Patent Publication Number: US-10781026-B2

Title: Container and package

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. National Phase Application under 35 U.S.C. 371 of International Application No. PCT/JP2017/024590, filed on Jul. 5, 2017, which claims the benefit of priority from Japanese Patent Application Nos. 2016-135876 and 2016-135877, both filed on Jul. 8, 2016. The entire disclosures of these applications are incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a container and a package. 
     BACKGROUND ART 
     Recently, due to a miniaturization of electronic devices, electronic components used for the electronic devices also have become significantly smaller in size, and yet constructed as multifunctional components having a number of functions. Such multifunctional components include a Ball Grid Array (BGA), a Chip Size Package (CSP), and the like to which a number of electrodes are installed. When the multifunctional component is to be mounted in a printed board, solder is applied between the electrodes and lands of the printed board. 
     To an electronic component, such as a Quad Flat Package (QFP) and a Small Outlined Integrated Circuit (SOIC), a bare chip including internally a number of electrodes is installed, and these electrodes are soldered to a substrate of the electronic component. 
     In the soldering as described above, if the solder is individually supplied to a number of installation locations or to significantly small electrodes, an excessive labor is taken. Furthermore, accurately and individually supplying fine soldered portions with the solders is difficult. Accordingly, in the soldering involving the multifunctional components or the bare chip, the solder is previously attached to the electrode to form a solder bump, and the solder bump is melted during soldering for soldering. 
     For formation of such solder bump, a method using a solder paste, a solder ball, or the like is used. The method using the solder paste, which is inexpensive in terms of cost, has been conventionally used predominantly. However, since a micro size of formed bump in a range of 30 to 200 μm has been requested, and a height in mounting can be further secured with the bump formed with the solder ball compared with the bump formed with the solder paste, the method using the solder ball having a diameter equal to a requested bump height has been widely used. Especially, the use of the solder balls is indispensable in an electrode for an external terminal of the BGA and the CSP or an electrode for a bare chip joining inside a component where securing the height in mounting is important. 
     To mount the solder balls on a number of electrodes, the solder balls are put on a pallet with holes having diameters smaller than those of the solder balls formed, and the pallet is swung. Thus, the solder balls are aligned on the holes on the pallet. Then, the solder balls are mounted on a solder ball mounting head. Accordingly, if an aspect ratio of the solder ball is large or there is an error in grain diameter, the solder ball cannot be mounted to the electrode. Thus, it is important that there is no error in grain diameter of every one of the solder balls in order to secure a precise amount of solder and secure the height in mounting. 
     In addition, as the solder balls become minute, a ratio of a surface area of the solder balls to total volume of the solder increases; therefore, the surfaces of the solder balls are likely to become oxidized and turn into yellow. Such yellowing is due to the fact that the solder balls are exposed to the atmosphere and Sn in the solder balls is oxidized by oxygen in the atmosphere. Since a color of an oxide film of the Sn is yellow, the thickened oxide film causes the entire solder ball to appear yellowish. 
     In contrast to this, there has been known a package for storing minute solder balls where containers housing the minute solder balls are made of a breathable material and a deoxidizing and drying agent arranged outside the containers is housed in a bag member together with the containers to be airtightly sealed (see PTL 1). This allows preventing the oxidization and the yellowing of the solder ball surface. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Patent No. 4868267 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in a solder ball container disclosed in PTL 1, to house solder balls having a small grain diameter (for example, 0.1 mm or less), the solder ball is possibly sandwiched in a fine gap between an edge of a container body of the solder ball container and a lid material. When the solder ball is sandwiched in the above-described gap, for example, the lid material moves with respect to the edge of the container body during conveyance of the solder ball container. This squashes the solder ball, causing a problem of deterioration of sphericity of the solder ball. 
