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Created page with "=Plasma Asher 4= 400px|thumb|Plasma asher 4 in cleanroom E-5.|right Product name: PVA Tepla Gigabatch 380M<br> Year of purchase: 2024 The Plasma Asher 4 can be used for the following processes: *Photoresist stripping *Descumming *Surface cleaning *Removal of organic passivation layers and masks Plasma asher 4 has the following material restrictions: *No metals allowed *No metal oxides allowed *No III-V materials allowed The user manual, risk as..."
 
Jehem (talk | contribs)
DCH-Employees-701, NLAB-Employees-701, NLAB-LabmanagerAllUsers, danchip
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*Time (single wafer): 20-30 minutes
*Time (single wafer): 20-30 minutes
*Time (full boat): 90 minutes
*Time (full boat): 90 minutes
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==Process gas ratio for plasma asher 4 & 5==
[[File:PA_gas_mix_v3.png|400px|thumb|Ashing rate as function of gas mix ratio when processing a single 100 mm wafer and when processing a full boat with 25 wafers. The green area (~50% N<sub>2</sub>) covers the optimum range for both situations.|right]]
The ashing rate is related to the gas mix, usually expressed as percentage of nitrogen of the total amount of gas. Process development tests found that a gas mix of 50% nitrogen gives the highest ashing rate for both processing single substrates and when processing a full boat with 25 substrates.
Please note that the ashing rate for a full boat is approximately ten times slower, than the processing time for a single substrate.
{| class="wikitable"
|-
!  !! Single substrate !! Full boat
|-
! scope=row style="text-align: left;" | Test results
| Highest ashing rate at 30-80% Nitrogen || Highest ashing rate at 50-70% Nitrogen
|-
! scope=row style="text-align: left;" | Wafers
| 1 || 25
|-
! scope=row style="text-align: left;" | Wafer size
| 100 mm || 100 mm
|-
! scope=row style="text-align: left;" | Boat position
| Center of chamber || Center of chamber
|-
! scope=row style="text-align: left;" | Test wafer position
| Center of boat || Center of boat
|-
! scope=row style="text-align: left;" | Total gas flow rate
| 500 sccm || 200 sccm
|-
! scope=row style="text-align: left;" | Gas mix ratio
| Tested parameter || Tested parameter
|-
! scope=row style="text-align: left;" | Chamber pressure
| 1.25 mbar || 1.3 mbar
|-
! scope=row style="text-align: left;" | Power
| 1000 W || 1000 W
|-
! scope=row style="text-align: left;" | Test processing time
| 2 minutes || 10 minutes
|-
! scope=row style="text-align: left;" | Test average temperature
| 43°C || 47°C
|}
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==Process chamber pressure for plasma asher 4 & 5==
[[Specific Process Knowledge/Lithography/Strip/plasmaAsher04_processDevelopment|Information about process development for plasma asher 04 and plasma asher 05 can be found here.]]
[[File:PA_chamber_pressure_v3.png|400px|thumb|Ashing rate as function of chamber pressure when processing a single substrate and when processing a full boat with 25 substrates. The green area covers the optimum range (~1.3 mbar) for both situations.|right]]
The ashing rate is related to the chamber pressure during processing. Process development tests found that 1.3 mbar gives the highest ashing rate for both processing single substrates and when processing a full boat with 25 substrates.
 
Please note that the ashing rate for a full boat is approximately ten times slower, than the processing time for a single substrate.
 
{| class="wikitable"
|-
!  !! Single substrate !! Full boat
|-
! scope=row style="text-align: left;" | Test results
| Highest ashing rate at 1.3 mbar || Highest ashing rate at 1.4 mbar
|-
! scope=row style="text-align: left;" | Wafers
| 1 || 25
|-
! scope=row style="text-align: left;" | Wafer size
| 100 mm || 100 mm
|-
! scope=row style="text-align: left;" | Boat position
| Center of chamber || Center of chamber
|-
! scope=row style="text-align: left;" | Test wafer position
| Center of boat || Center of boat
|-
! scope=row style="text-align: left;" | Total gas flow rate
| 150 sccm || 200 sccm
|-
! scope=row style="text-align: left;" | Gas mix ratio
| 30% N<sub>2</sub> || 50% N<sub>2</sub>
|-
! scope=row style="text-align: left;" | Chamber pressure
| Tested parameter || Tested parameter
|-
! scope=row style="text-align: left;" | Power
| 1000 W || 1000 W
|-
! scope=row style="text-align: left;" | Test processing time
| 2 minutes || 10 minutes
|-
! scope=row style="text-align: left;" | Test average temperature
| 43°C || 55°C
|}
 
<br clear="all" />
 
==Process gas flow rate for plasma asher 4 & 5==
[[File:PA_flowRate_v4.png|400px|thumb|Ashing rate as function of total gas flow when processing a single substrate and when processing a full boat with 25 wafers. The green area covers the optimum range (~200 sccm) for both situations.|right]]
The ashing rate is related to the total gas flow rate during processing. Process development tests found that 200 sccm gives the highest ashing rate for both processing single substrates and when processing a full boat with 25 substrates. The experiments indicate that the gas flow rate has only a minor impact on the ashing rate.
 
