Higher Cost Pressure and More Rigid Specifications
In the Microelectronic world pressure variations in UPW, DI-Water and Chemical supply lines can be a problem for tools and processes. More and more, sophisticated manufacturing require a highly constant inlet pressure in order to keep the sensitive internal tool operations within the expected process window. As a result, any pressure fluctuations could possibly reduce process yields.
Based on continuously increasing cost pressure however, media supply systems are often designed at their limits. Further tool expansions often lead to unstable water supply situation. As a result, uncontrolled pressure fluctuations could cause extended cycle time, process interruptions, or even tool shut-downs. Major cost impacts are the consequence.
Severe Problems in Manufacturing FABS
In order to cope with these challenges, Microelectronic Manufacturers either face substantial investments in additional water treatment infrastructure or try to optimize the existing installed system.
Unfortunately only passive components such as pressure regulating valves are normally used which often results in a temporary unstable water pressure condition along with high particle contamination levels.
How can the Problem be solved?
Other than with passive elements an actively controlled system not only increases pressure actively but also is able to compensate fluctuations in water consumption.
As a result, a very accurate and constant pressure is provided, independent from water supply pressure and water consumption by the process tools.
A pressure transducer monitors the current tool incoming pressure and transmits the actual value to the pump controller. Based on the required set pressure, the magnetically levitated and electronically controlled pump dynamically increases the water pressure to the given set point.
By doing so, this closed loop pressure control design not only compensates supply pressure fluctuations, but also pressure variations caused by individual water consumption of the process tools in line.