Effects of plasma on excimer lamp based selective activation processes for electroless plating

Several photoselective activation processes for electroless plating have been reported in recent years using excimer lamps to selectively photodecompose chemical coatings. In this work, optical emission spectroscopy OES.of a plasma existing in a process chamber during operation of a 222 nm KrCl) excimer lamp is presented. This plasma is shown to be generated by the excimer lamp power supply rather than by the UV excimer lamp radiation and is pressure dependent in the range from 4.0=10y4 mbar to atmospheric pressure. The effects of this plasma on previously reported pressure dependence of these photo-selective activation processes for electroless plating are discussed. The plasma assisted nature of the selective decomposition process for electroless plating is demonstrated. The conditions required for a true photolytic process under excimer lamp radiation are reported. q1999 Elsevier Science B.V. All rights reserved.