Specific Process Knowledge/Etch/DRIE-Pegasus/picoscope: Difference between revisions
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Process A has 4 second dep phase and 7 second (1.5 second break and 5.5 second main) and the SPTS Pro software samples the process parameters every 0.5 second. This produces plots as seen above where all measurements have markers. One can ask the questions: | Process A has 4 second dep phase and 7 second (1.5 second break and 5.5 second main) and the SPTS Pro software samples the process parameters every 0.5 second. This produces plots as seen above where all measurements have markers. One can ask the questions: | ||
# What happens if the cycle duration is lowered in order produce smaller scallops? | # What happens if the cycle duration is lowered in order produce smaller scallops? | ||
# | # How do we know if something that is very brief happens? For instance, spikes in reflected power can be rather short lived as indicated by the one point spikes of reflected coil power above. | ||
In both cases, the sampling frequency of 2 Hz is simply not high enough - we need to increase this. The SPTS Pro software can only lower this. However, realizing that all the devices (mass flow controllers, pressure gauges, RF generators etc.) responsible for the parameters in the plot above are produce output measurements in real time, we can sample these parameters by some external device. Enter the Picoscope oscilloscope with 8 analog channels that enable us sample up to 8 outputs, usually a DC voltage, at almost any sampling rate. We therefore have to decide which parameters are most important to monitor and then go through the electrical diagrams to find an appropriate place to pick up the signal. | |||
This set of parameters will | |||