Processing - Reactive ion etching

Reactive ion etching (RIE) is a plasma-based process developed to physically imprint semiconductor circuit features into the surface of a wafer. The ionization of a controlled mixture of gases localized above a sample serves to remove any exposed portion of the sample's surface area via a combination of chemical reaction and physical bombardment.

In addition, the electrical properties of the plasma can be exploited in order to produce extremely anisotropic etch characteristics. This offers certain advantages over more conventional wet chemical bath etching, which tends to etch isotropically or favour certain crystallographic directions. Thus, RIE can be well suited to the fabrication of features with extremely deep, vertical side walls, and highly consistent critical dimensions.

The quality of features etched by RIE depends on a number of process parameters, including:

  • gas flow rates
  • chamber pressure
  • RF power
  • chamber temperature
  • pattern density

The CEDT owns and operates a Surface Technology Systems reactive ion etching system, model 320PC, located in TAB 110. The system is dedicated to silicon-based materials applications.

For etching III-V materials, an electron-cyclotron-resonance-RIE system (ECR-RIE) is located in the clean room, JHE A306.