Load port and control method

Abstract

The present invention provides a load port and control method that can reliably discharge residual gas from the gas supply path that supplies gas to the FOUP. [Solution] The load port of the present disclosure comprises a mounting base on which a container for housing substrates is placed, and a gas supply device for supplying and discharging gas into the container. The gas supply device includes a gas supply passage, the first end of which is connected to a gas supply source and the second end of which is arranged to be connectable to a container placed on the mounting base; a gas discharge passage, which is arranged to be connectable to the container and discharges gas from inside the container; a flow control device provided in the gas supply passage for controlling the flow rate of gas supplied to the container; an upstream valve provided on the upstream side of the flow control device in the gas supply passage, a downstream valve provided on the downstream side, a connecting passage connecting the gas supply passage and the gas discharge passage, and a relay valve located in the connecting passage. The connecting passage is connected between the upstream valve and the downstream valve of the gas supply passage.

Description

Technical Field

[0001] The present disclosure relates to a load port and a control method.

Background Art

[0002] Substrates such as semiconductor wafers to be processed in a semiconductor manufacturing apparatus are accommodated in a plurality in a container called a FOUP (Front Opening Unified Pod) and transported between semiconductor manufacturing apparatuses. The substrate is placed and accommodated on the slot of the FOUP, and is taken in and out by a transfer arm in the semiconductor manufacturing apparatus through an opening provided in the FOUP. The inside of the FOUP may be filled with a processing gas such as a clean gas or an inert gas in order to prevent, for example, deterioration of the substrate due to oxidation or moisture, or to suppress particle adhesion to the substrate.

[0003] For example, the load port of Patent Document 1 includes a supply path 61 that supplies nitrogen gas to a purge nozzle 37 connected to a supply port, and the supply path 61 is connected to a supply source 60 of nitrogen gas for bottom purge processing. At a predetermined location of the supply path 61, an MFC61a (Mass Flow Controller) that measures and controls the flow rate of the supply path 61, which is a gas flow path, and a supply valve 61b capable of changing the gas supply amount per unit time are provided.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When performing bottom purging, if there is residual gas in the supply path, the residual gas will mix with the gas supplied during bottom purging. This can unintentionally increase the gas supply flow rate per unit time during the initial stages of bottom purging, and also increase the supply pressure. This can lead to problems such as substrate lifting within the FOUP and particle scattering.

[0006] This disclosure aims to provide a load port and control method that can reliably discharge residual gas from a gas supply channel that supplies gas into a FOUP. [Means for solving the problem]

[0007] To solve the above problems, the first embodiment is a load port comprising a mounting base on which a container for housing substrates is placed, and a gas supply device for supplying gas into the container and discharging the gas from the container, wherein the gas supply device comprises a gas supply path having a first end connected to a gas supply source and a second end arranged to be connectable to the container placed on the mounting base, a gas discharge path arranged to be connectable to the container placed on the mounting base and for discharging the gas from the container, a flow rate control device provided in the gas supply path for controlling the flow rate of the gas supplied to the container, an upstream valve provided on the upstream side of the flow rate control device in the gas supply path, a downstream valve provided on the downstream side of the flow rate control device in the gas supply path, a connecting path connecting the gas supply path and the gas discharge path, and a relay valve arranged in the connecting path, wherein the connecting path is connected between the upstream valve and the downstream valve of the gas supply path.

[0008] A second embodiment is a load port according to the first embodiment, further comprising a control unit that controls the operation of each part, wherein the control unit opens the relay valve while the upstream valve and the downstream valve are closed, and then closes the relay valve and opens the upstream valve and the downstream valve.

[0009] A third embodiment is a load port according to the second embodiment, wherein the control unit sets the time for opening the relay valve based on the flow volume between the upstream valve, the downstream valve, and the relay valve.

[0010] A fourth embodiment is a load port according to the second embodiment, further comprising pressure measuring means between the upstream valve and the downstream valve, wherein the control unit opens the intermediate valve and then closes the intermediate valve based on the pressure value measured by the pressure measuring means.

[0011] A fifth aspect is a method for controlling the load port according to the first aspect, wherein the relay valve is opened while the upstream valve and the downstream valve are closed, and then the relay valve is closed and the upstream valve and the downstream valve are opened.

[0012] The sixth aspect is a control method according to the fifth aspect, wherein the time for opening the relay valve is set based on the flow volume between the upstream valve, the downstream valve, and the relay valve.

[0013] The seventh aspect is a control method according to the fifth aspect, wherein after opening the relay valve, the relay valve is closed based on the pressure value between the upstream valve and the downstream valve. [Effects of the Invention]

[0014] According to this disclosure, it is possible to provide a load port and control method that can reliably discharge residual gas from a gas supply path that supplies gas into a FOUP. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic perspective view of a load port according to one embodiment of the present disclosure. [Figure 2] Figure 1 is a schematic side view showing the load port without the FOUP installed. [Figure 3]It is a schematic side view showing a state where a FOUP is placed on the load port of FIG. 1 and a gas supply nozzle is connected. [Figure 4] It is a schematic diagram showing a piping configuration in the load port of FIG. 1. [Figure 5] It is a graph showing an example of a problem in the background art of the present disclosure. [Figure 6] It is a block diagram showing a functional configuration of a load port system including the load port of FIG. 1. [Figure 7] It is a block diagram showing a modified example of a functional configuration of a load port system including the load port of FIG. 1. [Figure 8] It is a flowchart showing a control method for a load port according to an embodiment of the present disclosure. [Figure 9] It is a flowchart showing a control method for zero point adjustment according to an embodiment of the present disclosure.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments for carrying out the present disclosure (hereinafter simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an exemplification for explaining the present disclosure and is not intended to limit the present disclosure to the following contents. The present disclosure can be appropriately modified and implemented within the scope of its gist. In the drawings, the same elements are denoted by the same reference numerals, and redundant explanations are omitted. Also, the positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios.

