Thomas Gilmore - Video Lecture

Thomas Gilmore - Video Lecture

IVS-IPSTA 2020 Online Conference December 13, 2020

Materials Assembly & Sensors Session
Session chair:
Amit Sitt

Tel Aviv University

On modern fault detection methods for industrial plasmas using intelligent sensors

Thomas Gilmore

Impedans Ltd., City Junction Business Park,
Northern Cross, Dublin, Ireland


Radio-frequency (RF) voltage-current (VI) probes, mounted between the matching network and plasma, can accurately detect plasma impedance changes at the fundamental and harmonic frequencies. The plasma impedance is very sensitive to any electrical, chemical, mechanical and/or geometrical changes that may occur in the reactor. The non-linear nature of the plasma impedance generates a rich harmonic spectrum, accurate measurement of which can be used to precisely detect faults that affect the workpiece being processed, faults that usually lead to a scrappage event.

With modern process windows getting narrower and narrower, the semiconductor industry now realises that standard fault detection methods and controls are no longer satisfactory. They have also found that moving plasma recipes from R&D to a production environment is becoming incredibly difficult. This work will present several case studies for successes in semiconductor and biomedical industries where using impedance and harmonic data resulted in significant cost savings.

In addition to VI probes for live monitoring, “sensorized” wafers for quick tool qualification and process matching can directly measure the ions as seen by the substrate. This talk will present some insights from fundamental research using in-situ Ion Energy Distribution Function measurements and will introduce a new “wireless” Ion Energy Wafer for use in semiconductor production fabs.