KR20220059728A - Shelf unit and mask storing device having the same - Google Patents

Abstract

A shelf unit according to the present invention can include a shelf frame provided along the horizontal and vertical directions and partitioned into a plurality of areas, and shelf modules detachably provided to each area of the shelf frame and for stacking masks. Since the shelves of the present invention can be separated from the shelf frame, maintenance of the shelf unit is easy.

Description

Shelf unit and mask storing device having the same

The present invention relates to a shelf unit and a mask storage apparatus having the same, and more particularly, to a shelf unit for loading masks used in an exposure process and a mask storage apparatus having the same.

Masks used in an exposure process during a semiconductor device manufacturing process may be stored on shelves.

According to the prior art, the operation of transferring the container in which the masks are loaded to the shelves and the operation of transferring the masks to the shelves are performed by a worker's manual operation.

When the container is manually transported, vibration may be transmitted to the mask, and thus the mask may be damaged. In addition, when the mask is manually transferred to the shelves, the mask may be contaminated by foreign substances. Therefore, the quality of the mask may be deteriorated.

Since the mask is manually loaded onto the shelves, it takes a lot of time to transport and load the mask. Accordingly, productivity of the mask transfer and loading process may be reduced.

Further, according to the prior art, the shelves are provided in a cylindrical shape so that the masks are vertically loaded on the shelves.

A fan filter unit is provided above the shelves to form a downdraft. Foreign substances on the shelves positioned at the upper end of the shelves are easily removed by the downdraft. However, since the downdraft becomes weaker toward the lower shelves, it is difficult to remove foreign substances from the lower shelves.

In addition, since the shelves are formed in a cylindrical assembly, it is difficult to separate the shelves individually. Therefore, it is difficult to maintain the shelves.

The present invention provides a shelf unit in which foreign substances are easily removed and maintenance is convenient.

The present invention provides a mask storage device having the above shelf unit.

The shelf unit according to the present invention includes a shelf frame divided into a plurality of regions and detachably provided in each region of the shelf frame, which is provided in a horizontal direction and a vertical direction, and includes shelf modules for loading masks. can

According to embodiments of the present invention, each of the shelf modules may be formed by stacking a plurality of shelves vertically to enable individual separation.

According to embodiments of the present invention, the shelf unit is disposed on the rear surface of each shelf module, and forms an airflow in the horizontal direction toward the front surface of each shelf module to form an airflow that is loaded on the shelf modules It may further include first fan filter units for removing foreign substances adhering to the masks.

According to embodiments of the present invention, the shelf unit is connected to the first fan filter units, respectively, and provides ionized air to the first fan filter unit to remove static electricity from the mask and the foreign material. It may further include air supply units that do.

The mask storage apparatus according to the present invention includes a chamber, a port unit provided on the outside of the chamber, in which a container on which masks are loaded, and a port unit provided inside the chamber, the state of the mask and the input direction of the mask a vision unit for performing a vision inspection to confirm and a robot unit for transporting the masks from the , wherein the shelf unit is provided in a horizontal direction and an up-down direction, and is detachably provided in each area of a shelf frame divided into a plurality of areas and the shelf frame, It may include shelf modules for loading items.

According to embodiments of the present invention, the mask storage device is disposed on the rear surface of each shelf module, and forms an airflow in the horizontal direction toward the front surface of each shelf module to be loaded on the shelf modules. It may further include first fan filter units for removing foreign substances adhering to the masks.

According to one embodiment of the present invention, the mask storage device is provided on the upper surface of the chamber, and the foreign material removed by the first fan filter units by forming a downdraft inside the chamber is removed from the mask. It may further include a second fan filter unit to suppress the recontamination of the air.

The shelf unit according to the present invention is provided so that the shelves are detachably attached to the shelf frame. Since the shelves can be separated from the shelf frame, maintenance of the shelf unit is easy.

Since the first fan filter unit forms the horizontal airflow toward the front surface of each shelf, foreign substances adhering to the masks loaded on the shelves can be removed. In addition, since the second fan filter unit forms the downdraft, it is possible to suppress recontamination of the masks by the foreign material removed by the first fan filter unit.

