Packaging method for mirror-finished products

Abstract

To provide a mirror-finished body packing method and a mirror-finished body capable of suppressing adhesion of a minute foreign matter to a mirror-finished surface of the mirror-finished body.SOLUTION: The present invention provides a mirror-finished body packing method, including steps of: placing a mirror-finished body on a resin film; placing a part of the resin film or a resin film different from the resin film on the mirror-finished body; and sealing an entire circumference of an overlapped portion of the resin film positioned below and the resin film positioned above the mirror-finished body in a state in which internal air is removed.SELECTED DRAWING: Figure 5

Description

[[Technical Field]]

[0001] The present invention relates to a method for packaging a mirror-finished product, in which a mirror-finished product such as an electrode plate for plasma etchers requiring high cleanliness or a sputtering target for semiconductors In the law is packaged. [[Background Art]]

[0002] Conventionally, electrode plates for plasma etchers are known. When such an electrode plate is used in a state where foreign matter adheres to the mirror-finished surface (mirror surface) that has been subjected to mirror finishing, problems occur, so the mirror-finished surface is cleaned in advance to remove foreign matter before use. In order to suppress such adhesion of foreign matter, for example, a mirror-finished product is sealed in a bag under vacuum and transported. However, even when the mirror-finished product is transported in a vacuum-sealed state, the generation of foreign matter cannot still be suppressed, so further solutions are being sought.

[0003] For example, although the technical field is different, the methods described in Patent Document 1 and Patent Document 2 are known as packaging methods for glass substrates for magnetic disks having a mirror-finished surface. In the method for manufacturing a glass substrate for a magnetic disk of Patent Document 1, one or more glass substrates for a magnetic disk are housed in a case, the case is housed in a packaging bag, degassing is performed by depressurizing the inside of the packaging bag at a pressure reduction rate of 0.1 MPa / sec or less, and the opening of the packaging bag is sealed and hermetically closed in a state where the packaging bag is degassed. Further, the packaged body of a glass substrate for a magnetic disk of Patent Document 2 includes: a case that houses one or more glass substrates for a magnetic disk; a first light-shielding packaging bag made of a metal laminate film that seals the case in a degassed state; and a second packaging bag made of a plastic film that further seals the first packaging bag from the outside in a degassed state. That is, in the configurations of Patent Documents 1 and 2, a glass substrate for a magnetic disk is placed in a packaging bag and sealed in a degassed state to form a packaged body of the glass substrate for a magnetic disk. [[Prior Art Documents]] [Patent Documents]

[0004] [Patent Document 1] Patent No. 5234741 [Patent Document 2] Patent No. 5377849 [Overview of the project] [Problems that the invention aims to solve]

[0005] The methods described in Patent Documents 1 and 2 mentioned above involve placing the mirror-finished product into a packaging bag and then sealing it. As a result, when inserting the product into the packaging bag, minute foreign matter generated from the edges of the bag may adhere to the mirror-finished surface, leaving visible linear marks on the mirror-finished surface. Therefore, there is a need for a packaging method for mirror-finished products that can suppress the adhesion of minute foreign matter to the mirror-finished surface of the product, even with a simple packaging method such as packaging in a packaging bag made of resin film or the like.

[0006] This invention has been made in view of the above circumstances, and provides a method for packaging a mirror-finished product that can suppress the adhesion of minute foreign matter to the mirror-finished surface of the mirror-finished product. Law The purpose is to provide. [Means for solving the problem]

[0007] The present invention provides a method for packaging a mirror-finished product, which involves placing the mirror-finished product on a resin film, placing a portion of the resin film or a different resin film on the mirror-finished product, and sealing the entire circumference of the overlapping portion between the resin film located below the mirror-finished product and the resin film located above it, while removing the air from inside.

[0008] In this invention, the mirror-finished body is placed on a resin film, and a portion of the folded resin film is positioned on top of the mirror-finished body. The entire circumference of the overlapping portion of the upper and lower resin films, excluding the folded portion, is then joined. Alternatively, a different resin film is placed on top of the mirror-finished body, and the entire circumference of the overlapping portion of the upper and lower resin films is joined. This allows the mirror-finished body to be housed within a bag-shaped resin film. As a result, since no minute foreign matter is generated when the mirror-finished body is housed within the bag-shaped resin film, the adhesion of minute foreign matter to the mirror-finished surface of the mirror-finished body can be suppressed.