[0017] <Load Port> As shown in FIGS. 1 and 3, the load port 1 of the present embodiment includes a mounting table 20 for mounting the FOUP 10, a gas supply device 30 for supplying the gas G into the FOUP 10 and discharging the gas G in the FOUP 10, and a control unit 50 for controlling the operations of each part. The gas supply device 30 includes a gas supply passage 34 having an upstream end 31 connected to a gas supply source 32 and a downstream end 33 arranged to be connectable to the FOUP 10. The downstream end 33 is connected to a gas supply nozzle 40 provided on the mounting table 20. Further, the gas supply device 30 includes a gas discharge passage 74 arranged to be connectable to the FOUP 10 and discharging the gas in the FOUP 10. The gas supply passage 34 and the gas discharge passage 74 are connected via a connection passage 75. The connection passage 75 has a relay valve 76. When the relay valve 76 is open, the gas supply passage 34 and the gas discharge passage 74 are connected and the gas G flows through. When the relay valve 76 is closed, the flow of the gas G is blocked.

[0018] The gas supply passage 34 has a mass flow controller 35 for controlling the flow rate of the gas G supplied to the FOUP 10, an upstream valve 36 provided upstream of the mass flow controller 35, and a downstream valve 37 provided downstream of the mass flow controller 35. The connection passage 75 is arranged between the upstream valve 36 and the downstream valve 37. Note that the connection passage 75 may be arranged upstream or downstream of the mass flow controller 35.

[0019] Note that the FOUP 10 is an example of a "container" according to the technology of the present disclosure, and the mass flow controller 35 is an example of a "flow rate control device" according to the technology of the present disclosure. Further, the upstream end 31 is an example of a "first end" according to the technology of the present disclosure, and the downstream end 33 is an example of a "second end" according to the technology of the present disclosure. The gas supply source 32 is an example according to the technology of the present disclosure and is provided to be connectable via a pipe and a connection joint connected to an external gas supply facility (not shown) for supplying gas.

[0020] (Container) As shown in Figures 1 and 3, the FOUP 10 comprises a main body 11 having an opening 12 and a lid 13. The FOUP 10 can accommodate multiple substrates W by placing them on the slot with their surfaces facing upward. The FOUP 10 is provided with an opening 12, which is sealed by the lid 13. The FOUP 10, sealed by the lid 13, is transported by a transport device such as an OHT (Overhead Hoist Transport).

[0021] (Platform) As shown in Figure 1, the mounting base 20 includes a dock plate 21 on which the FOUP 10 containing the substrate W is placed. The dock plate 21 is provided with support pins 22 that support the FOUP 10 from below. The mounting base 20 has a built-in moving mechanism (not shown) that is incorporated into the base 23 and moves the dock plate 21 horizontally (in the X-axis direction in Figure 1). For example, the FOUP 10 transported by a transport device such as an OHT is placed on the dock plate 21 which is waiting on the positive X-axis side, and the dock plate 21 moves toward the plate 60 side (negative X-axis direction) and is attached to the port door 62.

[0022] Furthermore, as shown in Figure 1, a plate 60 extending vertically upward (positive Z-axis direction) is installed on the side end of the base 23 of the mounting table 20. The plate 60 constitutes a connection between the load port 1 and a substrate transport device (e.g., Equipment Front End Module (not shown)) that transfers the substrate W to a process device that performs various processes on the substrate W, and also serves as a partition between the processing area and the outside. The plate 60 has an opening 64 in the region extending upward from the base 23, and when the dock plate 21 moves toward the plate 60 and the FOUP 10 and the plate 60 come into contact, the substrate W is inserted into and removed from this opening 64.

[0023] (Gas supply device) Next, the gas supply device 30 of the load port 1 of this disclosure will be described with reference to Figures 3 and 4.

[0024] As shown in Figure 3, the load port 1 is equipped with a gas supply device 30. The gas supply device 30 includes a gas supply source 32 and a gas supply passage 34 whose upstream end 31 is connected to the gas supply source 32 and whose downstream end 33 is connected to a gas supply nozzle 40, which will be described later. The gas supply device 30 also includes a gas discharge passage 74 for discharging gas from within the FOUP 10, a connecting passage 75 connecting the gas supply passage 34 and the gas discharge passage 74, and a relay valve 76 provided in the connecting passage 75.

[0025] (Gas supply lines) The gas supply passage 34 includes a mass flow controller 35 that controls the flow rate of gas G supplied to the FOUP 10, an upstream valve 36 provided upstream of the mass flow controller 35, and a downstream valve 37 provided downstream of the mass flow controller 35. The gas supply device 30 is also equipped with a gas supply nozzle 40 at the downstream end 33 of the gas supply passage 34 that contacts the bottom surface of the FOUP 10 to supply gas G.

[0026] The gas supply source 32 can be any gas that supplies an inert gas such as N2 or a clean gas, and the type of gas is determined by the film formed on the substrate W housed in the FOUP 10 and the content of the substrate processing. As shown in Figure 4, the N2 gas from the gas supply source 32 is supplied to the discharge section 41 of the gas supply nozzle 40 via a plurality of piping components.

[0027] The mass flow controller 35 controls the flow rate of gas G flowing through the gas supply passage 34 so that it reaches a set flow rate. The mass flow controller 35 can be any known device; any commercially available device that controls the flow rate of gas is acceptable. As shown in Figure 4, the mass flow controller 35 is positioned between the upstream valve 36 and the downstream valve 37 and controls the flow rate of the entire gas supply device 30.