Also, since the air supply unit provides the ionized air, static electricity from the mask and the foreign material may be removed. Therefore, it is possible to suppress adhering to the foreign material to the mask, and the foreign material adhering to the mask can be easily removed.

Since the mask storage apparatus according to the present invention can transfer the mask to the shelf unit using the robot unit, it is possible to reduce the time required for the transfer and loading of the mask. Accordingly, productivity of the process of transferring and loading the mask to the shelf unit may be improved.

Since the mask is transferred to the robot unit, it is possible to reduce the transmission of vibration to the mask, thereby reducing damage to the mask due to the vibration. In addition, since the mask is transferred to the robot unit, it is possible to reduce contamination of the mask by foreign substances. Therefore, the quality of the mask can be improved.

1 is a schematic side cross-sectional view for explaining a mask storage device according to an embodiment of the present invention.
FIG. 2 is a schematic plan cross-sectional view for explaining the mask storage device shown in FIG. 1 .
FIG. 3 is a schematic cross-sectional view for explaining the vision unit shown in FIG. 1 .
4 is a plan view for explaining a mask.
5 is a schematic side view for explaining the inversion unit shown in FIG.
6 is a schematic side view for explaining another example of the inversion unit shown in FIG.
FIG. 7 is a front view illustrating the shelf unit shown in FIG. 1 .
FIG. 8 is a side cross-sectional view illustrating the shelf unit, the first fan filter unit, and the second fan filter unit shown in FIG. 1 .

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numerals have been used for like elements. In the accompanying drawings, the dimensions of the structures are enlarged than the actual size for clarity of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Figure 1 is a schematic side cross-sectional view for explaining a mask storage device according to an embodiment of the present invention, Figure 2 is a schematic plan cross-sectional view for explaining the mask storage device shown in Figure 1, Figure 3 is Figure 1 It is a schematic cross-sectional view for explaining the vision unit shown in Fig. 4 is a plan view for explaining the mask, Fig. 5 is a schematic side view for explaining the inversion unit shown in Fig. 1, Fig. 6 is in Fig. It is a schematic side view for explaining another example of the shown inversion unit, FIG. 7 is a front view for explaining the shelf unit shown in FIG. 1, and FIG. 8 is the shelf unit shown in FIG. 1, the first fan filter unit and It is a side cross-sectional view for explaining a 2nd fan filter unit.

1 to 7 , the mask storage device 100 includes a chamber 110 , a port unit 120 , a vision unit 130 , an inversion unit 150 , a shelf unit 160 , and a first fan filter. It may include a unit 170 , an air supply unit 175 , a robot unit 180 , and a second fan filter unit 190 .

The chamber 110 provides a space for accommodating the mask 10 . The chamber 110 may have a substantially hexahedral shape.

The port unit 120 is provided outside the chamber 110 , and the container 20 on which the masks 10 are loaded may be seated.

The port unit 120 may include a load port 121 and a door opening/closing unit 123 .

The load port 121 supports the vessel 20 . The container 20 may be loaded into the load port 121 or unloaded from the load port 131 . At this time, the container 20 may be loaded and unloaded by a vehicle (not shown) of the overhead transport device, or may be manually loaded and unloaded by a worker.

The load port 121 may be divided into a vehicle load port and a manual load port. In this case, the vehicle load port and the manual load port may be located at different heights.

In addition, loading and unloading of the container 20 may be alternately performed in each of the load ports 121 . Alternatively, the load port 121 may be divided into a loading port for loading the container 20 and an unloading load port for unloading the container 20 .

The door opening and closing part 123 is provided inside the chamber 110 which is one side of each load port 121 , and opens and closes a door (not shown) of the container 20 seated in the load port 121 . do.

The port unit 120 may further include a mapping sensor (not shown). The mapping sensor may check the presence and location of the masks 10 in the container 20 with the door opened.

The vision unit 130 is provided inside the chamber 110 , and performs a vision inspection to confirm the state of the mask 10 and the input direction of the mask 10 .

