FOUPs provide an enclosed environment for transporting and storing wafers between process steps. N₂ purging helps maintain the required protective atmosphere inside the FOUP and limits exposure to atmospheric oxygen and airborne contamination.
The challenge is not simply to reduce the nitrogen flow. The flow needs to match the requirements of the purge process while avoiding unnecessary consumption.
Precisely controlling the flow and pressure of nitrogen is therefore essential to make sure the supply can react reliably to changing process conditions.
Piezoelectric benders convert electrical voltage into precise mechanical movement. This allows the pressure or flow to be regulated continuously and precisely while requiring very little electrical power.
The proportional-pressure regulator VEAD and mass flow controller VEFC use this principle to control inert gases such as nitrogen. Thanks to their precise regulation, fast response and low particle generation they are suitable for sensitive semiconductor applications.
A constant or high flow rate often supplies more nitrogen than is really needed. Piezo-based control adjusts the N₂ flow more precisely to what is actually required in the process.
In a Festo sample calculation, a regulated flow reduced the purge rate from 20 to 5 SLPM per FOUP, corresponding to a reduction of up to 75%. Actual savings depend on process requirements and operating conditions.
Piezo-based pressure or flow control can be particularly useful when the application requires:
OUP purging is part of a wider semiconductor production environment. The relevant automation requirements depend on the equipment and process area.
For applications involving deposition, etching, ion implantation, and related wafer-processing equipment, explore high-vacuum processes in semiconductor production.
For FOUP purging and other N₂ purge applications in atmospheric process environments, explore atmospheric processes in semiconductor production.