Semiconductor device including via plug

A semiconductor device, comprising:

• a lower insulating layer on a lower substrate;
• a lower pad structure inside the lower insulating layer;
• an upper insulating layer on the lower insulating layer;
• an upper pad structure inside the upper insulating layer and adjacent to the lower pad structure;
• an upper substrate on the upper insulating layer;
• and
• a via plug overlapping the upper pad structure and the lower pad structure, wherein the upper pad structure includes a plurality of upper pad conductive layers and an upper connection layer formed between the plurality of upper pad conductive layers, wherein the upper connection layer includes a conductive pattern having a shape different from that of at least one of the upper pad conductive layers, and wherein the via plug overlaps the upper connection layer.

A semiconductor device, comprising:

• a lower insulating layer on a lower substrate;
• a lower pad structure inside the lower insulating layer;
• an upper insulating layer on the lower insulating layer;
• an upper pad structure inside the upper insulating layer;
• an upper substrate having a cell region and a via region on the upper insulating layer;
• a photodiode inside the upper substrate in the cell region;
• and
• a via plug passing through at least a portion of each of the upper substrate, the upper insulating layer, and the lower insulating layer in the via region, the via plug in contact with the upper pad structure and the lower pad structure, wherein:
• the upper pad structure includes a plurality of upper pad conductive layers and an upper connection layer between the plurality of upper pad conductive layers,
• the upper connection layer includes a conductive pattern having a shape different from a shape of at least one of the upper pad conductive layers, and
• the via plug is in direct contact with the upper pad conductive layers and the upper connection layer.