Print Email Facebook Twitter Insight into the removal and reapplication of small inhibitor molecules during area-selective atomic layer deposition of SiO2 Title Insight into the removal and reapplication of small inhibitor molecules during area-selective atomic layer deposition of SiO2 Author Merkx, M.J.M. Jongen, R.G.J. Mameli, A. Lemaire, P.C. Sharma, K. Hausmann, D.M. Kessels, W.M.M. Mackus, A.J.M. Publication year 2021 Abstract As the semiconductor industry progresses toward more complex multilayered devices with ever smaller features, accurately aligning these layers with respect to each other has become a bottleneck in the advancement to smaller transistor nodes. To avoid alignment issues, area-selective atomic layer deposition (ALD) can be employed to deposit material in a self-aligned fashion. Previously, we demonstrated area-selective ALD of SiO2 using three-step (i.e., ABC-type) ALD cycles comprising an acetylacetone (Hacac) dose (step A), a bis(diethylamino) silane precursor dose (step B), and an O2 plasma exposure (step C). In this work, the mechanisms of the removal and reapplication of the inhibitor molecules during area-selective ALD were studied, with the aim of enhancing the selectivity of the process. In situ infrared spectroscopy shows that the O2 plasma exposure does not completely remove the adsorbed Hacac species (i.e., acac adsorbates) at the end of the cycle. The persisting species were found to contain fragments of Hacac molecules, which hinder subsequent inhibitor adsorption in the next ALD cycle, and thereby contribute to a loss in selectivity. Alternatively, it was found that an H2 plasma is able to completely remove all acac species from the surface. An improvement in selectivity was achieved by using a four-step ALD cycle that includes an H2 plasma step, allowing the nucleation delay to be prolonged from 18 ± 2 to 30 ± 3 ALD cycles. As a result, 2.7 ± 0.3 nm SiO2 can be deposited with a selectivity of 0.9, whereas only 1.6 ± 0.2 nm can be achieved without the H2 plasma step. This work shows that the addition of a dedicated inhibitor removal step before the reapplication of the inhibitors can significantly improve the selectivity. Subject AcetoneInfrared spectroscopyMoleculesSemiconductor device manufactureSemiconductor devicesSilicaSiliconArea selectiveInhibitor moleculesMultilayered devicesPlasma exposureSemiconductor industrySilane precursorSitu infrared spectroscopyTransistor nodesAtomic layer deposition To reference this document use: http://resolver.tudelft.nl/uuid:004278b1-45f3-4ea2-beb9-8582969981b5 DOI https://doi.org/10.1116/6.0000652 TNO identifier 946587 Publisher AVS Science and Technology Society ISSN 0734-2101 Source Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, 39 (39) Document type article Files To receive the publication files, please send an e-mail request to TNO Library.