Packaging of mirror-finished objects and packaging methods for mirror-finished objects

Abstract

The packaging body (30, 31) of the mirror-finished body of the present invention is a packaging body in which a mirror-finished body (10) having a mirror-finished surface (11) is sealed in a vacuum state in a bag (20, 21) made of resin film. The resin film constituting the bag (20, 21) is in contact with the mirror-finished surface (11), and the crystallinity of the resin film is 40% or more and 60% or less, preferably 44% or more and 54% or less.

Description

Technical Field

[0001] This invention relates to a packaging body containing a mirror-finished object and a packaging method for the packaging body, wherein the mirror-finished object is a high-cleanliness material, such as an electrode plate used in a plasma etching machine or a sputtering target for semiconductors. This application claims priority to Japan Patent Application No. 2021-014909, filed on February 2, 2021, the contents of which are incorporated herein by reference. Prior Technology

[0002] Previously, electrode plates used in plasma etching machines were known. However, problems arise when such electrode plates are used on mirror-finished surfaces (mirror-finished surfaces) with foreign matter adhering to them; therefore, the mirror-finished surface must be cleaned before use to remove foreign matter. To suppress the adhesion of such foreign matter, the mirror-finished body is handled by sealing it in a bag under vacuum. However, even when handling the mirror-finished body in a sealed state under vacuum, the generation of foreign matter cannot be completely suppressed; therefore, further solutions are being sought.

[0003] For example, although the technical fields are different, the following efforts are being made for semiconductor wafers (hereinafter referred to as wafers) with mirror-finished surfaces. For wafer handling, multiple wafers are stored in a plastic container, and multiple such containers are packed into a box with cushioning material between each container before being moved. Therefore, the packaging process is complex and requires multiple containers, resulting in significant cost waste. Furthermore, during unpacking, ultrapure water is needed to remove dust and contaminants that adhered to the containers during these steps.

[0004] To address these challenges, packaging methods, such as those described in Patent Documents 1 and 2, involve alternately stacking semiconductor wafers and ice plates made of ultrapure water (DIW) in a container. Patent Document 1 describes a packaging method in which multiple semiconductor wafers are frozen in ultrapure water (pure water that has undergone only ion exchange and has been further purified by reverse osmosis or similar methods) at predetermined intervals before being stored in a container. Furthermore, Patent Document 2 describes a method in which polyethylene glycol (WAX) is coated onto the entire surface of a mirror-polished semiconductor wafer. [Previous Technical Documents] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 4-128173(A) [Patent Document 2] Japanese Patent Application Publication No. 6-204315(A) Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] In the methods described in Patent Documents 1 and 2 above, the packaging methods are complex and difficult to unpack. Therefore, as a packaging method for mirror-finished objects, the mirror-finished object is usually sealed in a vacuum and packaged in a bag. However, when the bag is made of resin film, when the packaged object is opened, small foreign objects such as stains, cloudiness, and granular white spots can be seen on the mirror-finished surface. Therefore, there is a need for a packaging method for mirror-finished objects that can suppress the generation of small foreign objects on the mirror-finished surface of the object, even when using simple packaging methods such as resin film packaging.

[0008] The present invention was made in view of the following circumstances, and its purpose is to provide a packaging body and a packaging method for a mirror-finished body, which can suppress the generation of minute foreign objects on the mirror-finished surface of the mirror-finished body. [Methods for solving the problem]

[0009] The packaging of the mirror-finished body of the present invention is a packaging body in which the mirror-finished body having a mirror-finished surface is sealed in a bag made of resin film under vacuum. The resin film constituting the bag is in contact with the mirror-finished surface, and the crystallinity of the resin film is 40% or more and 60% or less.

[0010] When the crystallinity of the resin film of the present invention is less than 40%, the resin film in contact with the mirror-finished surface is too soft, and amorphous molecules (e.g., PE molecules when the resin film is made of polyethylene) adhere to the mirror-finished surface and become tiny foreign matter. On the other hand, if the crystallinity of the resin film exceeds 60%, the resin film in contact with the mirror becomes hard and brittle, and when the mirror-finished object is stored in a bag, some of it will peel off and become tiny foreign matter if it comes into contact with the resin film. On the other hand, in the present invention, by setting the crystallinity of the resin film within an appropriate range of 40% or more and 60% or less, the generation of tiny foreign matter from the resin film in contact with the mirror-finished surface of the mirror-finished object can be suppressed.

[0011] The preferred embodiment of the packaging body of the mirror-finished body of the present invention preferably has a crystallinity of 44% or more and 54% or less for the aforementioned resin film.

