JP3918342B2 - Wafer shipping box - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a wafer shipping box for storing a plurality of wafer cases loaded with semiconductor wafers together, and more specifically, with a filter that makes the pressure in the sealed box equal to the external pressure while filtering dust in the atmosphere. The present invention relates to a wafer shipping box.
[0002]
[Prior art]
In order to prevent damage or contamination during transportation, silicon wafers manufactured in a wafer manufacturing factory are usually stored in a wafer case whose lid is sealed with a gasket (packing material).
A plurality of wafer cases are stored together in a large transport box such as a cardboard box called a wafer shipping box so that handling at the time of unloading to a truck, an aircraft, etc. is easy.
A conventional wafer shipping box is a plastic box, and a lid is hermetically sealed with a gasket as in the case of a wafer case.
[0003]
[Problems to be solved by the invention]
Incidentally, as one form of wafer transportation, there is air transportation using an aircraft. At this time, the aircraft on which the wafer is mounted flies at an altitude of several thousand to 10,000 m, and the air pressure in the cargo compartment in the aircraft reaches approximately 0.7 to 0.8 atm. As a result, the wafer shipping box in which air is sealed at normal pressure expands due to the expansion of air due to the difference in atmospheric pressure in the sky at a low atmospheric pressure. As a result, the box is deformed or damaged. Then, due to the differential pressure, air flows out through a small gap between the gaskets that seal the lid and the box body.
[0004]
On the other hand, when the aircraft descends to the ground at normal pressure during landing, the low-pressure air in the box is compressed by a relatively high external pressure and the box contracts due to the atmospheric pressure relationship opposite to that when flying over. Moreover, since the lid is firmly attached to the opening of the box body by the gasket, the outside air does not flow into the box. As a result, the wafer shipping box is deformed as if it was crushed from all sides.
Due to this deformation, depending on the storage position of the wafer case in the box, the wafer case may be deformed by being pushed by the wall plate of the box recessed inward, and the wafer inside may be damaged.
In addition, since the lid is firmly attached to the box body, there is a problem that the lid does not easily open when the lid is opened.
Further, although the shipping box is reused, there is a problem that when the deformation occurs, the reuse cannot be performed.
[0005]
Therefore, it is conceivable to adopt a wafer shipping box having a relatively low sealing performance. However, this makes it easy for air to flow through the gap between the gaskets when flying over a low atmospheric pressure or when the aircraft descends when the atmospheric pressure rises. As a result, it is possible to eliminate wafer damage caused by the box wall plate deformed due to the pressure difference during air transportation, and the lid can be easily opened when the lid is opened after landing, but the lid is poorly sealed. Therefore, when the aircraft descends, dust and dust floating in the aircraft flows into the box through the gap between the gaskets, adheres to the surface of the wafer case, and when the device manufacturer opens and closes this case, There was a risk that the silicon wafer would be contaminated by dust adhering to the case surface.
[0006]
OBJECT OF THE INVENTION
The present invention can automatically release the pressure difference generated inside and outside the box in a relatively short time, thereby preventing deformation of the box due to the pressure difference, and dust outside the wafer case side, Dust adhesion can be prevented, these effects can be obtained at a relatively low cost, the box can be reused, and external impacts are not easily transmitted to the semiconductor wafer housed in the wafer case. The object is to provide a wafer shipping box.
Another object of the present invention is to provide a wafer shipping box having a high filterability for fine garbage.
A further object of the present invention is to provide a wafer shipping box that can be stacked in a safe and reliable manner.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a wafer shipping box for storing and transferring a plurality of wafer cases in which semiconductor wafers are stored, and the wafer shipping box has a lid and a bottom surface of the box body when sealed. Each of the above wafers is made of metal in a parallel flat box shape, and the surface of the box body is smoothed in order to prevent generation of dust from the surface through a cushioning material made of synthetic resin foam. A case is housed, and a filter is provided on the outer wall of at least one of the box body and the lid so as to communicate the inside and outside of the wafer shipping box. The buffer material houses each wafer case in a buried state. A plurality of storage pockets are formed with openings on the upper surface of the cushioning material, and the upper surface of the cushioning material is between the lid and the cushioning material. A wafer shipping box space is formed over the frequency range.
