Equipment front end module (EFEM) and method of controlling supply amount of inert gas

Abstract

An equipment front-end module (EFEM) includes: an inert gas supply total setting unit, which sets the total inert gas supply to the frame based on the oxygen concentration inside the frame; a door opening and bottom purging determination unit, which determines for each loading port whether the door of the front open box (FOUP) is open and whether bottom purging is being performed by a bottom purging device; and an inert gas supply amount calculation unit, which, if the determination result of the determination unit is yes, calculates the inert gas supply amount to the frame based on the value obtained by subtracting the bottom purging inert gas supply amount of the bottom purging device of the loading port from the total inert gas supply amount, and controls the inert gas supply amount to the frame according to the inert gas supply amount command value determined based on the calculation result of the calculation unit.

Description

Technical Field

[0001] This invention relates to an EFEM (Equipment Front End Module) for automatic handling of substrates, and in particular to a control system and control method for supplying an inert gas such as nitrogen into the frame that serves as the main body of the EFEM. Prior Technology

[0002] In semiconductor manufacturing processes, substrates are handled in cleanrooms to improve yield and quality. In recent years, a method has been adopted that introduces a "mini-environment" approach to further enhance cleanliness only in a localized area surrounding the substrate, performing processes other than substrate handling. In the mini-environment approach, a portion of the wall of a frame forms a largely enclosed substrate handling space (hereinafter referred to as the "handling space"). A container called a FOUP (Front-Opening Unified Pod) holding the substrate is placed within this highly clean internal space. With the FOUP door (hereinafter referred to as the "FOUP door") pressed against the frame, a load port is provided adjacent to the frame, functioning to open and close the FOUP door.

[0003] The loading port is a device used for loading and unloading substrates between the frame and the FOUP, functioning as an interface between the frame and the FOUP. Furthermore, it is configured such that if the loading port door (hereinafter referred to as the "loading port door") is opened, it can engage with the FOUP door to open and close the FOUP door. Then, a substrate handling robot arranged in the handling space within the frame can remove substrates from the FOUP into the frame, or store substrates from the frame into the FOUP.

[0004] Furthermore, in the semiconductor manufacturing process, in order to properly maintain the atmosphere around the substrate, a storage container called a FOUP is used to store and manage the substrate inside the FOUP. In particular, in recent years, with the advancement of high integration of components and miniaturization of circuits, it is required to maintain a high degree of cleanliness around the substrate to prevent particles and moisture from adhering to the substrate surface. Therefore, in order to prevent changes in surface properties such as oxidation of the substrate surface, a process is also performed where nitrogen is filled into the FOUP to create a nitrogen atmosphere as an inert gas or a vacuum state around the substrate (purging process).

[0005] Furthermore, an EFEM constructed by filling the frame with nitrogen as an inert gas has been proposed and put into practical use (e.g., Japanese Patent Application Publication No. 2015-146349 (Patent Document 1)). Specifically, this EFEM includes: a circulation path that includes a transport space for circulating nitrogen within the transport chamber; a gas supply unit that supplies nitrogen to the circulation path; and a gas discharge unit that discharges nitrogen from the circulation path. Nitrogen is supplied and discharged appropriately according to changes in oxygen concentration, etc., within the circulation path. Thus, compared to a structure that constantly supplies and discharges nitrogen, it is possible to suppress increases in the amount of nitrogen supplied and maintain a nitrogen atmosphere within the transport chamber.

[0006] However, in the next-generation semiconductor device manufacturing process, characterized by miniaturization and multilayering at the nanoscale, achieving improved yield and consistent quality requires isolating the substrate handling space from the external atmosphere and providing oxidation and corrosion resistance under a high-purity nitrogen atmosphere (extremely low oxygen concentration and humidity). To meet these demands, previously neglected environmental aspects of the handling chamber require higher levels of management. Specifically, the required levels include low humidity (for example, below the dew point humidity of -50 degrees Celsius) and low oxygen concentration (for example, 100 ppm). Furthermore, with the miniaturization and multilayering of semiconductors, substrate degradation during semiconductor manufacturing has become a problem. Harmful substances that degrade the substrate are released from it after processing and time has passed.

[0007] Therefore, in recent years, not only has a bottom purging process been adopted, in which nitrogen is purged into the FOUP before the FOUP door is opened, but also a structure is adopted in which nitrogen is continuously supplied from the bottom purging nozzle to the substrate that is in standby in the FOUP after the FOUP door is opened. This has formed a countermeasure to prevent and suppress the deterioration of the substrate in standby. Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, in the previous EFEM, since the nitrogen supply to the transfer chamber and the nitrogen supply to the loading port during bottom purging were controlled separately, when the FOUP door was opened while the FOUP was docked with the frame and bottom purging was continued, more nitrogen flowed into the frame than was intended, causing the pressure inside the frame to increase.

[0010] In addition, when the pressure is higher than the predetermined value, although nitrogen can be vented from the vent, this venting is done solely to reduce pressure regardless of whether the oxygen concentration or humidity is abnormal, which may result in a waste of nitrogen.

[0011] This invention was developed with this problem in mind, and its main objective is to provide an EFEM that can maintain a slightly positive pressure within the frame at a predetermined usage amount while avoiding nitrogen waste, and a method for controlling the supply of inert gas into the EFEM. Furthermore, this invention is a technology that can be applied even to substrate storage containers other than FOUPs.

[0012] Methods for solving problems

[0013] That is, the present invention relates to an EFEM, comprising: a frame having an internally enclosed substrate transport space; and a control unit for controlling at least the supply of inert gas into the frame. Furthermore, the EFEM of the present invention is characterized in that the control unit comprises: an inert gas supply total amount setting unit, which sets the total amount of inert gas supplied into the frame based on the oxygen concentration within the frame; a door opening and purging determination unit, which, for each loading port, determines whether the container door of the substrate storage container placed on a mounting platform capable of holding a substrate storage container is open and whether it is undergoing purging processing by a purging device capable of replacing the gas atmosphere within the substrate storage container placed on the mounting platform with inert gas; and the frame interior... The inert gas supply amount calculation unit calculates the amount of inert gas supplied to the frame when the door opening and purging determination unit determines that the inert gas supply amount is yes. This is based on the value obtained by subtracting the amount of inert gas supplied to the substrate storage container by the purging device of the loading port, i.e., the amount of inert gas supplied to the container, from the total amount of inert gas supplied by the inert gas supply amount setting unit. The control unit is configured to control the amount of inert gas supplied to the frame by using the inert gas supply amount command value determined based on the calculation result of the inert gas supply amount calculation unit in the frame.

[0014] The inventors have developed a novel and useful technical concept that controls the supply of inert gas (nitrogen, for example) to the housing by adopting a purging implementation based on the loading port, thereby avoiding nitrogen waste and enabling the EFEM to maintain a slightly positive pressure in the transport chamber of the EFEM at a predetermined usage amount.

[0015] That is, in the EFEM of the present invention, the amount of inert gas supplied to the frame is set based on the oxygen concentration inside the frame. When a purging process performed by a purging device is carried out with the container door open (when the determination result of the door opening and purging determination unit is "yes"), the amount of inert gas supplied during the purging process (the amount of inert gas supplied inside the container) is subtracted from the total amount of inert gas supplied. Based on this subtraction value, an instruction value for the amount of inert gas supplied to the frame, namely the inert gas supply instruction value, is determined, and the amount of inert gas supplied to the frame is controlled based on this inert gas supply instruction value. Thus, the amount of inert gas supplied during the purging process can be taken into account and controlled to not exceed the upper limit of the gas supply to the entire EFEM (the total amount of inert gas supplied based on the oxygen concentration inside the frame). This avoids the waste of inert gas, such as the discharge of inert gas from the frame even when the oxygen concentration does not change, saves inert gas, and keeps the pressure inside the EFEM frame at a slightly positive pressure with a predetermined usage amount.