[0028] According to an embodiment of the present disclosure, an upstream valve 36 and a downstream valve 37 are provided in the gas supply passage 34 with a mass flow controller 35 in between. When each valve is opened, gas G supplied from the gas supply source 32 is discharged from the discharge section 41 of the gas supply nozzle 40. The upstream valve 36 and the downstream valve 37 may be of the same type, or a combination of an air valve and a solenoid valve may be used. In this case, the air valve is connected to an air supply source (not shown) via an air supply passage (not shown), and is in an open state when air is supplied and in a closed state when air is not supplied. The supply of air to the air valve is controlled by a solenoid valve provided in the air supply passage. Air is supplied when current flows through the solenoid valve, and no air is supplied when the current to the solenoid valve is interrupted.

[0029] As shown in Figure 4, in this embodiment, the gas supply passage 34 is connected to three branch passages downstream of the downstream valve 37. Each branch passage of the gas supply passage 34 is further equipped with a flow rate monitor 70, a speed controller 38, and a gas filter 39, in order from upstream. Each branch passage is connected to one of the three discharge sections 41 shown in Figure 1. A pressure monitor 72 is also provided upstream of the upstream valve 36 of the gas supply passage 34.

[0030] Furthermore, in this embodiment, a pressure measuring means 73 can be provided between the upstream valve 36 and the downstream valve 37 of the gas supply passage 34.

[0031] The flow rate monitor 70 monitors the flow rate of gas flowing through the gas supply line 34. By continuously monitoring the gas flow rate downstream of the gas supply line 34, it becomes possible to detect abnormalities in the mass flow controller 35 and leaks. The pressure monitor 72 monitors the pressure of the gas supplied from the gas supply source 32. By continuously monitoring the gas pressure, it is possible to detect abnormalities in the upstream valve 36, the mass flow controller 35, and the downstream valve 37.

[0032] The speed controller 38 adjusts the gas flow rate in each branch line to ensure that the gas flow rate discharged from each gas supply nozzle 40 is uniform. The gas filter 39 is used to improve the cleanliness of the gas discharged into the FOUP 10.

[0033] (Gas discharge channel) As shown in Figure 3, the gas supply device 30 is equipped with a gas discharge passage 74 for discharging gas from inside the FOUP 10. The gas discharge passage 74 is connected to a gas discharge nozzle 42 provided on the mounting base 20. In Figures 1 and 3, the gas G supplied into the FOUP 10 from the gas supply nozzle 40 is discharged from the discharge section 43 of the gas discharge nozzle 42. The gas G discharged from the gas discharge nozzle 42 is then discharged to the outside of the device through the gas discharge passage 74 connected to the gas discharge nozzle 42.

[0034] (connecting path) In this embodiment, the gas supply device 30 is further provided with a connecting passage 75 that connects the gas supply passage 34 and the gas discharge passage 74. On the gas supply passage 34 side, the connecting passage 75 is connected between the upstream valve 36 and the downstream valve 37. In the example shown in Figure 3, the connecting passage 75 is located between the downstream valve 37 and the mass flow controller 35, but the configuration is not limited to this, and it may also be located between the upstream valve 36 and the mass flow controller 35.

[0035] (Relay valve) A relay valve 76 is placed in the aforementioned connection passage 75. The relay valve 76 is a valve that releases the gas in the gas supply passage 34 to the gas discharge passage 74. For example, if residual gas G is present in the gas supply passage 34, the internal pressure of the gas supply passage 34 will be higher than the internal pressure of the gas discharge passage 74. In this case, when the relay valve 76 is opened, the residual gas G present in the gas supply passage 34 will flow to the gas discharge passage 74, and the gas flow will stop when the internal pressures of the gas supply passage 34 and the gas discharge passage 74 become approximately equal.

[0036] According to the configuration of the load port 1 described above, the gas supply passage 34 is provided with an upstream valve 36 and a downstream valve 37, with the mass flow controller 35 in between.

[0037] The configuration of providing an upstream valve 36 and a downstream valve 37 on the upstream and downstream sides of the mass flow controller 35 is important for accurate flow control in the supply of gas G. One reason for installing the upstream valve 36 and downstream valve 37, which consist of solenoid valves, before and after the mass flow controller 35, is zero-point adjustment (zero calibration). This is a very important process for accurate flow control. Because the mass flow controller 35 has a highly sensitive sensor that can detect even minute flow rates, it may misinterpret even slight leaks or disturbances as "gas flowing". Zero-point adjustment is a calibration process that makes the mass flow controller 35 recognize a state where there is no fluid flow and the flow rate is "0". The mass flow controller 35 alone cannot completely shut off the fluid and stop the flow, so during adjustment, minute leaks from upstream may flow into the mass flow controller 35, or backflow due to downstream pressure fluctuations or the flow of residual gas G inside the mass flow controller 35 may occur. To prevent these issues, it is necessary to install solenoid valves before and after the mass flow controller 35 to completely shut off the flow and create a "zero flow rate" state.

[0038] However, if the upstream valve 36 and downstream valve 37 before and after the mass flow controller 35 are completely shut off, there is a possibility that gas G may remain between the upstream valve 36 and the downstream valve 37. The inventors of this disclosure have discovered that when gas G remains between the upstream valve 36 and the downstream valve 37, opening the upstream valve 36 and the downstream valve 37 causes a phenomenon in which the flow rate momentarily exceeds the set flow rate in the initial stage of discharge, as shown in the circled area of ​​Figure 5. This is thought to be because the gas G remaining between the upstream valve 36 and the downstream valve 37 at a predetermined pressure is discharged from the gas supply nozzle 40 together with the gas supplied from the gas supply source 32. When gas exceeding the set flow rate is discharged momentarily in this way, there is a risk that the FOUP 10 and the substrate W inside the FOUP 10 may float up, or particles may be scattered. Therefore, it is necessary to properly discharge the gas G remaining in the gas supply passage 34 before supplying gas G from the gas supply source 32.

