JP2010052781A - Storing container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a storing container which can restrain contamination of an article and can reduce moisture release from the container body or a lid and can assure sufficient mechanical strength. <P>SOLUTION: The storing container includes a front open box type container body 1, in which two or more semiconductor wafers are stored standing in a row, and the lid 20 which opens and closes the opened front face of the container body 1 attachably and detachably and the container body 1 is formed of a molding material containing a resin mixture by an injection molding. The resin mixture of the molding material is adjusted by mixing a resin with a comparatively high melt viscosity and a resin with a comparatively low melt viscosity and the resin with the comparatively low melt viscosity is a resin with a low water absorption and a low moisture permeability and the inner and outer surface of the peripheral wall 3 of the container body 1 is formed of the resin with the comparatively low melt viscosity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a storage container for storing a substrate represented by a semiconductor wafer.

  A conventional storage container for storing semiconductor wafers is not shown, but is, for example, a front open box type container main body that stores a thin semiconductor wafer of φ300 mm, and a detachable that opens and closes the open front portion of the container main body via a gasket. And a lid body.

  The container body is injection molded using a molding material containing a thermoplastic resin such as polypropylene, polycarbonate resin, polybutylene terephthalate, polymethyl methacrylate, polystyrene, acrylonitrile butadiene styrene copolymer resin, etc. Align and store side by side.

  By the way, in order to prevent contamination of the semiconductor wafer stored in the container body, the storage container can reduce as much as possible metal components, free ions, outgas, and other impurities contained or remaining in the resin constituting the container body. It is desired. However, it is technically and costly to completely remove the components contained in or remaining in the resin constituting the container body.

  On the other hand, the amount of moisture (humidity) in the container body can be raised as a cause of the residue and impurities contaminating the surface of the semiconductor wafer. A method is adopted in which the semiconductor wafer is housed in the dry dry container body. However, even if the inside of the container body is completely dry, the humidity inside the container body increases with time due to moisture released from the resin constituting the container body or permeated from the outside of the container body. Small dew condensation occurs on the surface of the semiconductor wafer, and impurities adhere to it.

Then, the method of using the molding material with low water absorption and moisture permeability as a molding material which comprises a container main body is proposed. However, when such a molding material is used, the strength of the container body, particularly the drop impact resistance, is insufficient, which may cause damage to the container body or the semiconductor wafer during transportation or transportation.
In view of the above, a method of maintaining the strength of the container body by covering the surface of the container body with a barrier film regardless of the molding material of the container body has been proposed (see Patent Document 1).
JP 2005-521236 A

  However, when adopting a method of coating the surface of the container body with a barrier film, the strength of the container body can be maintained, but the film is uniformly formed on the surface of the container body having a complicated uneven shape, and There is a problem that it is difficult to apply stably, and the cost of molding the container body is increased.

  The present invention has been made in view of the above, and provides a storage container that can suppress contamination of articles, reduce the amount of moisture released from the container body and the lid, and can ensure sufficient mechanical strength. It is an object.

In order to solve the above problems, the present invention includes a container main body for storing articles and a lid for opening and closing the opening of the container main body, and at least the container main body of the container main body and the lid includes a resin mixture. Molded with the molding material of
A resin mixture of a molding material is prepared by mixing a resin having a relatively high melt viscosity and a resin having a low melt viscosity, and a resin having a relatively low melt viscosity is used as a resin having low water absorption and low moisture permeability. Is characterized in that at least the inner surface of the container body facing the article is formed of a relatively low resin.

In addition, the container main body which accommodates a board | substrate, and the detachable cover body fitted by the opening part of this container main body can be provided.
Moreover, the relative level difference of melt viscosity can be 0.2 * 10 < ² > -1.0 * 10 < ⁷ > Pa * s.
Further, the relative viscosity difference between the resin having a relatively high melt viscosity and the resin having a low melt viscosity can be set to 1 to 100 in terms of MFR value.