[0016] In particular, in the EFEM according to the present invention, during the process of controlling the supply of inert gas to the frame, when changing the inert gas supply amount to the frame to the inert gas supply amount command value determined based on the calculation result of the inert gas supply amount calculation unit in the frame (when updating the inert gas supply amount command value determined based on the calculation result of the inert gas supply amount calculation unit in the frame to the latest inert gas supply amount command value), the control is performed in a manner that takes a predetermined time to gradually change, thereby preventing and suppressing abrupt pressure changes in the frame.

[0017] In the case of the EFEM of the present invention, which includes an inert gas supply device inside a substrate handling robot that supplies inert gas to the interior of a substrate handling robot arranged in a substrate handling space, or an ionization device that performs charge removal of a substrate by locally supplying inert gas to a substrate placed at a predetermined location in the substrate handling space, it is preferable to also consider the inert gas supply amount of these structures when calculating and determining the inert gas supply amount command value. Specifically, the preferred configuration is that, when the inert gas supply device inside the handling robot is in an inert gas supply state, the inert gas supply amount calculation unit inside the frame calculates the amount of inert gas supplied to the frame based on a value obtained by subtracting at least the inert gas supply amount of the inert gas supply device inside the handling robot and the inert gas supply amount inside the container from the total inert gas supply amount set by the inert gas supply amount setting unit; or, when the ionization device is in an inert gas supply state, the inert gas supply amount calculation unit inside the frame calculates the amount of inert gas supplied to the frame based on a value obtained by subtracting at least the inert gas supply amount of the ionization device and the inert gas supply amount inside the container from the total inert gas supply amount set by the inert gas supply amount setting unit.

[0018] Furthermore, the inert gas supply control method of the present invention can be applied to an inert gas supply control method for an EFEM (Enhanced Electronic Precipitation Machine), which includes: a frame having a generally enclosed substrate transport space inside; and a control unit for controlling the supply of inert gas into the frame. The inert gas supply control method is characterized by comprising an inert gas supply total quantity setting step, a door opening and purging determination step, an inert gas supply quantity calculation step within the frame, and an inert gas supply quantity control step. Specifically, the inert gas supply total quantity setting step sets the total inert gas supply quantity to the frame based on the oxygen concentration within the frame; the door opening and purging determination step determines the inert gas supply quantity for each loading port adjacent to the frame. The steps for calculating the inert gas supply within the frame are as follows: First, the door of the substrate storage container, placed on the loading port, is open, and second, it is being purged by a purging device. Third, the steps for controlling the inert gas supply within the frame are as follows: If the door is open and the purging determination step is yes, the inert gas supply within the frame is calculated based on the value obtained by subtracting the inert gas supply amount from the purging device at the loading port to the substrate storage container (i.e., the inert gas supply within the container) from the total inert gas supply amount set in the inert gas supply total amount setting step. Fourth, the steps for controlling the inert gas supply within the frame are as follows: The inert gas supply amount is controlled based on the calculation result in the inert gas supply amount calculation step.

[0019] According to the inert gas supply control method of the present invention, the same effect as that achieved by the EFEM of the present invention described above can be obtained, and the situation of supplying more than the initially controlled amount of inert gas into the frame can be avoided. As a result, the pressure rise inside the frame can be prevented, and the problem caused by supplying excess inert gas can be eliminated. That is, the problem of inert gas waste caused by the discharge of inert gas even if the oxygen concentration does not change can be eliminated, and inert gas can be conserved.

[0020] Invention Effects

[0021] According to the present invention, when supplying an inert gas such as nitrogen into the frame, the inert gas supply is controlled based on a value calculated by subtracting the gas supply from the gas supply amount supplied to the substrate housing container by the purging device of the loading port (inert gas supply amount in the container) from the initial control amount of gas supply into the frame. Therefore, it is possible to provide an EFEM that can avoid the waste of inert gas and maintain the pressure in the frame at a slightly positive pressure with a predetermined amount of usage, as well as an inert gas supply control method in the EFEM. Simple Explanation of the Diagram

[0022] Figure 1 is a side view schematically showing the relative positional relationship between the EFEM and its peripheral devices according to an embodiment of the present invention. Figure 2 is a schematic diagram illustrating the gas piping system in this embodiment. Figure 3 is a functional block diagram of the control unit in this embodiment. Figure 4 is a diagram showing an example of an oxygen concentration control table in this embodiment. Figure 5 is a simplified flowchart of the inert gas supply control within the frame in this embodiment. Figure 6 is a flowchart (detailed version) of the inert gas supply control within the frame in this embodiment. Figure 7 is a diagram showing an example of an oxygen concentration control table in this embodiment. Implementation

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0024] As shown in Figure 1, the EFEM1 (Equipment Front End Module) of this embodiment includes a frame 2 and a loading port 3, which are disposed in a cleanroom as the main body, in the semiconductor manufacturing process. Figure 1 schematically shows the relative positional relationship between the EFEM1 and its peripheral devices. The FOUP4 shown in the figure is a type of "substrate storage container" in this invention, used in conjunction with the EFEM1.

[0025] A processing device M (semiconductor processing device) is disposed adjacent to the front surface wall 2a where the loading port 3 is disposed in the frame 2. That is, by connecting the loading port 3 to the opening provided in the front surface wall 2a of the frame 2 and connecting the processing device M to the opening provided in the back surface wall 2b, a substantially enclosed space (substrate transport space 2Sa, FFU placement space 2Sb) is formed inside the frame 2.

[0026] In the cleanroom, the internal space MS of the processing device M, the substrate transport space 2Sa which is the internal space of the frame 2, the FFU setting space 2Sb, and the internal space 4S of the FOUP4 placed on the loading port 3 are maintained at a high level of cleanliness.

[0027] In this embodiment, as shown in FIG1, the loading port 3, the frame 2, and the processing device M are arranged in close contact with each other in the front-rear direction X of EFEM1. Furthermore, the operation of EFEM1 is controlled by the controller of EFEM1 as a whole (control unit 1C shown in FIG1) and the controller of the loading port 3 (control unit 3C shown in FIG1), and the operation of the processing device M is controlled by the controller of the processing device M (control unit MC shown in FIG1). Here, the control unit MC, which is the controller of the processing device M as a whole, and the control unit 1C, which is the controller of EFEM1 as a whole, are the upper-level controllers of the control unit 3C of the loading port 3. These control units 1C, 3C, and MC are composed of a typical microprocessor including a CPU, memory, and interface. The programs required for processing are pre-stored in the memory, and the CPU sequentially retrieves and executes the necessary programs, cooperating with peripheral hardware resources to achieve the desired function.

[0028] A substrate handling robot R (see Figure 1) capable of handling substrates W (semiconductor wafers) between FOUP4 and processing device M is installed in the substrate handling space 2Sa, which is the internal space of the frame 2. An FFU 23 (fan filter unit) is installed in the FFU placement space 2Sb, which is located above the substrate handling space 2Sa within the internal space of the frame 2. By driving the FFU 23, a downward airflow is generated in the substrate handling space 2Sa of the frame 2, allowing inert gases (ambient gases) such as nitrogen, which are highly clean, to circulate within the substrate handling space 2Sa. A circulation path 21 for circulating nitrogen is formed inside the frame 2. The circulation path 21 consists of the substrate handling space 2Sa, the FFU placement space 2Sb, and a return path 22. In the circulation path 21, clean nitrogen is sent downward from the FFU placement space 2Sb through the FFU 23, reaches the lower end of the substrate handling space 2Sa, and then rises through the return path 22, returning to the FFU placement space 2Sb.

