JP2012234100A - Storage method for synthetic quartz glass substrate for photomask or photomask blank, carrying method, and storage case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent adsorption of out gas components from a storage case to a synthetic quartz glass substrate for a photomask and a photomask blank and simultaneously suppress fixing of minute foreign matter to the surface of the substrate or the like.SOLUTION: The storage method for a synthetic quartz glass substrate for a photomask or a photomask blank includes: preparing a storage case; installing an adsorbent which is packed in a cellulose-based nonwoven fabric, in the interior of the storage case; and storing the synthetic quartz glass substrate for the photomask or the photomask blank in the storage case.

Description

  The present invention relates to a storage method, a transport method, and a storage case for a synthetic quartz glass substrate for photomask or a photomask blank.

  As semiconductor devices are highly integrated, there is an increasing demand for miniaturization in the photolithography process. A photomask used for photolithography is manufactured by forming a light-shielding thin film made of chromium or the like on a synthetic quartz glass substrate, further applying a resist, and then performing processes such as drawing, developing, and etching with an electron beam or the like. . A state in which a light shielding film is formed on a synthetic quartz glass substrate before drawing is called a photomask blank.

  With miniaturization of wiring patterns in semiconductor devices, there is a need for a technique that does not cause film formation unevenness or application unevenness in the formation of a light shielding film on a synthetic quartz glass substrate and the application of a resist on a photomask blank. From such a demand, a very high cleanliness is also required for a synthetic quartz glass substrate and a photomask blank (hereinafter referred to as “substrate etc.” if necessary). For this reason, the storage of the substrate or the like is required to suppress foreign matters and the like from adhering to the substrate and maintain the cleanliness as high as possible.

  By the way, a storage case for a substrate or the like is formed, for example, by melting and bonding a resin plate such as polyacrylonitrile with an organic solvent such as acetonitrile, that is, by welding. And it becomes a problem that the chemical component of the outgas derived from the resin material of the storage case is adsorbed on the surface of the substrate or the like stored therein. The amount of outgas from the bonded portion of the welded resin plate is particularly large.

  As proposals for preventing adsorption of chemical components to the substrate, Patent Documents 1 to 3 disclose a case equipped with a filter containing activated carbon and a filter mechanism thereof. According to these, by eliminating the pressure difference between the inside and outside of the case, it is possible to prevent contamination from the external environment due to the pressure difference generated during transportation. On the other hand, in patent document 4, activated carbon is arrange | positioned in the storage case in order to remove organic substance.

JP 2004-153221 A JP 2004-179449 A JP 2004-193272 A JP 2009-55005 A

  However, the techniques disclosed in Patent Documents 1 to 3 are insufficient as a countermeasure against outgas resulting from the material of the storage case. Moreover, in patent document 4, the synthetic resin type nonwoven fabric is used for the packaging material of activated carbon. Since the synthetic resin-based nonwoven fabric has a low gas permeability, the technology disclosed in Patent Document 4 cannot sufficiently adsorb chemical components. In addition, fine dust is generated from the synthetic resin nonwoven fabric which is a packaging material of activated carbon. If minute foreign matter adheres and adheres to the surface of a substrate or the like during storage, it cannot be removed by cleaning.

  Therefore, the present invention was made to solve the above problems, and in the method for storing a synthetic quartz glass substrate for photomask and a photomask blank, it prevents adsorption of outgas components from the storage case to the substrate, etc. An object is to suppress the adhesion of minute foreign substances to the surface of a substrate or the like.

  According to the first aspect of the present invention, there is provided a method for storing a synthetic quartz glass substrate for a photomask or a photomask blank, wherein a storage case is prepared, and an adsorbent packaged in a cellulosic nonwoven fabric is stored in the storage case. And a method for storing the synthetic quartz glass substrate for photomask or the photomask blank, including storing the synthetic quartz glass substrate for photomask or the photomask blank in the storage case.

  According to the second aspect of the present invention, the synthetic quartz glass substrate for photomask or the photomask blank is transported in a state where the synthetic quartz glass substrate for photomask or the photomask blank is stored by the method for storing the synthetic quartz glass substrate for photomask or the photomask blank of the first aspect. Provided is a method for transporting a synthetic quartz glass substrate or a photomask blank for a photomask.

