JP7545068B2 - Transport room - Google Patents

Description

The present invention relates to a transport chamber that can transport objects in a clean state without exposing them to the outside air.

Traditionally, in the semiconductor field, semiconductor devices have been manufactured by subjecting wafers to various processing steps.

In the semiconductor device manufacturing process, a particle-free and chemical component-free wafer transport environment is required, and a transport chamber generally called an EFEM (Equipment Front End Module) is used to transfer wafers between a sealed container called a FOUP (Front-Opening Unified Pod) and a processing device (see Patent Document 1 below). In the transport chamber, a constant clean atmosphere can be stably obtained by drawing in fresh outside air from the clean room using an FFU (Fun Filter Unit) installed at the top, and then causing it to flow down through the interior and be discharged to the outside from the floor.

Furthermore, in recent years, as semiconductor device structures become finer, the effects of moisture, oxygen, chemical components, etc. have become a growing concern, and in response to these issues, it has been proposed to replace the inside of the transfer chamber with N2 (nitrogen) gas, an inert gas, and transfer the wafers in an N2 atmosphere. In this case, in order to reduce the consumption of N2 gas and keep running costs down, it is necessary to maintain internal cleanliness while reducing the supply of fresh N2 gas, so it is conceivable to circulate the N2 gas through a filter.

In addition, it is also possible to provide a chemical filter to efficiently remove chemical components from the circulating N2 gas. Chemical components may be brought into the transfer chamber by wafers processed by the processing equipment, so the chemical filter can be used to efficiently remove such chemical components and maintain an even cleaner atmosphere.

JP 2012-49382 A

When circulating gas inside the transfer chamber as described above, the gas return space becomes important.

Furthermore, when circulating gas inside the transfer chamber as described above, the fan becomes important.

The present invention aims to provide a transport chamber that can transport objects in a clean environment.

To achieve this objective, the present invention takes the following measures:

That is, the transfer chamber of the present invention is a transfer chamber with a sealed interior for transferring transported objects to and from a processing device using a transfer robot provided inside, and has a front wall to which a load port is connected, a rear wall having an opening to which a load lock chamber constituting a part of the processing device is connected, a first fan that forms a downward air flow in the transfer space, and a gas return space provided on the rear wall side for circulating the air flow that has flowed downward through the transfer space above the first fan, and the gas return space has second fans provided on both sides of the opening inside the transfer chamber and forming an upward air flow in the gas return space .

It is preferable that two gas return spaces are provided.

It is also preferable that the second fan be located below a wafer transfer portion of an opening provided in the front wall on the load port side .

It is preferable that a plurality of the second fans are provided, and the plurality of second fans are disposed respectively with respect to the gas return space.

It is preferable that the suction port of the gas return space is disposed above the bottom surface of the transfer chamber.

It is preferable that the gas treatment device further comprises a gas treatment box for purifying the gas circulating within the transfer chamber, and the gas in the transfer space enters the gas return space through an intake port of the gas return space, is converted into an ascending air current by the second fan, passes through the gas treatment box, and is converted into a descending air current by the first fan and circulated to the transfer space.

According to the present invention described above, it is possible to circulate clean gas inside along the circulation path.

FIG. 2 is a plan view illustrating a relationship between a transfer chamber and a processing apparatus according to the embodiment of the present invention. FIG. FIG. 2 is a cross-sectional view of the transfer chamber taken along the line AA in FIG. FIG. 4 is a cross-sectional view of the transfer chamber taken along the line BB in FIG. 3 . FIG. 2 is a block diagram illustrating a configuration for controlling the internal atmosphere of the transfer chamber.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 is a plan view showing a schematic diagram of the relationship between a transfer chamber 1 according to an embodiment of the present invention and a processing device 6 connected thereto. As shown in this figure, the transfer chamber 1 is configured as a modular device generally called an EFEM. Specifically, the transfer chamber 1 is composed of a transfer robot 2 that transfers the wafer W, which is the object to be transferred, between predetermined transfer positions, a box-shaped housing 3 that is provided to surround the transfer robot 2, and multiple load ports 4-4 (three in the figure) that are connected to the outside of the front wall (front wall 31) of the housing 3.

In this application, the direction toward the side to which the load ports 4-4 are connected as viewed from the housing 3 is defined as the front, the direction toward the rear wall 32 side facing the front wall 31 is defined as the rear, and further, the direction perpendicular to the front-rear direction and the vertical direction is defined as the side. In other words, the three load ports 4-4 are arranged side by side.

