Specific Process Knowledge/Etch/DRIE-Pegasus/Pegasus-2/OldConfig

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Past configurations

Configuration and setup valid March 2021 to August 2021

Currently valid from March 15 2021 onwards

Item	The currently applied modification	Comments
Available gasses and gas chemistry	Available gasses: SF6: 50 sccm O2: 50 sccm Ar: 283 N2: 500 sccm He: 11 sccm Not available: C4F8 (H2 currently fitted but closed) : 0 sccm CO2: (It is not in the software)	OnlySF6 and O2 are used for Si, PR, and Cr etch. The rest is only make-up
Plasma source heaters	Applies to Plenum Heater Inner Heater Magnetic Confinement Heater Chamber Heater	The temperature on the heaters in the plasma source are set to 20 degrees with a high tolerance. This essentially corresponds to powered off compared to default Pegasus temperatures which are in the 120-140 degrees range. Always make sure that the temperature settings in the recipes are not enabled. Click here to have more information.
RF power and pressure settings	All recipes run without coil power, very low platen power and low pressures	None of the recipes use coil power in order to prevent aluminium fluoride formation at the aluminium oxide dome. These particles may drop on the wafer or chuck and cause abnormalitites. Most of the recipes rely on very low pressure and low power - 0.2 mTorr and 10 Watt platen power is not an error and easily supports the plasma.
Carbon free plasmas	The process chamber does not have any carbon containing etch gasses. Therefore, polymer build-up on the chamber walls is not an issue. The 'carbon free' policy does not, however, apply to the choice of masking materials and CSAR, AZ and DUV resists are allowed.
Chamber conditioning and cleaning	Running long oxygen cleans is not necessary and must be avoided. Neither are shorter cleans between wafers.	The absence of carbon containing etch gasses ensures that the process chamber is kept clean.
Approved recipes	The 'std' folder holds the list of currently allowed recipes	Recipes in other folders may no longer be safe to run.
Etch of nickel and chromium	Recipes for etching nickel and chromium have been developed	The cross contamination consequences have yet to be determined
Background knowledge required for safe operation	Users and supervisors of Pegasus-2 should carefully read the 3 papers listed in the comments in order to have a correct understanding of the etch process and experimental procedure and how it relates to the Bosch etch performance.	Papers: On the formation of black silicon in SF6-O2 plasma: The clear, oxidize, remove, and etch (CORE) sequence and black silicon on demand The CORE Sequence: A Nanoscale Fluorocarbon-Free Silicon Plasma Etch Process Based on SF6/O2 Cycles with Excellent 3D Profile Control at Room Temperature Ultrahigh aspect ratio etching of silicon in SF6-O2 plasma: The clear-oxidize-remove etch (CORE) sequence and chromium mask

Configuration and setup valid November 2020 to March 2021

Currently valid from November 2020 onwards

Item	The currently applied modification	Comments
Available gasses and gas chemistry	Available gasses: SF6: 50 sccm O2: 50 sccm Ar: 283 N2: 500 sccm He: 11 sccm Not available: C4F8 (H2 currently fitted but closed) : 0 sccm CO2: (It is not in the software)	OnlySF6 and O2 are used for Si, PR, and Cr etch. The rest is only make-up
Plasma source heaters	Applies to Plenum Heater Inner Heater Magnetic Confinement Heater Chamber Heater	The temperature on the heaters in the plasma source are set to 20 degrees with a high tolerance. This essentially corresponds to powered off compared to default Pegasus temperatures which are in the 120-140 degrees range. Always make sure that the temperature settings in the recipes are not enabled. Click here to have more information.
RF power and pressure settings	All recipes run without coil power, very low platen power and low pressures	None of the recipes use coil power in order to prevent aluminium fluoride formation at the aluminium oxide dome. These particles may drop on the wafer or chuck and cause abnormalitites. Most of the recipes rely on very low pressure and low power - 0.2 mTorr and 10 Watt platen power is not an error and easily supports the plasma.
Carbon free plasmas	The process chamber does not have any carbon containing etch gasses. Therefore, polymer build-up on the chamber walls is not an issue. The 'carbon free' policy does not, however, apply to the choice of masking materials and CSAR, AZ and DUV resists are allowed.
Chamber conditioning and cleaning	Running long oxygen cleans is not necessary and must be avoided. Neither are shorter cleans between wafers.	The absence of carbon containing etch gasses ensures that the process chamber is kept clean.
Approved recipes	The 'std' folder holds the list of currently allowed recipes	Recipes in other folders may no longer be safe to run.
Etch of nickel and chromium	Recipes for etching nickel and chromium have been developed	The cross contamination consequences have yet to be determined

As of December 2020 there is not yet any old configurations.

Access to Pegasus 2 configuration templates

Pegasus 2 configuration table version 1

• Table header: Template:Peg2configheader1

• Table content: Template:Peg2configcontent1