Patent Publication Number: US-7216766-B2

Title: Thin plate storage container with handled supporting member

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a division of non-provisional application 10/712,014, filed Nov. 14, 2003, now U.S. Pat. No. 7,017,750. This application claims, under 35 USC 119, priority of Japanese Application No. 2002-349457 filed Dec. 2, 2002 and Japanese Application No. 2003-35062 filed Feb. 13, 2003. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a thin plate storage container, in which the load on the container body in transportation is reduced to improve sealing. The present invention further relates to a thin plate storage container for securely supporting a plurality of thin plates stored within the container body. 
     The transportable containers for containing and transporting semiconductor silicon wafers are generally known. In such a wafer container, it is important to keep its inside clean to prevent dirt and the like from collecting on the surfaces of contained semiconductor silicon wafers during transportation. For this purpose, the container is sealed tightly, usually by a sealing member on the lid of the container, which sealing member contacts the container body to seal it when the lid closes the container body. 
     In addition, the thin plate storage containers have a handle on each side of to be gripped for carrying by hand. 
     Semiconductor silicon wafers are stored in the in the above-mentioned containers for transfer to a semiconductor manufacturing factory and the like, where the container goes through a production line. 
     Moreover, it is necessary that the wafer container support the semiconductor silicon wafers at regularly spaced intervals to keep them from contacting each other. Therefore supporting members are placed on both the interior of the container body and on the interior side of the lid to support semiconductor silicon wafers at regularly spaced intervals. 
     An example of a supporting member incorporated into a lid is illustrated in  FIG. 26 . This supporting member is disclosed in Japanese TOKUHYOHEI No. 5-507817. As shown in  FIG. 26 , an upper cover  35  has a holder  36  for supporting semiconductor silicon wafers from above, mounted on its inner side. The semiconductor silicon wafers  37  are stored in the container body (not illustrated) positioned below the upper cover  35 . 
     The wafer holder  36  has supporting arm portions  38  alternately extending from right and left. Base ends of the supporting arms  38  are fixed to the interior side of upper cover  35 , and the opposite ends extend toward the semiconductor silicon wafers  37 . A holddown member  39  at the tip of each of the supporting arm  38  engages an edge portion of a semiconductor silicon wafers  37  to support each semiconductor silicon wafer  37  at regularly spaced intervals. 
     In order to manually lift and lower for transport and the like, a worker grips the handles to hold the thin plate storage container. However, since the handles are located on the sidewalls of the thin plate storage container, the sidewalls receive a load when the thin plate storage container is lifted, whereby the opening of the container body can be slightly distorted and the sealing member can slip slightly. This effect is undesirable although there is no problem with the sealing. 
     There is a slight gap between the container body and the lid when the container body is fitted with the lid. Although there is no problem in normal use of the thin plate storage container, there is the possibility that the thin plate storage container will receive a shock when the thin plate storage container is mounted in use. In this case, the lid can slip because of the gap between the container body and the lid and the sealing member will also slip. In such an event, although there is no sealing problem, the result is not the desired perfection. 
     Moreover, in the thin plate storage container having the above-described structure, each of the supporting arm portions  38  of the wafer holder  36  is cantilevered such that base end of the arm is fixed to the upper cover  35  and the distal end is free. The supporting arm portions  38  thereby hold the semiconductor silicon wafers  37  with a comparatively weak force, and it is difficult to strongly hold the semiconductor silicon wafers  37 . Therefore, it is difficult to securely hold a semiconductor silicon wafer  37  of a large radius and heavy weight and there is the problem that the semiconductor silicon wafers  37  shake within the container. 
     Because the wafer holder  36  is cantilevered, i.e. each holddown member  39  pivots about its base, if the semiconductor silicon wafers  37  slip, there is the problem that friction is generated between the holddown members  39  and the semiconductor silicon wafers  37  and particulate matter thereby generated. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to provide a thin plate storage container wherein the lid is prevented from slipping, the load on the container body in conveyance is reduced to improve sealing, and a plurality of the thin plates can be securely held within the container body. 