[0009] A preferred embodiment of the packaging method for a mirror-finished product of the present invention is to place the packaging, which is sealed with the resin film, inside a bag, and then seal the bag after removing the air from inside. In the above embodiment, the mirror-finished product is protected by a two-layer structure consisting of a bag and a resin film, thus providing more reliable protection for the mirror-finished product.

[0010] The mirror-finished body of the present invention has at least one surface that is a mirror-finished surface with an arithmetic mean roughness Ra of 0.2 μm or less, and when a light source is set up in a dark room so that the illuminance of the mirror-finished surface is 30,000 lux or more and 60,000 lux or less, and the surface of the mirror-finished surface is observed using the light source, there are 5 or fewer minute foreign objects with a circumscribed circle diameter of 1 μm or more on the entire surface of one of the mirror-finished surfaces.

[0011] In this invention, the number of minute foreign matter particles with a circumscribed diameter of 1 μm or more on the surface of a mirror-finished surface is small, at 5 or less per mirror-finished surface, making it easy to clean the mirror-finished surface. Needless to say, it is preferable that there be 0 of these minute foreign matter particles with a circumscribed diameter of 1 μm or more per mirror-finished surface, and if both sides of the mirror-finished body are mirror-finished surfaces, the number of minute foreign matter particles adhering to each side will be 5 or less. Furthermore, the darkroom mentioned above refers to a room in which light can be completely blocked, and the illuminance inside the room is set to 1 lux or less, more preferably 0 lux. [Effects of the Invention]

[0012] According to the present invention, adhesion of minute foreign matter to the mirror-finished surface of a mirror-finished body can be suppressed by a simple method. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] [Figure 1] FIG. 1 is a plan view showing a package of a mirror-finished body according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the mirror-finished body of the first embodiment. [Figure 3] FIG. 3 is a schematic view showing a state where the mirror-finished body is placed on a resin sheet in the method for packaging the mirror-finished body according to the first embodiment. [Figure 4] FIG. 4 is a schematic view showing a state where another resin sheet is placed on the mirror-finished body placed on the resin sheet in the method for packaging the mirror-finished body according to the first embodiment. [Figure 5] FIG. 5 is a schematic view showing a state where three sides of two resin sheets sandwiching the mirror-finished body are joined and internal air is degassed in the method for packaging the mirror-finished body according to the first embodiment. [Figure 6] FIG. 6 is a plan view showing a package of a mirror-finished body according to a second embodiment of the present invention. [Figure 7] FIG. 7 is a plan view showing a state where the mirror-finished body is placed on the right half of a resin sheet in the method for packaging the mirror-finished body according to the second embodiment. [Figure 8] FIG. 8 is a schematic view showing a state where the resin sheet is folded back, two sides are joined, and internal air is degassed in the method for packaging the mirror-finished body according to the second embodiment. [Figure 9] FIG. 9 is a schematic view showing a method for packaging a mirror-finished body according to a modified example of each of the above embodiments. [Figure 10] FIG. 10 is a view for showing detection conditions for minute foreign matter. MODE FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, embodiments of the method for packaging a mirror-finished body and the mirror-finished body of the present invention will be described with reference to the drawings.

[0015] [First Embodiment] The packaging 30 (hereinafter referred to as "packaging 30") of the mirror-finished body 10 in this embodiment is a packaging in which the mirror-finished body 10 having a mirror-finished surface 11 is sealed in a resin film bag 20 under vacuum, as shown in Figure 1. This mirror-finished body 10 is an electrode plate for a plasma etcher formed from, for example, Si (silicon), an intermetallic compound, or ceramics, and is formed in a disc shape as shown in Figure 2. The mirror-finished surface 11 is formed on both the front and back sides of the mirror-finished body 10.

[0016] For example, the mirror-finished body 10 has a diameter of 203 mm to 530 mm and a thickness of 3 mm to 19 mm, and the arithmetic mean roughness Ra of the mirror-finished surface 11 is 0.01 to 0.2 μm. This mirror-finished surface 11 is formed by polishing using a polishing machine.

