WO2009010970A2 - Modular chemical delivery unit - Google Patents

Abstract

A liquid chemical delivery system including a plurality of at least partially redundant pump modules, each including a programmable logic controller, a human-machine interface and a liquid pumping functionality and being operative to deliver a liquid chemical via a supply line to at least one point of use, a computer network interconnecting the plurality of at least partially redundant pump modules and software for coordinating the operation of the plurality of at least partially redundant pump modules.

Description

MODULAR CHEMICAL DELIVERY UNIT

CROSS REFERENCE TO RELATED APPLICATION^)

Reference is made to U.S. Provisional Patent Application Serial No. 60/959,842, filed July 16, 2007 and entitled MODULAR CHEMICAL DELIVERY UNIT, the disclosure of which is hereby incorporated by reference and priority of which is hereby claimed pursuant to 37 CFR 1.78(a) (4) and (5)(i).

FIELD OF THE INVENTION

The present invention relates to chemical delivery systems, particularly useful in semiconductor manufacturing facilities.

BACKGROUND OF THE INVENTION

The following documents are believed to represent the current state of the art:

U.S. Patent Nos. 6,834,777; 6,749,086; 6,561,381; 6,092,994; 5,950,693; 5,620,524; 5,359,787 and 5,115,842.

Published PCT applications: WO/2003/093118; WO/2003/088314; WO/2003/082729; WO/2000/039021 and WO/1992/005406.

SUMMARY OF THE INVENTION

The present invention seeks to provide improved chemical delivery systems and methods. There is thus provided in accordance with a preferred embodiment of the present invention a liquid chemical delivery system including a plurality of at least partially redundant pump modules, each including a programmable logic controller, a human-machine interface and a liquid pumping functionality and being operative to deliver a liquid chemical via a supply line to at least one point of use, a computer network interconnecting the plurality of at least partially redundant pump modules and software for coordinating the operation of the plurality of at least partially redundant pump modules.

Preferably, the at least partially redundant pump modules also each includes at least one functionality selected from among a filtration functionality, a sampling functionality and a drainage functionality.

In accordance with a preferred embodiment of the present invention the liquid chemical delivery system also includes a plurality of at least partially redundant pressure-driven delivery modules, each pressure-driven delivery module including a programmable logic controller connected to the network, a human-machine interface and a plurality of pressure vessels and being controlled by the software and being operative to supply the liquid chemical via a supply line to the point of use at a generally constant flow rate. Additionally, the at least partially redundant pressure- driven delivery modules also each include at least one functionality selected from among a filtration functionality, a sampling functionality and a drainage functionality. Preferably, the liquid chemical delivery system also includes at least one manifold interconnecting the plurality of pump modules and the plurality of at least partially redundant pressurized delivery modules.

In accordance with a preferred embodiment of the present invention the liquid chemical delivery system also includes a tank module including a tank and a programmable logic controller connected to the network and being controlled by the software. Additionally, each of the plurality of at least partially redundant pump modules independently has the capacity to pump a liquid to and from the tank module. Preferably, the liquid chemical delivery system also includes a supply manifold including a plurality of inlet valves, an outlet valve and a programmable logic controller connected to the network, controlled by the software and functional to allow a liquid chemical to be supplied to the system from each of a plurality of containers. Additionally, each of the plurality of at least partially redundant pump modules independently has the capacity to pump a liquid from the containers via the supply manifold. hi accordance with a preferred embodiment of the present invention the at least one point of use includes at least one semiconductor process tool. Preferably, the liquid chemical delivery system also includes a valve manifold box including a plurality of valves, each of the valves being connected to a different one of the at least one point of use and the liquid chemical is delivered to the at least one point of use via the valve manifold box.

Preferably, the network includes at least one master CPU and at least one slave CPU. Additionally, one of the at least one master CPU includes at least two master CPUs and one of the at least one master CPUs controls the system at any particular time.

Li accordance with a preferred embodiment of the present invention the network communicates with the at least one point of use, the at least one point of use being operative to send a request through the network to the system for delivery of a liquid chemical.

Preferably, each of the pump modules can also be controlled manually, hi accordance with a preferred embodiment of the present invention each of the pressure driven delivery modules can also be controlled manually. Preferably, the tank module can also be controlled manually. hi accordance with a preferred embodiment of the present invention the supply manifold can also be controlled manually.

There is also provided in accordance with another preferred embodiment of the present invention a system for controlling chemical delivery systems including a plurality of interconnected network hubs, a link between the programmable logic controller of each of a plurality of points of use and one of the network hubs, a link between the programmable logic controller of each of a plurality of valve manifold boxes and one of the network hubs, a link between a master programmable logic controller of each of a plurality of chemical delivery systems and one of the network hubs, at least one human-machine interface and software for communicating between the points of use, the valve manifold boxes and the chemical delivery systems. Preferably, the software is run locally on the programmable logic controller of each point of use, valve manifold box and chemical delivery system. Additionally or alternatively, the software is programmed via a graphical user interface. There is further provided in accordance with yet another preferred embodiment of the present invention a method for liquid chemical delivery including providing a plurality of at least partially redundant pump modules, each pump module including a programmable logic controller, a human-machine interface and a liquid pumping functionality, interconnecting the plurality of pump modules via a computer network and coordinating the operation of the plurality of at least partially redundant pump modules utilizing the computer network and the programmable logic controllers to deliver a liquid chemical via a supply line to at least one point of use.

