Packing unit and transport container

Abstract

A packing unit (10) for packing objects to be stored (80A) in a box-type container (200) so that the objects to be stored (80A) are divided into two rows at intervals in the width direction and divided into two layers in the vertical direction, the packing unit being provided with: a lower cushion (1) for supporting the two rows of objects to be stored (80A) in the lower layer; middle buffer pieces (3) which are respectively clamped between the upper layer and the lower layer of the object to be stored; an upper cushion (5) for holding the upper part of the object to be stored; and a vibration absorption unit (20) provided at the bottommost portion of the container, the vibration absorption unit (20) having a first flat plate (21), a second flat plate (22), and an elastic body (23) disposed between the first flat plate (21) and the second flat plate (22), the center of the elastic body (23) being located further outward than the center of gravity of the storage objects with respect to the middle of the two rows of storage objects. The distance (D) in the width direction between the center of the elastic body (23) and the center of gravity of the object to be stored is 2% or more of the maximum outer diameter of the elastic body (23) and 8% or less of the maximum outer diameter of the elastic body (23).

Description

Technical Field

[0001] The present invention relates to a packing unit for packing storage objects in a container and a transport container. Background Art

[0002] In recent years, the requirements for the quality of semiconductor wafers have become stricter, and damage to semiconductor wafers due to vibration and shock during transportation, adhesion of resin materials used in wafer fixing parts, and the like have become problems.

[0003] As a method of transporting semiconductor wafers, there is known a method of preparing a plurality of storage containers storing semiconductor wafers, packing the plurality of storage containers in a container, and transporting the containers by a transport device.

[0004] Therefore, in order to pack the storage container in the container, there is known a component (referred to as a packing unit) including a cushioning member interposed between the container and the storage container and a vibration absorbing unit provided below the cushioning member. It is known that the cushioning member is mainly formed of foamed polyurethane or the like, and the vibration absorbing unit is a structure including a pair of plastic plates and a plurality of elastic bodies sandwiched between the pair of plastic plates.

[0005] The vibration absorbing unit is a unit that suppresses vibration of the storage container during transportation by an elastic body. For example, Patent Document 1 describes a unit composed of a pair of corrugated boards made of synthetic resin and an elastic body sandwiched between the pair of corrugated boards made of synthetic resin.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2011-16549 Summary of the invention

[0009] Technical problem to be solved by the invention

[0010] The elastic body constituting the vibration absorbing unit has a function of absorbing vibrations and shocks by elastic deformation. However, depending on the position of the elastic body, the plastic plate may be greatly bent, and the storage container may be tilted or the buffer members may come into contact with each other.

[0011] Furthermore, regarding the number of elastic bodies, although the deflection of the plastic plate can be suppressed by arranging a plurality of them, on the other hand, the effect of absorbing vibrations and shocks is reduced, and therefore the number of elastic bodies needs to be arranged to the minimum necessary.

[0012] In particular, in the case of a structure in which storage containers are arranged in two layers in an upper and lower layer in a container, there is a problem that the storage containers arranged in the upper layer are tilted more significantly than the storage containers in the lower layer.

[0013] In addition, there is also a problem that the distance between the buffer member and the container becomes wider, and the buffering effect when a shock occurs during transportation is reduced.

[0014] An object of the present invention is to suppress inclination of a storage object and stably perform taking out of the storage object or a cushioning member in a packaging unit for packaging a storage object in a container and a transport container in which the packaging unit is accommodated.

[0015] Solutions for solving technical problems

[0016] The packing unit of the present invention is a packing unit for packing storage objects, which are containers for storing semiconductor wafers, in a box-type container in a manner that the storage objects are divided into two rows at intervals in the width direction and into two layers in the vertical direction, and is characterized by comprising: a lower buffer member that supports the lower parts of the two rows of storage objects in the lower layer; a middle buffer member that is sandwiched between the storage objects in the upper layer and the storage objects in the lower layer in each row of the storage objects; an upper buffer member that is arranged in each row of the two rows of storage objects in the upper layer to hold the upper parts of the storage objects; and a vibration absorbing unit that moves the lower buffer member from The container is supported downward and arranged at the bottom of the container, the vibration absorbing unit comprising: a first flat plate; a second flat plate, which is parallel to the first flat plate and arranged below the first flat plate; and an elastic body, which is arranged between the first flat plate and the second flat plate, and the number of the elastic body is the same as the storage objects in each layer, when viewed from above, the center of the elastic body is located outside the middle of two rows of storage objects than the center of gravity of the storage objects, and the distance between the center of the elastic body and the center of gravity of the storage objects in the width direction is greater than 2% of the maximum outer diameter of the elastic body and less than 8% of the maximum outer diameter of the elastic body.

