JPWO2009107254A1 - Wafer storage container with back support structure - Google Patents

Abstract

The present invention provides a wafer storage container that does not come into contact with the surface side of a semiconductor wafer on which devices are formed. The wafer storage container of the present invention has a storage container body, a lid, a storage container body, a seal, and a wafer support that is formed inside the storage container body and aligns and supports the wafer, and the wafer support supports the shelf. A plate part, a plurality of shelves for aligning and supporting a plurality of wafers in the axial direction at predetermined intervals, a support plate mounting part, a mounting protrusion for supporting the back surface of the wafer on the top surface of the shelf, and a plurality of wafers having a diameter It has a restricting portion that restricts in the direction, and has one or more holes in the shelf. The shelf is inclined to the upper side of the wafer central axis and has shelf reinforcing ribs.

Description

  The present invention relates to a wafer storage container used for transporting or storing semiconductor wafers.

As for the size of the semiconductor wafer, the standard for wafers of up to 450 mm is now being examined, and the diameter of semiconductor wafers is becoming larger and larger. However, since the thickness of the semiconductor wafer is not so thick, handling of the semiconductor wafer during the semiconductor device manufacturing process Careful consideration is required in a wafer storage container for storing semiconductor wafers. Also, the minimum pattern of the semiconductor device has become 50 nm or less. In such a semiconductor wafer on which a device with a design rule of 100 nm or less is mounted as the miniaturization progresses, the presence of particles generated during the process causes a fatal defect in the pattern on the wafer. Therefore, it is necessary to completely prevent even very small particles in the atmosphere where the semiconductor wafer is held. Particularly in the wafer storage container, it is necessary to minimize the contact between the semiconductor wafer and the wafer storage container, and to eliminate particles generated by the contact. Conventionally proposed or used wafer storage containers use a semiconductor wafer in which the peripheral edge of the semiconductor wafer is pressed by a V-groove or U-groove. (Patent Document 1) Alternatively, a method has been proposed in which an edge side surface portion of a semiconductor wafer and a semiconductor wafer back surface peripheral edge portion are pressed. (Patent Document 2)
JP 2002-353301 A Joto-3030287

  As shown in Patent Document 1, when the wafer support portion of the wafer storage container is a V-groove, the periphery of the wafer is pressed by the V-groove, and the wafer support portion is the surface of the semiconductor wafer on which the device is formed. In contact with the peripheral edge of the wafer. As a result, the thin film (oxide film, nitride film, metal film, etc.) formed on the surface of the semiconductor wafer at the wafer peripheral part is slightly peeled off and forms a device that exists inside the wafer peripheral part as particles. Or adhere to the formed (or formed) surface. Alternatively, the above problem may be caused by a slight peeling of the wafer support (made of a polymer material) in contact with the peripheral edge of the wafer. Furthermore, it is natural that the wafer front side is supported only by the wafer peripheral edge, but the wafer back surface is also supported only by the wafer peripheral edge, so that the wafer surface (especially when the wafer has become larger in diameter) The wafer is bent by its own weight, and the stability of the wafer is deteriorated. In particular, when a wafer is taken in and out of the storage container, there is a high possibility that the wafer is inclined and damaged. Further, the wafer stored in the storage container may be broken due to repeated wafer deflection vibration. Furthermore, there is a possibility that the wafers come into contact with each other in the wafer storage container to damage the device, or particles due to the contact may be generated.

  In the method for supporting a semiconductor wafer shown in Patent Document 2, the peripheral edge of the semiconductor back surface is in contact with the storage container, so that particles generated by this contact wrap around the semiconductor surface and adhere to the semiconductor surface. . Alternatively, they adhere to the surface of another semiconductor wafer placed underneath. As a result, pattern defects occur and the yield and characteristics of the semiconductor device are degraded.

The present invention provides a wafer storage container that not only can prevent damage to a semiconductor wafer due to impact during transportation but also can be safely and easily taken out without damaging the semiconductor wafer. The purpose is to do. It is another object of the present invention to provide a wafer storage container that can minimize particles generated in the wafer storage container.

  In order to achieve the above object, a wafer storage container according to the present invention includes a storage container body having at least one opening, a lid for closing the opening, and the storage container body when the storage container body is closed by the lid. A seal for airtightly isolating the interior of the container body from the external environment; and a wafer support formed in the storage container body for supporting the wafer in alignment. A plurality of shelves that are aligned and supported in the axial direction at intervals, a support plate portion that supports the shelf, a support plate attachment portion for attaching the support plate portion to the inside of the storage container body, and the support plate portion And a restriction portion for restricting the plurality of wafers formed in the radial direction in the radial direction, and one or more holes are formed inside the shelf. In addition, the shelf is formed on the upper surface of the shelf (on the side where the wafer is placed and on the side in contact with the back surface of the wafer), and one or a plurality of placements for supporting and placing the back surface of the wafer. Has protrusions.

  Further, the restricting portion is in contact with the semiconductor wafer only at the side end top portion of the semiconductor wafer or only at the side end top portion of the semiconductor wafer and the bevel portion of the semiconductor wafer. Further, the restricting portion is characterized in that the boundary with the shelf is inclined (the portion contacting the lower part of the bevel on the back surface of the semiconductor wafer is inclined). The wafer support is formed of a pair of opposing mirror image structures having a bilateral reference plane as a symmetry plane in the wafer storage container.

  By using the wafer support of the present invention, the semiconductor wafer can be supported by a minute portion inside the wafer peripheral portion on the back surface of the wafer without contacting the wafer peripheral portion on the back surface of the wafer. Therefore, particles or the like that wrap around from the back surface side of the semiconductor wafer to the front surface side of the semiconductor wafer can be extremely reduced. Further, since the inner surface of the back surface of the wafer is further supported by the mounting protrusions, the amount of deflection of the wafer can be minimized. In particular, in the case of a large-diameter wafer, since the amount of deflection of the wafer becomes large, the effect of the wafer support of the present invention is great. Moreover, the fact that the amount of deflection can be reduced leads to a reduction in the wafer pitch stacked on the wafer storage container, and as a result, the number of wafers that can be stored in the wafer storage container can also be increased. Furthermore, when the semiconductor wafer is taken in and out, the semiconductor wafer is (is) placed on the plurality of placement protrusions, so that the semiconductor wafer can be stably placed horizontally. As a result, the semiconductor wafer is not damaged.

  Furthermore, the structure of the restricting portion is configured such that only the wafer-side end top portion or the wafer-side end top portion and the wafer bevel portion are in contact with the wafer, whereby the surface of the semiconductor wafer on which the semiconductor device is formed is The semiconductor wafer can be stored and stored in the semiconductor wafer storage container without any contact including the peripheral edge of the semiconductor wafer. The back surface of the semiconductor wafer is formed on the plurality of shelves that are formed inside the storage container main body and support the wafers in alignment with each other. The semiconductor wafer is fixed on the plurality of mounting protrusions formed by pressing the wafer-side top of the semiconductor wafer or the wafer-side top and bevel of the semiconductor wafer. The force that holds the semiconductor wafer from the restricting portion acts strongly in the direction from the periphery to the center of the semiconductor wafer, that is, in the direction parallel to the plane of the semiconductor wafer, so that the semiconductor wafer is not damaged and the semiconductor wafer is also fixed. Surely done.

The shelf projects toward the center of the storage container and is not fixed from the center side, but has one or more holes on the inside (inside) of the shelf (annular structure with holes) ) And at least the arms (lever) on both sides can reduce the weight of the shelf itself and suppress the decrease in support strength. Bending can be minimized. The shelf also serves as a guide for standing the semiconductor wafer upright when the wafer storage container is placed vertically (with the opening facing up).

  The semiconductor wafer enters between the shelves, but only the side edge top of the semiconductor wafer, or only the side edge top of the semiconductor wafer and the back side of the semiconductor wafer (especially the lower part of the bevel) is in contact with the regulating part. Since the inside of the peripheral edge of the semiconductor wafer on the surface of the semiconductor wafer is not in contact, particles that may be generated if contacted are not generated. As a result, no defect is generated on the device on the surface of the semiconductor wafer (or a region formed in the future). Therefore, the growth of the insulating film, conductor film and semiconductor film by thermal oxidation, CVD (chemical vapor deposition) method, PVD (physical vapor deposition) method, etc. is completely performed on the peripheral edge or bevel top of the semiconductor wafer. Since it is difficult to prevent this, conventionally, it was necessary to add a process for removing these thin films adhering to the peripheral edge of the wafer. However, when using the wafer storage container of the present invention, such a thin film removing process is required. It is not always necessary to enter. Furthermore, even when a photoresist is applied to the semiconductor surface, the step of removing the photoresist on the peripheral edge of the wafer on the surface side of the semiconductor wafer (so-called edge rinse) can be omitted.

  Further, when there is no shelf for supporting the back surface of a wafer having a large diameter whose thickness is not so thick as required to make the semiconductor wafer as thin as possible, only the side top of the semiconductor wafer or the semiconductor wafer Although it is very difficult to fix the semiconductor wafer in a state where only the side end top portion and the back surface side of the semiconductor wafer (particularly the lower part of the bevel) are in contact with the regulating portion, in the wafer storage container of the present invention, the back surface of the semiconductor wafer is also a shelf. Therefore, the semiconductor wafer can be fixed.

  Furthermore, there is a demand that it is not desired to contact a part of the wafer storage container with the peripheral edge of the back surface of the semiconductor wafer. This is because it is desired to prevent as much as possible particles and the like generated at the contact portion between the semiconductor wafer and the wafer storage container (for example, the support portion) on the back surface of the semiconductor wafer from entering from the back surface and adhering to the semiconductor wafer surface. Conventionally, in the case of supporting the back surface of the semiconductor wafer, since the peripheral edge portion of the back surface of the semiconductor wafer is supported, the above-mentioned problems cannot be overcome. Since the shelf of the wafer storage container of the present invention has one or a plurality of holes inside the shelf (or is a holed annular structure), the weight of the shelf can be reduced. It becomes possible to extend to the center side of the wafer storage container. For example, because the inside of the shelf is in a perforated state, the load applied to the base between the shelf and the support plate can be reduced by dispersing it, and the tip of the shelf can be extended far from the base. it can. As a result, the wafer can be fixed without being brought into contact with the peripheral edge of the wafer by placing the wafer on the mounting protrusion located at some distance from the peripheral edge of the wafer.

FIG. 1 is a perspective view showing the inside of a wafer storage container main body according to an embodiment of the present invention in a cross-sectional state. FIG. 2 is a perspective view showing a wafer storage container according to the embodiment of the present invention. FIG. 3 is a perspective view showing the wafer support according to the embodiment of the present invention. FIG. 4 is a plan view showing one half of a wafer storage container in which a wafer support and a semiconductor wafer according to an embodiment of the present invention are set. FIG. 5 is a plan view showing one half of a wafer storage container in which a wafer support and a semiconductor wafer according to another embodiment of the present invention are set. FIG. 6 is a plan view showing one half of a wafer storage container in which a wafer support and a semiconductor wafer according to another embodiment of the present invention are set. FIG. 7 is a plan view showing one half of a wafer storage container in which a wafer support and a semiconductor wafer according to another embodiment of the present invention are set. FIG. 8 is a plan view showing one half of a wafer storage container in which a wafer support and a semiconductor wafer according to another embodiment of the present invention are set. FIG. 9 is a view showing a restricting portion and a shelf in the wafer support of the present invention. FIG. 10 is a perspective view showing the wafer pressing member. FIG. 11 is a plan view showing the wafer pressing member. FIG. 12 is an enlarged plan view of the peripheral portion of the edge of the semiconductor wafer. FIG. 13 is a perspective view showing another wafer support according to the embodiment of the present invention. FIG. 14 is a view showing a wafer storage container having an inclined shelf. FIG. 15 is a view showing a shelf having another shape according to the present invention. FIG. 16 is a view showing a wafer storage container having a shelf having shelf reinforcing ribs. FIG. 17 is a view showing a wafer storage container having a shelf having shelf reinforcing ribs. FIG. 18 is a view showing a wafer storage container having a rear shelf. FIG. 19 is a diagram for explaining the state of the inclined shelf. FIG. 20 is a perspective view showing a state of a shelf provided with shelf reinforcing ribs. FIG. 21 is a diagram for explaining a state of insert molding of the wafer support. FIG. 22 is a diagram showing another embodiment of the wafer support.

