Study of Emergency Leakage from Gas Cabinets using Controlled Flows of Arsine
(CS CLEAN SOLUTIONS AG)
Arsine (AsH3) is a very lethal form of arsenic and in most jurisdictions is subject to the most stringent safety and reporting regulations applicable to the transport, storage and usage of gases. Among the many hazardous gases commonly used in the manufacture of semiconductor chips, arsine poses the greatest threat in terms of toxicity. Up until a few years ago, the use of arsine within the silicon semiconductor industry was confined to ion implantation and doped epitaxy applications, where the gas is supplied to the process in relatively low, dopant, quantities, often from safe delivery sources. In recent years gallium arsenide (GaAs) and related compound semiconductor materials have found their way into an increasing number of silicon semiconductor facilities. With the trend towards higher arsine throughput set to continue, the safe storage of AsH3 cylinders and measures to contain emergency leakages from gas cabinets are likely to become even more challenging in the coming years. This presentation will report on testing carried out by CS CLEAN SOLUTIONS in a specially-constructed outdoor facility to verify the gas retention performance of a dry bed emergency containment system. To our knowledge, this is the first time that a simulated release of AsH3 has been conducted using controlled flows of the pure gas at flowrates comparable to those to be expected during a real-life leakage situation. Topics presented will include design of experiment, parameter monitoring, a discussion of results and a summary of lessons learned.