[0017] In the packing unit, assuming that the interval between the centers of the elastic bodies adjacent in the row direction is Gx and the interval between the centers of the elastic bodies adjacent in the width direction is Gy, a ratio Gy / Gx of Gy to Gx may be 1 or more and 1.3 or less.

[0018] In the above-mentioned packing unit, the bending strength of the first flat plate may be 2 times or more and 3 times or less of the bending strength of the second flat plate.

[0019] In the above-mentioned packing unit, among the first flat plate and the second flat plate, at least the first flat plate has a cutout formed therein.

[0020] A transport container according to the present invention is characterized by comprising: the above-mentioned packing unit; and a box-type container for accommodating the packing unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a perspective view showing a packing state in which storage containers and cushioning materials are arranged in a container.

[0022] Figure 2 is along Figure 1 A cross-sectional view taken along line A1-A1.

[0023] Figure 3 is along Figure 1 A cross-sectional view taken along line A2-A2.

[0024] Figure 4 It is a three-dimensional diagram of a storage container.

[0025] Figure 5A It is a top view of the storage container.

[0026] Figure 5B It is a rear view of the container cover.

[0027] Figure 6 It is a cross-sectional view of a vibration absorbing unit according to an embodiment of the present invention.

[0028] Figure 7 yes Figure 6 The VII-VII arrow view is a top view of the vibration absorbing unit according to the embodiment of the present invention.

[0029] Figure 8 This is a cross-sectional view of the vibration absorbing unit according to the embodiment of the present invention, and is a view when eight elastic bodies are provided.

[0030] Fig. 9 This is a graph showing the displacement amount of the first flat plate when the position of the elastic body in the Y direction is changed.

[0031] Fig.10 This is a graph showing the displacement amount of the first flat plate when the positions of the elastic bodies in the Y direction are changed when there are eight elastic bodies.

[0032] Fig.11 It is a graph which shows the result of a vibration test.

[0033] Fig.12 It is a graph which shows the result of a vibration test.

[0034] Fig.13 It is a graph which shows the result of a vibration test.

[0035] Fig.14 This is a graph showing the correlation between the ratio Gy / Gx and RMS. DETAILED DESCRIPTION

[0036] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0037] The packing unit 10 of the present invention is a unit for packing a plurality of storage containers 80 in a container 200. A structure including the packing unit 10 and the box-type container 200 storing the packing unit 10 is referred to as a transport container 200A.

[0038] A plurality of semiconductor wafers W are stored in the storage container 80. Hereinafter, the storage container 80 storing the semiconductor wafers W is referred to as a storage object 80A.

[0039] The packing unit 10 includes a cushioning member group 100 including an upper cushioning member 5 , a middle cushioning member 3 , and a lower cushioning member 1 , and a vibration absorbing member 20 that supports the lower cushioning member 1 from below and is disposed at the bottom of the container 200 .

[0040] When the storage objects 80A are packed in the container 200 , the cushioning material group 100 is arranged between the plurality of storage objects 80A and the container 200 .

[0041] First, a container 200 in which a plurality of storage objects 80A are packed will be described. Figure 1 As shown, the container 200 is a box having a rectangular parallelepiped storage space and packing a plurality of (twelve in the present embodiment) storage objects 80A together with the cushioning material set 100 .

[0042] The container 200 includes a container body 201 with an open upper surface and a container cover 204 that closes the upper surface of the container body 201, and is box-shaped as a whole by the container body 201 and the container cover 204. The container body 201 is composed of four side plates 203 connected to each other to form a square tube shape and a bottom plate 202 that closes the bottom. The container 200 is formed of a material that can withstand transportation by a truck or the like, for example, a corrugated board, plastic, metal such as aluminum, or wood.

[0043] Next, the arrangement of the cushioning material group 100 and the storage object 80A will be described.

[0044] like Figures 1 to 3 As shown, the three storage objects 80A are arranged in two rows in the horizontal direction and in two layers in the vertical direction, and a total of 12 storage objects 80A are arranged in the container 200. That is, the packing unit 10 packs the storage objects 80A in the container 200 in a manner that the storage objects 80A are divided into two rows at intervals in the width direction and in two layers in the vertical direction.

[0045] The number of storage objects 80A in the row of the storage objects 80A is not limited thereto, and for example, the rows in which two storage objects 80A are arranged may be two rows and two layers may be arranged vertically.

[0046] In the following description, the direction in which the row of storage objects 80A extends is referred to as the X direction (row direction), the direction orthogonal to the X direction is referred to as the Y direction (width direction), and the up-down direction is referred to as the Z direction.

