A novel flow guiding structure and a high-cleanliness wafer photomask storage repository

Abstract

A novel diversion structure and a high-cleanliness wafer photomask storage repository according to the present invention include a transition plate structure provided on one side of the storage repository. The storage repository has a storage cavity. The transition plate structure includes a first plate body, a second plate body, and a third plate body. The first plate body and the third plate body are parallel to each other. The second plate body is connected between the first plate body and the third plate body. The second plate body is inclined downward toward the inner side of the storage cavity. A relief area for docking external devices is formed below the second plate body. The upper surface of the second plate body is used to divert the gas entering the storage cavity. The angle between the first plate body and the second plate body is 45°, and the angle between the second plate body and the third plate body is 45°. It can greatly increase the storage capacity of wafers while ensuring the cleanliness requirements.

Description

Technical Field

[0001] The invention relates to the technical field of wafer storage, and in particular to a novel flow guiding structure and a high-cleanliness wafer mask storage library. Background Art

[0002] In the semiconductor industry, wafers are an important part of it. Wafers refer to silicon wafers used to make silicon semiconductor circuits. High-purity polysilicon is dissolved and mixed with silicon crystal seeds, and then slowly pulled out to form cylindrical single crystal silicon. After grinding, polishing, and slicing, silicon crystal rods are formed into silicon wafers, that is, wafers.

[0003] Since wafers are easily contaminated during storage, the cleanliness of the wafer storage library needs to be controlled. In order to control the cleanliness in the prior art, the area of ​​the wafer storage library is generally limited, resulting in low space utilization and unable to meet the storage needs of large quantities of wafers. In addition, in order to meet the configuration requirements of the interface, a stepped structure is often required, which further reduces the cleanliness of the storage library. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a novel guide structure and a high-cleanliness wafer mask storage library, which can significantly increase the storage capacity of wafers while ensuring the cleanliness requirement.

[0005] The present invention relates to a novel flow guiding structure, comprising a transition plate structure arranged on one side of a storage chamber, the storage chamber having a storage chamber, the transition plate structure comprising a first plate body, a second plate body and a third plate body, the first plate body and the third plate body being parallel to each other, the second plate body being connected between the first plate body and the third plate body, the second plate body being inclined downwardly toward the inner side of the storage chamber, a avoidance zone for docking an external device being formed below the second plate body, the upper surface of the second plate body being used for guiding the gas entering the storage chamber, the angle between the first plate body and the second plate body being 45°, and the angle between the second plate body and the third plate body being 45°;

[0006] It also includes a first guide plate and a second guide plate, wherein the first guide plate is connected to or in contact with the lower side of the first plate body, and the second guide plate is connected to or in contact with the lower side of the third plate body, and the first guide plate and the second guide plate are inclined downward toward the inner side of the storage cavity, and the first guide plate and the second guide plate are provided in multiple numbers.

[0007] Further, it further includes a plurality of unidirectional air outlet structures connected to the bottom of the repository. The fans in the unidirectional air outlet structures and the fans in the fan filter unit are both connected to the control module. The control module is used to adjust the air volume of the fans in the unidirectional air outlet structures and the fan filter unit. The air inlet of the unidirectional air outlet structure is communicated with the storage cavity.

[0008] The present invention also provides a novel diversion structure and a high-cleanliness wafer photomask repository, including the above novel diversion structure, and further including a fan filter unit connected to the upper end of the repository. The air outlet of the fan filter unit is communicated with the storage cavity in the repository. A rack for storing wafers is arranged in the storage cavity, and the lowest storage position of the rack is more than 600 mm away from the ground.

[0009] Further, the air inlet speed of the fan filter unit is 0.35 - 0.55 m / s, and the air outlet volume of the storage cavity is 70% - 90% of the air inlet volume.

[0010] Further, the fan filter unit includes a support frame that moves laterally and a filter assembly connected within the support frame. The air inlet of the filter assembly is arranged on the side, the air outlet of the filter assembly is located at the bottom, and the upper end of the filter assembly contacts the floor slab or forms a gap.

[0011] Further, the bottom of the repository is connected with columns and support feet. The upper end of the column is connected to the repository, the support foot is connected to the bottom of the column, and the lower surface of the support foot contacts the ground.

