Semiconductor image sensor

A back side illumination (BSI) image sensor comprising:

• a substrate comprising a front side and a back side opposite to the front side;
• and
• a plurality of pixel sensors arranged in an array, and each of the pixel sensors comprising:
• a photo-sensing device in the substrate;
• a color filter over the photo-sensing device on the back side;
• and
• an optical structure over the color filter, wherein the optical structure comprises a first sidewall, the first sidewall and a plane substantially parallel with a front surface of the substrate form an included angle greater than 0°, and the optical structure includes a vertex disposed directly over the photo-sensing device.

A back side illumination (BSI) image sensor comprising:

• a substrate comprising a front side and a back side opposite to the front side;
• a pixel sensor in the substrate;
• a color filter over the substrate on the back side;
• a plurality of micro-lenses over the color filter,
• wherein a bottom area of each of the micro-lenses is less than a top area of the color filter, a sum of the bottom areas of the plurality of micro-lenses is greater than the top area of the color filter, and each micro-lens overlaps a portion of the color filter.