ALD/ALE 2021 Session ALE8: Integration of ALD + ALE

Nanofabrication is facing multiple challenges, such as patterning limits and transition to 3D structures, with the downscaling of devices to sub-5nm scale. To overcome the existing challenges, area-selective atomic layer deposition (AS-ALD) has surfaced as a promising candidate for a toolbox of nanofabrication. In our previous work, we introduced a Si precursor type inhibitor using bis(methylamino)dimethylsilane (DMADMS) and it showed reliable AS-ALD with high process compatibility with current unit processes of nanofabrication. In this work, the AS-ALD is extended to a multipurpose process that DMADMS is used as a Si inhibitor as well as precursor for SiO₂ ALD using ozone as an oxidant. In addition, AS-ALD Ru process is also integrated into the SiO₂ process as a supporting layer for oxidation protection and lateral growth control. In a detailed process, the experiments are designed in such a way that DMADMS inhibitor is first adsorbed selectively on SiO₂ surface. After DMADMS inhibitor adsorption, Ru AS-ALD process is carried out and Ru is selectively deposited on Cu surface only, given that DMADMS can efficiently block Ru ALD. In the following process, SiO₂ AS-ALD process is performed by oxidizing DMADMS inhibitor by ozone counter reactant. A SiO₂ film nucleates solely on SiO₂ surface, while ozone etches out the AS-ALD Ru from the Cu surface simultaneously. In this way, self-aligned nanopatterns can be formed without additional plasma dry etching processes and photolithography. This combined atomic layer processing is believed to be an example to show effective integration and applicability of AS-ALD into the current nanofabrication technology.