[0008]
The type of semiconductor wafer is not limited. For example, a silicon wafer or a gallium arsenide wafer may be used. Further, the size of the semiconductor wafer is not limited. For example, an 8-inch wafer, a 300 mm wafer, etc. are mentioned. The present invention is a metal box having higher strength than conventional cardboard or plastic. This is an effective technique especially for a large-diameter wafer such as a 300 mm wafer that is bulky.
Further, the structure, size, shape and material of the wafer case are not limited. A general wafer case has a container body in which a wafer is stored and a lid for the container body. Examples of materials for these members include various plastics such as polycarbonate, polyethylene, polypropylene, polystyrene, PEEK, PBT, PVC, and PMMA.
[0009]
The outer shape of the wafer shipping box may be a flat box. For example, it may be a circular or elliptical box in plan view, a triangular, quadrilateral, pentagonal, hexagonal or more polygonal box in plan view, or a box of any shape other than the above in plan view.
The material of the box body and the lid is not limited as long as it is a metal. Examples include hard aluminum, iron, stainless steel, and brass. Among these, hard aluminum which is a relatively light and high strength material is preferable.
The material of the cushioning material is a synthetic resin foam. Specific examples of the synthetic resin foam include polystyrene foam and urethane foam. Among these, in the case of polystyrene foam, only the surface layer portion having the fine irregularities is melted to improve the smoothness of the surface.
[0010]
The size, shape and number of storage pockets are not limited. The size and shape of the pocket vary depending on the size and shape of the wafer case. Further, the number of formations usually increases or decreases according to the size of the wafer shipping box, specifically, the volume of the box body.
The plurality of storage pockets need to be arranged side by side in the box body. By arranging side by side, this box becomes a flat box with relatively low bulk. However, the arrangement is not limited. For example, it may be regularly arranged along the surface of the cushioning material, or may be irregularly arranged. Examples of the regular arrangement include a single-row arrangement and a multi-row arrangement. Moreover, you may arrange in a matrix form.
[0011]
The kind and material of the filter are not limited. As the material, for example, a known filter such as a membrane filter made of various synthetic resins such as nitrocellulose, cellulose acetate, tetrafluoroethylene resin (PTFE), and hydrophilic tetrafluoroethylene resin can be employed. In addition, the membrane filter is usually a plastic thin film having a thickness of 0.1 to 0.2 mm, in which a large number of fine holes having a certain size are formed.
The average pore diameter of the filter is not limited as long as it is a size that can filter dust floating in the atmosphere. Further, the external dimensions of the filter are not limited as long as the filter can withstand the pressure difference between the inside and outside of the case.
Furthermore, the assembly position of the filter may be any part of the box body or the outer wall of the lid. Moreover, you may assemble | attach to both members. Further, the number of assembled filters is not limited. This filter can be replaced at the time of reuse, thereby extending the reuse life of the shipping box.
[0012]
A second aspect of the present invention is the wafer shipping box according to the first aspect, wherein the filter is a filter capable of filtering garbage having a size of 0.2 μm or more.
[0013]
According to a third aspect of the present invention, the upper surface of the lid and / or the bottom surface of the box body has a fitting structure for fitting with the wafer shipping box arranged at the upper stage and / or the wafer shipping box arranged at the lower stage. A wafer shipping box according to claim 1 or 2.
The portion of the box in which the fitting structure is provided may be a predetermined portion of the lid, the bottom portion of the box body, or both of these portions. The shape of the fitting structure is not limited. Generally, it is comprised from a simple convex part and a recessed part or a protrusion and a groove | channel.
[0014]
[Action]
According to the first to third aspects of the present invention, when the external atmospheric pressure changes for some reason, for example, when a pressure difference occurs inside and outside the wafer shipping box sealed with the packing material, In this box, air flows from the higher pressure to the lower pressure. Thereby, the pressure difference inside and outside the box is automatically released. Therefore, the deformation of the wafer case due to the box deformation due to the pressure difference, and the damage of the semiconductor wafer in the case can be prevented.
