JP2010113202A - Mask storage container and opening method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mask storage container capable of storing a pattern transfer mask while keeping the inner cleanliness to an extremely low value. <P>SOLUTION: The mask storage container 100 for storing a reticle 107 includes an outer dish 101 and an outer lid 103 to be joined with the outer dish 101 so as to form an inner sealed space 100a, wherein the mask storage container 100 includes: an inner lid 104 and an inner dish 102 forming a mask space 100b for storing the reticle 107 inside the sealed space 100a, when the outer lid 103 and the outer dish 101 are joined; and an encapsulation port 111 with a check valve for introducing a gas having a lower cleanliness than a predetermined cleanliness into the mask space 100b when the outer lid 103 is disengaged from the outer dish 101 of the mask storage container 100 storing the reticle 107. By this configuration, the reticle 107 can be stored while keeping the inner cleanliness to an extremely low value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mask container for a pattern transfer mask (a member for manufacturing a semiconductor device such as a photomask) associated with a product and a process in a semiconductor process.

  2. Description of the Related Art Conventionally, a mask storage container for storing a pattern transfer mask used in a photolithography technique includes an outer plate made of plastic and an outer lid. The outer plate is provided with a holder for holding the pattern transfer mask, and the pattern transfer mask stored in the mask storage container is held with the pellicle surface of the pattern transfer mask facing down. .

  The pellicle is a pattern protective film attached to a semiconductor device pattern (hereinafter referred to as a pattern), and prevents foreign matters such as dust from adhering to the pattern surface. This pellicle prevents the defective pattern corresponding to the pattern to which foreign matter has adhered from being transferred onto the wafer, thereby improving the productivity of the semiconductor device.

  However, the pattern surface of the pattern transfer mask has been miniaturized in recent years, and the pattern surface is easily contaminated. For example, as compared with a conventional pattern surface, a miniaturized pattern surface is easily affected by static electricity and minor foreign matter. Therefore, the pattern surface of the pattern transfer mask stored in the above-described mask storage container is easily destroyed by static electricity, or the pattern surface of the pattern transfer mask is easily attached due to the adhering of a small amount of foreign matter. Contaminated. Such a problem causes a decrease in product quality and yield in the semiconductor manufacturing process.

  One of the causes of the above-described destruction of the pattern surface due to static electricity and the contamination of the pattern surface due to the attachment of foreign matter is becoming clear in the mask storage container for storing products, semiconductor wafers, and pattern transfer masks. In other words, by performing the configuration and design of the mask storage container and the accompanying function control of the mask storage container, it is possible to prevent the destruction and contamination of the pattern surface described above and improve the quality and yield of the semiconductor device product. It is.

  In order to solve the above-described problem, Japanese Patent Laying-Open No. 2001-253491 (Patent Document 1) discloses a semiconductor device having a bottom plate on which a member for manufacturing a semiconductor device is placed and an upper lid that covers the bottom plate. A technique for improving the storage and carrying case of the manufacturing member is disclosed.

  FIG. 8 is a cross-sectional view showing the structure of the housing and transport case for the semiconductor device manufacturing member described in Patent Document 1. As shown in FIG. 8, the bottom plate 811 of the storage and transport case 810 is provided with a reticle holding body 813 on which a reticle 812, which is a pattern transfer mask used in the reduction projection exposure apparatus, is floated and placed. ing. The reticle 812 is placed on the reticle holder 813 with its glass surface 814 facing up and the pellicle surface 815 on which the pattern is formed facing down. The reticle 812 placed on the bottom pan 811 via the reticle holder 813 is sealed in the storage and transport case by bringing the top lid 816 into contact with the bottom pan 811. To bring the upper lid 816 into contact with the bottom plate 811 is to bring all the lower surfaces of the peripheral portion of the upper lid 816 into contact with the upper surface of the bottom plate 811. When the entire lower surface of the peripheral edge of the upper lid 816 is brought into contact with the bottom plate 811, there is no gap between both surfaces, and an internal space 810 a sealed in the storage and transport case 810 is formed.

  When the sealed storage and transport case 810 is opened, the bottom tray 811 of the storage and transport case 810 is configured to descend from the top lid 816 and to remove the top lid 816 from the bottom tray 811.

In this storage and transport case 810, the material of the bottom plate 811 is formed of polycarbonate added with carbon, and the material of the top lid 816 is formed of non-conductive plastic, so that foreign matter adheres to the pattern surface of the reticle 812. This can be suppressed, and the device patterns can be prevented from being destroyed by static electricity.
JP 2001-253491 A.

  By the way, along with the above-mentioned pattern miniaturization, in order to prevent contamination of the pattern surface by foreign substances, there is an increasing demand for cleaning peripheral devices surrounding the exposure apparatus, and irradiation from the light source of the exposure apparatus. The demand for using light having a shorter wavelength as the wavelength of the emitted light is also increasing.

  As a technique using light having a shorter wavelength, EUVL (Extreme Ultra Violet) using light having an extremely short wavelength of 13.5 nm as compared with the wavelength of ultraviolet light can be mentioned. This EUVL is a technique that can divert a method according to the reduction projection exposure technique, and is a technique that shortens the wavelength of light to the limit. The manufacture of semiconductor devices employing such a technique is expected to start mass production in 2009.

  This EUVL has a problem that arises from the feature that the wavelength of light is extremely short. For example, in a wavelength region corresponding to a light wavelength of 13.5 nm, there is no lens material for refracting the light to diffuse or focus it. Therefore, in EUVL, the refractive lens from the prior art cannot be used, and a multilayer reflector must be used. The reflectance of this multilayer-film reflective mirror is about 67% for light with a wavelength of 13.5 nm, and the intensity of light is attenuated by repeated reflection, so that the light cannot pass through the pellicle surface. There is a problem. Therefore, the reticle used in EUVL cannot use a pellicle that is a pattern protection film against foreign matter, and the cleanliness in the storage and transport case is very low in order to prevent foreign matter from adhering to the pattern surface. It is necessary to keep the value. Note that a low degree of cleanliness of a space indicates that the space is clean.

  However, in the storage and transport case 810 of Patent Document 1 shown in FIG. 8, by repeatedly opening and closing the storage and transport case 810, the contact surface between the entire lower surface of the peripheral portion of the upper lid 816 and the upper surface of the bottom plate 811 is worn. Foreign matter is inevitably generated from the storage and transport case 810 itself. Furthermore, since the internal space 810a configured by the upper lid 816 and the bottom plate 811 of the storage and transport case 810 is sealed, the volume of the internal space 810a of the storage and transport case 810 expands when the storage and transport case 810 is opened. The state where the atmospheric pressure of the internal space 810a of the storage and transport case 810 temporarily becomes lower than the atmospheric pressure occurs. This state is called a negative pressure state. In the negative pressure state, since the internal space 810a draws external air from between the above-described upper lid 816 and the bottom plate 811, the foreign matter generated on the contact surface is also drawn with the air, and the internal space 810a becomes a foreign matter. Will be contaminated. Since the foreign matter mixed in the storage / transport case 810 can easily adhere to the pattern surface of the reticle 812, as a result, the storage / transport case 810 of Patent Document 1 prevents the foreign matter from adhering to the pattern surface of the reticle 812. There is a problem that it cannot be done. In particular, when storing an EUVL reticle in which a pellicle that is a pattern protective film cannot be used, the above-described problem appears more remarkably.

