Specific Process Knowledge/Etch/DRIE-Pegasus/picoscope: Difference between revisions
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Minimizing the reflected power is essential to ensure that the instrument hardware doesn't degrade over time and that the users have accurate information about the processes. Realizing that there may be a challenge with detecting reflected powers we need to decide what to do. We can abandon all processes and start developing new ones - this will halt all processing. Instead, a set of new recipes will be developed. | Minimizing the reflected power is essential to ensure that the instrument hardware doesn't degrade over time and that the users have accurate information about the processes. Realizing that there may be a challenge with detecting reflected powers we need to decide what to do. We can abandon all processes and start developing new ones - this will halt all processing. Instead, a set of new recipes will be developed. | ||
==== | ==== Stabilize the pressure ==== | ||
Changing the pressure in the plasma has a great impact on the RF matching conditions as illustrated for [[Specific_Process_Knowledge/Etch/DRIE-Pegasus/System-description#Why_RF_matching_is_extremely_important_in_the_Bosch_process | an oxygen plasma]] elsewhere. The obvious place to start is therefore the pressure. Also, it barely makes sense to claim that the pressure is 20 mtorr in the dep phase if it oscillates as shown for the Process D4 above. | Changing the pressure in the plasma has a great impact on the RF matching conditions as illustrated for [[Specific_Process_Knowledge/Etch/DRIE-Pegasus/System-description#Why_RF_matching_is_extremely_important_in_the_Bosch_process | an oxygen plasma]] elsewhere. The obvious place to start is therefore the pressure. Also, it barely makes sense to claim that the pressure is 20 mtorr in the dep phase if it oscillates as shown for the Process D4 above. | ||
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To get rid of the oscillations we must change from the Fixed pressure mode must to Fixed APC mode. Here, this is no feedback loop: In the transition between phases, the different gas flows, RF powers and APC setting will produce a different pressure that is reached without any overshooting. The price one may have to pay is that the new pressure may be reached at a slower speed. Also, with a pressure setting defined in terms of APC percentage in the recipe, the actual pressures during the process itself will have to be noted manually. | To get rid of the oscillations we must change from the Fixed pressure mode must to Fixed APC mode. Here, this is no feedback loop: In the transition between phases, the different gas flows, RF powers and APC setting will produce a different pressure that is reached without any overshooting. The price one may have to pay is that the new pressure may be reached at a slower speed. Also, with a pressure setting defined in terms of APC percentage in the recipe, the actual pressures during the process itself will have to be noted manually. | ||
==== Picoscope examples ==== | |||
Using the Picoscope is straightforward. The Start/Stop recording buttons are located in the lower left corner of the GUI; the recording has to be done manually. The settings in the top of the GUI | |||
[[image:PicoSetup.PNG|500px]] | |||
are usually: | |||
= New recipes= | = New recipes= | ||