Connecting and disconnecting the cooling loop of a refrigeration system

Abstract

A control system is disclosed for controlling the flow of coolant between a refrigeration system and a cooling loop in a semiconductor processing chamber such that leakage of coolant is inhibited when the refrigeration system is connected to or disconnected from the cooling loop, the control system comprising an inlet valve configured to selectively isolate or connect a supply path for supplying coolant from the refrigeration system to an inlet of the cooling loop, an outlet valve configured to selectively isolate or connect a return path for returning coolant to the refrigeration system to an outlet of the cooling loop, a coolant return path for recovering coolant from the refrigeration system and a coolant return valve configured to selectively isolate or connect the cooling loop to a pressure sensor for determining the pressure of the coolant in the cooling loop, an input for receiving disconnect and connect commands for the cooling loop, and a control circuit configured to receive signals from the pressure sensor and commands from the input and responsively generate control signals for controlling the opening and closing of the inlet valve, the outlet valve, and the coolant return valve.

Description

[Technical Field]

[0001] The field of the invention relates to controlling the flow of refrigerant when connecting or disconnecting a cooling loop in a semiconductor processing chamber from a refrigeration system. [Background technology]

[0002] With the new and evolving requirements for cooling semiconductor wafers to ever lower temperatures, there is a push in the industry to directly cool semiconductor wafers using refrigerants instead of using secondary heat transfer fluids as the heat transfer medium. While traditional heat transfer fluids have been liquids, when direct cooling is utilized, the refrigerant can be in liquid, gas, or mixed phases. While the ability of a refrigerant to change phase is advantageous from a heat transfer perspective, it presents special challenges when the cooling device (e.g., semiconductor chuck, cooling plate) needs to be connected or disconnected from the refrigeration system.

[0003] It is illegal and environmentally irresponsible to allow refrigerant to be released into the environment. Therefore, care must be taken when disconnecting a chiller from a refrigeration system to ensure that refrigerant is not released into the atmosphere. To accomplish this, a complex process must be followed to ensure that substantially all of the refrigerant in the chiller and connecting piping is vented before the chiller is disconnected.

[0004] Conversely, when a cooling device is installed or connected, the system must be leak tested before semiconductor wafer processing begins. The process required to achieve zero or near-zero coolant leakage is complex and labor intensive.

[0005] Semiconductor process chambers are typically located in clean rooms, away from refrigeration systems that may be in sub-fabs. This makes connection or disconnection more complex. Additionally, such systems may require the refrigeration system to be disconnected from the cooling loop more regularly than traditional systems, making it even more important that the connection / disconnection process be efficient, reliable, and repeatable. Summary of the Invention [Means for solving the problem]

[0006] A first aspect provides a control system for controlling the flow of coolant between a refrigeration system and a cooling loop in a semiconductor processing chamber so as to reduce coolant leakage when the refrigeration system is connected to or disconnected from the cooling loop, the control system comprising: an inlet valve configured to selectively block or connect an inlet of the cooling loop to a supply path for supplying coolant from the refrigeration system; an outlet valve configured to selectively block or connect an outlet of the cooling loop to a return path for returning coolant to the refrigeration system; a coolant recovery valve configured to selectively block or connect the cooling loop to a coolant recovery path for recovering coolant for the refrigeration system; a pressure sensor for determining the pressure of the coolant in the cooling loop; an input for receiving commands to disconnect and connect the cooling loop; and a control circuit configured to receive signals from the pressure sensor and commands from the input and to generate control signals in response to control the opening and closing of the inlet valve, outlet valve and coolant recovery valve.

[0007] The inventors of the present invention have recognized the problems associated with connecting and disconnecting a direct-cooled refrigeration loop to a refrigeration system, particularly the problems associated with the potential for leakage of refrigerant into the environment associated with such a process. Furthermore, if the loop is to be connected and disconnected periodically, it is important that this be done in a repeatable, reliable, and efficient manner, as well as to minimize leakage.

