K850WM Large Chamber Critical Point Dryer
The K850WM is a compact, bench-top instrument designed to critical point dry a complete 150 mm wafer. A convenient wafer holder allows rapid transfer and ensures that pre-drying does not occur.
The K850WM has built-in heating and water cooling using the E4860 Recirculating Heater/Chiller. This combination will give temperature control of +5°C cooling and +35°C during heating. This ensures the critical point is accurately obtained and avoids excess pressures and temperatures or the need to rely on pressure relief valves to control pressure during the heating cycle.
The K850WM has a vertical chamber which allows top-loading of the specimen. A viewing port in the top plate allows observation of the chamber and wafer during the critical point drying process.
The exchange mechanism is simple to use and ensures the specimen remains under liquid during loading.
Specimen handling
100 mm or 150 mm diameter wafers are held in a PTFE holding tray. The tray including wafer is immersed in acetone in order to remove all moisture from the specimen. After dehydration, the wafer and holder are transferred into the pre-cooled specimen chamber using the wafer transfer device. On completion of the critical point drying process, the wafer is removed from the chamber using the transfer device prior to further processing.
Key features
- 170 mm diameter chamber - optimised for wafer/MEMS drying
- Vertical chamber with top-loading and bottom draining - ensures specimens do not become uncovered during drying
- Thermoelectric heating - accurate temperature control
- Fine control needle valve pressure let down - precise control
- Temperature monitoring and control with thermal cut-out protection
- Pressure monitoring with safety cut-out for over pressure