Preferably, the method for liquid chemical delivery also includes filtering the liquid chemical. hi accordance with a preferred embodiment of the present invention the coordinating also includes supplying the liquid chemical via the supply line to the at least one point of use at a generally constant flow rate.

Preferably, each of the plurality of at least partially redundant pump modules independently has the capacity to deliver the liquid chemical.

In accordance with a preferred embodiment of the present invention the method for liquid chemical delivery also includes supplying the liquid chemical to the system from each of a plurality of containers. Additionally, each of the plurality of at least partially redundant pump modules independently has the capacity to pump the liquid chemical from the containers.

Preferably, the at least one point of use includes at least one semiconductor process tool. Additionally the method for liquid chemical delivery also includes sending a request through the network for delivery of the liquid chemical to the at least one point of use. BRIEF DESCRIPTION OF THE DRAWINGS

The . present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

Fig. 1 is a simplified illustration of a chemical delivery system constructed and operative in accordance with the present invention;

Figs. 2A, 2B and 2C together are a simplified process and instrumentation diagram of a pump module in accordance with one embodiment of the present invention;

Fig. 3 is a simplified pictorial illustration of the pump module of Figs. 2A-2C;

Figs. 4A, 4B and 4C together are a simplified process and instrumentation diagram of a pressure-driven delivery module in accordance with one embodiment of the present invention;

Fig. 5 is a simplified pictorial illustration of the pressure driven delivery module of Fig. 4;

Figs. 6A, 6B, 6C and 6D are simplified flow diagrams which illustrate four different modes of operation of the pump modules of Figs. 2A-2C; Figs. 7A, 7B and 7C are simplified flow diagrams which illustrate modes of operation of the pump modules of Figs. 2A-2C in a system comprising two such pump modules;

Figs. 8A and 8B are simplified flow diagrams which illustrate modes of operation of the pump modules of Figs. 2A-2C in a system comprising three such pump modules;

Fig. 9 is a simplified schematic illustration of a network for controlling the chemical delivery system of the present invention;

Fig. 10 is a simplified schematic illustration of a master CPU and a slave CPU of the chemical delivery system of the present invention which illustrates the transfer of data between and within the modules of the system;

Fig. 11 is a simplified flowchart illustrating the operation of the master CPU of the chemical delivery system of the present invention; Fig. 12 is a simplified illustration of network connections in a network oriented chemical distribution architecture for controlling the components of a semiconductor fabrication facility in accordance with the present invention; and

Fig. 13 is a simplified illustration of the interfaces of the network oriented chemical distribution architecture of Fig. 12 which illustrates the transfer of data within and between the different interfaces of the architecture.

DETAILED DESCRIPTION OF THE INVENTION

Reference is now made to Fig. 1, which illustrates a chemical delivery system 100 constructed and operative in accordance with the present invention. Chemical delivery system 100 is operative to deliver a liquid chemical from a plurality of containers 102 to a plurality of points of use 104, which are preferably clean room process tools in a semiconductor fabrication facility.

A liquid chemical from any one or more of containers 102 is supplied to a corresponding pneumatically operated valve 108 of a manifold box 110. An outlet of manifold box 110 is coupled via a manifold 112 to a first inlet of each of a plurality of pump modules 114, which are described hereinbelow with reference to Figs. 2 A - 3.

Preferably, a sensor 116 is operative to supply information as to the presence of liquid chemicals at the outlet of manifold box 110 to a programmable logic controller (PLC) 118, which controls valves 108. Alternatively, manifold box 110 may be obviated.

A first outlet of each pump module 114 is coupled via a manifold 120 to a tank module 122, which stores a quantity of a liquid chemical for immediate use. A pneumatically operated valve 123 is preferably operative to control the flow of the liquid chemical into tank module 122, and a pneumatically operated valve 124 is preferably operative to control the flow of the liquid chemical out of tank module 122. Preferably, two sensors 125 are associated with tank module 122 to supply information as to the quantity of liquid chemicals in tank module 122 to a programmable logic controller (PLC) 126, which controls pneumatically operated valves 123 and 124.

An outlet of tank module 122 is coupled via a manifold 128 to a second inlet of each pump module 114. Alternatively, tank module 122 may be obviated.

A second outlet of each pump module 114 is coupled via manifolds 129 and 130 to each of at least one pressure-driven delivery module (PDDM) 132, which is described hereinbelow with reference to Figs. 4 A - 5. Alternatively, PDDMs 132 may be obviated. An outlet of each of PDDMs 132 is coupled via a manifold 134 to at least one valve manifold box (VMB) 136 comprising a plurality of pneumatically operated valves 138 controlled by a programmable logic controller (PLC) 140. Each pneumatically operated valve 138 is coupled to a corresponding point of use 104, which is preferably a clean room process tool in a semiconductor fabrication facility. Alternatively, VMBs 136 may be obviated.

Reference is now made to Figs. 2 A - 2C, which together are a simplified process and instrumentation diagram of a pump module 114 (Fig. 1).