[0012] The packaging body of the mirror-finished body of the present invention is a packaging body in which the mirror-finished body having a mirror-finished surface is sealed in a bag under vacuum. An inner resin film covering the mirror-finished surface is provided between the mirror-finished surface and the inner surface of the bag, and the periphery of the inner resin film is arranged to protrude from the periphery of the mirror-finished body.

[0013] In this invention, when a mirror-finished body, in which the mirror-finished surface is covered by an inner resin film, is housed within a bag, the periphery of the inner resin film is positioned to protrude from the periphery of the mirror-finished body. Therefore, direct contact between the edge of the mirror-finished body and the bag body, preventing the generation of minute foreign objects, can be prevented. Furthermore, since the mirror-finished body is protected by a two-layer structure of the bag body and the inner resin film, the mirror-finished body can be protected more reliably.

[0014] In a preferred embodiment of the packaging body of the mirror-finished body of the present invention, the first coefficient of friction between the surface of the inner resin film on the bag side and the inner surface of the bag is smaller than the second coefficient of friction between the mirror-finished surface and the surface of the inner resin film that contacts the mirror-finished surface.

[0015] In the above-described state, since the second coefficient of friction is greater than the first coefficient of friction, when the mirror-finished body, whose mirror-finished surface is covered by the inner resin film, is placed inside the bag, and when the bag is evacuated, there is no relative movement between the mirror-finished surface and the inner resin film; instead, there is relative movement between the inner resin film and the inner surface of the bag. That is, since the mirror-finished body and the inner resin film do not rub against each other, the generation of minute foreign objects caused by friction between the mirror-finished body and the inner resin film can be suppressed. If the first coefficient of friction is greater than the second coefficient of friction, the inner resin film and the inner surface of the bag will be in close contact during storage or vacuuming. Displacement will occur between the mirror-finished body and the inner resin film. Due to the friction between the mirror-finished surface and the inner resin film, tiny foreign objects may be generated.

[0016] The preferred form of the packaging body of the mirror-finished body of the present invention is that the ratio of the aforementioned second coefficient of friction to the aforementioned first coefficient of friction is 1.2 or more. In the above-mentioned state, since the inner resin film slides more easily with the bag body than the inner resin film slides with the mirror-finished surface, the generation of tiny foreign objects caused by the friction between the mirror-finished body and the inner resin film during storage or vacuuming can be reliably suppressed.

[0017] The preferred form of the packaging body of the mirror-finished body of the present invention is that the crystallinity of the aforementioned inner resin film is 40% or more and 60% or less. In the above-mentioned state, the crystallinity of the inner resin film is set to an appropriate range of 40% or more and 60% or less, so that the generation of minute foreign matter from the inner resin film in contact with the mirror surface of the mirror-finished body can be suppressed.

[0018] The packaging method of the mirror-finished body of the present invention involves placing the mirror-finished body having a mirror-finished surface into a bag made of a resin film with a crystallinity of 40% or more and 60% or less, and then vacuuming and sealing the bag while the resin film constituting the bag is in contact with the mirror-finished surface.

[0019] The packaging method of the mirror-finished body of the present invention involves placing the mirror-finished body with the aforementioned mirror-finished surface covered by an inner resin film inside a bag and sealing it. [Invention Effects]

[0020] According to the present invention, a simple method can be used to suppress the generation of minute foreign objects on the mirror-finished surface of a mirror-finished body. [Simple Explanation of the Diagram]

[0021] [Figure 1] shows a top view of the packaging body of the mirror-finished body according to the first embodiment of the present invention. [Figure 2] shows a perspective view of the mirror-finished body of the first embodiment described above. [Figure 3] is a schematic diagram showing the packaging method of the mirror-finished body according to the first embodiment described above. [Figure 4] shows a top view of the packaging body of the mirror-finished body according to the second embodiment of the present invention. [Figure 5] is a schematic diagram showing the state in which the inner resin film is configured in the packaging method of the mirror-finished body according to the second embodiment described above. [Figure 6] shows a schematic diagram of the state in which the mirror-finished body, which is held by the inner resin film, is housed in the bag in the packaging method of the mirror-finished body of the second embodiment described above. [Figure 7] shows the friction range of the silicon plate when the resin film 2 is rubbed from above the resin film 1. [Figure 8] shows an image of the aforementioned area of ​​a silicon board with resin film 2 rubbed without resin film 1. [Figure 9] shows the detection conditions for stains and particles. Implementation

[0022] Hereinafter, various embodiments of the packaging body and packaging method of the mirror-finished body of the present invention will be described using drawings.