[0008] One way to ensure reliability and repeatability, and actually improve efficiency, is to automate such processes. Accordingly, the inventors have provided a refrigeration system with control circuitry and automatically controlled valves, allowing the connection and disconnection process to be automatically controlled in a self-contained system that minimizes manual intervention and does not require a separate refrigeration recovery unit.

[0009] In such a system, the flow of refrigerant into and out of the cooling loop can be controlled, the condition of the cooling loop can be monitored by a pressure sensor, and a control circuit can automatically respond to measurements from the pressure sensor to control the flow of refrigerant and the connection and disconnection of various parts of the system.

[0010] Valves can be controlled to disconnect or connect the cooling loop to the refrigeration system at the appropriate times, and pumps are used to move the refrigerant. Thus, a system is provided having automatic control components that can reliably and repeatably control the flow and disconnection of refrigerant with minimal manual intervention. Thus, the system can automatically place the refrigeration system and cooling loop in the appropriate state to allow the loop to be connected or disconnected in a safe, leak-free manner.

[0011] In some embodiments, the control circuit is configured to, in response to receiving a command to disconnect the cooling loop, control the compressor of the refrigeration system to turn off; control the inlet valve and the outlet valve to close; control the refrigerant recovery valve to open; operate a pump to pump refrigerant from the cooling loop along a refrigerant recovery path towards the refrigeration system; determine the pressure in the cooling loop from a pressure sensor, and in response to the pressure being below a predetermined discharge value, control the pump to turn off; control the refrigerant recovery valve to close; and after a predetermined time, determine whether the pressure in the cooling loop has risen by more than a predetermined amount, and if not, generate an indication that the cooling loop can be safely disconnected from the refrigeration system.

[0012] Upon receiving a disconnect command, the control circuit stops the refrigeration process by turning off the compressor and then ensures that the inlet and outlet valves connecting the refrigerant supply and return paths to the cooling loop are closed. The control circuit then controls the refrigerant recovery valve to open, thereby providing a fluid flow path from the cooling loop to the refrigeration system. The pump then activates to pump fluid along this path from the cooling loop, and the pressure within the cooling loop is monitored. When the pressure drops to a low value, indicating that there is little refrigerant remaining in the cooling loop, the pump is turned off and the refrigerant recovery valve is closed; these two steps can occur simultaneously or in either order. After a predetermined time, it is determined whether the pressure within the cooling loop has changed by more than a certain amount, which can be done by measuring the rate of pressure change or by monitoring the actual value. If it is determined that the pressure has not increased excessively, this indicates that the system is leak-free, and an indication is provided to the user that the cooling loop can be safely disconnected from the system.

[0013] In some embodiments, the pump includes a compressor.

[0014] The pump is necessary so that the control system can control the movement of refrigerant from the cooling loop prior to disconnection. A pump in the form of a compressor is already present in the refrigeration system, and in some embodiments, this compressor can be used under the control of the control circuit to pump refrigerant from the cooling loop.

[0015] Alternatively, the control system may include a dedicated pump configured to pump refrigerant from the cooling loop along the refrigerant return path.

[0016] An alternative may be to have a dedicated pump within the control system, which has the advantage that the pump is sized and capacity specifically adapted to exhausting the cooling loop, allowing the process to run efficiently. This may be particularly useful where the compressor in the refrigeration system is too large for this operation or is unsuitable due to suction pressure limitations, or where there are multiple compressors in the refrigeration system.

[0017] In some embodiments, the control system further comprises a buffer volume provided on the refrigerant recovery path and a further valve configured to selectively isolate or connect the refrigerant recovery path to the compressor, and the control circuit is configured to control the further valve to close before activating the pump, such that, upon activation, the pump pumps refrigerant from the cooling loop to the buffer volume.

[0018] If there is a dedicated pump on the refrigerant return path, a buffer volume may be provided on this path to collect refrigerant exhausted from the cooling loop. In this case, an additional valve may be provided to isolate the refrigerant return path from the refrigeration system so that the buffer volume collects refrigerant when the cooling loop is exhausted. This allows the dedicated pump to be isolated from the compressor and the high-pressure side of the refrigeration system during this process.