[0039] (Gas supply nozzle) Next, the gas supply nozzle 40 will be described with reference to Figures 1 to 3. The gas supply device 30 is equipped with a gas supply nozzle 40 at the downstream end 33 of the gas supply passage 34. The gas supply nozzle 40 has a discharge section 41 and a lifting mechanism 44.

[0040] The discharge section 41 has a hollow gas passage, and a discharge hole (not shown) is formed in the center of the discharge section 41 in a plan view. The gas passage of the discharge section 41 communicates with the gas supply passage 34, causing the gas supplied from the gas supply passage 34 to be discharged from the discharge hole. The discharge hole of the discharge section 41 then contacts the nozzle port on the bottom surface of the FOUP 10, causing the gas to be discharged into the FOUP 10 from the discharge hole.

[0041] As shown in Figures 2 and 3, the discharge section 41 is fixed to the lifting mechanism 44, and the discharge section 41 can be raised and lowered between a lowered position and a ventilation position, as described later, by moving the lifting mechanism 44 vertically up and down. The lifting mechanism 44 can be configured in any way that allows the discharge section 41 to be raised and lowered vertically, and that the gas flow path of the discharge section 41 can be connected to the nozzle port on the bottom surface of the FOUP 10 by bringing the discharge section 41 into contact with the bottom surface of the FOUP 10.

[0042] When the FOUP 10 is not placed on the mounting base 20, the discharge portion 41 of the gas supply nozzle 40 is positioned in the lowered position shown in Figures 1 and 2. Here, the lowered position is the position where the upper end surface of the discharge portion 41 of the gas supply nozzle 40 is at the same height as the surface of the dock plate 21. Note that in this lowered position, the upper end surface of the discharge portion 41 of the gas supply nozzle 40 only needs to be lower than the bottom surface of the FOUP 10, and does not necessarily need to be at the same height as the surface of the dock plate 21. Furthermore, when the FOUP 10 is placed on the mounting base 20 and gas is supplied into the FOUP 10, the discharge portion 41 of the gas supply nozzle 40 is positioned in the ventilation position shown in Figure 3. Here, the ventilation position is the position where the upper end surface of the discharge portion 41 of the gas supply nozzle 40 abuts against the bottom surface of the FOUP 10, and the nozzle port (not shown) of the FOUP 10 communicates with the discharge hole of the discharge portion 41.

[0043] (Gas discharge nozzle) In this embodiment, the gas supply device 30 is equipped with a gas discharge nozzle 42 at the end of the gas discharge passage 74. The gas discharge nozzle 42 has a discharge section 43. The gas discharge nozzle 42 can have the same configuration as the gas supply nozzle 40, and the discharge hole (not shown) of the discharge section 43 contacts the nozzle port on the bottom surface of the FOUP 10 to discharge gas from inside the FOUP 10. In the example shown in Figure 3, the discharge section 43 of the gas discharge nozzle 42 is fixed to the lifting mechanism 44 of the gas supply nozzle 40 and moves up and down together with the discharge section 41 of the gas supply nozzle 40. However, the discharge section 43 of the gas discharge nozzle 42 may be fixed to a separate lifting mechanism (not shown) from the gas supply nozzle 40.

[0044] (Control Unit) Next, the control unit 50 of the load port 1 of this disclosure will be described with reference to Figures 3 and 6. As shown in Figure 6, the load port 1 of this disclosure constitutes a load port system 100 by electrically connecting the control unit 50, the flow rate adjustment unit 55, and the monitoring unit 56 to a higher-level control unit 59.

[0045] As shown in Figure 6, the control unit 50 is electrically connected to the relay valve 76, the upstream valve 36, the downstream valve 37, and the lifting mechanism 44 of the gas supply nozzle 40.

[0046] As shown in Figure 3, the control unit 50 includes a controller 51 that receives various control programs and input data from input devices (not shown) to control the operation of each part of the load port 1, and a storage unit 52 that receives various control programs and input data from input devices from the controller 51 and stores them as needed.

[0047] The controller 51 is composed of, for example, a CPU (Central Processing Unit), memory such as ROM (Read Only Memory) and RAM (Random Access Memory), and controls the operation of each part by executing a predetermined program. The CPU controls each component and performs various calculations according to the program recorded in the ROM or storage unit 52.

[0048] The storage unit 52 can consist of a storage medium such as a hard disk drive, compact disk, flash memory, flexible disk, or memory card. A control program is stored in these storage media, and the control program is installed in the control unit 50 and executed by the controller 51.

[0049] As shown in Figure 6, the control unit 50 includes a valve control unit 53, a nozzle control unit 54, and a timing control means 57 as its functions.

[0050] The valve control unit 53 controls the opening and closing operations of the relay valve 76, the upstream valve 36, and the downstream valve 37. For example, the opening timing of the upstream valve 36 and the downstream valve 37 can be set to be simultaneous, staggered at different times, or the opening order can be specified. In this embodiment, the relay valve 76 and the upstream valve 36 and the downstream valve 37 operate exclusively. That is, when the relay valve 76 is open, the upstream valve 36 and the downstream valve 37 are closed, and after the relay valve 76 is closed, the upstream valve 36 and the downstream valve 37 become open.

