Thermal desorption spectroscopic analysis for residual chlorine on Al–Si–Cu after Cl2 electron cyclotron resonance plasma etching

Abstract

Thermal desorption spectroscopy is used to measure the amount of residual chlorine on Al–Si–Cu. The Al–Si–Cu surface is etched by Cl2 electron cyclotron resonance (ECR) plasma at substrate temperatures of 30 and −60 °C. The surfaces are then cleaned by one of the following methods: de-ionized water rinsing, H2 ECR plasma irradiation, or annealing in H2/N2 mixed gas. AlCl molecules, which may be responsible for aftercorrosion, are detected. Chlorine compounds, however, cannot be detected by conventional x-ray photoelectron spectroscopy or Auger electron spectroscopy. The low substrate temperature etching reduces the amount of residual chlorine. Moreover, the cleaning ability of the H2 ECR plasma treatment is no less than that of the de-ionized water rinse, and is superior to that of annealing in H2/N2 mixed gas.