[0023] [First Implementation Form] As shown in Figure 1, the packaging body 30 (hereinafter referred to as packaging body 30) of the mirror-finished body 10 in this embodiment is a packaging body in which the mirror-finished body 10, having a mirror-finished surface 11, is sealed in a bag 20 made of resin film under vacuum. The mirror-finished body 10, for example, is an electrode plate for a plasma etching machine formed of Si (silicon) or an intermetallic compound or ceramic, as shown in Figure 2, and is formed in a circular plate shape. The mirror-finished surface 11 is formed on both the surface side and the back side of the mirror-finished body 10. For example, the diameter of the mirror-finished body 10 is set to 203mm~530mm, the thickness is set to 3mm~19mm, and the arithmetic mean roughness Ra of the mirror-finished surface 11 is set to 0.01~0.2. The mirror-finished body 10 can be either a circular plate or a rectangular plate, as long as it is plate-shaped. When the mirror-finished body is a rectangular plate, for example, the side length of the mirror-finished body 10 is set to 50mm~500mm, the thickness is set to 3mm~19mm, and the arithmetic mean roughness Ra of the mirror-finished surface 11 is set to 0.01 to 0.2.

[0024] As shown in Figure 1, the bag body 20 is formed to be larger than the mirror-finished surface 11 of the mirror-finished body 10 when viewed from above, and is sealed while the mirror-finished body 10 is housed inside. The resin film constituting this bag body 20 is made of, for example, polyethylene. In this case, it is preferable to use an additive-free resin that does not contain additives such as antioxidants or lubricants. In addition, the resin film constituting the bag body 20 is formed into a film shape by blow molding or the like. For example, the planar dimensions of the bag body 20 are 100mm~700mm×150mm~800mm, and the thickness is 70μm~130μmmm.

[0025] Furthermore, the crystallinity of the resin film constituting the bag body 20 is set to be 40% or more and 60% or less. This crystallinity is the ratio of crystalline portions and is also a measure of the physical properties of the resin film, such as mechanical strength, density, heat resistance, and transparency. In this embodiment, the crystallinity of the resin film constituting the bag body 20 is set to an appropriate range of 40% or more and 60% or less. Preferably, this crystallinity is 44% or more and 54% or less. Furthermore, it is more preferable that the crystallinity of the resin film is 45% or more and 51% or less. If the crystallinity of the resin film constituting the bag body 20 is less than 40%, the resin film in contact with the mirror-finished surface 11 will be too soft, and amorphous PE molecules will adhere to the mirror-finished surface 11 and become tiny foreign objects. On the other hand, when the crystallinity of the resin film exceeds 60%, the resin film becomes hard and brittle, and a portion of the resin film will peel off during friction, becoming tiny foreign objects.

[0026] Packaging methods for mirror-finished products The packaging body 30 for the mirror-finished body 10 is a bag 20 made of a resin film with a crystallinity of 40% to 60%. The mirror-finished body 10 is placed inside the bag and sealed to complete the packaging. Specifically, as shown in Figure 3, an opening is provided on the bag 20, and the mirror-finished body 10 is placed through this opening. At this time, if the edge of the mirror-finished body 10 comes into contact with the inner surface of the bag 20, tiny foreign objects may be generated. Therefore, it is placed inside the bag 20 in a way that minimizes contact with the inner surface of the bag 20. Then, the air inside the bag 20 is extracted by a vacuum packaging device, and the bag 20 is sealed. In this way, the mirror-finished body 10 is packaged in the bag 20 to form the packaging body 30 for the mirror-finished body 10.

[0027] In the packaging body 30 of this embodiment, since the crystallinity of the resin film forming the bag body 20 is set in an appropriate range of 40% or more and 60% or less, the generation of minute foreign matter originating from the resin film in contact with the mirror-finished surface 11 of the mirror-finished body 10 can be suppressed. Furthermore, the packaging body 30 of this embodiment can suppress the generation of minute foreign matter simply by adjusting the crystallinity of the resin film constituting the bag body 20, thereby reducing packaging costs. For example, when the mirror-finished body 10 is an electrode plate of a plasma etching machine or a sputtering target, it is usually removed from the bag and placed in a vacuum chamber. After the vacuum is exhausted, a voltage is applied to the mirror-finished body 10 to generate plasma. At this time, if a tiny foreign object adheres to the mirror-finished surface 11, an abnormal discharge occurs starting from that tiny foreign object, and the foreign object is scattered onto the processing substrate of the plasma etching machine or splashed onto the film-forming substrate of the sputtering target. On the other hand, in this embodiment, since the generation of tiny foreign objects on the mirror-finished surface 11 of the mirror-finished body 10 can be suppressed, the abnormal discharge caused by the tiny foreign object in subsequent processes can be suppressed, and the scattering of foreign objects onto the processing substrate or the film-forming substrate can be suppressed.

