Semiconductor device and manufacturing method thereof

A semiconductor device, comprising:

• a first dielectric layer disposed over a substrate;
• metal wirings embedded in the first dielectric layer, the metal wirings including a first metal wiring, a second metal wiring and a third metal wiring, all extending in a first direction and arranged in a second direction perpendicular to the first direction;
• a second dielectric layer disposed over the first dielectric layer and the metal wirings;
• an insulating layer disposed between the first dielectric layer and the second dielectric layer;
• and
• a first air gap formed between the first metal wiring and the second metal wiring and a second air gap formed between the second metal wiring and the third metal wiring, wherein:
• in a plan view, the insulating layer includes a first slit under which the first air gap is disposed and a second slit under which the second sir gap is disposed,
• the first and second slits have a width smaller than a space between adjacent two metal wirings in a second direction crossing the first direction, and
• upper surfaces of the first to third metal wirings are fully covered by the first insulating layer.

A semiconductor device, comprising:

• a first dielectric layer disposed over a substrate;
• metal wirings embedded in the first dielectric layer, the metal wirings including a first metal wiring, a second metal wiring and a third metal wiring, all extending in a first direction and arranged in a second direction perpendicular to the first direction;
• a second dielectric layer disposed over the first dielectric layer and the metal wirings;
• an insulating layer disposed between the first dielectric layer and the second dielectric layer;
• and
• a first air gap formed between the first metal wiring and the second metal wiring and a second air gap formed between the second metal wiring and the third metal wiring,
• parts of upper surface of the first and second metal wirings are covered by the insulating layer, and
• an upper surface of the second metal wiring has a region not covered by the insulating layer.