[0047] The cushioning member group 100 cushions and stores the two rows and two layers of the storage objects 80A. The cushioning member group 100 includes: a lower cushioning member 1 that supports the lower portion of the two rows of storage objects 80A in the lower layer; a middle cushioning member 3 that is sandwiched between the row of storage objects 80A in the upper layer and the row of storage objects 80A in the lower layer in each row of the storage objects 80A; and an upper cushioning member 5 that is arranged in each row of the two rows of storage objects 80A in the upper layer to hold the upper portion of the storage objects 80A.

[0048] In the following description, a state in which twelve storage objects 80A, two upper cushioning materials 5, two middle cushioning materials 3, and one lower cushioning material 1 are arranged in the container 200 is referred to as a packing state.

[0049] Next, the storage container 80 constituting the storage object 80A will be described. The storage container 80 is a container for storing semiconductor wafers W, such as a FOSB (Front Opening Shipping Box). Figure 4 As shown, the storage container 80 includes a container body 81 opened at the top and a container cover 82 closing the top of the container body 81 .

[0050] The container body 81 integrally includes a pair of first wall portions 83 , a pair of second wall portions 84 forming side surfaces of the container body 81 together with the pair of first wall portions 83 , and a bottom portion 85 that closes the bottom of the container body 81 .

[0051] The container body 81 includes a plurality of legs 86. The legs 86 are legs that protrude downward from the bottom 85.

[0052] like Figure 2 As shown, a comb-shaped wafer storage section 87 is provided in a container body 81 of the storage container 80 . The wafer storage section 87 has storage grooves formed therein for storing a plurality of semiconductor wafers W at intervals.

[0053] The wafer storage portion 87 includes a side storage portion 87A that contacts the outer edge side portion of the semiconductor wafer W and a bottom storage portion 87B that contacts the outer edge bottom portion of the semiconductor wafer W.

[0054] The side storage parts 87A are arranged in a row on the inner side of the opposing second wall parts 84. Two bottom storage parts 87B are arranged just above the bottom part 85. In each second wall part 84, the two side storage parts 87A are arranged in the direction of the groove arrangement, that is, Figure 2 They are arranged parallel to each other in a direction perpendicular to the paper surface.

[0055] The container cover 82 is a plate-like member having a rectangular planar shape. Figure 4 , Figure 5A ,as well as Figure 5B As shown, there are a pair of locking portions 89 on the front side and a holding portion 91 on the back (inner) side.

[0056] The locking portion 89 is a component for fixing the container cover 82 to the container body 81. Figure 5A As shown, there are locking bars 89A, 89B and a latch mechanism 89C.

[0057] The locking bars 89A and 89B are components provided along the opposite sides of the container cover 82 and can be moved along the Figure 5A Move in the direction of L1 and L2.

[0058] By rotating the latch mechanism 89C, the locking rod 89A can be moved in the L1 direction and the locking rod 89B can be moved in the L2 direction by the cam mechanism. As a result, the front ends of the locking rods 89A and 89B engage with the recessed portion 81A of the container body 81, and the container cover 82 is fixed to the container body 81. In the state where the container cover 82 is fixed to the container body 81, by returning the latch mechanism 89C to the original position, the locking rods 89A and 89B are pulled back to the inner side of the container cover 82, and the container body 81 is released from being fixed.

[0059] like Figure 5B As shown, the holding portion 91 is a longitudinally long comb-shaped member provided on the back side of the container cover 82, and is provided between the locking portions 89. The holding portion 91 is held in the following manner, that is, by inserting the upper peripheral edge of the semiconductor wafer W accommodated in the container body 81 between the teeth of the comb teeth so that it abuts, restricting the axial movement or radial rotation of the semiconductor wafer W, so that the semiconductor wafers W do not contact each other.

[0060] exist Figure 5B In the embodiment, the holding portion 91 is provided in parallel with the arrangement direction of the semiconductor wafers W at the center of the container cover 82 so as to be parallel with one side of the rectangular side constituting the container cover 82 .

[0061] Next, the cushioning materials 1 , 3 , and 5 constituting the cushioning material set 100 will be described.

[0062] The cushioning members 1 , 3 , 5 are made of any one of foamed polyurethane, foamed polyethylene, foamed polypropylene or foamed polystyrene.

[0063] The lower cushioning material 1 constituting the cushioning material group 100 is a cushioning material that supports the lower portion of the storage objects 80A in the row of the storage objects 80A at the lower stage.

[0064] The lower buffer 1 is rectangular and is formed to cover almost the entire surface of the bottom plate 202 of the container 200. The lower buffer 1 has six lower storage parts 11 for storing the lower part of the storage container 80. Three lower storage parts 11 are formed in the X direction and two are formed in the Y direction.