In addition, fine dust and dust in the atmosphere are filtered and removed by a filter. For this reason, when this pressure difference is released, dust and dust floating in the atmosphere unlike conventional means do not adhere to the surface of the wafer case in the box. In addition, structurally, since the filter is simply attached to the wafer shipping box, these effects can be obtained at a relatively low cost.
[0015]
In particular, according to the invention described in claim 2, since a filter capable of filtering wastes having a size of 0.2 μm or more is employed as the filter, when the pressure difference between the inside and outside of the case is released, Can be filtered with fairly fine trash.
[0016]
According to the third aspect of the present invention, when the wafer shipping boxes are stacked, they are stacked via the fitting structure provided on the bottom of the lid and / or the box body. Since the upper and lower boxes are firmly integrated by the fitting structure, the wafer shipping box can be stacked safely and securely, and higher than when the boxes are simply stacked.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
A wafer shipping box according to an embodiment of the present invention will be described below.
FIG. 1 is a perspective view of the wafer shipping box according to one embodiment of the present invention in an open state. FIG. 2 is a perspective view showing a closed state of the wafer shipping box according to one embodiment of the present invention. FIG. 3 is a perspective view showing a stacked state of wafer shipping boxes according to one embodiment of the present invention.
In FIG. 1, reference numeral 10 denotes a wafer shipping box according to an embodiment of the present invention. This wafer shipping box 10 is a silicon wafer W (φ300 mm wafer) obtained by slicing, chamfering the outer edge, lapping, etching, and polishing after cutting a silicon ingot produced by the CZ method into a predetermined size. A total of six wafer cases 11 to be stored one by one are respectively stored in storage pockets 12 in the box. Hereinafter, each component will be described in detail.
[0018]
First, the wafer case 11 includes a container main body 13, a lid 14 that closes an opening on the upper surface of the container main body 13, and packing interposed between the outer walls of the container main body 13 and the opening peripheral edge of the lid 14. And an annular rubber gasket 15 which is an example of the material. As the material for the container body 13 and the lid 14, transparent or translucent polypropylene and polycarbonate are used.
As shown in FIGS. 1 and 2, the wafer shipping box 10 includes a box body 16 having a length of 1900 mm × a width of 1300 mm × a height of 700 mm, and a gasket 17 made of the same material as the gasket 15 interposed in the box body 16. And a lid 18 that is pivotally attached to be freely opened and closed.
The wafer shipping box 10 is a flat box in which aluminum, duralumin, or the like is employed as a material for the box body 16 and the lid 18, and the bottom surface of the box body 16 and the top surface of the lid 18 are parallel. The gasket 17 is a flexible frame member having a rectangular shape in plan view with a width of 10 mm and a height of 10 mm.
[0019]
Inside the box body 16, a cushioning material 19 made of styrene foam having a thickness of 200 to 220 mm is loaded. The surface of the buffer material 19 is subjected to a smoothing process in which only the surface layer portion on which fine irregularities appear is once melted and then cooled. This makes it difficult for the foamed polystyrene to be generated from the surface of the cushioning material 19. The lid 18 has a length of 1900 mm × width of 1300 mm × height of 300 mm. Further, a male fitting portion 16a (one fitting structure) for fitting with another wafer shipping box 10 arranged in a lower stage is provided on the bottom portion of the box body 16 except for the outer peripheral portion of the bottom surface thereof. Yes. In addition, a female fitting portion 18a (the other fitting structure) that fits with the male fitting portion 16a of another wafer shipping box 10 disposed in the upper stage is formed in the upper plate of the lid 18 so as to be recessed. That is, the wafer shipping boxes 10 arranged in the upper and lower stages are fitted via the male and female fitting portions 16a and 18a in order to stabilize the stacked state. The box body 16 and the lid 18 are sealed so that the lid can be opened and closed by a known sealing means.
[0020]
A total of six storage pockets 12 are recessed in the cushioning material 19, three in front and two in a row. Each storage pocket 12 has a size of 410 mm long × 340 mm wide × 300 mm high. In addition, the gap between the storage pockets 12 is 220 mm both vertically and horizontally. Further, the total weight of the wafer shipping box 10 when the wafer case 11 storing the specified number of 300 mm wafers W is stored in each storage pocket 12 is about 8 kg.
