Abstract
The mechanism responsible for the very high plating rates at electrodes illuminated by a laser beam was investigated. Absorption of the laser energy by the electrode results in a localized increase in temperature at the metal-solution interface. This leads to: (i) a shift in the rest potential, (ii) an increase in the charge transfer rate, and (iii) strong microstirring of the solution due to thermal gradients and, at high laser power densities, to strong local boiling. Verification of the first two effects was achieved by measuring the enhancement in plating rates as a function of overpotential, laser power, and substrate thickness and by comparing these results with measurements using solutions at various bulk temperatures. Observation of the cathode through a video monitor, as well as detection of bubble formation using a miniature microphone, verified that a correlation exists between the ejection of bubbles from the cathode and sharp increases in the current. Application of laser-enhanced electroplating for maskless generation of patterns is also briefly discussed. © 1981, The Electrochemical Society, Inc. All rights reserved.