| AVS 61st International Symposium & Exhibition | |
| Selective Deposition as an Enabler of Self-Alignment Focus Topic | Wednesday Sessions |
| Session SD-WeM |
| Session: | Fundamentals of Selective Deposition |
| Presenter: | Yves Chabal, University of Texas at Dallas |
| Authors: | L. Liu, University of Texas at Dallas W.J.I. DeBenedetti, University of Texas at Dallas S. Karakaya, University of Texas at Dallas T. Peixoto, University of Texas at Dallas R. Hourani, Intel Corporation D.J. Michalak, Intel Corporation Y.J. Chabal, University of Texas at Dallas |
| Correspondent: | Click to Email |
There is an increasing need to develop selective functionalization of surfaces. This goal requires careful control over surface cleaning, intermediate passivation, and chemistry (either vapor phase or wet) on oxide, semiconductor, and/or metal surfaces, many of which have not have been well-studied in the past. It is therefore critical to bring to bear a number of characterization techniques that can provide sufficient information to fully understand each of these three steps (cleaning, passivation, functionalization).
This talk will illustrate the role of characterization in examining surfaces such as silicon nitride, silicon oxide, and metallic surfaces with a unique cluster tool equipped with in-situ infrared (IR), X-ray photoelectron spectroscopy (XPS) and low-energy ion scattering (LEIS) for bonding, elemental, chemical and spatial characterization. These techniques are coupled with ex-situ AFM, spectroscopic ellipsometry, and SEM for full characterization of interesting surface species and products. Following a goal to achieving chemical selectivity between Si3N4 and SiO2 surfaces, we first focus on the surface chemistry after cleaning and etching with aqueous HF. While H or NHx is typically believed to be the chemical termination of HF-etched silicon nitride surfaces, we find that such surfaces not only require careful preparation to remove salt byproducts, but are also essentially fluorine terminated. Despite the clear difference in surface termination between nitrides and oxides, both surfaces display surprisingly similar reactivity and bonding upon exposure to chloro- and ethoxysilane molecules: both surfaces display the formation of Si-O-Si bonds but the nitride surfaces show little removal of fluorine. We propose a novel concept for surface reaction involving the activation of surface atoms back-bonds, such as Si-N/Si-O in the case of F-terminated Si3N4. While such a process does not lead to selective chemistry of silicon oxide and nitride surfaces, its understanding opens the way for the selection of appropriate molecules for selectivity.