[0029] FFU23 delivers nitrogen gas downwards from FFU placement space 2Sb via a fan, and removes particulate matter from the nitrogen gas using a filter. The purified nitrogen gas is then sent from FFU placement space 2Sb to substrate transport space 2Sa in a laminar flow and flows downwards. Nitrogen gas reaching the lower end of substrate transport space 2Sa flows into return path 22 through opening 22a formed at the lower end of return path 22. In this embodiment, a fan 22b located above opening 22a draws nitrogen gas into return path 22 and sends it upwards, returning it to FFU placement space 2Sb. The nitrogen gas returning to FFU placement space 2Sb is purified by FFU23 and sent back to substrate transport space 2Sa. Furthermore, return path 22 is a path separated from substrate transport space 2Sa and FFU placement space 2Sb by partition wall 22c (appropriate support wall, etc.), configured such that only opening 22a formed at the lower end of return path 22 communicates with substrate transport space 2Sa, and only the upper end of return path 22 communicates with FFU placement space 2Sb.

[0030] With the above structure, nitrogen gas can circulate within the circulation path 21. A supply path 51 for supplying nitrogen gas into the circulation path 21 is connected to the side of the FFU installation space 2Sb. As shown in FIG2, the supply path 51 is connected to the nitrogen gas supply source 50. At a predetermined location in the supply path 51, an MFC 51a (mass flow controller) for measuring and controlling the flow rate of the supply path 51, which serves as a gas flow path, and a supply valve 51b for changing the amount of gas supplied per unit time are provided. In this embodiment, a secondary supply path 52 is provided, branching from a predetermined location in the supply path 51 upstream of the MFC 51a and the supply valve 51b, and the secondary supply path 52 is connected to a predetermined location in the supply path 51 downstream of the MFC 51a and the supply valve 51b. A supply valve 52b for switching the nitrogen gas supply on / off is provided at a predetermined location in the secondary supply path 52. Furthermore, "FM" shown in FIG2 stands for flow meter 52a. Therefore, in this embodiment, a portion of the gas supply to the circulation path 21 can take over the gas supply that has passed through the secondary supply path 52. In this embodiment, the supply source of the supply path 51 is configured to be switchable to either the nitrogen supply source 50 described above or the CDA (clean air) supply source shown in FIG2. The lowercase Roman numerals shown in FIG1 are used in the same sense as the lowercase Roman numerals shown in FIG2.

[0031] Additionally, as shown in Figure 1, a discharge pipe 22d for discharging gas from the circulation path 21 is connected to the front end of the substrate transport space 2Sa. The discharge pipe 22d communicates with the external space. A discharge valve is provided at a predetermined position on the discharge pipe 22d. This discharge valve is controlled according to the pressure of the frame 2 and can change the amount of gas discharged per unit time in the circulation path 21. Thus, nitrogen can be appropriately supplied and discharged into the circulation path 21 to perform a process for adjusting the oxygen concentration in the internal space of the frame 2 (also known as a frame purging process or EFEM purging process). For example, if the oxygen concentration in the circulation path 21 increases, a large amount of nitrogen is temporarily supplied to the circulation path 21 from the supply source 50 via the supply path 51 (including the auxiliary supply path 52), and oxygen is discharged along with the nitrogen via the discharge pipe 22d, thereby reducing the oxygen concentration. The control unit 1C is electrically connected to the oxygen concentration meter 2e, pressure meter 2f, hygrometer 2g, etc. installed in the frame 2, and receives the measurement results of these measuring devices to obtain information related to the atmosphere in the frame 2 (in Figure 1, for ease of explanation, the oxygen concentration meter 2e, pressure meter 2f, hygrometer 2g and control unit 1C are shown together on the outside of the frame 2).

[0032] As shown in Figure 1, the FOUP4 placed in the loading port 3 includes a FOUP body 42 that opens only to the rear through the loading / unloading outlet 41 to the internal space 4S, and a FOUP door 43 (equivalent to the "container door 43" of the present invention) that can open and close the loading / unloading outlet 41. The FOUP4 is a known device configured to have multi-level slots inside, in which substrates W, which are transport objects, can be stored, and which can be removed and placed through the loading / unloading outlet 41. A flange portion 44 is provided on the upper surface of the FOUP body 42 for being held by an automatic transport device (e.g., OHT: Overhead Transport). The FOUP4 is placed on the loading platform 35 of the loading port 3. A port (not shown) is provided on the bottom wall of the FOUP body 42. The port is, for example, a hollow cylindrical cable ring seal that is embedded in a port mounting through hole formed in the bottom wall of the FOUP body 42, and is configured to be openable and closed by a one-way valve.

[0033] As shown in Figure 1, the loading port 3 of this embodiment includes: a frame 32, which forms part of the front surface wall 2a of the frame 2 and has an opening 31 for opening the internal space (substrate transport space 2Sa) of the frame 2; a loading port door 33, which opens and closes the opening 31 of the frame 32; a door opening and closing mechanism 34, which opens the opening 31 of the frame 32 by moving the loading port door 33 to a door opening position that moves backward toward the frame 2; and a mounting platform 35, which is disposed on the frame 32 in a generally horizontal posture.

[0034] The frame 32 is configured in an upright position and is a generally rectangular plate-shaped frame. The frame includes an opening 31 of a size that communicates with the loading and unloading outlet 41 of the FOUP4 placed on the loading platform 35. Figure 1 schematically shows the opening 31 of the frame 32.

[0035] The mounting platform 35 is positioned above a horizontal base 351 (support platform) located slightly above the center of the frame 32 in a generally horizontal orientation. It allows the FOUP 4 to be mounted with the FOUP door 43 facing the loading port 33, and the FOUP door 43 can open and close the internal space 4S of the FOUP body 42. Furthermore, the mounting platform 35 is configured to move back and forth relative to the frame 32 between a predetermined docking position where the FOUP door 43 approaches the opening 31 of the frame 32 and a position where the FOUP door 43 is moved away from the frame 32 by a predetermined distance from the docking position (see Figure 1). In this embodiment, in the front-rear direction X (see Figure 1, etc.) of the FOUP 4 mounted on the mounting platform 35 and the frame 32, the FOUP 4 side is defined as the front, and the frame 32 side is defined as the rear.

[0036] The loading port door 33 is configured to move integrally with the FOUP door 43 while being engaged with the FOUP door 43 via the door opening and closing mechanism 34. This movement occurs between three positions: a fully closed position (where the opening 31 of the sealed frame 32 is fully closed), a door-open position (where the opening is retracted towards the frame 2 compared to the fully closed position), and a fully open position (where the opening space of the opening 31 is fully open to the rear). Furthermore, as shown in FIG1, the loading port door 33 and the door opening and closing mechanism 34 are positioned to overlap with the return path 22 of the circulation path 21 when viewed from the side. However, in practice, the circulation path 21 is arranged at predetermined intervals in the width direction of the frame 2. The loading port door 33 moves integrally with the FOUP door 43 via the door opening and closing mechanism 34 within the space formed between the circulation paths 21 arranged in the width direction and communicating with the substrate transport space 2Sa. Therefore, the loading port door 33 does not move together with the FOUP door 43 in the return path 22.

