IMAGE SENSOR

Disclosed is an image sensor including a first substrate that has a first surface and a second surface opposite to the first substrate and including a pixel array region and an edge region, an antireflection structure on the second surface, a pixel separation part in the first substrate and separating pixels from each other, and a microlens array on the antireflection structure. The antireflection structure includes a first dielectric layer, a titanium oxide layer, a second dielectric layer, and a third dielectric layer that are sequentially stacked. The first dielectric layer, the second dielectric layer, and the third dielectric layer include different materials from each other. On the edge region, the third dielectric layer penetrates the second dielectric layer and the titanium oxide layer to contact with the first dielectric layer.