Angus McCarter, Thomas Gilmore, Anshu Verma, Impedans Ltd., Dublin, Ireland
Radio frequency (RF) and DC/Pulsed DC plasma sources have emerged as essential instruments in thin film deposition and precision coating. Attempts to further control the films properties have resulted in new technologies, such as High Power Impulse Magnetron Sputtering (HiPIMS) and Tailored Waveform biasing. A detailed comprehension of the underlying mechanisms within the plasmas, and the plasma-surface interactions, is needed now more than ever to meet the needs of commercial applications, such as precision optical coatings. Issues pertaining to the plasma and the source can result in compromised film quality, diminished productivity, and increased downtime of sputtering equipment.
Impedans plasma sensors, offer customized solutions to any kind of challenges encountered in sputtering tools, encompassing concerns related to plasma uniformity and ion bombardment. The RF-compensated, self-cleaning Langmuir probes by Impedans give precise measurements of electron density, temperature, and plasma potentials, enabling the generation of spatial and temporal profiles within the plasma to ensure uniformity across large surface areas. Impedans also has the novel Plato Langmuir probe for high deposition rate coating tools, giving visibility to the plasma parameters for the first time. The Quantum ion energy analyzer directly measures the ion energy and flux impacting the substrate, with an embedded quartz crystal microbalance (QCM) to measure deposition rates. This QCM is below the energy discriminators, allowing direct measurement of the ion/neutral ratio. This data enables precise control over the structural attributes of the deposited thin films and allows process transfer by matching ion/neutral ratios tool to tool. Finally, the Octiv VI probes serve to monitor their impact on the current, voltage, and impedance of the plasma for RF and Pulsed DC sources, thus ensuring process repeatability. This talk will present the applications of these sensors across diverse sputtering systems for process development and improvement.