[0037] The loading port 3 of this embodiment includes a bottom purging device 36 (equivalent to the "purging device" of the present invention) that injects a purging gas composed of an inert gas such as nitrogen into the internal space 4S of the FOUP4, and can replace the gas atmosphere of the internal space 4S of the FOUP4 with the purging gas. The bottom purging device 36 includes a plurality of purging nozzles 37 (gas supply and exhaust devices) arranged at predetermined positions on the mounting platform 35 in a state that allows the upper end to be exposed. These plurality of purging nozzles 37 are installed at appropriate positions on the mounting platform 35 according to the position of the port provided on the bottom surface of the FOUP4, and can be connected in a state of contact with the port. The bottom purging process using such a bottom purging device 36 (equivalent to the "purging process" of the present invention) is as follows: a predetermined number (excluding all) of the multiple ports provided at the bottom of the FOUP4 are used as "supply ports," and a suitable purging gas, such as nitrogen, inert gas, or dry air, is injected into the FOUP4 through a purging nozzle 37 connected to the supply port. The remaining ports are used as "exhaust ports," and the gaseous atmosphere inside the FOUP4 is discharged through a purging nozzle 37 connected to the exhaust port, thereby filling the FOUP4 with purging gas. Each loading port 3 includes a supply path 61 for supplying nitrogen to the purging nozzle 37 connected to the supply port. As shown in FIG2, the supply path 61 is connected to a nitrogen supply source 60 for bottom purging. Furthermore, "LP purging" in FIG2 refers to loading port purging, indicating that the supply source 60 is the nitrogen supply source for bottom purging. A mass flow controller (MFC) 61a, which measures and controls the flow rate of the gas supply path 61, and a supply valve 61b, which can change the amount of gas supplied per unit time, are provided at a predetermined location in the supply path 61. In addition, a discharge pipe (not shown) for discharging gas from FOUP4 is connected to a purge nozzle connected to the exhaust port.

[0038] As shown in Figure 1, the substrate handling robot R is a multi-joint robot, comprising a base portion R1 fixed within the substrate handling space 2Sa, and an arm R2 whose base end is rotatably supported on the base portion R1. Multiple arm elements R3, R4, R5, and a robotic hand R6 constituting the arm R2 are sequentially rotatably connected. In this embodiment, the arm R2 includes three arm elements R3, R4, and R5 and two (two-segment) robotic hands R6. The arm elements R3, R4, and R5 rotate, thereby allowing the robotic hands R6, which hold the substrate W, to move horizontally. Furthermore, the number of arm elements and hands is not limited to this. The arm elements R3, R4, and R5 are arranged in this order from below. Specifically, the base of the lowest arm element R3 is rotatably connected to the base R1, the base of the middle arm element R4 is rotatably connected to the top of the lowest arm element R3, the base of the highest arm element R5 is rotatably connected to the top of the middle arm element R4, and the robot hand R6 is rotatably connected to the top of the highest arm element R5.

[0039] The internal spaces R3a, R4a, and R5a of each arm element R3, R4, and R5 are interconnected via predetermined gaps. The base plate W can be held in the robot hand R6 by mechanisms such as the cylinder R7 built into the robot hand R6. The rod (not shown) of the cylinder R7 is configured to extend and retract in a predetermined direction by supplying nitrogen from a different supply source (not shown) than the aforementioned supply source 50.

[0040] The EFEM1 houses an injector R8 inside the substrate handling robot R, which removes particles generated by the movement of cylinder R7. Nitrogen is supplied to the injector R8 from the supply source 50 via supply path 53, thereby attracting particles generated by the movement of the cylinder and other mechanical components via attraction path 531. The nitrogen supplied to the injector R8, along with the attracted particles, flows to the appropriate path (connection path R12 described later) and is then sent to the return path 22. That is, the nitrogen is not directly discharged into the external space of the frame 2, but flows into the circulation path 21. Thus, by attracting particles generated near cylinder R7 through the injector R8, and discharging the nitrogen supplied from the supply source 50 along with the particles into the return path 22, the nitrogen is directly circulated. Furthermore, the particles are removed by FFU 23. Therefore, compared to a structure that requires vacuum venting, the increase in cost due to nitrogen replenishment can be suppressed. In this embodiment, the nitrogen supply source 50 supplying nitrogen to the injector R8 is the same as the nitrogen supply source 50 supplying nitrogen to the circulation path 21 (supply source sharing). A supply valve 53b for switching the nitrogen supply on / off is provided at a predetermined position in the supply path 53 leading to the injector R8. Furthermore, "FM" shown in FIG2 refers to a flow meter 53a. The supply path 53 leading to the injector R8 branches off from a predetermined position upstream of the MFC 51a and the supply valve 51b in the supply path 51, which functions as the gas supply path during the aforementioned purging process within the housing.

[0041] Furthermore, an outlet R11 for supplying nitrogen gas to the circulation path 21 is formed at a predetermined location on the base portion R1 of the handling robot R, and the outlet R11 is connected to the return path 22 via a connecting path R12. Near the outlet R11, a fan R13 driven to rotate at a fixed speed is provided. The EFEM1 of this embodiment includes a supply path 54 passing through the internal space R1a of the base portion R1 and the internal spaces R3a, R4a, and R5a of the arm elements R3, R4, and R5, with the front end of the supply path 54 positioned within the internal space R5a of the uppermost arm element R5. If an inert gas such as nitrogen is supplied from the supply source 50 to the supply path 54, the inert gas is supplied to the internal space R5a of the uppermost arm element R5 through the supply path 54. Then, it flows sequentially into the internal space R4a of the middle arm element R4, the internal space R3a of the lowermost arm element R3, and the internal space R1a of the base R1, and is discharged to the return path 22 through the outlet R11 of the base R1. In this way, the gas in the internal space of the handling robot R (the internal space R1a of the base R1, and the internal spaces R3a, R4a, and R5a of the arm elements R3, R4, and R5) can be replaced with an inert gas such as nitrogen.

[0042] Thus, the EFEM1 of this embodiment includes an internal purging device R9 that replaces the gas in the internal space of the transport robot R (the internal space R1a of the base portion R1, and the internal spaces R3a, R4a, and R5a of the arm elements R3, R4, and R5) with an inert gas such as nitrogen. Therefore, even if particles are generated in the internal space of the transport robot R (the internal space R1a of the base portion R1, and the internal spaces R3a, R4a, and R5a of the arm elements R3, R4, and R5), leakage of these particles into the substrate transport space 2Sa can be suppressed. Furthermore, particles discharged to the return path 22 are removed by an FFU 23 disposed downstream of the return path 22. Therefore, it is possible to suppress the contamination of the substrate transport space 2Sa due to particles generated in the internal space of the substrate transport robot R (the internal space R1a of the base portion R1, and the internal spaces R3a, R4a, and R5a of the arm elements R3, R4, and R5). In this embodiment, the nitrogen supply source 50 supplying nitrogen to the purging device R9 inside the transport robot is the same as the nitrogen supply source 50 supplying nitrogen to the circulation path 21 (supply source sharing). A supply valve 54b for switching the nitrogen supply on / off is provided at a predetermined position in the supply path 54. The supply path 54 supplying nitrogen to the purging device R9 inside the transport robot branches off from a predetermined position upstream of the supply path 51, which functions as a gas supply path during the purging process within the aforementioned frame, compared to the MFC 51a and the supply valve 51b.

[0043] The aforementioned injector R8 and the internal purging device R9 of the transport robot are respectively equivalent to the "inert gas supply device inside the transport robot that supplies inert gas to the internal space of the substrate transport robot" in this invention.

[0044] As shown in Figure 1, in this embodiment, EFEM1 detects the offset of the substrate W held in the holding position of the arm R2 of the transport robot R relative to the target holding position, and sets an aligner 7 for position correction (alignment) to correct the position offset in the substrate transport space 2Sa. The aligner 7 includes an alignment stage 71 that holds the substrate W, which is the object of alignment, and a through-hole 73 connected to a return path 22 via a connection path 74. The through-hole 73 is formed in the side wall of an alignment frame 72, which has a built-in mechanism for rotating and driving the alignment stage 71. In this embodiment, a fan 75 is configured to be provided near the through-hole 73 of the alignment frame 72. When the fan 75 is rotated, the gas in the alignment frame 72 and the particles generated in the alignment frame 72 are discharged toward the connection path 74.

