Image sensor

An image sensor, comprising:

• a first substrate that has a first surface and a second surface opposite to the first surface, and that includes a pixel array area and an edge area;
• an anti-reflection structure on the second surface;
• a pixel isolator on the first substrate defining and separating pixels;
• a color filter on the anti-reflection structure;
• a micro lens array on the color filter;
• a first interlayer insulating layer on the first surface of the first substrate;
• a first wire within the first interlayer insulating layer;
• a second interlayer insulating layer under the first interlayer insulating layer;
• a second wire within the second interlayer insulating layer;
• a second substrate under the second interlayer insulating layer;
• a contact on the second surface of the first substrate in the edge area;
• a conductive pad on the second surface of the first substrate in the edge area and at a position farther from the pixel array area than the contact;
• and
• a first via and a second via, the first via and the second via partially passing through the first substrate, the first interlayer insulating layer, and the second interlayer insulating layer in the edge area, and contact at least one of the first wire and the second wire,
• wherein the anti-reflection structure includes a first insulating layer, a titanium oxide layer, a second insulating layer, and a third insulating layer sequentially stacked, and
• an edge of the titanium oxide layer is between the contact and the conductive pad, and the titanium oxide layer is electrically connected to the contact.

An image sensor, comprising:

• a first substrate that has a first surface and a second surface opposite to the first surface, and that includes a pixel array area and an edge area;
• an anti-reflection structure on the second surface;
• a pixel isolator on the first substrate defining and separating pixels;
• a color filter on the anti-reflection structure;
• a micro lens array on the color filter;
• a first interlayer insulating layer on the first surface of the first substrate;
• a first wire within the first interlayer insulating layer;
• a second interlayer insulating layer under the first interlayer insulating layer;
• a second wire within the second interlayer insulating layer;
• a second substrate under the second interlayer insulating layer;
• and
• a first conductive pad and a second conductive pad that are on the second surface of the first substrate in the edge area,
• wherein the anti-reflection structure includes a first insulating layer, a titanium oxide layer, a second insulating layer, and a third insulating layer sequentially stacked,
• the titanium oxide layer includes a main body part having an edge between the pixel array area and the first conductive pad and a connection part connecting between the main body part and the second conductive pad, and
• the connection part is electrically connected to the second conductive pad.