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=Plasma Asher 1=
= Descum Comparison Table =
<span style="color:red">Plasma asher 1 was decommissioned 2024-12-02.</span>
[[Specific Process Knowledge/Lithography/Descum/PlasmaAsher1|Information about decommissioned tool can be found here.]]
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=Plasma Asher 2=
<span style="color:red">Plasma asher 2 was decommissioned 2024-12-02.</span>
[[Specific Process Knowledge/Lithography/Descum/PlasmaAsher2|Information about decommissioned tool can be found here.]]
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=Plasma Asher 3: Descum=
Product name: Diener Pico Plasma Asher<br>
Year of purchase: 2014
The user manual(s), quality control procedure(s) and results and contact information can be found in [http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=423 LabManager] - '''requires login'''
Plasma Asher 3 is specifically used for controlled descum process after lithography. Please note that you only can process a single 100 mm wafer, or one small sample, at a time.
The plasma asher is equipped with 2 gaslines: oxygen and nitrogen, but all standard processes use only oxygen (as recommended by Diener).
'''Process parameters'''<br>
You can manipulate two different descum process development parameters: you can either change power or chamber pressure.
==Power testing - AZ MiR 701==
[[image:AZMIR701_power_settings.png|400px|thumb|Descum results for different power settings]]
Descum of AZ 5214E on 100 mm wafers. The descum process development was done for a single substrate, as well as 3 substrates (for decreased ashing rate and improved ashing uniformity). The substrates were placed vertically in the glass boat.
PA_boat_3Wafer_v2.png|3 vertical substrates:<br>Dummy - Test - Dummy
</gallery>
For the 3 substrates only the center substrate was used for testing, the front and back wafers were used as dummy wafers. The wafers were placed in consecutive slots - when running multiple wafers in this way, the first and last wafers should always be dummy wafers.
The user manual, risk assessment, and contact information can be found in [http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=530 LabManager] - '''requires login'''
'''Typical descum parameters'''<br>
Tested with 1.5 µm AZ 5214E on 100 mm silicon substrate.
*O<sub>2</sub>: 100 sccm
*N<sub>2</sub>: 100 sccm
*Pressure (DSC): 1.3 mbar
*Power: 200 W
*Chamber temperature at start (with door closed): 30°C
<span style="color:red">Plasma asher 1 was decommissioned 2024-12-02.</span>
==Multi wafer descum ashing rate and uniformity for plasma asher 4 & 5==
[[Specific Process Knowledge/Lithography/Descum/PlasmaAsher1|Information about decommissioned tool can be found here.]]
[[File:PA_descum_multi_v3.png|400px|thumb|Ashing amount and ashing rate when processing multiple 100 mm wafers. Test measured on the center of 3 wafers.|right]]
{| class="wikitable" style="text-align: center;"
|+ style="caption-side: top; text-align: left;" | Ashing amount and rate
==Comparison between single substrate processing and multi substrate processing for plasma asher 4 & 5==
Processing a single substrate using the standard descum settings will provide users with a relatively controllable and uniform process. Adding dummy substrates in close proximity with the process substrate will reduce the ashing rate and improve the uniformity:
<gallery mode="packed-hover" heights="150">
PA_descum_compareAmount_v1.png|Ashing amount
PA_descum_compareRate_v1.png|Ashing rate
PA_descum_compareUniformity_v1.png|Non-uniformity
</gallery>
[[Specific Process Knowledge/Lithography/Descum/PlasmaAsher2|Information about decommissioned tool can be found here.]]
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==Comparison of ashing rate between substrate sizes==
Plasma asher 5 is identical to plasma asher 4, see descum processing for plasma asher 4 [[Specific_Process_Knowledge/Lithography/Descum#Plasma_Asher_4|here]].
Latest revision as of 12:31, 13 January 2026
The content on this page, including all images and pictures, was created by DTU Nanolab staff, unless otherwise stated.
Films, or patterned films, of any material except type IV (Pb, Te)
No metals
No metal oxides
No III-V materials
Silicon substrates
Glass substrates
Polymer substrates
Films, or patterned films, of resists/polymers
Silicon substrates
III-V substrates
Glass substrates
Polymer substrates
Films, or patterned films, of any material except type IV (Pb, Te)
Plasma Asher 3: Descum
Product name: Diener Pico Plasma Asher
Year of purchase: 2014
The user manual(s), quality control procedure(s) and results and contact information can be found in LabManager - requires login
Plasma Asher 3 is specifically used for controlled descum process after lithography. Please note that you only can process a single 100 mm wafer, or one small sample, at a time.
The plasma asher is equipped with 2 gaslines: oxygen and nitrogen, but all standard processes use only oxygen (as recommended by Diener).
Process parameters
You can manipulate two different descum process development parameters: you can either change power or chamber pressure.