A pneumatically operated pump 148 (Fig. 2B) draws a liquid chemical from containers 102, via a pneumatically operated valve 150, and from tank module 122, via a pneumatically operated valve 152. Pneumatically operated pump 148 is preferably a Mega 960 pump or a Magnum 620 pump manufactured by Trebor International, West Jordan, UT, USA. Downstream of pneumatically operated pump 148, a pulsation dampener 154, such as a Model 85 Surge Suppressor manufactured by Trebor International, West Jordan, UT, USA, is operative to reduce surges in the flow of the liquid chemical. Alternatively, pulsation dampener 154 may be obviated.

Downstream of pulsation dampener 154, a filter housing 156, such as a filter housing manufactured by Pentair Filtration, St. Paul, MN, USA, removes air from the liquid chemical stream and further reduces surges in the flow of the liquid chemical.

Sensors 158 are preferably associated with filter housing 156 to supply information about the volume of air in filter housing 156 to a programmable logic controller (PLC)

160 located in a control box 161 (Fig. 2C). A pneumatically operated valve 162 is operative to remove air from filter housing 156 to a drain manifold 164 (Fig. 2A).

Alternatively, filter housing 156 may be obviated.

Downstream of filter housing 156, filters 166 remove particulate matter from the liquid chemical stream. When maintenance of filters 166 is required, the liquid chemical is drained from filters 166 via pneumatically operated valves 168. Pneumatically operated valves 170 are preferably operative to allow the removal of air from the liquid chemical stream. Alternatively, one or both filters 166 may be obviated.

Upstream of filters 166, a pressure sensor 172, such as Flow-through

Model 4210 NT Pressure Transducer manufactured by Entegris, Chaska, MN, USA, supplies information about the pressure of the liquid chemical stream to PLC 160. Downstream of filters 166, a combined pressure sensor and flow meter 174, such as

Model 4400 NT Electronic Flowmeter manufactured by Entegris, Chaska, MN, USA, supplies information about the pressure and flow rate of the liquid chemical stream to PLC 160. Alternatively, one or both of pressure sensor 172 and combined pressure sensor and flow meter 174 may be obviated.

Downstream of combined pressure sensor and flow meter 174, the liquid chemical is supplied to tank module 122 (Fig. 1) via a pneumatically operated valve 175 and a check valve 176 and to PDDMs 132 (Fig. 1) via a pneumatically operated valve 177 and a check valve 178. When maintenance of pump module 114 is required, the liquid chemical is drained via pneumatically operated valve 180 to drain manifold 164. A check valve 181 ensures one-way flow of the liquid chemical from drain manifold 164 to a drain of the facility. Samples of the liquid chemical from locations upstream and downstream of filters 166 are supplied to a sample box 182 (Fig. 2B) via pneumatically operated valves 183 and 184 respectively. A manually operated valve 187 controls the flow of a sample of the liquid chemical into sample box 182.

Air flows through a conduit 188, which passes through a door switch 189 and is coupled with a pressure sensor 190, located in control box 161 and connected to

PLC 160. When the door to sample box 182 is opened, the flow of air through conduit

188 is disrupted, and pressure sensor 190 detects a change in pressure, which is interpreted by PLC 160 as an indication that the door to sample box 182 is open.

Air flows through a conduit 192, which extends through sample box 182 into a drain 193 and is coupled to a pressure sensor 194 located in control box 161 and connected to PLC 160. When any liquid chemical leaks into sample box 182 and its level rises to the outlet of conduit 192, pressure sensor 194 detects a change in pressure, which is interpreted by PLC 160 as an indication of the presence of leaked liquid chemicals in sample box 182. A liquid collection container 196 in the floor of pump module 114 (Fig.

2A) collects any liquids that leak in pump module 114. Air flows through a conduit 198, which extends into liquid collection container 196 and is coupled to pressure sensors 200 located in control box 161 and connected to PLC 160. When any liquid chemical leaks into liquid collection container 196 and its level rises to the outlet of conduit 198, pressure sensors 200 detect a change in pressure, which is interpreted by PLC 160 as an indication that there are leaked liquid chemicals in liquid collection container 196. A pneumatically operated pump 202 (Fig. 2B) is operative to draw leaked liquid chemicals from compartment 196 via a pneumatically operated valve 204 and from sample box.182 via a pneumatically operated valve 206 and send them to the drain of the facility. Pneumatically operated pump 202 is preferably a Purus 20 pump manufactured by Trebor International, West Jordan, UT, USA. A check valve 208 ensures one-way flow of the liquid chemical from pump 202 to the drain of the facility.

Air flows through a conduit 209, which passes through a door switch 210 (Fig. 2A) and is coupled with a pressure sensor 212, located in control box 161 and connected to PLC 160. When the door to pump module 114 is opened, the flow of air through conduit 209 is disrupted, and pressure sensor 212 detects a change in pressure, which is interpreted by PLC 160 as an indication that the door to pump module 114 is open.

Regulators 214 and needle valves 216 (Fig. 2C) are operative to control the flow of air to the pneumatically operated valves (PV) and pumps, door switches and leak detection conduits in pump module 114. Diaphragm valves 217 are operative to control the flow of air to pumps 148 and 202. A pressure sensor 218 is operative to supply information about the pressure of the air entering pump module 114 to PLC 160.

Nitrogen is supplied to pump module 114 via a pneumatically operated valve 220 and a check valve 222 for the purpose of drying the conduits in pump module 114. A regulator 224 controls the flow of the nitrogen. A pressure sensor 226 is operative to supply information about the pressure of the nitrogen entering pump module 114 to PLC 160.