[0019] In some embodiments, the control system further comprises a return path valve configured to selectively isolate or connect the return path from the compressor, and the control circuit is configured to control the return path valve to close when controlling the inlet valve and the outlet valve to close.

[0020] In some embodiments, a valve is provided to isolate the return path from the compressor during exhaust of the control loop to prevent refrigerant from flowing backward through this path as it is pumped from the cooling loop.

[0021] In some embodiments, the control system further includes a bypass valve configured to selectively block or connect a warmer refrigerant bypass path for supplying warmer refrigerant from the compressor, and the control circuit is configured to control the bypass valve to close when controlling the inlet valve and the outlet valve to close.

[0022] In some embodiments, a bypass path can be present to supply warmed refrigerant to the refrigerant supply path. In some embodiments, it may be advantageous to have separate valves to isolate the refrigerant supply path and the bypass path from the cooling loop. In this regard, the two paths carry fluids at significantly different temperatures, and therefore, by having separate valves for the two paths, these valves can be set to match the operating temperature of the path in which they are located. Using a single valve downstream of the junction of the two paths would be subject to larger temperature fluctuations, deteriorate faster, and / or require more expensive components. Therefore, in some embodiments, two separate valves are provided, both of which are sources of refrigerant to the cooling loop and are therefore separately controlled by the control system.

[0023] In some embodiments, the control system includes a trace gas source and a trace gas valve configured to selectively isolate or connect the trace gas source to the cooling loop, and the control circuitry is configured to control the trace gas valve.

[0024] To allow the cooling loop to be leak tested without incurring loss of refrigerant, a trace gas source and trace gas valve can be provided for selective connection to the cooling loop, which can be filled with trace gas to a predetermined pressure to determine leaks. The trace gas can include an inert gas such as dry nitrogen, high-pressure helium, or some other gas such as R134A.

[0025] In some embodiments, the control system includes an exhaust valve that selectively isolates or connects the cooling loop and the pump, and the control circuit is configured to control the exhaust valve.

[0026] The control system may also include a vent valve and connection to a pump for venting the cooling loop, which may be advantageous when venting fluid from the cooling loop that should not be sent to the refrigeration system, such as when the cooling loop is filled with a trace gas.

[0027] In some embodiments, the control system is configured to: control the inlet valve, outlet valve, refrigerant recovery valve, and exhaust valve to close in response to receiving a connection command for the cooling loop; control the trace gas valve to open so that trace gas from the trace gas source flows into the cooling loop; determine the pressure in the cooling loop and control the trace gas valve to close in response to the pressure rising above a predetermined leak test value; determine whether the pressure in the cooling loop has dropped by more than a predetermined leak test amount after a predetermined time, and if not, control the exhaust valve to open so that trace gas is exhausted from the cooling loop; determine the pressure in the cooling loop and control the exhaust valve to close in response to the pressure dropping below the predetermined exhaust value; and determine the pressure in the cooling loop and control the exhaust valve to close in response to the pressure rising below the predetermined leak amount, indicating that the cooling loop is properly connected to the refrigeration system.

[0028] In addition to controlling the disconnection of the cooling loop from the system with minimal refrigerant leakage, embodiments may also control the connection so that the connection is made in a leak-free manner.

[0029] To accomplish this, the trace gas source can be provided with an automatically controllable valve that, when connected to the refrigeration system, fills the cooling loop with trace gas to a predetermined pressure, with any pressure leaks detected by a pressure sensor. Once the cooling loop is determined to be sufficiently leak-free, an exhaust valve can be opened to exhaust the trace gas. At this point, an indication can be provided to the operator that the connection is leak-free, and the refrigeration system can be started.

[0030] In some embodiments, the control system is configured to open the further valve in response to an indication that the cooling loop is properly connected to the refrigeration system, and to close the further valve after a predetermined time before starting the refrigeration system.

[0031] If the control system has a separate pump and buffer volume, before restarting the refrigeration system, an additional valve located between the buffer volume and the compressor must be opened to allow the refrigerant recovered from the cooling loop to return to the refrigeration system, and then closed to isolate this path from the compressor.