     In the solder ball container disclosed in PTL 1, when the solder ball is electrically charged, metal particles possibly electrostatically adsorb to an inner surface and an opening end surface of the container body when the solder ball is taken out from the container body. The electrostatic adsorption of the solder ball to the opening end surface causes the solder ball to be sandwiched between the lid member and the opening end surface of the container body when the lid member is again mounted to the container body. This makes closing the lid member difficult and deforms the solder ball. 
     There has been also known a container housing, for example, a copper ball, a copper core ball, and a copper column. Similarly electrically-charging such metals possibly results in electrostatic adsorption to an opening end surface of the container. Since such metal has high strength compared with a solder, a possibility that the metal is sandwiched between a lid member and the opening end surface of a container body to deform is low. However, even these metals have the possibility of deformation more or less and therefore these metals are preferably not sandwiched between the lid material and the opening end surface of the container body. 
     The present invention has been made in consideration of the above-described problems. One of the objects is to provide a container and a package configured to prevent a deformation of housed metal. Another object is to provide the container and the package configured to prevent metal particles from attaching to an opening end surface of a container body. 
     Solution to Problem 
     According to a first aspect, there is provided a container. This container includes a cylindrical container body, a lid, and a flat plate-shaped inner plug. The cylindrical container body with a bottom has a sidewall and a bottom wall. The lid has a flat plate portion and a side portion. The flat plate portion covers an opening of the container body. The side portion covers at least a part of an outer peripheral surface of the container body. The flat plate-shaped inner plug is located inside the lid. The container body includes a thread ridge on the outer peripheral surface. The side portion of the lid has a screw groove with two or more threads on its inner peripheral surface. The lid is configured to be screwed with the container body by screwing the screw groove with the thread ridge. The inner plug includes an inner plug body and lock portions. The lock portions are disposed on an outer peripheral portion of the inner plug body. The screw groove has the threads by a count identical to a count of the lock portions. The inner plug is held to an inside of the lid by each of the lock portions fitted into each inside of the screw grooves. 
     According to a second aspect, in the container of the first aspect, at least an inner surface and an opening end surface of the container body have a conductive property. 
     According to a third aspect, there is provided a container. This container includes a cylindrical container body, a lid, and a flat plate-shaped inner plug. The cylindrical container body with a bottom has a sidewall and a bottom wall. The lid has a flat plate portion and a side portion. The flat plate portion covers an opening of the container body. The side portion covers at least a part of an outer peripheral surface of the container body. The flat plate-shaped inner plug is located inside the lid. The container body has an opening end surface. At least an inner surface and the opening end surface of the container body have a conductive property. 
     According to a fourth aspect, in the container of the third aspect, the container body includes a thread ridge on the outer peripheral surface. The side portion of the lid has a screw groove with two or more threads on its inner peripheral surface. The lid is configured to be screwed with the container body by screwing the screw groove with the thread ridge. The inner plug includes an inner plug body and lock portions. The lock portions are disposed on an outer peripheral portion of the inner plug body. The screw groove has the threads by a count identical to a count of the lock portions. The inner plug is held to an inside of the lid by each of the lock portions fitted into each of the screw grooves. 
     According to a fifth aspect, in the container according to any one of the first to the fourth aspects, the side portion of the lid has an inner surface having a gradient such that an inner diameter gradually decreases toward the flat plate portion. 
     According to a sixth aspect, in the container according to any one of the first to the fifth aspects, the flat plate portion of the lid has a ring-shaped protrusion. The protrusion has a flat portion at its distal end. The lock portions are each screwed into the screw groove along the screw groove to bring the inner plug body in contact with the flat portion and to bring the lock portions in contact with an inside of the screw groove to fix the lock portions to the inside of the screw groove. 
     According to a seventh aspect, in the container according to any one of the first to the sixth aspects, at least the inner plug has a conductive property. 
     According to an eighth aspect, in the container according to any one of the first to the seventh aspects, the bottom wall and the sidewall form a corner portion inside the container body. The corner portion is rounded off. 