A manually operated spray device 228 (Fig. 2B) is connected to a supply of deionized water (DI) and when activated is operative to wash the inside of pump module 114. An exhaust fan 230 (Fig. 2A) is preferably operative to remove gases from pump module 114. PLC 160 controls pumps 148 and 202 and the pneumatically operated valves in pump module 114.

Reference is now made to Fig. 3, which is a simplified pictorial illustration of pump module 114. A cabinet 250 preferably made of poly(p-phenylene sulfide) or stainless steel according to the specific chemical supplied by the system houses the elements of pump module 114. A door 252 provides access to all components of pump module 114 for maintenance. Pumps 148 and 202 (Fig. 2B) and filters 166 (Fig. 2A) are seen through door 252. A sample door 254 provides access to sample box 182.

Openings 256 on either side of pump module 114 allow for interconnections between the inputs and outputs of multiple pump modules 114 and

PDDMs 132. It is appreciated that due to this configuration these modules may be placed against a wall and directly adjacent to one another, thus providing a compact chemical delivery system 100.

A control panel 258 enables manual control of pump module 114. A main power switch 260 connects pump module 114 to a power supply, and a power indicator light 262 indicates when pump module 114 is connected to the power supply.

An on/off switch 264 is operative to enable and disable the operation of pump module 114. An emergency shutdown button 266 is operative to disconnect pump module 114 from the power supply. A drain pump button 268 is operative to activate and deactivate the operation of pump 202, which drains leaked liquid chemicals from liquid collection container 196 (Fig. 2A) and sample box 182 (Fig. 2B). Sample buttons 270 and 272 open valves 183 and 184 (Fig. 2A) respectively to allow the withdrawal of a sample of liquid chemical into sample box 182. Sample buttons 270 and 272 are disabled when sample door 254 is open. A touch screen 274 is provided to monitor the operation of pump module 114 and to enter commands.

A light tower 276 comprises three lights which indicate the status of pump module 114. Preferably, a red light 278 indicates a malfunction which prevents operation of pump module 114 or a safety alarm which requires halting the operation of pump module 114. A yellow light 280 indicates a warning of a potential failure in pump module 114. A green light 282 indicates that pump module 114 is fully operational.

Reference is now made to Figs. 4A - 4C, which together are a simplified process and instrumentation diagram of a PDDM 132 (Fig. 1).

Pressure vessels 300 (Fig. 4B) are filled with liquid chemical by pump modules 114 (Fig. 1) via pneumatically operated valves 302. Sensors 304 are preferably

• associated with pressure vessels 300 to supply information about the level of liquid chemical in pressure vessels 300 to a programmable logic controller (PLC) 306 located in a control box 307 (Fig. 4C).

Three-way pneumatically operated valves 308 are operative to admit nitrogen to pressure vessels 300 for discharging the liquid chemical contained therein via pneumatically operated valves 310. Valves 308 also vent excess nitrogen to an exhaust stack 312.

Nitrogen flows via a pneumatically operated valve 314 and a check valve

316 to drive the liquid chemical downstream of pneumatically operated valves 310 through PDDM 132. Regulator 318 (Fig. 4C) regulates the flow of nitrogen into PDDM 132, and pressure sensor 319 is operative to supply information about the pressure of said nitrogen to PLC 306.

Downstream of valves 310, filters 320 (Fig. 4A) remove particulate matter from the liquid chemical stream. When maintenance of filters 320 is required, the liquid chemical is drained from filters 320 via pneumatically operated valves 322. Pneumatically operated valves 324 are preferably operative to remove air from the liquid chemical stream. Alternatively, one or both filters 320 may be obviated.

Upstream of filters 320, a pressure sensor 326 supplies information about the pressure of the liquid stream to PLC 306. Downstream of filters 320, a combined pressure sensor and flow meter 328 supplies information about the pressure and flow rate of the liquid stream to PLC 306. Alternatively, one or both of pressure sensor 326 and combined pressure sensor and flow meter 328 may be obviated.

Downstream of combined pressure sensor and flow meter 328, the liquid chemical is supplied to VMBs 136 (Fig. 1) via a pneumatically operated valve 330 and a check valve 332. When maintenance of PDDM 132 is required, the liquid chemical is drained via a pneumatically operated valve 334 to a drain manifold 336. A check valve 338 ensures one-way flow of liquid chemicals from drain manifold 336 to a drain of the facility.

Samples of the liquid chemical from locations upstream and downstream of filters 320 are supplied to a sample box 340 (Fig. 4A) via pneumatically operated valves 341 and 342 respectively. A manually operated valve 346 controls the flow of a sample of the liquid chemical into sample box 340. Air flows through a conduit 347, which passes through a door switch 348 and is coupled with a pressure sensor 350, located in control box 307 and connected to

PLC 306. When the door to sample box 340 is opened, the flow of air through conduit

347 is disrupted, and pressure sensor 350 detects a change in pressure, which is interpreted by PLC 306 as an indication that the door to sample box 340 is open.

Air flows through a conduit 352, which extends through sample box 340 into a drain 353 and is coupled to a pressure sensor 354 located in control box 307 and connected to PLC 306. When any liquid chemical leaks into sample box 340 and its level rises to the outlet of conduit 352, pressure sensor 354 detects a change in pressure, which is interpreted by PLC 306 as an indication of the presence of leaked liquid chemicals in sample box 340.