     The thin plate storage container of the first embodiment of the present invention comprises a container body, for storing a plurality of thin plates, and a lid for closing and sealing the container body. The lid is taken off to remove and insert the thin plates into the container body lying broadwise. The container body includes four side walls extending to a lid receptacle (flange) for receiving the lid and surrounding the opening of the container body, and lid support inserts located on at least the bottom edge of the lid receptacle when the container body lies broadwise, to support the lid. Lid edge inserts, e.g., corner inserts located on the periphery of the lid opposite the lid support inserts, cooperate with the lid support inserts to support the lid. 
     Owing to the lid support inserts in the lid receptacle of the container body directly contacting the lid edge inserts on the periphery of the lid or with a slight gap therebetween when the lid is placed on the container, if the container body receives a shock through careless handling of the thin plate storage container, the lid will not slip from the container body. 
     It is preferred that each of the lid support inserts be formed as a convex dovetail to mate with a dovetail groove in the lid receptacle, and that the contacting surface of each of the lid support inserts be planar. 
     The lid receptacle is a flange including four corner portions, four planar edge surfaces connecting and integral with the four corner portions and a shoulder portion spaced from the container opening by the planar edge surfaces. 
     Generation of dust and the like can be kept to the minimum because each contacting surface is planar. The material of the lid support inserts and that of the corner inserts are selected to minimize dust generation when they are rubbed by each other. 
     It is preferable that each of the corner inserts includes a fixing plate portion to be inserted into and fixed in an engagement groove located at a corner of the lid, and that the contacting plate portion of the corner insert be curved to conform to the corner of the lid and that the outside of the contacting plate portion form planar contacting surfaces for contacting the lid support inserts. 
     The contacting plate portion is positioned to cover a corner of the lid by insertion of the fixing plate portion into the engagement groove at the corner of the lid. Thus mounted, the planar contacting surfaces, at both ends of the contacting plate, are in contact with a lid support insert to support the lid. Thereby, the lid scarcely slips when the container body receives a shock, and sealing quality is improved. 
     The thin plate storage container of the second embodiment comprises a container body for storing and holding a plurality of thin plates in a clean condition, and a lid for closing and sealing the interior of the container body. When the container body is lying broadwise, it rests on a supporting member fitted thereto, and which comprises a base plate positioned under and supporting the container body, when lying broadwise, and side plates extending from opposing ends of the base plate portion. 
     Handles are provided on the side plates for lifting the container body. When these handles are gripped and lifted, the supporting member is held directly, with the container body supported by the base plate. Thereby, any distortion caused by lifting is absorbed by the base plate and the side plates of the supporting member, so that any ill effect on the container body is minimized. 
     It is preferable that detents be provided in opposing side walls of said container body so that the container body can be supported more securely by the supporting members by engagement with lugs on the opposing sidewalls of the container body with the side plates of the supporting member. 
     It is preferable that conveyor rails be provided on the side plates of the supporting member so that the thin plate storage container  1  can be transferred by suspension from the conveyor rails of a conveyor in a production line or the like without any further attachment or modification. 
     It is preferable that positioning means be provided on the base plate portion of the supporting member for precise adjustment of the mounting position of the container body. 
     The thin plate storage container of the third embodiment comprises a container, for storing and supporting a plurality of thin plates in clean condition, a lid for closing and sealing the container body, and a thin plate supporting member on the inner surface of the lid to support the thin plates at regular intervals. The thin plate supporting member comprises contacting portions for engaging the periphery of each of the thin plates, supporting portions which elastically support the contacting portions, and a base support bar fixed to the inside of the lid to integrally support all of the plurality of the supporting portions aligned in parallel at regular intervals. Each base of the supporting portions is integrally connected with the base support bar, and the contacting portions are positioned in the middle of the supporting portions, and the tip of the supporting portions contact the inner surface of the lid to elastically support the contacting portions from both sides. Thin plates having large diameter and heavy mass can thereby be held securely because the supporting portions elastically support the contacting portions from both sides. 
