Low temperature oxidation and selective etching of chemical vapor deposition a-SiC:H films

Abstract

Chemical vapor deposition silicon carbide films are considered as a perspective hard mask and stop layer in advanced dry etch technology because of the high chemical and plasma stability. However the a-SiC:H film should be etched away after technological use. In this case the high chemical stability of the a-SiC:H films troubles the solution of this problem. A new approach for the selective removal of the a-SiC:H films is discussed. The basic idea is low-temperature oxidation of the a-SiC:H film and selective removal of the reaction products by wet and/or dry etching. Fourier transform infrared, x-ray photoelectron spectroscopy, and ellipsometry were used for the characterization of the a-SiC:H oxidation and etching of the reaction product. As an example of the practical application, the a-SiC:H films were tested as a dry contact etch stop layer in a 0.18 μm complimentary metal–oxide–semiconductor technology. Results of the electrical evaluation of test structures prepared by this technology are discussed. These results show significant advantage of the new technology compared with the traditional one.