[0045] The EFEM1 of this embodiment includes an ionization device 8 that blows nitrogen gas, which serves as ionizing air, from above onto a substrate placed on an alignment stage 71. The ionization device 8 is connected to a supply path 55 through which inert gas flows from a supply source 50. By blowing the inert gas (ionized air) supplied from the supply source 50 onto the substrate W placed on the alignment stage 71, static electricity charged on the substrate W can be neutralized / removed (electrostatically removed). In this embodiment, as shown in FIG2, the supply source 50 that supplies nitrogen gas to the ionization device 8 is the same as the supply source 50 that supplies nitrogen gas into the circulation path 21 (supply source sharing). A supply valve 55b for switching the nitrogen gas supply on / off is provided at a predetermined location on the supply path 55 leading to the ionization device 8. "FM" in FIG2 refers to a flow meter 55a. The supply path 55 to the ionization device 8 branches off from a predetermined location upstream of the MFC 51a and the supply valve 51b in the supply path 51, which functions as a gas supply path during the purging process in the aforementioned housing.

[0046] Next, the operation flow of EFEM1 will be explained.

[0047] First, the FOUP4 is moved to the top of the loading port 3 using a container handling device such as an OHT, and placed on the mounting platform 35. At this time, for example, a positioning protrusion provided on the mounting platform 35 is inserted into the positioning recess of the FOUP4, so that the locking claw on the mounting platform 35 is locked (locking process). In this embodiment, the FOUP4 can be placed on the mounting platform 35 of the loading port 3, which is arranged with three units in the width direction of the frame 2. In addition, the FOUP4 can be configured to detect the correct position of the FOUP4 on the mounting platform 35 by a placement sensor (not shown) that detects whether the FOUP4 is placed at a predetermined position on the mounting platform 35.

[0048] In the loading port 3 of this embodiment, at the time when the FOUP4 is placed in the correct position on the mounting stage 35, the pressure of the bottom surface of the FOUP4 against the pressed portion, such as a pressure sensor, provided on the mounting stage 35, is detected. Taking this opportunity, the purge nozzles 37 (all purge nozzles 37) provided on the mounting stage 35 enter upwards relative to the upper surface of the mounting stage 35 and connect to each port of the FOUP4, switching each port from a closed state to an open state. Furthermore, the loading port 3 of this embodiment supplies nitrogen gas to the internal space 4S of the FOUP4 via the bottom purge device 36, performing a process to replace the internal space 4S of the FOUP4 with nitrogen gas (bottom purge process). During the bottom purge process, the gaseous atmosphere inside the FOUP4 is discharged out of the FOUP4 from the purge nozzles 37 connected to the port that functions as an exhaust port. Through this bottom purge process, the moisture concentration and oxygen concentration inside the FOUP4 are reduced to below predetermined values, creating a low-humidity and low-oxygen environment around the substrate W inside the FOUP4. The nitrogen supply to the internal space 4S of FOUP4 during bottom purging can be changed by using MFC61a for bottom purging, and the nitrogen supply flow rate can be changed according to the moisture concentration and oxygen concentration in FOUP4.

[0049] After the loading port 3 in this embodiment is locked, the loading platform 35, located at the position shown in FIG1, is moved to a predetermined docking position, thereby causing the FOUP door 43 to fit tightly against the frame 32. Then, the FOUP door 43 and the loading port door 33 are moved together to open the opening 31 of the frame 32 and the loading / unloading outlet 41 of the FOUP 4, performing a process to release the sealed state inside the FOUP 4 (door opening process). By performing the door opening process, the internal space 4S of the FOUP body 42 is connected to the substrate transport space 2Sa of the frame 2. The substrate transport robot R, located in the substrate transport space 2Sa of the frame 2, performs a process to remove the substrate W from the slot of the FOUP body 42 or to store the substrate W in a specific slot (transport process).

[0050] In this embodiment, when all the substrates W inside the FOUP4 have completed the processing steps of the processing device M, the loading port 33 is moved to the fully closed position by the door drive mechanism (door opening and closing mechanism 34), closing the opening 31 of the frame 32 and the loading / unloading outlet 41 of the FOUP4, and performing the process of sealing the internal space 4S of the FOUP4 (door closing process). Through the above process, the opening 31 of the frame 32 and the loading / unloading outlet 41 of the FOUP4 are closed by the loading port 33 and the FOUP door 43 respectively, and the internal space 4S of the FOUP4 becomes a sealed state.

[0051] Next, the loading port 3 of this embodiment moves the mounting stage 35 away from the frame 32, releasing the locked state of the FOUP4. As a result, the FOUP4 containing the substrate W that has completed the predetermined processing is transferred from the mounting stage 35 of each loading port 3 to the container transport device and transported to the next process.

[0052] In the EFEM1 of this embodiment, which follows this operational process, by continuing the bottom purging process performed at the time point before the door opening process even after the door opening process, degradation of the substrate during standby within the FOUP4 can be prevented and suppressed. On the other hand, by continuing the bottom purging process even after the door opening process, nitrogen gas, used as the purging gas, flows from the FOUP4 into the frame 2, potentially increasing the pressure within the frame 2. To avoid this, the EFEM1 of this embodiment is configured to control the amount of inert gas supplied to the frame 2 via a control unit 1C. Specifically, the control unit 1C is configured to control the amount of inert gas supplied to the frame 2 based on an inert gas supply amount command value.

[0053] As shown in Figure 3, the control unit 1C includes an inert gas supply total setting unit 11, a door opening and bottom purging determination unit 12 (equivalent to the "door opening and purging determination unit" of the present invention), an inert gas supply amount calculation unit 13 inside the frame, and an instruction value determination unit 14.

[0054] The inert gas supply total setting unit 11 sets the total amount of inert gas supplied to the frame 2 based on the oxygen concentration inside the frame 2. In this embodiment, as shown in FIG4, the total amount of inert gas supplied to the frame 2 corresponding to the oxygen concentration inside the frame 2 is stored as an oxygen concentration control table in a predetermined storage area of ​​the control unit 1C.

[0055] The door opening and bottom purging determination unit 12 determines for each loading port 3 whether the container door 43 of the FOUP 4 placed on the loading platform 35 of that loading port 3 is open and whether it is undergoing bottom purging processing by the bottom purging device 36. Whether the container door 43 of the FOUP 4 is open can be determined by an appropriate sensor (e.g., a "ko"-shaped miniature photosensitive sensor) provided near the container door 43 of the FOUP 4 in the loading port 3, and whether it is undergoing bottom purging processing by the bottom purging device 36 can be determined by an appropriate sensor (gas flow meter, etc.) provided in association with the bottom purging device 36. The EFEM1 of this embodiment includes 3 loading ports 3, therefore the determination process performed by the door opening and bottom purging determination unit 12 is performed for each loading port 3 (a total of 3 times).

