses on the substrate by a mask pattern including light transparent sections and nontransparent sections.   
     
     
         2 . The method according to  claim 1 , wherein the mask pattern is a fine binary pattern. 
     
     
         3 . The method according to  claim 2 , wherein the fine binary pattern is represented by a transmitted light intensity distribution which is varied in each lens by continuously varying the ratio of the area of the nontransparent sections to the area of the transparent sections. 
     
     
         4 . The method according to  claim 1 , wherein the mask pattern has a gradation pattern. 
     
     
         5 . The method according to  claim 4 , wherein the on-chip lens has a shading-corrected lens surface by the gradation pattern of the mask pattern. 
     
     
         6 . The method according to  claim 5 , wherein the mask pattern has a minimum transparent ratio by a part of an amount of sag which is at a minimum. 
     
     
         7 . The method according to  claim 6 , wherein the amount of sag is defined by a surface function of the surface lens. 
     
     
         8 . The method according to  claim 1 , wherein the mask pattern is one-dimensional gray scale pattern. 
     
     
         9 . The method according to  claim 1 , wherein the mask pattern is two-dimensional gray scale pattern. 
     
     
         10 . The method according to  claim 1 , wherein the mask pattern is a binary gray-tone mask. 
     
     
         11 . The method according to  claim 10 , wherein the binary gray-tone mask is formed by varying a transmitted light intensity distribution according to an image height. 
     
     
         12 . A solid-state imaging device, comprising:
 a semiconductor substrate;   a pixel unit having a plurality of pixels in the substrate; and   a lens unit having a plurality of on-chip lenses on the substrate being formed by a mask pattern including light transparent sections and nontransparent sections.   
     
     
         13 . The solid-state imaging device according to  claim 12 , wherein the mask pattern is a fine binary pattern. 
     
     
         14 . The solid-state imaging device according to  claim 13 , wherein the fine binary pattern is represented by a transmitted light intensity distribution which is varied in each lens by continuously varying the ratio of the area of the nontransparent sections to the area of the transparent sections. 
     
     
         15 . The solid-state imaging device according to  claim 12 , wherein the mask pattern has a gradation pattern. 
     
     
         16 . The solid-state imaging device according to  claim 15 , wherein the on-chip lens has a shading-corrected lens surface by the gradation pattern of the mask pattern. 
     
     
         17 . The solid-state imaging device according to  claim 16 , wherein the mask pattern has a minimum transparent ratio by a part of an amount of sag which is at a minimum. 
     
     
         18 . The solid-state imaging device according to  claim 17 , wherein the amount of sag is defined by a surface function of the surface lens. 
     
     
         19 . The solid-state imaging device according to  claim 12 , wherein the mask pattern is one-dimensional gray scale pattern. 
     
     
         20 . The solid-state imaging device according to  claim 12 , wherein the mask pattern is two-dimensional gray scale pattern. 
     
     
         21 . The solid-state imaging device according to  claim 12 , wherein the mask pattern is a binary gray-tone mask. 
     
     
         22 . The solid-state imaging device according to  claim 21 , wherein the binary gray-tone mask is formed by varying a transmitted light intensity distribution in accordance with an image height.