Invited Paper PS1-WeA8
Plasma-Wall Interactions in Inductively Coupled Plasma Reactor and a Novel Method for Wall Condition Control
Wednesday, October 17, 2007, 4:00 pm, Room 606
Semiconductor technology has been aggressively scaled from micron sized features to 45 nm features over the last three decades . For the upcoming 32 nm technology node, total variation from all sources for a typical gate etch process is expected to be less than 2 nm. In addition, many new materials are being introduced in recent etch stacks, adding to the productivity challenges due to increased likelihood on non-volatile etch by-products on chamber walls. Plasma-wall interactions have significant impact on the chemistry of low pressure (<100 mTorr) plasmas. Therefore, control of chamber wall condition is crucial for achieving the desired process capability. Waferless Auto Cleans (WAC) have been demonstrated as essential in controlling wafer to wafer process repeatability in volume manufacturing above 65nm node. WAC removes etch by-products deposited during the wafer etch, minimizing drifts in chamber condition. However, ensuring no buildup of etch by-products on reactor walls is not sufficient to meet the productivity requirements of sub-65 nm node in many cases. Advanced Chamber Condition Control technology (AC3TM) is a novel method to significantly enhance the productivity of etch systems in volume production. AC3 involves deposition of a thin film on the reactor walls prior to wafer processing, thereby eliminating drift in the wall condition during production. Impact of changes in the wall conditions due to chamber wet cleans, parts aging and variability are significantly reduced, allowing CD control at the nanometer level.