Semiconductor device and manufacturing method thereof

A method for manufacturing a semiconductor device, comprising:

• forming metal wirings embedded in a 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;
• forming a first insulating layer over the metal wirings and the first dielectric layer;
• forming a first mask pattern over the first insulating layer, the first mask pattern including a first opening and a second opening, both extending in the first direction and having a first width in the second direction, respectively, the first opening being separated from the second opening;
• reducing the width of the first opening and the second opening, thereby forming a second mask pattern having a third opening and a fourth opening, with a second width smaller than the first width, respectively;
• patterning the first insulating layer by using the second mask as an etching mask, thereby forming a fifth opening and a sixth opening in the first insulating layer corresponding to the third opening and the fourth opening, respectively;
• forming a first groove corresponding to the fifth opening between the first metal wiring and the second metal wiring and a second groove corresponding to the sixth opening between the second metal wiring and the third metal wiring by etching the first dielectric layer through the fifth and sixth openings;
• and
• forming a second dielectric layer so that a first air gap is formed in the first groove and a second air gap is formed in the second groove,
• wherein a width of the fifth opening in the second direction is smaller than a space between the first metal wiring and the second metal wiring in the second direction.

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 upper surfaces of the first to third metal wirings are fully covered by the first insulating layer and are not in contact with the second dielectric layer.