     It is preferable that base side of each supporting portion be formed relatively long, and that the tip side be formed relatively shorter. Since the distance between the base support bar portion and each of the contacting portions is relatively long, the supporting portions push the contacting portions of the thin plate with a weak force. In addition, because each tip side of the contacting portions is in contact with the inner surface of the lid, the contacting portions are elastically supported from both sides. The contacting portions are pushed toward the periphery of the thin plates with a strong force since the tip sides extending from the contacting portions are relatively short. Although there is no difference in elastic coefficient between the two portions on opposite sides of each contacting portion, the supporting portions support the contacting portions with strong force since the tip sides are relatively short. 
     It is preferable that the supporting portions are formed to extend, at both sides of the contacting portions toward the thin plates within the container body, so as to exert a strong elastic force. 
     It is preferable that support stages be provided on the inner surface of the lid to support the tip ends of the supporting portions. Thus, the supporting portions are supported from both sides by the support stages on the inner surface of the lid to support the tips of the supporting portions. Therefore the contacting portions are supported by the supporting portions from both sides. 
     It is preferable that engagement portions which engage and support the tip ends of the supporting portions are formed on the support stages, so that the tip of each of the supporting portions is supported securely by engagement with the engagement portions of the support stages. Therefore, the contacting portions are stably supported by the supporting portions. 
     It is preferable that support stages be fixed to the inner side of the lid to support the contacting portions elastically from the tip side, whereby the contacting portions are elastically supported by contact with the support stages fixed to the inner side of the lid. 
     The thin plate supporting members are arranged opposing each other, with the contacting portions of both aligned and spaced to support the thin plates at regular intervals. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial perspective view of a main part of a container body of a wafer storage container according to a first embodiment of the invention. 
         FIG. 2  is a perspective view of a container body of a wafer storage container according to a second embodiment. 
         FIG. 3  is a front view of a lid support insert. 
         FIG. 4  is a side view of the lid support insert of  FIG. 3 . 
         FIG. 5  is a top view of the lid support insert of  FIG. 3 . 
         FIG. 6  is a rear view of the lid support insert of  FIG. 3 . 
         FIG. 7  is a perspective view of a modified lid support insert. 
         FIG. 8  is a perspective view of a corner portion of the lid. 
         FIG. 9  is a perspective view of the lid. 
         FIG. 10  is a perspective view of a lid corner insert. 
         FIG. 11  is a top view of the lid corner insert of  FIG. 10 . 
         FIG. 12  is a perspective view of a supporting member. 
         FIG. 13  is a perspective view of the wafer storage container of the invention. 
         FIG. 14  is a top view showing the wafer storage container. 
         FIG. 15  is a perspective view of a main part of the wafer storage container. 
         FIG. 16  is a perspective view of a detent. 
         FIG. 17  is a perspective (“top”) view of a thin plate supporting member of a thin plate storage container according to the second embodiment. 
         FIG. 18  is a perspective view of the container body of the thin plate storage container according to the second embodiment. 
         FIG. 19  is a perspective view of the lid of the thin plate storage container according to the second embodiment. 
         FIG. 20  is a perspective view of the reverse side (bottom) of the thin plate supporting member of  FIG. 17 . 
         FIG. 21  is a side view showing the thin plate supporting member as shown in  FIGS. 17 and 20 . 
         FIG. 22  is a perspective view showing a strip projection on the lid of the thin plate storage container according to the second embodiment. 
         FIG. 23  is a perspective view of the thin plate supporting member of the second embodiment ( FIGS. 17 ,  20  and  21 ), mounted on the strip projections ( FIG. 22 ). 
         FIG. 24  is a side view of a first modification of the second embodiment. 
         FIG. 25  is a side view of the second modification of the second embodiment. 
         FIG. 26  is a sectional view of a main part of a thin plate supporting member of the prior art. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, the present invention will be described by way of two embodiments with reference to the attached drawings. 
     First Embodiment 
     In the first embodiment, a storage container to store and transport semiconductor silicon wafers as thin plates is given as an example. 
     This wafer storage container  1  comprises, as shown in  FIGS. 2 ,  9 , and  13 , a container body  2  for supporting a plurality of semiconductor silicon wafers (not shown), and wafer supporting plates (not shown) on the inside surface of two sidewalls inside of this container body  2  facing each other to support a plurality of semiconductor silicon wafers, stored in parallel and at regular intervals, from both sides of the wafer. A lid  3  seals the upper opening of the container body  2  and keeps the inside clean. A supporting member  4  supports the container body  2 . 
