JP2007091296A - Mask blank storage container, storing method of mask blank and stored body of mask blank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mask blank storage container which prevents contamination by a foreign matter such as a chemical material accompanying the ingress of exterior air, stores a mask blank, etc. keeping a clean atmosphere and prevents the ingress of exterior light. <P>SOLUTION: This storage container provided with a container main body with an open top and a lid to cover the main body stores inside a mask blank having a resist film. A vent hole is formed in the corner of the lid to let exterior air through, and a filter member 6 is mounted on the vent on the container inner side. When exterior air comes in through the vent, a foreign matter such as a chemical material contained in the air is removed by the member 6. When exterior light comes in from the vent, the filter member 6 prevents the light from coming into the container by shifting the optical path not to be linear in the member 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a photomask used for manufacturing an electronic device, a container for storing a mask blank used for manufacturing the photomask, and a method for storing the same.

  In recent years, electronic devices, particularly color filters or TFT elements for semiconductor elements and liquid crystal monitors, are required to be further miniaturized with the rapid development of IT technology. One of the technologies that support such a fine processing technology is a lithography technology using a photomask called a transfer mask. In this lithography technique, a fine pattern is formed on a silicon wafer by exposing an electromagnetic wave or light wave of an exposure light source to a silicon wafer with a resist film through a transfer mask. This transfer mask is usually manufactured by forming a pattern serving as an original plate using a lithography technique on a mask blank in which a light-shielding film is formed on a light-transmitting substrate. By the way, if there is a foreign substance such as a particle on the surface of the mask blank, it will cause a defect in the pattern to be formed. Therefore, it is necessary to store it cleanly so that the foreign substance or the like does not adhere to the surface of the mask blank.

As a container for storing, transporting and transporting such a mask blank, a mask transport case as described in, for example, the following Patent Document 1 is conventionally known.
That is, a conventional container for storing and storing a mask blank has an inner case called a carrier or the like in which several to several tens of mask blanks are arranged and held, and the inner case holding the mask blank is placed in an outer box (case main body). ) And a cover on the outer box to accommodate the mask blank. And by sticking an adhesive tape on the junction part of an outer box and a lid | cover, while sealing a case, it was trying to prevent entrance of external air, a foreign material, etc.
JP 2001-154341 A

As the performance of electronic devices in recent years has increased, the pattern formed on the transfer mask is also required to be further miniaturized. In order to form such a miniaturized pattern, the cleanness of the mask blank is extremely high. Otherwise it will be unacceptable. Therefore, it is necessary to maintain the cleanliness as high as possible, particularly during storage of the mask blank, by suppressing as much as possible foreign matter from adhering to the mask blank.
Recently, a chemically amplified resist has attracted attention as a resist for a photomask. This chemically amplified resist is described in, for example, Japanese Patent Application Laid-Open No. 2000-66380. Since this chemically amplified resist is superior in characteristics such as sensitivity and contrast as compared with conventional photoresists, it can be said that it is advantageous for forming a miniaturized pattern. However, it has been pointed out that this chemically amplified resist is susceptible to chemical component contamination due to its reaction mechanism. That is, if there is contamination of a certain kind of chemical component, the function of a substance serving as a catalyst for a chemical amplification reaction is suppressed or inhibited (for example, deactivated), and desired performance may not be obtained. For this reason, in the case of a mask blank with a chemically amplified resist film, it is not necessary to simply remove foreign substances such as particles, and it is necessary to store in a particularly clean atmosphere in order to eliminate the influence of chemical component contamination. There is.

