Study of Aminosilane-Compound Modification Condition on Polished Silicon Wafer and Its Influence on the Adhesion of Electroless Nickel/Phosphorous Film

Electroless deposition (ELD) of nickel/phosphorous (Ni/P) layer has been a special interest in modern technique, especially in the production of diffusion barriers in the silicon industry [1]. The crucial part of ELD is a catalytic reaction that needs a trace amount of palladium [2] as the activator to lower the activation energy of metal formation. Due to the adhesion of ELD Ni/P film is associated with the interfacial property of catalyst and silicon surface. In order to increase the bridging between the silicon substrate and palladium catalyst, modifying silicon surface with organo-silane compound such as 3-[2-(2-aminoethylamino)ethylamino] propyl-trimethoxysilane (ETAS). The ETAS then form a self-assembled monolayer (SAM) to facilitate the adsorption of palladium catalyst [3]. However, it is known that the SAM formation is very sensitive to process condition such as soaking time, soaking temperature and solvent agents. In this study, the ETAS modification condition on silicon wafer is investigated. In particular, the ETAS-modified film was fabricated by a wet-soaking method and the effects of soaking time, soaking temperature and solvent agents onto silicon surface were discussed. As shown in Fig 1, the images of AFM with various soaking time of ETAS-modified silicon surface showed significant difference; this means that the long soaking time did influence SAM formation. Finally, the adhesion of ELD Ni/P on ETAS-modified silicon surface with different process parameters is discussed.

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[3] T. C. Wei, T. P. Pan, C. M. Chen, K. C. Lai, C. H. Wu, Electrochem. Commun. 54 (2015) 6