Several techniques are described for modulating the etch rate of a sacrificial light absorbing material (SLAM) by altering its composition so that it matches the etch rate of a surrounding dielectric. This is particularly useful in a dual damascene process where the SLAM fills a via opening and is etched...http://www.google.com/patents/US7101798?utm_source=gb-gplus-sharePatent US7101798 - Method to modulate etch rate in SLAM