[0051] The nozzle control unit 54 controls the raising and lowering operation of the lifting mechanism 44 that fixes the gas supply nozzle 40 and the gas discharge nozzle 42. The nozzle control unit 54 may coordinate the raising and lowering timing of the lifting mechanism 44 with the operation of other parts. For example, the lifting mechanism 44 can be raised and lowered in conjunction with the opening operation of the upstream valve 36 and the downstream valve 37 controlled by the valve control unit 53.

[0052] The timing control means 57, for example, consists of an internal clock and a timer (time setting means), and can count the time interval for opening the relay valve 76. Specifically, the timing control means 57 may determine the time for opening the relay valve 76 according to the amount of residual gas G in the gas supply path 34, particularly the amount of residual gas G between the upstream valve 36 and the downstream valve 37. In this embodiment, the amount of residual gas G between the upstream valve 36 and the downstream valve 37 is determined based on the flow path volume between the upstream valve 36, the downstream valve 37, and the relay valve 76. That is, the amount of residual gas G is determined based on the flow path volume, which is the sum of the flow path volume between the upstream valve 36 and the downstream valve 37 of the gas supply path 34 and the flow path volume between the connection point of the connecting path 75 and the gas supply path 34 and the relay valve 76. Therefore, the control unit 50 sets the time for opening the relay valve 76 based on the flow path volume between the upstream valve 36, the downstream valve 37, and the relay valve 76, and transmits a control signal to the timing control means 57.

[0053] With the above configuration, valve control can be achieved using the internal clock of the control unit 50 without requiring an external timer circuit, thereby simultaneously achieving system simplification and cost reduction.

[0054] (Flow rate adjustment part) The flow rate adjustment unit 55 controls the operation of the mass flow controller 35. The mass flow controller 35 is a device that measures the mass flow rate of a fluid and controls it to a set flow rate, and the flow rate adjustment unit 55 controls the mass flow controller 35 so that the gas G flowing through the gas supply passage 34 reaches the set flow rate. The mass flow controller 35 in this embodiment may be a commercially available device.

[0055] (Monitoring Department) The monitoring unit 56 controls a flow rate monitor 70 that monitors the flow rate of gas G flowing through the gas supply line 34, and a pressure monitor 72 that monitors the pressure in the gas supply line 34. The monitoring unit 56 may also control other monitors, such as a temperature monitor or a flow velocity monitor, in addition to these monitors. The monitoring unit 56 obtains flow rate and pressure information from the flow rate monitor 70 and the pressure monitor 72, and monitors whether the flow rate and pressure are within, for example, a preset threshold range. If the flow rate and pressure are not within, for example, a preset threshold range, the monitoring unit 56 may determine that an abnormality has occurred and issue an alarm. Furthermore, the monitoring unit 56 may accumulate data on the obtained flow rate and pressure information and predict the occurrence of abnormalities.

[0056] (Higher-level control unit) The upper control unit 59 is electrically connected to the control unit 50, the flow rate adjustment unit 55, and the monitoring unit 56. The upper control unit 59 commands the valve control unit 53 to close the open upstream valve 36 and downstream valve 37. In this embodiment, the upper control unit 59 controls the valve control unit 53 to close the upstream valve 36 and downstream valve 37 simultaneously after the valve control unit 53 has opened the downstream valve 37 and the upstream valve 36 simultaneously to supply gas G into the FOUP 10.

[0057] <Control Method> The operation of load port 1 in the configuration described above will be explained in detail with reference to Figures 8 and 9.

[0058] In this embodiment, an OHT (not shown) transports the FOUP 10 to the load port 1, and the FOUP 10 is placed on the dock plate 21 (step S101). At this time, the gas supply nozzle 40 is waiting in a lowered position (see Figure 2) where the upper end surface of the nozzle and the surface of the dock plate 21 are at the same height. The FOUP 10 is then handed over to the support pins 22 of the dock plate 21.

[0059] When the control unit 50 detects that the FOUP 10 has been placed on the dock plate 21, it controls the dock plate 21 to move horizontally toward the plate 60. When the FOUP 10 comes into contact with the plate 60 and the port door 62, the port door 62 moves horizontally toward the rear (negative direction in the X-axis direction) while holding the lid 13, opening the opening 64 in the plate 60. Subsequently, the control unit 50 moves the port door 62, which is holding the lid 13, vertically downward (negative direction in the Z-axis direction), lowering the port door 62 to a height where the FOUP 10 opens toward the substrate transport device. Then, the substrates W are removed from the FOUP 10 one or more at a time by a transport robot arm (not shown) inside the substrate transport device, transported to a process device adjacent to the substrate transport device, and after a series of processes are performed in the process device, they are returned to the FOUP 10 again via the substrate transport device.

[0060] The nozzle control unit 54 of the control unit 50 controls the lifting mechanism 44 to raise the gas supply nozzle 40 to the ventilation position (see Figure 3) at either the time before or after the movement of the dock plate 21 (step S201). In this way, the discharge portion 41 of the gas supply nozzle 40 comes into contact with the nozzle port provided on the bottom surface of the FOUP 10. In this embodiment, when the gas supply nozzle 40 is raised, the upstream valve 36 and the downstream valve 37 are closed.

[0061] Next, the valve control unit 53 of the control unit 50 opens the upstream valve 36 and the downstream valve 37 from a closed state by initiating a purge command (step S202).

[0062] By opening the upstream valve 36 and the downstream valve 37, the gas G supplied from the gas supply source 32 flows through the gas supply passage 34 to the gas supply nozzle 40 and is discharged into the FOUP 10 from the discharge section 41.

[0063] After supplying gas G into the FOUP 10, the upper control unit 59 closes the upstream valve 36 and the downstream valve 37 (step S205). At this time, from a safety standpoint, both valves are closed simultaneously, or the downstream valve 37 is closed preferentially. The time for supplying gas G into the FOUP 10 is determined appropriately depending on the type of film formed on the substrate W and the type of process treatment.