Explanation of symbols

1 Wafer storage container, 2 Wafer storage container body, 3 Wafer support, 4 Lid,
5 Top flange, 6 Carrying handle, 50 Shelf,
51 (wafer support) support plate part, 52 mounting projection, 54 handle, 55 upper fitting part,
56 lower fitting part, 58 upper mating piece, 62 support plate piece, 63 plate material,
65 positioning means, 66 positioning means, 67 longitudinal positioning means,
69 Lower plate part, 71 Notch, 73 Front / rear direction support plate piece, 75 Stopper,
76 locking pieces, 76A elastic plate pieces, 76B locking claws, 311 storage container body,
312 (wafer support) support plate portion, 313 shelf, 314 regulating portion,
319 mounting protrusion, 331 storage container body, 332 (wafer support) support plate,
333 (wafer support) support plate portion, 334 shelf, 335 shelf,
336 mounting protrusion, 337 mounting protrusion, 338 wafer support front mounting portion,
339 Storage container body, 340 Wafer support rear mounting part, 341 Storage container body,
342 (wafer support) support plate part, 343 shelf, 344 regulating part,
345 Upper mounting portion, 346 Central mounting portion, 347 Lower mounting portion, 349 Mounting protrusion,
361 (wafer support) support plate portion, 364 (wafer support) support plate portion,
371 Shelf reinforcing rib, 372 Shelf reinforcing rib, 373 Shelf reinforcing rib,
374 Shelf reinforcing rib, 381 (wafer support) support plate,
384 (wafer support) support plate,
391 (391-1, 391-2) shelf reinforcing ribs,
392 (392-1, 392-2) shelf reinforcing ribs,
393 (393-1, 393-2) shelf reinforcing ribs,
394 (394-1, 394-2) shelf reinforcing ribs,
395 Rear (wafer support) support plate portion, 396 Rear shelf, 397 mounting protrusion, 398 Rear wafer support mounting portion,
399 (399-1, 399-2) shelf reinforcing ribs,
511 (wafer support) support plate portion, 512 regulating portion, 513 shelf,
514 Placement protrusion, 515 Shelf reinforcement rib, 521 (wafer support) support plate part, 522 Shelf, 523 Placement protrusion, 524 Shelf reinforcement rib, 525 Restriction part,
601 storage container body, 602 (wafer support) support plate, 603 shelf,
604 mounting protrusion, 610 wafer support, 611 support plate part, 612 regulating part,
613 shelf, 614 mounting protrusion, 615 arm part, 616 belt-like part,

  In the present invention, the surface side of the semiconductor wafer on which the semiconductor device is formed is not in contact at all, and only the side edge top portion of the semiconductor wafer or only the side edge top portion of the semiconductor wafer and the bevel portion of the semiconductor wafer is contacted, Provided is a wafer storage container for storing a plurality of semiconductor wafers, which has a structure that does not contact the peripheral edge of the semiconductor back surface.

  As for the size of the semiconductor wafer, a standard of a maximum of 450 mm is now being examined, and the diameter of the semiconductor wafer is gradually increasing. Also, the minimum pattern of the semiconductor device has become 50 nm or less. In such an ultra-fine pattern, it is necessary to completely prevent even very small particles and outgas in the atmosphere in which the semiconductor wafer is held. In particular, in a wafer storage container in which semiconductor wafers are always stored, it is necessary to minimize contact between the semiconductor wafer and the wafer storage container and to eliminate particles generated by the contact.

  FIG. 12 is an enlarged view schematically showing the peripheral portion of the edge of the semiconductor wafer. The surface 105 side of the semiconductor wafer 101 includes a flat region X and an edge region Y. A semiconductor device is formed in the flat region X. However, in general, a semiconductor device including an active element such as a transistor and a passive element such as a resistor is formed inside a certain distance W (device forming region indicated by 107) from the boundary between X and Y. This is because the above-described defects due to particles and the like are prevented in addition to restrictions from process conditions such as thin film formation, etching process, and photolithography. Normally, W is 3 to 7 mm. However, in recent years, W has become smaller due to progress in process technology and higher performance of semiconductor devices. The edge region Y includes an inclined portion 103 and a wafer side top portion 102 which is the outermost part of the wafer edge. On the other hand, the back surface 106 side of the semiconductor wafer 101 is also composed of a flat region X ′ and an edge region Y ′. The edge region Y ′ includes an inclined portion 104 and a wafer side end top portion 102 which is the outermost part of the wafer edge. In the present application, the inclined portion 103 on the semiconductor surface side is referred to as a bevel upper portion, and the inclined portion 104 on the semiconductor back surface side is referred to as a bevel lower portion. As described above, in the ultrafine process in recent years, it is required that nothing should come into contact with the semiconductor wafer surface side, that is, the X portion or the bevel upper portion 103 in the wafer storage container.

  In order to support and fix the semiconductor wafer to the storage container, the semiconductor wafer and the wafer storage container must be in contact with each other. However, at the side edge top portion 102 that is the outermost part of the wafer edge Y, the semiconductor wafer must be at least in contact. Absent. Furthermore, the bevel lower part 104 on the semiconductor back surface side connected to the side end top part 102 must be brought into contact to some extent. (If the bevel upper portion 103 cannot be contacted, the contact is made to the bevel lower portion 104.) If the semiconductor wafer has a small diameter and is quite thick and has sufficient strength, the semiconductor is only contacted by the side edge top portion and the bevel lower portion. If the wafer is pressed firmly from the edge side, it can be supported and fixed to the wafer storage container, but even if the semiconductor wafer becomes large in diameter, the thickness of the semiconductor wafer is not so thick (and this trend will continue in the future) In the situation where the strength of the semiconductor wafer is further reduced after the semiconductor wafer is polished and thinned, it is stored only by contact of only the side edge top portion 102 and the bevel lower portion 104 of the semiconductor wafer with the wafer storage container. The semiconductor wafer is not sufficiently supported and fixed in the container. Ha semiconductor wafer may possibly be broken in and during transfer of the container during transport. Therefore, the semiconductor wafer must be allowed to contact the back surface 106 side. However, as described above, particles and the like generated at the periphery of the back surface of the semiconductor wafer and the contact portion of the wafer container move to the front surface side of the semiconductor wafer. The phenomenon of indentation occurs. Therefore, it is necessary to prevent any part of the wafer storage container from contacting the peripheral edge portion Z of the semiconductor wafer back surface (for example, 2 to 10 mm from the top edge of the wafer side excluding the side edge top portion 102 and the bevel lower portion 104). It is coming. (The size of the edge region Y is about 0.4 to 1.0 mm in the case of a 450 mm wafer having a wafer thickness of 0.8 to 1.0 mm.)

  The wafer storage container of the present invention, in order to accurately answer such a requirement, when the storage container body having at least one opening, a lid body that closes the opening, and when the storage container body is closed by the lid body In a wafer storage container having a seal that hermetically isolates the inside of the storage container body from an external environment, and a wafer support that is formed inside the storage container body and supports the wafer in alignment, the wafer support includes a plurality of A plurality of shelves that align and support wafers in an axial direction at predetermined intervals, a support plate portion that supports the shelf, and a support plate mounting portion for mounting the support plate portion inside the storage container body; And a restricting portion for restricting the plurality of wafers formed in the support plate portion in the radial direction, and further, one or a plurality of holes are formed inside the shelf. The “structure with holes inside the shelf” or “annular structure with holes” described in the present application has a structure in which the holes inside the shelf are completely surrounded by the shelf and the support plate, for example, the shelf and the support plate. Not only is the structure ring-shaped or frame-shaped, and the entire periphery is connected, but also a structure in which the hole inside the shelf is incompletely surrounded by the shelf and support plate, for example, A cut structure, for example, a structure in which a part or all of the support plate portion forming a ring shape or a frame shape is not included is also included. Examples of the former include B-shaped and D-shaped shelves, which will be described later, or substantially isosceles triangular shelves. Examples of the latter include a shelf having an E-shape as shown in FIG. 22 described later, or a shape without a D-shaped or B-shaped vertical bar. In addition, the shelf is formed on the upper surface of the shelf (on the side where the wafer is placed and on the side in contact with the back surface of the wafer), and one or a plurality of placements for supporting and placing the back surface of the wafer. Has a protrusion

  Examples of the wafer storage container of the present invention are shown in FIGS. FIG. 2 is a perspective view of the wafer storage container 1 in a state in which the lid body 4 is combined with the container body 2. FIG. 1 is a perspective view showing the inside of the wafer storage container 1 shown in FIG. A wafer support 3 provided on opposing side walls of the container main body 2 for storing a plurality of semiconductor wafers S and supporting only one side (the back surface of the semiconductor wafer S) of the semiconductor wafer S stored therein; It is comprised from the cover body 4 which plugs up the opening 2F. Further, a top flange 5 held by an arm portion of a transfer device (not shown) and a carrying handle 6 that is held when an operator carries the wafer support container 1 by hand are provided.

  1 and 2, the container body 2 is formed in a substantially cubic shape as a whole. The container body 2 is normally carried in a vertically placed state (a state in which the bottom plate portion 2E is down). However, when the semiconductor wafer S is taken in and out, the container body 2 is horizontally placed so that the surface of the semiconductor wafer is on the top. The container main body 2 is composed of four side wall portions 2A, 2B, 2C, 2D and a bottom plate portion 2E as peripheral walls, and an opening 2F is provided on the upper portion thereof. Each side wall 2A, 2B, 2C, 2D is provided with reinforcing ribs 9 and the like. When the container body 2 is installed facing a wafer transfer robot (not shown) in the production line of the semiconductor wafer S or the like, the container body 2 is accurately positioned on the mounting table and placed horizontally (state shown in FIG. 2). The A top flange 5 is detachably attached by an attachment / detachment mechanism 12 on the outer side of the side wall 2B that becomes a ceiling portion in a horizontally placed state. A carrying handle 6 is detachably attached by an attaching / detaching mechanism 12 on the outside of the side wall portions 2C, 2D which become the horizontal wall portion in the horizontal state.

