Specific Process Knowledge/Lithography/Strip

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Strip Comparison Table

Equipment		Plasma Asher 3: Descum	Plasma Asher 4	Plasma Asher 5	Resist strip	Lift-off
Purpose		Resist descum	Clean wafers only, no metal	All purposes	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	O2 (flow unknown)	O2 (0-500 sccm) N2 (0-500 sccm)	O2 (0-500 sccm) N2 (0-500 sccm) CF4 (0-200 sccm)	NA	NA
	Max. process power	100 W (100%)	150-1000 W	150-1000 W	NA	NA
	Solvent	NA	NA	NA	NMP (Remover 1165) Rinse in IPA	NMP (Remover 1165) Rinse in IPA
Substrates	Batch size	1 small sample 1 50 mm wafer 1 100 mm wafer	1 small sample 1 50 mm wafer 1-25 100 mm wafers 1-25 150 mm wafers 1-25 200 mm wafers	1 small sample 1 50 mm wafer 1-25 100 mm wafers 1-25 150 mm wafers 1-25 200 mm wafers	1 - 25 100 mm wafers 1 - 25 150 mm wafers	1 - 25 100 mm wafers 1 - 25 150 mm wafers
	Allowed materials	Silicon, glass, and polymer substrates Film or pattern of all but Type IV	No metals allowed! This includes metal oxides Silicon, glass, and polymer substrates Film or pattern of photoresist/polymer	Silicon, III-V, and glass substrates Film or pattern of all but Type IV	No metal allowed! Silicon, glass, and polymer substrates Film or pattern of photoresist/polymer	Silicon and glass substrates Film or pattern of all but Type IV

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	O2 (400 sccm) N2 (0-70 sccm)	O2 (70-210 sccm) N2 (0-70 sccm)	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.

Plasma Asher 2

Plasma asher 2 was decommissioned 2024-12-02.

Plasma Asher 3: Descum

Plasma Asher 3: Descum is placed A-5

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

• Descum

Plasma Asher 4

Coming soon

Plasma Asher 5

Coming soon

Resist Strip

Resist strip bench in D-3

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	100 mm wafers 150 mm wafers	100 mm wafers 150 mm wafers
Allowed materials	Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride	All metals except Type IV (Pb, Te)