In conventional mask blank storage containers, for example, the joint between the outer box and the lid was sealed with adhesive tape, but the tape was affixed when the mask blank was stored and packed, and the tape was peeled off when opened. In addition to the time and effort, the sealed state was not perfect. That is, in the case of a commonly used adhesive tape, since it has some air permeability, the inside air may expand or contract depending on the temperature change of the atmosphere in which the storage container is stored. The entrance and exit between the outside air and the inside air occurs through the joint portion to which the tape is applied. In addition, the atmospheric pressure may fluctuate as in the case of carrying a mask blank on an aircraft. When transported by aircraft, the change in atmospheric pressure becomes considerably large, and thus ventilation between the outside air and the inside air occurs at this time. Therefore, even if the mask blank is stored and packed in a container in a clean atmosphere such as a clean room, depending on the subsequent storage atmosphere, the outside air enters over time, and the inside of the storage container is caused by some component contained in the outside air. May be contaminated.
Furthermore, even if a plastic or the like that does not easily release any chemical component is used as the material of the storage container, the chemical component used in the base material or adhesive of the adhesive tape enters the storage container over time. May be contaminated. In particular, when there is a change in the atmosphere such as the above-described temperature change or atmospheric pressure change, there is a risk that contamination by chemical components generated from the tape will accelerate.

In particular, in the case of the mask blank on which the above-described chemically amplified resist film is formed, contamination due to contamination of chemical components and the like becomes a fatal defect and must be avoided absolutely.
Thus, the method of storing and packing the mask blank in a container in a clean room or the like, and sealing the joint between the outer box and the lid with the adhesive tape at first glance prevents the outside air from entering and cleans the mask blank. Although it seems that it can be stored in an atmosphere, it was actually difficult to avoid contamination due to the ingress of outside air or chemical components of the adhesive tape.

Therefore, one of the applicants of the present application has first solved such problems and provided a means for preventing foreign matter in the outside air from entering the storage container, thereby providing a chemical substance accompanying the entry of the outside air. A storage container that can prevent contamination by foreign matters such as mask blanks and keep a mask blank while maintaining a clean atmosphere has been proposed (Japanese Patent Laid-Open No. 2005-43796). Means for preventing foreign matter in the outside air from entering the storage container includes a vent hole provided in the storage container and a filter member for removing foreign matter in the external air provided in the vent hole. In addition, the storage container for storing and storing the mask blank having the resist film needs to be made of a light-shielding material, but when the present inventors provide such a filter member, external light is transmitted from the vent hole. As a result of further studies from the viewpoint that it is necessary to prevent the filter member from passing through the inside of the storage container, certain findings were obtained.
The present invention relates to a mask blank storage container and storage method capable of preventing contamination by foreign substances such as chemical substances accompanying the entry of outside air, storing mask blanks while maintaining a clean atmosphere, and preventing entry of outside light, and An object is to provide a mask blank container.

In order to solve the above-mentioned problems, the present invention has the following configuration.
(Configuration 1) A mask blank storage container that includes at least a container main body and a lid that covers the container main body, and stores the mask blank therein, and prevents foreign matter in the outside air from entering the storage container. A mask blank storage container comprising filter means and means for preventing external light from passing through the filter means and entering the storage container.
(Structure 2) The mask blank storage container according to Structure 1, wherein the optical path through which the external light passes through the filter means and enters the storage container is not linear.
(Configuration 3) The mask blank storage container according to Configuration 1 or 2, wherein an end portion of the filter means facing inward of the storage container is covered with a light shielding member.
(Configuration 4) The filter means includes a vent hole for outside air and inside air provided in the storage container, and a filter member for removing foreign matter in the outside air provided in the vent hole. It is a mask blank storage container as described in any one of thru | or 3.
(Structure 5) A mask blank storage method comprising storing a mask blank having at least one resist film in the mask blank storage container according to any one of Structures 1 to 4.
(Structure 6) A mask blank storage body comprising the mask blank storage container according to any one of structures 1 to 4 and at least one mask blank stored in the storage container. .
(Structure 7) The mask blank container according to Structure 6, wherein the mask blank is a mask blank having a resist film.