[0028] [Second Implementation Form] Next, the packaging body of the mirror-finished body of the second embodiment will be described with reference to the diagram. In the following description, the same reference numerals are added to the components that are the same as or substantially the same as those in the first embodiment, and the descriptions are omitted or simplified. As shown in Figure 4, the packaging body 31 (hereinafter referred to as packaging body 31) of the mirror-finished body 10 in this embodiment is a packaging body in which the mirror-finished body 10 with a mirror-finished surface 11 is sealed in a vacuum state inside the bag body 21, and an inner resin film 40 is provided between the mirror-finished surface 11 of the mirror-finished body 10 and the bag body 21.

[0029] As shown in Figure 4, the bag body 21 is formed to be larger than the mirror-finished surface 11 of the mirror-finished body 10 or the inner resin film 40 when viewed from above, and is sealed while the mirror-finished body 10 and the inner resin film 40 are housed inside. In this embodiment, since the inner resin film 40 is provided, the bag body 21 can be formed of a resin film such as polyethylene as in the first embodiment, or it can be formed of other materials. The planar dimensions of the bag body 21 are, for example, 100mm~700mm × 150mm~800mm, and the thickness is 70μm~130μm.

[0030] As shown in Figure 4, the inner resin film 40 housed within the bag body 21 and the mirror-finished body 10 are both formed into a circular shape slightly larger than the mirror-finished surface 11 of the mirror-finished body 10 when viewed from above, and cover the entire area of ​​the mirror-finished surface 11 of the mirror-finished body 10. Furthermore, since the bag body 21 is sealed under vacuum, the inner resin film 40 is disposed within the bag body 21 in contact with both the mirror-finished surface 11 and the inner surface of the bag body 21. For this inner resin film 40, it is preferable to use an additive-free resin made of the same material as the bag body 21 (e.g., polypropylene) and free of additives such as antioxidants or lubricants. Moreover, the inner resin film 40 is formed into a film shape by blow molding or the like.

[0031] Furthermore, the diameter of the inner resin film 40 is slightly larger than the diameter of the mirror-finished body 10 (203 mm to 530 mm), for example, 204.5 mm to 539.5 mm, and the thickness is 70 μm to 130 μm. In this embodiment, the inner resin film 40 has a shape that covers the entire area of ​​the mirror-finished surface 11. In order to prevent the edge from contacting the bag body when the mirror-finished body 10 is housed in the bag body 21, it is formed to be larger than the diameter of the mirror-finished surface 11. When viewed from a direction perpendicular to the mirror-finished surface 11, the peripheral portion of the inner resin film 40 needs to be configured to protrude from the peripheral portion of the mirror-finished body 10. On the other hand, if the peripheral portion of the inner resin film 40 protrudes from the peripheral portion of the mirror-finished body 10 beyond what is necessary, wrinkles will form at the protruding portion near the edge of the mirror-finished body 10 when sealed under vacuum, and it may rub against the edge of the mirror-finished body 10 or the inner surface of the bag body 21. Therefore, the amount of protrusion of the inner resin film 40 relative to the periphery of the mirror-finished surface 11 is preferably less than the thickness of the mirror-finished body 10, for example, preferably less than half the thickness of the mirror-finished body 10.

[0032] The crystallinity of the inner resin film 40 is set to be 40% or more and 60% or less. Therefore, the generation of minute foreign matter originating from the resin film in contact with the mirror-finished surface 11 of the mirror-finished body 10 can be suppressed. Preferably, the crystallinity is 44% or more and 54% or less. Furthermore, it is more preferable that the crystallinity is 45% or more and 51% or less. If the crystallinity of the inner resin film 40 is less than 40%, the inner resin film 40 in contact with the mirror-finished surface 11 will be too soft, and the amorphous PE molecules adhering to the mirror-finished surface 11 may become tiny foreign objects. On the other hand, when the crystallinity of the inner resin film 40 exceeds 60%, the inner resin film 40 becomes hard and brittle, and a portion of the inner resin film 40 may peel off and become tiny foreign objects.

[0033] Furthermore, the first coefficient of friction between the surface of the inner resin film 40 on the bag body 21 side (the outer surface of the inner resin film 40) and the inner surface of the bag body 21 is less than the second coefficient of friction between the mirror-finished surface 11 and the surface of the inner resin film 40 that contacts the mirror-finished surface 11. The ratio of the second coefficient of friction to the first coefficient of friction (the value obtained by dividing the second coefficient of friction by the first coefficient of friction) is preferably 1.2 or higher. By making the second coefficient of friction greater than the first coefficient of friction, when the mirror-finished body 10, whose mirror-finished surface 11 is covered by the inner resin film 40, is housed inside the bag body 21, and when a vacuum is applied inside the bag body 21, relative movement between the mirror-finished surface 11 and the inner resin film 40 is suppressed, and relative movement occurs between the inner resin film 40 and the inner surface of the bag body 21. That is, mutual friction between the mirror-finished body 10 and the inner resin film 40 is prevented. In addition, the ratio of the second friction coefficient to the first friction coefficient is preferably 1.3 or higher, and even better, 1.5 or higher. Although there are no particular restrictions, the ratio of the second friction coefficient to the first friction coefficient can be below 10.0.