     According to a ninth aspect, in the container according to any one of the first to the eighth aspects, the bottom wall has an inner surface formed to be flat. 
     According to a tenth aspect, there is provided a package. This package includes a holding member, a deoxidizing and drying agent, and a bag member. The holding member includes a receptacle. The receptacle receives the container according to any one of the first to the ninth aspects. The deoxidizing and drying agent is located outside the container. The bag member is impermeable to air. The bag member houses the container, the holding member, and the deoxidizing and drying agent. The bag member is hermetically sealed. 
     Advantageous Effects of Invention 
     The present invention can provide a container and a package that can prevent a housed metal from deforming. 
     Additionally, the present invention can provide the container and the package that can prevent metal particles from attaching to an opening end surface of a container body. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a container of this embodiment. 
         FIG. 2  is a cross-sectional view of a lid. 
         FIG. 3  is a bottom view of the lid. 
         FIG. 4  is an enlarged cross-sectional side view of a part of the lid illustrated in  FIG. 2 . 
         FIG. 5  is a side view of a container body. 
         FIG. 6  is a plan view of an inner plug. 
         FIG. 7  is a side view of the inner plug. 
         FIG. 8A  is a drawing illustrating a process to hold the inner plug to the lid. 
         FIG. 8B  is a drawing illustrating the process to hold the inner plug to the lid. 
         FIG. 8C  is a drawing illustrating the process to hold the inner plug to the lid. 
         FIG. 9  is a cross-sectional view illustrating a state where the inner plug is held to an inside of the lid. 
         FIG. 10  is a cross-sectional view of the container in a state where an opening of the container body is closed with the lid. 
         FIG. 11  is an enlarged cross-sectional view near a protrusion in the state where the opening of the container body is closed with the lid. 
         FIG. 12  is a drawing illustrating a state of a package before hermetic seal. 
         FIG. 13  is a vertical cross-sectional view of the package after the hermetic seal. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following describes embodiments of a container and a package of the present invention with reference to the drawings. In the drawings described later, the identical reference numerals are used for the identical or equivalent components, and therefore such components will not be further elaborated here. While metal particles of any metal species, such as a copper ball, a copper column, and a copper core ball, having any shape can be housed in the container of this embodiment in addition to a solder ball, the following embodiments give a description in the case of housing the solder ball. 
       FIG. 1  is a perspective view of the container of this embodiment. A container  10  includes a cylindrical container body  20  with a bottom and a lid  40  to close an opening (not illustrated) of the container body  20 . The container body  20  has an internal space configured to house the metal particles such as the solder ball. Closing the opening with the lid  40  closes this internal space. The lid  40  has a straight knurl  44  on the outer peripheral surface. When a user grips and rotates the lid  40  to screw the lid  40  with the container body  20 , the straight knurl  44  improves a friction force of a hand of the user with the lid  40 . The lid  40  does not hermetically seal the internal space of the container body  20  completely. The following describes details of structures of the container body  20 , the lid  40 , and an inner plug disposed inside the lid  40  constituting the container  10 . 
     First, the following describes the lid  40  illustrated in  FIG. 1 .  FIG. 2  is a cross-sectional view of the lid  40 ,  FIG. 3  is a bottom view of the lid  40 , and  FIG. 4  is an enlarged cross-sectional side view of a part A 1  of the lid  40  illustrated in  FIG. 2 . The lid  40  has a conductive property in one embodiment. Specifically, the lid  40  can be made of a material having the conductive property or the surface can be coated with a conductive material. As illustrated in  FIG. 2 , the lid  40  includes a flat plate portion  41 , which is configured so as to cover the opening of the container body  20  illustrated in  FIG. 1 , and a side portion  42 , which is configured so as to cover at least a part of the outer peripheral surface of the container body  20 . The side portion  42  is an approximately cylindrical member extending from the outer peripheral portion of the flat plate portion  41  in an approximately perpendicular direction. 