  Accordingly, the present invention has been made to solve the above problems, and provides a mask storage container capable of storing a pattern transfer mask while keeping the internal cleanliness value very low. The purpose is to do.

  In order to solve the above-described problems and achieve the object, a mask storage container according to the present invention includes an outer plate and an outer lid that fits with the outer plate so as to form a sealed space therein, and the sealed space. And a mask storage container for storing a pattern transfer mask.

  The pattern transfer mask is a member for manufacturing a semiconductor device such as a photomask, and for example, a reticle used in a reduction projection exposure apparatus can be adopted. The reticle may or may not include a pellicle.

  The outer plate and the outer lid may have any shape as long as they form a sealed space when the outer lid and the outer plate are combined. For example, the outer plate is a pattern transfer mask to be stored. It is possible to adopt a square or rectangular plate-like object in plan view having an area larger than the area of the pattern surface. Further, for example, the outer lid has a square or rectangle in a plan view having an area larger than the area of the pattern surface of the pattern transfer mask to be accommodated, and a lid having a reverse concave shape in the front view is adopted. be able to. When the outer lid is placed on the outer plate, the entire lower surface of the peripheral edge of the outer lid is in contact with the upper surface of the outer plate, thereby forming a sealed space inside.

  The outer plate may have the shape of the lid described above, and the outer lid may be the plate-shaped object described above. Further, the square or rectangular shape in a plan view on the outer plate or the outer lid may be changed to a circular or elliptical shape.

  The sealed space is a space that is independent from the outside of the mask storage container.For example, when the outer lid is fitted or brought into contact with the outer plate, foreign matter existing outside cannot enter the inside. That is. In order to form a sealed space, a sealing member may be installed at the position of the contact surface between the outer lid and the outer dish, either the outer lid or the outer dish.

  In the mask storage container, when the outer plate is combined with the outer lid, the inner lid and the inner plate that form a mask space for storing the pattern transfer mask inside the sealed space, and the mask storage that stores the pattern transfer mask And a check valve-equipped sealing port for introducing a gas having a cleanness lower than a predetermined cleanness into the mask space when the outer lid is removed from the outer plate of the container.

  The inner lid and the inner dish may have any shape as long as the outer lid and the outer dish are combined to form a mask space inside the sealed space. For example, the inner dish is an outer dish. It is possible to employ a square or rectangular plate-like object in plan view having an area smaller than the area of the pattern transfer mask and larger than the area of the pattern transfer mask to be accommodated. Further, for example, the inner lid has a square or rectangular shape in a plan view having an area smaller than the area of the outer lid and larger than the area of the pattern transfer mask to be accommodated, and has a cross-section in front view. A lid having a reverse concave shape can be employed. In order to form a mask space, the inner plate is supported above the outer plate, and when the outer lid is fitted to the outer plate, the inner lid is placed below the outer lid so that the inner plate covers the inner plate. The structure to support can be employ | adopted.

  Note that the inner dish has the shape of the lid described above, and the inner lid may be the plate-shaped object described above. Further, the square or rectangular shape in a plan view of the inner dish or the inner lid may be changed to a circular or elliptical shape.

  Further, since the pattern transfer mask is stored in the mask space, for example, an inner dish is provided with a mask holder for holding the pattern transfer mask.

  The sealing port with a check valve may be provided in any manner as long as it is a hole for introducing a gas having a cleanliness level lower than a predetermined cleanness into the mask space. The gas is introduced into the upper surface of the inner plate from below the outer plate, and the mask space is filled with the gas. The number of sealing ports may be one or more.

  The check valve attached to the filling port is configured to close the filling port when the gas is not introduced into the mask space and to open the filling port when the gas is introduced into the mask space. Since the check valve is in contact with the mask space, it is preferable that the check valve is made of a material that does not generate outgas.

  In addition, when the check valve shuts off the mask space and the space storing gas for introduction, the sealing port does not generate outgas so that no foreign matter is generated from the contact surface even if it comes into contact with the sealing port. It is preferable that it is comprised.

As the gas having a cleanliness lower than a predetermined cleanliness, for example, a high-purity nitrogen gas (Pure N ₂ ) having 1 μm or less of 0.1 μm foreign matter and a dew point of −110 ° C. or less is employed. You can, but you are not limited to this. The degree of cleanliness is defined in JIS Z 8122 (contamination control terminology) as an amount indicating the clean state of an object, and the size of a control target substance (contaminant) contained in a certain area or volume. It is a value indicated by the number and mass. The unit is the number of foreign substances per unit volume / cf, and cf is an abbreviation for Cubic Feet.

  The mask storage container has a predetermined gap that communicates the mask space and the sealed space between the inner lid and the inner dish when the outer lid and the outer dish are combined, and is used for pattern transfer. Either one of the inner lid and the inner dish is moved relative to the other along with the opening until a predetermined time has elapsed since the opening of the outer lid of the mask storage container storing the mask. Alternatively, the gap can be maintained.

  Although the said structure may be what kind of structure, the following structures are employable, for example.

  When the inner lid, which is a square plate in plan view, is combined with the inner lid, which has a square shape in plan view and whose cross section is a reverse concave shape, the peripheral edge of the inner dish and the inner side surface of the inner lid The inner plate holding the pattern transfer mask is inserted into the inner lid when the outer lid and the outer plate are put together. Then, when the outer tray is lowered from the outer lid at a predetermined lowering speed and the mask storage container is opened, the inner tray is moved with respect to the inner lid as the outer lid of the mask storage container storing the pattern transfer mask is opened. Even if the lowering is performed relatively, the inner lid and the inner cover are kept from the start of the opening of the outer lid until a predetermined time corresponding to the predetermined lowering speed and the amount of the inner lid entered into the inner lid has elapsed. A predetermined gap between the plates is maintained. In this configuration, the mask lid may be opened by raising the outer lid from the outer plate at a predetermined rising speed, and the inner lid may be raised relative to the inner plate as the outer lid is opened. The predetermined gap is maintained from the start of the opening of the outer lid until a predetermined time corresponding to the predetermined rising speed and the amount of approach elapses.

  This configuration is an example, and the inner dish may have a square shape in a plan view, and a cross section in a front view may have a reverse concave shape, and the inner lid may have a square plate shape in a plan view.