[0034] Packaging methods for mirror-finished products The packaging body 21 of the mirror-finished body 10 is placed inside the bag body 21 and sealed while the entire area of ​​the mirror-finished body 10 is covered by the inner resin film 40. The following is a detailed explanation. First, as shown in FIG. 5, the two inner resin films 40 are brought into contact with the mirror-finished surfaces 11 on the front and back sides of the mirror-finished body 10 to cover the entire area of ​​each mirror-finished surface 11 of the mirror-finished body 10. At this time, the configuration is such that when viewed from a direction perpendicular to the mirror-finished surface 11, the edge of the mirror-finished body 10 does not protrude beyond the outer side of the inner resin films 40, and when viewed from a direction perpendicular to the mirror-finished surface 11, the periphery of the inner resin films 40 protrudes from the periphery of the mirror-finished body 10. Then, as shown in FIG. 6, the mirror-finished body 10, with its entire area covered by the inner resin films 40, is placed inside the bag 21. Then, the air inside the bag 21 is evacuated, and the open end of the bag 21 is pressed onto a heated heating rod and welded to seal the bag 21 and put it in a sealed state. In this way, the mirror-finished body 10 is packaged in the bag 21, which becomes the packaging body 31 of the mirror-finished body 10.

[0035] As described above, in this embodiment, since the vacuum is drawn inside the bag body 21 while the mirror-finished surface 11, the inner resin film 40, and the bag body 21 are sequentially overlapped, if the first coefficient of friction between the inner surface of the inner resin film 40 on the bag body 21 side (the surface of the inner resin film 40 that faces the inner surface of the bag body 21) and the inner surface of the bag body 21 is greater than the second coefficient of friction between the mirror-finished surface 11 and the inner surface of the inner resin film 40 that contacts the mirror-finished surface 11, then during vacuuming, the inner resin film 40 and the inner surface of the bag body 21 become in close contact with each other, and displacement occurs between the mirror-finished body 10 and the inner resin film 40. Due to the friction between the mirror-finished surface 11 and the inner resin film 40, tiny foreign objects may be generated.

[0036] Therefore, in this embodiment, the first coefficient of friction between the surface of the inner resin film 40 on the bag body 21 side and the inner surface of the bag body 21 is set to be smaller than the second coefficient of friction between the mirror-finished surface 11 and the surface of the inner resin film 40 on one side that contacts the mirror-finished surface 11. Since the second coefficient of friction is set to be larger than the first coefficient of friction, when the mirror-finished body 10, whose mirror-finished surface 11 is covered by the inner resin film 40, is housed inside the bag body 21, and when a vacuum is applied to the bag body 21, no relative movement occurs between the mirror-finished surface 11 and the inner resin film 40; instead, relative movement occurs between the inner resin film 40 and the inner surface of the bag body 21. That is, since there is no friction between the mirror-finished body 10 and the inner resin film 40, the generation of minute foreign objects caused by friction between the mirror-finished body 10 and the inner resin film 40 can be suppressed. The ratio of the second coefficient of friction to the first coefficient of friction is preferably 1.2 or higher. In this case, since the inner resin film 40 slides more easily with the inner surface of the bag body 21 than with the inner resin film 40 with the mirror-finished surface 11, the generation of minute foreign objects caused by friction between the mirror-finished body 10 and the inner resin film 40 during storage or vacuuming can be reliably suppressed.

[0037] In this embodiment, when the mirror-finished body 10, with its mirror-finished surface 11 covered by the inner resin film 40, is housed within the bag body 21, the periphery of the inner resin film 40 protrudes from the periphery of the mirror-finished body 10. This prevents the edge of the mirror-finished body 10 from directly contacting the bag body 21 and generating minute foreign objects. Furthermore, since the inner resin film 40 is disposed between the mirror-finished body 10 and the bag body 21, the mirror-finished body 10 is protected by a two-layer structure of the bag body 21 and the inner resin film 40, thus providing more reliable protection for the mirror-finished body 10. Moreover, by setting the crystallinity of the inner resin film 40 within an appropriate range of 40% to 60%, the generation of minute foreign objects originating from the inner resin film 40 in contact with the mirror-finished surface 11 of the mirror-finished body 10 can be suppressed.