The vision unit 130 may include a vision stage 131 , a camera 132 , a first illumination unit 133 , a second illumination unit 137 , and an image processing unit 142 .

The vision stage 131 supports the mask 10 to perform the vision inspection.

Since the robot unit 170 grips both sides of the mask 10 and transports it, if the size of the vision stage 131 is larger than the size of the mask 10 , the robot unit 170 moves the mask 10 . may collide with the vision stage 131 when loading and unloading.

The size of the vision stage 131 may be the same as or smaller than the size of the mask 10 so that the robot unit 170 loads and unloads the mask 10 without colliding with the vision stage 131 .

The vision stage 131 may be used as a buffer stage for temporarily storing the mask 10 .

The camera 132 is provided above the vision stage 131 and photographs the mask 10 supported by the vision stage 131 .

The first illumination unit 133 has brightfield illumination light irradiated coaxially with the central axis of the camera 132 .

Specifically, the first lighting unit 133 may include a first light source 134 , a half mirror 135 , and a condensing lens 136 .

The first light source 134 irradiates light in a horizontal direction.

The half mirror 135 reflects the light emitted from the first light source 134 in a direction coaxial with the central axis of the camera 132 to form the brightfield illumination light.

The condensing lens 136 concentrates the light reflected by the half mirror 135 .

The image processing unit 142 reads the state of the mask 10 using the image captured by the camera 142 . Since the first illumination unit 133 forms the brightfield illumination light, the image of the mask 10 photographed by the camera 132 is bright. Accordingly, it is easy for the image processing unit 142 to check the state of the mask 10 from the image of the mask 10 . That is, the image processing unit 142 can easily read foreign substances, cracks, and scratches of the mask 10 from the image of the mask 10 .

The second illumination unit 137 includes a dark field illumination light irradiated at a predetermined angle with the central axis of the camera 132 and a side illumination light irradiated perpendicular to the central axis of the camera 132 .

Specifically, the second lighting unit 137 may include a lighting structure 138 , second light sources 139 , third light sources 140 , and a lift driving unit 141 .

The lighting structure 138 has a ring shape surrounding a side surface of the vision stage 131 .

The second light sources 139 are provided along the inner circumference of the lighting structure 138 . The second light sources 139 may be positioned slightly higher than the mask 10 supported by the vision stage 131 . For example, the second light sources 139 may be positioned at the same height. Alternatively, the second light sources 139 may be located at different heights.

The second light sources 139 irradiate light at a predetermined angle with the central axis of the camera 132 to form the dark field illumination light.

The third light sources 140 are provided along the inner circumference of the lighting structure 138 . The third light sources 140 may be positioned at the same height as the mask 10 supported by the vision stage 131 .

The third light sources 140 irradiate light so as to be perpendicular to the central axis of the camera 132 to form the side illumination light.

The elevating driving unit 141 may elevate the lighting structure 138 in a vertical direction.

Specifically, in the lifting driving unit 141 , the lighting structure 138 surrounds the side surface of the vision stage 131 at a first position and the lighting structure 138 moves the side surface of the vision stage 131 . The lighting structure 138 may be lifted up and down between the exposed second positions.

The second position may be a position at which the lighting structure 138 is lowered from the first position. When the lighting structure 138 is positioned in the second position, the robot unit 170 loads and unloads the mask 10 into the vision stage 131 without interference of the lighting structure 138 . can

The lifting driving unit 141 may be configured using a motor and a power transmission device including a timing belt and pulleys, or may be configured as a linear motor, a ball screw, a cylinder, or the like.

The image processing unit 142 reads the input direction and whether the mask 10 is inverted using the image captured by the camera 142 .

The second illumination unit 137 forms the dark field illumination light and the side illumination light, and the dark field illumination light and the side illumination light are reflected by the mask 10 and provided to the camera 132 , so that the camera 132 ), the image of the mask 10 is dark, but visibility of the three-dimensional part is good. In particular, the dark field illumination light and the side illumination light may be reflected by the notches 11 provided in some of the upper surface corners of the mask 10 , and the reflected light may be scattered and provided to the camera 132 . .

