Area-Selective Deposition of Tantalum Nitride with Polymerizable Monolayers: From Liquid to Vapor Phase Inhibitors

Abstract

Area-selective depositions (ASDs) exploit surface reactivity differences to deposit a material on a desired growth surface. This chemically driven process produces a reflection of the prepattern, commonly, through the use of either atomic layer deposition (ALD) or chemical vapor deposition (CVD). The ASD of TaN may offer significant benefits in device fabrication. For instance, in silicon technologies, this offers the ability to lower the resistivity between metal interconnect levels and therefore to reduce stage delay (RC delay). However, the deposition of TaN thin films in an area-selective manner is challenging due to the temperature requirements for a high-quality ALD film, which may exceed the thermal stability of typical organic surface modifications. We report on the synthesis of an organic inhibitor that incorporates a thermal/photoreactive diyne moiety to enable cross-linking of the inhibitor film and subsequent use in a selective TaN process, which was maintained over a large process window, during the 300 °C TaN ALD process. On patterned substrates, up to 3.8 nm of a TaN film could be deposited on SiN or mesoporous SiCOH without detectable Ta amounts on either a Cu or W surface. The same concept of cross-linking the inhibiting layer was also applied to a reactive vapor-phase inhibitor, propargylamine, found to inhibit TaN, though with a narrower process window (on blanket films). On via patterns, this selective TaN process was achieved but exhibits a distinct tapered profile. The methods described demonstrate the compatibility of several reactive inhibitors to enable the selective deposition of TaN at an ALD temperature compatible with many device fabrication schemes.

Self-Aligned Nanopatterning and Controlled Lateral Growth by Dual-Material Orthogonal Area-Selective Deposition of Poly(3,4-ethylenedioxythiophene) and Tungsten

“…A similar growth of PEDOT was observed on coplanar patterns with a smaller pitch size [substrate (iii)], but the tapered growth across the SiO 2 region was more pronounced, as shown in Figure S11. We hypothesize that the feature- and shape-dependent growth of PEDOT films originates from spatially dependent reactant consumption by surface diffusion and gas-phase transport during PEDOT oCVD. ,, …”

“…We hypothesize that the feature-and shape-dependent growth of PEDOT films originates from spatially dependent reactant consumption by surface diffusion and gas-phase transport during PEDOT oCVD. 7,40,41 The thickness of the W and PEDOT films produced on the patterned wafers in Figure 6c,g can be directly compared to the thickness measured on blanket substrates prepared under the same conditions (i.e., N = 10 s of PEDOT oCVD at 125 °C and N = 10 cycles of W ALD at 220 °C). The thickness obtained on each substrate is summarized in Table S1.…”

Self‐Formation of a Ru/ZnO Multifunctional Bilayer for the Next‐Generation Interconnect Technology via Area‐Selective Atomic Layer Deposition

“…[ 16 ] The successful growth of transition metal nitrides using AS‐ALD has been reported. [ 17–19 ] Lionti et al. reported the AS‐ALD of TaN using (3‐(12‐(tricosa‐11,13‐diynoyloxy)dodecanamido)propyl)phosphonic acid as an inhibitor.…”

“…The polymerized SAMs exhibited high thermal stability, and a TaN film of up to 3.8 nm was deposited on SiN or SiCOH without TaN deposition on Cu or W during the TaN ALD process. [ 19 ] However, TaN requires a high deposition temperature above ≈300 °C, and common inhibitors, such as alkanethiols, are decomposed at these temperatures. [ 20 ] Therefore, TaN might not be suitable for AS‐ALD using inhibitors.…”

“…[16] The successful growth of transition metal nitrides using AS-ALD has been reported. [17][18][19] Lionti et al reported the AS-ALD of TaN using (3-(12-(tricosa-11,13-diynoyloxy)dodecanamido)propyl)phosphonic acid as an inhibitor. [19] The inhibitor was selectively adsorbed onto W to form SAMs, which were polymerized using UV exposure or heat treatment because of the diyne moiety of the inhibitor.…”