JP2005274724A - Storage container for photomask blank and its supporting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a storage container for a photomask blank and its supporting method by which the photomask blank can be conveyed while generation of a particle causing a defect is prevented as much as possible, the highly accurate photomask blank hardly having the defect can be provided, thereby a photomask having a finer pattern can be highly accurately formed and fine pattern exposure is made possible. <P>SOLUTION: In the storage container for the photomask blank provided with a container main body and a lid body for storing the photomask blank in its interior, wherein a supporting member made of synthetic resin and a spring member made of synthetic resin are respectively provided on the inner surfaces of a pair of facing wall parts of the container and one mutually facing both side surfaces of the photomask blank are supported by the both members by using elastic force generated by pressurization of these members to the photomask blank to store the photomask blank, the elastic force of the the spring member is so set that pressurizing force given to the both side surfaces of the photomask blank by the supporting member and the spring member is 1.96 to 117.6 N. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photomask blank storage container and support method used for manufacturing semiconductor integrated circuits and the like, and more particularly to a photomask blank storage container and support method in which the generation of particles affecting the occurrence of defects is reduced.

  Photomasks used in a wide range of applications, including the manufacture of semiconductor integrated circuits such as IC and LSI, basically have a light-shielding film mainly composed of chromium, molybdenum silicon, etc. on a translucent substrate. It is formed in a predetermined pattern. In recent years, pattern miniaturization has rapidly progressed with market demands such as higher integration of semiconductor integrated circuits. With the miniaturization of this pattern, it is required to provide a photomask blank without a minute defect.

  Up to now, the photomask blank manufacturing process, for example, the process of forming a film on a quartz substrate, the cleaning process after the film formation, the particles that give minute defects generated in the resist coating process, etc. are reduced. Various methods have been proposed, and a technique capable of manufacturing a photomask with extremely few defects has been established.

  However, even if the photomask blank is manufactured with such a method and is strictly controlled, when the photomask blank is used for the next photomask manufacturing process, the photomask blank is generally manufactured. Since it involves transport from the factory to the factory that manufactures the photomask, the photomask blank is stored in a predetermined container and transported. However, an increase in defects occurs during this transport, and as a result, There has been a problem that a defect needs to be corrected or an exposure failure occurs due to the defect.

  In particular, in order to meet the demand for further miniaturization of patterns, it is necessary to reduce even fine particles that have not been a problem in the past.

  The present invention has been made in order to solve the above-mentioned problems, and in order to provide an extremely high-quality photomask blank with few defects by preventing an increase in defects due to conveyance of the photomask blank. It is an object of the present invention to provide a photomask blank storage container and a support method capable of transporting the photomask blank while preventing the generation of particles that cause defects as much as possible.

  Conventionally, the cause of the increase in defects when storing and transporting a photomask blank coated with a resist used in semiconductor manufacturing etc. in a container is due to contamination of the storage container itself, or a lid when opening and closing the lid of the container It has been thought to be due to particles generated by friction with the container body.

  However, it was found that defects were increased before and after transport even if the influence of particles generated by dirt and friction of the container was removed as much as possible. In such a container, a fixing jig formed of a material such as a resin is usually used so that the resist film applied by moving the photomask blank during transportation does not come into contact with and damage the inner surface of the container. A method is adopted in which the photomask blank is fixed on the outer peripheral surface so as not to move.

  As a result of intensive investigations by paying attention to this point, the inventor is formed of a material such as a photomask blank and a resin by a force generated by vibration or the like applied to the stored photomask blank during transportation. It was found that rubbing occurred between the fixing jig and the high-hardness photomask blank, which caused particles to be generated by scraping off the low-hardness resin.

