Specific Process Knowledge/Thin film deposition/Furnace LPCVD Nitride: Difference between revisions
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<i> Unless otherwise stated, this page is written by <b>DTU Nanolab internal</b></i> | |||
[[Category: Equipment|Thin film F]] | [[Category: Equipment|Thin film F]] | ||
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==Deposition of Silicon Nitride using LPCVD== | ==Deposition of Silicon Nitride using LPCVD== | ||
DTU Nanolab has two LPCVD (Low Pressure Chemical Vapour Deposition) furnaces <!--[[Specific Process Knowledge/Thin film deposition/B2 Furnace LPCVD Nitride|LPCVD furnaces]]--> for deposition of silicon nitride: | |||
*A 4" furnace (installed in 1995) for deposition og stoichiometric nitride on 4 inch wafers. | |||
*A 6" furnace (installed in 2008) for deposition of low stress/silicon rich nitride on 4 inch and 6 inch wafers. Deposition of stoichiometric nitride on 4 inch wafers is also allowed in this furnace. | |||
In LabManager the two furnaces are named "Furnace: LPCVD nitride (4") (B2)" and "Furnace: LPCVD nitride (6") (E3)", respectively. Both furnaces are Tempress horizontal furnaces. | |||
Please check the cross contamination information in LabManager before you use any of the two furnaces. | |||
The LPCVD silicon nitride deposition is a batch process, where nitride can be deposited on a batch of up to 15 wafers (in the 4" nitride furnace) or 25 wafers (in the 6" nitride furnace) at a time. The deposition takes place under vacuum (120-200 mTorr, depending on the process) and at high temperature (780-845 C, depending on the process). The reactive gases are ammonia (NH<sub>3</sub>) and dichlorsilane (SiH<sub>2</sub>Cl<sub>2</sub>). | |||
The LPCVD nitride has a very good step coverage, and the film thickness is very uniform over the wafers. | |||
'''The user manuals, quality control procedures and results, user APVs, technical information and contact information can be found in LabManager:''' | '''The user manuals, quality control procedures and results, user APVs, technical information and contact information can be found in LabManager:''' | ||
[http://labmanager | [http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=84 4" LPCVD nitride furnace (B2)] | ||
[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=250 6" LPCVD nitride furnace (E3)] | |||
[https://labmanager.dtu.dk/d4Show.php?id=1926 Furnace computer manual] | |||
== Manual for the furnace computer to the A, B, C and E stack furnaces == | |||
The A, B, C and E stack furnaces can be controlled either from a touch screen by each furnace or from a furnace computer. The user manual for the furnace computer can be found here: | |||
[ | [[media:Furnace_computer_manual.pdf|Manual for furnace computers for the A, B, C and E stack furnaces]] | ||
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== Process information == | == Process information == | ||
*[[/Deposition of stoichiometric nitride using the 4" LPCVD nitride furnace|Deposition of stoichiometric nitride using the 4" LPCVD nitride furnace]] | *[[/Deposition of stoichiometric nitride using the 4" LPCVD nitride furnace|Deposition of stoichiometric nitride using the 4" LPCVD nitride furnace]] | ||
*[[/Deposition of | *[[/Deposition of low stress nitride using the 4" LPCVD nitride furnace|Deposition of low stress nitride using the 4" LPCVD nitride furnace <span style="color:Red">(Low stress nitride depositions are no longer available in this furnace - use the 6" nitride furnace instead)</span>]] | ||
*[[/Deposition of low stress nitride using the 6" LPCVD nitride furnace|Deposition of low stress nitride using the 6" LPCVD nitride furnace ]] | *[[/Deposition of low stress nitride using the 6" LPCVD nitride furnace|Deposition of low stress nitride using the 6" LPCVD nitride furnace ]] | ||
*[[/Deposition of stoichiometric nitride using the 6" LPCVD nitride furnace|Deposition of stoichiometric nitride using the 6" LPCVD nitride furnace <span style="color:Red">(4" wafers need a special permission using as a back up of 4" LPCVD nitride furnace, B2)</span>]] | |||
*[[/Using LPCVD silicon nitride as a masking material for KOH etching|Using LPCVD silicon nitride as a masking material for KOH etching]] | *[[/Using LPCVD silicon nitride as a masking material for KOH etching|Using LPCVD silicon nitride as a masking material for KOH etching]] | ||
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|style="background:WhiteSmoke; color:black"| | |style="background:WhiteSmoke; color:black"| | ||
*Silicon rich (low stress) nitride | *Silicon rich (low stress) nitride | ||
* | *Stoichiometric nitride | ||
|style="background:WhiteSmoke; color:black"| | |style="background:WhiteSmoke; color:black"| | ||
*Stoichiometric nitride | *Stoichiometric nitride | ||
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|style="background:LightGrey; color:black"|Temperature | |style="background:LightGrey; color:black"|Temperature | ||
|style="background:WhiteSmoke; color:black"| | |style="background:WhiteSmoke; color:black"| | ||
* | *810-845 <sup>o</sup>C | ||
The temperature vary over the furnace tube | The temperature vary over the furnace tube | ||
|style="background:WhiteSmoke; color:black"| | |style="background:WhiteSmoke; color:black"| | ||
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<!--hide text | <!--hide text | ||
==Using LPCVD silicon nitride as a masking material for KOH etching== | ==Using LPCVD silicon nitride as a masking material for KOH etching== | ||
