An image sensor may include a dielectric, a metal interconnection, an align key, a first substrate, a photodiode, and a transparent electrode. The first substrate may include a pixel region, a peripheral circuitry region and a scribe lane. The dielectric may include a metal interconnection and an align key over the first substrate. The photodiode may be formed over the pixel region and the scribe lane. The transparent electrode may be formed over the photodiode. The align key may have a protrusion formed in a center thereof.