  As shown in FIG. 1, a lid receiving step 47 for fitting the lid 4 is provided at the upper end of the container body 2. The lid receiving step 47 is formed by expanding the upper end of the container body 2 to the dimensions of the lid 4. Thus, the lid body 4 is fitted to the inside of the vertical plate portion 47A of the lid body receiving step portion 47, and is attached to the lid body receiving step portion 47 by contacting the horizontal plate portion 47B. . Further, a seal (not shown) attached to the lower surface of the lid 4 is brought into contact with the horizontal plate portion 47B so as to seal the inside of the wafer support container 1. A fitting hole 48 for fixing a dedicated lid (not shown) used in the semiconductor manufacturing process to the container body 2 side is provided inside the vertical plate portion 47A of the lid receiving step 47. Yes. The fitting holes 48 are provided at the four corners of the lid receiving step 47. The position and shape of the fitting hole 48 are appropriately set according to a dedicated lid used in the semiconductor manufacturing process.

  As shown in FIGS. 1 and 3, the wafer support 3 is a member that is provided on each of the opposing side wall portions 2 </ b> C and 2 </ b> D in the container body 2 and supports the semiconductor wafer S accommodated therein from both sides. . The wafer support 3 is detachably attached to the inside of the container main body 2 and is formed of a pair of opposing mirror image structures having a bilateral reference plane as a symmetry plane in the wafer storage container. (The bilateral reference plane is a reference plane that bisects the opening of the wafer container through the wafer center defined by the SEMI standard.) The wafer support 3 is mainly arranged at a certain interval in parallel. A plurality of shelves 50 that support each semiconductor wafer S spaced apart one by one, and these shelves 50 are integrally supported in a state where they are arranged in parallel at a constant interval (wafer support). It is comprised from the support plate part 51. FIG. Further, the support plate portion 51 has a restricting portion 201 (shown in FIGS. 4 to 9) for restricting the semiconductor wafer S in the radial direction of the wafer.

  As shown in FIG. 3, the shelf 50 has one large hole inside. That is, it is a bridge type that is supported by the support plate portion 51 at least at two locations (M and N) with an annular structure in which the inside is perforated. This can also be called a D-shaped shelf. The shelf 50 is supported by a support plate portion 51, and is composed of two arm portions 34 extending from the support plate portion 51 and a band-shaped portion 33 connecting the arm portions, and a portion 36 surrounded by these has a perforated state inside. It has an annular structure. That is, an annular structure (hereinafter referred to as “annular structure” or “annular structure”) in which the shelf is surrounded by the support plate portion 51, the two arm portions 34, and the belt-shaped portion 33 and the inside of the shelf is perforated is formed. ing. In FIG. 3, the support plate portion 51 is shown as an integrated object (one curved plate-like object). However, as shown in FIG. 13, the support plate portion is divided into support plates 35 that support the shelf 50. It is also possible to consist of (vertical) support plates 37 (two in FIG. 3) that support the support plate 35. Such a divided support plate has an advantage that the weight of the support plate can be reduced. In addition, since the width of the two support plates 37 can be adjusted, a sufficient space can be created between the two support plates 37. From the outside (if the wafer storage container is transparent, the wafer There is an advantage that the wafer setting state can be observed (from the outside of the storage container). In FIG. 13, the support plate 37 is supported on the support plate 35, but it may be sandwiched between the support plates 35, or they may be molded as an integral object.

  The shelf 50 is provided with a mounting protrusion 52 for supporting and mounting the back surface of the semiconductor wafer at a predetermined position. 4-8 is a figure for demonstrating the state of the shelf 50 of this invention which has various shapes, the support plate part 51, and a semiconductor wafer. The state in which the wafer support 3 is set on the opposite side wall 2C or 2D in the container body 2 is viewed from the side of the wafer support 3. Since the wafer support 3 is formed of a pair of opposing mirror image structures having a bilateral reference plane as a symmetry plane in the wafer storage container, only one side is shown in FIGS. (The bilateral reference plane coincides with the vertical center line (indicated by the alternate long and short dash line) passing through the wafer center in the figure. In FIG. 4, an example of a semicircular arc-shaped shelf is shown. FIG. (The shelf in FIG. 4 also has one large hole on the inside, and can be considered as a kind of D-shaped shelf.) The shelf 50 is attached to the support plate portion 51 of the wafer support 3, and the shelf 50. Is supported at two places (M and N in the figure) of the support plate portion 51. The shelf 50 has an arc-like band shape from M and N, and the inside (inside) 36 of the shelf 50 has an annular structure. Since the shelf 50 has an annular structure, the weight of the shelf 50 can be reduced, and the deflection due to the weight of the shelf 50 can be reduced.

  Further, since the shelf 50 is supported by the support plate portion 51 at two locations M and N, the shelf 50 is supported more firmly. Accordingly, since the shelf 50 can be extended in the radial direction of the semiconductor wafer, the degree of freedom for adjusting the position for supporting the back surface of the semiconductor wafer is also increased. Since a semiconductor wafer is placed on the shelf 50, in order to create a state in which the shelf 50 is not distorted, it is necessary to increase the support strength by the support plate portion in M and N or increase the strength of the shelf itself. In addition, since it is also effective to reduce the weight of the shelf itself, it is also effective to make the shelf 50 thinner and thinner as the distance from the support portions M and N is increased in addition to the annular structure. Further, by adopting an annular structure, the shelf can be extended toward the center of the wafer, the wafer back surface in a wider area can be supported, and the indicated position on the wafer back surface (that is, the position of the mounting protrusion 52). The degree of freedom can be increased.

  The shelf 50 is provided with mounting projections 52 at three locations (P, Q, and R in the figure), and supports the semiconductor wafer from the back surface side in contact with a predetermined portion of the back surface of the semiconductor wafer. The semiconductor wafer is regulated in the radial direction at the regulation part 201 (provided on the support plate part 51) of the wafer support 3 with the peripheral edge of the semiconductor wafer contacting the wafer support 3. When the wafer storage container is taken in or out, the wafer storage container 1 is arranged so that the back surface of the semiconductor wafer faces down (the mounting protrusion 52 of the shelf 50 faces upward). Then, the wafer is inserted into the wafer storage container main body 2 (for example, the back surface of the wafer is placed on the fork) and placed on the mounting protrusion 52 of the shelf 50. There is a pair of shelves 50 in the wafer storage container main body 2. That is, two places) (a plurality of placement protrusions 52 are also present on the shelf 50), so that the semiconductor wafer does not move even if the hawk is removed after the semiconductor wafer is placed on the placement protrusions 52. (Naturally, it is necessary to place the mounting protrusions 52 so that the semiconductor wafers are horizontal.) After the desired number of semiconductor wafers are placed in the wafer storage container, the lid 4 A wafer pressing member 94 (shown in FIG. 10) having a restricting portion that comes into contact with the peripheral edge of the wafer and restricts the wafer in the radial direction is also attached to the lid 4. The semiconductor wafer is pressed and fixed by the force in the radial direction of the semiconductor wafer from the regulating portion 201 of the pair of wafer supports 3 installed in the wafer storage container body and the wafer pressing member 94 attached to the lid 4.

  Here, the restriction part 201 of the wafer support 3 of the present invention will be described with reference to FIG. FIG. 9 is a view of the state in which the semiconductor wafer is installed on the wafer support as viewed from the thickness direction of the wafer. S is a semiconductor wafer, 50 is a shelf, 52 is a mounting protrusion, and 201 is a restricting portion. The restricting portion 201 is a region where the wafer edge portion contacts the support plate portion 51 of the wafer support 3 and restricts the wafer in the radial direction. In the drawing, the restricting portion and the shelf are shown to be in the same position, but the position where the wafer edge contacts the restricting portion may be different from the shelf position. Further, as can be seen from FIGS. 4 to 7, the restricting portion 201 is not necessarily continuous with the shelf 50. (It may be continuous. That is, a restricting portion may be provided in the L, M, and N portions.) The restricting portion 201 is desirably installed at an optimum position for fixing the semiconductor wafer. When it is desired to minimize the portion in contact with the semiconductor wafer, the portion in contact with the wafer may be reduced as much as possible. However, when the generation of particles or the like due to contact is very small, or when the generation of particles or the like due to contact is not a problem, it is possible to fix the wafer more strongly by increasing the area in contact with the wafer by the restriction unit 201.

  FIG. 9A shows a case where the restricting portion 201 has a V groove (or U groove). The edge of the semiconductor wafer S is sandwiched between the V grooves 202 of the restricting portion 201, and the back surface of the semiconductor wafer S is supported and fixed to the mounting protrusion 52 of the shelf 50. When such a V-groove or U-groove is used for the restricting portion 201, the bevel upper portion 103 of the semiconductor wafer edge portion Y is also in contact with the restricting portion 201. There is a problem that it easily adheres to the region.

FIG. 9B is a view showing the restricting portion 201 having a side wall in which the restricting portion 201 has a substantially right-angled wall shape. The tip of the edge of the semiconductor wafer S, that is, the side edge top portion 102 of the semiconductor wafer S is only in contact with the side wall 203 of the restricting portion 201 and is not in contact with the bevel upper portion 103 or the bevel lower portion 104 of the semiconductor wafer S. . The back surface of the semiconductor wafer S is supported by the mounting protrusion 52. In this case, since the upper part of the bevel of the semiconductor wafer edge portion is not in contact with the restricting portion 201, there is a problem that particles or the like generated from the contact portion easily adhere to the device region on the surface of the semiconductor wafer as shown in FIG. The point doesn't happen.
FIG. 9C is a diagram showing a case where the lower portion 204 of the restricting portion 201 (the portion that contacts the back side of the semiconductor wafer S) is inclined. Of the edge of the semiconductor wafer S, the lower bevel 104 comes into contact with the inclined surface 204. Further, by adjusting the height of the mounting protrusion 52, the inclined surface 204 of the restricting portion 201 comes into contact with the lower bevel 104 of the semiconductor wafer S and the side end top portion 102 of the semiconductor wafer S is perpendicular to the side wall 203 of the restricting portion 201. Can be touched. Since the contact area between the semiconductor wafer S and the restricting portion 201 is larger than in the case of FIG. 9B, the stability of the semiconductor wafer in the wafer storage container is increased. Also in this case, since the bevel upper portion 103 of the semiconductor wafer edge portion is not in contact with the restricting portion 201, the problem that particles generated from the contact portion adhere to the device region on the surface of the semiconductor wafer as in FIG. The point doesn't happen.

  In the present invention, the mounting protrusions (52 (P), 52 (Q), 52 (R)) are centered on the wafer center, and the opening side and the bottom side (opening side) from the facial reference surface of the storage container body. 0 ° to δ degrees (δ is in the range of 30 to 70) in the direction toward the back, that is, the lower side of the storage container or the back side facing the opening when the storage container is placed with the opening side up. Value). The facial reference plane is a vertical plane that bisects the wafer stored in the storage container body and is parallel to the front surface of the storage container (where the wafer is put in and out, that is, the opening surface). In FIG. 4, the facial reference plane is a plane that includes a center line G passing through the center of the wafer and is perpendicular to the paper surface. In FIG. 4, the mounting protrusion 52 (P) has an angle r1 from the facial reference plane G to the opening side (upper side in FIG. 4) with the wafer center O as the center, and the mounting protrusion 52 (R) An angle r2 is formed from the facial reference plane G toward the bottom side (downward in FIG. 4) with the center O as the center. r1 and r2 are in the range of 0 to δ degrees, and δ has a value of 30 to 70, so that the wafer can be stably placed. Furthermore, when r1 and r2 are substantially equal, the stability of the wafer is better. In addition, when the above range is exceeded, particularly when r1 exceeds 70 degrees, the shelf or the mounting projection may become an obstacle, and the end effector may not enter. In particular, when the pitch between the wafers to be placed is reduced, the obstacle increases. Since 52 (Q) is between 52 (P) and 52 (Q), the angle is smaller than r1 and r2. Even when there is one mounting protrusion or when there are many mounting protrusions, the position of the mounting protrusion is preferably in the range of 0 degrees to δ degrees (δ is a value of 30 to 70). is there.