  According to the 3rd aspect of this invention, it is a storage case of the synthetic quartz glass substrate for photomasks, or a photomask blank, Comprising: The adsorption agent packaged by the cellulose nonwoven fabric is installed in the inside of the said storage case A storage case for a synthetic quartz glass substrate for photomask or a photomask blank is provided.

  In the method for storing a synthetic quartz glass substrate for a photomask or a photomask blank according to an embodiment of the present invention, the absorbent is packaged with a cellulose-based nonwoven fabric having high air permeability, so that the gas absorbing ability of the absorbent can be sufficiently exhibited. Thereby, the outgas in a storage case is absorbed efficiently and adsorption | suction of the board | substrate etc. of an outgas component can be suppressed. As a result, it is possible to prevent film formation unevenness and photoresist application unevenness of the light-shielding film on the stored substrate or the like. In addition, the cellulose-based nonwoven fabric is less likely to have dust derived from it adhered to the surface of a substrate or the like, and can be easily removed by washing even if it adheres. Therefore, it is possible to suppress the adhesion of minute foreign matters to the surface of the substrate or the like.

It is a flowchart explaining the storage method of the synthetic quartz glass substrate for photomasks of 1st Embodiment. It is the schematic of the storage case of the synthetic quartz glass substrate for photomasks used in 1st Embodiment. (A) And (b) is sectional drawing of the storage case of the synthetic quartz glass substrate for photomasks used in 1st Embodiment. (C) is a top view of the case main body which comprises a storage case. It is a perspective view of the synthetic quartz glass substrate for photomasks and the storage case used in the first embodiment. It is the schematic of the package used in 1st Embodiment. It is the schematic of a mode that the packaging body used in 1st Embodiment is manufactured by pressing. It is a figure which shows the measurement position of the contact angle of the synthetic quartz glass substrate for photomasks used in Example 1.

[First Embodiment]
As a first embodiment of the present invention, a method for storing a synthetic quartz glass substrate for a photomask will be described with reference to FIG. The synthetic quartz glass substrate for a photomask is a substrate for forming a photomask serving as a master for photolithography. And what formed the light shielding film which consists of chromium etc. on the synthetic quartz glass substrate for photomasks is a photomask blank. In this embodiment, a method for storing a synthetic quartz glass substrate for a photomask will be described, but a photomask blank can also be stored by the same method. Further, a quartz glass substrate to which an additive such as titanium oxide is added can be used, but is not particularly limited.

  First, a storage case 1 for storing a synthetic quartz glass substrate 10 for photomask (hereinafter referred to as “substrate 10” as necessary) is prepared (step 1). As shown in FIGS. 2 to 4, the storage case 1 of the present embodiment has, for example, a rectangular parallelepiped box shape with an open top surface, and a box-shaped case body that accommodates a rectangular plate-like substrate 10 therein. 2 and a lid 3 that covers the opening of the case body 2 and is detachably attached to the case body 2. The case body 2 includes a rectangular bottom plate 21, a pair of first side walls 22 that are coupled to the long side of the bottom plate 21 and opposed to each other, and a pair of second side walls 23 that are coupled to the short side of the bottom plate 21 and opposed to each other. Become. The second side wall 23 connects a pair of first side walls 22 facing each other. The storage case 1 is a vertical storage case that stores the substrate 10 in a substantially vertical position. Regarding the bottom plate 21, the first side wall 22, and the second side wall 23, the surfaces that form the inside of the storage case 1 are referred to as “inner surfaces”, and the surfaces that form the outside of the storage case 1 are referred to as “outer surfaces”. When the substrate 10 is stored, the inner surface of the first side wall 22 faces the surface of the substrate 10. On the other hand, the inner surface of the second side wall 23 faces the end surface of the substrate 10 and holds the substrate 10 via a support member 27 described later.

