Patent ID: 6821810
Filing Date: 2004-11-23
Classification: H01L

Abstract:
A method of fabricating a semiconductor color imager having an optical structure wherein an overcoat layer is adapted for optimizing long focal length microlens performance in an ordered process sequence comprising:a semiconductor substrate having a matrix of imaging sensors formed thereon each imaging sensor having a photosensitive area and a complementary non-photosensitive area, said matrix of imaging sensors being organized in a plurality of subsets; forming a matrix of light shields over the non-photosensitive areas of the matrix of imaging sensors; forming a first passivation layer over the matrix of imaging sensors; forming a first optically transparent planarization layer over the first passivation layer over the matrix of imaging sensors; forming a first patterned color filter layer on the first optically transparent planarization layer, said first patterned color filter layer being registered with the photosensitive areas of a first subset of the matrix of imaging sensors; forming upon the first patterned color filter layer a second planarizing and/or patterend color filter layer in mutual registration with the first color filter layer and a with subset of photosensitive areas (color pixels); forming upon the second planarizing and/or color filter layer a third planarizing and/or color filter layer in mutual registration with the first end second color filter layers and a subset of photosensitive areas (color pixels; patterning a layer of microlens material to form a first matrix of microlenses over the third planarizing and/or color filter layer, said first matrix of microlenses being mutually registered with the photosensitive areas in the matrix of imaging sensors; forming an overcoat layer over the first matrix of microlenses, said overcoat layer having high transmittance, said overcoat layer providing patterned or uniform optical compensation between the subsets of the matrix of the imaging sensors; whereby said optical structure provides flexibility in design and optimized performance in a single color or a muiltiple color semiconductor imager.