Chemical mix and delivery systems and methods thereof
First Claim
1. A chemical delivery system, comprising:
- a main reservoir in fluid communication with one or more inlet fill valves, an inlet pressure valve, and a main reservoir outlet valve;
a buffer reservoir in fluid communication with a buffer reservoir inlet valve and a buffer outlet valve;
a line connecting the main reservoir outlet valve to the buffer reservoir inlet valve;
a load cell for monitoring the weight of a chemical in the buffer reservoir and generating analog signals that are converted to digital signals indicative of the weight of the chemical in the buffer reservoir;
a proportional valve block including a buffer control inlet valve and a buffer control outlet valve that adjusts the pressure to the buffer reservoir;
a programmable logic controller receiving the digital signals and generating control signals to the proportional valve block to achieve a desired chemical flow rate.
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Abstract
The present invention relates to chemical delivery systems and methods for delivery of liquid chemicals. In one embodiment, the present invention relates to systems having multi-reservoir load cell assemblies for delivering chemicals used in the semiconductor industry. In one embodiment, the present invention provides a multi-reservoir load cell assembly, including a controller, a buffer reservoir, a main reservoir, one or more load cells, coupled to the assembly and to the controller, operable to weigh the liquid in the reservoir(s), a plurality of supply lines, each supply line having a valve and connecting one of the supply containers to the main reservoir, and a gas and vacuum sources for withdrawing the liquid from the assembly when demanded by the controller and for refilling the assembly from the supply containers.
84 Citations
11 Claims
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1. A chemical delivery system, comprising:
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a main reservoir in fluid communication with one or more inlet fill valves, an inlet pressure valve, and a main reservoir outlet valve; a buffer reservoir in fluid communication with a buffer reservoir inlet valve and a buffer outlet valve; a line connecting the main reservoir outlet valve to the buffer reservoir inlet valve; a load cell for monitoring the weight of a chemical in the buffer reservoir and generating analog signals that are converted to digital signals indicative of the weight of the chemical in the buffer reservoir; a proportional valve block including a buffer control inlet valve and a buffer control outlet valve that adjusts the pressure to the buffer reservoir; a programmable logic controller receiving the digital signals and generating control signals to the proportional valve block to achieve a desired chemical flow rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of liquid chemical delivery at low flow rates in a system comprising a multi-reservoir load cell assembly, including a main reservoir, a buffer reservoir, each reservoir having at least one load cell and a mixer, and a logic device, comprising:
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isolating the main reservoir from the buffer reservoir; reducing pressure in the main reservoir; adding liquid chemical components sequentially into the main reservoir; weighing each liquid chemical component by the multi-reservoir load cell assembly; mixing the chemical components into a mixture; supplying the main reservoir with an inert gas; transporting mixture from the main reservoir to the buffer reservoir; and transporting the mixture from the buffer reservoir through a pinch valve.
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Specification