At both ends of the front plate of the box body 16, a pair of filters 20 that communicate between the inside and the outside of the box are provided. Note that only one filter 20 may be provided at one end of the front side plate. This filter 20 is made of PTFE, and can filter fine garbage having a size of 0.2 μm or more. The housing of the filter 20 is made of polypropylene.
Specific dimensions and performance of the filter 20 are a diameter of 50 mm, an average pore diameter of 0.2 μm, and a pressure strength (at 25 ° C.) of 2.1 kg / cm ² . The filter 20 has a filtration rate of 15 liters / min.
[0021]
Next, the wafer shipping box 10 according to this embodiment is circulated between the wafer manufacturing factory and the device manufacturer as follows. That is, first, the wafer shipping box 10 is inspected for damage and dirt adhering.
Next, as shown in FIG. 1, first, in each of the six storage pockets 12, the wafer cases 11 preliminarily loaded with a prescribed number of silicon wafers W are respectively stored. The opening is sealed by the lid 18. Note that the lid 18 is closed at normal pressure.
Then, as shown in FIG. 3, the sealed wafer shipping boxes 10 are sequentially stacked on a pallet 21 for transportation so as to be easily handled by a forklift not shown. At this time, the wafer shipping box 10 arranged at the lower stage and the wafer shipping box 10 arranged at the upper stage are fitted with the male fitting part 16a on the upper stage side to the female fitting part 18a on the lower stage side, Stacked.
[0022]
As a result, the stacked wafer shipping boxes 10 are firmly integrated by the fitting structures 16a and 18a. As a result, it is possible to stack the wafer shipping boxes 10 safely and reliably and higher than when they are simply stacked.
FIG. 3 illustrates a three-stage stacking of wafer shipping boxes 10. However, it is not limited to this. For example, in the case of one-stage stacking or two-stage stacking, four-stage stacking or more may be used. Further, the stacked wafer shipping boxes 10 are less likely to collapse when fastened using the strings 22.
[0023]
Thereafter, the stacked wafer shipping boxes 10 are mounted on an aircraft and transported by air to a factory of a device manufacturer. This case will be described below. Using a forklift (not shown), the stacked wafer shipping boxes 10 are carried into the aircraft via the pallet 21. After that, by taking these items by air, after taking off, they will fly at an altitude of several thousand to 10,000 m (atmospheric pressure 0.7 to 0.8 atm).
That is, in the sky with a low atmospheric pressure, a pressure difference of 0.2 to 0.3 atmosphere occurs between the case sealed at normal pressure and the outside of the case with a low atmospheric pressure. At this time, a filter 20 is attached to each wafer shipping box 10. As a result, the air in the box flows out of the box through the filter 20 until the atmospheric pressure becomes substantially equal even though the lid 18 is sealed, and the pressure difference between the inside and outside of the box is automatically released. .
[0024]
Further, when the aircraft descends for landing and the external pressure rises, the outside air tends to flow into the box having a low atmospheric pressure. Here, when the filter 20 is not provided in the box, the lid 18 is pressure-bonded to the opening of the box body 16 due to the presence of the gasket 17 that keeps hermeticity, causing the box deformation, and the stored wafer case 11 is also deformed. As a result, the silicon wafer W in the case may be damaged.
However, in the case of this embodiment having the filter 20, the external air flows into the box through the filter 20, and the pressure difference inside and outside the box is automatically released. As a result, the deformation of the wafer shipping box 10 which has conventionally been caused by the pressure difference between the inside and outside of the box can be eliminated, and the deformation / damage of the wafer case 11 due to this deformation, and thus the damage of the silicon wafer W in the case can be prevented. be able to. In addition, the shipping box can be reused.
[0025]
As a result, when the pressure difference is released, dust or dust floating in the atmosphere as in the conventional means adheres to the surface of the wafer case 11 in the box, or directly adheres to the surface of the silicon wafer W in the case. There is nothing to do. In addition, since the structure is a simple one in which the filter 20 is simply attached to the wafer shipping box 10, these effects can be obtained at a relatively low cost.
