A modified buffered-HF solution with NH4 F ： glycerol ： HF（4 ： 2 ： 1）is studied. With the implementation of a heating and agitating mechanism, this method is applied in a sacrificial layer etching scheme that increases the selectivity between silicon dioxide and aluminum. The etching rates of SiO2 and Al as a function of solution temperature are determined. Moreover,the effects of adding glycerol and agitating the etchant are examined and compared with this method. Finally, this method is tested on an actual device, and its efficiency is scrutinized.