     The container body  2  is formed generally in the shape of a cube. For supporting detachable wafer supporting plates, a plurality of supporting protrusions  6  is placed on rear side and back side, inside of sidewall portions  2 A and  2 B of the container body  2 . A lid receptacle  7  surrounds the opening of the container body  2  to engage with the lid. This lid receptacle  7  (flange) is formed by extending the upper edges of the side walls of the container body  2  to the outer diameter of the lid. 
     Engagement slots  8  are formed in the lid receptacle  7  to engage with stop rollers  14  of the lid  3  ( FIG. 9 ). These engagement slots  8  are provided at each of four corners. 
     Lid support inserts  10  are placed at each of the four corners of the lid receptacle. Lid support inserts  10  are, as shown in  FIG. 1–6 , formed like wedges having dovetail on both sides to engage dovetail grooves on the lid receptacle  7 . At the center surface of each lid support insert  10 , a protruding ridge  11  extends the entire length of the lid support insert. A taper is formed on the outside of the protruding ridge  11  (right side of  FIG. 4 ) to prevent contact with corner inserts  16  when the lid  3  is attached and detached. On the rear side of the protruding ridge  11  is a contact protrusion  11 A. This contact protrusion  11 A is positioned to contact a corner insert  16 , and is formed flat. Since there is a taper on the contact protrusion  11 A, uneven contacting pressure results over all the contacting surface, and dust is generated. Besides, although the contact protrusion  11 A is narrow because of the configuration of the protruding ridge  11 , the area of the contact protrusion  11 A is set to provide a balance between load and friction. It is preferable that the contact protrusion  11 A be as narrow as possible since there is a possibility of contact between the corner insert and the lid support insert  10  when the lid  3  is attached and detached. On the other hand, the protruding ridge  11  must support the weight of the lid  3 . For this reason, the area of the contact protrusion  11 A is minimized to balance the weight of the lid  3 . If the lid  3  is large and heavy, to broaden its contacting area, the protruding ridge  11  can be omitted as in  FIG. 7 . 
     A pair of lid support inserts  10  is placed at each four corners of the lid receptacle  7 . In particular, the pair of lid support inserts  10  is engaged with a pair of dovetail grooves on each of four corners of the lid receptacle  7 , so that each pair of the lid support inserts  10  at each corner of the lid receptacle  7  supports each corner of the lid  3  squarely. 
     The lid  3  is, as shown in  FIGS. 8 and 9 , formed as a thick quadrangular plate and mates with the lid receptacle  7  of the container body  2 . A flange portion  3 A is formed on the outer side of the lid  3  (lower part of  FIG. 9 ) to cover the outside of the lid receptacle  7  when the lid  3  is seated within the lid receptacle  7 . A stop roller  14  is located near each corner of the lid  3 . On the surface of the lid  3 , a pair of key openings (shown in  FIG. 13 ) is provided to retract each stop roller  14  freely. The stop roller  14  is connected by a link (not shown) whereby it is extended to engage within an engagement slot  8  by insertion and rotation of the key. The key is placed on an arm of a transport mechanism in a production line or the like, and then the lid  3  is automatically attached and detached. A sealing member (not shown) is placed on the inside periphery of the lid  3 . 
     Corner inserts  16  are located at each corner of the lid  3 . These corner inserts  16  contact the lid support inserts  10  of the container body  2  to support the lid  3 . Each of the corner inserts  16  includes a fixing plate portion  17  and a contacting plate portion  18 , as shown in  FIGS. 10 and 11 . The fixing plate portion  17  has a shaft hole  17 A, and the fixing plate portion  17  is inserted into and fixed within a groove (not shown) at each corner of the periphery of the lid  3 . The contacting plate portion  18  is curved to cover a corner of the lid  3 . Both sides of the outer surface of the contacting plate portion  18  are formed as flat (planar) contacting surfaces  18 A for contact with the contact protrusion  11 A of the lid support inserts  10 . Support legs  18 B are formed at both ends of the contacting plate portion  18 . These support legs  18 B bend inward to support the contacting surface  18 A by contact with peripheral wall of the lid  3 . Each contacting surface  18 A contacts a contact protrusion  11 A of the lid support insert  10  to support the lid  3 . Therefore, if the lid body  2  receives a shock, the lid  3  does not slip. 
