Substrate Secrets

There are two basic types of plasma treaters available for metallizers, the hollow cathode type as designed by Sigma Technologies, and the Dual Magnetron type designed by the metallizer suppliers. Dual magnetron plasma sources are produced from sputtering cathodes with a surface plate which will not actively sputter when used for a plasma source. This makes perfect sense for the metallizer companies as they just use their existing sputtering cathodes while the hollow cathode design was designed for film treatment in the metallizer.

The lingering question is does it matter to the film? It will matter to the process settings of gas flow and power level and which gas blend is best for etching the film surface. Also it will matter to a certain extent as to how easy it is to retrofit into the existing metallizer. My first purchase of a plasma treater needed the engineering to fit it into the machine and this engineering process is as important a process as the selection of the plasma technology to the overall success of the installation.

Today I expect that metallizers are sold with the space for the plasma treater pre-engineered in the equipment design even if the treater is not purchased with the new machine. If not you will have to do the engineering to find a place in the web path to add the treater. Plasma treaters are located in the unwinding chamber of the two chamber designs as the pressure level must be high enough for the plasma to start, and the winding chamber pressures are just about optimum where the high vacuum deposition zone would be too low a pressure.

To choose a plasma treater, I would recommend that you test with your film samples with the types of plasma generators, hollow cathode and dual magnetron, and explore the impact of gas types, gas blends and power level on the performance of your particular substrate. In my mind, such an experimental study is absolutely necessary to guarantee you chose the right technology for your application.