  FIG. 4 shows the case where there is one mounting protrusion on each of the upper and lower sides and the vicinity of the reference surface with the facial reference plane as a boundary. However, the mounting protrusion on the shelf attached to another wafer support is shown. If the wafer can be stably placed on the shelf in consideration of the relationship, the placement protrusions may be arranged so as to be biased to either one. Similarly, when there are one or two mounting projections, they may be arranged so as to be biased up and down or near the reference plane with the facial reference plane as a boundary. Further, even in the case of four or more mounting protrusions, the mounting protrusions may be arranged on the top or bottom of the facial reference surface or on the vicinity of the reference surface, or may be distributed in these regions. May be. As described above, the mounting protrusion is preferably in the range of 0 to δ degrees (δ is a value of 30 to 70). However, there is no problem in loading / unloading of the wafer or the stability of the wafer is a problem. If not, a mounting projection may be provided at a position deviated from this angle. In particular, on the bottom side, when the shelf of one wafer support is connected to the shelf of the other wafer support, as shown in FIG.

  Although the back surface of the wafer at a substantially constant distance from the center of the wafer stored in the storage container can be considered as a contactable area (that is, the position of the mounting protrusion), it is easy to put the wafer in and out of the storage container and warp the wafer. From this point of view, this distance is 0.3 to 0.5 times the wafer diameter. Furthermore, since the fork and arm for taking in and out the wafer as described above are placed in the wafer storage container 1, the shelf 50 may not be disposed within a certain range from the center of the wafer storage container 1. That is, it is necessary to design the arrangement and size of the shelf 50 while avoiding the wafer handling zone. Since the semiconductor wafer is mounted on the mounting protrusion 52 in the shelf 50, it is necessary to calculate the overall balance and calculate the position of the mounting protrusion 52 in the shelf 50 so that the semiconductor wafer does not rotate or move. There is. For example, as shown in FIG. 4, when r1 and r2 are substantially equal, and the mounting protrusions 52 are installed at three positions where 52 (Q) is in the middle (that is, near the facial surface), a stable state is obtained. become. The mounting protrusion 52 can be made into a minute shape to reduce the contact area with the back surface of the semiconductor wafer to reduce the influence caused by the contact portion, or when it is made too small, the weight per unit area is increased. Therefore, the optimum shape can be calculated in consideration of the degree of wear. Further, the number of mounting protrusions 52 is not limited to the above-described three places, and can be increased. Alternatively (since the wafer supports are paired and a rear shelf, which will be described later, may be attached), one or two mounting protrusions 52 may be provided if the wafer is stable. From the above, it is possible to provide the mounting protrusion 52 at one or more places within the above angle within the range of 0 degrees to δ degrees (δ is a value in the range of 30 to 70).

  Furthermore, in order to satisfy the standards in the semiconductor industry, the shelf 50 is preferably formed at a position having a prospective angle r of 60 to 140 degrees around the center of the wafer at the back surface position of the semiconductor wafer. Yes (shown in FIG. 7). As can be seen from FIG. 7, the prospective angle described here is a central angle corresponding to the range occupied by the shelf in the circumferential direction of the wafer when the shelf is viewed from the center of the wafer. Therefore, if the shelf occupies the entire circumference, the expected angle is 360 degrees, and if the shelf occupies half of the circumference, the expected angle is 180 degrees. The rear surface of the wafer at a substantially constant distance from the bilateral surface can be considered as a contactable area. However, considering the ease of loading and unloading of the wafer from the container and the deflection of the wafer, this distance is 0.3 times the wafer diameter. The estimated angle r of the contactable region is about 140 degrees. Further, in order to stably place the wafer, it is preferable that the prospective angle r is about 60 degrees (when the shelf is one shelf with respect to the wafer support).

  Furthermore, since the fork and arm for taking in and out the wafer as described above are placed in the wafer storage container 1, the shelf 50 may not be disposed within a certain range from the center of the wafer storage container 1. That is, it is necessary to design the arrangement and size of the shelf 50 while avoiding the wafer handling zone. Since the semiconductor wafer is mounted on the mounting protrusion 52 in the shelf 50, it is necessary to calculate the overall balance and calculate the position of the mounting protrusion 52 in the shelf 50 so that the semiconductor wafer does not rotate or move. There is. For example, when the mounting projections 52 are installed at three positions, which are positions where the prospective angle is approximately divided into two, in the band-like portion 33 of the shelf 50 formed at the expected angle r, a stable state is obtained. The mounting protrusion 52 can be made into a minute shape to reduce the contact area with the back surface of the semiconductor wafer to reduce the influence caused by the contact portion, or when it is made too small, the weight per unit area is increased. Therefore, the optimum shape can be calculated in consideration of the degree of wear. Further, the number of mounting protrusions 52 is not limited to the above-described three places, and can be increased. Alternatively, one or two mounting protrusions 52 may be used if the wafer is stable. From the above, the mounting protrusions 52 can be provided at one or more places around the position where the prospective angle is approximately divided into two in the strip portion 33 of the shelf 50 formed at the expected angle r.

  The shelf 50 of the present invention can also be used when prohibiting the wafer storage container from contacting the periphery of the back surface of the semiconductor wafer. That is, in the arm portion 34 and the strip portion 33 of the shelf 50 (the arm portion and the strip portion coincide with each other because the shelf in FIG. 4 has an arc shape), the portion corresponding to the wafer peripheral portion (usually, It can be easily realized that the mounting protrusion 52 is not provided in the place of the arm portion 34).

  FIG. 5 is a diagram illustrating an example of another shelf 50. A shelf 50 is attached to the support plate portion 51 of the wafer support 3, and the shelf 50 is supported at two locations (M and N in the drawing) of the support plate portion 51. The shelf 50 extends from M and N, bends in the middle, and extends in a band shape in the circumferential direction of the semiconductor wafer. Of course, the inside of the shelf 50 has an annular structure. In FIG. 5, the placement protrusions 52 are provided in three places (P, Q, R) on the circumferential belt-like portion 33. In this state as well, the moment force of the semiconductor wafer can be balanced (the wafer mounting position is substantially equidistant from the wafer center), so that the semiconductor wafer sits well. A restricting portion 201 is also shown. Note that the shelf in FIG. 5 can also be considered as a D-shaped shelf in the sense that the arm portion and the belt-like portion surround one large hole inside the shelf.

  FIG. 6 is a diagram illustrating an example of another shelf 50. A shelf 50 is attached to the support plate portion 51 of the wafer support 3, and the shelf 50 is supported at two locations (M and N in the drawing) of the support plate portion 51. The shelf 50 has a rectangular band shape with an annular structure inside. In FIG. 6, the placement protrusions 52 are provided at three places (P, Q, R) on the belt-like portion 33 in the longitudinal direction. If the placement protrusion 52 is not stable when the wafer is placed at one place, two or more places, that is, a plurality of placement protrusions 52 are provided. (The same applies to FIGS. 5 and 6.) The shelf in FIG. 6 is also a kind of D-shaped shelf.

  FIG. 7 shows the case where the shelf 50 is supported at three places (L, M and N in the figure) of the support plate portion 51, and the arc-shaped shelf 50 whose shape is the same as FIG. FIG. The belt-like portion 33 is reinforced with the support portion 51 and the middle. In FIG. 7, the mounting protrusions 52 are provided at three places (P, Q, R) on the circumferential belt-like portion 33. Similarly, the shelf 50 having the shape shown in FIGS. 5 and 6 can be supported by the support plate portion 51 in the vicinity of the center, and the belt-like portion 33 can be reinforced. The shelf shown in FIG. 7 has two holes on the inside and can be called a B-shaped shelf.

  The shelf of the present invention can have more holes than a shelf with two holes on the inside, such as the B-shaped shelf shown in FIG. For example, an arm part or a belt-like part is formed as a frame in a mesh shape. Mounting protrusions are provided at one or a plurality of positions of the mesh frame portion so that the wafer can be mounted thereon. With such a structure, the weight of the wafer placed on the placing projection can be distributed over a number of frames. As described above, the shelf according to the present invention has one or a plurality of holes on the inside thereof, thereby reducing the weight of the shelf and reducing the force exerted on the base between the shelf and the support plate portion. It is possible to prevent the shelf from being bent excessively even when it is placed on the mounting protrusion of the shelf.

  FIG. 8 is a view showing a state in which the shelf 50 is connected to the shelves of the two wafer supports 3 provided in a pair with the opposing side wall portions 2C and 2D in the container main body 2. The shape of the wafer support 3 shown in FIG. 8 is similar to that shown in FIG. 5, but the strip-like portion 33 of the shelf 50 extends in the circumferential direction (downward), and the strip-like portion of the shelf 50 in the other wafer support 3. It is connected with. Such a continuous wafer support 3 can also be used in the present invention.

  As described above, the shelf 50 plays a role of supporting a plurality of wafers by aligning them in the axial direction (semiconductor wafer) at a predetermined interval. The thickness of the semiconductor wafer depends on the wafer size, but is about 0.4 mm to about 1.2 mm before the back surface grinding. Also, the shelf thickness is about 0.2 mm to about 2.0 mm (for wafers with a diameter of 100 mm to 600 mm). Considering the height of the mounting protrusion and the gap between the shelf and the wafer, the pitch between the shelves in the storage container is about 5 mm to 25 mm.

  As shown in FIG. 3, two handles 54 are provided on the upper portion of the wafer support 3. The handle 54 is a portion that is gripped when the wafer support 3 is lifted. The two handles 54 are picked and lifted with fingers or a machine. The support plate portion 51 integrally supports the shelves and the restricting portion. The wafer support 3 is detachably fixed to the opposing side wall portions 2C and 2D in the container body 2 by an upper fitting portion 55 and a lower fitting portion 56. The upper fitting portion 55 and the lower fitting portion 56 constitute an attachment portion for the wafer support 3.

FIG. 1 shows the wafer support 3 attached to the side wall 2D of the wafer storage container body. A method for fixing the wafer support 3 to the wafer storage container is described in detail in, for example, Japanese Patent Application Laid-Open No. 2004-214269. When the lid 4 that closes the opening 2F of the storage container body 2 is closed in accordance with the storage container body, the inside of the storage container body 2 is airtight from the external environment by a seal provided on the storage container body side and / or the lid body side. Isolated.

  FIG. 10 is a perspective view showing a wafer pressing member that holds the wafer in accordance with the lid, and FIG. 11 is a plan view thereof. As shown in FIGS. 10 and 11, the wafer pressing member 94 is formed in a substantially rectangular shape. Both end portions and the center portion of the wafer pressing member 94 in the longitudinal direction are fixed to the back surface of the lid body 4, and a pressing portion 95 is formed therebetween. The pressing portion 95 is a member for elastically pressing and supporting the semiconductor wafer S from above, and is constituted by a plurality of pressing bands 96 arranged in parallel. The holding band 96 is a member having elasticity, and is formed by bending downward. Further, the pressing band 96 is formed by curving its planar shape (the shape in the state of FIG. 11) into a waveform along the periphery of the semiconductor wafer S so that the semiconductor wafer S does not enter the gap of the pressing band 96. ing.