[0032] In some embodiments, the control system is configured to: Controlling the refrigerant recovery valve, the trace gas valve, and the exhaust valve to close; Controlling the inlet valve and the outlet valve to open; Activate the compressor, It is structured as follows.

[0033] Once the system is properly connected and there is a buffer volume where stored refrigerant is being returned to the refrigeration system, the refrigeration system can be started. To start, it is necessary to ensure that the refrigerant recovery valve, trace gas valve, and exhaust valve are closed, open the inlet and outlet valves, and run the compressor.

[0034] A second aspect provides a refrigeration system for supplying a refrigerant to a cooling loop in a semiconductor processing chamber, the refrigeration system comprising: A compressor; a refrigerant supply path for supplying refrigerant from the compressor to the cooling loop; a refrigerant return path for receiving refrigerant from the cooling loop and returning the refrigerant to the compressor; at least one heat exchanger for exchanging heat between the refrigerant supply path and the refrigerant return path; a control system according to the first aspect; Equipped with.

[0035] A third aspect provides a method for controlling coolant flow between a refrigeration system and a cooling loop in a semiconductor processing chamber such that coolant leakage is inhibited upon decoupling of the refrigeration system from the cooling loop, the method comprising: controlling a compressor of the refrigeration system to be off; controlling an inlet valve of the refrigerant supply path and an outlet valve of the refrigerant return path to close; a step of controlling a refrigerant recovery valve of a refrigerant recovery path to open; operating a pump to pump refrigerant from the cooling loop along a refrigerant recovery path towards a refrigeration system; determining a pressure in the cooling loop and, in response to the pressure being below a predetermined exhaust value, controlling the pump to be off; controlling the refrigerant recovery valve to close; After a predetermined time, determining whether the pressure in the cooling loop has risen by more than a predetermined amount, and if not, generating an indication that it is safe to disconnect the cooling loop from the refrigeration system.

[0036] A fourth aspect provides a method for controlling coolant flow between a refrigeration system and a cooling loop in a semiconductor processing chamber such that coolant leakage is inhibited when connecting the refrigeration system to the cooling loop, the method comprising: controlling the inlet valve, the outlet valve, the refrigerant recovery valve, and the exhaust valve to close; controlling a trace gas valve to open so that trace gas from a trace gas source flows into the cooling loop; determining a pressure within the cooling loop and, in response to the pressure increasing above a predetermined leak test value; controlling the trace gas valve to close; After a predetermined time, it is determined whether the pressure in the cooling loop has dropped by more than a predetermined leak test amount, and if not, controlling an exhaust valve to open so that the trace gas is exhausted from the cooling loop; determining a pressure in the cooling loop and, in response to the pressure dropping below a predetermined exhaust value, controlling the exhaust valve to close; determining a pressure in the cooling loop and, in response to the pressure increasing below a predetermined leakage amount, and generating an indication that the cooling loop is properly connected to the refrigeration system.

[0037] A fifth aspect provides a computer program product arranged, when executed by a processor, to control the processor to perform a method according to the third or fourth aspect.

[0038] Further particular and preferred aspects are set out in the independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims as appropriate or in combinations other than those explicitly set out in the claims.

[0039] Where features of a device are described as operable to provide a certain functionality, this should be understood to include features of a device that provide that functionality or that are adapted or configured to provide that functionality.

[0040] Embodiments of the present invention are further described below with reference to the accompanying drawings. [Brief explanation of the drawings]

[0041] [Figure 1] 1 shows a refrigeration system according to a first embodiment. [Figure 2] 2 shows a refrigeration system according to a second embodiment. [Figure 3] 1 shows a flow diagram illustrating method steps for safely disconnecting a cooling loop. [Figure 4] 2 shows schematically the method steps for connecting a cooling loop. DETAILED DESCRIPTION OF THE INVENTION

[0042] Before describing the embodiments in detail, an overview will be given first.

[0043] Embodiments provide a means for venting the chiller or loop and connected piping so that the chiller can be disconnected from the refrigeration system without refrigerant leakage. Embodiments also provide a method for leak checking the chiller connections and piping upon reconnection or initial connection of the chiller to the refrigeration system.