As shown in FIG. 1, the transfer chamber 1 is adjacent to the outside of the rear wall 32, and a load lock chamber 61 constituting a part of the processing device 6 can be connected to the transfer chamber 1, and the inside of the transfer chamber 1 and the load lock chamber 61 can be communicated by opening a door 1a provided between the transfer chamber 1 and the load lock chamber 61. Various types of processing device 6 can be used, but in general, a relay chamber 62 is provided adjacent to the load lock chamber 61, and a plurality of processing units 63-63 (three in the figure) that process the wafer W are provided adjacent to the relay chamber 62. Doors 62a, 63a-63a are provided between the relay chamber 62 and the load lock chamber 61 and the processing units 63-63, respectively, and these doors can be opened to communicate with each other, and the wafer W can be moved between the load lock chamber 61 and the processing units 63-63 using a transfer robot 64 provided in the relay chamber 62.

Figure 2 is a perspective view of the transfer chamber 1 as seen from the load port 4 side, and Figure 3 shows a cross section of the transfer chamber 1 at position A-A in Figure 1.

As shown in Figures 2 and 3, the housing 3 that constitutes the transfer chamber 1 is composed of a main body box 3A, a chemical filter box 3B, and a control box 3C, and the main body box 3A constitutes the transfer chamber main body 1A together with the internal transfer robot 2 (see Figure 1) and the load ports 4-4 provided on the front wall 31. Furthermore, the main body box 3A, the chemical filter box 3B, and the control box 3C are separable from each other.

The front wall 31, rear wall 32, left side wall 33, and right side wall 34 of the housing 3 are respectively formed by the front walls 31A, 31B, and 31C, rear walls 32A, 32B, and 32C, left side walls 33A, 33B, and 33C, and right side walls 34A, 34B, and 34C of the main box 3A, chemical filter box 3B, and control box 3C. The top wall 35 of the housing 3 is formed by the top wall 35C of the control box 3C, and the bottom wall 36 of the housing 3 is formed by the bottom wall 36A of the main box 3A. The bottom wall 36B of the chemical filter box 3B abuts against the top wall 35A of the main box 3A, and the bottom wall 36C of the control box 3C abuts against the top wall 35B of the chemical filter box 3B, and are fixed to each other in that state.

The load port 4 is connected to the opening 31a provided in the front wall 31A of the main body box 3A, and the rectangular opening 32a (see FIG. 1) provided in the back wall 32A is closed by a door 1a generally called a gate valve. In addition, two openings 35A1 and 35A2 are provided in the top wall 35A of the main body box 3A, and openings 36B1 and 36B2 are also provided in the bottom wall 36B of the chemical filter box 3B at positions corresponding to these openings, so that the space S1 in the main body box 3A and the space S2 in the chemical filter box 3B are connected to each other, forming one substantially sealed space CS.

The transport robot 2 provided in the space S1 in the main box 3A is composed of an arm 2a equipped with a pick on which a wafer W is placed and transported, and a base 2b supporting the arm 2a from below and having a drive mechanism and lifting mechanism for operating the arm 2a. The base 2b is supported on the front wall 31A of the main box 3A via a support 21 and a guide rail 22. The transport robot 2 can move along the guide rail 22 extending in the width direction inside the main box 3A, and the control means 5 described later controls the operation of the transport robot 2 to transport the wafer W contained in the FOUP 41 placed on each load port 4-4 to the load lock chamber 61, and to transport the wafer W after processing in each processing unit 63-63 back into the FOUP 41.

Inside the chemical filter box 3B, there is a chemical filter unit 7, which is generally known as a chemical filter. The chemical filter unit 7 is composed of an organic removal filter 71 for removing organic components from the chemical components contained in the gas passing through it, an acid removal filter 72 for removing acid components, and an alkali removal filter 73 for removing alkali components, and each of the filters 71 to 73 can be replaced independently.

Inside the control box 3C, there is provided a control means 5, which is a control unit for controlling the entire transport chamber main body 1A. The control means 5 is composed of a normal microprocessor equipped with a CPU, memory, and interface, and the programs required for processing are stored in advance in the memory. The CPU sequentially retrieves and executes the necessary programs, working with peripheral hardware resources to achieve the desired functions. As described below, the control means 5 controls the operation of the transport robot 2 and load port 4 in the main box 3A, the opening and closing of each door 1a, 4a, and the supply of gas into the main box 3A and chemical filter box 3B.