[0064] After closing the upstream valve 36 and the downstream valve 37, the nozzle control unit 54 of the control unit 50 drives the lifting mechanism 44 to lower the gas supply nozzle 40 from the ventilation position to the lowered position (step S207).

[0065] Meanwhile, the substrates W inside the FOUP 10 are processed in the process equipment of the substrate processing device, and the substrates W that have finished processing in the process equipment are transported to the FOUP 10 by the substrate transport device. Once all the substrates W that have finished processing in the process equipment are placed inside the FOUP 10, the port door 62 moves vertically upward (positive Z-axis direction) while holding the lid 13. Then, the port door 62 moves horizontally towards the front (positive X-axis direction), and the lid 13 is fitted into the opening 12 of the FOUP 10, sealing the FOUP 10.

[0066] The sealed FOUP 10 is moved away from the plate 60 by the dock plate 21 (positive direction in the X-axis direction) and transported to the next substrate processing device by the OHT (step S102).

[0067] (Zero point adjustment) Next, zero-point adjustment will be explained with reference to Figure 9. In this embodiment, the operation of the load port 1 is performed on the condition that zero-point adjustment is completed, at least for the operation processes in steps S202 and S205. Therefore, if zero-point adjustment is started at any time, each operation process will be temporarily suspended until zero-point adjustment is completed. For example, if zero-point adjustment is started in step S202, the upstream valve 36 and the downstream valve 37 will be closed, and the operation process of S202 will be suspended until zero-point adjustment is completed. After zero-point adjustment is completed, the process will return to S202. Here, zero-point adjustment refers to correcting the output (flow rate value) of the mass flow controller 35 so that it becomes zero.

[0068] In this embodiment, zero-point adjustment of the mass flow controller 35 is performed by controlling the operation of an upstream valve 36 located upstream of the mass flow controller 35 and a downstream valve 37 located downstream of the mass flow controller 35. Specifically, first, when a zero-point adjustment start signal is detected, the upstream valve 36 and the downstream valve 37 are completely shut off (step S301). This stops the fluid flow in the mass flow controller 35. Next, the output of the mass flow controller 35 is checked, and if the output is not zero, it is corrected to become zero (step S302). Thus, zero-point adjustment is completed.

[0069] In this embodiment, after zero-point adjustment is completed, residual gas G remaining between the gas supply passage 34 between the upstream valve 36 and the downstream valve 37 and the intermediate valve 76 at the connection point between the gas supply passage 34 of the connecting passage 75 is discharged to the outside of the device via the connecting passage 75 to the gas discharge passage 74. That is, with the upstream valve 36 and the downstream valve 37 closed, the valve control unit 53 opens the intermediate valve 76 located in the connecting passage 75 to allow the residual gas G to flow to the gas discharge passage 74 (step S303).

[0070] After opening the relay valve 76 for a certain interval, the relay valve 76 is closed (step S304). After the residual gas G is discharged from the gas supply passage 34 in this way, the process returns to step S202, and the upstream valve 36 and the downstream valve 37 are opened.

[0071] (Control of relay valves) After zero-point adjustment is complete, the valve control unit 53 opens the intermediate valve 76 located in the connecting passage 75 for a certain period of time. The opening time of the intermediate valve 76 is preset based on the flow path volume between the upstream valve 36, the downstream valve 37, and the intermediate valve 76. For example, the flow path volume is calculated from the inner diameter and length of the flow path, and a sufficient time (e.g., about 3 to 10 seconds) is set to completely discharge the residual gas.

[0072] This opening time is counted by the timing control means 57. The timing control means 57 has an internal clock generator that operates at a constant frequency (e.g., 20Hz) and measures time intervals by pulses of this internal clock (not shown). First, a reference clock signal is input from the internal clock to a timer (not shown). The timer generates timer interrupt signals at regular intervals by dividing the reference clock signal by a predetermined frequency division ratio. These timer interrupt signals are transmitted to the valve control unit 53 in the control unit 50. Then, the opening control of the relay valve 76 is executed according to a pre-programmed control algorithm.

[0073] It is preferable that the closing operation of the relay valve 76 after opening occurs after a period of time has elapsed for the residual gas G to be discharged. The fixed interval for opening the relay valve 76 may be determined by estimating the amount of residual gas G from the volume of the piping in the gas supply passage 34 and determining it according to that amount of residual gas G. In this embodiment, the amount of residual gas G is estimated based on the flow path volume between the upstream valve, the downstream valve and the relay valve, and the timing control means 57 provided in the control unit 50 is instructed to count based on the time interval set accordingly.

[0074] Here, residual gas G is mainly generated when the upstream valve 36 and the downstream valve 37 are closed simultaneously, and the gas becomes trapped in the piping between the two valves. While it is possible to set a time difference in the closing timing, this raises concerns about a longer cycle time. Furthermore, simultaneous closing is desirable in the case of an emergency shutdown. Therefore, in this embodiment, the valves are closed simultaneously without a time difference.

[0075] The residual gas G remaining in the gas supply passage 34 is naturally discharged using the pressure difference between the gas supply passage 34 and the gas discharge passage 74. Before the discharge of residual gas G, the pressure inside the gas supply passage 34 is higher than that of the atmosphere. On the other hand, the pressure inside the gas discharge passage 74 is the same as that of the atmosphere, so due to the physical properties of the gas, it naturally flows from the area of ​​high pressure to the area of ​​low pressure when the relay valve 76 is opened. Since the residual gas G needs to be completely released from the gas supply passage 34, the timing between opening and closing the relay valve 76 is set to be longer.

