Patent ID: 7427528

Claim:
A method for fabricating a CMOS image sensor having a plurality of active devices for receiving each of a corresponding plurality of bands of incident light according to wavelength, the method comprising: forming a field oxide layer over a semiconductor substrate; forming over the semiconductor substrate an active region for each band of incident light; forming a dielectric interlayer covering each active region over the semiconductor substrate; forming a color filter layer on the dielectric interlayer, the color filter layer having an interlaced plurality of color filters corresponding to the respective formations of each active region; forming a planarization layer on the color filter layer; and forming, on the planarization layer, a microlens above each color filter of the color filter layer; wherein each active region has a predetermined depth relative to each band of incident light and such that there is at least one active region having a lesser depth than the field oxide layer; wherein the plurality of color filters includes a red filter, a green filter, and a blue filter; wherein each active region is formed as a series of first, second, and third photodiodes corresponding to the blue filter, the green filter, and the red filter, respectively; wherein forming the active region comprises: depositing a first photoresist film over the semiconductor substrate and patterning the first photoresist film to define respective regions for the first, second and third photodiodes; implanting impurity ions, at a first ion implantation energy, into each of the respective regions using the patterned first photoresist film as a mask to form the first photodiode; depositing a second photoresist film over the semiconductor substrate and patterning the second photoresist film to expose only the second and third photodiode regions; implanting impurity ions, at a second ion implantation energy, into each of the exposed second and third photodiode regions using the patterned second photoresist film as a mask to form the second photodiode; depositing a third photoresist film over the semiconductor substrate and patterning the third photoresist film to expose only the third photodiode region; and implanting impurity ions, at a third ion implantation energy, into the exposed third photodiode region using the patterned third photoresist film as a mask to form the third photodiode.