A method of manufacturing a semiconductor device having damascene
structures with air gaps is provided. In one embodiment, the method
comprises providing a substantially planar layer having a first metal
layer, depositing a via level dielectric layer, patterning the via level
dielectric layer, at least partly etching the via level dielectric layer,
depositing a disposable layer on the at least partly etched via level
dielectric layer, patterning the disposable layer, depositing a second
metal layer, planarizing second metal layer, depositing permeable
dielectric layer after planarizing the second metal layer, and removing
the disposable layer through the permeable dielectric layer to form air
gaps.