AVS 49th International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeA

Paper VT-WeA7
Closed Loop Process Control for Reactive Sputter Deposition of Dielectric Films

Wednesday, November 6, 2002, 4:00 pm, Room C-104

Session: Vacuum Measurements, Components, and Control
Presenter: D. Carter, Advanced Energy Industries
Authors: D. Carter, Advanced Energy Industries
H. Walde, Advanced Energy Industries
G. McDonough, Advanced Energy Industries
G.A. Roche, Advanced Energy Industries
Correspondent: Click to Email
Pulsed-dc reactive sputter deposition of dielectric films has be an active area of study over recent years. It has been demonstrated that transition region sputtering can produce quality dielectric films at high deposition rates making this approach attractive to the alternatives of high frequency sputtering from ceramic targets. As with all processes, time based control and repeatability are critical to the acceptance of such technology. While voltage reversal during pulsing has proven effective in stabilizing arc activity, additional controls are required to stabilize the reactive environment to ensure film composition and controlled sputtering target condition. Various techniques are available to monitor the sputtering environment including partial pressure, optical emission and sputter source impedance but all typically require the addition of costly, complex, intrusive and sometimes unreliable components if one is to be used in a feedback-control-loop system. This study looks at a non-intrusive, cost effective approach to the incorporation of a Closed-Loop-Control (CLC) system in a pulsed-dc reactive sputter deposition process for the production of Al2O3 and SiO2 thin films. This approach uses target voltage as the primary feedback parameter to directly control the setpoint to a high-speed sonic piezo-driven mass flow controller. Target transition region control is demonstrated in the aluminum-oxygen and silicon-oxygen systems and the approach is evaluated for film quality, long-term process stability, process repeatability, and susceptibility to arcs and other potential anomalies encountered in such difficult to control reactive processes.