As shown in FIG. 3, the space S1 in the main box 3A is divided by an internal wall 37A extending from the bottom wall 36A to the top wall 35A into a transport space S11, where the transport robot 2 operates, and a gas return space S12. An opening 37A1 is provided at the bottom of the internal wall 37A, and the transport space S11 and the gas return space S12 communicate with each other on the lower side through this opening 37A1. Furthermore, a fan 77 is provided at the bottom of the gas return space S12, continuous with the opening 37A1, and by driving this fan 77, gas in the transport space S11 can be taken into the gas return space S12, creating an upward air current in the gas return space S12.

Here, FIG. 4 is a cross-sectional view taken along the line B-B in FIG. 3. As can be seen from this figure, a wall 38A is formed in the center of the gas return space S12, surrounding the door 1a between the gas return space S12 and the load lock chamber 61 (see FIG. 1), and the space around the door 1a is continuous with the transfer space S11 (see FIG. 3). Therefore, the gas return space S12 is configured to split into two branches from below to avoid the door 1a, and then reunite at the top.

Returning to FIG. 3, the transfer space S11 and the gas return space S12 are connected to the space S2 in the chemical filter box 3B via the openings 35A1 and 35A2 in the upper wall 35A described above. Therefore, the transfer space S11 and the gas return space S12 are also connected to each other on the upper side via the space S2 in the chemical filter box 3B.

An FFU 76 is provided at the top of the transfer space S11, specifically at a position slightly below the top wall 35A, and the gas taken in from the space S2 in the chemical filter box 3B is sent downward by the FFU 76, forming a downflow in the transfer space S11. Furthermore, the FFU 76 is equipped with high-performance filters such as a HEPA (High Efficiency Particulate Air) filter and a ULPA (Ultra Low Penetration Air) filter, making it possible to capture minute particles contained within the gas passing through.

On the other hand, in the chemical filter box 3B, a discharge fan 75 is provided between the opening 36B1 of the bottom wall 36B and the chemical filter unit 7, and a suction fan 76 is provided above the opening 36B2. The opening 36B2 and the opening 35A2 connected thereto function as gas inlets that allow gas to flow toward the chemical filter unit 7, and the suction fan 76 allows gas to flow from the gas return space S12 into the chemical filter box 3B through these openings 36B2 and 35A2. The opening 36B1 and the opening 35A1 connected thereto function as gas outlets that allow gas to be discharged from the chemical filter unit 7, and the discharge fan 75 can send the gas that has passed through the chemical filter unit 7 into the transfer space S11 through these openings 35B1 and 35A1. Therefore, the two fans 75 and 76 can compensate for the pressure loss caused by the chemical filter unit 7 and create a gas flow.

As described above, in the substantially sealed space CS formed in the main box 3A and the chemical filter box 3B, the gas constituting the internal atmosphere circulates along the circulation path CL as follows. That is, the circulation path CL advances downward from the FFU 76 provided at the top of the transfer space S11, then advances upward through the gas return space S12 through the opening 37A1 and the fan 77 provided at the bottom of the internal wall 37A, passes through the openings 35A2 and 36B2, enters the space S2 in the chemical filter box 3B via the suction fan 74, passes through the chemical filter unit 7, and returns to the transfer space S11 through the discharge fan 75 and the openings 36B1 and 35A1. Therefore, it can be said that the chemical filter unit 7 is provided midway along the circulation path CL.

To supply N2 gas to purge the substantially sealed space CS in which the circulation path CL is formed, a gas supply port 91 is provided in the rear wall 32B of the chemical filter box 3B, and a gas exhaust port 92 is provided in the rear wall 32A of the main body box 3A.

As shown in FIG. 5, a gas supply line GS and a gas exhaust line GE are connected to the gas supply port 91 and the gas exhaust port 92, respectively.

The gas supply line GS is equipped with a gas supply means NS, which is configured by piping leading from an N2 gas supply source, which is provided with a regulator 93, a valve 94, an MFC (gas flow controller) 95, and another valve 94 in that order.

The gas exhaust line GE is provided with a flow rate control valve 98 and a valve 94 in that order in the piping connected to the gas exhaust port 92A, and the gas exhaust destination is connected to the end of the valve.

Therefore, by supplying N2 gas from the gas supply port 91 while discharging gas from the gas exhaust port 92, the air in the substantially sealed space CS can be removed and filled with N2 gas.

