Patent ID: 7009772

Claim:
A semiconductor device comprising: a plurality of imaging sensors, each imaging sensor having a photosensitive area; a first layer formed over the plurality of imaging sensors, said first layer being substantially optically transparent; a first color filter layer formed on the first layer, said first color filter layer being registered with the photosensitive areas of a first subset of the plurality of imaging sensors; a second layer formed over the first color filter layer, said second layer comprising either a spacer layer or a second color filter layer, said second color filter layer being in mutual registration with a second subset of the plurality of imaging sensors; a third layer formed upon the second planarized layer, said third layer comprising either a spacer layer or a third color filter layer, said third color filter layer being in mutual registration with a third subset of the plurality of imaging sensors; a layer of patterned microlens material forming a first plurality of microlenses over the third layer, said first plurality of microlenses being mutually registered with the photosensitive areas of the plurality of imaging sensors; and an overcoat layer formed over the first plurality of microlenses, said overcoat layer having a graded refractive index profile such that a top portion of the overcoat layer has a first refractive index substantially the same as the refractive index of air and a bottom portion of the overcoat layer has a second refractive index substantially the same as a refractive index of at least one microlens of the first plurality of microlenses, the first and second refractive indexes being unequal.