     A four-thread screw groove  43  is formed on the inner peripheral surface of the side portion  42 . Screwing the screw groove  43  with a four-thread thread ridge  28  (see  FIG. 5 ), which is formed on the outer peripheral surface of the container body  20 , causes the lid  40  to close the opening of the container body  20 . The number of threads of the screw groove  43  is not limited to four, and, insofar as the number is two or more, any number of threads is employable; however, two threads to four threads are preferred from an aspect of manufacturing. 
     As illustrated in  FIG. 3  and  FIG. 4 , the flat plate portion  41  includes a protrusion  45  circularly disposed along its outer periphery. The protrusion  45  has a flat portion  45   a  at its distal end. As described later, the protrusion  45  is configured such that the inner plug is sandwiched together with an opening end surface  24  (see  FIG. 5 ) of the container body  20  when the lid  40  is screwed with the container body  20 . 
     As illustrated in  FIG. 2 , the inner surface of the side portion  42  of the lid  40  has a gradient G 1  so as to gradually decrease in the inner diameter toward the flat plate portion  41 . The gradient G 1  is preferably about 1° or more to about 2° or less. In this embodiment, the gradient G 1  is formed at about 1°. Accordingly, the inner diameter of the screw groove  43  also gradually decreases toward the flat plate portion  41 . 
     Next, the following describes the container body  20  illustrated in  FIG. 1 .  FIG. 5  is a side view of the container body  20 . As illustrated in the drawing, the container body  20  includes a circular-flat-plate-shaped bottom wall  21  and an approximately cylindrical-shaped sidewall  22 , which extends from the bottom wall  21  approximately perpendicular to the bottom wall  21 . The sidewall  22  has an end portion constituting the opening end surface  24 , which forms the opening  23 . The sidewall  22  has an axial length configured to be larger than a diameter (outer diameter) of the bottom wall  21 . 
     The container body  20  includes the four-thread thread ridge  28 , which is disposed on the outer peripheral surface of the sidewall  22 , and a screw groove  25  corresponding to the four-thread thread ridge  28 . A flange  26  and a plurality of ribs  27  are formed on the outer peripheral surface of the sidewall  22  on the bottom wall  21  side with respect to the thread ridge  28 . The plurality of ribs  27  axially extend from the flange  26 . 
     As described above, the container  10  is configured so as to house any metal particles. In the case where such metal particles are electrically charged, the metal particles possibly result in electrostatic adsorption of the metal particles on the inner surface of the container  10  and the opening end surface  24  when the metal particles are taken out from the container  10 . Especially, the electrostatic adsorption of the metal particles on the opening end surface  24  causes the metal particles to be sandwiched between the lid  40  and the container body  20  when the lid  40  is again mounted to the container body  20 . This makes fastening the lid  40  difficult and deforms the metal particles. Therefore, in this embodiment, the container body  20  has the conductive property. For example, the container body  20  can be made of a material having the conductive property or the surface can be coated with a conductive material. More specifically, at least the inner surface of the container body  20  and the opening end surface  24  have the conductive property. For example, the inner surface of the container body  20  and the opening end surface  24  are coated with the conductive material. The known conductive materials are usable as this conductive material. This allows the static electricity of the metal particles to be released to the container body  20 , thereby ensuring reducing the attachment of the metal particles to the inner surface of the container body and the opening end surface  24 . 
     In this embodiment, the inner surface of the bottom wall  21  of the container body  20 , that is, the surface inside the container body  20  is formed to be flat. Furthermore, a corner portion  29 , which is formed of the bottom wall  21  and the sidewall  22 , inside the container body  20  is rounded off. That is, an inner surface of a portion where the bottom wall  21  is connected to the sidewall  22  is formed to curve. The corner portion  29  has a curvature radius of, for example, 4 mm on the cross section illustrated in  FIG. 5 . This allows the inner surface of the container body  20  to be uniformly coated with the conductive material. Specifically, for example, when a liquid conductive material is spin-coated on the inner surface of the container body  20 , since the bottom wall  21  of the container body  20  is flat, the inner surface of the bottom wall  21  is uniformly coated with the conductive material. Since the corner portion  29  is rounded off, when the conductive material is spin-coated, the conductive material can be uniformly spread along the curved corner portion  29 . The method for applying the conductive material to the inner surface of the container body  20  is not limited to the spin coating and a spray and a roll coater may be used. 