  On the outer surfaces of the first and second side walls 22 and 23, a collar 24 is provided so as to protrude. The flange 24 is connected and provided so as to go around the outside of the case body 2 over the four outer surfaces of the first and second side walls 22 and 23. A portion of the case body 2 located on the upper surface side (opening side) from the flange 24 is referred to as a fitting portion 25.

  The lid 3 is a rectangular parallelepiped box having an open bottom surface, and includes an upper plate 31 and two pairs of lid side walls 32 and 33 that are connected to the upper plate 31 and face each other. Regarding the upper plate 31 and the lid side walls 32, 33, the surfaces forming the inner side of the storage case 1 are referred to as “inner surfaces”, and the surfaces forming the outer side of the storage case 1 are referred to as “outer surfaces”. Lower end portions (end portions on the opening side) of the outer surfaces of the lid side walls 32 and 33 protrude outward and form a flange 34. The flange 34 is provided so as to make a round around the outside of the lid 3 over the four outer surfaces of the lid side walls 32 and 33.

  As shown in FIG. 3, the lid 3 is attached to the case body 2 by fitting the fitting portion 25 of the case body 2 into the opening on the lower surface thereof. At this time, the reeds 24 and 34 of the case body 2 and the lid 3 are in contact with each other. In order to improve the hermeticity of the storage case 1, the case body 2 has an annular elastic member 26 along the inner edge of the flange 24.

  Furthermore, a support member 27 that supports the substrate 10 when the substrate 10 is stored is provided on the inner surfaces of the second side wall 23 and the bottom plate 21. The support member 27 is a rod-shaped member having a recess at the center, and the center recess extends along the longitudinal direction of the support member 27. That is, the cross section perpendicular to the longitudinal direction of the support member 27 is concave, and the substrate 10 is supported by sandwiching the end of the substrate 10 in the recess. A tube 37 is provided on the inner surface of the upper plate 31 of the lid 3. When the lid 3 is attached to the case body 2, the tube 37 contacts the upper end surface (end surface on the lid side) of the substrate 10. The substrate 10 is supported by a tube 37 on the lid side and a support member 27 on the case body side.

  Examples of the material constituting the case body 2, the lid 3, the support member 27, and the tube 37 include polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polyacrylonitrile (PAN), and polyether ether ketone (PEEK). , Polyurethane (PU), polystyrene (PS), polymethyl methacrylate (PMMA), polytetrafluoroethylene (PTFE), polymethacrylonitrile (PMAN), polymethyl acrylate (PMA), polyethyl methacrylate (PEMA), etc. Or a synthetic resin composed of these copolymers. Of these, polycarbonate (PC) or polyacrylonitrile (PAN) is preferable as the material of the case body 2 and the lid 3 because it is easy to process and the manufacturing cost is low, and the material of the support member 27 and the tube 37 is high density. Polyethylene (HDPE) or polytetrafluoroethylene (PTFE) is preferred because it emits less chemical component gases. As the elastic member 26, for example, a polyolefin elastomer or a polyester elastomer can be used.

  The storage case 1 can be formed by bonding a resin plate using a solvent, an adhesive, or the like. For example, a resin plate such as polyacrylonitrile is formed by welding with an organic solvent such as acetonitrile.

  Next, an adsorbent packaged in a cellulosic nonwoven fabric is placed inside the prepared storage case 1 (step 2). As shown in FIG. 5, in this embodiment, a package 4 in which an adsorbent 42 is packaged inside a cellulose-based nonwoven fabric 41 processed into a flat bag shape is produced, and as shown in FIGS. 2 and 3, Five package bodies 4 were bonded to the inner surface of the first side wall 22 using an adhesive.

Cellulose-based nonwoven fabric refers to a sheet-like material in which fibers derived from plant cellulose are intertwined without being woven. Plant cellulose-derived fibers are, for example, natural plant fibers such as cotton, hemp, jute and paper, and regenerated cellulose fibers such as rayon and cupra. In particular, regenerated cellulose having a fiber density of 0.002 to 0.004 g / cm ² is preferable in terms of adsorption capacity.

