TABLE OF CONTENTS Atoms of a solid surface are removed under irradiation by energetic ions. This phenomenon is called "sputter etching." The sputter etching process is governed by collisions between the irradiated atoms and the surface atoms of the solid target. The interaction depth for sputter etching is around 100 beneath the surface. When the surface of a solid is bombarded by argon ions, the adsorbed gases are removed and a clean surface is produced. The thinning of specimens is achieved by argon ion bombardment for fabricating test pieces for electron microscope analysis. The sputter etching process is a key technology for the fabrication of Si ICs.
In this chapter, the sputter etching process for microfabrication is described in relation to the fabrication of thin-film electronic devices.
A physical process governs the mechanism of sputter etching by the bombardment of energetic inert ions. Bombardments by chemically reactive ions deliver surface etching through chemical reactions. Since the sputter etching is processed in a vacuum using gas-discharge plasma, the etching process is called "dry etching." Dry etching is a key technology for making masking patterns for large scale integration (LSI) and detailed descriptions can be found in the literature.[1][2]
Figure 7.1 shows a classification of dry etching systems and Fig. 7.2 shows their basic construction.[3] Dry etching is classified into three types of etching processes according to the energy of incident species, i.e., ions and/or excited atoms.
