Image sensors with reduced stack height

A method of manufacturing an imaging system, comprising:

• forming an image sensor die by:
• forming a plurality of photodiodes in a substrate;
• forming a microlens array over the photodiodes;
• forming an external bond pad structure over the substrate;
• and
• simultaneously depositing a passivation layer directly on the microlens array and on the external bond pad structure.

A system, comprising:

• a signal processing unit;
• memory;
• a lens;
• input-output circuitry;
• and
• an imaging device that is stacked on the signal processing unit, wherein the imaging device comprises:
• a substrate having a front surface and a back surface;
• a plurality of imaging pixels formed in the front surface of the substrate;
• an array of microlenses formed over the imaging pixels and over the back surface of the substrate;
• a bond pad formed over the back surface of the substrate;
• and
• a passivation layer that is formed on the array of microlenses and on the bond pad.