Color Filter Array and Micro-Lens Structure for Imaging System

Abstract

A color filter array and micro-lens structure for imaging system and method of forming the color filter array and micro-lens structure. A micro-lens material is used to fill the space between the color filters to re-direct incident radiation, and form a micro-lens structure above a top surface of the color filters.

1 . An imaging device comprising:
 a first color filter element on a semiconductor substrate;   a second color filter element on the semiconductor substrate and spaced apart from the first color filter element;   a micro-lens structure arranged over a top surface of the first color filter element; and   a sidewall waveguide structure arranged between neighboring sidewalls of the first and second color filter elements, the sidewall waveguide structure and micro-lens structure being made of the same material.   
     
     
         2 . The imaging device of  claim 1 , the material of the micro-lens structure and the sidewall waveguide structure being transparent and having an index of refraction which is lower than that of the first color filter element. 
     
     
         3 . The imaging device of  claim 1 , wherein the material of the sidewall waveguide structure and the micro-lens structure is photo resist or oxide and has an index of refraction that is between 1.1 and 1.8. 
     
     
         4 . The imaging device of  claim 1 , further comprising:
 a first photodetector arranged under the first color filter element; and   a second photodetector arranged under the second color filter element;   the micro-lens structure being configured to focus both a first incident ray, which has a first angle of incidence that is less than a predetermined angle of incidence, and a second incident ray, which has a second angle of incidence that is greater than the predetermined angle of incidence, through the first color filter element, and   the sidewall waveguide structure being configured to reflect the focused first incident ray to strike the first photodetector and further configured to refract the focused second incident ray to pass between the first and second photodetectors.   
     
     
         5 . A semiconductor imaging system comprising:
 a photodetector array including a matrix of individual photodetectors;   a color filter array arranged over the photodetector array and including a matrix of color filter elements which are arranged vertically over respective photodetectors in the photodetector array;   an array of micro-lenses arranged over the color filter array and including a matrix of micro-lens structures which are arranged vertically over respective color filter elements of the color filter array; and   a sidewall waveguide structure laterally surrounding a color filter element and configured to re-direct incident radiation striking a micro-lens structure with a first angle of incidence, which is less than a predetermined angle of incidence, toward an individual photodetector that corresponds vertically to the color filter element and the micro-lens structure.   
     
     
         6 . The semiconductor imaging system of  claim 5 , the sidewall waveguide structure being further configured to re-direct incident radiation striking the micro-lens structure with a second angle of incidence, which is greater than the predetermined angle of incidence, to pass between neighboring photodetectors. 
     
     
         7 . The semiconductor imaging system of  claim 5 , wherein the sidewall waveguide structure has a first index of refraction, the micro-lens structure has a second, different index of refraction, and the color filter element has a third index of refraction that is larger than the first index of refraction and larger than the second index of refraction. 
     
     
         8 . The semiconductor imaging system of  claim 5 , wherein the sidewall waveguide structure and the micro-lens structure are made of the same material. 
     
     
         9 . The semiconductor imaging system of  claim 8 , wherein the material of the sidewall waveguide structure and the micro-lens structure is photoresist or oxide and has an index of refraction that is between 1.1 and 1.8. 
     
     
         10 . The semiconductor imaging system of  claim 5 , wherein the color filter array comprises primary color filter elements arranged in a matrix. 
     
     
         11 . The semiconductor imaging system of  claim 10 , wherein the primary color filter elements include a red color filter, a green color filter, and a blue color filter. 
     
     
         12 . The semiconductor imaging system of  claim 5 , wherein the individual photodetectors are made of a silicon-containing material. 
     
     
         13 . The semiconductor imaging system of  claim 5 , wherein the color filter element is made of photoresist and has an index of refraction that is between 1.6 and 2.0. 
     
     
         14 . The semiconductor imaging system of  claim 5 , wherein a ratio of a height of a color filter element to a space between neighboring color filter elements is about 1:7. 
     
     
         15 . The semiconductor imaging system of  claim 5 , wherein the individual photodetectors are complementary metal-oxide-semiconductor (CMOS) photodetectors. 
     
     
         16 - 20 . (canceled) 
     
     
         21 . An imaging device disposed over a semiconductor substrate comprising:
 first and second photodetectors arranged at least partially in the semiconductor substrate;   first and second color filter elements disposed above the first and second photodetectors, respectively;   first and second micro-lens structures covering top surfaces of the first and second color filter elements, respectively; and   a sidewall waveguide structure separating the first and second color filter elements;   wherein the sidewall waveguide structure has an index of refraction that is smaller than that of the first and second color filter elements.   
     
     
         22 . The imaging device of  claim 21 , wherein the material of the sidewall waveguide structure is photoresist. 
     
     
         23 . The imaging device of  claim 21 , wherein the material of the sidewall waveguide structure is silicon dioxide. 
     
     
         24 . The imaging device of  claim 21 , wherein the sidewall waveguide structure has an index of refraction that is between 1.1 and 1.8. 
     
     
         25 . The imaging device of  claim 21 , wherein the sidewall waveguide structure and the first and second micro-lens structures are made of the same material.