Abstract: A semiconductor device having conductive paths separated by cavities is formed by depositing organic spin-on glass between the conductive paths, forming gaps between the organic spin-on glass and the conductive paths, and then removing the organic spin-on glass through the gaps. The gaps may be formed as a dummy pattern of via holes that are misaligned with the conductive paths, so that they extend past the upper surfaces of the conductive paths and form fine slits beside the conductive paths. This method of removing the spin-on glass leaves cavities that are free of unwanted oxide residue and debris, thereby minimizing the capacitive coupling between adjacent conductive paths.