     The material of the lid support inserts  10  and the corner insert  16  must be a material that generates little dust when these elements contact each other. In particular, PBT (polybutylene terephthalate) resin, PEEK (polyether ether keton) resin, polyacetal resin, supermacromolecular PE (polyethylene) resin, or nylon resin is used as the material of the lid support insert  10 . Alternatively, PTFE (polytetrafluoroethylene) and/or carbon fiber are also suitable. PBT resin, PEEK resin, polyacetal resin, supermacromolecular PE resin, nylon resin, and PTFE and/or carbon fiber, in addition to the five aforementioned materials, are suitable for the corner insert  16 . These materials may be suitably paired so as to generate little dust by friction. 
     On the rear side of the lid  3 , there is a thin plate supporting member  40 , the structure of which is described in more detail in connection with the second embodiment below. 
     Supporting member  4 , which supports the container body  2 , comprises, as shown in  FIG. 12–16 , a base plate portion  21 , sidewalls  22  and  23 , and handles  24 . 
     The base plate portion  21  is a plate which directly supports the container body  2 . The base plate portion  21  supports the container body  2  (lower part in  FIG. 13 ) when laid on its side. The supporting member  4  and the container body  2  are fastened to each other by screws with a plurality of supporting bars  26 , placed on the surface of the base plate portion  21  and supporting the container body  2 . In addition, positioning engagement portions  27  (“positioning means”) are provided on the base plate portion  21  for adjusting the mounting position of the thin plate storage container. This storage container is provided with three engagement elements,  27 A,  27 B, and  27 C. Each of the three engagement elements,  27 A,  27 B, and  27 C, consists of a V-shaped groove. The angle between the longer axes of the engagement elements,  27 A,  27 B, and  27 C is generally 120°, and the three engagement elements are oriented in three different directions. The dimensions, angle and the like of the positioning engagement portions  27  have been standardized. There are three engagement protrusions (not shown) at positions corresponding to the position of and mating with each of the engagement elements,  27 A,  27 B, and  27 C, when the container body  2  is mounted. These engagement protrusions control the position of the container body  2  precisely by respectively engaging the engagement elements  27 A,  27 B, and  27 C. 
     Side plates  22  and  23  extend perpendicular from opposite ends of the base plate  21 . Handles  24 , detents  28 , and conveyor rails  29  are provided on the side plates  22  and  23 . The handles  24  for lifting the container body  2  are formed integral with the upper ends of the side plates  22  and  23 . The detents  28  are located on the forward edges of the side plates  22  and  23  (near edge of  FIG. 12 ). The detents  28  are formed in the side plates  22  and  23  as thinned and hollowed recesses for receiving lugs  30  to be described below. 
     The lugs  30  are designed to securely support the supporting member  4  on the container body  2  by engaging with the detents  28  and thereby prevent the side plates  22  and  23  from opening. The lugs  30  are located on the outer surfaces of the side plates  2 A and adjacent the opening  2 B of the container body  2  (right side of  FIG. 15 ). The cross-section of the lugs  30  is L-shaped so that the lugs  30  engage the detents  28  on the side plates  22  and  23 . 
     The conveyor rails  29 , located on the outside of each side plate  22  and  23  allow the containers  1  to be suspended from and carried by conveyors of a production line or the like within a factory. The conveyor rails  29  are flat plates and are horizontally aligned along the entire length (longitudinal dimension) of each side plate  22  and  23 . 
     Reinforcement ribs are placed lengthwise and crosswise on the base plate  21  and side plates  22  and  23  to reinforce the entire body. 
     When semiconductor silicon wafers are placed in the container body  2  and then the lid  3  is put in place, the lid support inserts  10  on the lid receptacle  7  of the container body  2  and the corner inserts  16  of the lid  3  directly contact each other, or have a slight gap. The wafer storage container  1  is then conveyed to its destination in this state. 