  Therefore, as a result of further studies, the inventor has a rectangular box-shaped container body that is open at the top, and a lid that covers the upper opening and is detachably attached to the upper end of the container body. When a photomask blank is stored inside the container, a synthetic resin support member and a synthetic resin spring member are respectively provided on the inner surfaces of a pair of opposing wall portions of the container, and these members press the photomask blank. The photomask blank is accommodated by supporting both sides of the photomask blank opposite to each other by the above-described members by the elastic force to be applied, and the support member and the spring member are respectively applied to the both sides of the photomask blank. If the spring force of the spring member is set so that the pressing force is 1.96 to 117.6 N, a photomask blur generated by vibration or the like generated during conveyance Click the fixture, i.e. to reduce the generation of particles due to rubbing between the photomask blank and the supporting member and the spring member, it found that it is possible to transport the photomask blank, the present invention has been accomplished.

That is, the present invention comprises a rectangular box-shaped container body that is open at the top, and a lid that covers the upper opening and is detachably attached to the upper end of the container body. A container to be stored, and a synthetic resin support member and a synthetic resin spring member are provided on the inner surfaces of a pair of opposing wall portions of the container, respectively, and the elastic force by which these members press the photomask blank By supporting the two opposite side surfaces of the photomask blank with the two members, the pressing force that the support member and the spring member respectively apply to the both side surfaces of the photomask blank in the container for storing the photomask blank. The photomask blank container and the upper part are open, wherein the spring force of the spring member is set to be 1.96 to 117.6N A rectangular box-shaped container body, and a lid that covers the upper open portion and is detachably attached to the upper end of the container body, and the photomask blank is stored inside the container that houses the photomask blank. A synthetic resin support member and a synthetic resin spring member are provided on the inner surfaces of a pair of opposing walls of the container, respectively, and the elastic force by which these members press the photomask blank is provided. In the method of supporting one side surfaces of the photomask blank facing each other by the two members, the pressing force applied to the both side surfaces of the photomask blank by the support member and the spring member is 1.96 to 117.6 N, respectively. Thus, there is provided a photomask blank supporting method, characterized in that the spring force of the spring member is set and supported.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the particle | grains causing a defect can be prevented as much as possible, a photomask blank can be conveyed, and a highly accurate photomask blank with very few defects can be provided. As a result, a photomask having a fine pattern can be formed with high accuracy, and fine pattern exposure is possible.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to the drawings.
The photomask blank storage container of the present invention comprises a rectangular box-shaped container body that is open at the top, and a lid that covers the upper opening and is detachably attached to the upper end of the container body. A photomask blank, preferably a 6-inch (about 152.4 mm) square photomask blank, for example, a photomask blank in which a light-shielding film or the like is formed on a substrate having a hardness higher than that of a resin such as a quartz substrate, particularly the light-shielding film or the like A container for storing a photomask blank on which a resist film is further formed, and provided with a support member made of a synthetic resin and a spring member made of a synthetic resin on the inner surfaces of a pair of wall portions facing each other, These members support one side surfaces of the photomask blank opposite to each other by the elastic force that presses the photomask blank, thereby allowing the photomask blank to In the container for storing the blank, the elastic force of the spring member is set so that the pressing force that the support member and the spring member respectively apply to both side surfaces of the photomask blank is 1.96 to 117.6N. It is.

  An example of such a container is a container as shown in FIGS. This container represents a 6-inch square photomask blank storage container. The container 1 includes a support member 21 therein, and the upper part is wider than the center part in the vertical direction and wider in the lateral direction (front and rear, left and right direction) than the lower part. A rectangular box-shaped container body 11 having a height of about 108.0 mm and a rectangular box-shaped lid body 12 having a height of about 3.25 inches (about 82.6 mm) having two spring members 22 and 22 inside. It consists of. The container body 11 and the lid body 12 are formed in such a size that the upper outer surface of the container body 11 and the lower inner surface of the lid body 12 are in contact with each other when the lid body 12 is attached to the container body 11. Has been.

  The container body 11 includes a support member 21 having a concave cross section made of synthetic resin so as to protrude upward from the inside thereof, a non-projecting portion of the outer side surface, a lower surface of the bottom plate 212, and an inner surface of the container body 11 respectively. It arrange | positions so that it may contact. The inner bottom surface of the container body 11 is provided with locking ridges 111 and 111 that are separated by the width in the width direction of the outer surface of the support member 21, and are supported by the locking ridges 111 and 111. The member 21 is fixed so as not to move in the width direction of the outer surface.

