Safety Aspects And Considerations For Vacuum And Exhaust Management Of Hazardous And Energetic Materials Within Polysilicon Processes
Steve Cottle
Polysilicon furnace processes can use several silicon-bearing gases, including silane, disilane and DIPAS. Chamber cleans use either fluorine or chlorine trifluoride. Process steps may take several hours and rightly demand high reliability from downstream support systems; vacuum, abatement, facilities equipment. In addition to reliability, fab operators must address environmental and safety compliance from gas pad to end-of-pipe release. We have drawn up a simple process flow diagram to describe the fab. Chris Jones will discuss the environmental impacts of this scheme in a separate presentation.
In this paper, we will examine the safety implications starting from first principles of process hazard analysis. We will delve into hazards posed by each of the gases (flammability, toxicity, corrosiveness, etc.) and look at the potential hazards relating to energetic materials (SEMI S30). Then discuss how vacuum and exhaust management can be used and assessed to mitigate these risks in best operational practices.