Please note that the ashing rate for a full boat is approximately ten times slower, than the processing time for a single substrate.
 
{| class="wikitable"
|-
!  !! Single substrate !! Full boat
|-
! scope=row style="text-align: left;" | Test results
| Highest ashing rate at 200 sccm || Highest ashing rate at 200 sccm
|-
! scope=row style="text-align: left;" | Wafers
| 1 || 25
|-
! scope=row style="text-align: left;" | Wafer size
| 100 mm || 100 mm
|-
! scope=row style="text-align: left;" | Boat position
| Center of chamber || Center of chamber
|-
! scope=row style="text-align: left;" | Test wafer position
| Center of boat || Center of boat
|-
! scope=row style="text-align: left;" | Total gas flow rate
| Tested parameter || Tested parameter
|-
! scope=row style="text-align: left;" | Gas mix ratio
| 30% N<sub>2</sub> || 30% N<sub>2</sub>
|-
! scope=row style="text-align: left;" | Chamber pressure
| 1.3 mbar || 1.3 mbar
|-
! scope=row style="text-align: left;" | Power
| 1000 W || 1000 W
|-
! scope=row style="text-align: left;" | Test processing time
| 2 minutes || 10 minutes
|-
! scope=row style="text-align: left;" | Test average temperature
| 43°C || 47°C
|}
 
<br clear="all" />
 
==Process power for plasma asher 4 & 5==
[[File:PA_power_v3.png|400px|thumb|Ashing rate as function of microwave power.|right]]
The ashing rate is related to the power used during processing. Higher power increases ashing rate.
 
{| class="wikitable"
|-
!  !! Single substrate
|-
! scope=row style="text-align: left;" | Test results
| Ashing rate follows Power
|-
! scope=row style="text-align: left;" | Wafers
| 1
|-
! scope=row style="text-align: left;" | Wafer size
| 100 mm
|-
! scope=row style="text-align: left;" | Boat position
| Center of chamber
|-
! scope=row style="text-align: left;" | Test wafer position
| Center of boat
|-
! scope=row style="text-align: left;" | Total gas flow rate
| 200 sccm
|-
! scope=row style="text-align: left;" | Gas mix ratio
| 30% N<sub>2</sub>
|-
! scope=row style="text-align: left;" | Chamber pressure
| 1.3 mbar
|-
! scope=row style="text-align: left;" | Power
| Tested parameter
|-
! scope=row style="text-align: left;" | Test processing time
| 2 minutes
|-
! scope=row style="text-align: left;" | Test average temperature
| 40°C
|}
 
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==Process temperature for plasma asher 4 & 5==
[[File:PA_temperature_v2.png|400px|thumb|Ashing rate as function of temperature.|right]]
The ashing rate is related to the temperature during processing. Higher temperature increases ashing rate.
 
{| class="wikitable"
|-
!  !! Single substrate
|-
! scope=row style="text-align: left;" | Test results
| Ashing rate follows temperature
|-
! scope=row style="text-align: left;" | Wafers
| 1
|-
! scope=row style="text-align: left;" | Wafer size
| 100 mm
|-
! scope=row style="text-align: left;" | Boat position
| Center of chamber
|-
! scope=row style="text-align: left;" | Test wafer position
| Center of boat
|-
! scope=row style="text-align: left;" | Total gas flow rate
| 200 sccm
|-
! scope=row style="text-align: left;" | Gas mix ratio
| 30% N<sub>2</sub>
|-
! scope=row style="text-align: left;" | Chamber pressure
| 1.3 mbar
|-
! scope=row style="text-align: left;" | Power
| 1000 W
|-
! scope=row style="text-align: left;" | Test processing time
| 2 minutes
|-
! scope=row style="text-align: left;" | Test average temperature
| Tested parameter
|}
 
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==Comparison of ashing rate between substrate sizes for plasma asher 4 & 5==
[[File:PA_comparison_v3.png|400px|thumb|Comparison of ashing rate with different substrate sizes. Process was done using a single substrate placed in the middle of the glass boat, which was placed in the center of the chamber.|right]]
The ashing rate is highest for 100 mm substrates, lower for 150 mm substrates and even lower for 200 mm substrates.
 
All substrate sizes follows the same pattern:
*Ashing rate increases with a higher percentage nitrogen in the gas mix
*Ashing rate increases with a higher chamber pressure
*The total gas flow has only little influence on the ashing rate, but <i>slightly</i> favors the lower flow rate of 200 sccm, similar to previous experiment results
 
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'''Process parameter impact on ashing rate'''<br>
Investigating the ashing rate using linear regression models on the process parameters, indicates that the gas mix and the chamber pressure has a significant impact on the ashing rate, while the gas flow has only little effect:
<gallery mode="packed-hover" heights="150">
ParamEffect_100_mm_v1.png|100 mm parameter impact
ParamEffect_150_mm_v1.png|150 mm parameter impact
ParamEffect_200_mm_v1.png|200 mm parameter impact
</gallery>
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