Patent ID: 7183195

Claim:
A method of fabricating dual damascene interconnections, the method comprising: (a) forming on a substrate an organo silicate glass layer having a dielectric constant of 3.3 or less; (b) forming a via in the organo silicate glass layer; (c) filling the via formed in the organo silicate glass layer with a carbon-free inorganic filler, the carbon-free inorganic filler extending laterally beyond top edges of the via; (d) processing the surface of the carbon-free inorganic filler filling the via formed in the organo silicate glass layer using plasma; (e) forming a photoresist pattern on the inorganic filler filling the via and extending laterally beyond the top edges of the via to define a trench; (f) after forming the photoresist pattern, partially etching the inorganic filler filling the via and extending laterally beyond the top edges of the via and the organo silicate glass layer to form the trench, which is connected to the via and in which interconnections will be formed; (g) removing the inorganic filler remaining in the via; and (h) completing interconnections by filling the trench and the via with interconnection material.