Image sensor

An image sensor comprising:

• a first substrate;
• a first wiring structure disposed on the first substrate, the first wiring structure including a first interlayer insulating layer and a first wiring layer disposed inside the first interlayer insulating layer;
• a second wiring structure disposed on the first wiring structure and including a second wiring layer;
• a second substrate disposed on the second wiring structure, the second substrate including a first region and a second region that are spaced apart from each other, the first region including a photoelectric conversion element disposed therein;
• a connection trench penetrating the second region of the second substrate, extending into the first wiring layer, and exposing at least a partial portion of the second wiring layer;
• and
• a conductive pattern disposed along a sidewall and a bottom surface of the connection trench, the conductive pattern including a first portion directly contacting a top surface of the first wiring layer and a second portion directly contacting a top surface of the second wiring layer,
• wherein the first portion of the conductive pattern includes a first bottom surface disposed inside the first wiring layer and a second bottom surface having a height difference from the first bottom surface.

An image sensor comprising:

• a first substrate;
• a first wiring structure disposed on the first substrate and including a first wiring layer;
• a second wiring structure disposed on the first wiring structure and including a second wiring layer;
• a second substrate disposed on the second wiring structure and including a first region and a second region that are spaced apart from each other, the first region including a photoelectric conversion element disposed therein;
• and
• a connection trench penetrating the second region of the second substrate and exposing each of the first wiring layer and the second wiring layer;
• and
• a conductive pattern disposed along a sidewall and a bottom surface of the connection trench, and having a step in the bottom surface of the connection trench exposing the first wiring layer,
• wherein the conductive pattern includes a first bottom surface that is a lowermost surface of the conductive pattern and a second bottom surface having a height difference from the first bottom surface, and
• wherein the first bottom surface of the conductive pattern is disposed at a higher level than a level of the bottom surface of the first wiring layer.