Stoichiometric silicon nitride is mainly used as masking material for potassium hydroxide (KOH) etching. The etch rate of the nitride in 80 <sup>o</sup>C KOH is expected to be less than 1 Å/min. | |||
There are regularly users having problems with pinholes in the silicon nitride after KOH etching. It is not always clear what the reasons are, but we suspect problems can arise due to | There are regularly users having problems with pinholes in the silicon nitride after KOH etching. It is not always clear what the reasons are, but we suspect problems can arise due to | ||
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'''To avoid too many or too large particles in the nitride'''<br\> | '''To avoid too many or too large particles in the nitride'''<br\> | ||
*If possible, use the new nitride furnace to deposit stoichiometric nitride. In order to avoid problems with particles it is not allowed to deposit low stress nitride in this furnace, and the particles level is therefore low compared to the older nitride furnace. | *If possible, use the new nitride furnace to deposit stoichiometric nitride. In order to avoid problems with particles it is not allowed to deposit low stress nitride in this furnace, and the particles level is therefore low compared to the older nitride furnace. | ||
*Before running a process keep in close contact with the | *Before running a process keep in close contact with the Nanolab staff (especially the process specialist on the furnace) or take a look at the logbook to make sure that the nitride furnace is expected to be in a good state. | ||
'''To avoid too rough handling of the wafers after the nitride deposition'''<br\> | '''To avoid too rough handling of the wafers after the nitride deposition'''<br\> | ||
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*It is recommended to have a of silicon oxide layer between the silicon substrate and the nitride layer to reduce the stress level between the layers. The silicon nitride is then expected to have less tendency to break. | *It is recommended to have a of silicon oxide layer between the silicon substrate and the nitride layer to reduce the stress level between the layers. The silicon nitride is then expected to have less tendency to break. | ||
hide text--> | hide text--> | ||
== Rules for storage and RCA cleaning of wafers to the B2 and E3 furnaces == | |||
*[[Specific_Process_Knowledge/Thermal_Process/Storage_and_cleaning_of_wafer_to_the_A,_B,_C_and_E_stack_furnaces|Storage and cleaning of wafer to the B2 and E3 furnaces]] |
Latest revision as of 09:31, 6 February 2024
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Unless otherwise stated, this page is written by DTU Nanolab internal
Deposition of Silicon Nitride using LPCVD
DTU Nanolab has two LPCVD (Low Pressure Chemical Vapour Deposition) furnaces for deposition of silicon nitride:
- A 4" furnace (installed in 1995) for deposition og stoichiometric nitride on 4 inch wafers.
- A 6" furnace (installed in 2008) for deposition of low stress/silicon rich nitride on 4 inch and 6 inch wafers. Deposition of stoichiometric nitride on 4 inch wafers is also allowed in this furnace.
In LabManager the two furnaces are named "Furnace: LPCVD nitride (4") (B2)" and "Furnace: LPCVD nitride (6") (E3)", respectively. Both furnaces are Tempress horizontal furnaces.
Please check the cross contamination information in LabManager before you use any of the two furnaces.
The LPCVD silicon nitride deposition is a batch process, where nitride can be deposited on a batch of up to 15 wafers (in the 4" nitride furnace) or 25 wafers (in the 6" nitride furnace) at a time. The deposition takes place under vacuum (120-200 mTorr, depending on the process) and at high temperature (780-845 C, depending on the process). The reactive gases are ammonia (NH3) and dichlorsilane (SiH2Cl2).
The LPCVD nitride has a very good step coverage, and the film thickness is very uniform over the wafers.
The user manuals, quality control procedures and results, user APVs, technical information and contact information can be found in LabManager:
Manual for the furnace computer to the A, B, C and E stack furnaces
The A, B, C and E stack furnaces can be controlled either from a touch screen by each furnace or from a furnace computer. The user manual for the furnace computer can be found here:
Manual for furnace computers for the A, B, C and E stack furnaces
Process information
- Deposition of stoichiometric nitride using the 4" LPCVD nitride furnace
- Deposition of low stress nitride using the 4" LPCVD nitride furnace (Low stress nitride depositions are no longer available in this furnace - use the 6" nitride furnace instead)
- Deposition of low stress nitride using the 6" LPCVD nitride furnace
- Deposition of stoichiometric nitride using the 6" LPCVD nitride furnace (4" wafers need a special permission using as a back up of 4" LPCVD nitride furnace, B2)
Equipment | 6" LPCVD nitride furnace (E3) | 4" LPCVD nitride furnace (B2) | |
---|---|---|---|
Purpose | Deposition of |
|
|
Performance | Step coverage |
|
|
Film quality |
|
| |
Process parameter range | Temperature |
The temperature vary over the furnace tube |
The temperature vary over the furnace tube |
Pressure |
|
| |
Gas flows |
For Low stress nitride
For Stoichiometric nitride on 6" wafers
|
The gas flows depend on whether nitride is deposited on 4" or 6" wafers | |
Substrates | Batch size |
Including a test wafer |
Including a test wafer |
Allowed materials |
|
|