I n situ vacuum processing technology is becoming increasingly important with the increasing scale of integration and continuing shrinkage of device dimensions. Ion beams induce various chemical effects which are very promising for applications such as in situ processing technology, with the promise of improved high processing rates and low process-induced damage. The present paper is intended to review various etching and deposition techniques which utilize ion beam induced chemical effects. The effect of damage and importance of a low energy beam will also be described.