[0012] Further, the number of the racks is 2. The two racks are symmetrically arranged along the central axis of the repository. A stacking channel is formed between the two racks, and a stacker that moves along the stacking channel is arranged in the stacking channel. The stacker is used to transfer wafers onto the racks or transfer wafers out of the racks.

[0013] Further, the repository is formed by splicing a plurality of plate bodies, and the splicing joints of the plate bodies are sealed with sealant.

[0014] Further, the filtration grade of the fan filter unit is U16 or above U16.

[0015] Further, a plurality of docking interfaces are arranged in the avoidance area. The docking interfaces are used for loading, unloading, connecting sensors, wafer detection equipment or wafer cleaning devices.

[0016] The advantages of the present invention are as follows: Due to the need for interface installation, the repository needs to be set with a wider upper part and a narrower lower part. Compared with the conventional rectangular splicing structure, by setting the transition plate structure in this design, it is not only convenient for the installation of external devices but also can effectively guide the airflow. At the same time, the second plate body is set as an inclined structure, which can also reduce the generation probability of turbulence and improve the stability of the air in the storage cavity. By setting the angle between the first plate body and the second plate body to 45° and the angle between the second plate body and the third plate body to 45°, the stability of gas flow can be significantly improved, the interference caused by gas flow to the rack can be effectively reduced, and the stability of the internal environment can be improved.

[0017] The lowest storage position of the rack is more than 600 mm away from the ground, preferably above 800 mm. Since turbulence is likely to occur at positions below 600 mm, causing the suspended particles in the gas to float, which affects the normal storage of wafers. In actual settings, the lowest storage position of the rack needs to be set to not less than 600 mm to reduce the probability of wafer damage.

[0018] To make the above and other objects, features, and advantages of the present invention more obvious and understandable, the following specifically presents preferred embodiments and, in conjunction with the accompanying drawings, provides a detailed description as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 is the overall structure schematic diagram of the new diversion structure and the high-cleanliness wafer photomask repository.

[0021] Figure 2 is the side structure schematic diagram of the repository.

[0022] Figure 3 is the internal structure schematic diagram of the repository.

[0023] Figure 4 is the structure schematic diagram of the bottom of the repository.

[0024] Figure 5 Simplified model diagram of the stacker and the shelf.

[0025] Figure 6 is the overall grid schematic diagram.

[0026] Figure 7 is the overall schematic diagram of the X-Y plane slices (Slice I - Slice IV).

[0027] Figure 8 The velocity field distribution diagram of Slice I (left) and Slice II (right), in m / s.

[0028] Figure 9 The velocity field distribution diagram of Slice III (left) and Slice IV (right), in m / s.

[0029] Figure 10 This is the overall schematic diagram of the XY plane slice (Slice V-Slice VII).

[0030] Figure 11 The velocity field distribution diagram of Slice V (left) and Slice VI (right), in m / s.

[0031] Figure 12 Slice VI velocity contour plot (left) and streamline plot (right).

[0032] Figure 13 The trace distribution diagrams are near the front panel air inlet (left), the rear panel air inlet (middle), and the top panel air inlet (right). DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] A novel air guide structure and a high-cleanliness wafer mask storage library in a preferred embodiment of the present invention include a storage library 1, wherein a fan filter unit is connected to the upper end of the storage library 1, and an air outlet of the fan filter unit is connected to a storage chamber 2 in the storage library, and a material rack 3 for storing wafers is arranged in the storage chamber 2, and the lowest storage position of the material rack 3 is greater than 600 mm from the ground;

[0035] One side of the storage chamber 1 has a transition plate structure 4, and the transition plate structure 4 includes a first plate body 41, a second plate body 42 and a third plate body 43. The first plate body 41 and the third plate body 43 are parallel to each other, and the second plate body 42 is connected between the first plate body 41 and the third plate body 43. The second plate body 42 is inclined toward the inner and lower side of the storage chamber, and an avoidance area 9 for docking external equipment is formed below the second plate body 42. The upper surface of the second plate body 42 is used to guide the gas entering the storage chamber 2.

