METHODS OF FORMING ANTI-REFLECTION STRUCTURES FOR CMOS IMAGE SENSORS Russian patent published in 2013 - IPC H01L31/112 

FIELD: physics.

SUBSTANCE: described is formation of protuberances (5) on an optical interface between two layers having different refraction indices, said protuberances having smaller vertical (h) and horizontal (p) dimensions than the wavelength of light detected by a photodiode (8). The protuberances can be formed by employing self-assembling block copolymers that form an array of sublithographic features of a first block copolymer component within a matrix of a second block copolymer component. The structure of the block copolymer component is transferred into a first optical layer (4) to form an array of nanoscale protuberances. Alternately, conventional lithography may be employed to form protuberances having dimensions smaller than the wavelength of light. A second optical layer is formed directly on the protuberances of the first optical layer. The interface between the first and second optical layers has a gradually variable refraction index and provides high transmission of light with little reflection.

EFFECT: forming structures which reduce reflection of light on the optical path of a CMOS image sensor pixel, thereby enhancing transmission of light to a photodiode and increasing the overall efficiency of the image sensor pixel.

35 cl, 37 dwg