[0044] The valves described below can be any type of standard or custom valve, such as solenoid valves, pneumatic valves, servomotor controlled valves, proportional control valves, etc. Instead of using multiple valves as described below, a valve manifold with multiple flow path configurations can be used. Manifolds help reduce the number of individual valves required. Valves can be of NO (normally open) or NC (normally closed) type. Valves are automatically controlled to open and close by a control circuit.

[0045] The pressure sensing device can be a vacuum gauge, an electronic pressure measurement device (pressure transducer, diode, etc.), which can be a standard or custom type.

[0046] The operating logic is controlled and operated by a controller, which can be of standard or custom type, including but not limited to PID, PLC, and microcontroller types.

[0047] FIG. 1 illustrates a refrigeration system 30 with an automatic control system according to one embodiment. The refrigeration system is in a semiconductor processing apparatus and is connected to a cooling loop 20 that can be used, for example, to cool a chuck that supports a wafer. Because refrigerant is supplied directly from the refrigeration system 30 to the cooling loop 20, care must be taken to prevent refrigerant leakage if the refrigeration system 30 needs to be disconnected from the cooling loop 20. An automatic control system is provided to assist in this process. The automatic control system includes an automatic control valve, which in this embodiment: entrance Valve 1, Exit Valve 3 and a further valve 6 at the compressor end of the return path to isolate the return path from the compressor 10. In this embodiment there is also a bypass line with an automatically controlled valve 8 to supply warmer refrigerant to the supply path. There is also a trace gas source 15 to supply trace gas to the cooling loop 20 during leak testing on connection of the cooling loop to the device, the connection or isolation of this source being controlled by valve 2.

[0048] There is a refrigerant recovery line or zero line loss line which allows refrigerant to be recovered from the cooling loop before disconnection and has a valve 4 which connects or disconnects this line from the cooling loop. There is also a valve 5 which connects the cooling loop via an exhaust pump which allows trace gas to be evacuated from the cooling loop once the leak test is complete. This line has a pressure gauge P2 which can be used to detect if valve 4 is leaking or not closed in case the zero line loss line needs to be disconnected from the cooling loop.

[0049] There is also a pressure gauge P1 for sensing the pressure of the gas in the control loop, which can be used to determine successful venting or further leak testing. The process for preparing for connection and disconnection is controlled by a control circuit 40 which includes a user input 42 and a user output, such as a user display (not shown). The user input allows the user to initiate the connection or disconnection process. The output allows the user to receive an indication when the process has been successfully completed and the connection or disconnection can be performed.

[0050] In addition to the components detailed above (which are related to the control system), there are other components of the refrigeration system, which depend on the type of refrigeration system and may include a heat exchanger between the return path and the supply path.

[0051] The refrigeration system 30 can be of any type, including, but not limited to, systems operating on the vapor compression cycle (Joule-Thompson), GM cycle, or Stirling cycle. The chiller or loop 20 is directly connected to the refrigeration system 30 so that the refrigerant circulates directly through the chiller. In this configuration, the chiller and refrigeration system form a sealed, leak-tight system. The chiller may need to be disconnected from the refrigeration system for various reasons, such as scheduled maintenance or the installation of another chiller. In this case, it is essential to evacuate substantially all of the refrigerant from the chiller and associated piping. The following steps describe one embodiment of how to do this (see Figure 1). 1. Turn off the compressor. 2. Close valves 8, 1, 3, and 6. 3. Ensure valves 2 and 5 are closed. 4. Open valve 4. 5. Turn on the compressor. This will exhaust the refrigerant from the cooling device and piping and move it to the high-pressure side of the compressor. 6. When the pressure at P1 reaches a preset value, the compressor is turned off. 7. Close valve 4. 8. Wait for a specified time and check whether the pressure at P1 increases. 9. If the pressure at P1 does not rise above a predetermined value and / or the rate at which the pressure rises is not faster than a predetermined rate, disconnect the chiller from the refrigeration system.

[0052] If the compressor used above is of very high capacity, methods such as cylinder unloading, VFD (variable frequency drive) control, etc. can be used to meter the pump capacity as needed.

