A new process has been developed to produce patterned copper films with small feature sizes on polytetrafluoroethylene (PTFE). In the first step a sodium naphthalenide etching solution was used to chemically modify PTFE and also create a rough surface which provided good adhesion characteristics. In the second step a KrF excimer laser irradiated the substrate through a mask, ablating the etched layer and leaving a pattern. The typical total absorbed laser energy required to ablate the etched layer was 575 mJ cm(-2) and X-ray photoelectron spectroscopy (XPS) analysis showed that the ablated region had a composition similar to that of unmodified PTFE. In the third step, high purity copper was deposited selectively on the unablated regions in a cold wall reactor using (hfac)Cu(VTMS) (hfac = hexafluoroacetylacetonate; VTMS = vinyltrimethylsilane) at deposition rates up to 1 mu m min(-1) at 180 degrees C and 10 mTorr partial pressure of (hfac)Cu(VTMS) to give films 15-20 mu m thick of high purity copper on PTFE. Film resistivities were near bulk values. There are several advantages to this procedure compared with conventional approaches : (1) wet etching and liquid wastes are avoided; (2) conducting paths with dimensions less than 20 mu m can be produced; (3) excellent adhesion is obtained; (4) owing to the high energy density available from an excimer laser, rapid throughput is possible.