[0038] The present invention is not limited to the configuration of the above embodiments, and various changes can be made to the details without departing from the spirit of the present invention. For example, in the second embodiment, the inner resin film 40 is circular when viewed from above, but it is not limited to this; for example, it can also be rectangular.

[0039] In the second embodiment, the inner resin film 40 has a shape that covers the entire area of ​​the mirror-finished surface 11. However, the invention is not limited to this. For example, it may have a shape in which multiple holes are formed in the central portion of the inner resin film, without necessarily covering the entire area. Furthermore, the inner resin film 40 may have a shape that covers at least the periphery of the mirror-finished surface 11 (e.g., a shape that only covers the periphery of the mirror-finished surface). The inner resin film 40 can cover 3% to 100% of the total area of ​​the mirror-finished surface 11. When only the periphery of the mirror-finished surface 11 is covered, the inner resin film 40 can cover 1 to 15% of the total area of ​​the mirror-finished surface 11, or 2 to 10%, or 3 to 5%.

[0040] In the second embodiment, the bag body 21 can be formed of any material, but it is not limited to this; for example, it can be formed of the same material as the inner resin film 40. In this case, even if the inner resin film 40 is damaged and the resin film constituting the bag body comes into contact with the mirror-finished body, since the crystallinity of both the inner resin film 40 and the resin film constituting the bag body is within the aforementioned range, the generation of minute foreign objects can be suppressed even if the inner resin film 40 is damaged. Furthermore, since the same material is used, manufacturing costs can be reduced. [Example]

[0041] Silicon wafers (silicon plates) with a diameter of 380 mm and a thickness of 10 mm were prepared. A 700 mm × 800 mm polyethylene bag was used to contain the silicon plates. An inner resin film (samples A, B, and C) with a diameter of 390 mm and a thickness of 100 μm, made of polyethylene, was used to cover the entire mirror-finished surface of the silicon plates. The crystallinity of each sample A, B, and C was then measured, and the static and dynamic coefficients of friction between the inner resin film made from each sample A, B, and C and the inner surfaces of the silicon plates and the bag were also measured.

[0042] (Methods for determining crystallinity) The crystallinity of each sample A, B, and C was determined using XRD (X-ray diffraction). This determination was performed using an X-ray analysis apparatus (D8 Discover) manufactured by Bruker Co., Ltd., at any six points (n=6) spaced at least 1 cm apart on the resin film and the inner resin film (front and back sides). The crystalline and non-crystalline scattering intensities were calculated, and the crystallinity (average of the six points) was derived from these values. The results are shown in Table 1. In this embodiment, the crystallinity is calculated according to the following formula 1. Crystallinity Xc = Ic / (Ic + Ia) × 100 (Formula 1) Ic: Crystalline scattering intensity, Ia: Non-crystalline scattering intensity

[0043]

[0044] (Methods for determining static and kinetic friction coefficients) The static and dynamic friction coefficients were determined as follows. For the determination of the first coefficient of friction, a polyethylene bag, which will be the test object, is fixed to the testing equipment. With samples A, B, and C adhered to the pressure head, the pressure head with samples A, B, and C attached is positioned on the bag fixed to the testing equipment. Under a constant load, the pressure head moves a constant distance at a constant speed, thereby determining the static and dynamic coefficients of friction. For the determination of the second coefficient of friction, a silicon plate, which will be the test object, is fixed to the testing equipment. With samples A, B, and C adhered to the pressure head, the pressure head with samples A, B, and C attached is positioned on the silicon plate fixed to the testing equipment. The static and kinetic friction coefficients were determined by moving the indenter a constant distance at a constant speed under a constant load. Specifically, each sample was tested three times under the following conditions, and the average value and standard deviation were calculated. The test results for the static friction coefficient are shown in Table 2, and the test results for the kinetic friction coefficient are shown in Table 3. [Experimental Conditions] Equipment used: Tribogear TYPE 40 (manufactured by Shin-Dong Chemical) Speed: 1000mm / m Distance: 30mm Indenter used: φ12mm steel wool support Load: 200g

[0045]

[0046]

[0047] As shown in Table 2, in terms of static friction coefficients, the first friction coefficient of samples A, B, and C is less than the second friction coefficient, and the ratio of the second friction coefficient to the first friction coefficient is 1.4 or higher. Furthermore, as shown in Table 3, in terms of kinetic friction coefficients, the first friction coefficient of samples A, B, and C is less than the second friction coefficient, and the ratio of the second friction coefficient to the first friction coefficient is 1.7 or higher. As described above, regardless of whether it is static or kinetic friction coefficient, the first friction coefficient is less than the second friction coefficient in all samples. Therefore, it can be concluded that by using an inner resin film to cover the mirror-finished surface of the silicon board, when the silicon board is placed inside the bag and when a vacuum is applied inside the bag, no relative movement occurs between the mirror-finished surface and the inner resin film, but relative movement occurs between the inner resin film and the inner surface of the bag.