  Cellulose-based non-woven fabrics have higher air permeability than synthetic resins such as polyester that have been conventionally used as adsorbent packaging materials, and adsorbents packaged in cellulosic-based non-woven fabrics can sufficiently exhibit gas absorption capacity. . As described above, the storage case of the synthetic quartz glass substrate is formed of a synthetic resin, and the plasticizer, the solvent used for welding, or the adhesive component contained therein is generated in the storage case as an outgas component. If the surface of the synthetic quartz glass substrate is contaminated by adsorption of outgas components, a light shielding film cannot be uniformly formed on the surface. Similarly, when the surface of the photomask blank is contaminated with an outgas component, the resist film cannot be applied uniformly. Since an outgas component adsorbed on the surface of a synthetic quartz glass substrate or the like cannot be removed by cleaning, it is necessary to suppress adsorption to the surface. In this embodiment, since the outgas concentration in a storage case falls by installing the adsorption agent contained in the cellulose nonwoven fabric in a storage case, adsorption | suction to the board | substrate etc. of an outgas component can be suppressed. As a result, it is possible to prevent film formation unevenness and photoresist application unevenness of the light-shielding film on the stored substrate or the like.

  Furthermore, in the cellulose-based nonwoven fabric, dust derived therefrom is difficult to adhere to the substrate surface. The dust generated from the cellulosic nonwoven fabric is a cellulose fiber that forms the cellulosic nonwoven fabric, and the fiber length is longer than that of the synthetic resin nonwoven fabric. Therefore, the dust derived from the cellulosic nonwoven fabric is large and the surface area is small, so that the adsorptive power to the substrate is low. Furthermore, even if the dust derived from the cellulosic nonwoven fabric adheres to the substrate surface, the adsorbing power is weak, so it can be easily removed by washing and is difficult to adhere. Therefore, if the substrate or the like is stored using the adsorbent contained in the cellulose-based nonwoven fabric, the adhesion of minute foreign matters to the surface of the substrate or the like can be suppressed. Thus, the length of the fiber length of the cellulosic nonwoven fabric is preferably 500 μm to 5000 μm from the viewpoint of suppressing the adhesion of minute foreign matters to the surface of the substrate or the like.

  Although various forms can be used for the absorbent packaging with the cellulose-based nonwoven fabric, the cellulose-based nonwoven fabric may be processed into a bag shape, and the adsorbent may be held therein. From the viewpoint of processability, it is preferable to process the cellulosic nonwoven fabric into a flat bag shape. “Flat bag” means a bag having no wrinkles. In this embodiment, as shown in FIG.5 and FIG.6, the adsorbent 42 is pinched | interposed with the cellulosic nonwoven fabric 41, the circumference | surroundings of adsorbent are sealed by squeezing in barcode form, and the package 4 is produced. As a material of the pressing part 5 of a pressing machine, metal materials, such as stainless steel and cast iron, are preferable, for example, As a shape, it can be set as a mountain shape and uneven | corrugated shape. Cellulose-based nonwoven fabrics are resistant to heat, and cannot be processed into bags by heat welding like conventional synthetic resin-based nonwoven fabrics, but can be processed into flat bags by pressing.

  As the adsorbent 42, for example, various forms of activated carbon such as powdered activated carbon, granular activated carbon, spherical activated carbon, fibrous activated carbon, silica gel, calcium chloride, and zeolite can be used. Shaped activated carbon is preferred.

  The packaging body 4 is preferably 40 × 40 to 150 × 150 mm in size from the viewpoint of handleability, and preferably contains about 5 to 50 g of an absorbent. The amount of can be selected as appropriate.

  The package 4 is installed at a position where it does not contact the substrate 10 stored in the storage case 1. This is to prevent the substrate 10 from being contaminated by the package 4 coming into contact with the substrate 10. Further, the substrate 10 may be transported while being stored in the storage case 1. Therefore, it is preferable that the packaging body 4 is fixed inside the storage case 1 so that the installation position does not change even if vibration due to transportation is transmitted to the storage case 1. In this embodiment, as shown in FIG.2 and FIG.3, the package 4 is fixed to the inner surface of the 1st side wall 22 with an adhesive. When the substrate 10 is stored in the storage case 1, the package 4 is positioned opposite to the surface of the substrate 10 and does not come into contact therewith. Further, since it is fixed inside the storage case 1, it does not come into contact with the substrate 10 even if vibration is given to the storage case 1.

