Specific Process Knowledge/Wafer and sample drying

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Unless anything else is stated, everything on this page, text and pictures are made by DTU Nanolab.

Drying Comparison Table

Equipment	Spin dryer 2	Spin dryer 3	Spin dryer 4	Spin dryer 5	Critical point dryer	Ethanol fume dryer	N2 guns
Location	B-1	D-3	D-3	F-3	D-3	C-1	In fumehoods and at chemical benches
Purpose	Drying	Drying	Drying	Drying Rinsing + drying	Drying sensitive samples. E.g. with cantilevers	Drying sensitive samples. E.g. with cantilevers	Drying all kind of samples.
Batch size	1-25 100 mm wafers 1-25 150 mm wafers	1-25 100 mm wafers 1-25 150 mm wafers	1-25 100 mm wafers 1-25 150 mm wafers	1-25 100 mm wafers 1-25 150 mm wafers 1-25 200 mm wafers	1 to 5 wafers per run. Sizes: 2”, 4" or 6" Pieces (up to 10x10mm)	1-25 50 mm wafers 1-25 100 mm wafers Pieces if a suitable carrier is available	One sample at a time
Allowed materials	Only for RCA cleaned wafers	No restrictions	No restrictions	No restrictions	Si,SiO2, Si3N4 Quartz and Pyrex InAlP, GaAs SU8	No restriction except for polymers	No restriction

Spin dryers

A tool used for drying wafers. A single cassette of wafers is placed in a stainless steel rotor. The wafers are centered just off the axis of rotation, and rotated at high RPM so that centrifugal force “locks” the wafers in place.

Some of the tools have DI water connected, and can be used for both rinsing and drying of wafers, while other tools do not and can only be used for drying. All wafers have to be washed in a wetbench cleaning station before going into the spin dryer, regardless of using the rinse function or not.

The user manual, technical information, and contact information can be found in LabManager: Spin dryer 2 Spin dryer 3

Process information

Standard process is:

1. Rinse (with DI water) for 60 seconds at 500 RPM
2. Dry with nitrogen for 150 seconds at 1800 RPM
3. Dry with nitrogen and anti-static purge for 30 seconds at 1800 RPM

• Different places to dry your wafers
• 
  Spin dryer 2 for RCA cleaned wafers only in B-1. Can take 4" wafers (top) and 6" wafers (bottom).
• 
  Spin dryer 3 for 4" wafers (top) and 6" wafers (bottom) in D-3.
• 
  Spin dryer 5 for 8", 6" and 4" wafers in the same chamber, with different carrier holders.

Ethanol fume dryer

If your wafers are fragile or having thin membranes, cantilevers or suspended bridges that risk to stick or adhere to the surface it can be a good idea to dry your wafers in the ethanol fume dryer. Ethanol is heated to 70°C and your wafers are placed in the fumes of Ethanol which will make the water evaporate from the surface. The Ethanol dryer is placed on a shelf or trolly in D-3 and looks like a US bath. Describtion on how to use is written on the bath.

Nitrogen guns

Nitrogen guns are valuable for drying small substrate pieces or samples that otherwise cannot go into the outer drying tools.