     During conveyance, if the container body  2  receives a shock due to careless handling or the like, the lid support inserts  10 , in contact with the corner inserts  16 , support the lid  3  to prevent slip of the lid  3  from the container body  2 . 
     Generation of dust and the like is minimized because the lid support inserts  10  and the corner inserts  16  are made of PBT resin, PEEK resin, polyacetal resin, supermacromolecular PE resin, or nylon resin, and each contacting surface,  11 A and  18 A, is planar. 
     When holding the handles  24  and lifting the wafer storage container  1  the supporting member  4  is held directly, and the container body  2  is supported by the base plate  21 . At this time, the side plates  22  and  23  are supported without opening since the latch fingers  30  on the sidewalls  2 A and  2 B of the container body  2  engage with the finger receptacle portions  28  on the side plate portions  22  and  23  of the supporting member  4 , and when the handles  24  are held to lift the wafer storage container  1 , the side plate portions  22  and  23  are stabilized without vacillation. There is no distortion or the like when held by the handles  24  because the distorting force is absorbed by the side plates  22  and  23  of the support member  4  and the base plate  21 , and the affect on the container body  2  is thereby minimized. Therefore, there is no adverse effect on the sealing member between the container body  2  and the lid  3 . 
     In a production line or the like in a factory, the conveyor rails  29  are held by a conveyor to transport the container. In addition, the positioning engagement elements  27  are used to precisely position the container body  2  when the container is mounted on a mounting stand. 
     As described above, if the container body  2  receives a shock, the lid support inserts  10  and the corner inserts  16  directly contact each other and the lid is supported without slip from the container body  2 . Moreover, slip of the sealing member between the container body  2  and the lid  3  is prevented and the sealing quality of the seal of the wafer storage container  1  is thereby improved. 
     Generation of dust and the like is minimized because the contact protrusion  11 A of each lid support insert  10  and the contacting surface  18 A of the corner insert  16  are planar and the material of each contacting surface is carefully selected. 
     Modifications: 
     (1) Although the lid support inserts  10  and the corner inserts  16  are provided at each of four corners of the lid  3  in the first embodiment, the lid support inserts  10  and the corner inserts  16 , alternatively, can be provided only on the lower edges of the container body  2  and lid  3 . In this case, the same advantage as in above-described embodiment is achieved when the container is handled. The lid support inserts  10  and the corner inserts  16  can be placed on all of the four edges of the lid and lid receptacle or on one edge only, according to the intended use. 
     (2) The base plate  21  and the side plates  22  and  23  of the supporting member  4  are formed so that they can support the container body  2  and the handles  24 , so various shapes, not only planar, can be adopted for them. 
     Second Embodiment 
     The second embodiment of the present invention is also illustrated, by way of example, as a storage container to store and carry thin-plate semiconductor silicon wafers (thin plates). 
     This wafer storage container  41  of the second embodiment, as shown in  FIG. 18  and  FIG. 19 , comprises a container body  42  for storing a plurality of semiconductor silicon wafers (not shown) therein. Wafer support plates  43  are provided on opposite side walls in the container body  42  for supporting the semiconductor silicon wafers from opposite sides of the wafers, which are stored within the container body, in parallel and at regular intervals. Lid  44  seals the upper opening of the container body  44  and keeps the container&#39;s inside clean. 
     A lid receptacle  45  is provided around the opening of the container body  42  to engage the lid  44 . This lid receptacle (flange)  45  is similar to flange  7  of the first embodiment and is formed by enlarging the edges of the container body  42  surrounding the opening to meet the dimension of the lid. Various fixing means (not shown) are placed between the lid  44  and the lid receptacle  45  to fix the lid  44  onto the container body  42 . 
     A carrier flange  46  ( FIG. 18 ) is engaged by an arm of a carrier mechanism (not shown) on a production line when the container is carried. A handle is provided to enable a worker to carry the container by hand. 