[0065] The lower storage portion 11 is a portion of a shape into which the lower portion of the storage container 80 is fitted. The lower storage portion 11 has a lower opening 12 formed at the center thereof as a rectangular hole formed on the bottom surface of the lower cushioning member 1 .

[0066] The upper cushioning material 5 constituting the cushioning material group 100 is a cushioning material that holds the upper portions of the storage objects 80A in the row of the upper storage objects 80A.

[0067] The upper cushion members 5 are rectangular in shape and are used in a set of two in a packed state, and each upper cushion member 5 covers almost half of the opening of the container 200 .

[0068] The upper cushioning member 5 has three upper storage portions 51. Each upper storage portion 51 holds a container lid 82 of a storage container 80.

[0069] like Figure 1 as well as Figure 2 As shown, two upper cushioning members 5 are stored side by side in a packed state in the container body 201 .

[0070] In the upper housing portion 51 , an upper opening portion 52 which is a rectangular hole penetrating between the upper surface and the lower surface of the upper shock absorbing material 5 is formed at the center of the upper housing portion 51 .

[0071] The middle cushion member 3 is a cushion member that holds the upper portions of the storage objects 80A in the row of the storage objects 80A at the lower stage and supports the lower portions of the storage objects 80A in the row of the storage containers 80 at the upper stage.

[0072] The middle cushion member 3 is rectangular in shape. Similar to the upper cushion member 5, the middle cushion members 3 are used in a set of two in a packaged state.

[0073] The upper surface of the middle buffer 3 (the surface facing upward in the packed state) is formed with three middle body storage parts 31 which are the same as the lower storage part 11 of the lower buffer 1. The lower surface of the middle buffer 3 (the surface facing downward in the packed state) is formed with a middle cover storage part 41 which is the same as the upper storage part 51 of the upper buffer 5.

[0074] The position of the storage object 80A in the packed state is determined by the shape of the cushioning material. The storage object 80A is arranged symmetrically with respect to the center CL in the Y direction.

[0075] Next, refer to Figure 2 and Figure 3 The structure of the vibration absorbing unit 20 will be described.

[0076] The vibration absorbing unit 20 absorbs vibration generated when the object 80A is packed and stored, and includes a first flat plate 21, a second flat plate 22, and a plurality of elastic bodies 23. The vibration absorbing unit 20 is disposed between the lower cushion material 1 and the bottom plate 202 of the container 200.

[0077] The first plate 21 and the second plate 22 are rectangular plate-shaped members slightly smaller than the bottom plate 202 of the container 200. The second plate 22 is disposed on the bottom plate 202 of the container 200, and the first plate 21 is disposed on the second plate 22 via a plurality of elastic bodies 23.

[0078] The second flat plate 22 is parallel to the first flat plate 21 and is disposed below the first flat plate 21. The elastic body 23 is disposed so as to be sandwiched between the first flat plate 21 and the second flat plate 22.

[0079] The first flat plate 21 and the second flat plate 22 are preferably plastic plates with a thickness of 3 mm or more and 25 mm or less, and more preferably plastic plates with a thickness of 8 mm or more and 20 mm or less. The first flat plate 21 and the second flat plate 22 are preferably formed of a hollow structure plate formed of plastic such as a plastic corrugated board. The first flat plate 21 and the second flat plate 22 are not limited to plastic plates, and other plate-like members that are lightweight and have excellent vibration absorption can also be used.

[0080] like Figure 7 As shown, a slot 24 is formed in the first flat plate 21 and the second flat plate 22. The slot 24 of this embodiment is formed substantially in the center of the long side of the flat plates 21 and 22 in the X direction. The slot 24 may also be formed in the short side of the flat plates 21 and 22. The shape of the slot 24 is preferably semicircular, but may also be rectangular or the like.

[0081] In addition, in the present embodiment, the cutouts 24 are formed in the first plate 21 and the second plate 22 , but the present invention is not limited thereto, and it is sufficient as long as the cutouts 24 are formed in at least the first plate 21 of the first plate 21 and the second plate 22 .

[0082] The bending strength of the first flat plate 21 is not less than two times and not more than three times the bending strength of the second flat plate 22 .

[0083] The first flat plate 21 of the present embodiment can be formed of a plastic plate having a bending strength of 2 MPa to 8 MPa. The second flat plate 22 of the present embodiment can be formed of a plastic plate having a bending strength of 1 MPa to 4 MPa.

[0084] The thickness of the first flat plate 21 is the same as that of the second flat plate 22 , and different bending strengths are formed by making the plastic plates of different materials.

