Polymer assisted area selective ALD of multilayered materials using alkylamine precursors

Area selective atomic layer deposition (AS-ALD) has gained considerable attention in nanomanufacturing due to its potential for precise material placement. While most research to date has focused on the selective deposition of layers of a single material, extending AS-ALD to multi-material and multilayer systems presents additional challenges. These include ensuring the compatibility of ALD processes in terms of temperature windows and chemical selectivity. In this study, we introduce AS-ALD of SnOx and TaOx using polymethylmethacrylate (PMMA) as a masking layer. The ALD of SnOx and TaOx was performed using dialkylamine precursors and water at a deposition temperature of 120°C on blanket Si and PMMA substrates. Both processes achieved selective deposition on Si with native oxide, with negligible growth on PMMA after 150 ALD cycles. AS-ALD was further demonstrated on patterned substrates consisting of alternating PMMA and SiOx lines, followed by PMMA removal via O2 plasma treatment. Finally, the optimized individual SnOx and TaOx processes were applied sequentially to selectively deposit a bilayer on the SiOx regions, with no growth on the PMMA patterns. This demonstrates that selective multilayer deposition is achievable using a single sacrificial template without intermediate processing steps. This combinatorial approach using metal alkylamine precursors and PMMA masking offers a promising pathway for fabricating patterned multilayer structures in device manufacturing using AS-ALD.