  Note that the time when the opening of the outer lid starts from the outer plate of the mask storage container is the time when a gap is generated between the lower surface of the peripheral edge of the outer lid and the upper surface of the outer plate.

  The predetermined gap may be any size, but the gas in the mask space flows out to the sealed space at a flow rate smaller than the flow rate of the gas introduced from the sealing port with a check valve into the mask space. Is preferred. For example, in order to suppress the outflow amount of gas to the sealed space, the thickness is 1 mm or less, preferably 100 μm or less.

  In addition, when the inner lid and the inner dish form a mask space with a predetermined gap, it is preferable that the inner lid and the inner dish are in a substantially non-contact state. The substantially non-contact state is a state where the inner lid and the inner dish are not in contact with each other or even when the inner lid and the inner dish are in contact with each other, no foreign matter is generated from the contact surface. For example, even if a part of the inner lid and part of the inner dish are in contact with each other and have a predetermined gap, no foreign matter is generated from the contact surface even if the inner lid and the inner dish form a mask space. The state is a substantially non-contact state. Furthermore, when the outer lid that supports the inner lid and the outer tray that supports the inner dish are combined, it is preferable that the inner lid is in a substantially non-contact state with respect to the inner dish and the outer dish.

  The inner lid and the inner dish described above are made of a material that generates less outgas, and for example, quartz (SiC) is used as the material.

  On the other hand, the bottom plate and the upper lid are made of engineering plastic, general-purpose plastic, and the like. Examples of the plastic include polyetheretherketone (PEEK), polycarbonate (PC), polybutylene terephthalate (PBT), and Teflon (registered trademark). ) (PFA), polypropylene (PP) and the like are used.

  The mask storage container of the present invention is also effective as an opening method.

  That is, in the opening method, when the outer plate, the outer lid that is combined with the outer plate so as to form a sealed space inside, and the outer lid and the outer plate are combined, the pattern transfer is performed inside the sealed space. A mask storage container including an inner lid and an inner dish that form a mask space for storing a mask, and a sealing valve-equipped inlet for introducing gas into the mask space is employed.

  In this opening method, in a state where the outer plate of the mask storage container storing the mask for pattern transfer and the outer lid are combined, the degree of cleanliness higher than a predetermined cleanliness is obtained from the sealing port with the check valve to the mask space. A first step of introducing the gas having the above and a second step of removing the outer lid from the outer plate of the mask storage container while introducing the gas into the mask space can be configured.

  The mask storage container is a mask storage container having a predetermined gap that communicates the mask space and the sealed space between the inner lid and the inner dish when the outer lid and the outer dish are combined. Can be adopted.

  Furthermore, the second step starts the opening of the outer lid while introducing gas into the mask space, and maintains the gap until a predetermined time elapses with the opening of the outer lid; And a step of removing the inner lid from the inner dish while introducing gas into the mask space after a predetermined time has elapsed.

  In the step of maintaining the gap until a predetermined time elapses with the opening of the outer lid, even if one of the inner lid and the inner dish is moved relative to the other, The inner plate may be stopped.

  The introduction amount of the gas introduced into the mask space may be the same in each step, or a different introduction amount may be set for each step, but the introduction amount is configured to increase as the step proceeds. Is preferred.

  The mask storage container of the present invention is preferably used as a container for storing a pellicleless reticle used for EUVL.

  According to the mask storage container of the present invention, when the outer lid and the outer plate are combined, the inner lid and the inner plate that form a mask space for storing the pattern transfer mask inside the sealed space, and the pattern transfer When the outer lid is removed from the outer plate of the mask storage container storing the mask, a sealing valve-equipped inlet for introducing a gas having a cleanliness lower than a predetermined cleanness into the mask space is provided.

  As a result, when the pattern transfer mask is stored in the mask storage container, it is stored in the mask space formed inside the sealed space, and thus is generated from the contact surface between the outer lid and the outer plate. It becomes possible to appropriately protect the pattern transfer mask from foreign matters. Further, since the sealing port with a check valve is provided, when the outer lid is removed from the outer plate of the mask storage container storing the pattern transfer mask, the gas having a cleanness lower than a predetermined cleanness is contained in the mask space. Will be introduced. Therefore, even if the pressure in the mask space is temporarily higher than the atmospheric pressure and the volume of the mask space expands with the opening of the mask storage container, the pressure in the negative pressure state in which the atmospheric pressure in the mask space is temporarily lower than the atmospheric pressure. Occurrence can be prevented. As a result, it is possible to keep the cleanness of the mask space at a low level without causing foreign matter generated from the contact surface between the outer lid and the outer pan to enter the mask space. As a result, it is possible to improve the quality and yield of semiconductor manufacturing.

  Further, when the outer lid and the outer dish are combined, the mask having a predetermined gap that communicates the mask space and the sealed space between the inner lid and the inner dish and storing the pattern transfer mask Even if one of the inner lid and the inner dish is moved relative to the other as the outer lid of the storage container is opened, the gap is maintained until a predetermined time elapses. Can do.

  As a result, when the outer lid is removed from the outer plate of the mask storage container containing the pattern transfer mask, the gas filled in the mask space at a pressure higher than the atmospheric pressure flows out to the sealed space through a predetermined gap. Since the predetermined gap is maintained until a predetermined time elapses, the flow rate of the outflowing gas becomes a predetermined flow rate. Therefore, until a predetermined time elapses, the gas in the mask space is prevented from abruptly flowing out into the sealed space, and the pressure in the mask space is prevented from rapidly converging to the atmospheric pressure. It becomes possible to keep the atmospheric pressure in the mask space higher than the atmospheric pressure. As a result, it is possible to eliminate as much as possible the possibility that foreign matter generated from the contact surface between the outer lid and the outer dish enters the mask space, and to keep the cleanliness of the mask space low.

  In addition, the same operation effect is produced also in the opening method of the mask storage container of the present invention.

  Further, the inner lid and the inner dish can be made of a material that generates less outgas.

  As a result, the material that forms the mask space is made of a material that generates less outgas. Therefore, the possibility of foreign matter entering the mask space is eliminated as much as possible, and the cleanliness of the mask space is reduced to a low level. It becomes possible to keep.

  Hereinafter, a mask storage container and a method for opening the same according to the present invention will be described with reference to the drawings. In addition, although the mask storage container shown below demonstrates using a reticle as a mask for pattern transfer, it is not restricted to this. As the reticle, a pellicleless reticle for EUVL is employed. FIG. 1 is a front sectional view showing the structure of a mask storage container according to the present invention. In the following description, the vertical direction in FIG. 1 is the vertical direction of the mask storage container, and the horizontal direction in FIG. 1 is the horizontal direction of the mask storage container.