[0085] Alternatively, the first plate 21 and the second plate 22 may be made of the same plastic plate and the first plate 21 may be thicker than the second plate 22 , thereby setting the bending strength of the first plate 21 to be 2 to 3 times that of the second plate 22 .

[0086] The elastic body 23 is a cylindrical component that absorbs vibration by elastically deforming relative to vibration. The diameter of the elastic body 23 is greater than 45 mm and less than 85 mm. The height of the elastic body 23 is greater than 25 mm and less than 35 mm. The elastic body 23 can be formed of, for example, polyurethane resin, synthetic rubber, polyethylene, etc., but is preferably formed of polyurethane resin.

[0087] The upper surface and the lower surface of the elastic body 23 are bonded to the flat plates 21 and 22 .

[0088] The number of elastic bodies 23 is the same as the number of storage objects 80A in each layer (six).

[0089] Next, the position where the elastic body 23 is arranged will be described in detail.

[0090] Figure 6 is a cross-sectional view of the vibration absorbing unit 20, Figure 7 is a top view of the vibration absorbing unit. Figure 6 as well as Figure 7 As shown in FIG. 1 , each elastic body 23 is disposed at a position corresponding to the storage object 80A between the pair of flat plates 21 and 22 (at a position substantially the same as the storage object 80A in a plan view). That is, similarly to the storage object 80A, the elastic body 23 is disposed symmetrically with respect to the center CL in the Y direction. The position of the center C1 of the elastic body 23 in the X direction is substantially the same as the position of the center of gravity C2 of the storage object 80A in the X direction.

[0091] In a plan view, the position of the center C1 of the elastic body 23 in the Y direction is different from the position of the center of gravity C2 of the storage object 80A. The center C1 of the elastic body 23 is located outside the center of gravity C2 of the storage object 80A relative to the middle of the two rows of storage objects 80A. The center C1 of the elastic body 23 is located outside the center of gravity C2 of the storage object 80A means that the distance D1 between the center CL in the Y direction and the center C1 of the elastic body 23 is greater than the distance D2 between the center CL in the Y direction and the center of gravity C2 of the storage object 80A.

[0092] When viewed from the row direction (X direction), the distance D in the Y direction (horizontal direction) between the center C1 of the elastic body 23 and the center of gravity C2 of the storage object 80A is not less than 2% and not more than 8% of the diameter of the elastic body 23. If the diameter of the elastic body 23 is 65 mm, the distance in the horizontal direction between the center of the elastic body 23 and the center of gravity of the storage object 80A is about not less than 1.3 mm and not more than 5.2 mm. In the case where the elastic body 23 is cylindrical, the diameter of the elastic body 23 is the maximum outer diameter of the elastic body 23.

[0093] When the elastic body 23 has a polygonal cross section instead of a cylindrical shape, the horizontal distance between the center of the elastic body 23 and the center of gravity of the storage object 80A is 2% to 8% of the maximum outer diameter of the elastic body 23. The maximum outer diameter is the diameter of the circumscribed circle of the polygon.

[0094] Furthermore, when the interval between the elastic bodies adjacent to each other in the X direction is Gx and the interval between the elastic bodies adjacent to each other in the Y direction is Gy, the ratio Gy / Gx between Gy and Gx is in the range of 1 to 1.3.

[0095] [Optimization of the position and number of elastic bodies, bending strength of the flat plate, etc.]

[0096] Next, analysis performed to optimize the positions and number of elastic bodies 23, the bending strength of the plates 21 and 22, and the ratio Gy / Gx of the interval Gy between elastic bodies adjacent in the Y direction and the interval Gx between elastic bodies adjacent in the X direction will be described.

[0097] [Study on the location and number of elastic bodies]

[0098] The inventors believe that the position of the elastic body 23 affects the deflection of the first plate 21 and the tilt of the storage object 80A. In particular, since the upper buffer 5 and the middle buffer 3 are divided in the Y direction, it is believed that the position of the elastic body 23 in the Y direction has a great influence on the deflection of the first plate 21 and the tilt of the storage object 80A, and the displacement (deflection) of the first plate 21 is analyzed by changing the position of the elastic body 23 in the Y direction.

[0099] The position of the elastic body 23 is based on the center of gravity C2 of the storage object 80A, and the center C1 of the elastic body 23 is changed in the Y direction. The X direction position of the elastic body 23 is the same as the X direction position of the storage object 80A and does not change. In addition, the diameter of the elastic body 23 is 65 mm.

[0100] And, if Figure 8 As shown in FIG. 1 , in order to examine the number of elastic bodies 23 , an analysis was also conducted on a case where two elastic bodies 23 were added at the center CL in the Y direction to make the number of elastic bodies 23 eight.