[0036] In the above embodiments, the air inlet velocity of the fan filter unit is 0.35 - 0.55 m / s, and the air outlet volume of the storage cavity 2 is 70% - 90% of the air inlet volume. By controlling the air velocity and air outlet volume, the probability of turbulent flow generated by the air flow in the storage cavity 2 can be further reduced, and the stability of the gas pressure in the storage cavity 2 can be ensured. In the actual implementation process, the air outlet volume is controlled to be 80% of the air inlet volume. The storage cavity 2 is connected with a pressure relief valve and a pressure detection mechanism to prevent overpressure in the storage cavity 2.

[0037] Referring to Figure 2 and Figure 3 In the above embodiments, the storage repository 1 further includes a first guide plate 11 and a second guide plate 12. The first guide plate 11 is connected to the lower side of the first plate body 41, and the second guide plate 12 is in contact with the lower side of the third plate body 43. The first guide plate 11 and the second guide plate 12 are inclined downward to the inner side of the storage cavity 2. The number of the first guide plate 11 and the second guide plate 12 is set to be multiple. In the actual implementation process, the second guide plate 12 is located on the right side of the first guide plate 11.

[0038] Through the arrangement of the first guide plate 11 and the second guide plate 12, the air flow filtered by the fan filter unit can be quickly introduced to the bottom of the storage repository 1, reducing the generation of local turbulent flow or chaotic flow, further improving the cleanliness of the storage cavity 2, and being able to accelerate the gas replacement speed and shorten the purification time of the storage cavity 2. Specifically, one path of the air flow directly passes through the first guide plate 11 to reach the bottom of the storage cavity, and one path of the air flow is first deflected by the second plate body 42 and then secondarily deflected by the second guide plate 12 to reach the bottom of the storage cavity 2.

[0039] In the above embodiments, the bottom of the storage repository 1 is connected with a plurality of one-way air outlet structures 6. The fans in the one-way air outlet structures 6 and the fans in the fan filter unit are both connected to the control module, and the control module is used to adjust the air volume of the fans in the one-way air outlet structures and the fan filter unit. In the actual implementation process, the filtration grade of the fan filter unit is U16 or above U16.

[0040] In the above embodiments, the fan filter unit includes a support frame that moves laterally and a filter assembly connected within the support frame. The air inlet of the filter assembly is arranged on the side, the air outlet of the filter assembly is located at the bottom, and the upper end of the filter assembly is in contact with the floor slab or forms a gap. It can make full use of the space and improve the load-bearing capacity of the storage repository 1.

[0041] Referring to Figure 2 , Figure 3 and Figure 4, in the above embodiment, the bottom of the repository 1 has a bottom plate 10, the bottom plate 10 is connected with columns 7 and support feet 8, the upper end of the column 7 is connected with the repository 1, the support feet 8 are connected to the bottom of the column 7, and the lower surface of the support feet 8 contacts the ground.

[0042] In the above embodiment, the number of the racks 3 is two, the two racks 3 are symmetrically arranged along the central axis of the repository, a stacking channel is formed between the two racks 3, and a stacker moving along the stacking channel is arranged in the stacking channel. The stacker is used to transfer wafers to the racks or transfer wafers out of the racks 3.

[0043] In the above embodiment, the repository 1 is formed by splicing a plurality of plate bodies, and the splicing joints of the plate bodies are sealed with sealant.

[0044] In the above embodiment, a plurality of docking interfaces are arranged in the avoidance area 9, and the docking interfaces are used to connect loading equipment, unloading equipment, sensors, wafer detection equipment or wafer cleaning devices.

[0045] Before loading the rack 3 of the repository 1, first turn on the fan filter unit and the unidirectional air outlet structure to replace the air in the storage cavity 2 until the air in the storage cavity 2 meets the class 10 or above standard. By setting the transition plate structure 4, it is convenient to install external devices and can effectively guide the air flow. At the same time, the second plate body 42 is set as an inclined structure, which can also reduce the generation probability of turbulence and improve the stability of the air in the storage cavity 2; the lowest storage position of the rack 3 is more than 600 mm from the ground, preferably above 800 mm. Since turbulence is likely to occur at positions below 600 mm, causing the suspended particles in the gas to float upward and affecting the normal storage of wafers, in actual setting, the lowest storage position of the rack 3 needs to be set not lower than 600 mm to reduce the damage probability of wafers.

