Dry Etching (Part 2): Influence of Chemical Contamination and Defects on Dry Etching

Abstract

In this chapter, problems related to chemical contamination, defects and radiation damage are dealt with, and their influence on the etching characteristics and the reaction mechanism are discussed. Methods to improve the efficiency of dry etching can be classified as “physical methods” and “chemical methods”. Physical methods are, for example, reduction of the pressure to improve the ion incidence direction and to control the width of the micro-pattern better, and selectively lowering the energy of the injected ion incidence. For this purpose, low-pressure high-density plasmas, such as ECR, magnetron, helicon waves or inductive coupled plasma, are studied. With the further miniaturization and integration of devices, these high-density plasma systems cause problems due to charging damage of the ever-thinner gate oxide film [1]. The charging due to a lack of uniformity in the plasma was solved by improving the distribution of the plasma by optimizing the shape of the magnetic field and changing the substrate bias to low frequency.