[0056] When the door is open and the bottom purging determination unit 12 determines "yes", the inert gas supply calculation unit 13 calculates the inert gas supply amount to the frame 2 based on the value obtained by subtracting the bottom purging inert gas supply amount (equivalent to the "in-container inert gas supply amount" of the present invention) from the inert gas supply amount set by the inert gas supply total amount setting unit 11. The bottom purging inert gas supply amount (bottom purging inert gas supply amount) from the bottom purging device 36 to the FOUP4 is a variable value based on the oxygen concentration in the FOUP4, the bottom purging treatment duration, etc., and this value (bottom purging inert gas supply amount) is based on the command value of the bottom purging MFC 61a. Therefore, by using an appropriate method to determine the command value of the bottom purging MFC 61a, the bottom purging inert gas supply amount (bottom purging inert gas supply amount) from the bottom purging device 36 to the FOUP4 can be determined, and this determined value can be used for calculation processing in the inert gas supply amount calculation unit 13. Furthermore, when the inert gas supply calculation unit 13 inside the frame determines "no" when the door is open and the bottom purging determination unit 12 determines "no" (when the container door 43 of the FOUP4 placed on the loading port 35 is closed, or when the bottom purging process performed by the bottom purging device 36 is not performed), the value subtracted from the total inert gas supply set by the inert gas supply total setting unit 11 is zero (the bottom purging device 36 of the loading port 3 supplies zero inert gas to the bottom of the FOUP4), and the inert gas supply amount to the frame 2 is calculated.

[0057] Furthermore, when the inert gas supply device inside the transport robot is in an inert gas supply state, the inert gas supply amount calculation unit 13 inside the frame is configured to calculate the amount of inert gas supplied to the frame 2 by subtracting the amount of inert gas supplied by the inert gas supply device inside the transport robot from the total amount of inert gas supply set by the total amount of inert gas supply set by the inert gas supply amount setting unit 11. In this embodiment, the injector R8 and the purging device R9 inside the transport robot are respectively equivalent to the inert gas supply device inside the transport robot. When the injector R8 is in an inert gas supply state, the inert gas supply amount calculation unit 13 inside the frame is configured to calculate the amount of inert gas supplied to the frame 2 by subtracting the amount of inert gas supplied by the injector R8 from the total amount of inert gas supply, or when the purging device R9 inside the transport robot is in an inert gas supply state, the inert gas supply amount calculation unit 13 inside the frame is configured to calculate the amount of inert gas supplied to the frame 2 by subtracting the amount of inert gas supplied by the purging device R9 inside the transport robot from the total amount of inert gas supply.

[0058] In addition, in this embodiment, when the ionization device 8 is in an inert gas supply state, the inert gas supply amount calculation unit 13 in the housing calculates the inert gas supply amount to the housing 2 by subtracting the inert gas supply amount of the ionization device 8 from the total inert gas supply amount.

[0059] Here, in the oxygen concentration control table of Figure 4, column C is related to the inert gas supply amount of the "Robot Ejector" (ejector R8), column D is related to the inert gas supply amount of the "Robot Inner Purge" (transport robot inner purging device R9), and column E is related to the inert gas supply amount of the "Ionizer Purge" (ionizer 8). Additionally, column B in the oxygen concentration control table is related to the inert gas supply amount to the housing 2 via the "Main Purge," i.e., through the aforementioned secondary supply path 52. The supply amounts in columns B through E are not variable based on the oxygen concentration of housing 2 (oxygen concentration within the EFEM), but are either zero or constant (fixed values).

[0060] The instruction value determination unit 14 determines the inert gas supply amount instruction value to be supplied to the frame 2 based on the calculation result of the inert gas supply amount calculation unit 13 within the frame. In this embodiment, the configuration is such that when the inert gas supply amount to the frame 2 is changed (updated) to the inert gas supply amount instruction value determined based on the calculation result of the inert gas supply amount calculation unit 13 within the frame, that is, when the current inert gas supply amount instruction value is updated to the latest inert gas supply amount instruction value (the latest inert gas supply amount instruction value determined by the instruction value determination unit 14), a predetermined time is applied to gradually change the current inert gas supply amount instruction value to the latest inert gas supply amount instruction value.

[0061] When the EFEM1 in this embodiment is started with the power on, it enters a maintenance mode that performs atmospheric replacement treatment within the housing 2. In this maintenance mode, atmospheric replacement is performed within the housing 2 from less than 19.5% to more than 19.5%. The EFEM1 then transitions from the maintenance mode to the transport mode, and further from the transport mode to the additional oxygen concentration control transport mode. In the additional oxygen concentration control transport mode, inert gas supply control based on the control unit (oxygen concentration control within the housing) is implemented.

[0062] When the transition to the additional oxygen concentration control transport mode begins, EFEM1 monitors the value of the oxygen concentration meter 2e located at the appropriate position within the housing 2 to control the oxygen concentration in a constant manner (transportation chamber oxygen concentration control).

[0063] As described above, the oxygen concentration control table shown in FIG4 is pre-stored in a predetermined storage area of ​​the control unit 1C. Then, once per second, the following Equation 1 is calculated based on the oxygen concentration, and the amount of inert gas supplied to the frame 2, which is the object of control, is set according to the calculation result. Specifically, the flow rate of the MFC 51a for purging the frame is set at a predetermined position in the supply path 51 for supplying nitrogen to the circulation path 21 of the frame 2.

[0064] A(LPM)=T-(B+C+D+E+F+G+H)…Equation 1

[0065] Here, A to H in Equation 1 are synonyms with A to H in the oxygen concentration control table of Figure 4, respectively. A is the inert gas supply amount (EFEM MFC Purge) to the frame 2, which is the controlled object, specifically the flow command value of the MFC51a used for purging the frame, in LPM; liters / minute. T is the total amount of inert gas supplied to the frame 2 according to the oxygen concentration in the frame 2 (total N2 supply (LPM)). In addition, B, C, D, and E in Equation 1 are the main purging inert gas supply amount (Main Purge (LPM)), the robot ejector inert gas supply amount (Robot Ejector (LPM)), the robot inner purging inert gas supply amount (Robot Inner Purge (LPM)), and the ionizer inert gas supply amount (Ionizer Purge (LPM)), respectively. In Equation 1, F, G, and H represent the inert gas supply amounts (LP-1 MFC purge (LPM), LP-2 MFC purge (LPM), and LP-3 MFC purge (LPM)) of the bottom purging devices 36 at the first, second, and third loading ports, respectively. Columns N and T in the oxygen concentration control table represent individual parameters, while columns B to E represent the parameters for each column. Figure 3 shows an example of a preset value in the oxygen concentration control table.

[0066] In this embodiment, when "A<5", the flow rate setting of the MFC51a for purging the housing is set to 5 LPM. This is because the control range of the MFC51a for purging the housing is 4 to 200 LPM. For example, a flow rate setting of 2 LPM cannot be controlled by the MFC51a. In particular, if the flow rate is set to 0 (zero) LPM, the supply valve 51b for purging the housing needs to be closed. It is anticipated that the valve will be repeatedly opened / closed at the concentration boundary, and such repeated opening / closing of the valve should be avoided.

[0067] Next, referring to the simplified flowchart shown in FIG5 and the detailed flowchart shown in FIG6, the control unit 1C performs the above-mentioned Equation 1 calculation to control the oxygen concentration control in the frame (inert gas supply control in the frame) to control the amount of inert gas supplied to the frame 2.

[0068] In the EFEM1 of this embodiment, firstly, the control unit sets the total amount [T] (total inert gas supply) of inert gas supplied to the frame 2 via the inert gas supply total amount setting unit 11 (inert gas supply total amount setting step S1, see Figure 6). Specifically, the total inert gas supply [T] is set based on the oxygen concentration in the frame 2, referring to the oxygen concentration control table. At this time, [F], [G], and [H] in Formula 1, that is, the values ​​of the inert gas supply amount to the bottom of the FOUP4 by the bottom purging device 36 of each loading port 3, are cleared (set to a state where no value is assigned).

[0069] Next, the control unit 1C, through the door opening and bottom purging determination unit 12, determines for each loading port 3 whether the container door 43 of the FOUP4 placed on the loading platform of that loading port 3 is in an open state and whether it is undergoing bottom purging processing by the bottom purging device 36 (door opening and bottom purging determination step S2; equivalent to the "door opening and purging determination step" of the present invention). In the EFEM1 of this embodiment, the door opening and bottom purging determination step S2 is performed sequentially on all three loading ports.