  According to the present invention, in the mask blank storage container provided with the container body opened at the top and the lid body covering the container body, as a filter means for preventing foreign matter in the outside air from entering the storage container, For example, by providing a vent hole for outside air and inside air in the storage container and at the same time providing a filter member for removing foreign matter in the outside air, the outside air can be prevented from entering the storage container during storage. Therefore, it is possible to effectively prevent foreign matter in the outside air, for example, particles or some chemical substance contained in the outside air from entering the storage container and contaminating the mask blank. That is, even when outside air enters the storage container during storage, foreign substances such as chemical substances contained in the outside air are removed and cleaned by the filter member, and the inside of the storage container is cleaned by cleaning the outside air. The mask blank can be stored for a long period of time while being kept in a clean atmosphere. Moreover, according to the present invention, it is possible to prevent external light from passing through the filter means and entering the storage container. For this reason, it is possible to prevent the mask blank from being contaminated with foreign substances such as chemical substances during storage, and the resist film of the mask blank from being exposed to the entry of external light. The transfer mask can be obtained.

The best mode for carrying out the present invention will be described below with reference to the drawings.
5 to 8 show an embodiment of a mask blank storage container according to the present invention. FIG. 5 is a perspective view showing a cover of the storage container, and FIG. 6 shows a state in which the mask blank is stored in an inner case. FIG. 7 is a perspective view showing a container main body (outer case) of the storage container, and FIG. 8 is a longitudinal sectional view of the storage container in which a mask blank is stored.
The storage container of the present embodiment is a mask blank 1 in which a light-shielding thin film such as a chromium film is formed on one main surface of a glass substrate having a square main surface, and the above-described chemically amplified resist film is formed thereon, for example. Is housed in the middle case 2, the middle case 2 is housed in the container body 3, and the lid 4 is put on the opening side of the container body 3 (see FIG. 8).
Note that the mask blank 1 may be directly stored in the container body 3 with a groove or the like without using the middle case 2. However, if the middle case 2 is used as in the present embodiment, it is convenient because several to several tens of mask blanks can be handled together in the middle case 2. In this case, when storing a plurality of mask blanks, the mask blanks are preferably set in the vertical direction or the inclined direction. Further, when storing one mask blank, it is preferable to store the mask blank in a horizontal direction in a case containing one mask blank.

  In the middle case 2 of the present embodiment, a plurality of grooves 21 and 22 are formed from the opening side (upper side) to the bottom side (lower side) as a pair with one predetermined inner surface facing each other. Opening windows 23 and 24 and an opening 27 are provided on the bottom of the grooves 21 and 22 and the bottom of the middle case, respectively, and a substrate support 26 is formed on the bottom of the middle case. 26 supports the lower end face of the mask blank 1 (see FIGS. 6 and 8). Then, concave surface portions 28 and 29 for accommodating and fixing the middle case 2 in the container body 3 are formed on the other opposite outer surfaces of the middle case from the bottom surface side to the middle of the opening portion side ( (See FIG. 6). Note that the height dimension from the upper end surface 25 on the opening side of the middle case 2 to the substrate support portion 26 corresponds to the main part of the height dimension of the mask blank 1 to be accommodated. When stored, the upper part of the mask blank 1 protrudes from the upper end surface 25 of the middle case 2 (see FIG. 8). When several mask blanks 1 are inserted along the pair of grooves 21 and 22 of the middle case 2, these mask blanks stand in parallel with each other at a predetermined interval. In this embodiment, forests are formed in the vertical direction, but may be inclined.

The container body 3 of the present embodiment is formed with protrusions 31 and 32 adapted to abut against the concave portions 28 and 29 of the middle case 2 described above on the inner surfaces facing each other, and the bottoms of the protrusions 31 and 32. Is also joined to the bottom surface of the container body 3 (see FIG. 7). In addition, convex portions 33 and 34 are formed on the opening side of one opposing outer surface. The outer peripheral surface 36 following the position slightly below the opening edge 35 of the container body 3 and the convex surfaces of the convex portions 33 and 34 are formed on substantially the same plane.
The lid 4 according to the present embodiment has recesses in engagement pieces 41 and 42 extending from one opposing lower edge (the edge on the opening side to be inserted into the container body and facing upward in FIG. 5) 47. 43 and 44 are formed. Accordingly, when the lid 4 is put on the container body 3, the concave portions 43 and 44 are engaged with the convex portions 33 and 34 of the container main body 3, so that the lid 4 and the container main body 3 are fixed. (See FIG. 8). Further, stoppers 45 and 46 which are in contact with the upper end surface 25 on the opening side of the middle case 2 and support and fix the middle case 2 in the vertical direction are formed on one inner surface so as to face each other (see FIG. 5). In addition, it is good also as a structure which can cover the lid | cover 4 as it is, without providing the recessed parts 43 and 44 of the lid | cover 4, and the convex parts 33 and 34 of the container main body 3. FIG. Further, even when the concave portion of the lid 4 and the convex portion of the container main body 3 are engaged, such engaging means may be formed not only on one side facing each other but also on each of the four sides.