[0101] Fig. 9 It means that in Figure 7 FIG. 2 is a graph showing the displacement amount of the first flat plate 21 when the position of the elastic body 23 in the Y direction is changed in a case where six elastic bodies 23 are arranged. Fig. 9 The horizontal axis is the position (mm) in the Y direction of the first plate 21, and the vertical axis is the displacement in the vertical direction of the first plate 21. In addition, 0 mm in the Y direction is Figure 7 The left end LS, 950mm in the Y direction is Figure 7 The right end of RS.

[0102] like Fig. 9 As shown, when the distance D between the center C1 of the elastic body 23 and the center of gravity C2 of the storage object 80A is 5 mm, the displacement of the first flat plate 21 becomes the smallest. That is, when the position of the center C1 of the elastic body 23 is 5 mm further outside than the position of the center of gravity C2 of the storage object 80A, the deflection of the first flat plate 21 is the smallest.

[0103] Since the diameter of the elastic body 23 is 65 mm, even if the center C1 of the elastic body 23 is positioned 5 mm outside the center of gravity C2 of the storage object 80A, the elastic body 23 is present just below the center of gravity C2 of the storage object 80A, so it is considered that the first flat plate 21 is stably supported.

[0104] On the other hand, when the distance D is 44.5 mm, the first flat plate 21 is bent the most. Since the elastic body 23 has a diameter of 65 mm, the elastic body 23 does not exist immediately below the center of gravity C2 of the storage object 80A, so it is considered that the first flat plate 21 is easily bent.

[0105] Specifically, as the distance D increases to 9.9 mm, 19.9 mm, 23.9 mm, and 44.5 mm, the deflection of the first flat plate 21 increases.

[0106] Furthermore, when the center C1 of the elastic body 23 is positioned further inward than the center of gravity C2 of the storage object 80A, even when the distance D is -0.1 mm, that is, when the elastic body 23 is present immediately below the center of gravity C2 of the storage object 80A, the deflection is larger than when the distance D is 5 mm. When the distance D is -2.5 mm or -5.1 mm, the deflection is further increased.

[0107] Fig.10 It means that in Figure 8 This is a graph showing the displacement amount of the first flat plate 21 when the position of the elastic body 23 in the Y direction is changed in a case where eight elastic bodies 23 are arranged. Fig.10 The horizontal axis represents the position (mm) of the first flat plate 21 in the Y direction, and the vertical axis represents the displacement of the first flat plate 21 in the up-down direction.

[0108] like Fig.10 As shown in FIG. 1 , when the distance D between the center C1 of the elastic body 23 and the center of gravity C2 of the storage object 80A is 53 mm, the displacement of the first flat plate 21 becomes the smallest. This is considered to be the result that by arranging two elastic bodies 23 at the center CL in the Y direction, the first flat plate 21 is less likely to bend even when there is no elastic body 23 immediately below the center of gravity C2 of the storage object 80A.

[0109] According to the above analysis, the distance D between the center C1 of the elastic body 23 and the center of gravity C2 of the storage object 80A is most preferably 5 mm when 6 elastic bodies 23 are arranged, and when 8 elastic bodies 23 are arranged, the distance D is most preferably 53 mm.

[0110] Next, in order to examine the number of elastic bodies 23, a container 200 containing the storage object 80A and the packaging unit 10 was fixed on a vibration tester, and vibration sensors were installed at predetermined positions of the storage container, the pallet, and the vibration table, and a vibration test was performed. The vibration frequency was 5 to 500 Hz, the excitation condition was 0.5 G, and the excitation time was 5 minutes.

[0111] Fig.11 : is the result of the vibration test, and is a graph showing the results of the vibration test under Condition 1, in which the number of elastic bodies 23 is set to 6 and the distance D is set to 44.5 mm, Condition 2, in which the number of elastic bodies 23 is set to 6 and the distance D is set to 5 mm, and Condition 3, in which the number of elastic bodies 23 is set to 8 and the distance D is set to 53 mm. In the vibration test, vibration was excited in the Z direction, and the vibration intensity of the storage container in the Z direction was compared. Fig.11 The “lower layer” is the vibration intensity detected in the storage container at the lower layer, and the “upper layer” is the vibration intensity detected in the storage container at the upper layer.

[0112] like Fig.11 As shown in the figure, when eight elastic bodies 23 are configured, even if the displacement of the first plate 21 can be reduced, the vibration excitation speed in the Z direction becomes larger. This is considered to be mainly because if the number of elastic bodies 23 increases, the rigidity of the vibration absorbing unit 20 as a whole becomes too high and the vibration absorbing capacity decreases. As a result, it was concluded that the number of elastic bodies is preferably six.