     Next, the following describes the inner plug provided with the container  10  illustrated in  FIG. 1 .  FIG. 6  is a plan view of the inner plug, and  FIG. 7  is a side view of the inner plug. An inner plug  50  is a flat plate-shaped member located inside the lid  40  illustrated in  FIG. 1  to  FIG. 4  and configured to close an opening  23  (see  FIG. 5 ) of the container body  20  together with the lid  40 . The inner plug  50  has a conductive property in one embodiment. Specifically, the inner plug  50  can be made of a material having the conductive property or the surface can be coated with a conductive material. 
     As illustrated in  FIG. 6 , the inner plug  50  includes an approximately circular-flat plate-shaped inner plug body  51  and a plurality of lock portions  52  disposed at regular intervals on the outer peripheral portion of the inner plug body  51 . The lock portions  52  are, for example, approximately rectangular flat plate-shaped projections. The lock portions  52  are disposed on the inner plug  50  by the number identical to that of threads of the screw groove  43  on the lid  40  illustrated in  FIG. 2  and other drawings. In this embodiment, the four lock portions  52  are disposed on the inner plug body  51 . The inner plug body  51  has a thickness of, for example, about 1.3 mm, and the lock portion  52  has a thickness of, for example, about 0.7 mm. Fitting the four lock portions  52  into the four-thread screw groove  43  on the lid  40  illustrated in  FIG. 2  to  FIG. 4  locks the inner plug  50  to the inside of the lid  40  to be held. 
       FIG. 8A  to  FIG. 8C  are drawings illustrating a process to hold the inner plug  50  to the lid  40 . As illustrated in  FIG. 8A , first, the inner plug  50  is positioned inside the lid  40 . At this time, the respective lock portions  52  of the inner plug  50  are inserted into respective starting ends of the screw groove  43 . Subsequently, a circumferential rotation of the inner plug  50  causes the respective lock portions  52  of the inner plug  50  to move toward the inside of the lid  40  along the screw groove  43 , that is, in a direction approaching the flat plate portion  41  (see  FIG. 8B ). Keeping the circumferential rotation of the inner plug  50  causes the inner plug  50  to move up to a position in contact with the flat portion  45   a  on the protrusion  45 . 
     Here, the inner plug  50  includes the lock portions  52  by the number identical to that of the threads of the screw groove  43  on the lid  40 , and each of the lock portions  52  is fitted into each inside of the screw groove  43 . Thus, the inner plug  50  is held into the lid  40  so as to be always approximately parallel to the flat plate portion  41  of the lid  40 . Accordingly, when the lid  40  is mounted to the container body  20 , the inner plug  50  can be uniformly brought into contact with the opening end surface  24  ( FIG. 5 ) of the container body  20 . 
     Further, the inner plug  50  in contact with the flat portion  45   a  on the protrusion  45  stops the movement of the inner plug body  51  in the direction approaching the flat plate portion  41 . Additional circumferential rotation of the inner plug  50  in this state moves only the lock portions  52  in the direction approaching the flat plate portion  41  along the screw groove  43 . Then, the lock portions  52  contact the inside (side surface portion of the screw groove  43 ) of the screw groove  43  and deform along the screw groove  43 . In other words, the inner plug body  51  contacts the flat portion  45   a  and the lock portions  52  contact the inside of the screw groove  43 . This applies a stress from the flat portion  45   a  to the inner plug body  51  in a direction from the flat plate portion  41  toward the opening of the lid  40  (lower direction in  FIG. 8A  to  FIG. 8C ) and applies a stress from the screw groove  43  to the lock portions  52  in a direction from the opening of the lid  40  toward the flat plate portion  41  (upper direction in  FIG. 8A  to  FIG. 8C ). This generates a friction between the lock portions  52  and the inside of the screw groove  43 , thus fixing the lock portions  52  of the inner plug  50  into the screw groove  43 . 
