Specific Process Knowledge/Thermal Process/Furnace: Multipurpose annealing: Difference between revisions

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-==From February 2024: RESIST PYROLYSIS FURNACE==
 '''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Thermal_Process/Furnace:_Multipurpose_annealing#Multipurpose_annealing_furnace click here]'''
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 [[Image:ATV_ovn_boat.jpg|thumb|335x335px|Boat with wafers for the Resist Pyrolysis furnace. Photo: DTU Nanolab internal]]
-The Resist Pyrolysis furnace it made by ATV Technologie, and it was installed in the cleanroom in November 2014.
+The Resist Pyrolysis furnace it made by ATV Technologie, and it was installed in the cleanroom in January 2015.
 In November 2024 the furnace was repaired by ATV Technologie. At the repair, the whole furnace body was changed, and all heaters were replaced. Also, the process exhaust flow was decreased by changing a valve in the exhaust line.
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 The Resist Pyrolysis furnace is a research tool. It means, that it is mainly available for users working on certain research projects, especially in the Biomaterial Microsystems Group at DTU Nanolab.
-The furnace is mainly being used for resist pyrolysis. It can also be used for annealing in nitrogen (N<sub>2</sub>) and oxidation with oxygen (O<sub>2</sub>), but O<sub>2</sub> is mostly used for cleaning of the furnace after resist pyrolysis processes.
+The furnace is mainly being used for resist pyrolysis. It can also be used for annealing in nitrogen (N<sub>2</sub>) (or forming gas, i.e. up to 4% H<sub>2</sub> mixed with N<sub>2</sub>, but this has not been tested) and oxidation with oxygen (O<sub>2</sub>), but O<sub>2</sub> is mostly used for cleaning of the furnace after resist pyrolysis processes.
-Process steps can run either at atmospheric pressure or in vacuum. A small N<sub>2</sub> or O<sub>2</sub> flow (up to 2 slm) can be applied in vacuum steps.
+For resist pyrolysis, samples with different resist layers are heated up to maximum 1050 <sup>o</sup>C in a nitrogen atmosphere. At high temperatures carbon is formed by pyrolysis of the resist. In this way conductive structures can be made from a resist patterned sample. If oxygen from the air or from outgassing of the resist is present in the furnace, the resist layer will be removed, thus it is important to evacuate the furnace and flush it with nitrogen, before a high temperature for resist pyrolysis is obtained. Pyrolysis of a large amount of resist may also be a problem due to resist outgassing.
+Process steps can run either at atmospheric pressure or in vacuum. A small N<sub>2</sub> or O<sub>2</sub> flow (up to 2 SLM) can be applied in vacuum steps.
 The quartz parts in the furnace (the furnace tube, the door sealing and the wafer boat) can be changed, depending on what processes and samples the furnace is used for, but it has been decided that a quartz set for resist resist pyrolysis will be mounted in the furnace all the time. This limits the number of materials that are allowed in the furnace.
-Please note that all new resist and other materials have to be approved by the Thin Film group (thinfilm@nanolab.dtu.dk) before they are allowed in the furnace.
+Please note that all new resist types and other materials have to be approved by the Thin Film group (thinfilm@nanolab.dtu.dk) before they are allowed in the furnace.
 All process gases (except purge nitrogen) are heated, before they are introduced into the furnace at the door side.
-The furnace tube is heated by use of 12 long heaters situated along the furnace tube and combined in three groups (top, bottom left and bottom right) and two flat heaters situated in the ends of the furnace tube. The this way the temperature will be very uniform everywhere in the furnace tube. The heating can be done very fast, up to 30 <sup>o</sup>C/min. The maximum allowed process temperature is normally 1050 <sup>o</sup>C, however up to 1100 <sup>o</sup>C without vacuum is possible. The maximum allowed process time at 1050 <sup>o</sup>C is 3 hours.
+The furnace tube is heated by use of 12 long heaters situated along the furnace tube and combined in three groups (top, bottom left and bottom right) and two flat heaters situated in the ends of the furnace tube. This ensures that the temperature will be very uniform everywhere in the furnace tube. The heating can be done very fast, up to 30 <sup>o</sup>C/min. The maximum allowed process temperature is normally 1050 <sup>o</sup>C, however up to 1100 <sup>o</sup>C without vacuum is possible. The maximum allowed process time at 1050 <sup>o</sup>C is 3 hours.
-The furnace body surrounding the furnace tube consists of a top and bottom half-shell. To cool down the furnace (when the temperature is below 800 <sup>o</sup>C), the top half shelf can be lifted up, and cooling fans will then flow air from the surroundings around the furnace tube to cool it down. However, for safety reasons, the cooling fans will not the activated when there is hydrogen in the furnace, and cooling will then be very slow.
-It is not possible to open the furnace when the temperature is above 300 <sup>o</sup>C.