[0048] In addition, resin film 1 (e.g., sample A) was placed on the mirror-finished surface of a silicon board, and resin film 2 (sample A) was rubbed 5 times on the silicon board within a 3cm × 3cm area from resin film 1 (sample A), and resin film 2 (sample A) was rubbed 5 times directly on the mirror-finished surface within the above area without resin film 1 (sample A) being placed, and the generation state of tiny foreign matter was visually confirmed. The results are shown in Figures 7 and 8. Figure 7 is an image showing the friction range of the silicon plate when resin film 1 (sample A) is used, and Figure 8 is an image showing the above range of the silicon plate when resin film 2 is rubbed without using resin film 1 (sample A).

[0049] The experimental results of placing resin film 1 (sample A) on a silicon plate and rubbing it with resin film 2 over resin film 1 are shown in Figure 7, for example. No small foreign matter generated due to friction between resin film 1 and silicon plate was observed. On the other hand, when resin film 2 was rubbed directly against silicon plate without resin film 1 (sample A), as shown in Figure 8, small foreign matter was generated due to friction between silicon plate and resin film 2. Therefore, it can be seen that by simply placing an inner resin film, it is possible to suppress the small foreign matter generated by the friction of the resin film. Based on these findings, the experiment shown in the first embodiment was conducted below.

[0050] [First Embodiment] The aforementioned silicon slab and a bag with a planar dimension of 700mm × 800mm were fabricated. The bag material was made from resin films of samples A, B, and C, each with different crystallinity. Additionally, resin films of samples A, B, and C were prepared as inner resin films. Then, the silicon slabs, each covered with an inner resin film from sample A, B, and C, were placed in bags made from each of these samples A, B, and C and vacuum-sealed to create sample numbers 1 to 9. Next, each sample was unpacked, and the mirror-finished surfaces (both sides) of the silicon slabs were observed. The number of blemishes and particles, which are considered minute foreign objects, was measured and evaluated. Blemishes are defined as white, cloudy blemishes (approximately 1µm or larger) that can be visually observed in a dark room when illuminated from various angles at distances of 1cm, 3cm, and 5cm from an LED light with a brightness of 1000 lumens or higher. In addition, microparticles refer to point-like foreign objects (approximately 1 μm or larger) that can be visually observed when irradiated from various angles in a dark room at distances of 1 cm, 3 cm, and 5 cm from an LED light with a brightness of 300 lumens or more.

[0051] (Evaluation methods for the generation of minute foreign objects) Each sample, consisting of a silicon board covered with an inner resin film made from samples A, B, and C, was placed in a vacuum-sealed bag made from each of samples A, B, and C. The mirror-finished surfaces (both sides) of the silicon board were then observed, and the number of blemishes and particles (as tiny foreign objects) was measured. Blemishes were measured in a darkroom at distances of 1cm, 3cm, and 5cm from a 1000-lumen LED light. In Figure 9, angles α were measured in the ranges of 30°, 45°, and 80°, and angles β were measured in the ranges of 0°, 60°, 120°, 180°, 240°, and 320°. Furthermore, particle measurements were conducted in a dark room with distances to a 300-lumen LED light set to 1cm, 3cm, and 5cm. In Figure 9, angle α was measured within the ranges of 30°, 45°, and 80°, and angle β was measured within the ranges of 0°, 60°, 120°, 180°, 240°, and 320°. That is, due to the presence of 3 LED distances, 3 angles α, and 6 angles β, the number of stains and particles generated was measured under a total of 54 conditions (108 conditions combined for the front and back sides). The locations of stains or particles detected in the following evaluation are the sum of the locations of stains or particles detected in all 108 different ways of changing the aforementioned distances, angles α, and β. The evaluation criteria were applied to each stain or particle. If none were found, it was judged as "none"; if found at 1 to 3 locations, it was judged as "very few"; if found at 4 to 9 locations, it was judged as "few"; and if found at 10 or more locations, it was judged as "many". Furthermore, if there were no stains or particles, or if one was very few and the other was absent, it was judged as acceptable; otherwise, it was judged as unacceptable. The results are shown in Table 4. The crystallinity and friction coefficient ratio (second friction coefficient / first friction coefficient) of the inner resin film were detected using the above method.

