Influence of driving method on discharge mode of damage free remote plasma removal process for semiconductor manufacturing

Summary form only given. Applied Materials' funnel-shaped electrode configuration for remote plasma process is being used for oxide removals in semiconductor manufacturing process. Remote plasma removal process actively uses chemically activated species from plasma rather than charged particles that could possibly damage the structures fabricated on the wafer.Electrical and optical characteristics by using probe technique and optical emission spectroscopy (actinometry) has been investigated to optimize the funnel-shaped electrode structure which is hollow cathode concept design. Plasma generations inside the electrode has been studied with various type of driving methods of pulsed DC, low frequency (<;1MHz) and radio frequency (>1MHz). Spatiotemporal plasma diagnostics by using ICCD (intensified chargecoupled device) camera confirms that low frequency driving enables dual discharge modes operation - glow and hollow cathode discharges while pulsed-DC driving gives only single mode operation. Also, time-resolved images by ICCD camera reveal that radio frequency driving has different discharge mode with different electron heating mechanism than low frequency driving. The oxide etch rates and 300mm in-wafer uniformities have been compared with various driving methods. To maximize the hollow cathode effect in the funnel-shaped electrode configuration, the pulsed-DC has been investigated. Pulsed-DC operation with funnel-shaped electrode configuration enables strong hollow cathode effect at the center of the electrode improving electron impact ionization as well as radical generation. Wafer process performances of pulsed-DC driving, such as etch rate, uniformity and cleanness has been compared to the process performance of other driving techniques.