Rapid modification of thin films by a large-area electron beam

Abstract

Rapid modification of thin films on a semiconductor silicon wafer was carried out using a large-area cold cathode discharge electron beam. Three processes were undertaken using this novel electron beam. Firstly, in the rapid processing of a boron-ion-implanted silicon wafer, sheet resistance, X-ray diffraction, Raman spectroscopy and secondary ion mass spectrometry analyses indicated that this technique has the advantage of rapid processing with little diffusion of the dopants. Secondly, in the formation of TiN on an SiO 2/Si wafer by rapid nitridation modification with this electron beam, the results of Rutherford backscattering spectrometry and X-ray diffraction studies showed evidence for TiN in the specimen after several tens of seconds of exposure to the electron beam. Thirdly, in the dry anisotropic etching of molybdenum films, an etching rate of greater than 175 nm min −1 was obtained in a CF 4HeO 2 gas mixture. Scanning electron microscopy revealed a linewidth of 1.5 μm and showed the effect of anisotropic etching. Rapid modification by the electron beam may be concluded to be a predominant driving mechanism.