  In the present embodiment, five packaging bodies 4 are used, but the number of installations is appropriately selected depending on the relationship between the volume of the storage case 1 and the gas adsorption capacity of the absorbent 5. In this embodiment, the installation location is also set only on one of the pair of first side walls 22, but it may be set on the other opposing inner surface. Moreover, in the present Example, although the package 4 was fixed to the inner surface of the storage case 1 with the adhesive, the installation method to the storage case 1 of the package 4 is not limited to this. For example, a method of preparing an installation place where the packaging body 4 can be fixed in the storage case 1 in advance and fixing the packaging body to the installation place is conceivable.

  Next, the substrate 10 is stored in the storage case 1 (step 3). First, the substrate 10 is accommodated in the main body case 2 using a general jig. At this time, the support member 27 provided on the second side wall 23 of the case body 2 serves as a guide for guiding the substrate 10 to the back of the case body 2. From this viewpoint, it is preferable that the support member 27 is formed of PTFE so that the substrate 1 can easily slide on the support member 27. When the substrate 10 is stored in the main body case 2, the substrate 10 is prevented from coming into contact with the package 4 installed in the storage case 1 in order to prevent contamination of the surface of the substrate 10. Then, after the substrate 10 is stored in the main body case 2, the lid 3 is attached to the main body case 2. The tube 37 of the lid 3 is in contact with the upper end surface (end surface on the lid side) of the substrate 10, and the substrate 10 is supported by the tube 37 on the lid side and the support member 27 on the case body side. Further, an adhesive tape is wound around the contact portion (joint) of the main body case 2 and the lids 24 and 34 of the lid 3 over the circumference of the storage case 1. Thereby, the fitting of the main body case 2 and the lid 3 can be strengthened, and the hermeticity of the storage case 1 can be improved.

  As the substrate 10, a rectangular plate-shaped substrate having a short side of 300 mm or more and a long side of 400 mm or more can be used. For example, the substrate size is short side (mm) × long side (mm), 330 × 450, 370 × 450, 420 × 520, 420 × 530, 430 × 530, 440 × 520, 500 × 750, 520 × 610, 520 × 800, 620 × 720, 650 × 750, 650 × 800, 700 × 800, 800 × 920, 700 × 1,100, 800 × 960, 830 × 960, 850 × 1,000, 830 × 1,196, 850 These are synthetic quartz glass substrates for photomasks such as × 1,200, 830 × 1,396, 810 × 1,380, 850 × 1,400, 1,220 × 1,400, 1,620 × 1,780.

[Second Embodiment]
The second embodiment of the present invention is a method for transporting a synthetic quartz glass substrate for a photomask that transports the synthetic quartz glass substrate for a photomask stored by the storage method of the first embodiment. In this embodiment, the adsorption | suction to the board | substrate of the outgas component from a storage case is prevented, and a board | substrate can be conveyed in a clean state. As a result, film formation unevenness of the light shielding film on the transported substrate can be prevented.

  Moreover, since the vibration by conveyance is transmitted to a storage case at the time of conveyance, it is anticipated that the dust generated from a cellulose nonwoven fabric will increase compared with the case where it is left still. However, dust generated from the cellulosic nonwoven fabric is large in size, hardly adheres to the substrate, and can be easily removed by washing. Therefore, the transport method of this embodiment can also prevent the adhesion of minute foreign matters to the substrate surface.

[Third Embodiment]
As shown in FIGS. 2 and 3, the third embodiment of the present invention is a storage case of a synthetic quartz glass substrate for a photomask in which an adsorbent wrapped with a cellulose-based nonwoven fabric is installed inside the storage case. is there. The storage case of this embodiment is a storage case used for the storage method of the first embodiment. Since the adsorbent packaged with a highly breathable cellulose-based nonwoven fabric absorbs outgas efficiently, contamination of the substrate due to outgas component adsorption can be suppressed. Moreover, since the dust generated from the cellulosic nonwoven fabric is large, it hardly adheres to the substrate surface and can be easily removed by washing. Therefore, the storage case of the present embodiment also prevents sticking of minute foreign matters to the substrate surface stored therein.