[0076] The amount of residual gas G to be discharged is determined by the inner pipe diameter of the gas supply passage 34 and the connecting passage 75 (for example, about 9.5 mm (3 / 8 inch)) and the length of the piping in which the residual gas G accumulates. For example, in this embodiment, it is determined by the distance between the upstream valve 36 and the downstream valve 37 of the gas supply passage 34 (about 680 mm) and the distance between the connection point of the connecting passage 75 with the gas supply passage 34 and the intermediate valve 76. The time it takes for the residual gas G to be discharged from the gas supply passage 34 and the connecting passage 75 varies mainly depending on the amount of residual gas G, the pressure difference between the gas supply passage 34 and the gas discharge passage 74, the length of the connecting passage 75, etc.

[0077] As described above, in the load port 1 of this embodiment, the gas supply device 30 that supplies gas G into the FOUP 10 has an upstream valve 36 and a downstream valve 37 in the gas supply passage 34 that connects the gas supply source 32 and the gas supply nozzle 40, with a mass flow controller 35 in between. Between the upstream valve 36 and the downstream valve 37 of the gas supply passage 34, there is a connecting passage 75 with an intermediate valve 76. With this configuration, the gas G remaining in the gas supply passage 34 can be reliably discharged at any timing after zero point adjustment. Furthermore, since the residual gas G is discharged directly without passing through the FOUP 10, discharge can be performed in a shorter time compared to when it is discharged via the FOUP 10, thus shortening the cycle time.

[0078] Furthermore, the valve control unit 53 of the control unit 50 opens the relay valve 76 of the connecting passage 75 while the upstream valve 36 and downstream valve 37 of the gas supply passage 34 are closed, and then closes the relay valve to open the upstream valve 36 and downstream valve 37. In this way, residual gas between the upstream valve 36 and downstream valve 37 is reliably discharged before supplying gas G to the FOUP 10 by opening the upstream valve 36 and downstream valve 37. Therefore, the flow rate of gas G flowing into the gas supply passage 34 can be accurately controlled without being affected by gas G remaining in the gas supply passage 34.

[0079] Furthermore, the control unit 50 sets the time for opening the relay valve 76 based on the flow path volume between the upstream valve 36, the downstream valve 37, and the relay valve 76. In this way, the opening and closing of the relay valve 76 is controlled according to the amount of residual gas G, so that the residual gas G is discharged appropriately. Therefore, it is possible to suppress sudden increases in flow rate when gas G is discharged, and furthermore, it is possible to prevent a decrease in production efficiency due to excessively long time intervals.

[0080] <Variation> Figure 7 shows a modified load port system 200, which is a modified version of the load port system 100 shown in Figure 6 above. Components identical to those in load port system 100 are denoted by the same reference numerals and their descriptions are omitted. The control unit 502 of the modified load port 2 shown in Figure 7 includes a valve control unit 53, a nozzle control unit 54, a flow rate adjustment unit 55, a flow rate monitoring unit 561, and a pressure monitoring unit 58 as its functions. The control unit 502 is also electrically connected to a relay valve 76, an upstream valve 36, a downstream valve 37, a lifting mechanism 44 for the gas supply nozzle 40, a mass flow controller 35, a flow rate monitor 70, a pressure monitor 72, and a pressure measuring means 73.

[0081] The flow rate monitoring unit 561 is electrically connected to the flow rate monitor 70 and controls the operation of the flow rate monitor 70. The control of the flow rate monitor 70 by the flow rate monitoring unit 561 is the same as the control by the monitoring unit 56 described above, so a detailed explanation is omitted.

[0082] The pressure monitoring unit 58 controls the operation of the pressure monitor 72 and the pressure measuring means (e.g., pressure gauge) 73. The control of the pressure monitor 72 by the pressure monitoring unit 58 is the same as the control by the monitoring unit 56 described above, so a detailed explanation is omitted.

[0083] The pressure measuring means 73 is installed between the upstream valve 36 and the downstream valve 37 and monitors the pressure in the gas supply passage 34 in real time. This pressure measuring means 73 monitors the pressure in the gas supply passage 34 between the upstream valve 36 and the downstream valve 37 and accurately detects the presence or absence of residual gas G. For example, if residual gas G is present, the pressure in the gas supply passage 34 will be higher than atmospheric pressure, and if the residual gas G is completely discharged, it will be equal to atmospheric pressure.

[0084] As the pressure measuring means 73, for example, a pressure measuring device such as a semiconductor pressure sensor or a piezoresistive pressure sensor can be used. In terms of measurement accuracy, an accuracy of about ±0.1 kPa relative to atmospheric pressure is sufficient to adequately determine the presence or absence of residual gas.

[0085] After the valve control unit 53 opens the relay valve 76, the pressure monitoring unit 58 compares the measured value (pressure value) obtained from the pressure measuring means 73 with a preset threshold (for example, atmospheric pressure + 0.5 kPa). When the measured value falls below the threshold, the unit determines that the residual gas G has been completely discharged and transmits the determination result to the valve control unit 53. Subsequently, the valve control unit 53 outputs a command to close the relay valve 76. Here, the preset threshold is appropriately set based on the pressure difference between the internal pressure when residual gas G remains and the internal pressure when residual gas G has been discharged, or the actual measured value of the internal pressure.

[0086] Furthermore, the pressure monitoring unit 58 can also record the pressure values ​​collected through monitoring as pressure data in the storage unit 52 and store them as the system's operation history.

[0087] The above method enables control that corresponds to the actual discharge status of residual gas G (measured control) rather than time control (predictive control) using a fixed timer. This allows for valve control at the optimal timing at all times, even with variations in residual gas G discharge time due to differences in pipe length, inner diameter, and environmental conditions, resulting in more precise flow control.