Power testing - AZ MiR 701
Descum results for different power settings
Recipe settings:
Resist: AZ MiR 701
O2 flow: 5 sccm
N2 flow: 0
Pressure: 0.2 mbar
Power: Varied
Experiment parameters
Forward/reverse
C2/C1
Power
recipe 1
50/0
52/31
50%
recipe 2
100/0
53/31
100%
recipe 3
20/0
51/34
20%
Pressure testing - AZ MiR 701
Descum results for different pressure settings
Recipe settings:
Resist: AZ MiR 701
O2 flow: varied
N2 flow: 0
Pressure: varied
Power: V100% (100 W)
Experiment parameters
Forward/reverse
C2/C1
Oxygen
Pressure
recipe 1
100/0
52/31
5
0.2
recipe 2
100/0
37/38
45
0.8
Pressure testing - AZ 5214E
Descum results for different pressure settings
Recipe settings:
Resist: AZ 5214E
O2 flow: varied
N2 flow: 0
Pressure: varied
Power: V100% (100 W)
Experiment parameters
Forward/reverse
C2/C1
Oxygen
Pressure
recipe 1
100/0
52/31
17
0.4
recipe 2
100/0
37/39
45
0.8
Plasma Asher 4
Product name: PVA Tepla Gigabatch 380M
Year of purchase: 2024
Descum of AZ 5214E on 100 mm wafers. The descum process development was done for a single substrate, as well as 3 substrates (for decreased ashing rate and improved ashing uniformity). The substrates were placed vertically in the glass boat.
Single vertical substrate
3 vertical substrates: Dummy - Test - Dummy
For the 3 substrates only the center substrate was used for testing, the front and back wafers were used as dummy wafers. The wafers were placed in consecutive slots - when running multiple wafers in this way, the first and last wafers should always be dummy wafers.
The user manual, risk assessment, and contact information can be found in LabManager - requires login
Typical descum parameters
Tested with 1.5 µm AZ 5214E on 100 mm silicon substrate.
O2: 100 sccm
N2: 100 sccm
Pressure (DSC): 1.3 mbar
Power: 200 W
Chamber temperature at start (with door closed): 30°C
Time (single wafer): 5-10 minutes = 35-72 nm ashed
Time (multiple wafers): 10-15 minutes = 40-80 nm ashed
Single substrate
Center of 3 substrates
Test results: ashing rate
5.7 ±2.1 nm/min
3.8 ±1.6 nm/min
Test results: non-uniformity
0.6 ±0.4%
0.4 ±0.2%
Wafers
1
3
Wafer size
100 mm
100 mm
Boat position
Center of chamber
Center of chamber
Test wafer position
Center of boat
Center of boat
Total gas flow rate
200 sccm
200 sccm
Gas mix ratio
50% N2
50% N2
Chamber pressure
1.3 mbar
1.3 mbar
Power
200 W
200 W
Test processing time
Tested parameter
Tested parameter
Test average temperature
33°C
33°C
Single wafer descum ashing rate and uniformity for plasma asher 4 & 5
Ashing amount and ashing rate when processing a single 100 mm wafer.
Ashing amount and rate
Ashing time [min]:
1
2
5
10
15
Ashing amount [nm]:
5.2
6.2
35.1
72.3
87.1
Ashing rate [nm/min]:
5.2
3.1
7.0
7.2
5.8
Ashing non-uniformity
Ashing time [min]:
1
2
5
10
15
Pre-descum film thickness range [nm]:
11
12
10
11
9
Pre-descum non-uniformity [%]:
0.37
0.40
0.33
0.37
0.30
Post-descum film thickness range [nm]:
10
10
12
19
33
Post-descum non-uniformity [%]:
0.33
0.33
0.41
0.66
1.18
Multi wafer descum ashing rate and uniformity for plasma asher 4 & 5
Ashing amount and ashing rate when processing multiple 100 mm wafers. Test measured on the center of 3 wafers.
Ashing amount and rate
Ashing time [min]:
1
2
5
10
15
Ashing amount [nm]:
4.3
6.7
10.1
39.5
78.8
Ashing rate [nm/min]:
4.3
3.4
2.0
4.0
5.3
Ashing non-uniformity
Ashing time [min]:
1
2
5
10
15
Pre-descum film thickness range [nm]:
11
13
11
12
14
Pre-descum non-uniformity [%]:
0.37
0.43
0.37
0.40
0.46
Post-descum film thickness range [nm]:
11
9
10
12
21
Post-descum non-uniformity [%]:
0.37
0.30
0.33
0.41
0.74
Comparison between single substrate processing and multi substrate processing for plasma asher 4 & 5
Processing a single substrate using the standard descum settings will provide users with a relatively controllable and uniform process. Adding dummy substrates in close proximity with the process substrate will reduce the ashing rate and improve the uniformity:
Ashing amount
Ashing rate
Non-uniformity
Comparison of ashing rate between substrate sizes
It is assumed that the low power descum rates, for different substrate sizes, follows the same pattern as the high power ashing rates, which can be seen here.
Plasma Asher 5
Product name: PVA Tepla Gigabatch 380M
Year of purchase: 2024
Plasma asher 5 is identical to plasma asher 4, see descum processing for plasma asher 4 here.
Single vertical substrate
3 vertical substrates:
Ashing amount
Ashing rate
Non-uniformity