  In the first to third embodiments, the storage method, the transport method, and the storage case of the synthetic quartz glass substrate have been described. The photomask blank can also be stored and transported in the same manner. There is an effect. Further, in the first to third embodiments, the vertical storage case that stores the substrate in a state of being substantially perpendicular to the ground has been described. It may be a horizontal storage case that is stored in a substantially horizontal state. Furthermore, in the first to third embodiments, the storage case for storing one substrate has been described, but the storage case may be a storage case for storing two or more substrates.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not restrict | limited to the following Example.
[Example 1]
The synthetic quartz glass substrate 10 was stored for a certain period in the storage case 1 shown in FIG. 2, and the contact angle of the surface of the substrate 10 before and after storage was measured.

  First, as the storage case 1, a vertical storage case was prepared in which a rectangular plate-shaped synthetic quartz glass substrate 10 of 850 mm × 1200 mm × 10 mm was stored in a state of being substantially perpendicular to the ground. The size of the internal space of the storage case 1 for storing the substrate 1 is about 850 mm × about 1200 mm × about 130 mm. The case body 2 and the lid 3 were made of polyacrylonitrile (PAN), the support member 27 and the tube 37 were made of polytetrafluoroethylene (PTFE), and the elastic member 26 was made of a polyolefin elastomer.

  Next, the package 4 in which the adsorbent was packaged with a cellulose-based nonwoven fabric was placed on the inner surface of the first side wall 22. There are two inner surfaces of the first side wall 22 facing each other. In the present embodiment, the packaging body 4 is installed only on one surface. As shown in FIG. 5, the package 4 was sealed by wrapping fibrous activated carbon (adsorbent) 42 with a cellulose-based non-woven fabric 41 and pressing the ends of the non-woven fabric 41 with barcode-type irregularities. Toyobo's K filter (activated carbon 7.5 g / piece) was used as the activated carbon 42, and Asahi Kasei Fibers Co., Ltd.'s Bencot M-3II was used as the nonwoven fabric 41. There are five installation positions of the package body 4, that is, a position that enters inside by 50 mm vertically and horizontally from four corners of the inner surface of the first side wall 22, and a substantially central position.

  A synthetic quartz glass substrate 10 stored in the storage case 1 was prepared, and after cleaning, the contact angle with pure water was measured using a contact angle measuring device. As shown in FIG. 7, the contact angle of 5 points of the position (measurement position 11-14) which entered inside 50 mm vertically and horizontally from the four corners of the surface of the synthetic quartz glass substrate and the substantially center position (measurement position 15) of the substrate surface. Was measured. The results are shown in Table 1.

  Next, the board | substrate 10 was accommodated in the storage case 1 in which the above-mentioned package 4 was installed. In the storage case 1, the end surface of the substrate 10 is supported by a support member 27 provided on the second side wall 23, and the measurement positions 11 to 15 on the surface of the substrate 10 are opposed to the package 4 provided on the first side wall 22. To do. The distance between the surface of the substrate 10 and the inner surface of the storage case 1 facing the inner surface (the inner surface of the first side wall 22) was 60 mm.

  After the substrate 10 is stored in the case body 2, the lid 3 is attached to the case body 2, and further, the tape is wrapped around the joint between the case body 2 and the lid 3, and the entire storage case 1 is packed in a packaging bag. The substrate 10 was stored for 22 days. These storage operations and storages were performed in a clean room cleaned with a ULPA filter.

  After storage for 22 days, the storage case 1 was opened in a clean room, and the substrate 10 was taken out of the storage case 1. The contact angles at the measurement positions 11 to 15 on the surface of the substrate 10 taken out were measured by the same method as described above. The results are shown in Table 1.

[Comparative Example 1]
The synthetic quartz glass substrate was stored for 22 days in the same manner as in Example 1 except that a storage case without the package 4 was used. Before and after storage, five contact angles at measurement positions 11 to 15 on the substrate surface were measured. The results are shown in Table 1.