  The side surface shape of the pressing band 96 is formed in a mountain shape facing downward. At the two apex positions of the chevron, there are provided fitting grooves 97 for fitting the semiconductor wafers S one by one and supporting them at a predetermined interval. The fitting groove 97 is formed at an acute angle so as to sandwich the periphery of the semiconductor wafer S.

  The wafer pressing member 94 may be set in the storage container body after the wafer is set in the storage container body, and then the lid 4 may be closed in accordance with the storage container body 2. Alternatively, the wafer holding member 94 may be set in advance on the lid body 4 so as to be adapted to the wafer set in the storage container body 2 when the lid body 4 is aligned with the storage container body 2. The latter is more suitable for automation. The semiconductor wafer S fitted into the fitting groove 97 of the wafer pressing member 94 is sandwiched and supported by the fitting groove 97 formed at an acute angle. Although the fitting groove 97 can be formed at such an acute angle, in general, the fitting groove 97 is optimized so that the wafer is properly taken out and held. In other words, the fitting groove 97 does not necessarily have an acute angle, and may have a U shape so that it can be supported by an obtuse angle or a substantially vertical surface. As a result, even when a strong impact is applied to the wafer support container 1, the fitting groove 97 can sandwich the periphery of the semiconductor wafer S to suppress rotation and displacement and reliably support the wafer. In addition, since the press band 96 is formed in a waveform along the periphery of the semiconductor wafer S, even if the semiconductor wafer S is detached from the fitting groove 97, it does not enter between the press bands 96.

  The fitting groove 97 may be formed in a V groove (or U groove) as shown in FIG. At this time, an effect similar to that obtained when the fitting groove 97 is made an acute angle is obtained. Alternatively, as shown in FIG. 9B or FIG. 9C, the structure is such that only the side edge top portion of the semiconductor wafer, or only the side edge top portion of the semiconductor wafer and the lower portion of the wafer bevel contacts the wafer. May be. At this time, there is no effect of sandwiching the wafer, but the semiconductor wafer is moved by the restricting portion (a pair) of the wafer support 3 and the wafer pressing member 94 by the force of pushing the side edge of the semiconductor wafer in the radial direction of the semiconductor wafer. Fixed.

  The wafer pressing member 94 may have a shelf and mounting protrusion similar to those shown in FIG. 9 and support the back surface of the semiconductor wafer. By providing such a shelf, the semiconductor wafer can be fixed more stably.

  If the wafer becomes larger than 300 mm and the diameter is increased, the amount of bending increases if the thickness of the wafer is kept as it is. Therefore, it is necessary to increase the wafer thickness in order to suppress the amount of bending, and the wafer is proportional to the increase in the volume of the wafer. The weight also increases. Therefore, when the shelf of the present invention is horizontal, when the wafer is increased in diameter, the shelf is bent downward when the wafer is placed depending on the strength of the shelf. When this deflection increases, the wafer peripheral surface supported by the mounting protrusion comes into contact with the shelf, and particles are generated by the contact. In order to prevent this, in the present invention, the wafer center axis further extends from the root of the shelf to the (wafer support) support plate portion toward the tip of the shelf, that is, the wafer center in the radial direction of the wafer to be placed. Inclined in the upper side direction, that is, from the back side of the wafer to be placed to the front side. Then, the uppermost part of the shelf is made to be the uppermost part of the mounting protrusion formed on the shelf.

  FIG. 14 is a view schematically showing such an inclined shelf. FIG. 14 is a view seen from the wafer loading direction, that is, the wafer radial direction with the lid of the wafer storage container removed (the side wall portion 2A in FIG. 1). In the state where The bottom of the figure is the wafer back side, and the top of the figure is the wafer front side. (Wafer support) support plate portions 312 are attached to both side wall portions (left and right side wall portions, 2C and 2D in FIGS. 1 and 2) of the storage container main body 311. As shown in FIG. 14, the (wafer support) support plate portion 312 is substantially perpendicular to the side wall portions (2C, 2D) of the storage container body 311 at three attachment portions (upper portion 315, center 316, lower portion 317). Is attached. Further, the (wafer support) support plate portion 312 is attached substantially symmetrically to both side wall portions (2C, 2D) of the storage container main body 311. The shelf 313 is tilted upward with respect to the (wafer support) support plate portion 312 (wafer support) and attached to the support plate portion 312. The number of shelves 313 arranged in the axial direction of the wafer is the same as the number of wafers stored in the wafer storage container, the inclination angle is constant (θ), and the pitch of the shelves 313 is also constant. The inclination angle may be considered as an angle formed between the central axis of the inclined shelf and the wafer back surface, or an angle formed between the wafer back surface supported by the inclined shelf and the surface of the shelf facing the wafer back surface. You may think. A mounting projection 319 is attached to the tip of the shelf 313, and the uppermost portion of the mounting projection 319 is the highest in the shelf 313. As shown in FIG. 14, the back surface of the wafer S is placed on the shelf and stored in a wafer storage container. As described above, the peripheral portion of the wafer S is in contact with the restricting portion 314 that restricts the wafer S in the radial direction, and this contact state is the same as that described with reference to FIG.

  The back surface of the wafer S is in contact with the highest portion of the shelf 313, that is, the mounting protrusion 319. If the wafer S is supported only at the peripheral edge and the back surface of the wafer S is free (not supported), the wafer S bends due to its weight. However, as described above, when the wafer S is enlarged, the bend is caused. The amount also increases. If the wafer S is placed on the shelf of the present invention, since the wafer S is supported also from the back surface, bending of the wafer is also suppressed. However, in the case of a horizontal shelf, the shelf may sink downward due to the weight of the wafer S. In particular, when the shelf is thin or the shelf is made of a material with low strength, the amount of deformation downward increases, so that the wafers S contact each other or the shelf contacts the wafer surface. There is a risk. Further, the storage container becomes large due to the necessity of taking a sufficient pitch of the shelf in order to prevent such contact. Furthermore, there is a possibility that the back surface of the wafer contacts the vicinity of the root of the shelf due to the downward deformation of the shelf.

  Therefore, since the downward inclination can be suppressed by using an upwardly inclined shelf 319 as shown in FIG. 14, the pitch of the shelf can be reduced, the size of the wafer storage container can be reduced, or a larger number of wafers can be obtained. Can be stored in the wafer storage container. In addition, since the back surface of the wafer S does not come into contact with the portion of the shelf 313 other than the mounting protrusion 319, the thin film that wraps around the wafer back surface from the wafer surface is peeled off to become particles and contaminate the wafer. Therefore, the inside of the wafer storage container can be kept extremely clean. Furthermore, since the shelf can be thinned or narrowed, the shelf can be reduced in weight.

  In FIG. 14, only one mounting protrusion 319 is shown, but a plurality of mounting protrusions 319 may be used as long as the height of the mounting protrusion 319 can be made uniform. In the case of a plurality of mounting protrusions 319, the shelf is inclined, so the heights of the uppermost portions of the mounting protrusions 319 need to be matched and contacted to the back surface of the wafer equally. Since the back surface of the wafer is placed on the mounting protrusions 319, if the height of the uppermost portion of the mounting protrusion 319 varies, the wafer may be inclined or there may be a mounting protrusion 319 that does not contact the back surface of the wafer. Is not preferable. In the case where the mounting protrusions 319 are provided at a plurality of places where the height of the shelf 319 is equal, the mounting protrusions 319 having the same size (the height of a single mounting protrusion is equal) may be used. In the case where the mounting protrusions 319 are provided at a plurality of locations where the height of the shelf 319 is different, the mounting protrusions 319 have the same height at the top of the shelf when completed (or when attached to the wafer storage container). It is necessary to adjust the size (height of a single mounting projection).

  Even when the shelf is tilted, the views as seen from above the central axis of the wafer, that is, from above the wafer surface, are the same as those shown in FIGS. When the shape of the shelf is arcuate as shown in FIG. 4, the vicinity of the center of the arcuate shelf is the highest in the shelf. When only one mounting protrusion (52 (Q) in FIG. 4) is provided only in this portion, only the height of the mounting protrusion needs to be considered, but the mounting protrusion (FIG. 4) is also considered in other portions. 52 (P) and 52 (R)) are provided, the height of the (single) mounting protrusions of 52 (P) and 52 (R) is increased to be equal to the height of 52 (Q). There is a need.

  In the case of the shape as shown in FIG. Naturally, the arm portion 34 of the shelf is inclined upward, but the height of the entire belt-like portion 33 of the shelf can be made equal, or the belt-like portion 33 can be further inclined upward or downward. In order to make the belt-like portions 33 equal, it is only necessary to provide the placement protrusions 52 (P), 52 (Q), and 52 (R) having the same height. In the case of tilting, it is necessary to adjust the heights of the single mounting protrusions 52 (P), 52 (Q), and 52 (R) so that all of them have the same height.

  Even in the case of the shape as shown in FIG. Naturally, the arm portion 34 of the shelf is inclined upward, but the height of the entire belt-like portion 33 of the shelf can be made equal, or the belt-like portion 33 can be further inclined upward or downward. In order to make the belt-like portions 33 equal, it is only necessary to provide the placement protrusions 52 (P), 52 (Q), and 52 (R) having the same height. In the case of tilting, it is necessary to adjust the heights of the single mounting protrusions 52 (P), 52 (Q), and 52 (R) so that all of them have the same height.

  The shape shown in FIG. 7 is similar to the case shown in FIG. The arc-shaped portions 34 and 33 are inclined upward, but the reinforcing portion is also inclined upward. Near the center of the arcuate shelf is the highest of the shelves. When only one mounting protrusion (52 (Q) in FIG. 7) is provided only in this portion, only the height of this mounting protrusion needs to be considered, but the mounting protrusion (FIG. 7) is also considered in other portions. 52 (P) and 52 (R)) are provided, the height of the (single) mounting protrusions of 52 (P) and 52 (R) is increased to be equal to the height of 52 (Q). There is a need.

  In the case of the shape as shown in FIG. Naturally, the arm portion 34 of the shelf is inclined upward, but the height of the entire belt-like portion 33 of the shelf can be made equal, or the belt-like portion 33 can be further inclined upward or downward. In order to make the belt-like portions 33 equal, it is only necessary to provide the placement protrusions 52 (P), 52 (Q), and 52 (R) having the same height. In the case of tilting, it is necessary to adjust the heights of the single mounting protrusions 52 (P), 52 (Q), and 52 (R) so that all of them have the same height. Further, the portion connected to the shelf on the other side can have the same height, or can be inclined further upward or downward. In the case where the mounting protrusion is provided at the connecting portion, it is necessary to align the height with other mounting protrusions ((P), 52 (Q), and 52 (R)).

  FIG. 15 is a view showing an example of a shelf having another shape different from those shown in FIGS. 4 to 8, in a state in which the wafer storage container main body 331 is normally installed, that is, at the bottom (2E in FIG. ) Is the lower side, and the side (opening side) (2F in FIG. 1) is the upper side, and is a cross-sectional view in the direction in which the wafer surface can be seen in the front. (The wafer surface is not shown.) The wafer support shown in FIG. 15 is symmetrically attached to the opposing side wall portions 2C and 2D in the container main body 331, similarly to those shown in FIGS. The shelf formed on the wafer support also has an annular structure, but a plurality of shelves are formed adjacent to one side (wafer support) support plate portion 332 or 333. Thereby, weight reduction and strength improvement of a shelf can be achieved.