[0070] If the determination result in the door opening and bottom purging determination step S2 is "yes", the control unit 1C calculates the inert gas supply amount [A] to the frame 2 based on the value obtained by subtracting the inert gas supply amount [F], [G], [H] of the bottom purging device 36 of the loading port 3 to the bottom of the FOUP 4 from the total inert gas supply amount [T] (inert gas supply amount calculation step S3). Alternatively, if the determination result in the door opening and bottom purging determination step S2 is "no", in the inert gas supply amount calculation step S3, the inert gas supply amount [F] of the bottom purging device 36 of the loading port 3 (e.g., the first loading port 3) to the bottom of the FOUP 4 is set to zero, and the inert gas supply amount [A] to the frame 2 is calculated. Figure 7 shows an example of an oxygen concentration control table under the following conditions: for the first loading port 3 out of 3 loading ports 3, the determination result of the door opening and bottom purging determination unit 12 is "yes" (the container door 43 of the FOUP4 placed on the loading platform 35 is open and the bottom purging process performed by the bottom purging device 36 is being carried out), and for the second and third loading ports 3, the determination result of the door opening and bottom purging determination unit 12 is "no".

[0071] Furthermore, in the inert gas supply calculation step S3 within the frame, when the inert gas supply device (ejector R8, purging device R9 within the transport robot) is in an inert gas supply state, or when the ionization device 8 is in an inert gas supply state, the inert gas supply amount [C], [D] of the inert gas supply device (ejector R8, purging device R9 within the transport robot) and the inert gas supply amount [E] of the ionization device 8 are subtracted from the total inert gas supply amount [T]. The oxygen concentration control table shown in Figure 7 is for the case where the container door 43 of the FOUP4 placed on the loading platform 35 of the first loading port is open and bottom purging is performed by the bottom purging device 36 at a flow rate of 50 MLP. According to the figure, for example, when the oxygen concentration in the frame 2 is 100 ppm, the total inert gas supply [T] is set to 310 LPM through the inert gas supply total setting step S1. In the inert gas supply amount calculation step S3, the inert gas supply amount in the frame is calculated by subtracting the inert gas supply amount [F] (LPM) from the bottom purging device 36 of the first loading port 3 to the bottom purging inert gas supply amount to FOUP4, i.e.,

[50] (LPM), from the total inert gas supply amount

[0310] (LPM). Thus, compared with the case where the bottom purging process of the bottom purging device 36 of all loading ports 3 is not implemented (Fig. 4), the inert gas supply amount [A] to the frame 2 becomes a value reduced by 50 LPM.

[0072] Next, the control unit 1C determines the inert gas supply command value [A] of the inert gas supply amount calculation unit 13 within the housing via the command value determination unit 14 (command value determination step S4). Then, if the inert gas supply command value [A] determined in the command value determination step S4 is different from the current inert gas supply command value (the flow rate command value of the current MFC51a for purging within the housing; [Acurrent], "current MFC command value" in FIG6), that is, if the threshold value for switching the total inert gas supply [T] relative to the oxygen concentration specified by the oxygen concentration control table is exceeded, it is determined whether this different state has lasted for "T1" seconds. "T1" is the time when the flow rate threshold is determined to be stably exceeded. In this embodiment, the preset value of "T1" is set to 20 seconds. That is, if the current inert gas supply command value [Acurrent] differs from the inert gas supply command value [A] determined in command value determination step S4, and if the current inert gas supply command value [Acurrent] continues to differ from the inert gas supply command value [A] determined in command value determination step S4 for a period of "T1" seconds, it is determined that the flow rate boundary has been stably exceeded, and the command value of the MFC51a used for purging within the frame is updated to the inert gas supply command value [A] determined in command value determination step S4. This is to avoid an unstable automatic pressure control situation caused by fluctuations in the inert gas flow rate due to fluctuations in the oxygen concentration value at the boundary of the switching between the inert gas supply rate and the oxygen concentration.

[0073] If the state of the inert gas supply command value [A] being different from the current inert gas supply command value [Acurrent] has lasted for "T1" seconds, the inert gas supply command value for the MFC51a used for purging the housing is updated, the final update of the inert gas supply command value is completed, and the flow control of the MFC51a used for purging the housing is implemented based on the updated inert gas supply command value. Then, the above steps are repeated until a predetermined time point or a predetermined processing completion time point has elapsed. In this embodiment, when updating the inert gas supply command value, that is, when updating the command value determined in the command value determination step S4 to the latest inert gas supply command value, the change is performed gradually over a predetermined time. Specifically, after transitioning to the above-mentioned additional oxygen concentration control transport mode, the inert gas supply command value is updated at [F2] LPM / sec; when transitioning to the additional oxygen concentration control transport mode, the inert gas supply command value is updated at [F1] LPM / sec. In this embodiment, [F2] is set to a value relatively smaller than [F1], and the change per second (LPM / sec) when updating the inert gas supply command value is set to be relatively small. Therefore, after switching to the supplemental oxygen concentration control transport mode, the change is performed relatively slowly compared to the transition to the supplemental oxygen concentration control transport mode. For example, after switching to the supplemental oxygen concentration control transport mode, when the inert gas supply command value is changed (updated) from 200 LPM to 150 LPM, that is, when the flow rate setting value of the MFC51a used for purging the housing is reduced by 50 LPM, the flow rate is gradually changed at a rate of 2 LPM per second for a total of 25 seconds, so that the pressure inside the housing 2 does not change drastically, and the opening of the discharge valve of the discharge pipe 22d is changed according to the inert gas supply.

[0074] Thus, according to the EFEM1 of this embodiment, the amount of inert gas supplied to the frame 2 is set based on the oxygen concentration inside the frame 2. When the bottom purging process performed by the bottom purging device 36 is performed with the container door 43 open (when the determination result of the door opening and bottom purging determination unit 12 is "yes"), the amount of inert gas supplied in the bottom purging process (bottom purging inert gas supply amount) is subtracted from the total amount of inert gas supplied. Based on this subtraction value, the command value for the amount of inert gas supplied to the frame 2, namely the inert gas supply amount command value, is determined. The amount of inert gas supplied to the frame 2 is controlled based on the inert gas supply amount command value. Therefore, considering the amount of inert gas supplied during the bottom purging process, it can be controlled in a way that does not exceed the upper limit of the gas supply to the entire EFEM1 (the total amount of inert gas supplied based on the oxygen concentration in the housing 2). This avoids the waste of inert gas, such as the discharge of inert gas from the housing 2 even though the oxygen concentration has not changed. It can save inert gas and always keep the pressure in the housing 2 of EFEM1 at a slightly positive pressure with a predetermined amount of gas used.

[0075] In particular, in the EFEM1 according to this embodiment, during the execution of inert gas supply control to the frame 2, when changing the inert gas supply amount to the frame 2 to the inert gas supply amount command value determined based on the calculation result of the inert gas supply amount calculation unit 13 in the frame (when updating the inert gas supply amount command value determined based on the calculation result of the inert gas supply amount calculation unit 13 in the frame to the latest inert gas supply amount command value), the control is performed in a manner that takes a predetermined time to gradually change, thereby preventing and suppressing rapid pressure changes in the frame 2.