[0053] To reconnect the cooling device to the refrigeration system: 1. Ensure valves 1, 2, 3, 4, 5, 6, and 8 are closed. 2. Connect the cooling device to the refrigerant piping. 3. Open valve 2 to introduce HP trace gas into the cooling system and piping. Pressurize the cooling system to the specified pressure. 4. Close valve 2. At predetermined time intervals, check the pressure drop and rate of pressure drop at P1. 5. If the pressure drop and / or the rate of pressure drop is lower than a predetermined value, open valve 5. 6. Apply vacuum to the cooling system and associated piping until P1 indicates the required vacuum. 7. Close valve 5. 8. Check the pressure rise and rate of pressure rise of P1 at predetermined time intervals. 9. If the pressure rise and / or rate of pressure rise is within a predetermined range, the process is complete.

[0054] The refrigeration system can now be turned on and refrigerant can be safely introduced into the chiller.

[0055] 2 shows an alternative embodiment in which there is an additional pump 18 and buffer tank 19 on the zero line loss line or refrigerant recovery path. There is also a valve 7 at the end of the zero line loss line which serves to isolate it from the compressor and return line. There is also a pressure sensor P2 to sense the pressure in the zero line loss line.

[0056] In this alternative embodiment, a dedicated pump 18 is used to evacuate the cooling loop prior to disconnection, with the refrigerant collecting in tank 19. This is useful when the compressor on the system is too large for this operation or is unsuitable due to suction pressure limitations, or when there are multiple compressors on the system. Upon reconnection, valve 7 is opened to return the recovered refrigerant to the refrigeration system and then closed before starting the refrigeration system. As with the embodiment of FIG. 1, the preparation process for connection and disconnection is controlled by control circuitry 40, which includes a user input 42 and a user display (not shown). The user input allows the user to initiate the connection or disconnection process. The display allows the user to receive an indication when the process has been successfully completed and the connection or disconnection is ready to proceed.

[0057] In this embodiment, the sequence of operations to disconnect the cooling device is as follows (see FIG. 2). 1. Turn off the compressor. 2. Close valves 8, 1, 3, and 6. 3. Ensure valves 2 and 5 are closed. 4. Open valve 4. 5. Turn on the vacuum pump and evacuate the refrigerant in the cooling device and related piping to the steam tank and related piping. 6. When the pressure in the cooling system reaches the predetermined vacuum level indicated by pressure gauge P1, turn off the vacuum pump. 7. Close valve 4 and wait for a specified time to check whether the pressure at P1 increases. 8. If the pressure at P1 does not rise above a predetermined value and / or the rate of pressure rise is not faster than a predetermined rate, the chiller can be disconnected from the refrigeration system.

[0058] To reconnect the cooling device to the refrigeration system: 1. Ensure valves 1, 2, 3, 4, 5, 6, 7, and 8 are closed. 2. Connect the cooling device to the refrigerant piping. 3. Open valve 2 to introduce HP trace gas into the cooling system and piping. Pressurize the cooling system to the specified pressure. 4. Close valve 2. Check the pressure drop and rate of pressure drop at P1 at predetermined time intervals. 5. If the pressure drop and / or the rate of pressure drop is lower than a predetermined value, open valve 5. 6. Apply vacuum to the cooling system and associated piping until P1 indicates the required vacuum. 7. Close valve 5. 8. Check the pressure rise and rate of pressure rise of P1 at predetermined time intervals. 9. If the pressure rise and / or pressure rise rate is within a predetermined range, start the refrigeration system in standby mode. 10. Open valve 7. When the pressure value of P2 reaches the predetermined value, close valve 7. This completes the reconnection process.

[0059] The above are just two of many possible configurations and operating sequences for this service automation. The final engineered solution may have multiple configurations and may have more components or other devices such as valves (check valves, pressure relief valves, manual on / off valves) to ensure redundancy for proper operation, reliability, and safety.