       FIG. 9  is a cross-sectional view illustrating a state of the inner plug  50  held into the lid  40 . As described above, the inner surface of the side portion  42  of the lid  40  has the gradient G 1  (see  FIG. 2 ) such that the inner diameter gradually decreases to the flat plate portion  41 . Accordingly, as indicated by the dashed line in  FIG. 9 , when the inner plug  50  is positioned near the opening of the lid  40 , a predetermined gap is present in a radial direction (right-left direction in the drawing) between the screw groove  43  and the lock portion  52  of the inner plug  50 . Meanwhile, like the inner plug  50  indicated by the solid line in  FIG. 9 , when the inner plug  50  is positioned near the protrusion  45 , the lock portion  52  of the inner plug  50  contacts a groove bottom portion of the screw groove  43  and generates a friction force between the screw groove  43  and the inner plug  50 . This fits the lock portions  52  of the inner plug  50  into the screw groove  43  to be held or fixed. 
     In this embodiment, to hold the inner plug  50  into the lid  40 , (i) the inner surface of the side portion  42  of the lid  40  has the gradient G 1  (see  FIG. 2 ) so as to gradually decrease the inner diameter toward the flat plate portion  41  and (ii) the inner plug body  51  is brought into contact with the flat portion  45   a  and the lock portions  52  are brought into contact with the inside (side surface portion of the screw groove  43 ) of the screw groove  43 . However, this should not be construed in a limiting sense. The lid  40  may be configured to have any one of the above-described features (i) and (ii). Such case also allows fixing the inner plug  50  into the screw groove  43 . Constituting the lid  40  so as to have both of the above-described features (i) and (ii) like this embodiment allows further reliably fixing the inner plug  50  into the screw groove  43 . 
       FIG. 10  is a cross-sectional side view of the container  10  where the opening  23  of the container body  20  is closed with the lid  40 .  FIG. 11  is an enlarged cross-sectional view near the protrusion  45  where the opening  23  of the container body  20  is closed with the lid  40 . As illustrated in  FIG. 10 , the lid  40  closes the container body  20  by screwing the screw groove  43  on the lid  40  with the thread ridge  28  on the container body  20 . At this time, the inner plug  50  held into the lid  40  is sandwiched between the protrusion  45  and the opening end surface  24  of the container body  20 . Further, the lid  40  is screwed into the container body  20  to apply a stress to the inner plug  50  from the flat portion  45   a  on the protrusion  45  and an inner peripheral edge  24   a  of the opening end surface  24 . This tightly closes the opening end surface  24  of the container body  20  with the inner plug  50 . 
     As illustrated in  FIG. 11 , in this embodiment, an inner periphery diameter of the flat portion  45   a  on the protrusion  45  is designed to be smaller than the inner diameter of the inner peripheral edge  24   a  of the opening end surface  24 . This applies a stress to the inner plug  50  from the flat portion  45   a  on the protrusion  45  and the inner peripheral edge  24   a  of the opening end surface  24 . Accordingly, since the stress is applied to the inner plug  50  to be lineally concentrated along the inner peripheral edge  24   a  of the opening end surface  24 , the opening end surface  24  of the container body  20  can be further tightly closed. 