  The shelf shown in FIG. 15 has a substantially isosceles triangle shape whose bottom is located on the storage container main body side (side wall 2C side or 2D side) (or the bottom side is a substantially arc along the outer periphery of the wafer, and has two sub shelves. (This shelf is referred to as a “subshelf” in the sense of being distinguished from the shelf arranged in the axial direction of the wafer stored in the storage container described above.) The shape in which the wafers intersect at the front end on the same side) Two sub shelves 334 having substantially the same size and the same shape and having the same size (two sub shelves 334-1 and 334-2). It is formed on the wafer support. In addition, two similar sub-shelf 335 (335-1, 335-2) are formed on the wafer support attached to the opposite side wall portions almost symmetrically. The direction of the tip portion (also referred to as a vertex (portion)) where two equal-side sub-shelf intersects in one set of sub-shelf is substantially directed to the wafer center. In the case of such a cantilever type subshelf, the isosceles triangle shape is one of the strongest shapes when compared with the same material and the same weight, so it is optimal for the wafer support of the present invention. Shape. In addition, since it has a plurality of similar isosceles triangle shapes, even if a large-diameter wafer is supported, the bending is small and the twist is minimized. In FIG. 15, since there are two wafer supports, the wafer is supported by four isosceles triangular sub shelves. In general, the maximum number of sub shelves is determined by the angle (vertical angle), the equilateral length, and the (wafer support) support plate portion size at which the tips of one isosceles triangle intersect.

  The mounting protrusions 336 (336-1, 336-2) and 337 (337-1, 337-2) shown in FIG. 15 are formed in the vicinity of the apex facing the bottom of the isosceles triangular subshelf. That is, a first placement protrusion 336-1 is provided near the apex of the first subshelf 334-1, and a second placement protrusion 336-2 is provided near the apex of the second subshelf 334-2. In addition, a first placement protrusion 337-1 is provided near the vertex of the subshelf 335-1 at a symmetrical position, and a second placement protrusion 337-2 is provided near the vertex of the subshelf 335-2. Since the four isosceles triangles shown in FIG. 15 have the same size, the positions of the mounting protrusions formed at the vertices are located at approximately the same distance from the peripheral edge of the wafer mounted thereon. Support the back side. Accordingly, since the weight of the wafer is distributed to the mounting projections to the same extent, the deflection due to the weight of the wafer becomes more uniform. When the shelf (sub-shelf is the same) is horizontal, as described above, the shelf also deforms downward depending on the strength of the shelf and the weight of the wafer, but the isosceles triangle shape shown in the figure is the shape that minimizes deformation. It is one of. In order to further reduce the amount of deformation, the shelf is inclined upward with respect to the wafer surface as shown in FIG. That is, the shelf is formed so as to incline upward from the base portion of the shelf and the (wafer support) support plate portion toward the front end portion of the shelf toward the wafer center (axis) side. Thus, by making the shelf into a plurality of substantially isosceles triangle shapes and inclining the shelf, the deformation of the shelf can be suppressed and the wafer can be supported by only the mounting projections. As a result, the deflection of the wafer itself can be greatly reduced.

  Since the shelf and the mounting projection are usually resin-molded, a mold according to the shape of the shelf and the mounting projection is prepared by pouring resin into the mold (for example, injection molding).

  FIG. 19 is an enlarged schematic view of the wafer support (support plate portion and shelf) shown in FIG. The shelf 513 is inclined at the aforementioned angle θ with respect to the (wafer support) support plate portion 511. As described above, the (wafer support) support plate 511 is in a state perpendicular to the horizontal plane (or the wafer surface) when the wafer is placed in a state of being set in the storage container. This is the angle formed with the vertical direction relative to the horizontal plane. A mounting protrusion 514 is attached to the tip of the shelf 513, and the back surface of the wafer S comes into contact with the mounting protrusion 514, and the wafer S is mounted thereon. The angle θ is an angle formed between the back surface of the wafer supported by the shelf 513 and the surface of the shelf 513 facing the back surface of the wafer. If the angle between the shelf 513 and the horizontal is α, α = 90 ° −θ. Further, as described above, the edge portion of the wafer S is in contact with the restriction portion 512 of the (wafer support) support plate portion 511. The angle α may be 0.1 ° or more. However, when the shelf 513 is deformed downward due to the weight of the wafer when the wafer S is placed and the shelf is below the horizontal position, the angle α is 0.1 °. Make it bigger. If the angle α is increased, the interval (pitch) between the shelves 513 is naturally increased. Further, the pitch varies depending on the length of the shelf 513. Although it is desired to store a large number of wafers in the wafer storage container, the size of the wafer storage container is also limited, so the angle α is preferably 0.1 to 3.5 degrees. Since the (wafer support) support plate portion may be curved, the angle θ is considered to be the angle between the vertical direction with respect to the wafer surface (or horizontal plane) and the shelf when the wafer is placed on the shelf. May be good.

  The pitch of the shelf 513 is a, the distance from the restriction portion 512 of the (wafer support) support plate portion 511 to the contact position of the wafer that is the uppermost portion of the mounting projection 514, that is, from the root of the (wafer support) support plate portion 511. The wafer radial direction component of the length of the line segment connecting the uppermost part of the mounting protrusion 514 formed on the shelf 513 is b, the thickness of the base of the shelf 513 is c, and the uppermost end of the mounting protrusion 514 is from the upper end of the shelf 513. If the distance to the upper end is d and the distance from the uppermost end of the mounting protrusion 514 to the bottom end of the shelf 513 is e, a = c + d + e. Further, if the length of the shelf 513 (the distance from the root of the shelf 513 to the position of the shelf with the uppermost end of the mounting protrusion 514) is m, b = msinθ.

  b may be located inside the wafer peripheral edge (1-5 mm from the edge of the wafer), but when the wafer is enlarged, the wafer itself is bent by the weight of the wafer, so it is too short. Is not preferred. (The part inside the wafer from b is bent.) When the wafer diameter is 300 mm to 500 mm, b is preferably 40 to 100 mm. With such a shelf having b and α, there is no problem in loading and unloading the wafer, and the wafer back surface support can be performed by minimizing the deflection of the wafer due to the weight of the wafer. For example, it is possible to support the back surface of the wafer by minimizing the wafer deflection that occurs when a 450 mm wafer is placed, and at the same time, the wafer is supported without touching the resin burr generated on the shelf or the like when the shelf is molded. Became possible.

  When c = about 2.5 mm and e = about 2 mm, b = about 90 mm and α = about 3.5 degrees, the pitch a between shelves is about 10 mm. Note that c and α can be further reduced depending on the material strength of the shelf, and e increases and decreases depending on the thickness of the wafer and the allowance for loading and unloading the wafer into and from the storage container. Further, b varies depending on the degree of deformation due to the weight of the shelf itself and the degree of difficulty during loading and unloading of the wafer. For example, if the degree of deformation due to the weight of the shelf itself is not a problem and the difficulty at the time of loading and unloading is small, in the case of a large-diameter wafer, it may extend further to the inner side than 90 mm, that is, to the center of the wafer. The deflection of the wafer itself can be further reduced by providing one or more mounting protrusions in the meantime.

  When the subshelf shown in FIG. 15 is a substantially isosceles triangle, the apex angle is 15 to 140 degrees. It is preferably 45 to 75 degrees, and most preferably about 60 degrees. For example, in a 300 mm storage container, a sub shelf attached to one wafer support (assuming that the prospective angle of the wafer support portion region from the wafer center is about 75 degrees) is as follows. When b = 40 mm and the apex angle is 15 degrees, the base length of the approximately isosceles triangle is approximately 11 mm and the isosceles length is approximately 41 mm, so that approximately 18 isosceles triangle sub-shelves can be attached. When b = 40 mm and the apex angle is 45 degrees, the base length of the approximately isosceles triangle is approximately 34 mm and the isosceles length is approximately 44 mm. Therefore, up to approximately 6 isosceles triangle sub shelves can be attached. Up to about 4 at b = 40 mm and apex angle 60 degrees, up to about 3 at b = 40 mm and apex angle 75 degrees, and one approximately isosceles triangular subshelf at b = 40 mm and apex angle 140 degrees.

  In a 300 mm storage container, a sub shelf attached to one wafer support (assuming that the prospective angle of the wafer support portion region from the wafer center is about 75 degrees) is as follows at b = 90 mm. At an apex angle of 15 degrees, up to about eight isosceles triangle sub-shelf can be attached. At an apex angle of 45 degrees, up to two approximately isosceles triangular sub-shelf can be attached. At an apex angle of 60 degrees, about two approximately isosceles triangular sub shelves can be attached. With an apex angle of 75 degrees, you can attach a single isosceles triangle shelf.

  In a 450 mm storage container, a subshelf attached to one wafer support (assuming that the prospective angle of the wafer support portion region from the wafer center is about 75 degrees) is as follows when b = 90 mm. With an apex angle of 15 degrees, up to about 12 isosceles triangle sub-shelf can be attached. At an apex angle of 45 degrees, up to about 4 isosceles triangle sub-shelf can be attached. At an apex angle of 60 degrees, two substantially isosceles triangular sub-shelf can be attached. When the apex angle is 75 degrees, about two approximately isosceles triangular sub shelves can be attached.

  FIG. 16 is another embodiment having a tilted shelf of the present invention. The shelf 343 shown in FIG. 16 is inclined with respect to the (wafer support) support plate as in the shelf shown in FIG. 14, that is, with respect to the horizontal plane (or wafer surface) when the wafer is placed as described above. However, a shelf reinforcing rib 350 is further provided. The shelf reinforcing rib is formed between the surface of the shelf facing the wafer supported by the shelf and the (wafer support) support plate portion, and extends from the base of the shelf to the middle of the shelf to reinforce the shelf. Yes. The shelf reinforcing rib 350 makes it possible to minimize the deflection of the shelf due to the weight of the wafer when the wafer is placed, and to prevent the pitch of the shelves from becoming large. The number of stored sheets can be increased.

Also in FIG. 19, the shelf reinforcing rib 515 is shown. The shelf reinforcing rib 515 is thick at the base of the (wafer support) support plate portion 511 and the shelf 513 and extends horizontally in the wafer radial direction to reinforce the shelf 513. The most force is applied to this root. That is, in addition to the weight of the entire shelf, when the wafer is placed on the shelf, the weight of the wafer also increases. Therefore, the rib height of the base portion is increased in the height direction. Since the weight of the shelf reinforcing rib on the shelf also depends on the base part, it gradually becomes thinner in the height direction as it goes away from the base part so that there is no stress concentration part. In other words, the shelf reinforcing rib is attached from the base of the shelf to the middle of the shelf with the support plate portion, and the dimension of the shelf reinforcing rib in the wafer axial direction is large at the base and gradually decreases as the middle of the shelf is reached. Further, instead of such a shelf reinforcing rib, it is also effective to reinforce the shelf by forming the shelf so that the thickness of the shelf is increased at the base and becomes thinner toward the tip of the shelf. Note that the above-described reinforcement of the shelf can be applied not only to an inclined shelf but also to a horizontal shelf that is not inclined. For example, when the wafer is set on the mounting protrusion, the shelf is reinforced by partially thickening the shelf so that the front and back surfaces of the wafer do not contact the shelf, or by using different materials together. Just do it.

