Liquid delivery system

A liquid delivery system, comprising:

• a first liquid delivery module adapted to store and dispense a first chemical;
• a second liquid delivery module adapted to store and dispense a second chemical;
• and
• at least one connecting mechanism coupled to the first and second delivery modules and adapted to couple the first and second delivery modules to a substrate processing device;
• wherein each of the liquid delivery modules includes:
• a vessel including a first chamber and a second chamber, the first chamber including a first port and a second port, the vessel configured to receive a liquid from a bulk supply and to receive a pressurized flow of gas from a gas source, the second chamber configured to be in fluid communication with the substrate processing device through a first port and with a pressurized gas supply through a second port;
• and
• a valve assembly operable to selectively permit fluid communication between the first chamber and the second chamber during a non-refill state and to prevent fluid communication between the first chamber and the second chamber during a refill state, the valve assembly including,
• a first control valve positioned between the first port of the first chamber and the first port of the second chamber,
• a second control valve positioned between the second port of the first chamber and the second port of the second chamber,
• a material supply valve positioned between the first port of the first chamber and a bulk supply,
• a vent valve positioned between the second port of the first chamber and an outside environment;
• such that in the non-refill state the first and second control valves are open, the material supply valve is closed, and the vent valve is closed, and in the refill state the first and second control valves are closed, the material supply valve is open, and the vent valve is open.