For example, the notches 11 may be provided at three corners among four corners of the upper surface of the mask 10 . Alternatively, the notches 11 may be provided at one of four corners of the upper surface of the mask 10 .

Accordingly, the image processing unit 142 may read the notches 11 in the image of the mask 10 and easily check the input direction of the mask 10 using the positions of the notches 11 .

Also, the image processing unit 142 may check whether the mask 10 is inverted by using whether the notches 11 of the mask 10 are read from the image of the mask 10 . That is, when the notches 11 of the mask 10 are read in the image of the mask 10 , the mask 10 is in a normal state, and in the image of the mask 10 , the If the notches 11 are not read, the mask 10 is in an inverted state.

The image processing unit 142 may be provided inside the chamber 110 and may be directly connected to the camera 132 . In contrast, the image processing unit 142 may be provided outside the chamber 110 and may be connected to the camera 132 through wired or wireless communication.

Also, the image processing unit 142 may store the reading result for each mask 10 .

Meanwhile, the camera 132 may photograph the mask 10 while the brightfield illumination light of the first illumination unit 133 and the dark field illumination light and the side illumination light of the second illumination unit 137 are all irradiated. . Accordingly, the image processing unit 142 may simultaneously check the state of the mask 10 , the input direction of the mask 10 , and whether the mask 10 is inverted in the image of the mask 10 . Therefore, the time required to check the state of the mask 10 , the input direction of the mask 10 , and whether the mask 10 is inverted can be shortened.

The inversion unit 150 is provided inside the chamber 110 , and may invert the mask 10 so that the vision inspection is performed on both surfaces of the mask 10 .

The inversion unit 150 may include an inversion stage 151 , a gripper 153 , and a driving unit 155 .

The inversion stage 151 supports the mask 10 . For the same reason as the vision stage 131 , the size of the inversion stage 151 may be the same as or smaller than the size of the mask 10 .

Also, the inversion stage 151 may be used as a buffer stage for temporarily storing the mask 10 .

The gripper 153 is disposed on one side of the inversion stage 151 and grips both sides of the mask 10 .

The driving unit 155 includes a first driving unit that operates the gripper 153 so that the gripper 153 grips the mask 10 , and a second driving unit that rotates the gripper 153 to invert the mask 10 . It may include a second driving unit and a third driving unit for moving the gripper 153 in the horizontal and vertical directions. For example, the first to third driving units may be configured using a motor and a power transmission device including a timing belt and pulleys, respectively, or may be configured as a linear motor, a ball screw, a cylinder, or the like.

Meanwhile, as shown in FIG. 6 , the inversion unit 150a is provided on one side of the vision stage 131 , and is mounted on the vision stage 131 to perform the vision inspection on both sides of the mask 10 . The seated mask 10 is inverted.

The inversion unit 150a may include the gripper 153 and the driving unit 155 without the inversion stage 151 .

A detailed description of the gripper 153 and the driving unit 155 includes the gripper 153 of the inversion unit 150 and the It is substantially the same as the description of the driving unit 155 .

The shelf unit 160 is provided inside the chamber 110 and loads the masks 10 .

The shelf unit 160 includes a shelf frame 161 and shelf modules 163 .

The shelf frame 161 is provided along the left-right direction and the vertical direction among the horizontal directions, and may be divided into a plurality of areas.

For example, as shown, the shelf frames 161 may be arranged in two rows to face each other and parallel to each other. As another example, although not shown, the shelf frames 161 may be arranged in one row.

The shelf modules 163 are detachably provided in each area of the shelf frame 161 . For example, the shelf modules 163 may be inserted into and discharged from the rear of the shelf frame 161 into the respective areas.

Each of the shelf modules 163 may be formed by stacking a plurality of shelves 165 vertically. In this case, each shelf module 163 may separate the shelves 165 individually. Accordingly, maintenance of the shelf module 163 is convenient.

The masks 10 may be supported by the respective shelves 165 in a horizontal state. Support protrusions 167 for supporting the masks 10 may be provided on upper surfaces of the respective shelves 165 .

