Custom clean room temperature control for lithography tool - Case Study
The Challenge: Air Innovations partnered with a semiconductor tool firm to design and build an environmental control unit with once-thru steady-state air to maintain conditions within a semiconductor lithography tool. Inlet air was to be taken from the existing class 1000 controlled environment. The unit needed to conform to a precise footprint: 26” x 30”. The clean room temperature was to be maintained at 68°F – 74°F ±0.36°F (±0.2°C). Furthermore, the lithography tool could not experience more than 2°F change in any 1-hour period. This semiconductor customer also requested the unit feature a water-cooled condenser with leak detection and solenoid valves for system shutoff in case of a water leak.
To ensure clean room temperature control accuracy, Air Innovations designed the water-cooled semiconductor HVAC system to include a temperature sensor with an accuracy of ±0.1°F. The final unit also features hot-gas bypass refrigeration control.
This custom environmental control system included a 5kW electric reheater to maintain very limited temperature change in any given hour and in case expected ambient conditions dipped below normal.
The final stainless steel environmental control system for the lithography tool included Poron® microcellular closed-cell insulation, urethane sealants, and closed-cell gaskets. As with all AdvancAir® systems, this unit was also designed to meet SEMI standards, and included non-shedding, non-off-gassing componentry, and a DIP inverter to protect against power drops.
- All design specifications were met within the 11-12 week lead time (future units would be delivered in 8 weeks).
- The environmental control system included cooling, heating, dehumidification, pre-filtration, and HEPA filtration
- Design output conditions of 68°F -74°F ±0.36°F (±0.2°C) were met.
- 2500 – 4000 CFM variable operational range
- 5” external static pressure
- Separate auto-tuning PID loop controllers for temperature
- Water-cooled condenser with leak detection and hot-gas bypass refrigeration control
- The temperature control system can take 3 different voltage inputs: 380-415V/3/50, 200-220V/3/50, or 208-230V/3/60 ±10%
- Meets all SEMI and UL certification requirements