  FIG. 17 is a cross-sectional view showing shelf reinforcing ribs in a plurality of sub-shelf having a substantially isosceles triangle shape similar to FIG. 15 and viewed from the wafer surface side. Two isosceles (362-1 and 362-2, 363-1 and 363-2, 365-1 and 365-2, 365-2 and 366-1 and 366) in each of the sub-shelf 362, 363, 365, and 366 having a substantially isosceles triangle shape. -2), the shelf reinforcing ribs 371 (371-1, 371-2), 372 (372-1, 372-1) from the base of the sub shelf and the (wafer support) support plate (361, 364) to the middle of each equal side. 372-2), 373 (373-1, 373-2), 374 (374-1, 374-2). In addition, mounting protrusions 367, 368, 369, and 370 are attached to the top corners of the sub shelves 362, 363, 365, and 366, respectively, and the uppermost portions of these four mounting protrusions 367, 368, 369, and 370 are provided. The heights are equal, and when the wafer S is placed, the wafer S does not tilt because it is in contact with the back surface of the wafer S equally to these four mounting projections.

  FIG. 20 is a perspective view showing a state in which a wafer is placed on the same shelf (subshelf) as shown in FIG. The shelf 522 is inclined with respect to the (wafer support) support plate portion 521 and has two isosceles sides (522-1 and 522) having a substantially isosceles triangle shape with the (wafer support) support plate portion 521 side as a base. -2). A placement protrusion 523 is provided near the apex angle of the portion where two equal sides intersect, and the back surface of the wafer S is placed in contact with the placement protrusion 523. Shelf reinforcing ribs 524 (524-1, 524-2) are provided near the center of two equal sides from the base of the shelf 522. Since the wafer S is placed on the shelf 522, the shelf 522 receives a downward force due to the weight of the wafer S. The shelf 522 is cantilevered, and the weight of the wafer S and the weight of the shelf 522 itself are applied to the base of the (wafer support) support plate 521 and the shelf 522. Therefore, if the strength of the base portion is not sufficient, the shelf 522 may be deformed near the base portion. Since the shelf reinforcing rib 524 is also attached to the (wafer support) support plate portion 521, the shelf reinforcing rib 524 reinforces the shelf 522 at the base portion and suppresses deformation of the base portion. Further, the shelf 522 itself may be deformed downward, but the deformation is suppressed as much as possible by the shelf reinforcing rib 524. In particular, since the base portion of the shelf reinforcing rib 524 is thick and is gradually thinned toward the tip, this reinforcing degree is further strengthened.

  Note that the two equal sides (522-1 and 5222-2) of the shelf 522 are substantially equal, and the mounting projection 523 is also present at the apex corner, so that the downward force is equally applied to each equal side, and only one of them. Is designed not to receive extra power. This also reduces the deformation of the shelf as much as possible. As described above, the wafer S is in contact with the restriction portion 525 of the (wafer support) support plate portion, but the (wafer support) support plate portion 521 at the base of the shelf 522 is not necessarily in contact with the wafer S. Do not mean. That is, the wafer S has a circular shape, but the (wafer support) support plate portion does not necessarily have a circular shape. However, a part (or all) of the (wafer support) support plate portion on the shelf bottom side is in contact with the wafer edge, and this contact portion serves as a restricting portion that restricts the wafer in the radial direction. When the wafer edge is in contact with the whole (wafer support) support plate portion on the shelf bottom side, the restricting portion (that is, the portion in contact with the wafer edge of the (wafer support) support plate portion) is an arc shape that is substantially equal to the wafer diameter. It becomes.

18 shows a wafer support having a substantially isosceles triangular subshelf having shelf reinforcing ribs shown in FIG. 17, and an inner surface of the back surface (bottom plate 2E shown in FIG. 1) facing the opening of the storage container body. FIG. 6 shows another embodiment of the present invention in which a wafer support having a rear shelf (referred to as a “rear shelf” in the sense of a shelf provided on the back surface) is provided. The rear shelf 396 (two equal sides 396-1 and 396-2) has a rear (wafer support) support plate portion 395 corresponding to the bottom side and a substantially isosceles triangular ring structure. A rear wafer support is attached by a rear wafer support attachment portion 398 on the inner side of the back surface facing the opening of the storage container body. The rear shelf 396 is attached to the rear (wafer support) support plate portion 395, and the apex portion thereof is directed to the wafer center side in the same manner as the above-described shelf (subshelf) attached to the storage container side wall portion. A mounting projection 397 is provided at the apex portion of the substantially isosceles triangular rear shelf 396. When the storage container is placed horizontally, the height of the mounting protrusion 397 is set so that the mounting protrusions (387, 388, 389) in the other sub shelves (382, 383, 385, 386) attached to the side wall of the storage container. 390), and when the wafer S is mounted, the back surface of the wafer comes into contact with the mounting protrusion 397 like the other mounting protrusions.

  Therefore, the rear shelf 396 is inclined at an angle θ as much as the other shelves. (Alternatively, the height of the mounting protrusion 397 may be used.) When the other sub-shelf is not inclined, the rear shelf 396 is not inclined as well. In this way, by providing the rear shelf, the back surface of the wafer is supported not only in the sub shelves provided on the two storage container side walls facing each other, but also in a location at a substantially intermediate position between them. Wafer deflection can be further reduced, a narrower pitch can be realized, and the number of wafers stored in the storage container can be further increased.

  Similarly to other shelves (sub-shelf), shelf reinforcing ribs 399 (399-1 and 399-2) may be attached to reinforce the rear shelf 396. Note that the (rear) (wafer support) support plate portion 395 does not necessarily have to be a straight line as a base portion of an approximately isosceles triangle shape, and may be a curved shape. Further, the rear (wafer support) support plate portion 395 does not necessarily have a restriction portion, and the wafer edge may not be in contact with the rear (wafer support) support plate portion. (Wafer edge is in contact with another wafer support restricting portion.) However, the wafer can be more firmly fixed by providing a restricting portion on the rear (wafer support) support plate portion 395 and pressing it with the wafer edge.

  It should be noted that the wafer can be stably fixed to the storage container by setting the mounting protrusion at a constant distance from the center of the wafer stored in the storage container. This distance should be within the range of 0.3 to 0.5 times the diameter of the wafer to be accommodated so that the wafer can be easily taken in and out of the opening of the storage container and the deflection of the wafer is minimized. It is desirable to form.

  Until now, the wafer support has been mainly described as a member that can be separated or separated from the storage container. Since the wafer support has a complicated structure as described above, it is better that the wafer support can be divided or separated as described above in consideration of production of a mold and periodic cleaning. It is also possible to manufacture (for example, insert molding) as a single unit with the storage container from the structure. In the case of a one-piece product, there is an advantage that it is not necessary to attach and assemble the wafer support, and the storage container body and the wafer support can be manufactured by one molding. Also, with regard to cleaning, the same level of work as when cleaning separately can be completed by improving the cleaning device and cleaning liquid. For example, the mounting portion that is a component of the wafer support may be integrated with the storage container main body. A shelf (including a sub shelf) may also be formed as an integral part of the storage container body. Further, the restricting portion can be formed as an integral part of the storage container body. These can be formed together with the container body at the time of molding, for example, by insert molding.

FIG. 21 is a schematic diagram showing the shape of a wafer support ((wafer support) support plate and shelf) formed by insert molding. In the insert molding, a molded body of a wafer support is formed in advance, the molded body is inserted into a molding die of the storage container body, and then a resin is poured to form an integral body. (Wafer support) The support plate portion 602 is insert-molded by being disposed in a fitting portion formed in the storage container main body 601. The fitting portion refers to a portion where the wafer support is fused and integrally joined to the storage container body. Since the surface of the joining portion (the boundary portion between the storage container main body 601 and the (wafer support) support plate 602) is somewhat melted and fused, the joining becomes stronger, so that the wafer support to be inserted (especially the (wafer support) support) The plate portion 602) is preferably made of a material having a lower melting point than that of the storage container body 601 through which the resin flows later. However, if it is formed so as to wrap around the insert portion of the wafer support, this condition does not necessarily have to be satisfied. For example, as shown in FIG. 21, the wafer support and the container main body 601 are used so as to have the wrapping portion 606, or the wafer support and the container main body 601 are used so as to form the undercut 607. To do. As a result, the wafer support with the shelf 603 does not come off from the storage container body 601, and the (wafer support) support plate 602 and the storage container body 601 are firmly coupled. Of course, in combination with the fusibility, the bond is further strengthened.

  Further, by forming the corner portion of the insert portion in the wafer support as smoothly as possible, it is not necessary to concentrate stress on the resin of the storage container body to be flowed later, so that processing with high processing accuracy is possible. It may be better to avoid resins with extremely different thermal expansion coefficients. In such a case, if the temperature is applied to the molded product, the resin may expand and contract, which may cause the joint to peel off or cracks. In order to prevent such peeling due to heat shrinkage, it is desirable to partially form an undercut 607 as shown in FIG. Further, the thickness of the resin of the storage container main body 601 on the side surrounding the support plate portion 602 at the time of insertion (wafer support) needs to be sufficiently thick to withstand the internal stress generated by the insert. For example, it is important to design the thickness of the heel portion and the enveloping portion 606 that are outside the undercut 607.

  The shelf may not be integrated with the (wafer support) support plate, but only a complicated shelf may be divided and separated, and the shelf may be attached to the storage container when necessary.

  FIG. 22 shows another embodiment of the wafer support of the present invention. The feature of the wafer support 610 in this embodiment is that the inside of the (wafer support) support plate portion 611 is hollow (perforated state). A wafer support having such a hollow support plate portion can realize further weight reduction in addition to a perforated shelf. In FIG. 22, the middle support plate portion 611 is a restricting portion 612, and the wafer edge contacts this portion. The shelf 616 has an E shape with an inner hole. (The support plate portion side is vacant.) In the E-shaped shelf, a mounting protrusion 614 is disposed in the vicinity of the intersection of the straight portions (intersection of the arm portion 615 and the belt-like portion 613). In FIG. 22, there are three placement protrusions in one shelf. However, the number is not limited to three as described above, but may be one, two, or more than three. However, when the wafer is placed in the position as shown in FIG. 22, the total weight of the weight of the wafer and the weight of the shelf is equally distributed to the three arm portions 615. The shelf life is good and the shelf life can be extended. Even when the shelf does not have a D-shaped or B-shaped vertical bar, a hollow support plate similar to the wafer support shown in FIG. 22 can be used. It should be noted that the shelf in the case of such an E shape and the case where there is no B-shaped or D-shaped vertical bar is not limited to a horizontal one but can be naturally inclined as described above. It is. Further, as described above, these wafer supports can be formed by insert molding.

