ANISOTROPIC REACTIVE ION ETCHING OF ALUMINUM USING CL2, BCL3, AND CH4 GASES

A technique for anisotropically etching fine line patterns in aluminum films using the gas combination Cl2:BCl3:CH4 is explored. The process is designed to avoid the use of CC14 and CHC13, both of which are known to be strong carcinogens. The etch is characterized by making use of statistically designed experiments to optimize the etch rate, selectivity, and anisotropy of the etch. The etching mechanism is explored by the use of Auger electron spectroscopy to study polymer side-wall deposits, caused by the use of CH4 and an organic mask, which prohibit undercutting. Using this etch, we have demonstrated the anisotropic etching of fine line features in A1 films with minimum lines and spaces of 500 and 300 nm, respectively. © 1990, The Electrochemical Society, Inc. All rights reserved.