Chemical delivery systems and methods of delivery
First Claim
1. A liquid chemical delivery system for use with a plurality of supply containers, comprising:
- a controller;
a multi-reservoir load cell assembly, including, a buffer reservoir with a chemical output, a main reservoir, a reservoir valve connecting the buffer reservoir to the main reservoir, and a load cell, coupled to the assembly and to the controller, operable to weigh the liquid in the reservoir assembly;
a plurality of supply lines, each having a valve coupled to the controller and to one of the supply containers to the main reservoir; and
means for withdrawing the liquid from the chemical output, opening and closing the reservoir valve, and refilling the main reservoir from the supply containers when demanded by the controller based on signals from the load cell.
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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.
86 Citations
17 Claims
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1. A liquid chemical delivery system for use with a plurality of supply containers, comprising:
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a controller; a multi-reservoir load cell assembly, including, a buffer reservoir with a chemical output, a main reservoir, a reservoir valve connecting the buffer reservoir to the main reservoir, and a load cell, coupled to the assembly and to the controller, operable to weigh the liquid in the reservoir assembly; a plurality of supply lines, each having a valve coupled to the controller and to one of the supply containers to the main reservoir; and means for withdrawing the liquid from the chemical output, opening and closing the reservoir valve, and refilling the main reservoir from the supply containers when demanded by the controller based on signals from the load cell. - View Dependent Claims (2, 3)
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4. A chemical delivery system, comprising:
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a multi-reservoir load cell assembly comprising a main reservoir capable of fluid communication with a buffer reservoir and a first load cell weighing the assembly and generating an output signal indicative of the weight; and means, responsive to the output signal, for adjusting the pressure in the main reservoir and in the buffer reservoir, for calculating the amount of chemical in the assembly, and for controlling fluid communication between the main reservoir from the buffer reservoir. - View Dependent Claims (5, 6, 7, 8, 9)
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10. A liquid chemical delivery system, comprising:
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a multi-reservoir load cell assembly, including a main reservoir with a gas inlet, a liquid inlet, and a liquid outlet, and a buffer reservoir with a gas inlet and a liquid inlet; at least one load cell to weigh the chemical contained in the assembly and generate an output signal indicative of the weight; a first valve and a second valve associated with the main reservoir liquid inlet; a third valve connecting the main reservoir liquid outlet and the buffer reservoir liquid inlet; a fourth valve connecting the main reservoir gas inlet and the buffer reservoir gas inlet; means, responsive to the output signal, for refilling the buffer reservoir with chemical when the output signal indicates chemical in the buffer reservoir has dropped to a predetermined level, comprising; closing the third valve to isolate the main reservoir from the buffer reservoir, opening the fourth valve to evacuate the main reservoir to draw liquid chemical into the main reservoir until the liquid chemical rises to a predetermined level, opening the valve between the main reservoir and the buffer reservoir to allow the liquid chemical in the main reservoir to flow into the buffer reservoir.
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11. A liquid chemical delivery system coupled to one or more supply containers, comprising:
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a multi-reservoir load cell assembly, including a main reservoir, a buffer reservoir, and at least one load cell; a logic device coupled to the load cell(s) providing output signals to actuate; means for sealing and unsealing the buffer reservoir from the main reservoir, a vacuum generator for evacuating the main reservoir to draw liquid chemical from the supply container(s) to the main reservoir; and a gas source supplying the main reservoir to blanket the liquid chemical in the main reservoir. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A liquid chemical delivery system adapted for one or more supply containers, comprising:
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a multi-reservoir load cell assembly, including a main reservoir, a buffer reservoir, and at least one load cell; a logic device coupled to the load cell(s) providing output signals to actuate; means for sealing and unsealing the buffer reservoir from the main reservoir, a vacuum generator communicating with the main reservoir for evacuating the main reservoir to draw liquid chemical from the supply container(s) into the main reservoir; and a gas source communicating with the main reservoir to blanket the liquid chemical in the main reservoir.
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Specification