A liquid collection container 356 in the floor of PDDM 132 (Fig. 4A) collects any liquids that leak in PDDM 132. Air flows through a conduit 358, which extends into liquid collection container 356 and is coupled to pressure sensors 360 located in control box 307 and connected to PLC 306. When any liquid chemical leaks into liquid collection container 356 and its level rises to the outlet of conduit 358, pressure sensors 360 detect a change in pressure, which is interpreted by PLC 306 as an indication that there are leaked liquid chemicals in liquid collection container 356.

A pneumatically operated pump 362 (Fig. 4A) is operative to draw leaked liquid chemicals from compartment 356 via a pneumatically operated valve 364 and from sample box 340 via a pneumatically operated valve 366 and send them to the drain of the facility. A check valve 368 ensures one-way flow of the liquid chemical from pump 362 to the drain of the facility.

Air flows through a conduit 369, which passes through a door switch 370 (Fig. 4A) and is coupled with a pressure sensor 372, located in control box 307 and connected to PLC 306. When the door to PDDM 132 is opened, the flow of air through conduit 369 is disrupted, and pressure sensor 372 detects a change in pressure, which is interpreted by PLC 306 as an indication that the door to PDDM 132 is open.

Regulators 374 and needle valves 376 (Fig. 4C) are operative to control the flow of air to the pneumatically operated valves (PV) and the pump, door switches and leak detection conduits in PDDM 132. Diaphragm valve 377 is operative to control the flow of air to pump 362. A pressure sensor 378 is operative to supply information about the pressure of the air entering PDDM 132 to PLC 306.

A manually operated spray device 380 (Fig. 4A) is connected to a supply of deionized water (DI) and when activated is operative to wash the inside of PDDM 132. An exhaust fan 382 (Fig. 4B) is preferably operative to remove gases from PDDM 132. PLC 306 controls the pneumatically operated valves and pump 362 in PDDM 132. Reference is now made to Fig. 5, which is a simplified pictorial illustration of PDDM 132. A cabinet 400 preferably made of poly(p-phenylene sulfide) or stainless steel according to the specific chemical supplied by the system houses the elements of PDDM 132.

A door 402 provides access to all components of PDDM 132 for maintenance. Pressure vessels 300 (Fig. 4B), drain pump 362 and filters 320 (Fig. 4A) are seen through door 402. A sample door 404 provides access to sample box 340 (Fig. 4A). Openings 406 on either side of PDDM 132 allow for interconnections between the inputs and outputs of multiple PDDMs 132 and pump modules 114. It is appreciated that due to this configuration these modules may be placed against a wall and directly adjacent to one another, thus providing a compact chemical delivery system 100. A control panel 408 enables manual control of PDDM 132. A main power switch 410 connects PDDM 132 to a power supply, and a power indicator light 412 indicates when PDDM 132 is connected to the power supply.

An on/off switch 414 is operative to enable and disable the operation of PDDM 132. An emergency shutdown button 416 is operative to disconnect PDDM 132 from its power supply.

A drain pump button 418 is operative to activate and deactivate the operation of drain pump 362, which drains leaked liquid chemicals from liquid collection container 356 and sample box 340 (Fig. 4A). Sample buttons 420 and 422 open valves 341 and 342 (Fig. 4A) respectively to allow the withdrawal of a sample of liquid chemical into sample box 340. Sample buttons 420 and 422 are disabled when sample door 404 is open. A touch screen 424 is provided to monitor the operation of

PDDM 132 and to enter commands. A light tower 426 comprises three lights which indicate the status of

PDDM 132. Preferably, a red light 428 indicates a malfunction which prevents operation of PDDM 132 or a safety alarm which requires halting the operation of

PDDM 132. A yellow light 430 indicates a warning of a potential failure in PDDM 132. A green light 432 indicates that PDDM 132 is fully operational.

Reference is now made to Figs. 6A - 6D, which illustrate four different modes of operation of a pump module 480 such as the one described in reference to

Figs. 2 A - 3. Fig. 6 A shows a supply mode in which a liquid chemical is pumped by pump module 480 from containers 102 via pneumatically operated valves 108 in manifold 110 to tank module 122. Fig. 6B shows a delivery mode in which the liquid chemical is pumped by pump module 480 from tank module 122 to PDDMs 132. Fig.

6C shows a circulation mode in which the liquid chemical stored in tank module 122 is circulated through pump module 480 in order to filter it. Fig. 6D shows a direct delivery mode in which the liquid chemical is pumped by pump module 480 from containers 102 directly to PDDMs 132.

Reference is now made to Figs. 7A - 7C, which illustrate modes of operation of pump modules 114 in a system comprising two such pump modules. A first pump module 480 pumps a liquid chemical from containers 102 via pneumatically operated valves 108 in manifold 110 to tank module 122. A second pump module 482 pumps the liquid chemical from to tank module 122 to PDDMs 132 (Fig. 7A).

When the level of the liquid chemical in tank module 122 is low, second pump module 482 pumps the liquid chemical directly from containers 102 to PDDMs

132 while first pump module 480 fills tank module 122 (Fig. 7B). When tank module

122 is full, the chemical stored therein is circulated through first pump module 480 (Fig. 7C).

Reference is now made to Figs. 8A and 8B, which illustrate modes of operation of pump modules 114 in a system comprising three such pump modules.

