During bottom filling of high aspect ratio gaps and trenches in an integrated circuit substrate using HDP-CVD, a pulsed HF bias is applied to the substrate. In some embodiments, pulsed HF bias is applied to the substrate during etching operations. The pulsed bias typically has a pulse frequency in a...http://www.google.com/patents/US7514375?utm_source=gb-gplus-sharePatent US7514375 - Pulsed bias having high pulse frequency for filling gaps with dielectric material
