Optical micro structure, method for fabricating the same and applications thereof

Abstract

An image sensor comprises a plurality of color filtering elements, a plurality of lenses and an image sensing device, wherein the lenses are correspondingly formed over the color filtering elements, and the image sensing device having a sensing area engaged with the color filtering elements.

1 . An image sensor, comprising:
 a plurality of color filtering elements;   a plurality of lenses correspondingly formed over the color filtering elements; and   an image sensing device having a sensing area engaged with the color filtering elements.   
     
     
         2 . The image sensor of  claim 1 , wherein the color filtering elements are buried in a dielectric layer of the sensing area and with a deepness extending beyond a bottom metal which is disposed in the dielectric layer and adjacent to the sensing area. 
     
     
         3 . The image sensor of  claim 1 , further comprising a planarization layer disposed between the plurality of lenses and the plurality of color filtering elements. 
     
     
         4 . The image sensor of  claim 1 , wherein the color filtering elements are contiguously disposed on a backside of the image sensing device. 
     
     
         5 . The image sensor of  claim 1 , wherein the image sensor has a wafer-scale structure which can be cut into a plurality of image sensing chips. 
     
     
         6 . The image sensor of  claim 1 , further comprising:
 a working substrate; and   a transparent substrate disposed on the working substrate, wherein the transparent substrate has a plurality of recesses allowing the lenses correspondingly embedded in the recesses.   
     
     
         7 . The image sensor of  claim 1 , wherein the image sensor further comprises a passive layer disposed on the transparent substrate opposite to the lenses. 
     
     
         8 . A method for fabricating an image sensor, comprising:
 forming a transparent substrate on a working substrate;   forming pluralities of micro lens in the transparent substrate, wherein the lenses have a refraction ratio differing from that of the transparent substrate;   forming a color filter on the lenses; and   engaging the color filter with an image sensing device by flipping the working substrate.   
     
     
         9 . The method for fabricating the image sensor of  claim 8 , wherein the engagement of the color filter and the image sensing device comprises steps of:
 forming a concave portion in the sensing area; and   contiguously disposing the color filter to a bottom of the concave portion.   
     
     
         10 . The method for fabricating the image sensor of  claim 8 , wherein the engagement of the color filter and the image sensing device comprises steps of disposing the color filter contiguously to a backside of the image sensing device. 
     
     
         11 . The method for fabricating the image sensor of  claim 8 , wherein the formation of the color filter comprises steps of forming a plurality of color filtering elements over and corresponding to the lenses. 
     
     
         12 . The method for fabricating the image sensor of  claim 8 , wherein the formation of the color filter comprises steps of forming a planarization layer overlying the lenses, and forming a plurality of color filtering elements overlying the planarization layer. 
     
     
         13 . The method for fabricating the image sensor of  claim 8 , further comprising planarizing the working substrate, whereby the remaining working substrate can serve as a passive layer to protect the color filter, after the color filter is engaged with the image sensing device. 
     
     
         14 . The method for fabricating the image sensor of  claim 8 , wherein after the color filter is engaged with the image sensing device, further comprising
 removing the working substrate; and   forming a passive layer on the transparent substrate opposite to the lenses.   
     
     
         15 . A method for fabricating an image sensor, comprising:
 providing a color filter wafer having a plurality of color filters;   providing an image sensor wafer having a plurality of image sensing devices, wherein each of the image sensing device has a sensing area corresponding to one of the color filters; and   engaging the color filter wafer with the image sensor wafer to make each of the color filter buried in a dielectric layer of the sensing area with a deepness extending beyond a bottom metal disposed in the dielectric layer and adjacent to the sensing area.   
     
     
         16 . The method for fabricating the image sensor of  claim 15 , wherein after the color filter wafer and the image sensor wafer are engaged, a wafer sawing process is carried out to cut the engaged color filter wafer and the image sensor wafer into a plurality of image sensing chips each at least comprises one of the micro lens, one of the image sensing devices and one of the color filters.