Preferably, first pump module 480 and second pump module 482 operate as in the system comprising only two pump modules 480 and 482, shown in Figs. 7A - 7C, while a third pump module 484 is normally in standby mode.

When the demand for the liquid chemical is higher than that which second pump module 482 can alone provide, third pump module 484 operates in the delivery mode (Fig. 6B) together with second pump module 482 to increase the output of the liquid chemical from chemical delivery system 100 (Fig. 8A). When the level of the liquid chemical in tank module 122 is low, third pump module 484 operates in the direct delivery mode (Fig. 6D) together with second pump module 482 to increase the output of the liquid chemical from chemical delivery system 100, while first pump module 480 fills tank module 122 (Fig 8B).

It is appreciated that when any one of pump modules 480, 482 and 484 is not operational, a system controlling the pump modules is able to reassign the tasks of each remaining pump module in order to maintain operation of chemical delivery system 100. It is also appreciated that a fourth pump module (not shown) may be added to the chemical delivery system 100 to serve as an additional backup for pump modules 480, 482 and 484.

Reference is now made to Fig. 9, which is a simplified schematic illustration of a network for controlling the operation of chemical delivery system 100. The network is preferably a Chemical Delivery System (CDS) Interface 490 of a network oriented chemical distribution architecture (NOCDA) system described hereinbelow in reference to Figs. 12 and 13. The PLCs 160 of two pump modules 114

(Fig. 1) serve as master CPUs 500 and 502. The PLCs of the remaining modules of system 100, such as PLC 118 of manifold box 110, PLCs 160 of additional pump modules 114, PLC 126 of tank module 122 and PLCs 306 of PDDMs 132 (Fig. 1), serve as slaves 504.

The modules of system 100 are connected by a hub 506 with Ethernet connections 508. Another hub 510 connects master modules 500 and 502 to a system

511, such as the NOCDA system described hereinbelow with reference to Figs. 12 and 13, which delivers requests for a liquid chemical from points of use 104 (Fig. 1), which are preferably clean room process tools in a semiconductor fabrication facility.

Each of master CPUs 500 and 502 preferably runs four blocks of software. An Interface Block 512 communicates with system 511. A Network Management Block 514 communicates with the other modules in chemical delivery system 100.

First master CPU 500 reads data from and sends commands to all of the modules of system 100. Normally, second master CPU 502 only reads data. When second master CPU 502 fails to communicate with first master CPU 500, second master CPU 502 takes over the role of sending commands.

A Function Management Block 516 decides in which mode each pump module 114 should operate. A Unit Process Control Block 518 controls the module hosting the master CPU based on data received from the Network Management Block 514 or from the local control panel.

Each Slave CPU 504 preferably runs two blocks of software. A Unit

Network Management Block (UNM) 520 communicates with master CPUs 500 and

502. Unit Process Control Block (UPC) 518 controls the module hosting the slave CPU based on data received from the Unit Network Management Block 520 or from the local control panel.

Reference is now made to Fig. 10, which is a simplified schematic illustration of a master CPU 500 and a slave CPU 504 of chemical delivery system 100 and illustrates the transfer of data between and within the modules of chemical delivery system 100. Interface blocks 512 of master CPUs 500 and 502 receive fill requests 550 from system 511. Preferably, system 511 sends fill requests 550 from a VMB 136 (Fig.

1).

Each fill request 550 preferably comprises the following information: a. the length of time to deliver the chemical; b. the number of the valve on the VMB 136 making the request; and c. the IP address of the VMB 136.

Fill requests 550 are stored in fill request stack 552, and master CPU 500 preferably returns an acknowledgement 554 to the VMB 136 sending the request.

Each master CPU 500 and 502 has a set of module data tables 556, one for each module in the system, each of which preferably comprises the following data about the status of the module: a. the IP address of the module; b. the status of the module (enabled, disabled, communication error); c. the command that the module is executing; d. the status of the sensors in the module; e. the status of the valves and pumps in the module; and f. the readings of the pressure and flow meters in the module. Module data tables 556 also comprise a command to be sent to the module. Network management block 514 of master 500 writes the commands from module data tables 556 to a local data table 558 in unit process control block 518 of its own module, that of master 502 via its network management block 514 and that of every slave 504 via its unit network management block 520. Masters 500 and 502 then read the status of every module from its local data table 558 and write the data to module data tables 556.

Function management block 516 preferably reads fill requests 550 from fill request stack 552 and the status of each of the modules from module data tables 556 and runs a routine to assign tasks to each of the modules. The tasks are written to module data tables 556 as commands.

Reference is now made to Fig. 11, which is a flowchart of the operation of master CPU 500. Each cycle begins with the master's own unit process control block 518 executing the command written by network management block 514 in table 558. Based on the command received, the master module opens and closes valves and operates pumps as necessary to fulfill the command. The master module stores the status of the sensors, valves and switches in local data table 558.

Next, network management block 514 communicates with each of the modules including the modules hosting the master CPUs. First the status of a module is read. If the module is disabled, the master skips to the next module. If the module is not disabled, the master writes the command stored in the corresponding module data table 556 to the local data table 558 of the module. Then the master reads the remainder of the status of the module and writes it to the module data table 556 in the master.

