'''NB: Use dedicated descum asher Plasma Asher 3: Descum for descumming.'''
'''NB: Use dedicated descum asher Plasma Asher 3: Descum for descumming.'''
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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"
|-
! Test setup !! Single substrate !! Full boat
|-
! scope=row| Test results
| Highest ashing rate at 30-80% Nitrogen || Highest ashing rate at 50-70% Nitrogen
|-
! scope=row| Wafers
| 1 || 25
|-
! scope=row| Wafer size
| 100 mm || 100 mm
|-
! scope=row| Boat position
| Center of chamber || Center of chamber
|-
! scope=row| Test wafer position
| Center of boat || Center of boat
|-
! scope=row| Total gas flow rate
| 500 sccm || 200 sccm
|-
! scope=row| Gas mix ratio
| Tested parameter || Tested parameter
|-
! scope=row| Chamber pressure
| 1.25 mbar || 1.3 mbar
|-
! scope=row| Power
| 1000 W || 1000 W
|-
! scope=row| Test processing time
| 2 minutes || 10 minutes
|-
! scope=row| Test average temperature
| 43°C || 47°C
|}
<br clear="all" />
==Process chamber pressure for plasma asher 4 & 5==
[[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"
|-
! Test setup !! Single substrate !! Full boat
|-
! scope=row| Test results
| Highest ashing rate at 1.3 mbar || Highest ashing rate at 1.4 mbar
|-
! scope=row| Wafers
| 1 || 25
|-
! scope=row| Wafer size
| 100 mm || 100 mm
|-
! scope=row| Boat position
| Center of chamber || Center of chamber
|-
! scope=row| Test wafer position
| Center of boat || Center of boat
|-
! scope=row| Total gas flow rate
| 150 sccm || 200 sccm
|-
! scope=row| Gas mix ratio
| 30% N<sub>2</sub> || 50% N<sub>2</sub>
|-
! scope=row| Chamber pressure
| Tested parameter || Tested parameter
|-
! scope=row| Power
| 1000 W || 1000 W
|-
! scope=row| Test processing time
| 2 minutes || 10 minutes
|-
! scope=row| 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"
|-
! Test setup !! Single substrate !! Full boat
|-
! scope=row| Test results
| Highest ashing rate at 200 sccm || Highest ashing rate at 200 sccm
|-
! scope=row| Wafers
| 1 || 25
|-
! scope=row| Wafer size
| 100 mm || 100 mm
|-
! scope=row| Boat position
| Center of chamber || Center of chamber
|-
! scope=row| Test wafer position
| Center of boat || Center of boat
|-
! scope=row| Total gas flow rate
| Tested parameter || Tested parameter
|-
! scope=row| Gas mix ratio
| 30% N<sub>2</sub> || 30% N<sub>2</sub>
|-
! scope=row| Chamber pressure
| 1.3 mbar || 1.3 mbar
|-
! scope=row| Power
| 1000 W || 1000 W
|-
! scope=row| Test processing time
| 2 minutes || 10 minutes
|-
! scope=row| 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"
|-
! Test setup !! Single substrate
|-
! scope=row| Test results
| Ashing rate follows temperature
|-
! scope=row| Wafers
| 1
|-
! scope=row| Wafer size
| 100 mm
|-
! scope=row| Boat position
| Center of chamber
|-
! scope=row| Test wafer position
| Center of boat
|-
! scope=row| Total gas flow rate
| 200 sccm
|-
! scope=row| Gas mix ratio
| 30% N<sub>2</sub>
|-
! scope=row| Chamber pressure
| 1.3 mbar
|-
! scope=row| Power
| 1000 W
|-
! scope=row| Test processing time
| 2 minutes
|-
! scope=row| Test average temperature
| Tested parameter
|}
<br clear="all" />
==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"
|-
! Test setup !! Single substrate
|-
! scope=row| Test results
| Ashing rate follows power
|-
! scope=row| Wafers
| 1
|-
! scope=row| Wafer size
| 100 mm
|-
! scope=row| Boat position
| Center of chamber
|-
! scope=row| Test wafer position
| Center of boat
|-
! scope=row| Total gas flow rate
| 200 sccm
|-
! scope=row| Gas mix ratio
| 30% N<sub>2</sub>
|-
! scope=row| Chamber pressure
| 1.3 mbar
|-
! scope=row| Power
| Tested parameter
|-
! scope=row| Test processing time
| 2 minutes
|-
! scope=row| Test average temperature
| 40°C
|}
<br clear="all" />
==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
<br clear="all" />
'''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>
<br clear="all" />
=Plasma Asher 1=
=Plasma Asher 1=
Revision as of 13:09, 26 February 2025
The content on this page, including all images and pictures, was created by DTU Nanolab staff, unless otherwise stated.
Product name: Diener Pico Plasma Asher
Year of purchase: 2014
The Plasma Asher 3: Descum is dedicated for resist descum, i.e. removal of remains resist traces after development. It has a small chamber, so you can only load a single 100 mm substrate, or a few smaller pieces.
In this machine, only Oxygen is used for processing.
Typical process parameters:
Process: Photoresist descumming
Pressure: 0.2-0.8 mbar
Gas: 45 sccm O2
Power: 100%
Time: 1 -10 minutes (depending on photoresist type and thickness)
Other materials have not been tested.
The user manual, user APV, and contact information can be found in LabManager - requires login
Process Information
Detailed information about descum processing on Plasma asher 3: Descum can be found here.
Plasma Asher 4
Plasma asher 4 in cleanroom E-5.
Product name: PVA Tepla Gigabatch 380M
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 assessment, and contact information can be found in LabManager - requires login
Plasma Asher 5
Plasma asher 5 in cleanroom E-5.
Product name: PVA Tepla Gigabatch 380M
Year of purchase: 2024
The Plasma Asher 5 can be used for the following processes:
Photoresist stripping
Descumming
Surface cleaning
Removal of organic passivation layers and masks
Furthermore plasma processing using CF4 in plasma asher 5 can be used for:
Etching of glass and ceramic
Etching of SiO2, Si3N4, Si
Removal of polyimide layers
Typical stripping parameters
Resist: 1.5 µm AZ 5214E
Substrate: 100 mm Si
O2: 100 sccm
N2: 100 sccm
Pressure (DSC): 1.3 mbar
Power: 1000 W
Time (single wafer): 20 minutes
Time (full boat): 90 minutes
Plasma asher 5 can be used for almost every material, but if you have any doubt if your materials are compatible/allowed in plasma asher 5, feel free to ask the lithography group at Nanolab.
The user manual, risk assessment, and contact information can be found in LabManager - requires login
