JP7206669B2 - Circulating EFEM - Google Patents

Description

The present invention relates to a circulating EFEM that circulates a gas such as nitrogen within a housing.

In a semiconductor manufacturing process, a device called an EFEM is used to transfer a substrate such as a silicon wafer. Substrates are transported in a factory using a container called a FOUP (FOUP) or the like. EFEM transports the substrate in the container to the processing equipment, and the substrate is processed in the processing equipment. Used to put the substrate back into the container. The EFEM includes a container mounting table called a load port device, a housing for forming a substrate transfer space for transferring the substrate, a transfer robot for transferring the substrate, and the like.

Here, the atmosphere in the substrate transfer chamber formed in the EFEM is kept clean in order to prevent harmful substances and particles from adhering to the transferred substrates and to prevent oxidation of the substrates. preferably The substrate transfer chamber may be filled with, for example, clean air that has been purified, but in order to reduce the frequency of contact of the substrate surface with oxygen or the like, it is better to fill the substrate transfer chamber with an inert gas such as nitrogen. preferable. Therefore, a circulating EFEM is proposed in which an inert gas such as nitrogen is introduced into the substrate transfer chamber and a gas containing the inert gas as a main component is circulated in the apparatus to maintain an inert atmosphere in the substrate transfer chamber. It is

JP 2015-146349 A

As a circulating EFEM, one having a discharge part for discharging gas such as nitrogen from the inside of the EFEM has been proposed. I have a problem that it is difficult to For example, there are cases where it is desired to change the amount of gas supplied into the EFEM according to the cleanliness of the substrate transfer chamber. is changed, problems such as an excessive change in the pressure in the substrate transfer chamber may occur. Further, in the conventional EFEM, when pressure changes occur in the discharge pipe, problems may occur such as the discharge flow rate becoming too high or too low.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a circulating EFEM capable of suitably adjusting the discharge flow rate of gas from the housing to the discharge pipe.

In order to achieve the above object, the circulating EFEM according to the present invention is
a gas introduction part for introducing gas;
a housing in which the introduced gas circulates;
an adjustment unit that adjusts discharge of the gas from the housing to a discharge pipe;
a first measurement unit provided in a flow path on the inner side of the housing from the adjustment unit and measuring at least one of flow rate and pressure of the gas;
a second measuring unit provided in the flow path on the side of the discharge pipe from the adjusting unit and measuring at least one of flow rate and pressure of the gas;
The adjustment unit adjusts the discharge of the gas using at least one of measurement results of the first measurement unit and the second measurement unit.

Since the circulating EFEM according to the present invention detects the conditions inside the housing and on the side of the discharge pipe by means of the first measurement unit and the second measurement unit, even when the flow rate and pressure inside the housing and on the side of the discharge pipe fluctuate, Even so, it is possible to appropriately adjust the discharge speed and discharge amount of the gas discharged from the housing.

Further, for example, the adjustment unit may adjust the discharge of the gas using measurement results of the first measurement unit and the second measurement unit.

Such an EFEM can adjust the discharge speed and discharge amount of the gas discharged from the housing more accurately and quickly. Emission adjustment such as arbitrarily changing the amount of discharge from is also possible with high accuracy.

Also, for example, the second measuring unit may measure a flow rate.

The first and second measurement units may measure at least one of the pressure and flow rate of the gas. can be directly measured and used to control the adjustment unit, and gas consumption can be managed with high accuracy.

Further, for example, the adjustment unit includes a valve element whose opening amount is determined based on the differential pressure between the inner side of the housing and the side of the discharge pipe with the adjustment unit interposed therebetween, the first measurement unit and the second and a coefficient changing unit that changes a coefficient that defines the relationship between the differential pressure and the opening amount using at least one of the measurement results of the measuring unit.

The adjustment unit may be a solenoid valve or the like that changes the opening amount according to the measurement results of the first measurement unit and the second measurement unit, but a mechanical valve body whose opening amount is determined according to the differential pressure and a coefficient changing unit that changes the coefficient that defines the relationship between the differential pressure and the release amount according to the measurement results of the first measuring unit and the second measuring unit.

FIG. 1 is a schematic diagram of an EFEM according to one embodiment of the present invention. FIG. 2 is a conceptual diagram showing the state of the EFEM and exhaust pipes in the semiconductor factory. FIG. 3 is a schematic cross-sectional view showing the internal structure of an adjustment section according to a modification.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a schematic cross-sectional view showing an EFEM (equipment front end module) 10 according to one embodiment of the present invention. The EFEM 10 is provided, for example, in association with various processing equipment (not shown) in a semiconductor factory, and processes a substrate 82 such as a silicon wafer housed in a FOUP (front-opening unified pod) 80, which is a transport container. It has a transport means for transporting to the apparatus and a housing 20 for forming a clean space (mini-environment or substrate transport chamber 22) through which substrates 82 during transport between the FOUP 80 and the processing apparatus pass.

