Accoustic cleaning in nanoelectronics

The fabrication of state‐of‐the‐art electronic integrated circuits involves multiple cleaning steps in which residues of the order of ten or a few tens of nm need to be removed with very high efficiency. Historically cleaning was obtained by chemical undercutting (order of a few nm). The dimensions of nanoelectronic devices become so small that the amount of substrate etching involved in a cleaning step should be kept below 0.05 nm. Therefore other cleaning mechanism, involving a mechanical force, have to be considered such as acoustic agitation of the cleaning liquid or high‐velocity aerosol bombardment. These forces, however, can damage fine structures already fabricated on the substrate, particularly the “up‐features.” This implies that a trade‐off needs to be made between avoiding damage and obtaining an acceptable cleaning performance. This presentation includes typical hardware configurations and possible mechanisms for particle removal and use of megasonic agitation in nonaqueous liquid solutions.