The material of the above middle case 2, the container main body 3, and the lid | cover 4 is suitably selected from resin, such as a polypropylene, an acryl, polyethylene, a polycarbonate, polyester, polyamide, a polyimide, a polyethyl sulfite, for example. Among these, polycarbonate or polyester is preferable. The material of the container body 3 and the lid 4 is preferably polycarbonate, and the material of the middle case 2 is preferably polyester. As this polyester, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and the like are preferable. Further, a copolymer resin (ABS resin) of acrylonitrile, butadiene and styrene can be preferably used. In addition, if a charge is accumulated during the storage of the mask blank, it may cause a discharge breakdown in the mask manufacturing process, resulting in a pattern defect. For example, carbon or the like is mixed into the constituent resin of the container body 3 to provide conductivity. It is preferable.
When the lid 4 is put on the container body 3 and the recesses 43 and 44 of the lid 4 are engaged with the projections 33 and 34 of the container body 3 to fix the lid 4 and the container body 3, the lower edge of the lid 4 The outer peripheral surface 48 that follows and the outer peripheral surface 36 that follows the opening edge of the container main body 3 are overlapped and joined in the front-rear direction.

In the present embodiment, a vent hole 49 for outside air and inside air is formed at one corner of the lid 4, and the filter member 5 is attached to the vent hole 49 toward the inside of the lid 4 ( (See FIGS. 5 and 8). The filter member 5 has a configuration in which pipes 51 and 53 that are gas flow paths are integrally formed on both sides of a bowl-shaped filter holding portion 52 that holds a filter therein. The 51 side is attached to the vent hole 49 of the lid 4, and the pipe 53 side is directed inward of the lid 4. The filter holding part 52 can be divided, and is configured so that an internal filter can be attached and detached. In addition, the corner part of the lid | cover 4 which provided the vent hole 49 is dented inward, and the said filter holding part 52 is made to contact | abut on the concave surface.
Therefore, even when outside air enters through the vent hole 49 in a state where the mask blank is stored and stored in the storage container according to the present embodiment, foreign substances such as chemical substances contained in the outside air are removed by the filter member 5. Since only the clean outside air enters the container as it is, the cleanliness inside the container is maintained.

  By the way, FIG. 10 shows a cross-sectional view of the filter member 5 described above. When the light path from outside air through the filter member 5 to the inside of the storage container is straight, Light may enter the interior of the storage container. In this case, a filter 54 is mounted inside the filter member 5, and light may be transmitted through the filter 54. Although it is possible to block light in a specific wavelength range depending on the material of the filter 54, it is not always possible to completely block the photosensitive wavelength range of the resist film on the mask blank.

  Therefore, in the present invention, the filter member has a structure as shown in FIG. In other words, FIG. 1 is a cross-sectional view showing an embodiment of a filter member used in the present invention. According to this, the filter member 6 has a bowl-shaped filter holding portion 62 that holds a filter therein. The pipes 61 and 63, which are gas flow paths, are integrally formed on both sides at positions different from the corresponding positions, and the inner hole 61a of the pipe 61 and the inner hole 63a of the pipe 63 are held by the filter. It communicates via the gap 62c of the section 62 so that the outside air and the inside air can be ventilated. For example, the pipe 61 side is attached to the vent hole 49 of the lid 4, and the pipe 63 side is directed inward of the lid 4. Further, the filter holding portion 62 can be divided into a portion 62a and a portion 62b so that the internal filter 64 can be attached and detached. The material of the filter member 6 is not particularly limited as long as it is a material capable of shielding light, but can be formed of, for example, polypropylene (PP), polymethyl methacrylate (PMMA), or the like.

