The evolution of Pd/Sn catalytic surfaces in electroless copper deposition
journal contributionposted on 15.10.2013, 07:51 by Xiaoyun Cui, David HuttDavid Hutt, David J. Scurr, Paul ConwayPaul Conway
This paper describes the different catalytic surfaces of Pd/Sn formed before electroless copper deposition onto a glass substrate. In this study, silanization of the glass surfaces with (3-aminopropyl) trimethoxysilane was used to provide a surface-coupled layer of functional molecules to assist in the adsorption of Pd/Sn catalyst and the subsequent copper deposition. The composition and microstructure of the modified glass surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry. These showed that catalytic Pd/Sn structures on the surface changed with increasing immersion time in the catalyst bath. The core-level XPS spectrum of Pd indicated that metallic Pd(0) became more significant in the catalyst layer than Pd(II) with the increasing immersion time. A model of the adsorption process is proposed to explain these changes. It was observed that too high a quantity of Pd(0) does not always improve the adhesion of the Cu deposits in the electroless process.
The authors acknowledge the EPSRC for financial support through the Innovative Electronics Manufacturing Research Centre. The technical support of Qioptiq is also gratefully acknowledged. Loughborough University assisted in meeting the publication costs of this article.
- Mechanical, Electrical and Manufacturing Engineering