A maskless etching technique which is useful for solar cell manufacturing and microelectronics was examined using the localized surface discharge plasma at atmospheric pressure. Etchings were carried out on a crystalline silicon (Si) substrate and a silicon nitride (SiN) film coated on a Si substrate. Two- and three-dimensional etching profiles were investigated. Based on the results, etching rates and an etching mechanism were discussed. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.