Semiconductor device and method of manufacturing semiconductor device

A semiconductor device, comprising:

• a first substrate that includes a first circuit having a first function;
• a first inter-wiring insulating layer on the first substrate, wherein the first inter-wiring insulating layer includes a recess on a side opposite to the first substrate;
• a second inter-wiring insulating layer on the first inter-wiring insulating layer to cover the recess, wherein the second inter-wiring insulating layer includes a second wiring layer;
• a first wiring layer inside the recess in the first inter-wiring insulating layer;
• a gap around the first wiring layer, wherein the gap is between the first inter-wiring insulating layer and the second inter-wiring insulating layer;
• a second substrate that includes a second circuit having a second function, wherein the second function of the second circuit is different from the first function of the first circuit;
• and
• a multi-layer wiring layer on the second substrate, wherein
• the multi-layer wiring layer opposes the second inter-wiring insulating layer,
• the multi-layer wiring layer includes:
• a fourth inter-wiring insulating layer;
• and
• a fourth wiring layer in the fourth inter-wiring insulating layer, wherein the fourth wiring layer is electrically coupled to the second wiring layer.