| AVS 66th International Symposium & Exhibition | |
| Atomic Scale Processing Focus Topic | Monday Sessions |
| Session AP+2D+EM+PS+TF-MoM |
| Session: | Area Selective Deposition and Selective-Area Patterning |
| Presenter: | Adrie Mackus, Eindhoven University of Technology, The Netherlands, Nederland |
| Authors: | M.J.M. Merkx, Eindhoven University of Technology, The Netherlands D.M. Hausmann, Lam Research Corporation W.M.M. Kessels, Eindhoven University of Technology, The Netherlands T.E. Sandoval, Universidad Técnica Federico Santa María, Chile A.J.M. Mackus, Eindhoven University of Technology, The Netherlands, Nederland |
| Correspondent: | Click to Email |
The development of new processes for area-selective atomic layer deposition (ALD) is currently motivated by the need for self-aligned fabrication schemes in semiconductor processing. For example, area-selective ALD processes for dielectric-on-dielectric deposition are being considered for fully self-aligned via (FSAV) fabrication schemes in advanced interconnect technology.
Instead of solely relying on surface functionalization prior to ALD, an novel strategy to area-selective ALD involves the dosing of inhibitor molecules during every cycle in an ABC-type recipe.1,2 By using small molecules that can be dosed in vapor-phase as inhibitor, this approach is compatible with industrial process flows. Moreover, the reapplication of the inhibitor molecules during every cycle allows for the use of a plasma as the co-reactant, which broadens the range of materials that can be deposited selectively. In contrast to conventional approaches to area-selective ALD based on self-assembled monolayers (SAMs), very little is known about how small inhibitor molecules can block the ALD growth.
In this contribution, insight into the mechanisms of precursor blocking by inhibitor molecules as obtained from in-situ Fourier transform infrared spectroscopy (FTIR) and density functional theory (DFT) calculations will be discussed. Area-selective ALD of SiO2 using acetylacetone (Hacac) as inhibitor will be described as a model system, illustrating various mechanisms that can contribute to the loss of selectivity. It was found that at saturation, Hacac adsorbs through a mixture of chelate and monodentate bonding configurations. Hacac in monodentate configuration is displaced from the surface when exposed to bis(diethylamino)silane precursor molecules, which limits the selectivity. Strategies for improving the selectivity based on the understanding from these studies will be discussed.
1 A. Mameli, M.J.M. Merkx, B. Karasulu, F. Roozeboom, W.M.M. Kessels, and A.J.M. Mackus, ACS Nano 11, 9303 (2017).
2 A.J.M. Mackus, M.J.M. Merkx, and W.M.M. Kessels, Chem. Mater. 31, 2 (2019).