When the concentration of N2 gas reaches a certain level, the amount of N2 gas supplied from the gas supply port 91 is reduced while the amount of gas discharged from the gas exhaust port 92A is made small, so that the inside is kept at a positive pressure. In this state, the internal gas is circulated along the circulation path CL, so that particles and chemical components contained in the gas are removed by the FFU 76 and chemical filter unit 7, and the inside can be kept clean. In addition, since N2 gas is a dry gas that contains almost no moisture, it is also possible to reduce the moisture inside and prevent corrosion of the surface of the wafer W.

However, by continuing to supply N2 gas to replace the internal atmosphere as described above, the amount of moisture inside may become too low, which may reduce the ability of the chemical filter unit 7 to remove chemical components.

As shown in FIG. 3, the chemical filter unit 7 is made up of an organic removal filter 71, an acid removal filter 72, and an alkali removal filter 73. The organic removal filter 71 removes organic components by adsorption, while the acid removal filter 72 and the alkali removal filter 73 remove acid and alkali components by hydrolysis. Therefore, a certain amount of moisture is required to remove acid and alkali components, and if the humidity in the gas becomes too low, the removal performance drops significantly.

Therefore, in this embodiment, in order to keep the internal humidity constant, the following moisture supply means HS is provided so that the N2 gas supplied from the gas supply means NS can contain moisture.

The moisture supply means HS is composed of a valve 94 connected to a pipe connected to a water supply source, an LFC (liquid flow controller) 99 as a flow control unit, the valve 94, a sprayer 96 generally called an injector, a vaporizer 97, and a heater controller 97b that operates a heater 97a included in the vaporizer 97.

Specifically, a valve 94, an LFC 99, and a valve 94 are connected in sequence to a pipe connected to a water supply source, and the pipe is further connected to a sprayer 96 provided in the middle of the gas supply line GS. Therefore, the amount of moisture to be added can be determined by adjusting the flow rate of water with the LFC 99, and the water can be made into a fine mist by the sprayer 96 and contained in the N2 gas. And downstream of the sprayer 96, a vaporizer 97 consisting of a coiled pipe and a heater 97a for heating the pipe is provided. The heater 97a is supplied with power by a heater controller 97b, so that it can heat the gas flowing through the pipe and vaporize the water particles contained therein. Furthermore, a heat insulation means HI consisting of a pipe insulation material and a heater for heat insulation is provided on the pipe constituting the gas supply line GS from the sprayer 96 to the gas supply port 91 via the vaporizer 97, so that the moisture once vaporized does not condense and flow into the chemical filter box 3B as water droplets.

The gas supply means NS and moisture supply means HS cooperate to form a gas and moisture supply means NHS for supplying moisture-containing N2 gas into the substantially sealed space CS.

To control the gas and moisture supply means NHS, humidity detectors HG1 and HG2 are provided in the space S1 in the main box 3A and the space S2 in the chemical filter box 3B, respectively, as humidity detection means for detecting humidity. Furthermore, a pressure detector PG is provided as pressure detection means for detecting the pressure difference between the space S1 in the main box 3A and the outside.

The above-mentioned control means 5 has the following configuration to control the gas supply means NS based on the detected values.

The control means 5 includes a gas (N2) flow rate determination unit 51, a water (H2O) flow rate determination unit 52, a heater operation command unit 53, a pressure acquisition unit 54, a humidity acquisition unit 55, and a memory unit 56.

The memory unit 56 stores a pressure target value and a humidity target value, which are predetermined values. The pressure acquisition unit 54 acquires the output from the pressure detector PG and can output it as a pressure detection value. The humidity acquisition unit 55 acquires the output from the humidity detectors HG1 and HG2 and can output them as humidity detection values.

The gas flow rate determination unit 51 is configured to determine the flow rate of N2 gas supplied from the gas supply line GS based on the pressure detection value obtained by the pressure acquisition unit 54, and output a corresponding gas flow rate command value to the MFC 95. More specifically, if the pressure detection value is within a predetermined range centered on the pressure target value, the gas flow rate command value is maintained as is, if the pressure detection value is smaller than the above-mentioned predetermined range, the supply amount of N2 gas is increased, and if the pressure detection value is larger than the above-mentioned predetermined range, the gas flow rate command value is changed so as to decrease the supply amount of N2 gas.