[0017] The bag 20 is formed by overlapping two resin films 21 and 22, which have a larger surface area than the mirror-finished surface 11 of the mirror-finished body 10 in a plan view (see Figure 4), with its outer edge sealed by a sealing portion 29. As shown in Figure 1, the bag 20 is formed to be larger than the mirror-finished surface 11 of the mirror-finished body 10 in a plan view, and is sealed with the mirror-finished body 10 contained inside. The resin films 21 and 22 constituting such a bag 20 are made of, for example, polyethylene. In this case, it is preferable to use an additive-free type of resin that does not contain additives such as antioxidants or lubricants. The resin films 21 and 22 constituting the bag 20 are formed into a film shape by inflation molding or the like.

[0018] For example, the bag body 20 has a planar size of 100mm to 700mm x 150mm to 800mm and a thickness of 70μm to 130μm. The seal portion 29, which surrounds the entire circumference, is formed at a position of 70mm to 90mm from the edge of each side, and its width is 10mm to 15mm.

[0019] [Packaging method for mirror-finished products] In the conventional method of packaging mirror-finished products, a bag is typically constructed by sealing the outer edges of three sides of two overlapping resin films. The mirror-finished products are then placed inside the bag through the opening, and the air inside the bag is removed using a vacuum packaging device to seal the bag. In this case, if the edges of the mirror-finished products come into contact with the inner surface of the bag, there is a possibility that minute foreign matter originating from the bag may adhere to them. Therefore, it is necessary to store the products inside the bag in a way that minimizes contact with the inner surface of the bag, which is cumbersome. Furthermore, when storing a large number of mirror-finished products in a bag, it is impossible to prevent all the edges of the mirror-finished products from coming into contact with the bag, inevitably resulting in minute foreign matter adhering to the mirror-finished products. For this reason, in this embodiment, the packaging for mirror-finished products is formed in a way that eliminates the step of storing the mirror-finished products in a bag.

[0020] In this embodiment, the packaging 30 for the mirror-finished product 10 is constructed by placing the mirror-finished product 10 on a resin film 21, placing a different resin film 22 on top of the mirror-finished product 10, and sealing the entire circumference of the overlapping portion between the resin film 21 located below the mirror-finished product 10 and the resin film 22 located above it, while removing the air from inside. A detailed explanation follows below.

[0021] First, as shown in Figure 3, a mirror-finished body 10 is placed in the center of the resin film 21. Next, as shown in Figure 4, a resin film 22 is placed on top of the mirror-finished body 10. Both of these resin films 21 and 22 are rectangular in shape in plan view and are the same size. Then, as shown in Figure 5, a portion of the entire circumference of the overlapping resin films 21 and 22 (in this case, the outer edges of three sides) is sealed by pressing a heated heater rod against it and welding it. This sealing creates a U-shaped (approximately U-shaped) sealing portion 29 on the resin film 21, and the two resin films 21 and 22 are configured to form a bag (bag body 20). Then, a pipe of a vacuum device 40 is inserted into the opening on one side of the two bag-shaped resin films 21 and 22 that is not sealed, and the air inside the bag body 20 is vacuumed to seal and seal the portion of the bag body 20 on that side. As a result, the mirror-finished product 10 is packaged in the bag 20, becoming the packaged product 30 of the mirror-finished product 10 shown in Figure 1.

[0022] Then, when opening the packaging 30, the three sides of the bag 20 of the packaging 30 containing the mirror-finished product 10 are cut off one side at a time, along with the seal portion 29, and the resin film 22 located on the upper side of the mirror-finished product 10 is removed (peeled off) so that it does not come into contact with the edge of the mirror-finished product 10, and the mirror-finished product 10 is taken out of the bag 20. The mirror-finished product 10 taken out of the bag 20 will have fewer minute foreign matter attached to it.

[0023] Specifically, when the mirror-finished body 10, which has been packaged and removed using the method described above, is observed in a darkroom with a light source set so that the mirror-finished surface 11 is illuminated at 30,000 lux or more and 60,000 lux or less, there should be no more than 5 minute foreign particles with a circumscribed circle diameter of 1 μm or more per surface of one mirror-finished body. Preferably, there should be 0 minute foreign particles with a circumscribed circle diameter of 1 μm or more per surface of one mirror-finished body. Furthermore, in this embodiment, since both sides of the mirror-finished body 10 are mirror-finished surfaces 11, there should be no more than 5 minute foreign particles of the above size attached to each of the two mirror-finished surfaces 11 of the mirror-finished body 10. The darkroom refers to a room in which light can be completely blocked, and the illuminance inside the room is set to 1 lux or less, more preferably 0 lux. One mirror-finished surface 11 includes a processed surface formed on the front side of the mirror-finished body 10, or a processed surface formed on the back side of the mirror-finished body 10.