  Further, the interval between the inner side surfaces 211a and 211a of the side walls 211 and 211 of the support member 21 is formed to be narrower than 6 inches (narrow by about 16 mm), and the inner side surfaces 211a and 211a have a plurality of opposing groups (in the case of the figure). 5 sets) of grooves 211c and 211c having a U-shaped cross section are formed across the upper and lower ends of the inner side surfaces 211a and 211a. Further, the grooves 211c and 211c are slightly wider than the thickness of the photomask blank p, and the depth is slightly wider than the bottom of each of the grooves 211c and 211c facing each other than 6 inches (about 0.6 mm wider). ).

  When the photomask blank p is stored in the container 1, the photomask blank p is aligned with the two adjacent corners of the four corners of the photomask blank p in the grooves 211c and 211c, and the grooves are formed from the upper ends of the grooves 211c and 211c. 211c and 211c are guided and inserted. As a result, the photomask blank p is guided by the grooves 211c and 212c, and at the lower end of the grooves 211c and 211c, one entire surface of one set of parallel surfaces of the four outer peripheral surfaces of the photomask blank p is formed. The upper surface 212b of the bottom plate 212 of the support member 21 is in contact with the upper surface 212b.

  On the other hand, the lid 12 is detachably attached to the upper end of the container body so as to cover the upper open portion of the container body 11, and when the lid 12 is attached to the container body 11 inside the lid 12. Two spring members 22 and 22 made of synthetic resin are provided at positions above the side walls 211 and 211 of the support member 21, respectively. As shown in FIG. 5, the spring members 22, 22 include an upper plate 221, a side plate 222 provided so as to be orthogonal to the upper plate 221 downward from one end of the upper plate 221, and the upper plate 221 and the side plate 222. A plurality of support pieces 223 (five in the figure) having a width slightly larger than the thickness of the photomask blank p provided in a direction opposite to the upper plate 221 from a position where the crossing and the upper plate 221 are opposite to each other. The support piece 223 is disposed to be inclined downward with respect to the upper surface of the upper plate 221 by an angle θ (about 15 ° in the case of FIG. 5). In this case, the two spring members 22, 22 face each other with the support pieces 223, 223 facing each other so that the distance between the side plates 222, 222 is larger than 6 inches (about 2.5 mm wider). The upper surfaces of the plates 221 and 221 are attached to the inner surface of the top plate of the lid 12 and attached to the inside of the lid 12.

  The support pieces 223 and 223 are formed at equal intervals so that each of the support pieces 223 and 223 is positioned above the groove 211c formed in the support member 21 described above when the lid 12 is attached to the container body 11. Further, locking claws 223a and 223a are provided at both ends in the width direction at the front ends of the support pieces 223 and 223 so as to be spaced downward at substantially the same interval as the thickness of the photomask blank p, When the body 12 is attached to the container body 11, the two corners that are not inserted into the grooves 211c and 211c of the support member 21 are inserted between the locking claws 223a and 223a, and the locking claws 223a and 223a The movement of the photomask blank p in the thickness direction is regulated.

  Further, when the lid 12 is attached to the container main body 11, the support piece 223 of the spring member 22 has its lower surface 223b and the other surface of the parallel surface of the photomask blank p described above (of the support member 21). The other surface of the bottom plate 212 is in contact with the upper surface 212b of the bottom plate 212. The distance from the joint of the lower surface 223b with the side plate 222 to the upper surface 212b of the bottom plate 212 of the support member 21 is approximately the same. It has become 6 inches.

  In addition, locking pieces 121 and 121 are respectively provided toward the inner side of the lid body 12 at the center of the lower end of the pair of inner surfaces facing the lid body 12. When the lid 12 is attached to the container body 11, it engages with the locking grooves 112, 112 provided at the center of the lower ends of the pair of opposed outer surfaces of the upper portion formed in the wide width of the container body 11. The lid 12 is locked and fixed to the container body 11.