[0113] In addition, although condition 1 becomes Fig. 9 The graph showing the displacement of the first flat plate 21 shows the result with a large displacement. However, it can be confirmed that even when the displacement is large, the vibration excitation speed in the Z direction is not greatly affected, but the influence of the quantity is large.

[0114] and, Fig.12 The graphs are the results of vibration tests under conditions 1, 2, and 3, and are graphs comparing the vibration intensity in the X direction of the storage container when the vibration is excited in the Z direction.

[0115] like Fig.12 As shown in the figure, when eight elastic bodies 23 are arranged, even if the displacement of the first flat plate 21 can be reduced, the vibration excitation speed in the X direction of the upper layer becomes larger. This is also considered to be mainly because if the number of elastic bodies 23 increases, the rigidity of the vibration absorbing unit 20 as a whole becomes too high and the vibration absorbing capacity decreases. In this result, it is also concluded that the number of elastic bodies is preferably six.

[0116] Regarding condition 1, it can also be confirmed that the vibration excitation speed in the X direction is not greatly affected, but the influence of the quantity is large.

[0117] When six elastic bodies 23 are arranged, if the distance D is expressed as a ratio to the diameter of the elastic body 23, the distance D is most preferably 8% (≈5 mm / 65 mm) of the diameter of the elastic body 23, which is the upper limit. Fig. 9 It can be seen that since the deflection becomes larger when the distance D is 9.9 mm, the upper limit value is set to exclude this.

[0118] On the other hand, the lower limit of the distance D is set to 2% of the diameter of the elastic body 23. The position of the center C1 of the elastic body 23 is preferably located outside the position of the center of gravity C2 of the storage object 80A. This is to eliminate the possibility that the position of the center C1 of the elastic body 23 becomes inside the position of the center of gravity C2 of the storage object 80A due to manufacturing errors. Fig. 9 It can be seen that since the deflection becomes larger when the distance D is -0.1 mm, the lower limit value is set to exclude this.

[0119] [Study on the bending strength of flat plates]

[0120] Next, in order to examine the strength of the flat plate, a vibration test was performed using two types of first flat plates 21 having different bending strengths.

[0121] Fig.13 The graph is a result of the vibration test, showing the results of the vibration test under condition 2, in which the number of elastic bodies 23 is set to 6, the distance D is set to 5 mm, and the bending strength of the first flat plate is set to 1.5 MPa (the same as the bending strength of the second flat plate), and condition 4, in which the number of elastic bodies 23 is set to 6, the distance D is set to 5 mm, and the bending strength of the first flat plate is set to 3 MPa (twice the bending strength of the second flat plate). In the vibration test, vibration was excited in the Z direction, and the vibration intensity of the storage container in the X direction was compared.

[0122] like Fig.13 As shown in FIG. 1 , when the bending strength of the first flat plate is set to twice that of the second flat plate, although the vibration strength of the upper layer becomes slightly higher, the vibration strength of the lower layer can be improved while improving the deflection amount. This result leads to the conclusion that the bending strength of the first flat plate 21 is preferably twice that of the second flat plate.

[0123] [Optimization of the ratio Gy / Gx of the interval Gy between adjacent elastic bodies in the Y direction and the interval Gx between adjacent elastic bodies in the X direction]

[0124] The ratio Gy / Gx of the interval Gy between adjacent elastic bodies in the Y direction and the interval Gx between adjacent elastic bodies in the X direction is optimized by constructing a vibration analysis model for the container, the packaging unit, the storage object, and the pallet supporting them from below, and performing a frequency response analysis using finite element analysis software.

[0125] Specifically, in the frequency response analysis, a sine wave acceleration with an amplitude of ±0.5G is applied to the pallet supporting the container from below, and the acceleration is calculated to evaluate the response of each component to the external vibration. The frequency range is set to 10Hz to 200Hz, and the frequency interval is set to 1Hz.

[0126] The evaluation index is the effective value RMS (Root Mean Square) calculated by the following formula (1).

[0127] RMS = √(average value of the sum of squares of acceleration at each frequency)...(1)

[0128] In other words, RMS is the root mean square of the acceleration at each frequency.

[0129] In addition, from the analysis results of vibration experiments of storage objects performed in the past, it is known that there is a correlation between the amount of resin attached to the edge of the wafer due to vibration during transportation and the RMS.

[0130] Fig.14 It is a graph showing the correlation between the ratio Gy / Gx and RMS. Fig.14 As shown in FIG. 1 , it was confirmed that the RMS tends to decrease when the ratio Gy / Gx is 1 or more and 1.3 or less.