According to the filter member 6 configured in this manner, the optical path through which the external light passes through the filter member 6 from the vent hole 49 of the lid 4 and enters the inside of the storage container is shifted so as not to be linear. Without causing any trouble in the ventilation of the light, for example, light entering from the pipe 61 side is blocked in the filter member 6 due to the straightness of light, so that the light path from the pipe 63 side further enters the storage container. Can be blocked.
FIG. 2A is an external perspective view of the filter member 6. 2 (b) and 2 (c) show other embodiments of the filter member 6, respectively. FIG. 2 (b) shows that the pipe 64 and the pipe 65 on both sides of the filter holding part 62 are the same. FIG. 5C shows a configuration formed integrally with the filter holding portion 62, with the pipes 66 and 67 on both sides thereof inclined diagonally to the opposite side. ing. According to other embodiments of these filter members, it is possible to suitably prevent the outside light from entering the storage container by shifting the optical path so as not to be linear.

Moreover, you may make it cover the edge part which turned to the storage container of the said filter member with the light shielding member. For example, a cap member 7 as shown in FIG. 3 can be used. 3A shows a cap member having a structure having two circular holes 72 and 73 drilled in parallel to each other inside the bowl-shaped main body 71, and FIG. 3B shows the cap member of the bowl-shaped main body 71. The cap member of the structure which has the two circular holes 74 and 75 drilled mutually diagonally inside is shown. The one shown in (a) is suitable for covering the filter member of FIG. 2 (a), and the one shown in (b) is suitable for covering the filter member of FIG. 2 (b) and (c). Is preferred.
In the case of the filter member 5 having the structure shown in FIG. 10 as described above, as shown in FIG. 4, a light shielding material (for example, covering the end of the pipe 53 facing the inside of the storage container of the filter member 5) A cap member 8 made of PMMA or the like may be covered. This also makes it possible to suitably prevent external light from entering the storage container. In this case, the cap member 8 may be covered from the pipe 53 side of the filter member 5 as shown in FIG. 4A, or the filter member 5 as shown in FIG. 4B. The cap member 8 may be covered from the pipe 51 side.

  In addition, as a filter used for the said filter member 6, the air filter normally used in a clean room can be used, for example. Preferred examples of such a filter include a HEPA filter (high efficiency particulate air filter) and a ULPA filter (ultra low penetration particulate air filter). The HEPA filter is a high-efficiency air filter that is mainly used for air purification in a clean room, and is mainly made of glass fiber. The ULPA filter is an ultra-high performance filter developed along with the miniaturization of VLSI manufacturing, and is mainly made of glass fiber or fluorine resin. The filter is preferably a filter that can capture particles of 0.05 μm or more. The selection of an air filter such as a HEPA filter or a ULPA filter can be appropriately selected in consideration of cost effectiveness. In practice, a HEPA filter can be used.

In addition, when storing and storing a mask blank having a chemically amplified resist film that needs to eliminate contamination by chemical substances, a filter (chemical filter) that adsorbs chemical substances is used alone or in combination with the air filter. It is preferable. As such a chemical filter, for example, an activated carbon filter or an ion exchange filter can be preferably used. The selection of a chemical filter such as an activated carbon filter or an ion exchange filter can be appropriately selected in consideration of cost effectiveness. In practical use, an activated carbon filter can be used.
Such chemical amplification resist is contaminated, that is, the desired chemical amplification effect of the chemical amplification resist is inhibited (the chemical amplification effect is enhanced or suppressed as compared with the desired, and a predetermined resist pattern is formed. Examples of chemical substances to be removed include acidic chemical substances and basic chemical substances. Examples of acidic chemical substances include substances containing chlorine ions, substances containing sulfate ions, substances containing phosphate ions, substances containing nitrate ions, and the like. In addition, examples of the basic chemical substance include nitrogen-containing compounds such as ammonia, amines, anilines, and nitriles that suppress or inhibit (for example, deactivate) the function of an acid serving as a catalyst for a chemical amplification reaction.
The resin for the filter is more preferably black from the viewpoint of light shielding.