The first fan filter units 170 may be mounted on the rear surface of each shelf module 163 . In this case, the rear surface of each of the shelf modules 163 may be opposite to the front surface through which the masks 10 are input and discharged in the respective shelf modules 163 .

The first fan filter units 170 form an airflow in the horizontal direction toward the front surface of each shelf module 163 . Foreign substances on the shelves 165 and foreign substances attached to the masks 10 loaded on the shelves 165 may be removed by the horizontal airflow.

The air supply units 175 are respectively connected to the first fan filter units 170 , and provide ionized air to the first fan filter units 170 .

The ionized air may remove static electricity from the masks 10 loaded on the shelves 165 . Since the masks 10 maintain a state in which the static electricity is removed, it is possible to suppress the foreign substances from adhering to the masks 10 by the static electricity.

In addition, the ionized air may remove static electricity from the foreign material attached to the masks 10 . Since the static electricity of the foreign material is removed, the foreign material may be easily removed from the masks 10 by the horizontal airflow.

Since the first fan filter units 170 and the air supply units 175 are mounted on the shelf module 163 , when the shelf modules 163 are attached to and detached from the shelf frame 161 , the first fan The filter units 170 and the air supply units 175 are also detachable like the shelf modules 163 .

The second fan filter unit 190 is provided on the upper surface of the chamber 110 , and forms a downward airflow inside the chamber 110 . The foreign material removed by the first fan filter unit 170 may descend to the bottom of the chamber 110 by the descending airflow. In addition, since it is possible to suppress the foreign material from being provided to the other shelf modules 163 by the downdraft, it is possible to suppress the foreign material from recontaminate the masks 10 .

The robot unit 180 is provided inside the chamber 110 , and the mask ( 10) are transported.

The robot unit 180 may include a transfer robot 181 and a robot arm 183 .

The transfer robot 181 may be provided to enable the rotational movement and the vertical movement for the transfer of the masks 10 .

Although not shown in detail, the transfer robot 181 may include a fourth driving unit for moving the transfer robot 181 in the vertical direction and a fifth driving unit for rotating the transfer robot 181 . Alternatively, the fifth driving unit may rotate the robot arm 183 .

For example, the robot unit 180 is provided with a guide rail 185 provided in the vertical direction inside the chamber 110, and the transfer robot 181 is driven by the fourth driving unit. It may move in the vertical direction along the guide rail 185 .

A plurality of the transfer robots 181 may be provided to quickly transfer the masks 10 .

In addition, the robot arm 183 is for transferring the masks 10 , and the robot arm 183 includes the load port 120 , the vision unit 130 , the inversion unit 150 , and the shelf. It may be configured to be movable toward the unit 160 . The robot arm 183 may grip both sides of the mask 10 . As an example, the robot arm 183 may be a multi-joint robot arm that can be extended and contracted. The robot arm 183 may include a sixth driving unit for the robot arm 183 to grip and move the mask 10 .

The fourth to sixth driving units may be configured using a motor and a power transmission device including a timing belt and pulleys, respectively, or may be configured as a linear motor, a ball screw, a cylinder, or the like.

Since the transfer robot 181 is rotatable and the robot arm 183 can extend and contract, the robot arm 183 moves the mask ( 10) can be transported.

In addition, the transfer robot 181 may only move in the vertical direction but not in the horizontal direction. It is possible to reduce the generation of foreign substances according to the movement of the transfer robot 181 .

Since the transfer robot 181 can rotate and move in the vertical direction, and the robot arm 183 can extend and contract, the robot unit 180 is connected to the load port 120 and the vision. The masks 10 may be stably transferred between the unit 130 , the inversion unit 150 , and the shelf unit 160 .

As described above, since the mask storage device can load the mask onto the shelf unit with the robot unit, the time required for loading and unloading the mask can be reduced. Accordingly, productivity of the process of transferring and loading the mask to the shelf unit may be improved.

Since the mask is transferred to the robot unit, it is possible to reduce the transmission of vibration to the mask, thereby reducing damage to the mask due to the vibration. In addition, since the mask is transferred to the robot unit, it is possible to reduce contamination of the mask by foreign substances. Therefore, the quality of the mask can be improved.