Next, a method for supporting and storing the photomask blank will be described.
First, the photomask blank p is placed on the support member 21 of the container body 11 described above, and the two adjacent corners of the four corners are aligned with the grooves 211c and 211c, so that the upper ends of the grooves 211c and 211c are changed to the grooves 211c and 211c. insert. Next, the lid 12 is attached to the container main body 11. At this time, the interval between the locking pieces 121, 121 provided on the lid 12 is narrower than the outer wall of the upper portion of the container main body 11. 11 is pushed into the lid 12 so as to slightly widen the gap between the locking pieces 121 and 121 of the lid 12.

  When the container body 11 is further pushed in, the locking claws 223a provided at the tips of the support pieces 223 and 223 are the two corners that are not inserted into the grooves 211c and 211c of the support member 21 of the photomask blank p, respectively. , 223a and abut against the lower surfaces 223b, 223b of the support pieces 223, 223. When the container body 11 is further pushed in from this state, the support pieces 223 and 223 are bent upward, and a resilient force is generated with respect to the photomask blank p. Due to this resilient force, the stored photomask blank p is stored. Are pressed and supported by the support member 21 and the support pieces 223 and 223 of the spring members 22 and 22 on both side surfaces of the photomask blank p facing each other.

  At the moving end of the lid 12, the support piece 223 of the spring member 22 is substantially horizontal so that almost the entire lower surface 223 b of the support piece 223 comes into contact with the photomask blank p and is provided on the lid 12. The engaging pieces 121, 121 thus engaged are engaged with engaging grooves 112, 112 provided in the container body 11, the lid body 12 is locked to the container body 11, and the elastic force of the support piece 223 is fixed. One side surfaces of the photomask blank p facing each other are pressed and sandwiched and supported by the upper surface 212b of the bottom plate 212 of the support member 21 and the lower surface 223b of the support piece 223.

  The photomask blank is supported and stored in the container by the method as described above. However, in the present invention, in the state where the photomask blank is sandwiched and supported by the support member and the spring member as described above. The pressing force that the support member and the spring member respectively apply to both side surfaces of the photomask blank (in the case where the photomask blank p is stored in the container shown in FIGS. 1 to 4, the outer peripheral surface of the photomask blank p is The pressing force at the portion of the support member 21 in contact with the upper surface 212b of the bottom plate 212 and the lower surface 223b of the support piece 223 of the spring member 22) is 1.96 to 117.6N, preferably 1.96 to 85N, more preferably The spring force of the spring member is set to be 2 to 58.8N. In the container shown in FIGS. 1 to 4, the elastic force of the spring member includes the thickness of the support piece 223 of the spring member 22, the inclination angle θ, the upper surface 212 b of the bottom plate 212 of the support member 21, and the spring member. It can be set by adjusting the distance from the lower surface 223b of the 22 support pieces 223.

  If the pressing force is set to exceed 117.6 N, when the photomask blank and the spring member rub against each other when the lid is attached to the container body, the spring member is too elastic and the hardness A high photomask blank scrapes off the low-hardness resin and generates particles. Further, if an excessive pressing force is applied, the photomask blank may be damaged. On the other hand, if the pressing force is less than 1.96 N, the support is insufficient, and the photomask blank vibrates greatly due to the force generated by the vibration applied to the stored photomask blank during transportation. As a result, dust is generated and defects are increased. In some cases, the resist film may be given fatal scratches that cannot be corrected.

  In addition, although the container as shown in FIGS. 1-4 was shown as an example of the container which can apply the storage container and support method of this invention suitably, the container which can apply the container and support method of this invention suitably Is not limited to the container as illustrated above, and its configuration can be changed as appropriate without departing from the scope of the present invention.

  Hereinafter, the present invention will be described with further specific experimental examples.