  As shown in FIG. 1A, a mask storage container 100 is a pattern transfer mask that includes an outer plate 101 and an outer lid 103 that is in close contact with the upper surface of the outer plate 101 and forms a sealed space 100a therein. The reticle 107 is stored.

  The outer plate 101 is formed as a square plate-like object in plan view, and is configured to have an area larger than the area of the pattern surface of the reticle 107. The outer lid 103 has a square shape having an area larger than the area of the pattern surface of the reticle 107 in plan view, and is configured as a lid having a reverse concave shape in front view. When the outer lid 103 is combined with the outer plate 101, the entire lower surface of the peripheral portion 103a of the outer lid 103 is in contact with the upper surface of the outer plate 101, and a sealed space 100a having no gap between both surfaces is formed inside the mask storage container 100. The The sealed space 100 a is blocked from the outside of the mask storage container 100 with the outer lid 103 and the outer dish 101 as a boundary (wall). In addition, that all the lower surfaces of the peripheral edge portion 103a of the outer lid 103 are in contact with the outer pan 101 means that no gap is generated between both surfaces.

  The outer plate 101 is provided with an inner plate support 105 that floats the inner plate 102 in a hollow state and supports the inner plate 102 in a substantially horizontal state. The inner dish 102 is formed as a square plate-like object in plan view, and has an area larger than the area of the pattern surface of the reticle 107 and an area smaller than the area of the outer dish 101.

  Further, the inner plate 102 is provided with a reticle holder 110 that floats the reticle 107 in a hollow state and holds the reticle 107 in a substantially horizontal state. Four reticle holders 110 are provided on the upper surface of the inner plate 102 so as to hold the four corners of the reticle. When the reticle 107 is held by the reticle holder 110, the reticle holder 110 is held by the reticle holder 110 with the glass surface 108 facing upward and the pattern surface 109 on which the pattern is formed facing downward. .

  In addition, when the outer plate 101 is put on the outer lid 103, the inner lid 104 that covers the inner plate 102 and forms the mask space 100 b that houses the reticle 107 inside the sealed space 100 a is provided inside the outer lid 103. Is provided.

  FIG. 1B shows the relationship between the sealed space 100a and the mask space 100b in a front sectional view of the mask storage container. As shown in FIG. 1B, it is understood that the mask space 100b is formed in the sealed space 100a, and the stored reticle 107 is stored in the two-layer structure including the sealed space 100a and the mask space 100b. The

  Further, as shown in FIG. 1A, the inner lid 104 has a square shape having an area larger than the area of the inner dish 102 in a plan view, and is configured as a lid having a reverse concave shape in a front view. The inner lid 104 is supported in a hollow state by an inner lid support 106 provided on the outer lid 103, and the inner lid 104 is supported by being nested with respect to the outer lid 103.

  The peripheral edge portion 104 a of the inner lid 104 supported by the outer lid 103 has a configuration that extends toward the upper surface of the outer pan 101 in a state where the outer pan 101 is aligned with the outer lid 103. A predetermined gap (hereinafter referred to as a first gap G1) is formed between the extended lower surface of the peripheral edge 104a and the upper surface of the outer plate 101. In this configuration, the lower surface of the peripheral edge portion 104 a of the inner lid 104 and the upper surface of the outer plate 101 do not contact each other.

  In addition, the inner lid 104 covers the inner plate 102 and the mask space 100b is formed in a state where the outer plate 101 is aligned with the outer lid 103. The shape of the inner plate 102 is the inner plate 102 that matches the inner lid 104. A predetermined gap (hereinafter referred to as a second gap G2) is formed between the peripheral edge portion 102a and the inner side surface 104b of the inner lid 104. By having the second gap G2, the inner lid 104 and the inner dish 102 are not in contact with each other and the mask space 100b is formed, so that the generation of foreign matters due to the contact between the inner lid 104 and the inner dish 102 is prevented. It becomes possible to do.

  Furthermore, when the outer plate 101 is fitted to the outer lid 103, the inner plate 102 is moved from the lower surface of the peripheral edge 104 a of the inner lid 104 by a predetermined amount while maintaining the second gap G 2. Configured to enter the interior. In other words, the configuration is such that when the outer plate 101 is aligned with the outer lid 103, the inner plate support body 105 positions the inner plate 102 higher than the lower surface of the peripheral portion 104 a of the inner lid 104 from the upper surface of the outer plate 101. It corresponds to the configuration supported in. The amount of entry is the distance between the lower surface of the peripheral edge 104 a of the inner lid 104 and the upper surface of the inner dish 102. When the inner plate 102 is lowered relative to the inner lid 104 with the outer lid 101 being aligned with the outer lid 103, the second gap G2 is widened and the mask space is opened.

  The relationship between the outer plate 101, the inner plate 102, the inner lid 104, and the inner plate support 105 described above is shown in FIG.

  As shown in FIG. 2, the height H <b> 1 of the inner dish support 105, that is, the distance between the upper surface of the outer dish 101 and the lower surface of the inner dish 102, is the peripheral edge 104 a of the upper surface of the outer dish 101 and the inner lid 104. From the value obtained by adding the first gap G1 between the lower surface of the inner lid 104 and the predetermined amount H2 between the lower surface of the peripheral edge 104a of the inner lid 104 and the upper surface of the inner plate 102, the vertical direction of the inner plate 102 Is a value obtained by dividing the predetermined thickness T.

  With this structure, for example, when the outer plate 101 is lowered from the outer lid 103 at a predetermined lowering speed and the mask storage container 100 is opened, the predetermined entry amount H2 is decreased by a predetermined amount after the opening of the outer lid 103 is started. The second gap G2 formed between the inner lid 104 and the inner dish 102 is maintained until a predetermined time divided by the speed has elapsed. Note that, for a predetermined time, the lowering speed of the outer plate 101 is adjusted, the predetermined entry amount H2 is adjusted, the predetermined thickness T in the vertical direction of the inner plate 102 is adjusted, the inner plate support 105 is The height H1 can be adjusted as appropriate by adjusting the height H1.

  Further, as shown in FIG. 1A, the outer surface of the outer lid 103 is extended so as to protrude from a predetermined position, and is bent downward from a position corresponding to the upper part of the peripheral edge of the outer plate 101. When the outer plate 101 is fitted to the outer lid 103, the peripheral portion 103b extends to a depth that completely covers the periphery of the outer plate 101 with a predetermined gap from the peripheral edge of the outer plate 101. Is provided. When opening the outer lid 103, through a gap formed between the lower surface of the peripheral edge portion 103a of the outer lid 103 and the upper surface of the outer plate 101 (hereinafter referred to as a third gap G3, which will be described later) When the gas flows out from the sealed space 100a to the outside, the surrounding portion 103b guides the outflowing gas to the lower side of the outer plate 101 so that foreign substances existing around the mask storage container 100 are not scattered in the air. .