The resin having a relatively low melt viscosity may be a polyethylene resin, a polypropylene resin, a cycloolefin polymer, or a terminal long-chain alkyl group-introduced polycarbonate resin.
Further, the peripheral wall of the container body is formed of a high-viscosity resin layer formed of a resin having a relatively high melt viscosity, and a low-viscosity resin layer formed of a resin having a relatively low melt viscosity and facing the high-viscosity resin layer. A multilayer structure including a gradient resin layer interposed between the high-viscosity resin layer and the low-viscosity resin layer is preferable.

  Here, the articles in the claims include at least the necessary number of semiconductor wafers, photomask materials, lead frames, glass substrates, electronic parts, device parts, miscellaneous goods of φ200, 300, and 450 mm. Moreover, although a container main body and a lid body may shape | mold a container main body with the molding material containing a resin mixture, you may shape | mold a lid body also with the molding material containing a resin mixture. The container body may be a front open box type, a top open box type, a bottom open box type, transparent, opaque, or translucent.

  The molding material may be a material composed only of the resin mixture, but may appropriately contain various fillers composed of carbon, carbon fiber, metal fiber, conductive polymer, antistatic agent, flame retardant, etc. in addition to the resin mixture. .

  According to the present invention, a resin having a relatively high melt viscosity in the resin mixture forms at least the container body to ensure its strength and rigidity. In addition, a resin having a relatively low melt viscosity and a low water absorption rate and low moisture permeability faces the article as at least the inner surface of the container body to prevent moisture release and permeation to the container body, and the humidity in the container body is maintained over time. To prevent the rise.

  According to the present invention, a resin mixture of a molding material is prepared by mixing a resin having a relatively high melt viscosity and a resin having a low melt viscosity, and the resin having a relatively low melt viscosity has a low water absorption and low moisture permeability. Since the resin and the resin having a relatively low melt viscosity form an inner surface facing at least the article of the container main body, the contamination of the article is suppressed, and the amount of moisture released with respect to the container main body and the lid is reduced. There is an effect that sufficient mechanical strength can be secured.

  Hereinafter, a preferred embodiment of a storage container according to the present invention will be described with reference to the drawings. The storage container in this embodiment is a front open for storing a plurality of semiconductor wafers W as shown in FIGS. A box-type container main body 1 and a lid 20 that removably opens and closes the opened front portion of the container main body 1 through a gasket. The container main body 1 is injection-molded with a molding material containing a resin mixture. The peripheral wall 3 of the main body 1 is formed by a high viscosity resin layer 3a, a low viscosity resin layer 3b, and an inclined resin layer 3c.

  As shown in FIG. 2, the semiconductor wafer W is made of, for example, a thin silicon wafer having a diameter of 300 mm, and a notch for alignment and identification (not shown) is notched in the peripheral portion. Aligned and stored.

  As shown in FIG. 1 and FIG. 2, the container body 1 is formed into an opaque front open box type, and a pair of left and right teeth 2 that horizontally support the semiconductor wafer W are arranged side by side in the vertical direction on both sides inside the container body 1. It is mounted on a semiconductor processing device or a gas replacement device in a state where the horizontally long front portion that is open is directed horizontally, or is washed with a washing liquid in a washing tank.

  A bottom plate 4 which is the peripheral wall 3 of the container body 1 is mounted with a substantially Y-shaped base plate 5, and the storage container, specifically, the container body 1 is positioned on the front side and the rear center of the base plate 5. Each positioning tool 6 is screwed. A plurality of identification holes are drilled in the rear part of the base plate 5, and a detachable information identification pad 7 (not shown) is selectively inserted into the plurality of identification holes, so that the type of the storage container and the number of semiconductor wafers W are increased. Are identified by a semiconductor processing apparatus or the like.

  A top flange 9 for conveyance gripped by a ceiling conveyance mechanism in a factory is horizontally screwed to the top plate 8 that is the peripheral wall 3 of the container body 1. In addition, a transparent viewing window is formed vertically on the back wall 10 which is the peripheral wall 3 of the container body 1 by a two-color molding method or the like, and the inside of the container body 1 is visually observed from the outside through this viewing window. Be grasped. A rear retainer 11 that holds the rear end of the peripheral edge of the semiconductor wafer W is mounted on the inner surface of the back wall 10.

