465768 Topographically Selective Deposition of Dielectrics Using Ion Implantation

Sunday, November 13, 2016: 4:18 PM
Golden Gate 5 (Hilton San Francisco Union Square)
Dara Bobb-Semple1, Fatemeh Hashemi2, Yin Fan3, Tobin Kaufman-Osborn3 and Stacey F. Bent1, (1)Chemical Engineering, Stanford University, Stanford, CA, (2)Material Science and Engineering, Stanford University, Stanford, CA, (3)Applied Materials, Sunnyvale, CA

High quality thin films are important for diffusion barriers, adhesive buffer layers, etch stops and sacrificial layers in integrated circuits, MEMS and NEMS. Achieving maximum performance requires great precision in the fabrication technique. Advancements in technology and miniaturization of these devices require uniform, conformal coatings of complex, high aspect ratio features (steps, trenches, grooves and pores) on the nanoscale. Today’s device fabrication is based on ‘top-down’ processes with multiple photolithography and etch steps which serve as the main bottleneck for device downscaling. Area-selective atomic layer deposition (AS-ALD) which combines surface modification and ALD in a ‘bottom-up’ approach to nanopatterning provides a promising alternative.

Previous studies have found that selectivity in AS-ALD relies on a change in hydrophobicity whereby more hydrophobic surfaces were found to cause an extended nucleation delay. Most reports on AS-ALD typically exploit this property, using tightly packed self-assembled monolayers (SAMs), which increase hydrophobicity, to modify the substrate surface. There are several challenges associated with the use of SAMs including degradation under ALD conditions, lengthy deposition times, and a limited number of suitable chemistries. To overcome these challenges, there is a need for new methods of surface modification to make AS-ALD a more viable technique.

In this presentation, a novel approach in AS-ALD will be described, whereby the substrate surface (Si) is modified through fluorocarbon implantation. It has been shown that through this process, a thin (~1.5 nm) fluorocarbon layer forms on the Si surface, making it hydrophobic (WCA ~104°). In a previous study by this group, this method was found to be successful in blocking Pt ALD up to 500 cycles. In this work, the implanted substrate’s ability to block ALD of dielectrics (Al2O3, ZnO, HfO2) is evaluated. Substrates with two and three dimensional features are also investigated. Nucleation on the implanted substrate (or regions) is investigated and compared to a non-implanted reference surface. Several techniques including, atomic force microscopy, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy and Auger electron spectroscopy are used for analyses and characterization. The results show that there is reduced oxide growth on the more hydrophobic, implanted substrate.  The potential and limitations of the ion implantation approach to AS-ALD will be discussed.


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See more of this Session: Plasma and Electrochemical Deposition Techniques
See more of this Group/Topical: Materials Engineering and Sciences Division