[0088] Furthermore, the functional configuration of the load port system 100 and the functional configuration of the load port system 200 may be combined. That is, the opening and closing timing of the relay valve 76 may be controlled by the timing control means 57, and the pressure inside the gas supply passage 34 between the upstream valve 36 and the downstream valve 37 may be monitored by the pressure measuring means 73. In this case, if the pressure value obtained by the pressure measuring means 73 is not below a threshold value at the time the closing command for the relay valve 76 is output by the timing control means 57, a process is executed to delay the closing timing of the relay valve 76.

[0089] While embodiments of this disclosure have been described above with reference to the attached drawings, this disclosure is not limited to the contents of the embodiments described above, and modifications can be made as appropriate without departing from this disclosure. In other words, all other embodiments, examples, and operational techniques made by those skilled in the art based on these embodiments are, of course, included in the scope of this disclosure.

[0090] In the above embodiment, the timing control means 57 was equipped with an internal clock, but it is not limited to this, and an external clock may also be used.

[0091] Furthermore, the effects described in the above embodiments are descriptive or illustrative, and are not limited to those described in the above embodiments. In other words, the technology relating to this disclosure may produce other effects that would be obvious to a person of ordinary skill in the art of this disclosure from the descriptions in the above embodiments, in addition to or in lieu of the effects described in the above embodiments.

[0092] The control unit 50 in each of the above embodiments may include various processors other than the CPU. Examples of such processors include PLDs (Programmable Logic Devices) such as FPGAs (Field-Programmable Gate Arrays) whose circuit configuration can be changed after manufacturing, and dedicated electrical circuits that are processors with circuit configurations specifically designed to perform specific processing, such as ASICs (Application Specific Integrated Circuits). The control method according to this disclosure may be executed by one of the various processors, or by a combination of two or more processors of the same or different types (for example, multiple FPGAs, and a combination of a CPU and an FPGA). More specifically, the hardware structure of these various processors is an electrical circuit that combines circuit elements such as semiconductor elements.

[0093] Furthermore, the program for executing the control method relating to this disclosure may, but is not limited to, being pre-stored (installed) in the ROM or storage unit 52. The program may be provided in a form recorded on a non-transitory recording medium such as a CD-ROM (Compact Disk Read Only Memory), DVD-ROM (Digital Versatile Disk Read Only Memory), or USB (Universal Serial Bus) memory. Alternatively, the program may be provided in a form that can be downloaded from an external device via a network. [Explanation of symbols]

[0094] 1, 2 Load Ports 10 FOUP 20 mounting platform 30 Gas supply device 34 Gas supply lines 35 Mass Flow Controller 36 Upstream valve 37 Downstream valve 40 Gas supply nozzles 41 Discharge part 42 Gas discharge nozzle 43 Discharge section 50, 502 Control Unit 72 Pressure Monitor 73 Pressure measuring means 74 Gas exhaust channels 75 connecting routes 76 Relay valve 100, 200 load port system

Claims

1. A mounting platform on which a container for housing a circuit board is placed, The system includes a gas supply device that supplies gas into the container and discharges the gas from the container, The aforementioned gas supply device is A gas supply path having a first end connected to a gas supply source and a second end arranged to be connectable to the container placed on the aforementioned stand, A gas discharge passage is provided which is connected to the container placed on the aforementioned mounting base and discharges the gas inside the container, A flow control device provided in the gas supply path for controlling the flow rate of the gas supplied to the container, An upstream valve provided on the upstream side of the flow control device in the gas supply line, A downstream valve provided on the downstream side of the flow control device in the gas supply line, A connecting passage that connects the gas supply passage and the gas discharge passage, The connection path includes a relay valve, The aforementioned connecting passage is connected between the upstream valve and the downstream valve of the gas supply passage. It further includes a control unit that controls the operation of each part, The control unit, A load port characterized by opening the relay valve while the upstream valve and the downstream valve are closed, and then closing the relay valve and opening the upstream valve and the downstream valve.

2. The load port according to claim 1, characterized in that the control unit sets the time for opening the relay valve based on the flow volume between the upstream valve, the downstream valve and the relay valve.

3. A pressure measuring means is further provided between the upstream valve and the downstream valve. The load port according to claim 1, characterized in that the control unit opens the relay valve and then closes the relay valve based on the pressure value measured by the pressure measuring means.

4. A mounting platform on which a container for housing a substrate is placed, The system includes a gas supply device that supplies gas into the container and discharges the gas from the container, The aforementioned gas supply device is A gas supply path having a first end connected to a gas supply source and a second end arranged to be connectable to the container placed on the aforementioned stand, A gas discharge passage is provided which is connected to the container placed on the aforementioned mounting base and discharges the gas inside the container, A flow control device provided in the gas supply path for controlling the flow rate of the gas supplied to the container, An upstream valve provided on the upstream side of the flow control device in the gas supply line, A downstream valve provided on the downstream side of the flow control device in the gas supply line, A connecting passage that connects the gas supply passage and the gas discharge passage, The connection path includes a relay valve, The aforementioned connection path is a control method for a load port connected between the upstream valve and the downstream valve of the gas supply path, A control method characterized by opening the relay valve while the upstream valve and the downstream valve are closed, then closing the relay valve, and opening the upstream valve and the downstream valve.

5. The control method according to claim 4, characterized in that the time for opening the relay valve is set based on the flow volume between the upstream valve, the downstream valve, and the relay valve.

6. The control method according to claim 4, characterized in that after opening the relay valve, the relay valve is closed based on the pressure value between the upstream valve and the downstream valve.

Images