Paper VT-MoM9
Modern Day Challenges to Ionization Gauge Lifetimes

Monday, October 19, 2015, 11:00 am, Room 230B

Ionization gauges were introduced into the vacuum market over half a century ago with the initial intent of extending pressure measurement ranges into the ultrahigh vacuum range. In more recent years, ionization gauges have been pushed into industrial applications with total pressures as high as 100 mTorr while operating in the presence of both reactive and corrosive gases. The harsh chemical and physical environments of industrial process chambers present very serious challenges to the lifetime of modern ionization gauges. Lifetime is defined as the time until the pressure gauge fails to either operate or produce measurements within its specified accuracy. Following the recent development of a new commercial cold cathode ionization gauge specifically designed to provide extended lifetime, our laboratory has been involved in root-cause analysis studies to understand gauge failures caused by the harshest process conditions. Our long term goal is to create a comprehensive knowledge-base of physicochemical interactions between processes and ionization gauges, provide best known vacuum measurement practices to the industry and develop longer lasting products that meet the demands of the modern vacuum market. In this presentation, we discuss a case study for a cold cathode gauge used in an ion implantation process that revealed some interesting and unexpected results. Most cold cathode gauge failure mechanisms reported in the vacuum technology literature have focused on sensitivity losses due to internal sputtering; however, we will illustrate an example in which a different phenomenon eventually led to gauge failure. It is evident to our group that discovery is far from over and that gauge lifetime challenges are continuously evolving.