The EFEM 10 includes a gas introduction part 16 that introduces gas such as inert gas and dry air (CDA) into the housing 20, a housing 20 in which the introduced gas circulates, and a discharge pipe 60 from the housing 20. It is a circulating EFEM with an adjustment section 30 that adjusts the discharge of gas to. Examples of the gas introduced into the housing 20 from the gas introduction part 16 and circulating in the housing 20 include dry air, nitrogen gas and other inert gases, and nitrogen gas is preferably used, but is not particularly limited. not.

The EFEM 10, for example, replaces the air in the housing 20 with nitrogen gas introduced from the gas introduction part 16, and is used in a state where the inside of the housing 20 is in a nitrogen gas atmosphere. The concentration of the nitrogen gas is not particularly limited, and gas other than the gas introduced from the gas introduction portion 16 of the housing 20, air, or the like may be included in the gas filling the housing 20 within an allowable range.

The EFEM 10 includes a load port device 70 having a loading table 72 on which the FOUP 80 is placed, a door (not shown) for opening the lid of the FOUP 80, and the like, in addition to the gas introduction unit 16, the housing 20, and the adjustment unit 30, and the housing 20. It has a fan filter unit 11 for forming a circulating airflow inside to remove harmful substances, particles, etc., and a substrate transport robot 26 as transport means for transporting the substrate 82 .

The load port device 70 is provided so as to form part of the sidewall of the housing 20 . The load port device 70 can airtightly connect the FOUP 80 mounted on the mounting table 72 to the housing 20 by horizontally moving the FOUP 80 . Furthermore, the load port device 70 can allow the inside of the FOUP 80 in which the substrate 82 is accommodated and the substrate transfer chamber 22 formed inside the housing 20 to communicate with each other by opening the lid of the FOUP 80 .

The substrate transfer robot 26 is installed on the floor surface of the substrate transfer chamber 22 inside the housing 20 and has an arm 26a for gripping and transferring the substrate 82 . The substrate transport robot 26 transports the substrates 82 in the FOUP 80 to a processing apparatus (more specifically, for example, a load lock chamber of the processing apparatus) to which the EFEM 10 is attached, or transports the substrates 82 that have been processed in the processing apparatus. For example, it is transported from the processing equipment into the FOUP 80 .

The fan filter unit 11 is provided in the housing 20 near the ceiling 20b. The fan filter unit 11 has a fan 12 provided on the ceiling 20 b inside the housing 20 and a filter 14 provided directly below the fan 12 . The fan 12 forms a downflow to the substrate transfer chamber 22 formed below the filter 14 . The fan 12 has, for example, blades inclined with respect to the rotation direction and a motor for rotating the blades, but is not particularly limited as long as it generates a predetermined airflow inside the housing 20 .

Filter 14 is provided directly below fan 12 . Although the filter 14 is not particularly limited, for example, a combination of a particle removal filter and a chemical filter can be used, and particles and contaminants present in the gas filling the housing 20 can be removed. Note that the fan filter unit 11 only needs to have a blower means such as the fan 12 and the filter 14, and the fan filter unit 11 includes a fan filter unit in which the blower means and the filter are arranged separately.

The housing 20 has a substantially rectangular parallelepiped outer shape, and a substrate transfer chamber 22 and a circulation flow path 24 are formed inside the housing 20 . Further, an intermediate wall 20d is provided inside the housing 20 to separate the substrate transfer chamber 22 and the circulation flow path 24. The circulation flow path 24 stands upright in the housing 20 and the load port device 70 is installed. Between the side wall 20a and the intermediate wall 20d, which are not provided, and between the ceiling 20b of the enclosure 20 and the filter 14 are formed.

The intermediate wall 20d shields an air flow of gas such as nitrogen gas, but a circulation gap 23 is formed between the intermediate wall 20d and the floor surface. Therefore, the substrate transfer chamber 22 and the circulation flow path 24 are connected via the filter 14 above the substrate transfer chamber 22 and are connected via the circulation gap 23 below the substrate transfer chamber 22 .

