Interfacial Chemistry of Metal Films on Polymers: Diffusion, Oxidation, Trace Components Studied by XPS, ISS, and SIMS
The advantages of flexible circuit boards (PC) made from sputtered metals on polymer substrates are becoming very obvious and demand for such products is dramatically increasing. In order to optimize the production and performance of such films it is essential to understand the chemical processes involved. The chemistry of these thin films, which consist of tens to hundreds of Angstroms of metals on various polymers, exhibits large variations from the outer surface to the interface. This chemistry is largely affected by the nature of processing and treatment and generally includes three distinct areas of interest: The outer surface; the central or bulk material, and the interfacial area. This chemistry is amenable to analysis by only a few modern analytical tools including XPS, ISS, and SIMS. The requirements for ion sputtering metals onto polymers and the equipment used are discussed below along with detailed analytical information obtained about the interfacial diffusion, oxidation, and trace components monitored throughout some of the resulting films.
KeywordsDepth Profile Metal Film Concentration Depth Profile Scan Auger Microprobe Flexible Print Circuit Board
Unable to display preview. Download preview PDF.
- 1.DOD, ANSI/IPC-FC-241C. “Flexible Metal-clad Dielectrics for Use in Fabrication of Flexible Printed Wiring”.Google Scholar
- 2.E. Klokholm, Delamination and fracture of thin films, IBM J. Res. Dev. 31, 5 (September 1987).Google Scholar
- 3.S. Schiller, G. Beister, and W. Sieber, Reactive D.C. high-rate sputtering — Deposition rate, stoichiometry and features of TiO2 and TiN films with respect to the target anode. Paper presented at the International Conference on Metallurgical Coatings, San Diego, CA, April 1983.Google Scholar
- 4.S. Schiller, U. Heisig, C. Kordorfer, G. Beister, J. Peschke, K. Steinfelder, and J. Strumpfel, Reactive DC high-rate sputtering as production technology. Paper presented at the International Conference on Metallurgical Coatings, San Diego, CA, March 1987.Google Scholar
- 5.L. Homstad, “X-ray Diffraction Measurements of Single Layer Flexible Media”. Unpublished internal report, Magnetic Peripherals, Inc., November 1984.Google Scholar
- 7.G. R. Sparrow, The role of surface chemistry in electronic packaging failure analysis, paper presented at the Twelfth Annual International Symposium for Testing and Failure Analysis, Los Angeles, CA, October 1986.Google Scholar
- 8.D. Briggs, “Handbook of X-ray and Ultraviolet Photoelectron Spectroscopy”, Heyden, London,1978.Google Scholar
- 9.D. Briggs and M. P. Seah, editors, “Practical Surface Analysis by Auger and X-ray Photoelectron Spectroscopy”. John Wiley and Sons, London 1983.Google Scholar
- 10.G. R. Sparrow and E. Mishmash, Surface analysis of polymers and glass by combined ISS/SIMS, paper presented at the 1977 Pittsburgh Conference on Analytical and Applied Chemistry, Cleveland, OH, March 1977.Google Scholar
- 11.W. J. van Ooij, Investigation of metal-polymer interfaces, paper presented at NSF Workshop on Adhesion Science and Technology, Stanford Science Camp, Lake Tahoe, CA, October 14–16, 1987.Google Scholar
- 13.W. J. van Ooij, R. H. G. Brinkhuis, and J.M. Park, Adhesion of copper and chromium films to polyimide studied by static SIMS of the interface, Private Communication, 1988.Google Scholar