Formation of copper patterns on poly(tetrafluoroethylene) via radiation controlled chemical etching and chemical-vapor deposition

Publisher Website
Google Scholar
Abstract
Patterned copper films have been deposited on poly(tetrafluoroethylene) (PTFE) in a three‐step additive process. In the first step, a pattern is produced by cross linking the PTFE surface in selected areas by irradiation with either electrons or x rays at dose levels below those that are either visually or spectroscopically apparent. The pattern is then developed by wet chemical etching in the second step in which only the nonirradiated areas are appreciably etched with sodium naphthalenide. In the final step, chemical‐vapor deposition using the precursor (hexafluoroacetylacetonato) Cu(I) trimethylphosphine at 200 °C results in Cu deposition only on the nonirradiated areas of the surface. The Cu films are continuous with a resistivity of 4 μΩ cm, high purity as determined by Auger electron spectroscopy and x‐ray photoelectron spectroscopy, and are sufficiently adherent to survive a Scotch tape test. Patterned feature sizes as small as 35 μm can be produced.