[Comparative Example 2]
The synthetic quartz glass substrate was stored for 22 days in the same manner as in Example 1 except that a storage case in which a package in which activated carbon was wrapped with a polyester nonwoven fabric was used instead of the package 4. Before and after storage, five contact angles at measurement positions 11 to 15 on the substrate surface were measured. The results are shown in Table 1.

  As shown in Table 1, the contact angles of the substrate surfaces before storage in Example 1, Comparative Example 1 and Comparative Example 2 are 4.5 °, 4.2 ° and 4.3 °, respectively, which are substantially the same. there were. The contact angle after storage was 11.8 ° in Example 1, whereas it was greatly increased to 28.1 ° and 23.5 ° in Comparative Example 1 and Comparative Example 2, respectively. That is, compared with Example 1, in Comparative Example 1 and Comparative Example 2, the water repellency of the substrate surface was higher by storage than before storage.

  The improvement in water repellency of the substrate means that some chemical component or the like is adsorbed on the surface of the substrate, and it is assumed that the substrate surface is contaminated by the adsorption of outgas derived from the storage case. Since the contact angle of the substrate surface after storage in Example 1 is kept low compared to Comparative Example 1 using a storage case in which no adsorbent is arranged, the adsorption packaged in a cellulose-based nonwoven fabric It can be seen that the agent adsorbs and removes the outgas generated from the storage case and suppresses the contamination of the substrate.

  Moreover, even if compared with the comparative example 2 using the polyester-type nonwoven fabric as a packaging material of activated carbon, the contact angle of the example 1 after storage is suppressed low. From this, it can be seen that the cellulose-based nonwoven fabric is superior to the polyester-based nonwoven fabric as the packaging material for the activated carbon, and is effective in suppressing the contamination of the substrate.

[Example 2]
The synthetic quartz glass substrate is stored for 22 days in the same manner as in Example 1, and then the synthetic quartz glass substrate is stored for night transportation (running on a general road for 12 hours on a 4t truck) at an outdoor temperature of about 0 ° C. went. After transportation, the synthetic quartz glass substrate was taken out of the storage case, and the surface thereof was visually observed. As a result, several deposits could be confirmed on the substrate surface. Thereafter, it was found that when the substrate was cleaned, the deposits decreased or moved.

[Comparative Example 3]
The synthetic quartz glass substrate is stored for 22 days in the same manner as in Comparative Example 2, and then the synthetic quartz glass substrate is stored for night transportation (running on a general road for 12 hours on a 4t truck) at an outdoor temperature of about 0 ° C. went. After transportation, the synthetic quartz glass substrate was taken out of the storage case, and the surface thereof was visually observed. As a result, several hundred deposits were observed on the substrate surface. Thereafter, the substrate was cleaned, but the amount of deposits hardly decreased.

  In Example 2, it was found that the amount of deposits on the substrate was smaller than that of Comparative Example 3, and the deposits were easily removed by washing. The deposits on the substrate surface observed in Example 2 and Comparative Example 3 are presumed to be dust derived from a cellulose-based nonwoven fabric and dust derived from a polyester-based nonwoven fabric, respectively. Compared with the dust derived from a polyester nonwoven fabric, the dust derived from a cellulose nonwoven fabric is large in size, and is therefore difficult to adsorb to the substrate. For this reason, in Example 2, it is thought that there were few deposits on the substrate surface. Moreover, since the dust derived from the cellulose-based nonwoven fabric is difficult to adhere due to static electricity, there are few deposits on the substrate of Example 2, and it is considered that the deposits were easy to remove by washing.

[Reference example]
Cellulosic nonwoven fabric and synthetic resin nonwoven fabric were observed for dust generated from each. As a cellulose-based non-woven fabric, manufactured by Asahi Kasei Fibers Co., Ltd., Bencott M-3II (sample A), and as a synthetic resin-based non-woven fabric, polyethylene terephthalate (PET) (sample B) and polypropylene are used. (PP) (Sample C) was used.

