Specific Process Knowledge/Lithography/Strip
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Strip Comparison Table
| Equipment | Plasma Asher 1 | Plasma Asher 2 | Plasma Asher 3: Descum | Resist strip | Lift-off | |
|---|---|---|---|---|---|---|
| Purpose |
All purposes |
Clean wafers only, no metal |
Resist descum |
Resist strip, no metal lift off |
Lift-off | |
| Method |
Plasma ashing |
Plasma ashing |
Plasma ashing |
Solvent and ultra sound |
Solvent and ultra sound | |
| Process parameters | Process gasses |
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| Max. process power |
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| Solvent |
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| Substrates | Batch size |
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| Allowed materials |
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No metal allowed!
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No metal allowed!
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Plasma Ashing
| Photoresist stripping | Descum after lithography | Surface treatment of plastic, ceramic and metal | Ashing of organic material | |
|---|---|---|---|---|
| Process pressure | 0.8- 1.2mbar | 0.5- 1.0mbar | 0.5- 1.0mbar | 0.8-1.5mbar |
| Process gases |
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O2, CF4, N2 or their mixtures | O2 |
| Process power | 600-1000W | 150-300W | 150-300W | 1000W or less for heat- sensitive materials |
| Process time | 5-60 minutes | 1-5 minutes | a few seconds to a few minutes | Between 0.5 and 20 hours, depending on the material |
| Batch size | 1-30 | 1-10 | 1 wafer at a time | 1 wafer at a time, use a container, e.g Petri dish |
Typical process time for stripping in plasma asher 1 or 2:
- 1.5 µm AZ 5214E resist film: ~15 min
- 10 µm AZ 4562 resist film: ~45 min
Typical process parameters:
- O2: 400 ml/min
- N2: 70 ml/min
- Power: 1000 W
A typical descum process in plasma asher 1 or 2:
- O2: 70 ml/min
- N2: 70 ml/min
- Power: 150 W
- Time : 10 min
Be sure to wait for chamber to cool down to room temperature, before runinng descum processes in plasma asher 1 or 2. At a load of 2 Fused silica wafers, the amount of resist removed will be 10 - 1500 nm.
NB: Use dedicated descum asher Plasma Asher 3: Descum for descumming.
Plasma Asher 1
Plasma asher 1 was decommissioned 2024-12-02.
Information about decommissioned tool
Plasma Asher 2
Plasma asher 2 was decommissioned 2024-12-02.
Information about decommissioned tool
Plasma Asher 3: Descum

The Plasma Asher 3: Descum dedicated for resist descum i.e. removal of remains resist traces after development. It has a small chamber, so you can only load one 4 inch substrate ad time or few smaller pieces.
In this machine, only O2 and N2 gases are used for processes.
The typical process parameters when operating the equipment:
- Photeresist descum
Pressure: 0.2 - 0.8mbar Gas: O2 Power: 50% - 100% Time: 1 -10 min., depending on photoresist type and thickness
The other materials have not been tested yet.
The user manual, user APV, and contact information can be found in LabManager - requires login
Process Information
Plasma Asher 4
Coming soon
Plasma Asher 5
Coming soon
Resist Strip

This resist strip is only for wafers without metal and SU-8.
There are one Remover 1165 bath for stripping and one IPA bath for rinsing.
Here are the main rules for resist strip use:
- Place the wafers in a wafer holder and put them in the first bath for 10 min, this time is depending how much resist you have on the surface.
- After the strip rinse your wafers in the IPA bath for 2-3 min.
- Rinse your wafers for 4-5 min. in running water after stripping.
The user manual and contact information can be found in LabManager: Resist Strip - requires login
Overview of wet bench 06 and 07
| Resist Strip | Lift-off | |
|---|---|---|
| General description | Wet stripping of resist | Lift-off process |
| Chemical solution | NMP Remover 1165 | NMP Remover 1165 |
| Process temperature | Up to 65°C | Up to 65°C |
| Batch size |
1 - 25 wafers |
1 - 25 wafers |
| Size of substrate |
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| Allowed materials |
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All metals except Type IV (Pb, Te) |