Since the filter 14 provided on the ceiling of the substrate transfer chamber 22 allows the airflow generated by the fan 12 to pass through, a downflow (downward airflow) is formed in the substrate transfer chamber 22 by the fan 12 provided on the ceiling. . In addition, the gas flows from the substrate transfer chamber 22 into the circulation channel 24 through the circulation gap 23 formed between the intermediate wall 20d and the floor surface, so that the circulation channel 24 except above the filter 14 is An ascending air current is formed from the circulation gap 23 toward the fan 12 in most part. In this way, the gas introduced from the gas introducing section 16 circulates inside the housing 20 .

That is, the EFEM 10 shown in FIG. 1 is used while forming a circulating gas flow as indicated by arrows in its housing 20 . Such an airflow of gas is formed by circulating the gas introduced into the housing 20 from the gas introduction part 16 between the substrate transfer chamber 22 and the circulation channel 24 using the fan filter unit 11. be.

The circulation channel 24 may be provided with a filter different from the filter 14 provided in the substrate transfer chamber 22 . It may be provided separately from the fan 12 provided on the ceiling 20b.

The gas introduction part 16 is provided in the circulation channel 24 near the ceiling 20b of the housing 20. As shown in FIG. The gas introduction part 16 has a gas discharge nozzle for discharging an inert gas such as nitrogen, and introduces the gas into the housing 20 . Gas is supplied to the gas introduction part 16 from a gas tank (not shown). The gas introduction part 16 shown in FIG. 1 discharges gas toward the fan 12 in the circulation flow path 24, but the gas introduction part 16 of the EFEM 10 is not limited to this. The substrate transfer chamber 22 may be provided with a gas discharge nozzle arranged directly below the substrate transfer chamber 22 .

The gas introduction unit 16 is controlled by the control unit 50 and introduces gas into the EFEM 10 . For example, when it is desired to improve the cleanliness of the substrate transfer chamber 22, the control unit 50 controls the gas introduction unit 16 to start introducing gas into the housing 20, or to introduce gas into the housing 20. It is possible to increase the amount of gas introduced per unit time. At this time, in order to prevent outside air from flowing into the substrate transfer chamber 22 and lowering the cleanliness of the substrate transfer chamber 22, the inside of the housing 20 filled with gas is preferably kept at a positive pressure. .

The circulation flow path 24 is provided with a first measurement section 28 that measures at least one of the flow rate and pressure of the gas circulating in the housing 20 . Examples of the flowmeter used as the first measurement unit 28 include a thermal flowmeter, an impeller flowmeter, a Karman vortex flowmeter, etc. A pressure gauge used as the first measurement unit 28 includes a diaphragm pressure gauge. , gauge pressure gauges, differential pressure gauges, absolute pressure gauges, etc., but are not particularly limited. Also, the first measuring unit 28 may have both a flow meter and a pressure gauge, and may be able to measure both the gas flow rate and the gas pressure.

The first measurement unit 28 may be provided in the flow path on the inner side of the housing 20 from the adjustment unit 30 connected to the discharge opening 20aa formed in the circulation flow path 24. It may be provided in the transfer chamber 22 . A measurement result of the first measurement unit 28 is sent to the control unit 50 .

The adjustment unit 30 is attached to a portion of the side wall 20a that forms part of the wall of the circulation channel 24 and is close to the floor. The side wall 20a is formed with a discharge opening 20aa for discharging a part of the gas circulating in the housing 20, and one end of the adjusting section 30 is connected to the discharge opening 20aa. The adjustment unit 30 is composed of, for example, an electromagnetic valve. The adjustment unit 30 is driven by a control signal from the control unit 50, and changes the amount of opening of the electromagnetic valve provided between the circulation flow path 24 and the connection pipe 40 to adjust the discharge of gas from the housing 20. .

The other end of the adjustment section 30 is connected to a connection pipe 40 that connects to a discharge pipe 60 in a semiconductor factory. The gas inside the housing 20 passes through the discharge opening 20 aa and the adjustment section 30 , and further passes through the connection pipe 40 and is discharged to the discharge pipe 60 .

FIG. 2 is a conceptual diagram showing the discharge pipe 60. As shown in FIG. The discharge pipe 60 connects the connection pipe 40 and the like to a plurality of adjustment units such as the adjustment units 30 of the plurality of EFEMs 10 provided in the factory and the adjustment units of other devices (for example, processing equipment) other than the EFEM 10. connected through The discharge pipe 60 is connected to an exhaust means such as a pump, and the inside of the discharge pipe 60 is preferably maintained at a negative pressure.

As shown in FIG. 1 , the connection pipe 40 is provided with a second measurement section 42 that measures at least one of the flow rate and pressure of the gas discharged through the adjustment section 30 . The flowmeter and pressure gauge used as the second measurement unit 42 may be the same as those used for the first measurement unit 28, but are not particularly limited. Moreover, the second measuring unit 42 may have both a flow meter and a pressure gauge, and may be able to measure both the gas flow rate and the gas pressure.