[0076] Furthermore, in this embodiment, the EFEM1 includes either a structure that supplies inert gas to the interior of the substrate transport robot R disposed in the substrate transport space 2Sa (inert gas supply device (ejector R8, inert gas purging device R9) or a structure that includes an ionization device 8 that locally supplies inert gas to a predetermined portion of the substrate placed in the substrate transport space 2Sa to perform substrate de-electrolysis, the inert gas supply amount is also taken into consideration and the inert gas supply amount command value is calculated and determined. Therefore, it is possible to control the gas supply amount in a manner that does not exceed the upper limit of the gas supply amount to the entire EFEM1 (the total amount of inert gas supplied based on the oxygen concentration in the frame 2), which avoids the waste of inert gas and keeps the pressure inside the frame 2 of the EFEM1 at a slightly positive pressure with a predetermined usage amount.

[0077] Furthermore, the inert gas supply control method of this embodiment, as described above, is based on an instruction value determined through the inert gas supply total amount setting step S1, the door opening and bottom purging determination step S2, the inert gas supply amount calculation step S3, and the instruction value determination step S4. This method controls the inert gas supply amount to the frame 2, thus avoiding the situation where nitrogen gas exceeding the initial control amount is supplied to the frame 2, saving nitrogen gas, and maintaining the pressure inside the frame 2 of EFEM1 at a slightly positive pressure at a predetermined usage amount.

[0078] The embodiments of the present invention have been described above, but the present invention is not limited to the structure of the above embodiments. For example, the parameters of the oxygen concentration control table shown in the above embodiments are just examples, and the specific values ​​and preset values ​​of the parameters can be appropriately changed and selected.

[0079] In the above embodiments, FOUP is used as the substrate storage container. However, in this invention, other storage containers besides FOUP can also be used, such as MAC (Multi Application Carrier), H-MAC (Horizontal MAC), FOSB (Front Open Shipping Box), etc.

[0080] In the above embodiments, nitrogen is used as an inert gas for bottom purging processes, but it is not limited to this; dry gas, argon, or other desired gases can be used.

[0081] In the above embodiment, a structure with three loading ports connected to the front wall of the transport chamber is illustrated, but a structure with fewer than three or more loading ports can also be used.

[0082] Furthermore, the specific structure of each part is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0083] 1: Front-end Device Module (EFEM) 11: Inert Gas Supply Total Quantity Setting Department 12: Door opening and purge determination unit (door opening and bottom purge determination unit) 13: Inert gas supply calculation unit inside the frame 14: Instruction Value Determination Unit 1C: Control Unit 2: Frame 2a: Front surface wall 2b: Back wall 2e: Oxygen concentration meter 2g: Hygrometer 2f: Pressure gauge 21: Loop Path 22: Return path 22a: Opening 22b: Fan 22c: partition wall 22d: Discharge pipe 23: Fan Filter Unit (FFU) 2Sa: Substrate handling space 2Sb: FFU setup space 3: Loading port 31: Opening 32: Framework 33: Loading port 34: Door opening and closing mechanism 35: Platform 351: Horizontal base 36: Bottom purging device 37: Purge nozzle 3C: Control Unit 4: FOUP (Foundry-on-Pack) 41: Moving in and out 42: FOUP main body 43: FOUP Gate (Container Gate) 44: Flange portion 4S: Interior Space 50: Supply Source 51: Supply Path 51a: Mass Flow Controller (MFC) 51b: Supply valve 52: Secondary Supply Path 52a: Flow meter 52b: Supply valve 53: Supply Path 53a: Flow meter 53b: Supply valve 531: Attraction Path 54: Supply Path 54b: Supply valve 55: Supply Path 55a: Flow meter 55b: Supply valve 60: Supply Source 61: Supply Path 61a: Mass Flow Controller (MFC) 61b: Supply valve 7: Aligner 71: Alignment Platform 72: Align with the frame 73: Through-pass 74: Connection Path 75: Fan 8: Ionization device S1, S2, S3, S4: Steps M: Processing device MC: Control Department MS: Internal Space R: Baseboard handling robot R1:Abutment part R1a: Internal space R2: Arm R3, R4, R5: Arm components R3a, R4a, R5a: Internal space R6: Robotic Hand R7: Cylinder Block R8: Injector R9: Internal blowing device for handling robot R11: Export R12: Connection Path R13: Fan W: substrate

[0084] none

Claims

1. A device front-end module (EFEM) comprising: a frame having an internally enclosed substrate transport space; and a control unit for controlling at least the supply of an inert gas into the frame, wherein the control unit comprises: an inert gas supply total amount setting unit for setting the total amount of inert gas supplied into the frame based on the oxygen concentration in the frame. The unit includes a door opening and purging determination section, which determines, for each loading port adjacent to the frame, whether the container door of the substrate storage container placed on the mounting platform capable of holding the substrate storage container is open, and whether it is undergoing purging processing by a purging device capable of replacing the gas atmosphere inside the substrate storage container placed on the mounting platform with inert gas; and a frame inert gas supply amount calculation section, which, if the determination result of the door opening and purging determination section is yes, calculates the inert gas supply amount to the frame based on the value obtained by subtracting the inert gas supply amount (i.e., the inert gas supply amount inside the container) from the total inert gas supply amount set by the inert gas supply amount setting section. The control unit is configured to control the amount of inert gas supplied to the frame by using an inert gas supply command value determined based on the calculation result of the inert gas supply amount calculation unit within the frame.

2. The EFEM as described in claim 1, wherein when changing the inert gas supply amount to the housing to an inert gas supply amount command value determined based on the calculation result of the inert gas supply amount calculation unit in the housing, the control is performed in a manner that gradually changes the amount over a predetermined time.

3. The EFEM as claimed in claim 1 or 2, wherein the EFEM includes an inert gas supply device inside the substrate handling robot that supplies inert gas to the interior of the substrate handling robot disposed in the substrate handling space, and wherein the EFEM is configured such that, when the inert gas supply device inside the handling robot is in an inert gas supply state, the inert gas supply amount calculation unit inside the frame calculates the inert gas supply amount inside the frame based on a value obtained by subtracting at least the inert gas supply amount of the inert gas supply device inside the handling robot and the inert gas supply amount inside the container from the total inert gas supply amount set by the total inert gas supply amount setting unit.

4. The EFEM as claimed in claim 1 or 2, wherein the EFEM includes an ionization device for removing charge from a substrate by locally supplying an inert gas to a predetermined portion of the substrate placed in the substrate transport space, and the EFEM is configured such that, when the ionization device is in an inert gas supply state, the inert gas supply amount calculation unit within the housing calculates the amount of inert gas supplied to the housing based on a value obtained by subtracting at least the inert gas supply amount of the ionization device and the inert gas supply amount within the container from the total inert gas supply amount set by the total inert gas supply amount setting unit.

5. A method for controlling the supply of inert gas to a housing within a device front-end module (EFEM), the EFEM comprising: the housing, which includes a substantially enclosed substrate transport space inside; and a control unit for controlling the supply of inert gas to the housing, wherein, The inert gas supply control method includes: an inert gas supply total amount setting step; a door opening and purging determination step; an inert gas supply amount calculation step within the frame; and a step of controlling the inert gas supply amount. The inert gas supply total amount setting step sets the total inert gas supply to the frame based on the oxygen concentration within the frame. The door opening and purging determination step determines, for each loading port adjacent to the frame, whether the container door of the substrate storage container placed on the loading port's mounting platform is open and whether it is undergoing purging processing by a purging device capable of replacing the gas atmosphere within the substrate storage container placed on the mounting platform with inert gas. The inert gas supply calculation step within the frame is performed when the door opening and purging determination step is successful. The calculation is based on the value obtained by subtracting the inert gas supply amount from the purging device at the loading port to the substrate receiving container (i.e., the inert gas supply amount within the container) from the total inert gas supply amount set in the inert gas supply total amount setting step. Furthermore, the inert gas supply control step controls the inert gas supply amount within the frame based on the calculation result from the inert gas supply calculation step within the frame.

Images