  The outer plate 101, the outer lid 103, the inner plate support 105, and the inner cover support 106 are formed of polyether ether ketone (PEEK), and the inner plate 102 and the inner cover 104 are formed of quartz (SiC). The

  Further, as shown in FIG. 1A, the mask storage container 100 has a gas having a cleanliness level lower than a predetermined cleanliness when the outer lid 103 is removed from the outer plate 101 of the mask storage container 100 storing the reticle 107. An inlet 111 with a check valve is provided for introducing the gas into the mask space.

  The check valve-equipped sealing port 111 penetrates the outer plate 101 and the inner plate 103, introduces gas from below the outer plate 101 to the upper surface of the inner plate 103, and fills the mask space with gas. The A check valve (not shown) attached to the sealing port 111 is configured to close the sealing port 111 when gas is not introduced into the mask space 100b. Further, when the gas is introduced into the mask space 100b, the check valve is configured to open the sealing port 111. The check valve prevents the gas filled in the mask space from flowing back through the sealing port 111.

  The opening / closing of the check valve is controlled by, for example, the pressure of the introduced gas. When the gas is not introduced, the sealing port 111 is closed by the self-weight of the check valve. When the gas is introduced, the check valve is lifted by the pressure of the gas and the sealing port 111 is opened. In addition, the said gas is supplied to the sealing port 111 with a non-return valve by the gas supply means which is not shown in figure. The gas supply means is configured to continuously introduce gas into the mask space 100b from the sealing port with check valve 111 into the mask space 100b when the mask storage container 100 is opened.

As the gas having a cleanliness lower than a predetermined cleanliness, for example, a high purity nitrogen gas (Pure N ₂ ) having 0.1 μm foreign matter / piece or less and a dew point of −110 ° C. or less is employed. The

  When the outer lid 103 is opened, although not shown, the outer lid 103 is detachably supported at a predetermined position by a fixing means, and the outer plate 101 is fixed by an elevating means that moves up and down a predetermined distance. A range from a position where the outer cover 103 and the outer plate 101 are combined to a predetermined distance downward is supported so as to be movable up and down.

  When the reticle 107 is stored in the mask storage container 100, first, with the fixing means fixing the outer lid 103, the elevating means lowers the outer plate 101 in which the reticle 107 is not stored, and the mask storage container 100 Is released. Further, a conveying means (not shown) holds the reticle 107 on the reticle holder 110 of the inner plate 103 with the pattern surface of the reticle 107 downward and the glass surface upward. Next, the lifting / lowering means raises the outer plate 101, puts the outer lid 103 and the outer plate 101 together, and stores the reticle 107 in the mask storage container 100.

  On the other hand, when the reticle 107 is taken out from the mask storage container 100, the elevating means moves while the gas supply means introduces gas into the mask space from the sealing valve 111 with the check valve while the outer cover 103 is fixed by the fixing means. The outer plate 101 is lowered to open the mask storage container 100. Further, the conveying means takes out the reticle 107 from the reticle holder 110. Next, the raising / lowering means raises the outer plate 101, the outer lid 103 and the outer plate 101 are put together, and the mask storage container 100 is closed.

  Next, a procedure for opening the mask storage container 100 in which the reticle is stored will be described with reference to FIGS. FIG. 3 is a front sectional view of the mask storage container 100 of the present invention in a closed state. 3 will be described as the vertical direction of the mask storage container, and the horizontal direction of FIG. 3 will be described as the horizontal direction of the mask storage container. The broken line arrows in FIG. 3 indicate the flow of gas introduced from the sealing port 111.

  As described above, when the mask storage container 100 storing the reticle 107 is closed, a sealed space 100a is formed by the outer lid 103 and the outer plate 101, and a mask space 100b is formed by the inner lid 104 and the inner plate 102. Is formed. The sealed space 100a and the mask space 100b are communicated by a second gap G2 between the peripheral edge portion 102a of the inner dish 102 and the inner side surface 104b of the inner lid 104.

  In a state where the outer plate 101 of the mask storage container 100 storing the reticle 107 and the outer lid 103 are combined, the gas supply means introduces a predetermined amount of high-purity nitrogen gas from the sealing port 111 with a check valve into the mask space ( For example, it is introduced at a rate of 3.5 liters / minute (step 1).

  When the gas is introduced into the mask space 100 b from the sealing port 111 with the check valve, the gas flows to the vicinity of both ends of the reticle 107 along the lower part of the reticle 107 floating in the air above the inner lid 104. Further, the gas in the vicinity of both ends of the reticle 107 flows above the reticle 107 and reaches every corner of the mask space 100b. As a result, first, the gas fills the mask space 100b and raises the atmospheric pressure in the mask space 100b.

  When the atmospheric pressure in the mask space 100b rises, the mask space 100b becomes a positive pressure state, and the atmospheric pressure in the mask space becomes higher than that in the sealed space 100a. Therefore, the gas in the mask space 100b passes through the second gap G2. Then, it flows below the inner lid 104 and passes through the first gap G1 between the lower surface of the peripheral edge 104a of the inner lid 104 and the upper surface of the outer plate 103. The gas that has passed through the first gap G1 flows to the outside of the inner lid 104 and fills the sealed space 100a. When the sealed space 100a is filled with gas, the cross-sectional area of the gas formed by the second gap G2 communicating the sealed space 100a and the mask space 100b and the flow of the gas formed by the first gap G1 Since the road cross-sectional area is limited, the air pressure in the sealed space 100a rises more slowly than the air pressure in the mask space 100b that is directly supplied with gas from the sealing port with check valve 111, and the positive pressure It becomes a state. In addition, since all the lower surfaces of the peripheral edge portion 103a of the outer lid 103 of the mask storage container 100 and the upper surface of the outer plate 101 are in contact with each other, the gas does not leak from the sealed space to the outside.

  In addition, the introduction of gas from the sealing port 111 with a check valve into the mask space 100b is performed for a predetermined time (gas introduction) required for the mask space 100b and the sealed space 100a to be in a positive pressure state with respect to the outside. Although it is appropriately changed according to the amount, it is continuously executed (for example, about 2 seconds).

  Next, a state in which the mask storage container 100 storing the reticle 107 has started to open will be described. FIG. 4 is a cross-sectional view in front view of the state in which the mask storage container starts to open. 4 will be described as the vertical direction of the mask storage container, and the horizontal direction of FIG. 4 will be described as the horizontal direction of the mask storage container. The broken-line arrows in FIG. 4 indicate the flow of gas introduced from the sealing port 111.

  In a state where the gas is filled in the mask space 100b and the sealed space 100a, the gas supply means introduces high purity nitrogen gas into the mask space 100b in a predetermined introduction amount, while the elevating means is a mask storage container at a predetermined lowering speed. The outer plate 101 of 100 is lowered and the opening of the outer lid 103 is started (step 2).