     The inner plug  50  is held into the lid  40  so as to be always approximately parallel to the flat plate portion  41  of the lid  40 . Therefore, when the lid  40  is mounted to the container body  20 , the inner plug  50  can be uniformly brought into contact with the opening end surface  24  of the container body  20 , and the gap with the inner peripheral edge  24   a  of the opening end surface  24  of the container body  20  can be uniformly decreased. Accordingly, even when metal particles having a considerably small grain diameter (for example, 0.76 mm or less) are housed in the container  10 , the metal particles can be reduced to be sandwiched between the inner peripheral edge  24   a  of the container body  20  and the inner plug  50 . Eventually, the deformation of the metal particles during the conveyance of the container  10  can be reduced. 
     With the container  10  according to this embodiment, the inner plug  50  is configured so as to be held into the lid  40  with the screw groove  43  on the lid  40 . In view of this, when the container  10  is opened and closed, this configuration allows preventing the inner plug  50  from falling from the lid  40 . 
     With the container  10  according to this embodiment, the inner plug  50  has the conductive property. Accordingly, even when the metal particles housed in the container  10  are electrically charged, the metal particles do not attach to the inner plug  50 . Furthermore, the container body  20  and the lid  40  preferably have the conductive property. In this case, even if the metal particles are electrically-charged in rolling caused by, for example, an inclination of the container  10 , the metal particles are diselectrified via the inner plug  50 , the container body  20 , and the lid  40 . For the inner plug  50 , the container body  20 , and the lid  40  of this embodiment, a conductive resin such as a resin containing a carbon may be used or a conductive property may be provided by application of a conductive coating material. Accordingly, when the metal particles in the container  10  are moved to a pallet or similar member, this embodiment allows reducing the attachment of the metal particles to the container body  20 , the lid  40 , and the inner plug  50  by static electricity and their dispersion. 
     The container  10  according to this embodiment is configured such that the axial length of the container body  20  becomes larger than the diameter of the bottom wall  21 . Accordingly, the user grips the container body  20  of the container  10  with ease. Thus, the container body  20  of the container  10  is easily gripped by the user, leading to an increased area of the hand of the user in contact with the container  10 . Therefore, the static electricity on the metal particles is likely to be discharged via the hand of the user. 
     Next, the following describes the package according to this embodiment.  FIG. 12  is a drawing illustrating a state of the package before hermetic seal, and  FIG. 13  is a vertical cross-sectional view of the package after the hermetic seal. As illustrated in  FIG. 12 , a package  60  includes the containers  10  described in  FIG. 1  to  FIG. 11 , a holding member  62  to hold the container  10 , a deoxidizing and drying agent  63 , and a bag member  64  that houses the container  10 , the holding member  62 , and the deoxidizing and drying agent  63  for sealing in the hermetic seal state. 
     The holding member  62  includes a flat plate-shaped plate member  65 , receptacles  61  to receive the container  10 , and a depressed portion  66  to locate the deoxidizing and drying agent  63 . In this embodiment, the holding member  62  includes the four receptacles  61  to hold the four containers  10 . The plurality of containers  10  are each housed in the receptacle  61  on the holding member  62 , thus maintaining mutual relative positions. The depressed portion  66  is disposed at an approximately center of the four receptacles  61  such that the deoxidizing and drying agent  63  is positioned at a location separated from the respective holding members  62  housed in the receptacles  61  at approximately equal distances. 
     As illustrated in  FIG. 13 , buffering bulges  67  are formed at the respective lower portions of the receptacles  61  for reduction of an impact from outside. The impact from outside in this case is, for example, an impact due to a fall of the package  60 . 
     To pack the containers  10 , first, the metal particles such as the solder balls are put into the containers  10 . Afterwards, the containers  10  are housed in the receptacles  61  on the holding member  62 , and the deoxidizing and drying agent  63  is located at the depressed portion  66 . A pressing member or similar member that presses the deoxidizing and drying agent  63  against the depressed portion  66  may be disposed to avoid the deoxidizing and drying agent  63  to drop from the depressed portion  66 . 
