Air gap formation method for reducing undesired capacitive coupling between interconnects in an integrated circuit device

A method for forming an air gap structure in an integrated circuit, the method comprising:

• forming a device layer;
• and
• forming at least a first dielectric layer on the device layer;
• and
• patterning said at least first dielectric layer to form first openings therein;
• and
• forming at least a first aluminum based conductive layer on the at least first dielectric layer and so as to fill said first openings therein;
• and
• removing a part of said at least a first aluminum based conductive layer to form a first aluminum based interconnect structure of first aluminum based conductive lines;
• and
• forming at least a second dielectric layer on the first aluminum based interconnect structure of first aluminum based conductive lines;
• forming second openings in said second dielectric layer;
• and
• forming a second aluminum based interconnect structure of second aluminum based conductive lines on said at least second dielectric layer, said second aluminum based interconnect structure also filling said second openings to form contacts to said first aluminum based interconnect structure;
• forming at least one third opening which extends from said second aluminum based interconnect structure to said first aluminum based interconnect structure;
• and
• forming a third dielectric layer over said third opening to form at least one multi-level air gap that is situated between adjacently located aluminum based conductive lines in said second aluminum based interconnect structure of second aluminum based conductive lines;
• wherein said at least one multi-level air gap operates to isolate adjacently located aluminum based interconnect conductive lines in at least two separate aluminum based interconnect levels located at different distances from said device layer, including in said first aluminum based interconnect structure and said second aluminum based interconnect structure.