Design Considerations of a Differentially Pumped Cathode System for LAPPS
Abstract
The results of tests of a differential pumping system separating a plasma production cathode chamber and a processing chamber are presented. The tests are a series of measurements taken to evaluate two aspects of system performance. These are the effectiveness of the system to maintain large differential pressures, and, the degree to which different gases in the two chambers can be isolated from one another. It is found that the observed operating range of differential pressure is predicted by the measured conductance and pumping speeds fairly accurately, and the measured conductance themselves are scalable with channel width and pressure in a manner generally consistent with laminar flow. Through the RGA measurements, all three channels tested were found to isolate the cathode from the process chamber gas very well under all except the most egregiously lopsided input flow rates. As the channel is widened, more cathode source gas tends to mix with the process gas and the range of operating pressure becomes more limited. Both of these are alleviated as the pumping speed on the process chamber is increased.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 27, 2004
- Accession Number
- ADA420619
Entities
People
- Darrin Leonhardt
- David Blackwell
- Richard Fernsler
- Robert A. Meger
- Scott G. Walton
Organizations
- United States Naval Research Laboratory