The second measurement unit 42 may measure the same physical quantity (flow rate or pressure) as the first measurement unit 28 or may measure a different physical quantity from the first measurement unit 28 . However, the second measurement unit 42 is preferably a flowmeter that measures the flow rate. As a result, the amount of gas discharged from the housing 20 can be directly measured, and the measurement result of the amount of discharge can be used for adjusting the amount of gas discharged by the adjustment unit 30 through the control unit 50. The EFEM 10 can accurately manage gas consumption.

The second measurement unit 42 may be provided in the flow path closer to the discharge pipe 60 than the adjustment unit 30 connected to the discharge opening 20aa formed in the circulation flow path 24, and is provided in the discharge pipe 60. good too. However, when the second measuring unit 42 is a flow meter, the amount of gas discharged from the target EFEM 10 can be measured separately from the other EFEMs without being affected by the flow rate from other EFEMs. , is preferably located near the adjustment unit 30 .

The measurement result of the second measurement section 42 is sent to the control section 50 in the same manner as the measurement result of the first measurement section 28 .

The control unit 50 controls introduction of gas into the housing 20 by the gas introduction unit 16 and discharge of gas from the housing 20 by the adjustment unit 30 . The measurement results of the first measurement unit 28 and the second measurement unit 42 are input to the control unit 50, the control unit 50 performs a predetermined calculation using the measurement results, and gas introduction is performed based on the calculation results. It controls the unit 16 and the adjustment unit 30 . Accordingly, the adjustment unit 30 can perform gas discharge adjustment using the measurement results of the first measurement unit 28 and the second measurement unit 42, and the gas introduction unit 16 can perform gas discharge adjustment using the measurement results of the first measurement unit 28 and the second measurement unit 42. 28 or the measurement result of the second measurement unit 42 can be used to adjust the gas introduction. The control unit 50 is composed of, for example, a microprocessor or the like.

Although the control by the control unit 50 is not particularly limited, for example, the EFEM 10 uses the measurement results of the first measurement unit 28 and the second measurement unit 42 to determine the flow rate (circulation speed) of the gas in the housing 20. Alternatively, the adjustment unit 30 and the gas introduction unit 16 can be controlled so that both the pressure of the gas and the flow rate of the gas discharged from the housing 20 have desired values.

The adjustment unit 30 can adjust gas discharge using at least one of the measurement results of the first measurement unit 28 and the second measurement unit 42 . For example, the adjustment unit 30 can control the opening and closing of a valve of the adjustment unit 30 to adjust the discharge amount using the measurement result of only one of the first and second measurement units 28 and 42 . In this case, the control unit 50 may control by feeding back changes in the measured values of the first or second measuring units 28 and 42 that accompany changes in the opening amount of the valves.

Further, for example, the adjustment unit 30 can use the measurement results of the first and second measurement units 28 and 42 to control the opening and closing of the valves of the adjustment unit 30 to adjust the discharge amount. The EFEM 10 having such an adjustment unit 30 can adjust the discharge speed and discharge amount of the gas discharged from the housing 20 more accurately and quickly. This is because the discharge flow rate from the adjustment unit 30 is affected by both the state (pressure or flow rate) on the housing 20 side and the state on the discharge pipe 60 side.

Also, the negative pressure of the discharge pipe 60 shown in FIG. can prevent the problem that the discharge state of the gas from the adjustment unit 30 is affected by the fluctuation of the negative pressure of the discharge pipe 60 .

In this way, the EFEM 10, which is a circulating EFEM, detects the state inside the housing 20 and on the side of the discharge pipe 60 by means of the first measurement unit 28 and the second measurement unit 42. Even if the flow rate and pressure on the side fluctuate, the discharge speed and discharge amount of the gas discharged from the housing 20 can be appropriately adjusted.

Although the EFEM according to the present invention has been described by showing the embodiments, the technical scope of the present invention is not limited to the above-described embodiments, and it goes without saying that other embodiments and modifications are included. For example, in EFEM 10 shown in FIG. not limited to In the EFEM according to another embodiment, the adjustment unit 30 may be provided at a connection position between the substrate transfer chamber 22 and the connection pipe 40, and from the substrate transfer chamber 22 to the connection pipe 40 via the adjustment unit 30, A configuration in which the gas in the housing 20 is discharged may be employed.

Further, for example, in the EFEM 10 according to the embodiment, the adjustment unit 30 has an electromagnetic valve, but the adjustment unit 30 is not limited to this, and the adjustment unit 130 as shown in FIG. It can be used instead of the part 30 . As shown in FIG. 3 , the adjustment section 130 according to the modification has a movable plate 136 that functions as a mechanical valve body and a weight 138 attached to the movable plate 136 .

