Angus McCarter, Thomas Gilmore, Anshu Verma, Impedans Ltd., Dublin, Ireland
In this talk we will present common challenges with plasmas in vacuum coating tools and showcase monitoring solutions. Plasma sources play a pivotal role in semiconductor manufacturing, necessitating a comprehensive understanding of plasma mechanisms and rigorous process repeatability checks for large-scale production. Key process parameters, such as gas pressure, RF/ bias power are critical for ensuring the high quality and performance of the semiconductor components. Challenges related to the plasma and the RF line can result in compromised wafer quality, diminished productivity, and increased downtime. Also, early detection of wafer faults is imperative to prevent defective wafers from progressing downstream, ensuring high yields.
Impedans plasma sensors offer customized solutions for manufacturing challenges including process monitoring, fault detection and arc monitoring etc. The Octiv VI probes are in-line RF voltage, current and phase measurement tools. They can measure from 40 kHz to 100 MHz (RF or Pulsed DC), with powers from 10s of Watts to 90 kW are available. The measured impedance correlates with the chamber’s health, offering real-time insights into deviations, instabilities, or endpoint variations. This live monitoring capability empowers fabs to take proactive measures for predictive maintenance. In addition to that, the current they measure correlates with the ion flux, providing a real-time gauge of the material deposition or etching process. Simultaneously, the voltage measurement correlates with ion energy, a critical factor in processes sensitive to variations. With 1% true accuracy, chamber-to-chamber matching and process repeatability can be established with confidence. The Moduli RF spectrometer, situated on a proximity window, collects electromagnetic field emissions from plasma, predicting endpoints for various etching and cleaning processes. The Alfven RF detector monitors RF for drifts, arcs, and pulse repeatability.
This presentation will explore the applications of these sensors for process monitoring, control, and predictive maintenance within typical process chambers in fabs.