If the command being executed by the module is not the most recent command given to the module, the module's status in module data table 556 (Fig. 10) is set to 'communication error.' In addition, module data table 556 preferably comprises an additional 1-bit component that the master changes from 1 to 0 or from 0 to 1 each time it communicates with the module. If the master detects that the value of this bit is static, the module's status in module data table 556 is set to 'communication error.' After communicating with each module, master CPU 500 runs the function management block 516 routine to generate commands for the modules and write them in module data tables 556. Interface block 512 then communicates with system 511 to receive fill requests 550 and send acknowledgements of the fill requests 554 back to system 511. A fill request 550 may also serve as a cancellation of a prior fill request 550 received from a point of use 104 when the same point of use 104 sends a fill request 550 whose time value is 0. Reference is now made to Fig. 12, which is a simplified illustration of network connections in a network oriented chemical distribution architecture (NOCDA) 600 for controlling the components of a semiconductor fabrication facility. NOCDA 600 comprises a plurality of hubs 602 to which are connected VMBs 136, process tools 104 and master modules 500 and 502 of the chemical delivery systems 100 in the facility. Also connected to hubs 602 are a plurality of human-machine interfaces 604.

The software controlling NOCDA 600 is run locally on the PLC of each process tool 104, VMB 136 and master modules 500 and 502 of chemical delivery systems 100. It is appreciated that owing to this design, a failure in any one component connected to NOCDA 600 results in a local disruption of liquid chemical delivery only. The delivery in the remainder of the plant that does not use the failed process tool 104, VMB 136 or chemical delivery system 100 is maintained.

Reference is now made to Fig. 13, which is a simplified illustration of interfaces of NOCDA 600 and the transfer of data within and between the interfaces. A

Tool Interface 606 receives inputs from process tools 104 (Fig. 1) and communicates with a VMB Interface 608. VMB Interface 608 controls the valves 138 in VMBs 136

(Fig. 1) and communicates with Chemical Delivery System Interface 490 (Fig. 9).

The PLC of each process tool 104 may comprise up to eight input channels, each preferably connected to a valve 138 of a VMB 136 for supplying a different chemical to the process tool 104. An input device 610 for each chemical used by the tool is provided for requesting the chemical.

A channel parameters table 612 is preferably stored on the PLC of each process tool. Each entry in channel parameters table 612 contains data relating to one of the connected input channels comprising: a. the number valve 138 on VMB 136 to which the process tool channel is connected; b. the IP address of the VMB 136; c. the amount of time the chemical should be delivered; and d. the number of the VMB 136 in the NOCDA system.

A buffer table 614 consisting of one entry for each channel stores data to be sent to and data received from VMBs 136. Each entry in this table comprises: a. the status of the connected VMB 136; b. the channel number on the process tool 104 to which the VMB 136 is connected; c. the IP address of the process tool 104; and d. the amount of time the chemical should be delivered.

Similarly, on the PLC 140 of each VMB 136 is stored a channel parameters table 616 wherein each entry comprises data relating to one of the valves 138 of the VMB 136. Each entry in channel parameters table 616 comprises: a. the channel number on the process tool 104 to which the VMB 136 is connected; b. the IP address of the connected chemical delivery system 100; c. the amount of tune the chemical should be delivered; and d. the number of the VMB 136 in the NOCDA system.

A buffer table 618 comprising one entry for each valve 138 stores data to be sent to and data received from the process tools 104 and chemical delivery systems 100. Each entry in this table comprises: a. the status of the VMB 136 and connected chemical delivery system

100; b. the number valve 138 on the VMB 136 to which the process tool 104 is connected; c. the IP address of the VMB 136; and d. the amount of time the chemical should be delivered.

Tables 612, 614, 616 and 618 are programmed by the operator through one of human-machine interfaces 604 (Fig. 12). The connections between a process tool 104 and a VMB valve 138 or a VMB 136 and a chemical delivery system 100 are programmed visually by means of the NOCDA user interface. The NOCDA user interface also allows monitoring of the status of every component of NOCDA 600, such as process tools 104, VMBs 136 and chemical delivery systems 100 comprising a manifold 110, pump modules 114, tank module 122 and PDDMs 132. A logic module 619 in the tool interface 606 of NOCDA 600 continuously scans inputs 610. When an input 610 is activated, logic module 619 reads the duration of time to request the chemical from channel parameters table 612 and copies it into the corresponding entry in buffer table 614. Communications module 620 scans buffer table 614, and if one of the time entries is greater than zero, it sends a message 622 to the VMB listed in channel parameters table 612 comprising: a. the number valve on the VMB to which the process tool is connected; b. the time to hold the valve open; and c. the IP address of the process tool.

Communications module 624 of the VMB interface 608 of NOCDA 600 reads message 622 and stores it in the corresponding entry in buffer table 618, sets the VMB status to 1 and returns an acknowledgement 627 to the tool interface comprising: a. the status of the valve on the VMB; and b. the channel number on the process tool to which the VMB is connected, which is read from channel parameters table 616.

A logic module 628 of VMB interface 626 scans buffer table 618, and if any time entry is greater than zero it creates a fill request 550 (Fig. 10) comprising: a. the amount of time to supply the chemical; b. the IP address of the VMB; and c. the number valve on the VMB requesting the chemical.

The fill request 550 is sent to the chemical delivery system 100 listed in channel parameters table 616. An acknowledgement 554 is received from the chemical delivery system 100. It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as modifications thereof which would occur to a person of skill in the art upon reading the foregoing description and which are not in the prior art.