The water flow rate determination unit 52 is configured to determine the flow rate of water supplied from the water supply means HS based on the humidity detection value by the humidity detector HG2 obtained through the humidity acquisition unit 55, and output the corresponding water flow rate command value to the LFC 99. More specifically, when the humidity detection value is within a predetermined range centered on the humidity target value, the water flow rate command value is maintained as is, when the humidity detection value is smaller than the above-mentioned predetermined range, the water supply amount is increased, and when the humidity detection value is larger than the above-mentioned predetermined range, the water flow rate command value is changed so as to decrease the water supply amount. Note that when the humidity detection value is larger than the humidity target value, the water supply amount may be set to zero and only N2 gas may be supplied. For such humidity control, it is also preferable to suppress overshoot and hunting by using PID control. Note that when performing the above control, the humidity detection value by the humidity detector HG1 is used for monitoring, but the humidity detection value by the humidity detector HG2 may be used for monitoring and the humidity detection value by the humidity detector HG1 may be used for control.

The heater operation command unit 53 is configured to give a command to the heater controller 97b to operate the heater 97a in accordance with the water flow command value determined by the water flow determination unit 52.

By configuring the transport chamber 1 as described above, it can be operated as follows.

First, when the operation of the transfer chamber 1 is started, as shown in FIG. 5, N2 gas is supplied from the gas supply port 91 through the gas supply line GS to the internal approximately sealed space CS, while air is removed from the gas exhaust port 92 through the gas exhaust line GE, and purging with N2 gas is performed. At this time, the pressure acquisition unit 54 acquires a pressure detection value from the output obtained from the pressure detector PG, and the gas flow rate determination unit 51 determines a gas flow rate command value based on this pressure detection value and outputs it to the MFC 95. Then, the MFC 95 adjusts the gas flow rate according to the gas flow rate command value, thereby changing the flow rate of N2 gas supplied to the approximately sealed space CS. In this way, the inside of the approximately sealed space CS can be kept at a positive pressure higher than the outside, and the intrusion of particles from the outside can be prevented.

Furthermore, the control means 5 can operate the FFU 76 and fans 74, 75, and 77 to circulate the gas inside along the circulation path CL, and the chemical filter unit 7 and FFU 76 can remove particles and chemical components contained in the gas to create a clean state.

Furthermore, the humidity acquisition unit 55 constituting the control means 5 acquires a humidity detection value from the output obtained from the humidity detector HG2, and the water flow rate determination unit 52 determines a water flow rate command value based on this humidity detection value and outputs it to the LFC 99. The LFC 99 adjusts the water flow rate according to the water flow rate command value, thereby adjusting the amount of moisture contained in the N2 gas supplied to the approximately sealed space CS. In addition, the moisture is provided as fine particles by the sprayer 96, and then vaporized by the downstream vaporizer 97 and provided into the chemical filter box 3B. In this way, a slight humidity level that does not impair the hydrolysis reaction by the chemical filter unit 7 can be maintained in the approximately sealed space CS, effectively removing chemical components and preventing corrosion of the wafer W due to excessive humidity.

By purifying the internal atmosphere as described above, the system transitions to a normal state in which the supply of N2 gas is reduced while maintaining a positive pressure in the substantially sealed space CS, thereby reducing the consumption of N2 gas. Then, by operating the transfer robot 2, the load ports 4-4 shown in FIG. 1, and the doors 1a, 4a-4a using the control means 5, the wafer W to be transferred can be transferred while maintaining a clean state.

Furthermore, even during normal operation, humidity control based on the humidity detection value from the humidity detector HG2 is continued, so that the removal performance of the chemical filter unit 7 can be maintained. Even if chemical components flow in from the processing device 6 together with the wafer W, these can be appropriately removed to keep the interior clean.

As described above, the transfer chamber 1 in this embodiment is used to transfer the wafer W as the object to be transferred between the processing device 6 side and the transfer robot 2 installed inside, and is equipped with a circulation path CL formed inside to circulate gas, a chemical filter unit 7 as a chemical filter installed midway along the circulation path CL, a humidity detector HG2 as a humidity detection means for detecting the humidity inside, a gas supply means NS for supplying gas to the inside, and a moisture supply means HS for supplying moisture to the inside, and is configured to operate the moisture supply means HS based on the humidity detection value by the humidity detection means.

