Integrated circuit device and method for manufacturing same

An integrated circuit device, comprising:

• a substrate;
• a first insulating film provided on the substrate;
• a plurality of vias provided in the first insulating film and extending in a vertical direction;
• a second insulating film provided on the first insulating film, and having a composition different from a composition of the first insulating film;
• and
• a plurality of interconnects extending in a first direction crossing the vertical direction, being connected to the via, and having a lower portion disposed in the first insulating film, and an upper portion disposed in the second insulating film,
• an air gap being formed in the first insulating film and in the second insulating film, and also between the interconnects adjacent to each other, and a lower end of the air gap being located lower than lower surfaces of the interconnects.

A method for manufacturing an integrated circuit device, comprising:

• forming a second insulating film on a base body including a first insulating film, which is composed of a first insulating material, a first interconnect, which extends in a first direction, and in which a lower portion is disposed in the first insulating film, and an upper portion protrudes from an upper surface of the first insulating film, and a second interconnect, which extends in the first direction, and in which a lower portion is disposed in the first insulating film, and an upper portion protrudes from an upper surface of the first insulating film so that a space between the first interconnect and the second interconnect is not closed by depositing a second insulating material which is different from the first insulating material;
• locating a lower end of the space lower than a lower surface of the first interconnect and a lower surface of the second interconnect by performing etching under a condition that an etching speed for the first insulating material is higher than an etching speed for the second insulating material;
• and
• sealing an upper end of the space by depositing a third insulating material.