Claims

1. A liquid chemical delivery system comprising: a plurality of at least partially redundant pump modules, each including a programmable logic controller, a human-machine interface and a liquid pumping functionality and being operative to deliver a liquid chemical via a supply line to at least one point of use; a computer network interconnecting said plurality of at least partially redundant pump modules; and software for coordinating the operation of said plurality of at least partially redundant pump modules.

2. A liquid chemical delivery system according to claim 1 wherein said at least partially redundant pump modules also each includes at least one functionality selected from among a filtration functionality, a sampling functionality and a drainage functionality.

3. A liquid chemical delivery system according to claim 1 and also comprising a plurality of at least partially redundant pressure-driven delivery modules, each pressure-driven delivery module including a programmable logic controller connected to said network, a human-machine interface and a plurality of pressure vessels and being controlled by said software and being operative to supply said liquid chemical via a supply line to said point of use at a generally constant flow rate.

4. A liquid chemical delivery system according to claim 3 wherein said at least partially redundant pressure-driven delivery modules also each includes at least one functionality selected from among a filtration functionality, a sampling functionality and a drainage functionality.

5. A liquid chemical delivery system according to claim 3 and also comprising at least one manifold interconnecting said plurality of pump modules and said plurality of at least partially redundant pressurized delivery modules.

6. A liquid chemical delivery system according to claim 1 and also comprising a tank module including a tank and a programmable logic controller connected to said network and being controlled by said software.

7. A liquid chemical delivery system according to claim 6 wherein each of said plurality of at least partially redundant pump modules independently has the capacity to pump a liquid to and from said tank module.

8. A liquid chemical delivery system according to claim 1 also comprising a supply manifold including a plurality of inlet valves, an outlet and a programmable logic controller connected to said network, controlled by said software and functional to allow a liquid chemical to be supplied to said system from each of a plurality of containers.

9. A liquid chemical delivery system according to claim 8 wherein each of said plurality of at least partially redundant pump modules independently has the capacity to pump a liquid from said containers via said supply manifold.

10. A liquid chemical delivery system according to claim 1 wherein said at least one point of use comprises at least one semiconductor process tool.

11. A liquid chemical delivery system according to claim 1 and also comprising a valve manifold box including a plurality of valves, each of said valves being connected to a different one of said at least one point of use and wherein said liquid chemical is delivered to said at least one point of use via said valve manifold box.

12. A liquid chemical delivery system according to claim 1 wherein said network comprises at least one master CPU and at least one slave CPU.

13. A liquid chemical delivery system according to claim 12 wherein: said at least one master CPU comprises at least two master CPUs; and one of said at least two master CPUs controls the system at any particular time.

14. A liquid chemical delivery system according to claim 1 and wherein said network communicates with said at least one point of use, said at least one point of use being operative to send a request through said network to said system for delivery of a liquid chemical.

15. A liquid chemical delivery system according to claim 1 wherein each of said pump modules can also be controlled manually.

16. A liquid chemical delivery system according to claim 3 wherein each of said pressure driven delivery modules can also be controlled manually.

17. A liquid chemical delivery system according to claim 6 wherein said tank module can also be controlled manually.

18. A liquid chemical delivery system according to claim 8 wherein said supply manifold can also be controlled manually.

19. A system for controlling liquid chemical delivery systems comprising: a plurality of interconnected network hubs; a link between the programmable logic controller of each of a plurality of points of use and one of said network hubs; a link between the programmable logic controller of each of a plurality of valve manifold boxes and one of said network hubs; a link between at least one master programmable logic controller of each of a plurality of chemical delivery systems and one of said network hubs; at least one human-machine interface; and software for communicating between said points of use, said valve manifold boxes and said chemical delivery systems.

20. A system according to claim 19 wherein said software is run locally on the programmable logic controller of each point of use, valve manifold box and chemical delivery system.

21. A system according to claim 19 wherein said software is programmed via a graphical user interface.

22. A method for liquid chemical delivery comprising: providing a plurality of at least partially redundant pump modules, each pump module including a programmable logic controller, a human-machine interface and a liquid pumping functionality; interconnecting said plurality of pump modules via a computer network; and coordinating the operation of said plurality of at least partially redundant pump modules utilizing said computer network and said programmable logic controllers to deliver a liquid chemical via a supply line to at least one point of use.

23. A method for liquid chemical delivery according to claim 22 and also comprising filtering said liquid chemical.

24. A method for liquid chemical delivery according to claim 22 and wherein said coordinating also comprises supplying said liquid chemical via said supply line to said at least one point of use at a generally constant flow rate.

25. A method for liquid chemical delivery according to claim 22 wherein each of said plurality of at least partially redundant pump modules independently has the capacity to deliver said liquid chemical.

26. A method for liquid chemical delivery according to claim 22 and also comprising supplying said liquid chemical to said system from each of a plurality of containers.

27. A method for liquid chemical delivery according to claim 26 wherein each of said plurality of at least partially redundant pump modules independently has the capacity to pump said liquid chemical from said containers.

28. A method for liquid chemical delivery according to claim 22 wherein said at least one point of use comprises at least one semiconductor process tool.

29. A method for liquid chemical delivery according to claim 22 and also comprising sending a request through said network for delivery of said liquid chemical to said at least one point of use.