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US 5,711,354 AGranted
Level control systems for high purity chemical delivery systems
AssigneeAdvanced Delivery & Chemical Systems, Ltd.
InventorsStephen H. Siegele, Craig M. Noah, John N. Gregg
Life of this patent
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Abstract
A highly reliable digital level sensor assembly is provided to replace optical and capacitance type sensors in high purity chemical delivery systems. The digital level sensor assembly is particularly useful in bulk chemical refill delivery systems for high purity chemicals employing a manifold that ensures contamination free operation and canister change outs with a minimum of valves and tubing.
Claims12
A level control system comprising a refillable ampule;
- a bulk container containing a high purity source chemical;
- a refill line interposed between and communicating with said ampule and said bulk container for transferring the high purity source chemical from said bulk container to said ampule;
- a first metallic float level sensor inside said ampule having at least one trigger point for detecting a first level of the high purity source chemical and comprising a first magnetic sensor, said first magnetic sensor comprising a normally open terminal, a normally closed terminal and a common terminal;
- and
- an interface circuit for interfacing said metallic float level sensor with a CVD reactor, said CVD reactor having an indicator that provides a signal to indicate that the high purity source chemical in said ampule is at said first level when the level of the high purity source chemical in said ampule reaches the trigger point of said metallic float sensor
- said interface circuit comprising a first resistor connected to the output of said normally closed terminal of said first magnetic sensor, a voltage supply connected to said common terminal of said first magnetic sensor, and said first resistor and said normally open terminal of said first magnetic sensor tied together and communicated to said CVD reactor.
3 more elements
A level control system comprising a refillable ampule;
- a bulk container for containing a high purity source chemical;
- a refill line interposed between and communicating with said ampule and said bulk container for transferring the high purity source chemical from said bulk container to said ampule;
- a first metallic float level sensor inside said ampule having at least one trigger point for detecting a first level of the high purity source chemical;
- an interface circuit for interfacing said metallic float level sensor with a CVD reactor, said CVD reactor having an indicator that provides a signal to indicate that the high purity source chemical in said ampule is at said first level when the level of the high purity source chemical in said ampule reaches the trigger point of said metallic float sensor;
- and,
- a manifold comprising a carrier gas line for providing inert gas from an inert gas pressure source to said bulk container;
- means disposed in said refill line for isolating the outlet of said bulk container from a portion of said refill line;
- means in said carrier gas line for isolating maid inert gas pressure source from the inlet of said bulk container;
- means for connecting a vacuum source to said carrier gas line;
- and means for bypassing said inert gas pressure source and the vacuum source to at least a portion of said refill line that was not isolated by said means for isolating said refill line.
7 more elements
A level control system comprising a refillable ampule;
- a bulk container for containing a high purity source chemical;
- a refill line interposed between and communicating with said ampule and said bulk container for transferring the high purity source chemical from said bulk container to said ampule;
- a first metallic float level sensor inside said ampule having at least one trigger point for detecting a first level of the high purity source chemical;
- an interface circuit for interfacing said metallic float level sensor with a CVD reactor, said CVD reactor having an indicator that provides a signal to indicate that the high purity source chemical in said ampule is at said first level when the level of the high purity source chemical in said ampule reaches the trigger point of said metallic float sensor;
- and,
- a manifold comprising a process line isolation valve interposed in said refill line for isolating said bulk container from a portion of said refill line;
- a carrier gas isolation valve for isolating said bulk container from an inert gas pressure source;
- a low pressure vent valve for isolating a vacuum source from said carrier gas line;
- and a canister bypass valve for bypassing said pressure source and the vacuum source to at least a portion of said refill line that was not isolated by said process isolation valve.
6 more elements
Dependencies are inferred from the claim text.