     Thin plate supporting member  51  is fixed on the inner side of the lid  44  (upper side in  FIG. 19 ). The thin plate supporting member  51  serves to support the upper edges of the stored semiconductor silicon wafers at regular intervals. The thin plate supporting member  51  will next be explained with reference to  FIG. 17  and  FIG. 19–23 . 
     The thin plate supporting member  51  includes contacting portions  52  which engage the peripheries of the semiconductor silicon wafers and thereby support the semiconductor silicon wafers. The contacting portions  53  are, in turn, elastically supported by supporting portions  53 . A base supporting bar  54  located on the inner side of the lid  44  (upper side of  FIG. 19 ) supports a plurality of the supporting portions  53  in parallel, integrally and at regular intervals. 
     Engagement grooves  56  are formed in the surfaces of the contacting portions  52  facing the semiconductor silicon wafers. These engagement grooves  56  serve to engage the peripheries of the semiconductor silicon wafers to support the wafers. The supporting portions  53  are provided integrally on both sides of the contacting portions  52 . 
     The supporting portions  53  are formed integral with the contacting portions  52  to support them. The supporting portions  53  are formed in the shape of rods, are made of an elastic synthetic resin, and support the contacting portions  52 . The contacting portions  52  are positioned at the middle of the supporting portions  53 . Therefore the contacting portions  52  divide the base supporting portions  53 A from the tip supporting portions  53 B. Each base end of the tip supporting portions  53 B is formed integral with a contacting portion  52 . Caul plate portions  55  are formed at the ends of the tip supporting portions  53 B. The caul plate portions  55  engage the engagement portions  62 A of supporting stages  62  (as shown in  FIG. 23 ) to support the tip supporting portions  53 B. The contacting portions  52  are thereby elastically supported by the base supporting portions  53 A and the tip supporting portions  53 B from opposite sides. 
     The base supporting portions  53 A are formed relatively long, and the tip supporting portions  53 B are shorter. Since the base supporting portions  53 A are longer, the base supporting portions  53 A press the contacting portions  52  onto the periphery of the semiconductor silicon wafers with a weak force at first when the contacting portions  52  contact the peripheries of the semiconductor silicon wafers. Then, since the tip supporting portions  53 B are shorter, the caul plate portions  55  at the end of the tip supporting portions  53 B contact the inner surface of the lid  44 , and support the contacting portions  52  with a strong force, whereby the contacting portions  52  are pressed onto the peripheries of the semiconductor silicon wafers with a strong force. 
     Depending on the situation, there may be gaps of a predetermined width between the tip supporting portions  53 B and the engagement portions  62 A of the supporting stages  62  ( FIG. 23 ). If a gap is present, the contacting portions  52  are supported by only the base supporting portions  53 A from one side and therefore support the semiconductor silicon wafers with a weak force. In addition, if the semiconductor silicon wafers are shaken hard by an external force such that the wafer storage container  41  is swung or the like, the contacting portions  52  are pushed and thereby the tip supporting portions  53 B come into contact with the engagement portions  62 A of the supporting stages  62  to elastically support the semiconductor silicon wafers with a strong force. On the other hand, if gaps are not present, the semiconductor silicon wafers are supported with strong force from the start. 
     In the supporting portions  53 , both sides of the contacting portions  52  are formed to protrude in the direction of the semiconductor silicon wafers stored in the container body  42 . Slanted portions of the supporting portions  53  serve to enhance the elastic force of the supporting portions  53 . 
     Base supporting bars  54  are integral with and support supporting portions  53  in parallel and at regular intervals. These base supporting bars  54  are also engaged with support grooves  64  ( FIG. 22 ) to be fixed on inner side of the lid  44 . 
     Projecting strips  61  on the inner side of the lid  44  support the tips of the supporting portions  53 . The strips are formed with supporting stages  62  and supporting recesses  63  aligned alternately. Two supporting recesses  63  are arranged in parallel on the inner side of the lid  44 . This structure supports caul plates  55  opposite two thin plate supporting members  51 . The supporting stages  62  of one strip are aligned with the supporting recesses  63  of the other strip projection. Namely, the supporting stages  62  and the supporting recesses  63  are arranged opposing each other. 