  So far, it has been described that one or a plurality of mounting projections are arranged at a predetermined position of the shelf, but a larger number of mounting projections can be arranged than in the case described in these embodiments. The mounting protrusion is a portion on which a wafer formed in a protruding (convex) shape or a protruding shape can be mounted. The tip of the mounting protrusion is fine and thin, and the portion that contacts the wafer back surface may be small. Alternatively, the mounting protrusion may be a mounting protrusion whose tip (where the wafer is mounted) is flat or curved. Alternatively, the mounting protrusion may be formed at a predetermined position on the upper surface of the shelf (on the side where the wafer is mounted and on the side in contact with the wafer back surface) so as to support the back surface of the wafer. The place on which the wafer is placed may be a placement protrusion in which the whole shelf or a part of the shelf that overlaps the wafer in plan contact with the back surface of the wafer. In this case, the shelf itself supports the back surface of the wafer. Even in this case, the portion of the shelf corresponding to the place where the wafer is not desired to be supported on the back surface of the wafer can be made concave so as not to contact the back surface of the wafer. For example, if it is not desired to bring the peripheral portion of the wafer back surface into contact with the shelf, the portion of the shelf that receives the peripheral portion of the wafer back surface may be recessed or eliminated. Alternatively, the shape of the mounting protrusion may be hemispherical or kamaboko. In the case of a hemispherical mounting protrusion, the contact with the wafer is theoretically a point contact when the wafer is mounted, but in reality the contact part sinks a little due to the weight of the wafer (substantially circular) Surface contact. In the case of a semi-cylindrical mounting protrusion, the contact with the wafer is theoretically a line contact when the wafer is mounted, but in reality, the contact portion sinks slightly due to the weight of the wafer (substantially rectangular) Surface contact).

  As the material constituting the container main body and the lid, high-molecular materials such as high-purity polycarbonate, polybutylene terephthalate, polyetherimide, cycloolefin polymer, and fluororesin that generate less impurity gas are used. In particular, the container in the wafer process generally uses a non-charged or conductive material obtained by mixing the polymer material with a conductive filler such as carbon fiber, carbon powder, or carbon nanotube. In addition, as materials used for wafer support ((wafer support) support plate and shelf), polypropylene, polybutylene terephthalate, polytetrafluoroethylene, polybutylene naphthalate, polyether ether ketone, fluororesin, polyethylene, polyethylene elastomer, polyolefin There are polymer materials such as elastomers. It is desirable to use conductive fillers such as carbon fiber, carbon powder, or carbon nanotubes that have been made non-charged or conductive, and contain containers and wafer supports ((wafer support) support due to static electricity) Particles and the like adhering to the plate portion, shelf, and mounting projection) can be suppressed.

  Further, as described above, a thermoplastic resin or a metal material having a melting point lower than that of the storage container body can be used as described above. When the container body is polycarbonate, for example, polybutylene terephthalate, polytetrafluoroethylene, alloy of polycarbonate and polytetrafluoroethylene, etc. as wafer support ((wafer support) support plate, shelf or mounting projection) material Can be used. When the container body is a cyclic olefin-based resin or a cyclic olefin-based copolymer, as a wafer support ((wafer support) support plate, shelf or mounting projection) material, for example, an alloy of these with polytetrafluoroethylene, etc. Can be used. Examples of the metal material include stainless steel, titanium, and aluminum. These metal materials are stronger than polymer materials and can be formed thinner. There is also an advantage that outgas is very small. Furthermore, what coat | covered these metal materials with the above-mentioned polymeric material can also be used. A wafer support ((wafer support) support plate, shelf or mounting protrusion) made of such a metal material coated with a polymer material is strong and has a smooth surface, so the shelf can be made thin. The amount of deformation can also be reduced. As a result, the shelf pitch can be reduced.

  The wafer storage container of the present invention can be used not only as a semiconductor pre-process and post-process as a process internal container but also as a shipping container. Although the description has been given mainly for the wafer storage container for storing the semiconductor wafer, it goes without saying that the wafer storage container of the present invention can be applied not only to the semiconductor wafer but also to a general thin plate. For example, the present invention can also be applied to a storage container such as a photomask or a reticle, a storage container such as a display element formation substrate such as a liquid crystal. Further, in the above description, it is needless to say that the contents described in a certain embodiment but not described in another embodiment can be applied in the embodiment even if they can be applied without contradiction.

  The present invention can be applied to the semiconductor industry using a wafer container used for transporting or storing semiconductor wafers.

[0003]
The wafer support includes a plurality of shelves that support a plurality of wafers aligned in the axial direction at predetermined intervals, a support plate portion that supports the shelf, and the support plate portion that is disposed inside the storage container body. A support plate attaching portion for attaching to the substrate, and a restricting portion for restricting the plurality of wafers formed on the support plate portion in a radial direction, and further, one or more holes are provided inside the shelf. It is characterized by. In addition, the shelf is formed on the upper surface of the shelf (on the side where the wafer is placed and on the side in contact with the back surface of the wafer), and one or a plurality of placements for supporting and placing the back surface of the wafer. Has protrusions.
[0007]
Further, the restricting portion is in contact with the conductor wafer only at the side end top portion of the semiconductor wafer or only at the side end top portion of the semiconductor wafer and the bevel portion of the semiconductor wafer. Further, the restricting portion is characterized in that the boundary with the shelf is inclined (the portion contacting the lower part of the bevel on the back surface of the semiconductor wafer is inclined). The wafer support is formed of a pair of opposing mirror image structures having a bilateral reference plane as a symmetry plane in the wafer storage container.
Therefore, when the lid is removed, the wafer storage container is placed horizontally, and the wafer is placed in the wafer storage container, the wafer is regulated by the placement projection and the regulating portion, and the wafer Does not touch any shelf other than the above-mentioned mounting protrusion. When the cover closes the opening of the storage container and stores the wafer in the storage container, the wafer is fixed by the wafer pressing member attached to the cover, the mounting protrusion, and the restriction portion. And the wafer does not contact any shelf other than the mounting protrusion.
Effect of the Invention [0008]
By using the wafer support of the present invention, the semiconductor wafer can be supported by a minute portion inside the wafer peripheral portion on the back surface of the wafer without contacting the wafer peripheral portion on the back surface of the wafer. Therefore, particles or the like that wrap around from the back surface side of the semiconductor wafer to the front surface side of the semiconductor wafer can be extremely reduced. Further, since the inner surface of the back surface of the wafer is further supported by the mounting protrusions, the amount of deflection of the wafer can be minimized. In particular, in the case of a large-diameter wafer, since the amount of deflection of the wafer becomes large, the effect of the wafer support of the present invention is great. Moreover, the fact that the amount of deflection can be reduced leads to a reduction in the wafer pitch stacked on the wafer storage container, and as a result, the number of wafers that can be stored in the wafer storage container can also be increased. Furthermore, when the semiconductor wafer is taken in and out, the semiconductor wafer is (is) placed on the plurality of placement protrusions, so that the semiconductor wafer can be stably placed horizontally. As a result, the semiconductor wafer is not damaged.
[0009]
Further, the structure of the restricting portion is configured such that only the wafer side top portion or the wafer side end top portion and the wafer bevel portion are in contact with the wafer, thereby forming a semiconductor device.

[0026]
Since it has an equilateral triangular shape, even if a large-diameter wafer is supported, the bending is small and the twist is minimized. In FIG. 15, since there are two wafer supports, the wafer is supported by four isosceles triangular sub shelves. In general, the maximum number of sub shelves is determined by the angle (vertical angle), the equilateral length, and the (wafer support) support plate portion size at which the tips of one isosceles triangle intersect.
[0063]
The mounting protrusions 336 (336-1, 336-2) and 337 (337-1, 337-2) shown in FIG. 15 are formed in the vicinity of the apex facing the bottom of the isosceles triangular subshelf. That is, a first placement protrusion 336-1 is provided near the apex of the first subshelf 334-1, and a second placement protrusion 336-2 is provided near the apex of the second subshelf 334-2. Further, a first placement protrusion 337-1 is provided in the vicinity of the vertex of the subshelf 335-1 at a symmetrical position, and a second placement protrusion 337-2 is provided in the vicinity of the vertex of the subshelf 335-2. Since the four isosceles triangles shown in FIG. 15 have the same size, the positions of the mounting protrusions formed at the vertices are located at approximately the same distance from the peripheral edge of the wafer mounted thereon. Support the back side. That is, the mounting protrusion is in an annular region, in other words, is formed so as to be disposed on a substantially concentric circumference of the wafer when the wafer is mounted. Accordingly, since the weight of the wafer is distributed to the mounting projections to the same extent, the deflection due to the weight of the wafer becomes more uniform. When the shelf (sub-shelf is the same) is horizontal, as described above, the shelf also deforms downward depending on the strength of the shelf and the weight of the wafer, but the isosceles triangle shape shown in the figure is the shape that minimizes deformation. It is one of. In order to further reduce the amount of deformation, the shelf is inclined upward with respect to the wafer surface as shown in FIG. That is, the shelf is formed so as to incline upward from the base portion of the shelf and the (wafer support) support plate portion toward the front end portion of the shelf toward the wafer center (axis) side. Thus, by making the shelf into a plurality of substantially isosceles triangle shapes and inclining the shelf, the deformation of the shelf can be suppressed and the wafer can be supported by only the mounting projections. As a result, the deflection of the wafer itself can be greatly reduced.
[0064]
Since the shelf and the mounting projection are usually resin-molded, a mold according to the shape of the shelf and the mounting projection is prepared by pouring resin into the mold (for example, injection molding).
[0065]
FIG. 19 is an enlarged schematic view of the wafer support (support plate portion and shelf) shown in FIG. The shelf 513 has the aforementioned angle with respect to the (wafer support) support plate 511.

Claims (11)

A storage container body having at least one opening; a lid that closes the opening; a seal that airtightly isolates the interior of the storage container body from the external environment when the storage container body is closed by the lid; In a wafer storage container having a wafer support that is formed inside the storage container body and supports the wafer in alignment.
The wafer support is
A plurality of shelves for supporting a plurality of wafers aligned in the axial direction at predetermined intervals; and
A support plate for supporting the shelf;
A support plate mounting portion for mounting the support plate portion inside the storage container body;
A restricting portion for restricting the plurality of wafers formed on the support plate portion in a radial direction;
And having
One or more holes are opened inside the shelf.   The shelf has one or a plurality of mounting protrusions for supporting and placing the back surface of the wafer on the upper surface of the shelf (the side that is on the top when the wafer is mounted). The wafer storage container according to claim 1.   The wafer storage container according to claim 2, wherein the placement protrusion has a hemispherical shape or a kamaboko shape.   The placement protrusions are arranged in an angle range of 0 degrees to δ degrees from the facial reference surface of the storage container body toward the opening side and the back side (bottom side) facing the opening, with the wafer center as the center. The wafer storage container according to claim 2, wherein δ is a value in the range of 30 to 70.   5. The wafer storage according to claim 2, wherein the mounting protrusion is disposed at a distance of 0.3 to 0.5 times the wafer diameter from the center of the wafer. container.   The wafer according to any one of claims 1 to 5, wherein the shelf is formed so as to be inclined upward from the base portion with the support plate portion toward the tip toward the wafer central axis side. Storage container.   The wafer storage container according to claim 6, wherein in the inclined shelf, an angle formed between the shelf and a wafer back surface supported by the shelf is 0.1 to 3.5 degrees.   The shelf reinforcing rib is formed between the surface of the shelf facing the wafer supported by the shelf and the support plate portion, according to any one of claims 1 to 7. Wafer storage container.   The shelf reinforcing rib is attached from the root of the shelf to the middle of the shelf with the support plate, and the dimension of the shelf reinforcing rib in the wafer axial direction is large at the base and gradually decreases as the shelf is halfway. The wafer storage container according to claim 8, wherein:   10. The wafer storage container according to claim 1, further comprising a rear shelf inside the back surface facing the opening of the storage container body. 10.   11. The wafer storage container according to claim 1, wherein the shelf and the rear shelf are made of a metal material covered with a polymer material.

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