     Subsequently, the containers  10 , the holding member  62 , and the deoxidizing and drying agent  63  are put in the bag member  64 . Hermetically sealing the end portion of the bag member  64  hermetically seals the containers  10 , the holding member  62 , and the deoxidizing and drying agent  63  as illustrated in  FIG. 10 . 
     The bag member  64  is made of a material impermeable to air. As a material used for the bag member  64 , a material with sufficiently low oxygen permeability and water vapor permeability is employed. The oxygen permeability preferably exhibits a daily volume of oxygen permeating a sheet of 10 ml or less per 1 m 2  of the sheet under an environment having a temperature of 23° C., a humidity of 0% and an atmospheric pressure of 1 MPa. The water vapor permeability preferably exhibits a daily volume of moisture permeating the sheet of 1 gram or less per 1 m 2  of the sheet under an environment having a temperature of 40° C. and a relative humidity of 90%. The bag member  64  can be made of, for example, an aluminum sheet material. Alternatively, the bag member  64  made of an air permeable material may be coated with an aluminum or the like so as to provide the bag member  64  with impermeability to air. 
     Further, the deoxidizing and drying agent  63  is one having a deoxidization function and absorbing moisture so as to prevent oxidization of a subject caused by oxygen and moisture. A commercially available product, for example, a RP agent (product name of a product from MITSUBISHI GAS CHEMICAL COMPANY, INC.) is usable as the deoxidizing and drying agent. 
     As described above, the lid  40  for the container  10  does not hermetically seal the internal space of the container body  20  completely. In view of this, housing the containers  10  in the bag member  64  together with the deoxidizing and drying agent  63  absorbs oxygen and moisture in an internal atmosphere of the containers  10  by the deoxidizing and drying agent  63 , thus ensuring preventing the oxidation of the metal particles. 
     The number of containers  10  held by the holding member  62  is not limited to four. The increase and decrease in the number of receptacles  61  can appropriately increase and decrease the number of containers  10  capable of being held by the holding member  62 . In the case where the number of containers  10  held by the holding member  62  is further increased, the number of deoxidizing and drying agents  63  may be increased. 
     When the containers  10  are used, the bag member  64  of the package  60  illustrated in  FIG. 13  is partially broken, and the holding member  62  is taken out from the bag member  64 . The lids  40  for the containers  10  are removed and the metal particles in the containers  10  are supplied on a pallet. With the unused containers  10  housed in the holding member  62 , the unused containers  10  are returned into the bag member  64  together with a new unused deoxidizing and drying agent  63 . The broken part of the bag member  64  is closed by applying a reliable seal such as thermocompression bonding to avoid ingress of outside air. In the case where not all of the metal particles in the single container  10  are consumed, the container  10  is closed by the lid  40 , returned into the holding member  62 , and then housed into the bag member  64 . Thus, the bag member  64  is resealed. 
     The embodiments of the present invention have been described above in order to facilitate understanding of the present invention without limiting the present invention. The present invention can be changed or improved without departing from the gist thereof, and of course, the equivalents of the present invention are included in the present invention. It is possible to arbitrarily combine or omit respective components according to claims and description in a range in which at least a part of the above-described problems can be solved, or a range in which at least a part of the effects can be exhibited. 
     REFERENCE SIGNS LIST 
     
         
         
           
               10  . . . container 
               20  . . . container body 
               21  . . . bottom wall 
               22  . . . sidewall 
               23  . . . opening 
               24  . . . opening end surface 
               24   a  . . . inner peripheral edge 
               28  . . . thread ridge 
               29  . . . corner portion 
               40  . . . lid 
               41  . . . flat plate portion 
               42  . . . side portion 
               43  . . . screw groove 
               45  . . . protrusion 
               45   a  . . . flat portion 
               50  . . . inner plug 
               51  . . . inner plug body 
               52  . . . lock portion 
               60  . . . package 
               61  . . . receptacle 
               62  . . . holding member 
               63  . . . deoxidizing and drying agent 
               64  . . . bag member 
             G 1  . . . gradient