[0131] According to the above embodiment, the deflection amount of the first flat plate 21 can be reduced by setting the distance D between the center C1 of the elastic body 23 and the center of gravity C2 of the storage object 80A to be 2% or more and 8% or less of the diameter of the elastic body 23. As a result, in the packing unit 10 for packing the storage object 80A in the container 200, the inclination of the storage object 80A can be suppressed, and the storage object 80A or the cushioning member can be stably taken out.

[0132] Furthermore, if the interval between adjacent elastic bodies in the X direction is set to Gx and the interval between adjacent elastic bodies in the Y direction is set to Gy, the ratio Gy / Gx of Gy to Gx is within the range of greater than 1 and less than 1.3, thereby suppressing the vibration of the storage object 80A during transportation, for example, and reducing the amount of resin adhered to the end of the wafer.

[0133] Furthermore, by setting the bending strength of the first flat plate 21 to be not less than two times and not more than three times the bending strength of the second flat plate 22 , it is possible to reduce the vibration intensity during excitation.

[0134] Furthermore, by forming the cutouts 24 in the first flat plate 21 and the second flat plate 22, when taking out the vibration absorbing unit 20, the cutouts 24 can be used to take it out. Thus, the vibration absorbing unit 20 can be easily taken out.

[0135] In the above embodiment, the elastic body 23 is provided in a cylindrical shape, but the elastic body 23 is not limited thereto and may be, for example, in a rectangular parallelepiped prism shape or in a conical shape.

[0136] Furthermore, in the above-described embodiment, the position of the elastic body 23 in the X direction is substantially the same as the position of the center of gravity C2 of the storage object 80A in the X direction, but the present invention is not limited thereto and the elastic body 23 may be offset in the X direction. It is preferred that the elastic body 23 at the center in the X direction is substantially the same as the position of the center of gravity C2 of the storage object 80A in the X direction.

[0137] Furthermore, in the above-mentioned embodiment, the bending strength of the first flat plate 21 is set to be greater than 2 times and less than 3 times the bending strength of the second flat plate 22, but it is not limited to this. As long as the deflection of the first flat plate 21 can be suppressed by optimizing the position of the elastic body 23, for example, the bending strength of the first flat plate 21 can also be made the same as the bending strength of the second flat plate 22.

[0138] Furthermore, the lower shock absorbing member is integrally formed, but may be divided in the width direction similarly to the upper shock absorbing member and the middle shock absorbing member.

[0139] Furthermore, the middle buffer member may be divided in the up-down direction.

[0140] Description of Reference Numerals

[0141] 1-lower buffer, 3-middle buffer, 5-upper buffer, 10-packing unit, 20-vibration absorbing unit, 21-first plate, 22-second plate, 23-elastic body, 80-storage container, 80A-storage object, 81-container body, 100-buffer group, 200-container, 200A-transport container, 201-container body, 202-bottom plate, C1-center, C2-center of gravity, D-distance, W-semiconductor wafer.

Claims

1. A packing unit for packing a storage object, which is a container for storing semiconductor wafers, in a box-type container in a manner that the storage object is divided into two rows at intervals in the width direction and divided into two layers in the vertical direction, the packing unit comprising: A lower buffer member supporting the lower parts of the two rows of storage objects in the lower layer; a middle buffer, one of which is sandwiched between the storage objects at the upper layer and the storage objects at the lower layer in each row of the storage objects; an upper buffer member, one of which is arranged in each of the two rows of storage objects on the upper layer to hold the upper parts of the storage objects; and A vibration absorbing unit supports the lower buffer from below and is disposed at the bottom of the container. The vibration absorbing unit comprises: First slab; a second plate, parallel to the first plate and disposed below the first plate; and elastic bodies, arranged between the first flat plate and the second flat plate, and the number of the elastic bodies is the same as the storage objects in each layer, When viewed from above, the center of the elastomer is located outside the middle of two rows of storage objects and is closer to the center of gravity of the storage objects. The distance in the width direction between the center of the elastomer and the center of gravity of the storage objects is greater than 2% and less than 8% of the maximum outer diameter of the elastomer.

2. The packing unit according to claim 1, wherein: When the interval between the centers of the elastic bodies adjacent to each other in the row direction is Gx and the interval between the centers of the elastic bodies adjacent to each other in the width direction is Gy, a ratio Gy / Gx between Gy and Gx is greater than or equal to 1 and less than or equal to 1.

3.

3. The packing unit according to claim 1 or 2, wherein: The bending strength of the first flat plate is not less than 2 times and not more than 3 times the bending strength of the second flat plate.

4. The packing unit according to claim 1 or 2, wherein: Among the first flat plate and the second flat plate, at least the first flat plate has a cutout formed therein.

5. A transport container, comprising: The packaging unit according to claim 1 or 2; and The box-type container accommodates the packaging unit.

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