[0060] 3 illustrates steps in a method for isolating a cooling loop and a refrigeration system according to one embodiment. In response to a user-inputted disconnect command in step S10, the control circuit turns off the compressor 10 in step S20. Next, in step D5, it is determined whether the inlet and outlet valves are closed, and if not, the control circuit sends a signal to close the valves in step S30. Once they are closed, it is determined in step D15 whether the refrigerant valves are open, and if not, the control circuit sends a command to open the refrigerant valves in step S40.

[0061] The control circuit then activates a pump in step S50 to pump refrigerant along the refrigerant return path, which may be the compressor of the refrigeration system as in the embodiment of FIG. 1 or a dedicated pump on the refrigerant return line as in the embodiment of FIG. 2.

[0062] Next, pressure sensor P1 determines the pressure in the cooling loop in step D25, and if it is below a threshold, the control circuit controls the pump to turn off in step S60. Next, the control circuit controls the refrigerant recovery valve to close in step S70, and determines whether a predetermined time has elapsed in step D35. If the predetermined time has elapsed, the control circuit determines the pressure rise in the vented cooling loop. If the pressure in the cooling loop rises at a rate greater than a predetermined set point, this indicates a leak, and a warning is displayed to the user. If the pressure rise is not too great, the system is effectively isolated from the refrigeration system, and an indication is output in step S80 indicating that the cooling loop can be safely disconnected from the refrigeration system.

[0063] FIG. 4 illustrates a method for connecting a cooling loop according to one embodiment. In step S100, a connection command is received from a user via user input 42. In response, in step D105, it is determined whether the inlet valve, outlet valve, exhaust valve, and refrigerant recovery valve are closed. If not, in step S110, any valves determined to be open are closed. Once all of these valves are closed in step S120, the trace gas valve is opened to connect the trace gas source to the cooling loop. In step D115, the pressure in the cooling loop is determined by pressure sensor P1. If it is equal to or greater than a predetermined value, in step D130, the trace gas valve is closed and the trace gas source is isolated from the cooling loop. Once it is determined in step D125 that a predetermined time has elapsed, it is determined in step D135 whether the cooling loop pressure has dropped by more than a threshold value. If the rate of pressure drop is greater than the threshold value, this indicates a leak, and a warning is output in step S170. If the rate of pressure drop does not exceed a threshold, then in step S140, the exhaust valve is opened and the exhaust pump can be used to exhaust the trace gas from the cooling loop. Next, in step D145, it is determined whether the pressure in the cooling loop is below a predetermined exhaust value. If so, then in step S150, the exhaust valve is closed. Next, in step D155, it is determined whether the pressure in the cooling loop has risen excessively, which would indicate a leak. If not, then in step S160, an indication is output that the connections are correct and the refrigeration system can be started. If the pressure is found to have risen more than a predetermined amount, then in step S17, a warning is output indicating a leak in the system.

[0064] Although exemplary embodiments of the present invention are disclosed in detail herein with reference to the accompanying drawings, it should be understood that the invention is not limited to the precise embodiments, and that various changes and modifications may result by those skilled in the art without departing from the scope of the present invention as defined by the appended claims and their equivalents. [Explanation of symbols]

[0065] 1 entrance valve 2 Trace Gas Valves 3 Exit valve 4 Refrigerant recovery path valve 5 Exhaust valve 6 More Valves 8 Bypass Line Valve 10 Compressor 15 Trace gas source 18 Buffer Volume 19 Dedicated pump 20 Cooling Loop 30 Refrigeration System 40 Control circuit 42 User Input P1, P2 pressure sensors

