JP2005283999A - Method for transporting photomask blank and method for screening photomask blank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for transporting a photomask blank while preventing defects as much as possible, the defects due to particles produced in the photomask blank caused by vibration or shock during transport, and to provide a method for efficiently screening a photomask blank having increased particles owing to vibration or shock during transport without performing defect inspection. <P>SOLUTION: The method for transporting a photomask blank is performed by controlling the whole transporting period in such a manner that the acceleration given to the container which houses the photomask blank is controlled to less than 25G for 50 msec during transport. The method for screening a photomask blank is characterized in that a photomask blank housed in a container subjected to ≥25G acceleration given to the container for any 50 msec period in the entire transporting period is screened out as a blank having increased particles. Thus, a photomask blank with extremely little defect and high accuracy is supplied. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photomask blank transport method and a photomask blank selection method used for manufacturing semiconductor integrated circuits and the like.

  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.

  So far, a method for reducing particles that give minute defects generated in a photomask blank manufacturing process, for example, a film forming process on a substrate, a cleaning process after film forming, a resist coating process, etc. 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.

  For example, when transporting a photomask blank or a photomask blank on which a resist film is formed, the photomask blank is fixed in a dedicated container so as not to move in the container, and the container is sealed with a light-shielding film. Prevent air pollution, moisture and light. Next, the sealed container is surrounded by a cushioning material, packed in a cardboard box, and then transported in an appropriate package according to the destination of transportation. During this transportation, vibration is given to the container and the photomask blank accommodated in the container, but if these are subjected to excessive impact, fine particles adhering to the container accommodating the photomask blank are contained. In the photomask blank on which the resist film is formed, the resist film attached to the outer peripheral surface of the photomask blank adheres to the resist film on the pattern formation surface of the photomask blank and becomes a defect. When many such phenomena occur, a clean photomask blank is manufactured as a product and shipped in a clean state, but when it arrives at the delivery destination, it becomes a photomask blank with many defects.

  In particular, it is desirable that the photomask blank on which the resist film is formed be defect-free, and careful attention is required for particles. However, in the past, it was known that vibration during transportation should be suppressed as much as possible while avoiding excessive shock, but the degree of occurrence of defects due to vibration and shock was not clear. Since we do not know how much it should be managed, and we do not know whether the transported photomask blank has been subjected to excessive impact during transportation, which increases the number of defects. Regardless of the history of vibration and shock during transportation, it was necessary to inspect all defects including those that were not subjected to excessive shock.

  The present invention has been made to solve the above-described problems. When a photomask blank is stored in a container and transported, defects due to particles generated in the photomask blank due to vibration or impact during transport are possible. It is an object of the present invention to provide a method capable of transporting while preventing as much as possible, and a method capable of efficiently sorting a photomask blank in which particles are increased due to vibration or impact during transport without defect inspection. To do.

  As a result of intensive studies in order to solve the above problems, the inventor has provided a synthetic resin support member and a synthetic resin spring member on the inner surfaces of a pair of opposing wall portions of a square box-shaped container, respectively. When these members are housed in a container for housing a photomask blank by supporting both sides of the photomask blank opposite to each other by the elastic force of pressing the photomask blank by the above-mentioned members. Furthermore, if the acceleration applied to the container while the photomask blank is housed and transported is managed and transported throughout the transport so that the acceleration during 50 msec is less than 25 G, vibration and shock during transport Can be transported while preventing defects caused by particles generated in the photomask blank as much as possible. If a photomask blank stored in a container whose acceleration was 25 G or more for any 50 msec over the entire conveyance was selected as an increase in particles, vibration and shock during conveyance The present inventors have found that photomask blanks with increased particles can be efficiently sorted without defect inspection, and have made the present invention.

That is, the present invention provides the following photomask blank transport method and photomask blank selection method.
Claim 1:
A container for storing a photomask blank, 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 a rectangular box-shaped container, respectively, and these members are photomasks The photomask blank is stored and transported in a container for storing the photomask blank by supporting the opposite side surfaces of the photomask blank opposite to each other by the above-mentioned members by the elastic force of pressing the blank. ,
Transport of photomask blank characterized in that the acceleration given to the container during storage and transport of the photomask blank is managed and transported throughout the transport so that the acceleration during 50 msec is less than 25G. Method.
Claim 2:
A container for storing a photomask blank, 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 a rectangular box-shaped container, respectively, and these members are photomasks A method for selecting a photomask blank stored and transported in a container for storing the photomask blank by supporting both sides of the photomask blank opposite to each other by the above-mentioned members by the elastic force of pressing the blank. There,
Particles increased in the photomask blank stored in the container in which the acceleration applied to the container during storage and transport of the photomask blank was 25 G or more for any 50 msec during transport A photomask blank sorting method characterized by sorting as a product.

  ADVANTAGE OF THE INVENTION According to this invention, when storing a photomask blank in a container and conveying, the defect by the particle which generate | occur | produces in the photomask blank by the vibration and impact during conveyance can be prevented as much as possible, and can be conveyed. In addition, it is possible to efficiently sort a photomask blank in which particles are increased due to vibration or impact during conveyance without performing defect inspection. As a result, a highly accurate photomask blank with extremely few defects can be provided, and a photomask having a fine pattern can be formed with high precision from these, thereby enabling fine pattern exposure.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail.
The present invention is a container for storing a photomask blank, and is a rectangular box-shaped container, preferably a rectangular box-shaped container body opened upward, and detachably attached to the upper end of the container body covering the upper open part. 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 a container having a lid to be adhered, and the members press the photomask blank. The photomask blank is stored and transported in a container for storing the photomask blank by supporting one side surfaces of the photomask blank facing each other by the above-mentioned members by the generated force. Watari the acceleration applied to the container during the conveying, the whole being transported so acceleration is less than 25G (about 245m / s ²⁾ between 50msec It is intended to transport and supervises as.

