a system using backside helium in the processing of wafers in the manufacturing of semiconductor products can cause alarms that can interrupt the manufacturing of the wafers and create damaged wafers . a pid controller responds to the flow of helium gas to generate control signals for operating several algorithms . a filter connected to the output of the pid controller removes unwanted and dangerous noise spikes that have in the past caused a condition called backside alarm . noise spikes on the dc voltages , the helium supply pressure , the pressure set point , the pressure reading and the non - optimization of the pid controller can cause the alarm .