Martin Dummermuth, Bird Technologies, Solon, OH
In plasma-based semiconductor processes there are many problems that are intermittent in nature and therefore very difficult to detect. Due to the difficulty of detection, these problems are often discovered only after many wafers have been compromised, resulting in significant financial loss.
These issues can include incorrect match set point, match degradation, parasitic plasma, ac-line power fluctuation, cable failure, arcing on the electrode, arcing in the ground plane, and sputter target arcing.
Through advancements in signal processing techniques, these notoriously elusive events can now be reliably detected through high-speed analysis of the voltage and current waveforms that are feeding the plasma.
This paper will discuss methods that can be used to detect intermittent issues, classify them into various categories, and provide actionable information for process interdiction, allowing for reduction in wafer loss and tool down-time.