Supply control system for semiconductor process gasses

A supply control system for special gasses, comprising:

• a plurality of electromagnetic valves which may be placed in one of an open state and a closed state by means of control signals whereby said valves selectively enable an operating gas to flow;
• a plurality of drive units, said drive units operatively associated with an operating gas, and responsive to one of an open state and a closed state of said electromagnetic valves, said drive units respectively associated with said plurality of gas pressure operated valves;
• a plurality of gas pressure operated valves which are placed in one of an open state and a closed state by said drive units to thereby selectively enable a special gas to flow;
• a plurality of gas tubes interconnecting respective said electromagnetic valves with respective said drive units, said gas tubes conveying operating gas to said drive units;
• a process unit, said process unit connected to a plurality of connecting pipes, said plurality of connecting pipes respectively connected to said plurality of gas pressure operated valves;
• said plurality of gas tubes having respective volumes which are determined as a function of the length of time which elapses between the application of a control signal to said electromagnetic valve and the time when said special gas is supplied to said process unit.