  On the surfaces of both side walls 12 that are the peripheral walls 3 of the container main body 1, grip handles 13 that enable a gripping operation are respectively mounted. Further, the front portion of the container body 1 is formed with a rim flange 14 projecting outward at the periphery, and a detachable lid 20 is fitted into the rim flange 14 by a lid opening / closing device.

  The lid 20 is injection-molded with a molding material containing a predetermined resin. Examples of the predetermined resin of the molding material include polycarbonate resin, polyether ether ketone, polyether imide, and cyclic olefin resin, which are excellent in mechanical properties and heat resistance. Carbon, a conductive polymer, an antistatic agent and the like are selectively added to the molding material as necessary.

  As shown in FIG. 1, the lid 20 includes a horizontally long casing 21 that fits into the opened rim flange 14 of the container body 1, and a surface plate that covers the opened surface (front) of the casing 21. And a locking mechanism is selectively interposed between the housing 21 and the surface plate. The housing 21 is basically formed in a shallow bottom cross-sectional plate shape having a frame-shaped peripheral wall, and a front retainer 22 that elastically holds the front end of the peripheral edge of the semiconductor wafer W on both sides of the back surface. Are detachably mounted.

  Rectangular locking pieces 23 that can be rotated in the front-rear direction are pivotally supported on both side portions of the casing 21, and the notches of the pair of locking pieces 23 extend from both side portions of the rim flange 14 of the container body 1. Each of the protruding locking projections 15 is fitted and locked.

  By the way, the resin mixture of the molding material which molds the container body 1 is prepared by mixing a resin having a relatively high melt viscosity and a low resin measured under the same conditions. The resin has a low water absorption and low moisture permeability, and forms the peripheral wall 3 of the container body 1, in other words, the bottom plate 4, the top plate 8, the back wall 10, and the side wall 12 of the container body 1.

  Examples of the resin mixture include polyethylene resin, polypropylene resin, polycarbonate resin, cycloolefin polymer resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyamide resin, polyvinyl chloride resin, ethylene vinyl alcohol copolymer, acrylonitrile styrene copolymer Polymer, Polyacetal resin, Modified polyphenylene ether resin, Polysulfone resin, Polyethersulfone resin, Polyphenylene sulfide resin, Polyarylate resin, Thermoplastic polyimide resin, Polyetheretherketone resin, Liquid crystal polymer resin, Thermoplastic fluororesin, Syndiotactic Polystyrene resin, terminal long-chain alkyl group-introduced polycarbonate resin, polylactic acid-based biodegradable resin, aliphatic polyester-based biodegradable resin,肪芳 aromatic copolyester-based biodegradable resin and the like. These resins are arbitrarily selected so that the melt viscosity has a relatively high and low relationship, and the relatively low viscosity resin has low water absorption and low moisture permeability.

  Specifically, as a resin having a relatively high melt viscosity, polycarbonate resin, cycloolefin polymer, polyphenylene sulfide, polypropylene resin, terminal long chain alkyl group-introduced polycarbonate, liquid crystal polymer, syndiotactic polystyrene, modified polyphenylene ether resin These resins are appropriately selected.

Examples of relatively low melt viscosity, low water absorption, and low moisture permeability resins include polyethylene resins, polypropylene resins, cycloolefin polymers, and terminal long-chain alkyl group-introduced polycarbonate resins. Selected. Specifically, it is a resin having a water absorption rate of 0.1% or less and a moisture permeability of 3 g / m ² · 24 h or less. The water absorption rate is evaluated by, for example, ASTM D 570.

  The resin mixture is preferably used by kneading a resin to be used in advance with a Henschel mixer, a Banbury mixer, a pressure kneader, a biaxial kneader, or the like, in an appropriate dispersion state. This dispersion state is selected by appropriately adjusting in consideration of the difference in relative viscosity of the resin used and the thickness of the low-viscosity resin layer 3b of the injection-molded container body 1.

  For the measurement of the relative viscosity, the value of melt viscosity obtained by MFR, MVR, capillary rheometer, or Koka flow tester can be used. Among these, MFR is beneficial. It is also possible to set a relative viscosity difference based on a value measured with a capillary rheometer in relation to the measurement temperature and the shear rate.