  As described above, according to the storage container of the present invention, even if the outside air enters from the vent hole 49 during storage and storage of the mask blank or the like, foreign substances such as chemical substances contained in the outside air are filtered out by the filter member 6. (5) prevents entry into the container, so it can be stored while maintaining the clean atmosphere when the mask blank is stored for a long period of time, and outside air enters the container as it is and is included in it. There is no risk of being contaminated by foreign substances such as chemical substances. Therefore, the present invention is suitable for storing and storing a mask blank having a chemically amplified resist film that is easily affected by the environment in which it is stored and that is required to be stored in a clean atmosphere. Moreover, according to the storage container of the present invention, even if external light enters the filter member from the vent hole, it is possible to prevent the light from passing through the filter member and entering the storage container. Further, it is possible to prevent the resist film of the mask blank from being exposed by the entry of external light.

It should be noted that the joint between the lid 4 and the container body 3, that is, the outer circumferential surface 48 that follows the lower edge of the lid 4 when the lid 4 is placed on the container body 3 and the outer circumferential surface 36 that follows the opening edge of the container body 3 In general, it is conceivable that the outside air enters from the joint portion overlapped with each other. However, as in the present embodiment, the vent hole 49 is provided in the container so that even if outside air enters, the air hole 49 is preferential. Therefore, contamination in the container can be sufficiently prevented.
Further, in the present embodiment, the vent hole 49 and the filter means 6 (5) are provided at one corner of the lid 4, but there is no need to be limited to this, and it does not contact the mask blank or the like to be stored. If it is such a place, it may not be a corner and may be provided in a plurality of places instead of one place. Moreover, you may provide in the container main body 3 side instead of the top plate of the lid | cover 4 like this embodiment.

FIG. 9 shows another embodiment of a mask blank storage container according to the present invention, which is a case containing one mask blank that can be stored and stored in the horizontal direction.
The mask blank storage container 100 is roughly divided into two members, that is, a lid 101 and a main body case 102, and one rectangular mask blank 1 is stored horizontally in the interior.
The lid 101 is formed in a rectangular shape as a whole in accordance with the shape of the mask blank to be stored, and the lower side is open. On one side of the upper surface of the lid 101 facing each other, the flanges 103 and 103 are extended integrally with the lid 101 so as to extend in the horizontal direction so as to be convenient for lifting the lid 101 by hand. Further, the above-described filter member 6 is attached to an inner corner of the lid 101. On the other hand, the main body case 102 is formed in a square shape that is slightly larger than the lid 101. The lid 101 and the main body case 102 are provided with a fixing member 106 rotatably held by two left and right hinge plates 105, 105 formed integrally on the side wall of the lid 101 in a notch (recessed portion) 104 of the main body case 102. By being fitted, it can be fixed integrally.

  Even in the storage container 100 of the present embodiment, foreign substances such as chemical substances contained in the outside air are brought into the container by the filter member 6 even if the outside air enters through the vents during storage and storage of the mask blank or the like. Since the entry is blocked, it is possible to store the mask blank while maintaining the clean atmosphere as it is for a long time. In addition, even if external light enters the filter member 6 from the vent hole, it is possible to prevent the light from passing through the filter member 6 and entering the storage container. It is possible to prevent exposure due to the entry of external light.

The mask blank to which the present invention is applied is a mask blank in which a light-shielding film such as Cr is formed on a light-transmitting substrate such as a glass substrate, and a phase in which a halftone (semi-transparent) film is formed on the substrate. A mask blank for a shift type mask, a mask blank for a reflective mask in which, for example, a Mo / Si multilayer reflective film that reflects exposure light and a Ta-based absorber film that absorbs exposure light are formed on the substrate are included. . The present invention is particularly suitable for storing and storing a mask blank having a resist film. Needless to say, the present invention is not limited to a square mask blank or the like, but can be applied to other shapes such as a disc-shaped substrate.
Hereinafter, the present invention will be described with reference to specific examples.

