Advanced Sputter Coating Processes for Glass: Application of Plasma Emission Control to Cylindrical Magnetrons

Phil Greene, Jim Rietzel, Steve Nadel, Johannes Strümpfel

Over the last decade, the cylindrical magnetron has emerged as the leading technology for sputter coatings on glass. The ability to deposit a wide range of technologically critical films such as TiO2, SiO2 and Si3N4 has enabled the continued evolution and growth of low-emissivity, display and other coating applications. However, the need to deposit more complex multi-layer films at higher deposition speeds with improved efficiency and cost continues to push the performance requirements.

The ability to deposit thin films onto glass at ever-increasing deposition speeds and greater precision relies on a complex interplay of technological components. Pumping speed and dynamics, magnetron design, applied power waveform, target fabrication, gas distribution and the process control algorithms linking these components are all critical determinants in pushing the limits of sputter technology and reducing coating costs. These technical requirements have been met with a closed loop control system based on Plasma Emission Monitoring, combined with fast response gas fl ow systems, high pumping speed confi gurations and mid-frequency AC sputter power supplies. This paper will review the state of the art in high rate deposition and show the critical components required for long term high rate deposition with high film uniformity.

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