  Samples A to C were struck and given vibration to generate dust. And the dust which generate | occur | produced from each was observed with the optical microscope. The dusts generated from the samples A to C were all in a fibrous shape, and the fiber lengths thereof were a sample A: 1450 to 1900 μm, a sample B: 130 to 430 μm, and a sample C: 100 to 280 μm.

  From the above results, it can be seen that the dust generated from the samples A to C is a fiber constituting each nonwoven fabric. Moreover, it turns out that the fiber length of a cellulose nonwoven fabric (sample A) is longer than the fiber length of a synthetic resin nonwoven fabric (samples B and C). Therefore, the dust generated from the cellulose-based nonwoven fabric (sample A) is less likely to adhere to the substrate surface than the dust generated from the synthetic resin-based nonwoven fabric (samples B and C). It is considered that it can be removed and is not easily fixed.

DESCRIPTION OF SYMBOLS 1 Storage case 2 Case main body 3 Lid 4 Packing body 5 Squeeze part 10 of a press machine Synthetic quartz glass substrate 11, 12, 13, 14, 15 for photomasks Measurement position 21 on board | substrate 22 Bottom plate 22 1st side wall 23 2nd side wall 24鍔 25 fitting portion 26 elastic member 27 support member 31 upper plate 32, 33 lid side wall 34 鍔 37 tube 41 cellulosic nonwoven fabric 42 adsorbent

Claims (10)

A method of storing a synthetic quartz glass substrate for photomask or a photomask blank,
Preparing a storage case;
Installing an adsorbent packaged in a cellulose-based nonwoven fabric inside the storage case;
A method for storing a synthetic quartz glass substrate for photomask or a photomask blank, comprising storing the synthetic quartz glass substrate or photomask blank for photomask in the storage case.
The method for storing a synthetic quartz glass substrate for a photomask or a photomask blank according to claim 1, wherein the cellulose-based nonwoven fabric has a bag shape.
The synthetic quartz glass substrate or photomask blank storage method according to claim 2, wherein the cellulose-based nonwoven fabric is processed into a flat bag shape by pressing.
The method for storing a synthetic quartz glass substrate for a photomask or a photomask blank according to any one of claims 1 to 3, wherein the adsorbent is activated carbon.
The fiber length of the cellulose fiber contained in the said cellulose nonwoven fabric is 500 micrometers-5000 micrometers, The storage method of the synthetic quartz glass substrate for photomasks or photomask blanks as described in any one of Claim 1 to 4.
The method for storing a synthetic quartz glass substrate for a photomask or a photomask blank according to any one of claims 1 to 5, wherein the storage case is a storage case formed by welding a synthetic resin with an organic solvent.
The synthetic quartz glass substrate for photomask according to any one of claims 1 to 6, wherein the synthetic quartz glass substrate or photomask blank for photomask is a rectangular plate-like body having a short side of 300 mm or more and a long side of 400 mm or more. Or photomask blank storage method.
The storage case is
A bottom plate, a pair of first side walls connected to the bottom plate and facing each other, and a pair of second side walls connected to the bottom plate and connecting the first side walls, facing each other, facing the bottom plate A box body whose upper surface is opened, and a case main body for storing the synthetic quartz glass substrate for photomask or a photomask blank,
A storage case comprising a lid that covers the opening and is detachably attached to the case body,
The adsorbent wrapped with the cellulose-based nonwoven fabric is installed on the surface of the first side wall inside the case body,
The photomask for photomask according to any one of claims 1 to 7, wherein the synthetic quartz glass substrate for photomask or the photomask blank is housed inside the case body, with an end face thereof supported by the second side wall. Storage method of synthetic quartz glass substrate or photomask blank.
The photomask which conveys in the state which stored the said synthetic quartz glass substrate for photomasks, or the photomask blank by the storage method of the synthetic quartz glass substrate for photomasks or the photomask blank as described in any one of Claims 1-8. For transporting synthetic quartz glass substrates or photomask blanks.
A storage case for a synthetic quartz glass substrate or a photomask blank for a photomask,
A storage case of a synthetic quartz glass substrate for a photomask or a photomask blank in which an adsorbent packaged with a cellulose-based nonwoven fabric is installed inside the storage case.

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