In particular, the filter 20 is a filter that filters fine dust having a size of 0.2 μm or more. Therefore, when the pressure difference between the inside and outside of the case is released, it is possible to filter with a very fine dust in the atmosphere.
[0026]
Thereafter, in the device manufacturer, each wafer case 11 is taken out from the wafer shipping box 10, and then the empty wafer shipping box 10 is temporarily stored in the stock yard. Next, it is returned to the wafer manufacturing plant again on an aircraft or the like. Then, in this factory, the returned wafer shipping box 10 is inspected, cleaned, and re-inspected, and then the wafer case 11 is packed into the wafer shipping box 10.
[0027]
As mentioned above, although one Example of this invention was described, this invention is not limited to this Example, The design change is included in the range which does not deviate from the summary.
For example, as shown in the perspective view of the opening state of the wafer shipping box according to another embodiment of FIG. 4, the wafer shipping box 30 is formed, and the four storage pockets 12 are formed in the cushioning material 19 so as to be recessed. It is good also as a small box which can store only four pieces. Here, one filter 20 is used. The size of the four box 30 is 1300 mm long × 1300 mm wide × 700 mm high.
[0028]
【The invention's effect】
In the first to third aspects of the invention, the wafer shipping box is a metal flat box, a buffer material with a plurality of storage pockets is provided in the box body, and the inside and outside of the box communicate with each other. Since a filter is provided, automatic release of the pressure difference between the inside and outside of the box in a short time, prevention of wafer damage due to box deformation, prevention of dust and dust from adhering to the wafer surface, and cost reduction of these effects can be achieved simultaneously. . In addition, the box can be reused and the impact from the outside does not easily propagate to the wafer side.
[0029]
In particular, according to the invention described in claim 2, since a filter capable of filtering fine dust having a size of 0.2 μm or more is employed as a filter, when releasing the pressure difference between the inside and outside of the case, It can be filtered with fairly fine garbage.
[0030]
According to the third aspect of the present invention, since the fitting structure is provided at the bottom of the lid and / or the box body, the wafer shipping box can be stacked more safely and reliably than when it is simply stacked. .
[Brief description of the drawings]
FIG. 1 is a perspective view of a wafer shipping box according to an embodiment of the present invention in an open state.
FIG. 2 is a perspective view showing a closed state of the wafer shipping box according to one embodiment of the present invention.
FIG. 3 is a perspective view showing a stacked state of wafer shipping boxes according to one embodiment of the present invention.
FIG. 4 is a perspective view showing an open state of a wafer shipping box according to another embodiment of the present invention.
[Explanation of symbols]
10, 30 Wafer shipping box,
11 Wafer case,
12 storage pockets,
16 box body,
16a male fitting part (fitting structure),
18 lid,
18a Female fitting part (fitting structure),
19 cushioning material,
20 filters,
W Silicon wafer (semiconductor wafer).

Claims (3)

A wafer shipping box for storing and transferring a plurality of wafer cases in which semiconductor wafers are stored,
This wafer shipping box is made of metal in a flat box shape in which the lid and the bottom of the box body are parallel when sealed.
In the box body, each of the wafer cases is housed via a cushioning material made of a synthetic resin foam whose surface is smoothed to prevent the generation of dust from the surface,
A filter is provided on the outer wall of at least one of the box body and the lid to communicate the inside and outside of the wafer shipping box,
In the cushioning material, a plurality of storage pockets for storing the wafer cases in an embedded state are formed with openings on the upper surface of the cushioning material,
A wafer shipping box in which a space is formed across the entire upper surface of the cushioning material between the lid and the cushioning material .   The wafer shipping box according to claim 1, wherein the filter is a filter capable of filtering garbage having a size of 0.2 μm or more.   The upper surface of the lid and / or the bottom surface of the box body has a fitting structure that fits with a wafer shipping box arranged in an upper stage and / or a wafer shipping box arranged in a lower stage. The described wafer shipping box.

Images