[0024] Thus, in this embodiment, when the surface of the mirror-finished body 10 is visually observed under an illuminance of 30,000 lux to 60,000 lux, there are no more than 5 minute foreign objects with a circumscribed circle diameter of 1 μm or more per surface of the mirror-finished body 10. For example, if the diameter of the mirror-finished body 11 is 200 mm, the number of these minute foreign objects will be 31,400 mm². 2 If there are 5 or fewer particles per unit area, and the diameter of the mirror-finished surface 11 is 320 mm, then the above minute foreign matter amounts to 80384 mm². 2 If there are 5 or fewer particles per unit area, and the diameter of the mirror-finished surface 11 is 380 mm, then the number of minute foreign particles is 113354 mm. 2 The number will be 5 or less per unit. From these results, the area of ​​one mirror-finished surface 11 is 31400 mm². 2 If the above conditions are met, the number of minute foreign objects with a circumscribed circle diameter of 1 μm or more is 31,400 mm. 2 The number will be 5 or less.

[0025] The measurement of minute foreign matter on the mirror-finished surface 11 described above is performed for multiple observation ranges set by changing at least the values ​​of α, β, and γ, as shown in Figure 10, where α is the irradiation angle of the angle light source with respect to a perpendicular line passing through the center of the mirror-finished surface 11, β is the angle around the center on the surface of the mirror-finished surface 11, and γ is the distance between the mirror-finished surface 11 and the light source. Specifically, the light source is positioned so that the illuminance on the mirror-finished surface 11 is between 30,000 lux and 60,000 lux, and in a darkroom, the distance γ from a 300-lumen LED light (light source) to the mirror-finished surface is set to 1, 3, and 5 cm, and the angles α in Figure 10 are measured in the ranges of 30°, 45°, and 80°, and the angles β in the ranges of 0°, 60°, 120°, 180°, 240°, and 320°. In other words, since there are 3 possible angles α, 6 possible angles β, and 3 possible distances γ for the LED light, we can measure minute foreign objects under a total of 54 conditions (108 conditions if we include both sides).

[0026] In the packaging method for the mirror-finished body 10 of this embodiment, a resin film 22 different from the resin film 21 is placed on top of the mirror-finished body 10 which is located on the resin film 21, and the entire circumference of the overlapping portion of the upper resin film 22 and the lower resin film 21 is joined to form a seal portion 29, thereby allowing the mirror-finished body 10 to be housed inside a bag-shaped resin film 21,22 (bag body 20). As a result, since minute foreign matter does not occur when the mirror-finished body 10 is housed inside the bag-shaped resin film, it is possible to suppress the adhesion of minute foreign matter to the mirror-finished surface 11 of the mirror-finished body 10.

[0027] For example, when the mirror-finished body 10 is an electrode plate or sputtering target for a plasma etcher, it is common practice to remove them from the bag, place them in a vacuum chamber, evacuate the vacuum, and then apply a voltage to the mirror-finished body 10 to generate plasma. In this case, if minute foreign matter adheres to the mirror-finished surface 11, abnormal discharge occurs starting from this minute foreign matter, causing the foreign matter to scatter onto the processing substrate in the case of a plasma etcher, or onto the film-forming substrate in the case of a sputtering target. In contrast, in this embodiment, the adhesion of minute foreign matter to the mirror-finished surface 11 of the mirror-finished body 10 can be suppressed, thereby suppressing abnormal discharge starting from minute foreign matter in subsequent processes and preventing the scattering of foreign matter onto the processing substrate or film-forming substrate.

[0028] Furthermore, since the number of minute foreign matter particles with a circumscribed circle diameter of 1 μm or more on the surface of the mirror-finished surface 11 is small (5 or less per mirror-finished surface), the mirror-finished surface 11 can be easily cleaned. In particular, if no minute foreign matter particles are attached to either mirror-finished surface 11 (i.e., the number of minute foreign matter particles attached to either mirror-finished surface 11 is 0), there is no need to clean the mirror-finished body, which further simplifies subsequent processes.

