Evaluation of ALE processes for patterning

Abstract

The need for continued device scaling along with the increasing demand for high precision have lead to the development of atomic layer etch processes in semiconductor manufacturing. We have tested this new methodology with regard to patterning applications. While these new plasma-enhanced atomic layer etch (PE-ALE) processes show encouraging results, most patterning applications are best realized by optimizations through discharge chemistry and/or plasma parameters. While PE-ALE approaches seem to have limited success for trilayer patterning applications, significant improvements were obtained when applying them to small pitch. In particular the increased selectivity to OPL seems to offer a potential benefit for patterning high aspect ratio features.

Utilizing surface modification in plasma‐enhanced cyclic etching of tantalum nitride to surpass lithographic limits

“…Overall, ALE processes offer a significantly higher degree of tunability over traditional continuous‐wave (CW) plasma etching, due to the fact that parameters such as gas flows, pressure, and bias power can be adjusted on a step‐specific basis rather than as a global setting for the length of the process. ALE has been studied for a variety of blanket films ranging from semiconductors to dielectrics to metals, however, the number of papers in the literature that have discussed its applications to patterned profiles is significantly fewer …”

High-Definition Nanoimprint Stamp Fabrication by Atomic Layer Etching

“…Here, the ALE process can improve NIL stamp fabrication by providing atomic-scale control. Use of the ALE process in patterning high-aspect-ratio features with narrow pitch sizes has been reported lately. ,, Because the ALE process is not perturbed by surface loading, patterns with different geometries are expected to be processed identically provided saturation of surface coverage is reached. Hence, designing a combination of micro- and nanostructured features on the same nanoimprint stamp is possible by employing the ALE process.…”