[Experimental example]
A photomask blank, in which a 70.0 nm chromium light-shielding film is formed on a 6-inch square quartz substrate by sputtering, and a 400.0 nm exposure resist is coated thereon, is placed in a container as shown in FIGS. The elastic force of the spring member is adjusted so that the pressing force that the support member and the spring member respectively apply to both side surfaces of the photomask blank becomes the values shown in Table 1 by storing the sheets and changing the elastic force of the spring member. 7 were prepared to support the photomask blank, and these were conveyed. The transportation is domestic transportation by truck, and the transportation distance is about 10 km.

In this case, the area of the portion where the photomask blank and the support member are in contact corresponds to any one of the outer peripheral surfaces of the photomask blank and is about 9.68 × 10 ⁻⁴ m ² . In addition, the pressing force that the support member and the spring member respectively apply to both side surfaces of the photomask blank is an operation of storing the photomask blank in the container body, attaching the lid to the container body, and closing the container. The measurement was carried out in a state of being loaded on a meter, and the force required for this closing operation was measured by a method for obtaining from the measured value by the above-mentioned weigh scale.

  The number of particles with a diameter of 0.2 to 1.0 μm before and after transportation on the photomask blank stored in each container was counted by an ArF laser beam scanning defect inspection apparatus, and the number of increase in the number of particles (defects) was averaged. Table 1 shows the measured values, and FIG. 6 shows a graph in which the average number of defect increases is plotted against the pressing force.

  When the pressing force is less than 1.96 N and the pressing force is 1 N, the photomask blank after transportation is not sufficiently supported at the time of transportation. Increased defects due to dust.

It is a storage container of the photomask blank of this invention, Comprising: It is a cross-sectional view which shows the state which accommodated the photomask blank, (A) is sectional drawing along the Z1-Z1 line | wire in FIG. FIG. 3B is a sectional view taken along line Z2-Z2 in FIG. FIG. 2 is a vertical cross-sectional view illustrating a state in which the photomask blank storage container of the present invention is stored, and (A) is a cross-sectional view taken along line X1-X1 in FIG. B) is a sectional view taken along line X2-X2 in FIG. FIG. 2 is a vertical cross-sectional view showing a photomask blank storage container of the present invention in a state in which the photomask blank is stored, (A) is a cross-sectional view taken along line Y1-Y1 in FIG. B) is a sectional view taken along line Y2-Y2 in FIG. It is a storage container of the photomask blank of this invention, Comprising: (A) is a longitudinal cross-sectional view which shows the state before accommodating and closing the photomask blank of FIG. 2 (A), (B) is FIG. 3 (B). It is a longitudinal cross-sectional view which shows the state before accommodating the photomask blank of and closing. It is a perspective view which shows the spring member of the storage container shown by FIGS. It is the graph which plotted the average value of the defect increase number with respect to pressing force in an experiment example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 11 Container main body 12 Cover body 21 Support member 22 Spring member 223 Support piece p Photomask blank

Claims (2)

  A container for storing a photomask blank inside, comprising: a rectangular box-shaped container body whose upper part is opened; and a lid body that covers the upper opening part and is detachably attached to the upper end part of the container body. A synthetic resin support member and a synthetic resin spring member are provided on the inner surfaces of the pair of wall portions facing each other, and the photomask blanks are opposed to each other by the elastic force with which the members press the photomask blank. By supporting the both side surfaces by the both members, the pressing force that the support member and the spring member respectively apply to the both side surfaces of the photomask blank in the container for storing the photomask blank is 1.96 to 117. A photomask blank storage container, wherein the spring force of the spring member is set to 6N. A rectangular box-shaped container body that is open at the top, and a lid that covers the upper opening and is detachably attached to the upper end of the container body. A method for supporting a mask blank, wherein a synthetic resin support member and a synthetic resin spring member are respectively provided on the inner surfaces of a pair of opposing wall portions of the container, and these members press the photomask blank. In the method in which one side surfaces of the photomask blank facing each other are supported by the two members by the generated force, the pressing force that the support member and the spring member respectively apply to both side surfaces of the photomask blank is 1.96 to 117. A method for supporting a photomask blank, comprising setting and supporting the elastic force of the spring member so as to be 6N.

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