Neutral Beam Cleaning/Etching with Superthermal Atomic Hydrogen

The objective of Phase I research to demonstrate the feasibility of neutral beam cleaning and etching of unprocessed/processed semiconductor wafers with intense superthermal atomic hydrogen beams. The superthermal hydrogen atoms are produced by electron impact dissociation of hydrogen gas in a dense plasma generated in a novel type of a microwave ECR discharge recently developed by the principal investigator. The atoms have a thermal distribution with a temperature of several eV and a flux density in the order of 1 A/cm2 equivalent. The energy of the neutral superthermal atomic hydrogen beam is similar to the hydrogen ion energy in a successful mirowave ECR plasma processing tool, and the beam intensity is higher than the ion current density of currently available plasma processing tools. The energy range of the atoms may be high enough for chemical reactions at low surface temperature, and at the same time low enough to prevent bombardment induced damage and hydrogen diffusion into the bulk. There is no charge induced damage since neutral particles are used. Since no chrorofluorocarbons are used, this method addresses current environmental concerns. In Phase I etchin of oxides, especially removal of the native oxide from silicon, will be demonstrated. Etching of carbon and silicon will be also investigated. In Phase II an atomic hydrogen beam system will be developed for cleaning of large wafers. Anticipated Benefits: Exploration of a new etching/cleaning technology based on utilization of superthermal hydrogen beams. This techniques will prevent damage due to particle bombardment and induced charge. Elimination of chrorofluorocarbons will address current environmental concerns. Development of atomic hydrogen system for wafer cleaning. Development of channeled anisotropic hydrogen beam etching system.