Cost reduction and yield improvement by removing postash polymer residue from BEOL structures using inorganic chemicals

As finer architectures and higher aspect ratios result in the introduction of new materials, IC manufacturing processes must change to meet unprecedented higher requirements without adding cost and affecting throughput. This represents an enormous challenge to equipment design and chemical formulation development alike. Moreover, the transition to 300 mm wafer technology demands adaptation of 200-mm applications or even completely new process design. In the case of post-ash polymer removal in BEOL processing, a cost-effective approach applying novel inorganic mixtures on SEZ single-wafer tools has been found that enables shorter process times whilst ensuring wafer-to-wafer repeatability, low particle levels and even higher yields.