  As described above, in the mask storage container 100 of the present invention, the outer plate 101, the inner plate 102, the inner plate support body 105, and the reticle holder 110 are integrally configured, and the outer cover 103, the inner cover 104, and the inner cover support body. 106 is formed as a single unit. Therefore, when the outer plate 101 is moved downward without moving left and right in a state where the outer plate 101 is fitted to the outer lid 103, all the lower surfaces of the peripheral edge portion 103a of the outer lid 103 and the upper surface of the outer plate 101 are detached. Therefore, the sealed space 100a communicates with the outside of the mask storage container 100 through the separated gap G3.

  Immediately after the communication, the pressure in the sealed space 100a is more positive than the atmospheric pressure, so even if the volume of the sealed space 100a expands, the sealed space 100a does not become a negative pressure and fills the sealed space 100a. The gas that has been discharged flows out through the gap G3. Since the gas flows out from the sealed space 100a to the outside, the foreign matter generated on the contact surface between the peripheral edge portion 103a of the outer lid 103 and the outer plate 101 also flows out to the outside, so that the foreign matter enters the sealed space 100a. There is nothing. Note that the first gap G1 expands as the elevating means further lowers the outer plate 101 from the outer lid 103, and promotes the outflow of gas from the sealed space 100a to the outside. Accordingly, the gas pressure in the sealed space 100a rapidly decreases due to the outflow of gas from the sealed space 100a to the outside. The state in which the pressure in the sealed space 100a is rapidly reduced corresponds to a state in which the sealed space 100a is opened or a state in which the outer lid 103 is removed from the outer plate 101. Note that the gas flowing out from the sealed space 100 a is guided and flows out below the outer plate 101 by the peripheral portion 103 b provided in the outer lid 103.

  On the other hand, the mask space 100b also communicates with the outside of the mask storage container 100 through the sealed space 100a, and the volume of the mask space 100b expands. However, due to the configuration of the mask storage container 100, the outer lid 103 is opened. Even if the inner plate 102 descends with respect to the inner lid 103 with the opening until a predetermined time (for example, about 3 seconds) elapses from the start of the operation, the peripheral portion 102a of the inner plate 102 and the inner portion The second gap G2 between the inner surface 103b of the lid 103 remains maintained. Therefore, as long as the second gap G2 is kept wide, the flow rate of the gas passing through the second gap G2 is also constant, and the flow rate of the gas flowing out from the mask space 100b to the sealed space 100a is limited. .

  Further, while the outer plate 101 of the mask storage container 100 is lowered, gas is continuously introduced into the mask space 100b from the sealing port 111 with a check valve. Since the amount of gas introduced into the mask space 100b is larger than the amount of gas flowing out from the mask space 100b through the second gap G2, the atmospheric pressure in the mask space 100b decreases. It will rise gently. That is, by maintaining the second gap G2, the mask space 100b maintains a positive pressure state. As long as the mask space 100b is in a positive pressure state, the state corresponds to a state where the mask space 100b is not opened or a state where the inner lid 104 is not removed from the inner dish 102. As described above, the predetermined time during which the second gap G2 is maintained is determined by the approach amount H2 between the lower surface of the peripheral edge portion 104a of the inner lid 104 and the upper surface of the inner dish 102 and a predetermined lowering speed. Is done.

  Since the gas outflow amount described above increases in proportion to the air pressure in the mask space 100b, the gas outflow amount increases as the air pressure in the mask space 100b increases. Therefore, when the pressure in the mask space 100b reaches a predetermined value, the amount of gas introduced and the amount of gas outflow are balanced, and the pressure in the mask space 100b does not increase.

  Further, as shown by the broken line arrow in FIG. 4, the gas introduced into the mask space 100b is connected to the second space when the sealed space 100a communicates with the outside of the mask storage container 100 via the third gap G3. It becomes easy to flow out into the sealed space 100a through the gap G2, and the gas flowing out into the sealed space 100a is likely to flow out to the outside rather than staying in the sealed space 100a.

  Next, a state in which the mask storage container 100 storing the reticle 107 is opened will be described. FIG. 5 is a front sectional view of the mask storage container 100 according to the present invention in an opened state. Note that the vertical direction in FIG. 5 is the vertical direction of the mask storage container, and the horizontal direction in FIG. 5 is the horizontal direction of the mask storage container. The broken line arrows in FIG. 5 indicate the flow of gas introduced from the sealing port 111.

  When a predetermined time elapses after the opening of the outer lid 103 is started, the gas supply means introduces a high purity nitrogen gas into the mask space 100b with a predetermined introduction amount, and the elevating means moves the mask storage container at a predetermined lowering speed. The 100 outer plates 101 are lowered to remove the inner plate 102 from the inner lid 104 (step 3).

  As the outer plate 101 further descends, the first gap G1 and the third gap G3 further expand, and the inner plate 102 moves out of the inner lid 104 and is maintained until now. The gap G2 is widened. Therefore, the outflow amount of gas from the mask space 100b becomes larger than the introduction amount of gas from the check valve-equipped sealing port 111, and the pressure in the mask space 100b rapidly decreases. The state in which the pressure in the mask space 100b is rapidly reduced corresponds to the state in which the mask space 100b is opened or the state in which the inner lid 104 is removed from the inner dish 102. Similarly, the air pressure in the sealed space 100a also decreases. After a while with the mask storage container 100 opened, the pressure in the mask space 100b and the pressure in the sealed space 100a approach the atmospheric pressure and become equal.

  Note that, as indicated by the broken line arrows in FIG. 5, the first gap G1 and the second gap G2 are widened, so that the gas introduced into the mask space 100b is difficult to flow above the reticle 107, and the sealed space 100a. To flow directly into. Further, the gas flowing in the sealed space 100a also becomes difficult to stay inside the outer lid 103 due to the third gap G3 spreading, and flows directly to the outside.

  When the outer plate 101 is lowered to a predetermined position by the elevating means, the opening of the mask storage container 100 is completed. In steps 2 and 3, the mask storage container 100 is opened through a two-stage opening of the internal space including the opening of the sealed space and the opening of the mask space.

  Next, changes over time in the atmospheric pressure in the mask space 100b and the atmospheric pressure in the sealed space 100a in the state shown in FIGS. 3 to 5 will be described with reference to FIG. FIG. 6 shows changes over time in the atmospheric pressure of the mask space 100b, the atmospheric pressure of the sealed space 100a, and the atmospheric pressure when the mask storage container 100 storing the reticle 107 is opened. The time t1 in FIG. 6 is the time when the outer plate 101 starts to descend with respect to the outer lid 103 (the time when the opening of the outer lid 103 starts from the outer plate 101 or the time when the sealed space 100a is opened), and the time t2 is When the second gap G2 is widened and the inner lid 104 is removed from the inner plate 102 (when the mask space 100b is opened), the time t3 is the time when the descent of the outer plate 101 is completed and a predetermined time has elapsed ( At the time when the opening of the mask storage container 100 is completed), the atmospheric pressure P1 indicates the value of atmospheric pressure.