The relative viscosity difference is in the range of 1 to 100, preferably 3 to 50 in the case of the MFR value. The relative difference in melt viscosity is 0.2 × 10 ^{2 to} 1.0 × 10 ⁷ Pa · s in the range of the difference in melt viscosity obtained by measurement under the same measurement conditions, preferably 1. It is preferable that it is in the range of 0 × 10 ^{2 to} 1.0 ⁵ Pa · s.

  As shown in FIG. 3, the peripheral wall 3 of the container body 1 is formed of a high-viscosity resin layer 3a of the peripheral wall body formed of a resin having a relatively high melt viscosity and a resin having a relatively low melt viscosity. A pair of low-viscosity resin layers 3b facing the inner and outer surfaces of the viscosity resin layer 3a, and a pair of inclined resin layers 3c interposed between the high-viscosity resin layer 3a and the pair of low-viscosity resin layers 3b. The low-viscosity resin layer 3b forms inner and outer surfaces (also front and back surfaces) of the peripheral wall 3 as a skin layer.

  That is, the peripheral wall 3 of the container body 1 has a relatively high-viscosity resin as a high-viscosity resin layer 3a at the center, and the ratio of the relatively high-viscosity resin to the low-viscosity resin toward the inner and outer surfaces. Is formed, the exposed inner and outer surfaces are formed in the low-viscosity resin layer 3b with the lowest-viscosity resin, and the inner low-viscosity resin layer 3b faces the semiconductor wafer W. .

  The wall thickness of the peripheral wall 3 of the container body 1 is in the range of 2.0 mm to 10.0 mm, preferably 3.0 mm to 7.0 mm, taking into account the mechanical strength of the container body 1 and the weight during transportation. This is because if the thickness is less than 2.0 mm, the strength of the container body 1 is insufficient, and there is a risk of damage due to an impact at the time of dropping. On the other hand, if it exceeds 10.0 mm, the mold This is because the low-viscosity resin is difficult to flow to the mold surface during the injection molding using the resin, it is difficult to obtain the predetermined low-viscosity resin layer 3b, and the weight of the container body 1 becomes too heavy, so that the transport workability is reduced. is there.

  As described above, the thickness of the low-viscosity resin layer 3b is 1 μm or more, preferably 10 μm or more in consideration of prevention of humidity change in the container body 1, mechanical strength of the container body 1, peeling of the low-viscosity resin layer 3b, and the like. More preferably, it is 50 μm or more. This is because when the thickness is less than 1 μm, it is not possible to suppress the release of moisture present in the relatively high viscosity resin into the container body 1. Moreover, because the low-viscosity resin layer 3b is insufficient in strength, it is likely to be peeled off from the container body 1 and worn due to friction. The thickness of the low-viscosity resin layer 3b can be adjusted by the resin viscosity difference in the resin mixture, the molding temperature at the time of injection molding, the injection pressure, the mold cavity shape, and the like.

  In the above, when manufacturing the container main body 1, what is necessary is just to inject and shape | mold the molding material containing a resin mixture to a metal mold | die. At this time, from the relationship between the molding pressure and the resin flow, a relatively low viscosity resin exists in a large amount on the surface side of the mold, that is, on the inner and outer surface sides of the peripheral wall 3 of the container body 1. On the other hand, the relatively high-viscosity resin occupies the inside of the peripheral wall 3 of the container body 1, and the ratio gradually decreases toward the inner and outer surface sides of the peripheral wall 3. As a result, the inner peripheral surface 3 of the molded container body 1 is made of a relatively high viscosity resin, and the entire inner and outer surfaces are made of a relatively low viscosity, particularly the lowest viscosity resin in the resin mixture. The

  According to the said structure, since the resin which comprises the inner and outer surface of the container main body 1 is a low water absorption rate and low moisture permeability, the humidity rise in the container main body 1 and the inside of the container main body 1 with respect to the atmosphere where the container main body 1 is set | placed Therefore, it is possible to prevent the contamination of the semiconductor wafer W. Further, unlike the conventional case, the molding material of the container body 1 is ignored and the surface of the container body 1 is not covered with the barrier film, so that there is no possibility of increasing the molding cost of the container body 1.