[0029] [Second Embodiment] Next, the packaging method for mirror-finished products according to the second embodiment will be described with reference to the drawings. In the following description, components that are the same as or substantially the same as those in the first embodiment will be given the same numbers, and their descriptions will be omitted or simplified. The packaging 30A (hereinafter referred to as "packaging 30A") for the mirror-finished body 10 in this embodiment is a packaging in which the mirror-finished body 10 having a mirror-finished surface 11 is sealed in a bag 20A under vacuum conditions, as shown in Figure 6. The differences from the first embodiment are that the bag 20A is made of a single resin film and the packaging method for the mirror-finished body 10 is different.

[0030] As shown in Figure 6, the bag 20A is formed to be larger than the mirror-finished body 10 in plan view, and has a shape in which a single resin film 23 is folded once and three sides are sealed by the seal portion 29A. The resin film 23 constituting this bag 20A is made of polyethylene or the like, as in the first embodiment. For example, the planar size of this bag 20A is 100 mm to 700 mm × 150 mm to 800 mm, and the thickness is 70 μm to 130 μm. In other words, the planar size of the resin film 23 constituting the bag 20A is set so that the length in the lateral direction is twice the length in the lateral direction of the bag 20A.

[0031] [Packaging method for mirror-finished products] The packaging 30A for the mirror-finished product 10 is constructed by placing the mirror-finished product 10 on a resin film 23, placing a portion of the resin film 23 on the mirror-finished product 10, and sealing the entire circumference of the overlapping portion between the resin film 23 located below the mirror-finished product 10 and the resin film 23 located above the mirror-finished product 10 while removing the air from inside. A detailed explanation follows below.

[0032] First, as shown in Figure 7, the mirror-finished body 10 is placed on the right-hand region of the resin film 21 (the region to the right of the center line L1). Next, as shown in Figure 8, the resin film 21 is folded back along the center line L1 and a portion of the resin film 23 is placed on the mirror-finished body 10. Then, as shown in Figure 8, the outer edges of a portion of the entire circumference of the overlapping resin film 23 (in this case, two sides (upper and lower sides in Figure 8)) are sealed by pressing a heated heater rod against them and welding them together. This sealing creates a sealed portion 29A on the resin film 23, and the resin film 23 is configured into a bag shape (bag body 20A). Then, the pipe of the vacuum device 40 is inserted into the opening on the unsealed side of the bag-shaped resin film 23, and the air inside the bag body 20A is vacuumed to seal and seal the portion of the bag body 20A on that side. As a result, the mirror-finished product 10 is packaged in the bag 20A, becoming the packaged product 30A of the mirror-finished product 10 shown in Figure 6.

[0033] When opening the packaging 30A, the three sides of the bag 20A of the packaging 30A containing the mirror-finished product 10, along with the seal portion 29A, are cut off, and a portion of the resin film 23 located above the mirror-finished product 10 is peeled back to remove the mirror-finished product 10 from the bag 20A. The removed mirror-finished product 10 will have minimal adhesion of minute foreign matter, similar to the first embodiment described above.

[0034] In this embodiment, the resin film 23 is folded over and a portion of it is placed on the mirror-finished body 10 located on the resin film 23. By joining the entire circumference of the overlapping portion between the upper resin film 23 (excluding the folded portion) and the lower resin film 23, the mirror-finished body 10 can be housed within the bag-shaped resin film 23. As a result, since minute foreign matter does not occur when the mirror-finished body is housed within the bag-shaped resin film, the adhesion of minute foreign matter to the mirror-finished surface of the mirror-finished body can be suppressed.

[0035] It should be noted that the present invention is not limited to the configurations of the embodiments described above, and various modifications can be made to the detailed configuration without departing from the spirit of the present invention. For example, in each of the embodiments described above, an example was shown in which the mirror-finished product 10 is packaged with a resin film. However, the invention is not limited to this, and as shown in Figure 9, the package 30 of the mirror-finished product 10 may be further housed in a bag 50 and sealed. In this case, since the mirror-finished product 10 is sealed with a resin film, the bag 50 may be a bag with three sides already closed. When the package 30 of the mirror-finished product 10 is further housed in a bag 50 and the bag 50 is sealed with the air inside removed, the mirror-finished product 10 is protected by a two-layer structure of the bag 50 and the resin film, thus providing more reliable protection for the mirror-finished product 10.