The vision unit performs a vision inspection on the mask by simultaneously irradiating the brightfield illumination light, the darkfield illumination light, and the side illumination light. Foreign substances, cracks, and scratches on the mask can be accurately read under the influence of the brightfield illumination light. Accordingly, it is possible to accurately check the state of the mask.

Also, since the dark field illumination light and the side illumination light are scattered at the notch of the mask, it is possible to accurately read the notch of the mask. Accordingly, the input direction of the mask can be accurately confirmed.

If the input direction of the mask is confirmed, the masks may be loaded onto the shelf unit so that the masks have the same direction. Accordingly, it is possible to prevent reorientation of the masks.

The shelf unit is provided such that the shelves are detachably attached to the shelf frame. Since the shelves can be separated from the shelf frame, maintenance of the shelf unit is easy.

Since the first fan filter unit forms the horizontal airflow toward the front surface of each shelf, foreign substances adhering to the masks loaded on the shelves can be removed. In addition, since the second fan filter unit forms the downdraft, it is possible to suppress re-contamination of the masks by the foreign material removed by the first fan filter unit.

Also, since the air supply unit provides the ionized air, static electricity from the mask and the foreign material may be removed. Therefore, it is possible to suppress adhering to the foreign material to the mask, and the foreign material adhering to the mask can be easily removed.

Although the above has been described with reference to the preferred embodiment of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the following claims. You will understand that you can.

100: mask storage device 110: chamber
120: port unit 121: load port
123: door opening and closing unit 130: vision unit
131: vision stage 132: camera
133: first lighting unit 134: first light source
135: half mirror 136: condensing lens
137: second lighting unit 138: lighting structure
139: second light source 140: third light source
141: elevating driving unit 142: image processing unit
150, 150a: reversal unit 151: reversal stage
153: gripper 155: driving unit
160: shelf unit 161: shelf frame
163: shelf module 165: shelf
167: support protrusion 170: first fan filter unit
175: air supply unit 180: robot unit
181: transfer robot 183: robot arm
185: guide rail 190: second fan filter unit
10: mask 20: container

Claims (7)

a shelf frame provided along a horizontal direction and a vertical direction and divided into a plurality of areas; and
The shelf unit is provided detachably in each region of the shelf frame and includes shelf modules for loading masks. The shelf unit according to claim 1, wherein each of the shelf modules is formed by stacking a plurality of shelves vertically so that each shelf module can be separated. The method of claim 1, wherein each of the shelf modules is disposed on a rear surface of each shelf module, and an airflow is formed in the horizontal direction toward the front surface of each shelf module to remove foreign substances attached to the masks loaded on the shelf modules. Shelf unit further comprising first fan filter units. 4 . The method of claim 3 , further comprising air supply units respectively connected to the first fan filter units and configured to provide ionized air to the first fan filter unit to remove static electricity from the mask and the foreign substances. Shelf unit featuring. chamber;
a port unit provided on the outside of the chamber and on which a container on which masks are loaded;
a vision unit provided inside the chamber and configured to perform a vision inspection to check a state of the mask and an input direction of the mask;
a shelf unit provided in the chamber and configured to load the masks; and
a robot unit provided inside the chamber and transferring the masks between the port unit, the vision unit, and the shelf unit;
The shelf unit is
a shelf frame provided along a horizontal direction and a vertical direction and divided into a plurality of areas; and
The mask storage device is provided detachably in each region of the shelf frame and comprises shelf modules for loading masks. [Claim 6] The method of claim 5, wherein each of the shelf modules is disposed on a rear surface of each shelf module, and an airflow is formed in the horizontal direction toward the front surface of each shelf module to remove foreign substances attached to the masks loaded on the shelf modules. A mask storage device, characterized in that it further comprises first fan filter units. The second fan of claim 6 , wherein the second fan is provided on the upper surface of the chamber and forms a downdraft inside the chamber to prevent the foreign substances removed by the first fan filter units from recontaminate the masks. Mask storage device, characterized in that it further comprises a filter unit.

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