[0046] In one of the embodiments, the angle between the first plate body and the second plate body is 45°, and the angle between the second plate body and the third plate body is 45°. In order to verify the implementation effect of this solution, a simulation experiment was carried out on this implementation scheme, and the reported content is as follows.

[0047] 1. Overview

[0048] This report uses CFD numerical analysis software to perform numerical simulation and analysis on the stacker and the shelves in a given workshop, and calculates the air velocity field distribution in the workshop.

[0049] 2. Model Simplification and Mesh Generation

[0050] Before simulating the fluid in the storage workshop, model simplification is carried out first. The model simplification process is performed using ANSYS SpaceClaim. Small feature structures in the original model that have little impact on the numerical results are removed, and the fluid environment is simplified and geometrically cleaned as necessary to improve the mesh quality, reduce the number of meshes, and improve the calculation efficiency. The simplified model is as shown in Figure 4 shown below.

[0051] After model simplification, ANSYS FLUENT MESHING is used for computational mesh generation. A hybrid hexahedral mesh is used in this example, and mesh encryption is performed at the boundary layer to improve the resolution of the numerical solution for the flow field boundary layer. The total number of meshes is approximately 7 million (6999499), and the quality is detected by orthogonal quality. The overall mesh schematic diagram is as shown in Figure 5 shown below.

[0052] 3. Numerical Simulation

[0053] 3.1 Solution Model and Boundary Condition Setting

[0054] In this example, ANSYS Fluent is used for three-dimensional numerical solution, and the following simplified assumptions are made:

[0055] (1) The physical property parameters of the solid region and the fluid region are constants, and the fluid is air;

[0056] (2) The fluid is in a steady-state flow;

[0057] (3) The effects of gravity and temperature changes are not considered;

[0058] (4) The SST k- turbulence model is used for the viscosity and boundary layer effects of the fluid.

[0059] The air inlets of the air ducts are the FFUs at the top and sides of the workshop. The boundary condition is a uniform air flow perpendicular to the boundary, where the velocity magnitude at the top is 0.55 m / s and the velocity magnitude at the sides is 0.3 m / s. The ventilation holes at the bottom of the workshop are the air duct outlets, and the boundary condition is set as a pressure outlet.

[0060] 3.2 Simulation Results

[0061] 3.2.1 Velocity Distribution in the X-Y Plane

[0062] After obtaining the numerical steady-state solution using ANSYS Fluent simulation, first as shown in Figure 6The following representative X-Y planes are intercepted and denoted as Slice I to Slice IV respectively. Among them, Slice I shows the air flow in the open area inside the workshop, Slice II passes through the center of the shelves; Slice III and Slice IV pass through the two main bodies of the stacker respectively. The velocity distribution diagrams and streamline diagrams of this series of planes can be viewed in Figure 7 and Figure 8 respectively.

[0063] 3.2.2 Velocity Distribution of Y-Z Plane

[0064] The air flow field distribution in another direction is as follows. Figure 9 The following representative Y-Z planes are intercepted and denoted as Slice V to Slice VIII respectively. Among them, Slice V passes through the sides of multiple shelves and the center of the bottom plate outlet; Slice VI passes through the sides of the shelves; Slice VII shows the plane when the fluid passes through the central axis, that is, the moving area of the stacker; Slice VIII shows the flow situation at the center of the shelves above the operation platform. The velocity distribution diagrams and streamline diagrams of this series of planes can be viewed in Figure 10 and Figure 11 respectively.

[0065] 3.2.3 Trace Distribution

[0066] The trace is the curve formed by the path of fluid particles at different times. The air flow trajectory can be obtained from the trace distribution of fluid particles near the air inlet. The trace distribution diagrams near different air inlets obtained through numerical simulation are as shown in Figure 12 . It can be seen that the traces of the top air inlet basically reach the bottom air outlet from top to bottom through the area in the middle of the container, and do not flow through the shelf area too much. After the fluid entering the workshop from the front and rear air inlets flows through the containers on this side, it flows downward with the fluid from the top air inlet in the middle area and does not have a great impact on the containers on the opposite side.