Claims

1. A control system for controlling the flow of coolant between a refrigeration system (30) and a cooling loop (20) in a semiconductor processing chamber, the control system controlling the leakage of coolant when the refrigeration system is connected to or disconnected from the cooling loop; an inlet valve configured to selectively isolate or connect a supply path for supplying refrigerant from the refrigeration system to an inlet of the cooling loop; an outlet valve (3) configured to selectively isolate or connect the outlet of the cooling loop to a return path for returning refrigerant to the refrigeration system; a refrigerant recovery valve (4) configured to selectively disconnect or connect the cooling loop to a refrigerant recovery path for recovering a refrigerant from the cooling loop; a pressure sensor for determining the pressure of the refrigerant in the cooling loop; an input for receiving disconnect and connect commands for the cooling loop; a control circuit configured to receive the signal from the pressure sensor and the command from the input and to generate control signals in response thereto for controlling the opening and closing of the inlet valve, the outlet valve, and the refrigerant recovery valve; Equipped with In response to receiving a command to disconnect the cooling loop, the control circuit (40) Controlling the compressor (10) of the refrigeration system to off; Controlling the inlet valve and the outlet valve to close; Controlling the refrigerant recovery valve to open; activating a pump (10) to pump refrigerant from the cooling loop along the refrigerant recovery path toward the refrigeration system; determining a pressure in the cooling loop from the pressure sensor and, in response to the pressure being below a predetermined exhaust value; Controlling the pump to off; Controlling the refrigerant recovery valve to close; determining whether the pressure in the cooling loop has increased by more than a predetermined amount after a predetermined time, and if not, generating an indication that the cooling loop may be safely disconnected from the refrigeration system. It is configured as follows: The pump includes the compressor (10), the control system further comprising a pump configured to pump refrigerant from the cooling loop along the refrigerant return path; The control system further comprises a buffer volume (18) provided on the refrigerant recovery path and a further valve (6) configured to selectively isolate or connect the refrigerant recovery path and the compressor, the control circuit (40) being configured to control the further valve to close before operating the pump, such that, upon operation, the pump pumps the refrigerant from the cooling loop to the buffer volume.

2. 2. The control system of claim 1, further comprising a return path valve configured to selectively isolate or connect the return path from the compressor, and wherein the control circuit is configured to control the return path valve to close when controlling the inlet valve and the outlet valve to close.

3. 3. The control system of claim 1, further comprising a bypass valve configured to selectively block or connect a warmer refrigerant bypass path for supplying warmer refrigerant from the compressor, and wherein the control circuit is configured to control the bypass valve to close when controlling the inlet valve and the outlet valve to close.

4. 4. The control system of claim 1, wherein the control system comprises a trace gas source and a trace gas valve configured to selectively isolate or connect the trace gas source from the cooling loop, and the control circuit is configured to control the trace gas valve.

5. 5. The control system of claim 1, wherein the control system comprises an exhaust valve that selectively isolates or connects the cooling loop to a pump, and the control circuit is configured to control the exhaust valve.

6. The control system, in response to receiving a command to connect a cooling loop, Controlling the inlet valve, the outlet valve, the refrigerant recovery valve, and the exhaust valve to close; controlling the trace gas valve to open so that trace gas from the trace gas source flows into the cooling loop; determining a pressure within the cooling loop and, in response to the pressure increasing above a predetermined leak test value, controlling the trace gas valve to close; determining whether the pressure in the cooling loop has dropped by more than a predetermined leak test amount after a predetermined time; and if not, controlling the exhaust valve to open so that trace gas is exhausted from the cooling loop; determining a pressure within the cooling loop and, in response to the pressure dropping below a predetermined exhaust value, Controlling the exhaust valve to close; determining a pressure within the cooling loop and, in response to the pressure rising below a predetermined leakage rate, indicating that the cooling loop is properly connected to the refrigeration system; 6. A control system according to claims 4 and 5, configured to:

7. 7. The control system of claim 6, wherein the control system is configured to open the further valve in response to an indication that the cooling loop is properly connected to the refrigeration system, and to close the further valve after a predetermined time before starting the refrigeration system.

8. The control system, in response to an indication of starting the refrigeration system, controlling the refrigerant recovery valve, the trace gas valve, and the exhaust valve to close; Controlling the inlet valve and the outlet valve to open; operating the compressor; 8. The control system according to claim 6 or 7, configured as follows:

9. 1. A refrigeration system for supplying refrigerant to a cooling loop in a semiconductor processing chamber, comprising: A compressor; a refrigerant supply path for supplying refrigerant from the compressor to the cooling loop; a refrigerant return path for receiving refrigerant from the cooling loop and returning the refrigerant to the compressor; at least one heat exchanger for exchanging heat between the refrigerant supply path and the refrigerant return path; A control system according to any one of claims 1 to 8; A refrigeration system comprising:

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