On a quartz substrate (size 152 mm × 152 mm), a light-shielding film made of chromium (Cr) was formed to a thickness of 1000 mm by a sputtering method using a chromium target. Next, a resist film was formed on the light-shielding film by a spin coating method to a thickness of 5700 mm to manufacture a mask blank with a resist film. As the resist, a positive resist THMR-IP1700 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used.
100 mask blanks manufactured in this way were stored separately in 10 storage containers of the embodiment shown in FIGS. The lid and container body were made of polycarbonate, and the middle case was made of polybutylene terephthalate. Moreover, the filter member 6 of embodiment shown in above-mentioned FIG. 1 was used for the filter member attached to a container. Moreover, as a filter with which this filter member 6 is mounted | worn, the activated carbon filter and the HEPA filter were used in combination. The storing operation was performed in a clean room cleaned with an activated carbon filter and a ULPA filter.

  This storage container was further packed in a packing bag, and cargo was transported by aircraft. Then, the transported storage container was opened in a clean room similar to the above, and a predetermined electron beam was drawn on the taken-out mask blank, followed by predetermined development and etching to manufacture a transfer mask. When the quality of the manufactured transfer mask was inspected in detail with a scanning electron microscope, no particularly problematic defect was found from any of the 100 sheets.

(Comparative example)
In the embodiment described above, a storage container (lid) with a filter member having a structure shown in FIG. 10 (using a light path in which the external light passes through the filter member 5 and reaches the inside of the storage container is linear) The mask blank was manufactured, stored, and transported in the same manner as in Example except that the same material as in Example was used).
When the quality of the transfer mask manufactured in the same manner as in the example using the mask blank after transportation was inspected in detail with a scanning electron microscope, the resist film was exposed to light before pattern drawing on some masks. It was discovered that the line width of the pattern was disturbed due to what was happening. This is presumably because the light of the fluorescent lamp in the clean room passes through the filter member from the vent of the storage container and enters the inside, and the resist film of the mask blank is exposed.

It is sectional drawing which shows one Embodiment of the filter member used for this invention. It is an external appearance perspective view which shows one Embodiment of the filter member used for this invention, and other embodiment. It is an external appearance perspective view which shows one Embodiment of the cap member used for this invention, and other embodiment. It is sectional drawing explaining the case where a filter member covers and uses a cap member. It is a perspective view which shows the cover of the storage container which concerns on one embodiment of this invention. It is a perspective view which shows the state which accommodates a mask blank in a middle case. It is a perspective view which shows the container main body (outer case) of the said storage container. It is sectional drawing of the vertical direction of the state which accommodated the mask blank in the said storage container. It is an external appearance perspective view of the storage container which concerns on other embodiment of this invention. It is sectional drawing of a filter member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mask blank 2 Middle case 3 Container body 4 Lid 5, 6 Filter member 7, 8 Cap member 49 Vent

Claims (7)

A mask blank storage container that includes at least a container main body and a lid that covers the container main body, and stores a mask blank therein,
A filter means for preventing foreign matter in the outside air from entering the storage container, and means for preventing external light from passing through the filter means and entering the storage container are provided. Mask blank storage container.   2. The mask blank storage container according to claim 1, wherein an optical path through which external light passes through the filter means and enters the storage container is not linear.   The mask blank storage container according to claim 1 or 2, wherein an end portion of the filter means facing inward of the storage container is covered with a light shielding member.   4. The filter means according to claim 1, wherein the filter means comprises a vent hole for outside air and inside air provided in the storage container, and a filter member for removing foreign matter in the outside air provided in the vent hole. The mask blank storage container as described in any one.   5. A mask blank storage method comprising storing a mask blank having at least one resist film in the mask blank storage container according to claim 1.   A mask blank storage body comprising the mask blank storage container according to any one of claims 1 to 4 and at least one mask blank stored in the storage container. The mask blank storage body according to claim 6, wherein the mask blank is a mask blank having a resist film.

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