[0067] 4. Conclusion Analysis and Suggestions

[0068] From the preliminary analysis of the above numerical simulation, the current design of the stacker and shelves is relatively reasonable and the air flow is stable.

[0069] In the present invention, specific embodiments are used to elaborate the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the scope of the specific implementation manner. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A novel flow guiding structure, characterized in that: It includes a transition plate structure arranged on one side of the repository. The repository has a storage cavity. The transition plate structure includes a first plate body, a second plate body and a third plate body. The first plate body and the third plate body are parallel to each other. The second plate body is connected between the first plate body and the third plate body. The second plate body inclines downward to the inner side of the storage cavity. A relief area for docking external devices is formed below the second plate body and is arranged as a stepped structure. The upper surface of the second plate body is used for guiding the gas entering the storage cavity. The angle between the first plate body and the second plate body is 45°. The angle between the second plate body and the third plate body is 45°; It further includes a first flow guide plate and a second flow guide plate. The first flow guide plate is connected or in contact with the lower side of the first plate body. The second flow guide plate is connected or in contact with the lower side of the third plate body. The first flow guide plate and the second flow guide plate incline downward to the inner side of the storage cavity. The number of both the first flow guide plate and the second flow guide plate is set to be multiple.

2. The novel flow guiding structure according to claim 1, characterized in that: It further includes a plurality of one-way air outlet structures connected to the bottom of the repository. The fans in the one-way air outlet structures and the fans in the fan filter unit connected to the upper end of the repository are both connected to the control module. The control module is used to adjust the air volume of the fans in the one-way air outlet structures and the fan filter unit. The air inlet of the one-way air outlet structure is communicated with the storage cavity.

3. A novel flow guiding structure and a high-purity wafer photomask storage library, including the novel flow guiding structure according to claim 1 or 2, characterized in that; It further includes a fan filter unit connected to the upper end of the repository. The air outlet of the fan filter unit is communicated with the storage cavity in the repository. A rack for storing wafers is arranged in the storage cavity. The lowest storage position of the rack is more than 600 mm away from the ground.

4. The novel flow guiding structure and the high-purity wafer photomask storage library according to claim 3, characterized in that: The inlet air speed of the fan filter unit is 0.35 - 0.55 m / s. The air outlet volume of the storage cavity is 70% - 90% of the inlet air volume.

5. The novel flow guiding structure and the high-purity wafer photomask storage library according to claim 3, characterized in that: The fan filter unit includes a support frame that moves laterally and a filter assembly connected in the support frame. The air inlet of the filter assembly is arranged on the side. The air outlet of the filter assembly is located at the bottom. The upper end of the filter assembly is in contact with the floor slab or forms a gap.

6. The novel flow guiding structure and the high-purity wafer photomask storage library according to claim 3, characterized in that: The bottom of the repository is connected with columns and support feet. The upper ends of the columns are connected with the repository. The support feet are connected to the bottoms of the columns. The lower surfaces of the support feet are in contact with the ground.

7. The novel flow guiding structure and the high-purity wafer photomask storage library according to claim 3, characterized in that: The number of the racks is 2. The two racks are symmetrically arranged along the central axis of the repository. A stacking channel is formed between the two racks. A stacker that moves along the stacking channel is arranged in the stacking channel. The stacker is used to transfer wafers onto the racks or transfer wafers out of the racks.

8. The novel flow guiding structure and the high-purity wafer photomask storage library according to claim 3, characterized in that: The repository is formed by splicing a plurality of plate bodies. The splicing joints of the plate bodies are sealed with sealant.

9. The novel flow guiding structure and the high-purity wafer photomask storage library according to claim 3, characterized in that: The filtration grade of the fan filter unit is U16 or above U16.

10. The novel flow guiding structure and the high-purity wafer photomask storage library according to claim 3, characterized in that: A plurality of docking interfaces are arranged in the relief area. The docking interfaces are used for loading, unloading, connecting sensors, wafer detection devices or wafer cleaning devices.

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