[0036] In the embodiments described above, the bags 20, 20A and the resin films constituting them are rectangular in plan view, but the invention is not limited to this, and for example, they may be circular in plan view.

[0037] In the second embodiment described above, a single resin film 23 is folded back. However, the invention is not limited to this configuration. Alternatively, the resin films 21 and 22 of the first embodiment may be overlapped, with only one side sealed, and the mirror-finished body 20 placed on the resin film 21 with the upper resin film 22 rolled up. In this case as well, the same effects as in the first and second embodiments can be achieved.

[0038] In the above embodiment, the entire upper and lower surfaces of the mirror-finished body 10 are assumed to be the mirror-finished surfaces 11. However, this is not limited to this, and for example, only one of the upper or lower surfaces of the mirror-finished body may be the mirror-finished surface. Furthermore, if a step is formed on one surface of the mirror-finished body to reduce the thickness of its outer edge, the mirror-finished surface will be formed only in the area inside that step. In other words, the area of ​​one surface of the mirror-finished body and the area of ​​the mirror-finished surface do not necessarily coincide. [Examples]

[0039] For Examples 1-3 and the Comparative Example, a silicon disc (Si electrode plate) with a diameter of 380 mm and a thickness of 10 mm was prepared as the sample (mirror-finished body). For Example 4, a silicon ring (Si ring) with a diameter of 380 mm, a thickness of 10 mm, and a hole diameter of 0.5 mm was prepared as the sample (mirror-finished body). For Example 5, a silicon target (Si target) with a diameter of 200 mm and a thickness of 6 mm was prepared as the sample (mirror-finished body). For Examples 1, 2, 4, and 5, the silicon plate, silicon ring, and silicon target were sealed using the method of Pattern 1. For Example 3, they were sealed using the method of Pattern 2, and for the Comparative Example, they were sealed using the conventional method.

[0040] (Method for sealing mirror-finished bodies) The sealing method for Pattern 1 involves preparing a 450mm x 400mm laminate film (manufactured by Sumika Sekisui Film Co., Ltd.: Thermoclean) with one side already sealed when opened. The sample (mirror-finished product) is placed on the open laminate film, and the open laminate film is placed over the product and closed. Then, the two unsealed sides are sealed, and the last side is sealed while degassing at 1000 Pa. In other words, the method for Pattern 1 is the same as the method for the second embodiment described above. Finally, the product is placed in a laminate bag that is sealed on three sides, and the last side is sealed while degassing at 1000 Pa. The sealing method for Pattern 2 involves preparing two 450mm x 400m sheets of laminate film (manufactured by Sumika Sekisui Film Co., Ltd.: Thermoclean) that are not sealed on any side. The sample is placed on one of the laminate films, and the other laminate film is placed over the sample. The three unsealed sides are then sealed, and the last side is sealed while degassing at 1000 Pa. In other words, the method for Pattern 2 is the same as the method for the first embodiment described above. Finally, the sample is placed in a laminate bag that is sealed on three sides, and the last side is sealed while degassing at 1000 Pa. Conventional sealing methods involve preparing a 450mm x 400mm laminate film (manufactured by Sumika Sekisui Film Co., Ltd.: Thermoclean) with three sides sealed, and placing the sample (mirror-finished object) inside the bag. Then, the last side (opening of the bag) is sealed while degassing at 1000 Pa. Finally, the sample is placed in a three-sided sealed laminate bag, and the last side is sealed while degassing at 1000 Pa.

[0041] The timing for checking for minute foreign matter was two: before sealing the sample and after sealing (after cutting the three sides along the seal portion and opening the package so that the edges of the laminate film do not touch the sample). To check for minute foreign matter, first, the sample (mirror-finished body) was placed on an observation stand, and the light source was positioned 10 mm above the foreign matter observation area on the sample so that the illuminance on the sample surface (mirror-finished surface) was between 30,000 lux and 60,000 lux, and the sample was observed visually from a 45° incline. A 300-lumen LED lamp was used as the light source. In addition to this visual observation, the mirror-finished surface of the sample (both sides or one side) was observed using the following method, and the number of minute foreign matter found was measured and evaluated.

