a second substrate in the presence of at least one plasma-forming gas. In this method, either the first and/or the second substrate contains a plurality of cavities so that when the first substrate is affixed to the second substrate the plurality of cavities are filled with the plasma-forming gas or gas mixture. In a preferred embodiment, a first substrate is advanced through a first roller assembly, which includes a roller with a plurality of nodules and a roller with a plurality of depressions. Both the plurality of nodules and the plurality of depressions are in registration with each other so that when the first substrate passes through the first roller assembly, the first substrate has a plurality of cavities formed therein. A second substrate is advanced through asecond roller assembly and then affixed to the first substrate in the presence of at least one gas so that when the two substrates are affixed the cavities are filled with the gas or gas mixture. In an alternate preferred embodiment, the second roller assembly includes a roller with a plurality of nodules and a roller with a plurality of depressions so that when the second substrate passes through the second roller assembly, the second substrate also has a plurality of cavities formed therein. In either of these embodiments, at least one electrode may be sandwiched between the first and second substrates prior to the substrates being affixed.

In another embodiment, at least one substrate is thermally treated in the presence of a least one plasma-forming gas so as