  The container body 1 is required to have mechanical strength (impact strength, etc.) that does not cause a problem in use in transporting and transporting the semiconductor wafer W. For example, a polycarbonate resin may be used as a relatively high viscosity resin. Is used, the peripheral wall 3 of the container body 1 is made of polycarbonate resin, so that sufficient mechanical strength can be obtained. Furthermore, if a resin having a relatively low viscosity is mixed with a polycarbonate resin and injection-molded, the inner and outer surfaces of the container body 1 are covered with a resin having a low water absorption rate and a low moisture permeability, so that sufficient mechanical strength and A container body 1 capable of suppressing an increase in internal humidity can be obtained.

  In the above embodiment, a resin having a relatively high melt viscosity and a resin having a low melt viscosity are simply shown. However, a plurality of resins having a relatively high melt viscosity may be used, or a plurality of resins having a relatively low melt viscosity may be used. Also good. Alternatively, the rear retainer 11, the casing 21 of the lid 20, and the front retainer 22 may be formed by injection molding with a resin mixture-containing molding material to form the high viscosity resin layer 3a, the low viscosity resin layer 3b, and the inclined resin layer 3c. good.

Examples of the storage container according to the present invention will be described below, but the storage container according to the present invention is not limited to the following examples.
First, a resin A having a relatively high melt viscosity measured under the same conditions and a resin B having a low melt viscosity are combined at the composition and blending ratio shown in Table 1, and mixed with a twin-screw extruder to prepare a resin mixture as a molding material. The resin mixture was pelletized and injected into a mold, and the container body of the storage container for storing the semiconductor wafer shown in FIG. 1 was injection molded.

  As resin A having relatively high melt viscosity, as shown in Table 1, (1) Polycarbonate: Novalex 7022R (trade name: manufactured by Mitsubishi Engineering Plastics), (4) Polypropylene-2: Novatec PP MA3H ( (Trade name: manufactured by Nippon Polypro Co., Ltd.), (5) cycloolefin polymer-2: ZEONOR 1020R (trade name: manufactured by ZEON CORPORATION) was selectively used.

  As resin B having relatively low melt viscosity, as shown in Table 1, (2) cycloolefin polymer-1: Zeonore 1060R (trade name: manufactured by Nippon Zeon), (3) polypropylene-1: Novatec PP MA1B (Trade name: manufactured by Nippon Polypro Co., Ltd.) was used.

  The MFR value, water absorption rate, and moisture permeability of the resins A and B having relatively high melt viscosities were measured in advance and summarized in Table 2.

  After the container body of the storage container was injection-molded, the inside of the container body was replaced with pure nitrogen gas (purity 99.999% or more) and sealed with the lid shown in FIG. At this time, a temperature / humidity measurement data logger was placed in the container body, and the time-dependent changes in temperature and humidity in the container body after nitrogen gas replacement were measured.

  From the above examples, it was found that the container body of the storage container is effective in preventing contamination of the semiconductor wafer because it has sufficient mechanical strength and extremely little moisture is released to the inside.

It is a perspective explanatory view showing an embodiment of a storage container concerning the present invention typically. It is a section explanatory view showing typically a container main part in an embodiment of a storage container concerning the present invention. It is a principal part expanded sectional view which expands and shows the III section of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container body 3 Perimeter wall 3a High-viscosity resin layer 3b Low-viscosity resin layer 3c Inclined resin layer 4 Bottom plate 8 Top plate 10 Back wall 12 Side wall 20 Lid 21 Case W Semiconductor wafer (article)

Claims (2)

A container body that contains an article, and a lid body that opens and closes an opening of the container body, and at least the container body of the container body and the lid body is molded from a molding material containing a resin mixture. ,
A resin mixture of a molding material is prepared by mixing a resin having a relatively high melt viscosity and a resin having a low melt viscosity, and a resin having a relatively low melt viscosity is used as a resin having low water absorption and low moisture permeability. A storage container, wherein at least an inner surface of the container body facing an article is formed of a resin having a relatively low value.   The storage container of Claim 1 provided with the container main body which accommodates a board | substrate, and the detachable cover body fitted by the opening part of this container main body.

Images