[0042] (Method for evaluating the occurrence of minute foreign matter) To measure minute foreign matter with a circumscribed diameter of 1 μm or more, LED lights were positioned so that the illuminance on the mirror-finished surface 11 was between 30,000 lux and 60,000 lux. In a darkroom with an illuminance of 1 lux, the distance γ from the 300-lumen LED light to the mirror-finished surface 11 was set to 1, 3, and 5 cm. The angles α in Figure 10 were measured at 30°, 45°, and 80°, and the angles β were measured at 0°, 60°, 120°, 180°, 240°, and 320°. In other words, there were 3 possible distances γ for the LED light, 3 possible angles α, and 6 possible angles β, resulting in a total of 54 possible conditions (108 if both sides are mirror-finished surfaces). The number of minute foreign matter occurrences was measured under these conditions. During the measurement, minute foreign matter with a circumscribed diameter of 1 μm or more was observed visually. Furthermore, the circumscribed diameter of the minute foreign object is determined by a pre-set scratch scale (minimum scratch area 0.03 mm). 2 The measurement was performed by comparing the scratch scale (converted to a scale of 0.001 mm) with this scratch scale. The locations where minute foreign matter was detected in the following evaluation represent the total number of locations where minute foreign matter was detected in all 54 variations (108 variations) by changing the distance γ and angles α and β. The evaluation criteria were as follows: "None" if no minute foreign matter was found, the number of foreign matter found was indicated if it was less than 100, and "Present, 100 or more" if it was 100 or more. The results are shown in Table 2.

[0043] [Table 1]

[0044] [Table 2]

[0045] As shown in Table 2, in Examples 1 and 3-5, no foreign matter larger than 1 μm was found on the mirror-finished surface. In Example 2, however, a very small number of minute foreign matter larger than 1 μm was found, 5 on the front surface and 4 on the back surface, both before and after sealing. This is thought to be because the ionizer used to remove static electricity could not completely remove the particles attracted by static electricity to the mirror-finished surface. In other words, in Examples 1-5, where the mirror-finished body is placed on a resin film, a part of the resin film or a different resin film is placed on the mirror-finished body, and the entire circumference of the overlapping portion between the resin film located below and the resin film located above the mirror-finished body is sealed while the internal air is removed, it was found that the number of minute foreign matter adhering to the mirror-finished surface can be extremely reduced. In Example 5, observation of the back surface was unnecessary because it is the surface that will be bonded to the backing plate. On the other hand, in the comparative example, the mirror-finished product (silicon plate) was packaged by being placed in a bag, and it was found that the edges of the silicon plate came into contact with the bag during packaging, resulting in a large number of minute foreign particles adhering to it. [Explanation of symbols]

[0046] 10 Mirror finished body 11 Mirror-finished surface 20,20A bag body 21, 22, 23 Resin film 29,29A Seal section 30,30A Packaging for mirror-finished products 40 Vacuum pump 50 bags

Claims

1. A method for packaging a mirror-finished body made of silicon having a mirror-finished surface on at least one of its surfaces, A method for packaging a mirror-finished product, characterized by placing the mirror-finished product on a resin film, folding a portion of the resin film over and placing it on the mirror-finished product, and sealing the three sides of the overlapping portion of the resin film between the portion located below the mirror-finished product and the portion located above the mirror-finished product while removing the air from inside.

2. The method for packaging a mirror-finished product according to claim 1, characterized in that the packaging body, which is sealed with the resin film, is placed inside a bag, and the bag is sealed after the air inside is removed.

3. A method for packaging a mirror-finished body made of silicon having a mirror-finished surface on at least one of its surfaces, A method for packaging a mirror-finished product, characterized by: placing the mirror-finished product on a first resin film; placing a second resin film different from the first resin film on the mirror-finished product; sealing the entire circumference of the overlapping portion between the first resin film located below the mirror-finished product and the second resin film located above the mirror-finished product while degassing the air inside; thereby creating a package in which the mirror-finished product is sealed with the first resin film and the second resin film; then placing the package inside a bag and sealing the bag while degassing the air inside.

4. The method for packaging a mirror-finished body according to any one of claims 1 to 3, characterized in that the mirror-finished body has a diameter of 203 mm to 530 mm and the arithmetic mean roughness Ra of the mirror-finished surface is 0.01 μm to 0.2 μm.

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