+The furnace body surrounding the furnace tube consists of a top and bottom half-shell. To cool down the furnace (when the temperature is below 800 <sup>o</sup>C and not for processes with H<sub>2</sub>), the top half shelf can be lifted up, and cooling fans will then flow air from the surroundings around the furnace tube to cool it down.
-For resist pyrolysis, samples with different resist layers are heated up to maximum 1050 <sup>o</sup>C in a nitrogen atmosphere. At high temperatures carbon is formed by pyrolysis of the resist. In this way conductive structures can be made from a resist patterned sample. If oxygen from the air or from outgassing of the resist is present in the furnace, the resist layer will be removed, thus it is important to evacuate the furnace and flush it with nitrogen, before a high temperature for resist pyrolysis is obtained. Pyrolysis of a large amount of resist may also be a problem due to resist outgassing.
+It is not possible to open the furnace, when the temperature is above 300 <sup>o</sup>C.
 '''The user manual, technical information and contact information can be found in LabManager:'''
-'''[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=340 Furnace: Multipurpose annealing]'''
+'''[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=340 Resist Pyrolysis furnace]'''
 ==Process information==
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 *Annealing: look at the [[Specific Process Knowledge/Thermal Process/Annealing|Annealing]] page
 *[[Specific_Process_Knowledge/Thermal_Process/Furnace:_Multipurpose_annealing/Acceptance test|Results from the Resist Pyrolysis furnace acceptance test]]
-*[[Specific_Process_Knowledge/Thermal_Process/Pyrolysis/Pyrolysis_with_Multipurpose_Anneal_Furnace|Pyrolysis]]
+*[[Specific_Process_Knowledge/Thermal_Process/Pyrolysis/Pyrolysis_with_Multipurpose_Anneal_Furnace|Resist pyrolysis]]
 ==Overview of the performance of the ATV furnace and process related parameters==
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 |style="background:WhiteSmoke; color:black"|
 *Pyrolysis of different resists
+*Annealing in N<sub>2</sub>
+*Annealing in forming gas (up to 5% H<sub>2</sub> mixed with N<sub>2</sub>) - Not tested
 *Dry oxidation of silicon
-*Annealing in N<sub>2</sub>,
-*Annealing in forming gas (up to 5% H<sub>2</sub> mixed with N<sub>2</sub>) - Needs to be tested
 |-
 !style="background:silver; color:black" align="center"|Performance
 |style="background:LightGrey; color:black"|Film thickness
 |style="background:WhiteSmoke; color:black"|
-*Dry oxidation: 50 Å  to ~200 nm SiO<sub>2</sub> (it takes too long to grow a thicker oxide layer)
+*Dry oxidation of silicon: 50 Å  to ~200 nm SiO<sub>2</sub> (it takes too long to grow a thicker oxide layer)
 |-
 !style="background:silver; color:black" align="center" valign="center" rowspan="4"|Process parameter range
-|style="background:LightGrey; color:black"|Process Temperature
+|style="background:LightGrey; color:black"|Process temperature
 |style="background:WhiteSmoke; color:black"|
 *No vacuum: Room temperature - 1100 <sup>o</sup>C - Normally maximum 1050 <sup>o</sup>C allowed
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 |style="background:WhiteSmoke; color:black"|
 *Atmospheric pressure
-*Vacuum down to ~0.1 mbar (gas flow dependent)
+*Vacuum: Pressure down to ~0.1 mbar (gas flow dependent)
 |-
 |style="background:LightGrey; color:black"|Gases on the system
 |style="background:WhiteSmoke; color:black"|
 Atmospheric pressure:
-*N<sub>2</sub>: 20 slm - Maximum 10 SLM recommended (to protect the heaters)
+*N<sub>2</sub>: 20 SLM - Maximum 10 SLM recommended (to protect the heaters)
-*O<sub>2</sub>: 10 slm
+*O<sub>2</sub>: 10 SLM
-*H<sub>2</sub>: 5 slm - Not allowed
+*H<sub>2</sub>: 5 SLM - Not allowed
-*N<sub>2</sub> mix : 10 slm (for forming gas H<sub>2</sub>-N<sub>2</sub> gas mixture) - Not tested and not allowed for vacuum processes
+*N<sub>2</sub> mix: 10 SLM (for forming gas, i.e. up to 5% H<sub>2</sub> mixed with N<sub>2</sub>) - Not tested
 Vacuum:
-*N<sub>2</sub>: 2 slm
+*N<sub>2</sub>: 2 SLM
-*O<sub>2</sub>: 2 slm
+*O<sub>2</sub>: 2 SLM
 *H<sub>2</sub>: Not allowed
 *N<sub>2</sub> mix : Not allowed
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 |style="background:LightGrey; color:black"|Substrate materials allowed
 |style="background:WhiteSmoke; color:black"|
-*Depends on the quartz set
+*Normally only samples for resist pyrolysis approved by Nanolab
 |-
 |}