A CMOS image sensor and a method for manufacturing the same are provided, in which a nitride layer for passivation is used as a microlens to reduce topology. The CMOS image sensor includes an upper metal layer partially deposited on a dielectric layer; a first nitride layer deposited on the upper metal layer; an undoped silicon glass layer deposited on the first nitride layer and polished by chemical-mechanical polishing; color filter array elements deposited and exposed on the undoped silicon glass layer and polished by the chemical-mechanical polishing; and a second nitride layer deposited on the first nitride layer and the color filter array elements and transfer-etched after forming a sacrificial microlens on the second nitride layer.