  The method for measuring the atmospheric pressure in the mask space 100b is to install a commercially available electric barometer at a predetermined position in the mask space 100b (for example, a part of the inner wall of the inner lid 104), and to adjust the atmospheric pressure in the mask space 100b. Was measured. The method for measuring the air pressure in the sealed space 100a is the same. However, when the air pressure in the sealed space 100a is measured, an electric type is applied to a predetermined position of the sealed space 100a (for example, a part of the inner wall of the outer lid 103). A barometer was installed to measure the pressure in the sealed space 100a.

  As shown in FIG. 6, in a state where the mask storage container 100 is closed, a period from the time when the high purity nitrogen gas starts to be introduced into the mask space 100b from the sealing port with check valve 111 to the time t1 (for example, 2 seconds, hereinafter referred to as period T1), since the entire lower surface of the peripheral edge portion 103a of the outer lid 103 and the upper surface of the outer plate 101 are in contact with each other, the pressure in the mask space 100b and the pressure in the sealed space 100a are Both rise. In the mask space 100b, gas is directly introduced from the sealing port with check valve 111, whereas in the sealed space 100a, gas is introduced only from the second gap G2, so the rate of increase in the atmospheric pressure of the mask space 100b is It becomes higher compared with the rate of increase in the atmospheric pressure of the sealed space 100a. In FIG. 6, it is understood that the slope of the straight line of the atmospheric pressure in the mask space 100b is higher than the slope of the straight line of the atmospheric pressure in the sealed space 100a in the period T1.

  Next, in the period from the time point t1 to the time point t2 (for example, 3 seconds, hereinafter referred to as period T2), the outer plate 101 of the mask storage container 100 starts to descend, so the outer lid 103 All the lower surfaces of the peripheral edge portion 103a and the upper surface of the outer plate 101 are detached, and the sealed space 100a communicates with the outside through the third gap G3. Therefore, in FIG. 6, it is understood that the pressure curve of the sealed space 100a decreases rapidly and converges to the atmospheric pressure P1.

  On the other hand, when the sealed space 100a communicates with the outside, the mask space 100b communicates with the sealed space 100a via the second gap G2 in advance, so that the mask space 100b communicates with the outside. As described above, high-purity nitrogen gas is continuously introduced into the mask space 100b with a predetermined introduction amount through the sealing port 111, and gas flows out into the sealed space 100a with a predetermined outflow amount by the maintained second gap G2. . Since the gas introduction amount is larger than the gas outflow amount, the atmospheric pressure curve in the mask space 100b rises gently in the period T2, as shown in FIG. Further, the pressure value of the mask space 100b converges to a predetermined value P2 at the time when the gas outflow amount and the gas introduction amount are balanced. Further, the rate of increase in atmospheric pressure (straight line) in the mask space 100b during the period T2 is the first stage, that is, the rate of increase in atmospheric pressure (line slope) in the mask space 100b during the period T1 due to outflow of gas. ) Is a lower value. As shown in FIG. 6, although the pressure difference between the atmospheric pressure P1 and the predetermined value P2 varies depending on the volume of the mask storage container 100, the amount of gas introduced, and the width of the second gap G2, the time t2 At that time, it became 0.5 MPa.

  Furthermore, in the period from time t2 to time t3 (for example, 7 seconds, hereinafter referred to as period T3), the second gap G2 that connects the sealed space 100a and the mask space 100b is widened. The atmospheric pressure in the mask space 100b that has converged to the predetermined value P2 rapidly decreases and approaches the atmospheric pressure P1. Further, the air pressure in the sealed space 100a further approaches the atmospheric pressure P1 as the third gap G3 further expands. Finally, the atmospheric pressure in the mask space 100b and the atmospheric pressure in the sealed space 100a converge to the atmospheric pressure P1 for a while.

  Thus, in the opening procedure of the mask storage container 100 having the above-described configuration, the atmospheric pressure of the mask space 100b always has a value higher than the atmospheric pressure of the sealed space 100a, and the atmospheric pressure of the sealed space 100a is the atmospheric pressure P1. Will have a higher value. That is, since the mask space 100b in which the reticle 107 is stored is always in a positive pressure state with respect to the sealed space 100a or the outside when the mask storage container 100 is opened, it is ensured that foreign matter enters from the sealed space 100a or the outside. It becomes possible to prevent. Moreover, since the sealed space 100a is also in a positive pressure state with respect to the outside when the mask storage container 100 is opened, the foreign matter generated from the contact surface between the outer plate 101 and the outer lid 103, which has been a concern in the past, can be reliably ensured. It is possible to flow out to the outside. As a result, the mask space 100 can always maintain a low cleanness value.

  Now, it will be described based on the experimental results of FIG. 7 that the mask space 100 always maintains a low cleanness value. FIG. 7 is a graph showing the relationship between the number of opening / closing operations when the mask storage space is opened and the number of foreign matters in the mask storage container in the mask storage container of the present invention and the conventional mask storage container. The conventional mask storage container corresponds to the mask storage container 810 shown in FIG. 8, and does not introduce a gas having a cleanliness lower than a predetermined cleanness into the internal space 810a.

  As a method for measuring the number of foreign substances in the mask storage container, an air particle counter is installed in the mask space of the mask storage container, and the air is released every predetermined number of times (for example, every 500 times). The number of medium particles was measured. In the mask storage container 100 of the present invention, the air particle counter is installed, for example, on the inner side wall of the inner lid 104 in the mask space 100b. On the other hand, in the conventional mask storage container 810, the air particle counter is installed, for example, on the inner wall of the upper lid 816 in the internal space 810a. A commercially available air particle counter was used, and the particle size (particle size classification) to be detected by the air particle counter was set to 0.3 μm or more, and the measurement time was set to 60 seconds. The unit of the number of particles in the air is the number / cf indicating the number of foreign matters per unit volume.

  As shown in FIG. 7, in the conventional mask storage container 810, it is understood that the number of air particles in the internal space 810a starts to increase after the number of opening and closing exceeds 2000 times. Further, it is understood that when the number of times of opening and closing the conventional mask storage container 810 increases, the number of air particles increases with the increase. In the conventional mask storage container 810, foreign substances start to be generated from the contact surface between the bottom plate 811 and the upper lid 816 after the number of opening and closing starts to exceed 2000 times, and the internal space 810a is exposed to negative pressure when opened. This indicates that the generated foreign matter easily entered the internal space 810a and increased the number of particles in the air. Note that the number of particles in the air increases with the increase in the number of times the conventional mask container 810 is opened and closed because the wear on the contact surface between the bottom plate 811 and the upper lid 816 becomes significant due to the increase in the number of times of opening and closing. This is because the amount of generation increases.