A movable plate 136 is housed within the box 132 . The movable plate 136 can rotate around a shaft 137 to open and close the discharge opening 20aa leading to the circulation channel 24 . A connection pipe 40 is connected to a box opening 134 formed in the box 132 .

The movable plate 136 receives the pressure of the circulation flow path 24 on one side and the pressure of the connecting pipe 40 on the other side, so that the inner side of the housing 20 (that is, the circulation flow path 24 ) with the adjusting section 130 interposed therebetween. and the discharge pipe 60 side (that is, the connection pipe 40), and the opening amount is determined.

Further, the weight 138 attached to the movable plate 136 is driven by a motor or the like controlled by the control unit 50 so that its center of gravity position changes in a direction toward or away from the shaft 137. can move. As a result, the weight 138 changes the coefficient that defines the relationship between the differential pressure between the inner side of the housing 20 and the side of the discharge pipe 60 and the amount of opening of the movable plate 136 (the amount of opening of the discharge opening 20aa by the movable plate 136). Acts as a modifier. A spring or the like that can change the biasing force to the movable plate 136 can also be used as the coefficient changing unit.

The control unit 50 shown in FIG. 1 controls the position of the weight 138 using at least one of the measurement results of the first measurement unit 28 and the second measurement unit 42, thereby causing the adjustment unit 130 to discharge gas. can make adjustments. As described above, the adjustment mechanism by the adjustment unit 30 is not limited to an electrically controlled valve such as an electromagnetic valve, and may be a mechanical valve or diaphragm having an electrically controllable coefficient changing unit attached thereto. There may be. An EFEM having such an adjustment section 130 also has the same effects as the EFEM 10 shown in FIG.

Further, although the EFEM 10 shown in FIG. 1 is configured such that the control unit 50 controls the adjustment unit 30, the adjustment unit 30 is not limited to this. For example, the adjustment unit 30 may be an electromagnetic valve that operates independently of the control unit 50, and the measurement results of the first measurement unit 28 and the second measurement unit 42 are directly transmitted to the adjustment unit 30. It may be in an input mode.

10 EFEM
DESCRIPTION OF SYMBOLS 11... Fan filter unit 12... Fan 14... Filter 16... Gas introduction part 20... Housing 20a... Side wall 20aa... Discharge opening 20b... Ceiling 20d... Intermediate wall 22... Substrate transfer chamber 24... Circulation channel 26... Substrate transfer robot 26a Arm 28 First measurement unit 30, 130 Adjustment unit 40 Connection pipe 42 Second measurement unit 50 Control unit 60 Discharge pipe 70 Load port device 72 Mounting table 80 FOUP
82... Substrate 132... Box 134... Box opening 136... Movable plate 137... Shaft 138... Weight

Claims (4)

a gas introduction part for introducing gas;
a housing in which a substrate transfer chamber and a circulation flow path are formed and in which the introduced gas circulates;
a connecting pipe that connects to a discharge pipe through which gas is discharged from a plurality of other devices;
One side is connected to a discharge opening formed in the circulation flow path, and the other side is connected to the connection pipe so that the gas is discharged from the housing through the connection pipe to the discharge pipe. an adjustment unit that adjusts the
a first measurement unit provided in a flow path on the inner side of the housing from the adjustment unit and measuring at least one of flow rate and pressure of the gas;
a second measuring unit provided in a flow path in the connecting pipe on the side of the discharge pipe from the adjusting unit and measuring at least one of flow rate and pressure of the gas;
The second measuring unit is arranged near the adjusting unit of the connecting pipe,
The adjustment unit uses the measurement result of the second measurement unit or the measurement results of the first measurement unit and the second measurement unit to determine the discharge according to the operation status of the plurality of other devices. An EFEM that regulates the discharge of the gas to the discharge line to eliminate the effect on the line . 2. The EFEM according to claim 1, wherein the adjustment unit adjusts the discharge of the gas using measurement results of the first measurement unit and the second measurement unit. 3. The EFEM according to claim 1, wherein said second measurement unit measures flow rate. The adjustment unit includes a valve element whose opening amount is determined based on the differential pressure between the inner side of the housing and the side of the discharge pipe with the adjustment unit interposed therebetween, and the first measurement unit and the second measurement unit. 4. The EFEM according to any one of claims 1 to 3, further comprising a coefficient changing unit that changes a coefficient that defines the relationship between the differential pressure and the opening amount using at least one of the measurement results.

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