Knowledge Base - Spin Rinse Dryer - Wafer Cleaning
What is a Spin Rinse Dryer?
The job of a spin rinse dryer is to rinse and dry batches of wafers in a cassette. The wafers are usually loaded into a stainless steel drum or chamber then rotated while injecting DI (de-ionised water) to rinse off any particle that might be left over from a previous process step such as etching.
Drying of the wafers usually is by rotating the wafers at around 10,000 rpm while injecting heated nitrogen in to the bowl. Static electricity can build up while drying which could help particles adhere to the surface or even damage some delicate devices, this can be reduced by static eliminator assemblies.
What bowl size?
Normally wafer cassettes fit into a stainless steel rotor that has been balanced to spin smoothly during the speed ramping and maximum velocity stages of any recipe. Bowl size is the easiest option to discuss as bowls can normally handle several different wafer sizes with a rotor change or a liner that fits into an oversized rotor.
Non Standard Wafers
Wafers can be thin, fragile and brittle so the machines need processes defined to accommodate any variations.
Wafers are normally spun inside a dedicated cassette and the rotors that hold the cassette are balanced to account for any weight variance. Rotors are key to stop any unwanted vibrations that could cause damage to wafers or the tool. Should only partial loads be run in the tool then consideration should be given to weight distribution. Many different items can be rinsed in the SRD and can vary from standard wafers. Common practice includes:
- Wafer Standard 2"- 12"
- Glass Mask plates
- Diced Wafers
- Broken or wafer sections (on dicing tape and frames)
Defining an SRD
The best way to start is by trying to decide what range of materials you require processing and how often the tool will be run.
Support your old SRDs Semitool & Verteq
We have support and upgrade options to many old and legacy tools. From controller repairs to N2 Saving kits to power supplies and rotary seal replacements.