[0052]

[0053] As shown in Table 4, when the bag body is manufactured by samples A, B, and C, and the inner resin film is manufactured by any one of samples A, B, and C, the generation of stains and particles can be largely eliminated. Furthermore, in the case of sample number 7, the value of the second friction coefficient / first friction coefficient (friction coefficient ratio) is the smallest, at 1.2, therefore it is considered that a very small number of stains were generated.

[0054] [Second Embodiment] A silicon plate and a bag with a planar dimension of 700 mm × 800 mm, as shown in the first embodiment, were fabricated. The bag material was made of resin films of samples A, B, C, D, E, and F, each with different crystallinity, and the bags were manufactured using these samples. Then, the silicon plate was placed in a bag made from each of these samples A, B, C, D, E, and F and vacuum-sealed to create each sample numbered 10 to 15. Next, these samples were unpacked separately, and the mirror-finished surfaces (both sides) of the silicon plate were observed. The number of stains and particles generated as micro-foreign matter was measured and evaluated. The method for detecting and evaluating stains and particles was the same as that shown in the first embodiment above. In addition, the following samples were prepared: samples A, B, and C were made of the same material as samples A, B, and C in the first embodiment above; sample D had a high crystallinity of 63%; and sample E had a low crystallinity of 35%. In addition, sample F containing additives was used. The crystallinity of each sample was detected and measured using the above method.

[0055]

[0056] As shown in Table 5, in sample number 15, the resin film of sample F contained additives and had extremely low crystallinity, resulting in a large number of stains and particles. Since crystallinity was not measured, it was judged as unqualified. Furthermore, in sample number 10, the resin film of sample D had a crystallinity as high as 63%, resulting in a small number of particles, and was judged as unqualified. Additionally, in sample number 14, the resin film of sample E had a crystallinity as low as 35%, resulting in a small number of stains, and was judged as unqualified. As mentioned above, a crystallinity of 43% to 58% for the resin film is considered acceptable. Summarizing the results of these samples, to suppress the generation of minute foreign matter caused by the resin film, it is considered appropriate to use a resin film constituting the bag body that has a crystallinity of 40% or more and 60% or less and does not contain additives. Specifically, in sample number 12, since no stains or particles were generated, a crystallinity of 48% (σ=3), i.e., a crystallinity of 45% or more and 51% or less, was found to be even better. [Industry availability]

[0057] A simple method can be used to suppress the formation of tiny foreign objects on the mirror-finished surface of a mirror-finished object.

[0058] 10: Mirror-finished body 11: Mirror-finished surface 20,21: Pocket 30, 31: Packaging of mirror-finished bodies 40: Inner resin film

Claims

1. A packaging body for a mirror-finished object, wherein the mirror-finished object having a mirror-finished surface is sealed in a bag made of a resin film under vacuum, characterized in that: the resin film constituting the bag is in contact with the mirror-finished surface, and the crystallinity of the resin film is 40% or more and 60% or less.

2. The packaging body of the mirror-finished body as requested in item 1, wherein, The crystallinity of the aforementioned resin film is above 44% and below 54%.

3. A packaging body for a mirror-finished object, wherein the mirror-finished object having a mirror-finished surface is sealed in a bag under vacuum, characterized in that: an inner resin film covering the mirror-finished surface is provided between the aforementioned mirror-finished surface and the inner surface of the aforementioned bag, and the periphery of the aforementioned inner resin film is arranged in such a way that it protrudes from the periphery of the aforementioned mirror-finished object.

4. The packaging body of the mirror-finished body as described in claim 3, wherein, The first coefficient of friction between the surface of the aforementioned inner resin film on one side of the bag and the inner surface of the aforementioned bag is less than the second coefficient of friction between the aforementioned mirror-finished surface and the surface of the aforementioned inner resin film that contacts the aforementioned mirror-finished surface.

5. The packaging body of the mirror-finished body as described in claim 4, wherein, The ratio of the aforementioned first friction coefficient to the aforementioned second friction coefficient is 1.2 or higher.

6. The packaging body of the mirror-finished body as claimed in any of claims 3 to 5, wherein the crystallinity of the aforementioned inner resin film is 40% or more and 60% or less.

7. A packaging method for a mirror-finished body, characterized in that: the mirror-finished body having a mirror-finished surface is placed in a bag made of a resin film with a crystallinity of 40% or more and 60% or less, and a vacuum is drawn and the bag is sealed while the resin film constituting the bag is in contact with the mirror-finished surface.

8. A packaging method for a mirror-finished body, characterized in that: the mirror-finished surface of the mirror-finished body is covered by an inner resin film with a crystallinity of 40% or more and 60% or less, and then vacuum-sealed inside a bag.

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