  On the other hand, in the mask storage container 100 of the present invention, no increase in the number of airborne particles was observed even when the number of times of opening and closing exceeded 10,000. As described above, in the mask storage container 100 of the present invention, since the mask space 100b is always in a positive pressure state when opened, foreign matter does not enter from the outside, so the number of air particles does not increase. It is shown that.

  As described above, in the above-described mask storage container, when the outer lid and the outer plate are combined, the inner lid and the inner plate that form a mask space for storing the reticle in the sealed space, and the mask storing the reticle When the outer lid is removed from the outer plate of the storage container, a sealing valve-equipped inlet for introducing a gas having a cleanliness lower than a predetermined cleanliness into the mask space is provided.

  As a result, when the reticle is stored in the mask storage container, it is stored in the mask space formed inside the sealed space, so that the reticle is removed from the foreign matter generated from the contact surface between the outer lid and the outer plate. Can be properly protected. Further, since the sealing port with a check valve is provided, when the outer lid is removed from the outer plate of the mask storage container storing the reticle, a gas having a cleanness lower than a predetermined cleanness is introduced into the mask space. Will be. Therefore, even if the pressure in the mask space is temporarily higher than the atmospheric pressure and the volume of the mask space expands with the opening of the mask storage container, the pressure in the negative pressure state in which the atmospheric pressure in the mask space is temporarily lower than the atmospheric pressure. Occurrence can be prevented. As a result, it is possible to keep the cleanness of the mask space at a low level without causing foreign matter generated from the contact surface between the outer lid and the outer pan to enter the mask space, and contamination of the reticle pattern surface by foreign matter can be prevented. It is possible to improve the quality and yield of semiconductor manufacturing.

  Further, when the outer lid and the outer dish are combined, the mask having a predetermined gap that communicates the mask space and the sealed space between the inner lid and the inner dish and storing the pattern transfer mask As the outer lid of the storage container is opened, the gap is maintained until a predetermined time elapses even if either the inner lid or the inner dish is moved relative to the other. be able to.

  As a result, when the outer lid is removed from the outer plate of the mask storage container containing the reticle, the gas filled in the mask space at a pressure higher than the atmospheric pressure passes through the predetermined gap and flows out into the sealed space. Since the predetermined gap is maintained until the time elapses, the flow rate of the outflowing gas becomes the predetermined flow rate. Therefore, until a predetermined time elapses, the gas in the mask space is prevented from abruptly flowing out into the sealed space, and the pressure in the mask space is prevented from rapidly converging to the atmospheric pressure. It becomes possible to keep the atmospheric pressure in the mask space higher than the atmospheric pressure. As a result, it is possible to eliminate as much as possible the possibility that foreign matter generated from the contact surface between the outer lid and the outer dish enters the mask space, and to keep the cleanliness of the mask space low.

  Further, the inner lid and the inner dish can be made of a material that generates less outgas.

  As a result, the material that forms the mask space is made of a material that generates less outgas. Therefore, the possibility of foreign matter entering the mask space is eliminated as much as possible, and the cleanliness of the mask space is reduced to a low level. It becomes possible to keep.

  In addition, the same operation effect is produced also in the opening method of the mask storage container of the present invention.

  Further, in the embodiment of the present invention, the outer lid is supported so as to be detachable and the outer plate can be raised and lowered. However, the outer lid may be raised and lowered and the outer plate may be removable. Absent.

  As described above, the mask storage container according to the present invention is useful for storing a pattern transfer mask for EUVL (a member for manufacturing a semiconductor device such as a photomask) that needs to maintain the inside of the container with low cleanliness. It is effective as a mask storage container that can store a pattern transfer mask while keeping the value of the internal cleanliness at a very low value.

It is sectional drawing of the front view which shows the structure of the mask storage container which concerns on this invention. It is an enlarged view of the cross section of the front view which shows the structure of the mask storage container which concerns on this invention. It is sectional drawing of the front view of the state in which the mask storage container concerning this invention was closed. It is sectional drawing of the front view of the state which the mask storage container concerning this invention started to open. It is sectional drawing of the front view of the state by which the mask storage container based on this invention was open | released. It is the figure which showed the time-dependent change of the atmospheric pressure of mask space, the atmospheric pressure of sealed space, and atmospheric pressure when the mask storage container which concerns on this invention is open | released. 6 is a graph showing the relationship between the number of times of opening and closing when the mask storage space is opened and the number of foreign matters in the mask storage container in the mask storage container of the present invention and the conventional mask storage container. It is sectional drawing of the front view which shows the structure of the storage conveyance case of the conventional member for semiconductor device manufacture.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Mask storage container 100a Sealed space 100b Mask space 101 Outer plate 102 Inner plate 103 Outer lid 104 Inner lid 105 Inner plate support body 106 Inner lid support body 107 Reticle 108 Glass surface 109 Pattern surface 110 Reticle holding body 111 Sealing with check valve Entrance 810 Storage and transport case 810a Internal space 811 Bottom plate 812 Reticle 813 Reticle holder 814 Glass surface 815 Pellicle surface 816 Top lid

Claims (4)

In a mask storage container that includes an outer plate and an outer lid that fits with the outer plate so as to form a sealed space therein, and stores a pattern transfer mask in the sealed space,
An inner lid and an inner dish that form a mask space for storing a pattern transfer mask inside the sealed space when the outer lid and the outer dish are combined;
A sealing valve with a check valve for introducing a gas having a cleanliness lower than a predetermined cleanliness into the mask space when the outer lid is removed from the outer plate of the mask storage container storing the mask for pattern transfer. A mask storage container comprising the mask storage container. When the outer lid and the outer dish are combined, a predetermined gap that communicates the mask space and the sealed space is provided between the inner lid and the inner dish,
Either one of the inner lid and the inner dish is relatively moved with respect to the other until the predetermined time elapses after the opening of the outer lid of the mask storage container containing the pattern transfer mask is started. The mask container according to claim 1, wherein the gap is maintained even when the mask is moved.   The mask storage container according to claim 1, wherein the inner lid and the inner dish are made of a material that generates less outgas. A mask space for storing a pattern transfer mask in the sealed space when the outer lid, the outer lid that fits the outer dish so as to form a sealed space inside, and the outer lid and the outer dish are combined. An opening method of a mask storage container comprising an inner lid and an inner plate to be formed, and a sealing port with a check valve for introducing gas into the mask space,
First, a gas having a cleanliness higher than a predetermined cleanness is introduced into the mask space from the sealing port with a check valve in a state where the outer plate and the outer lid of the mask storage container storing the mask for pattern transfer are combined. And the steps
And a second step of removing the outer lid from the outer plate of the mask container while introducing gas into the mask space.

Images