     The supporting stages  62  of the strips  61  support the caul plates  55  on the distal ends of the supporting portions (arms)  53 . The engagement portions  62 A are formed on the supporting stages  62  to engage the caul plates  55  on the tips of the supporting portions  53  and to support the caul plates  55 . The engagement portions  62 A are formed as recesses and engage the caul plates  55  to prevent rightward and leftward slip. 
     The supporting recesses  63  engage and support the base supporting portions  53 A. The supporting recesses  63  are cut deeper into strips  61  than the supporting stages  62 . The height of the supporting recesses  63  is set optimally according to the intended use. If a user wants to support the semiconductor silicon wafers with strong force, the height of the supporting recesses  63  should be set so that the base supporting portions  53 A are in contact with the supporting recesses  63 . On the other hand, if a user does not wants to support the wafers with strong force, the height of the supporting recesses  63  should be set so that the base supporting portions  53 A are not in contact with the supporting recesses  63 . 
     The two strip projections  61  are provided with grooved supports  64  to engage and support the base support bars  54  of the thin plate supporting member  51 . The grooves of the grooved supports  64  are sized to mate with the base support bars  54 . Two base supporting bar portions  54  of the thin plate supporting members  51  opposing each other are fitted within the grooves of grooved supports  64 , and are thereby aligned to support the semiconductor silicon wafers at regular intervals. The two thin plate supporting members  51  have the same structure and are opposed to each other. 
     In use, a plurality of semiconductor silicon wafers is stored inside the container body  42  wherein they are supported by the wafer supporting plates  43  at regular intervals. The lid  44  is then fitted on the container body  42  whereby the contacting portions  52  of the thin plate supporting members  51  engage and support each semiconductor silicon wafer. 
     When the lid  44  is fully seated in the lid receptacle  45 , the contacting portions  52  are pushed up by the silicon wafers toward the inner side of the lid  44 . Thereby the base supporting portions  53 A, support the contacting portions  52  with a weak force which is received by the semiconductor silicon wafers. However, if the caul plate portions  55  engage the engagement portions  62 A of the supporting stages  62 , the contacting portions  52  are supported from both sides, and the semiconductor silicon wafers are then supported by a stronger force. Further, if the base supporting portions  53 A come into contact with the supporting recesses  63 , then the supporting stages  62  and the supporting recesses  63 , opposite each other, also support the contacting portions  52 , i.e. support the supporting portions  53  directly and the contacting portions  52  indirectly, whereby each semiconductor silicon wafer is supported by a yet stronger force. 
     The above-described structure serves to support both small light semiconductor silicon wafers and large heavy semiconductor silicon wafers securely with optimum force. 
     Moreover, almost no dust is generated at points of contact, so generation of dust and the like can be minimized. 
     Since the thin plate supporting member  51  is formed so that the contacting portions  52  are aligned oppositely and alternately, the distance between the contacting portions  52  and between the supporting portions  53  of the thin plate supporting member  51  can be relatively wide and the thin plate supporting members  51  can be molded more easily. The structure of the metal mold can be simplified, whereby the metal mold can be made inexpensively and the production cost of the thin plate supporting member  51  can be reduced. 
     Modifications of the Second Embodiment 
     (1) Although two thin plate supporting members  51  are used in the second embodiment as described above, one, two or more than three thin plate supporting members  51  can also be used according to the number of the semiconductor silicon wafers to store and the same function and effect as in the above-described embodiments can be obtained. 
     (2) Although the supporting stages  62  are placed on the inner side of the lid  44  to support the tip ends of the supporting portions  53  in the second embodiment, it is also possible to locate the supporting stage portions  71  on the caul plate portions  55  as shown in  FIG. 24 . Further, as shown in  FIG. 25 , it is also possible to elongate and extend the tip (distal) supporting portions  53 B to the inner side of the lid  44  to become lid support inserts  72 , while realizing the same function and effect as in as above-described embodiments. 
     (3) Although semiconductor silicon wafers are mentioned as an example of thin plates in the foregoing description of the first and second embodiments, other thin plates, such as glass plates, memory discs and the like, can be also be used within the thin plate storage container of present invention.