When circulating gas inside the transfer chamber, it is almost impossible to discharge the chemical components brought in from the processing equipment to the outside, so it becomes necessary to remove them more efficiently using a chemical filter. Since the chemical filter involves a removal mechanism that utilizes a hydrolysis reaction for acid and alkaline components, if the humidity is made too low, it becomes difficult to remove the acid and alkaline components. Since the N2 gas supplied to the transfer chamber usually contains almost no moisture, there is a risk that the humidity inside the transfer chamber will become low and the chemical components will not be removed sufficiently. However, in the above embodiment, the humidity inside the transfer chamber can be kept at an appropriate level by operating the moisture supply means HS based on the humidity detection value by the humidity detector HG2, so that the chemical filter unit 7 can appropriately perform a hydrolysis reaction, remove the chemical components, and keep the inside clean. Therefore, it is possible to transfer the wafer W while maintaining a clean state, and the yield of semiconductor devices manufactured using the wafer W can be improved.

Furthermore, the moisture supply means HS is configured to add moisture to the gas midway along the gas supply line GS from the gas supply means NS, making it possible to supply moisture more stably.

The moisture supply means HS is composed of an LFC99 as a flow control unit connected to a moisture supply source, a sprayer 96 that sprays the water supplied from the LFC99 into the gas, and a vaporizer 97 that vaporizes the water sprayed into the gas, making it possible to easily and appropriately control the amount of moisture supplied.

In addition, the gas supply line GS downstream of the moisture supply by the moisture supply means HS is configured to be provided with a heat insulation means HI for keeping the piping warm. This prevents the gas temperature from dropping below the dew point after the moisture supply by the moisture supply means HS, which would otherwise cause condensation, making it possible to prevent excess moisture from entering while maintaining an appropriate internal humidity level.

The specific configuration of each part is not limited to the above-mentioned embodiment.

For example, in the above embodiment, N2 gas was used as the gas to fill the interior, but Ar (argon) gas, which is also an inert gas, can also be used. Furthermore, anything other than N2 gas or Ar gas can be used as long as it is other than water gas, i.e., water vapor, and can be changed as appropriate depending on the processing content of the wafer W, which is the object to be transported.

This transfer chamber 1 can also be used to transfer objects other than wafers W.

In addition, in the above-described embodiment, the moisture supplying means HS is configured to supply moisture to the N2 gas supplied to the substantially sealed space CS, but it can also be configured to supply moisture directly into the substantially sealed space CS, and in that case, the same effect as above can be obtained.

Furthermore, in the above embodiment, the moisture supply means HS is operated based on the detection value by the humidity detector HG2 to maintain the substantially sealed space CS at a desired humidity level, but it may be configured so that a predetermined amount of moisture is supplied from the moisture supply means HS every predetermined time without using the detection value by the humidity detector HG2. This also makes it possible to maintain the substantially sealed space CS at a desired humidity level, and to obtain effects similar to those described above. In addition, by eliminating the need for the humidity detector HG2, it is possible to further reduce manufacturing costs.

Other configurations can also be modified in various ways without departing from the spirit of the present invention.

REFERENCE SIGNS LIST 1: Transport chamber 2: Transport robot 5: Control means 6: Processing device 7: Chemical filter unit (chemical filter)
96: sprayer 97: vaporizer 99: LFC (flow rate control unit)
CL: Circulation path GE: Gas exhaust line GS: Gas supply line HS: Moisture supply means HG1, HG2: Humidity detector (humidity detection means)
HI: Heat retention means NS: Gas supply means W: Wafer (carried object)

Claims (6)

A transport chamber having a sealed interior for transferring a transported object between a processing device and the transport chamber using a transport robot provided therein,
a front wall to which the load port is connected;
a rear wall having an opening to which a load lock chamber constituting a part of the processing apparatus is connected;
A first fan that forms a downward airflow in the transfer space;
a gas return space provided on the rear wall side and configured to circulate the airflow that has flowed downward through the transfer space to above the first fan,
the gas return spaces are provided on both sides of the opening in the transfer chamber ,
a second fan for forming an upward air flow in the gas return space ;
The transfer chamber according to claim 1 , wherein two gas return spaces are provided. 3. The transfer chamber according to claim 1, wherein the second fan is located below a wafer transfer portion of an opening provided in a front wall on the load port side . The second fan is provided in plurality,
4. The transfer chamber according to claim 1, wherein the second fans are disposed relative to the gas return space. The transfer chamber according to any one of claims 1 to 4, characterized in that the suction port of the gas return space is located above the bottom surface of the transfer chamber. The gas treatment device further includes a gas treatment box for purifying the gas circulating in the transfer chamber.
The transfer chamber according to any one of claims 1 to 4, wherein the gas in the transfer space enters the gas return space through an intake port of the gas return space, is converted into an ascending air current by the second fan, passes through the gas processing box, and is converted into a descending air current by the first fan and circulated to the transfer space.

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