Further, the present invention is a container for storing a photomask blank, which is a rectangular box-shaped container, preferably a rectangular box-shaped container body opened upward, and attached to and detached from the upper end of the container body covering the upper open part. A synthetic resin supporting member and a synthetic resin spring member are respectively provided on the inner surfaces of a pair of opposing wall portions of a container having a lid that is freely attached, and these members press the photomask blank. The photomask blank is stored in a container for storing the photomask blank and supported by the above-mentioned members by supporting both side surfaces of the photomask blank opposite to each other by the elastic force of the photomask blank. The acceleration applied to the container while the mask blank is stored and transported is 25 G (about 245 m) during any 50 msec during transport. The s ²⁾ or more in a photomask blank that has been housed in a container, is intended to select as the particles has increased.

  In any of the methods of the present invention, the photomask blank includes both a photomask blank in which a resist film is formed on a pattern formation surface and a photomask blank in which a resist film is not formed.

  In any of the methods of the present invention, the photomask blank is housed in a container. Examples of the container suitable for these methods include containers as shown in FIGS. This container represents a 6-inch square photomask blank storage container. The container 1 includes guide members 211 and 211 and support members 212 and 212 therein, and an upper portion that is wider from the center portion in the vertical direction and wider in the lateral direction (front and rear, left and right directions) than the lower portion is open. The rectangular box-shaped container body 11 having a height of about 4.25 inches (about 108.0 mm) and two spring members 22, 22 inside have a height of 3.25 inches (about 82.6 mm). And a quadrangular box-shaped lid body 12. 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 is provided with a guide groove 211c (described later) into which a peripheral edge portion along an arbitrary set of parallel surfaces (one parallel surface) among the four outer peripheral surfaces of the photomask blank p is inserted. Plate-shaped guide members 211 and 211 made of synthetic resin are provided by being bonded to a pair of inner surfaces facing each other so as to protrude upward from the inside of the container body 11, and at the center of the inner bottom surface of the container body 11, Rail-like support members 212 and 212 made of synthetic resin that support and support the photomask blank p on one surface side of the other parallel surface with respect to the one parallel surface of the photomask blank p are guide members 211 and 211. Are arranged in parallel at a predetermined distance.

  In addition, the gap between the inner side surfaces 211a and 211a of the guide members 211 and 211 is narrower than 6 inches (nearly 16 mm), and the inner side surfaces 211a and 211a have a plurality of opposing groups (five sets in the figure). Grooves 211c and 211c having a U-shaped cross section are formed over 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 211c and contacts the rail-like support members 212 and 212 on one surface side of the other parallel surface with respect to the one parallel surface of the photomask blank p. It is inserted until it touches. On the other hand, the support members 212 and 212 are provided with support grooves 212c (in the case of the figure), which are composed of a bottom surface 212b and tapered surfaces 212d and 212d that are inclined upward from the bottom surface 212b at the same intervals as the grooves 211c and 211c. The photomask blank p is opposed to one side of the other parallel surface with respect to the one parallel surface in the thickness direction of the photomask blank p. The two sides to be in contact with the tapered surfaces 212d and 212d, respectively.

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 guide members 211 and 211, respectively. As shown in FIG. 5, the spring members 22, 22 are located at an angle θ ₂ (about 15 ° in the case of FIG. 5) from the vertical direction with respect to the upper plate 221 and the lower surface of the upper plate 221 from one end of the upper plate 221. A plurality of side plates 222 having a length of about 1 inch (five in the figure) provided at equal intervals so as to incline in a direction away from the plate 211, and the upper plate from the position where the upper plate 221 and the side plate 222 intersect. A plurality of support pieces 223 (five in the figure) having a width slightly larger than the thickness of the photomask blank p provided at equal intervals in the direction opposite to 221 and a length of about 1 inch. 223 is disposed to be inclined downward by an angle θ ₁ (about 15 ° in the case of FIG. 5) with respect to the upper surface of the upper plate 221. In this case, the two spring members 22 and 22 are arranged so that the support pieces 223 and 223 face each other so that the distance between the tips of the side plates 222 and 222 is slightly wider than 6 inches (about 2.5 mm wider). The upper surfaces of the upper 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 side plates 222 and 222 of the spring members 22 and 22 and the support pieces 223 and 223 are formed by the grooves 211c and the grooves 211c formed in the guide members 211 and 221 described above when the lid body 12 is attached to the container body 11. The support claws 223a and 223a are formed at equal intervals so that each of them is positioned above 211c, and the locking claws 223a and 223a are substantially the same as the thickness of the photomask blank p at both ends of the support pieces 223 and 223 in the width direction. The two corners that are not inserted into the grooves 211c and 211c of the guide members 211 and 211 when the lid body 12 is attached to the container body 11 are separated from each other. Inserted between the locking claws 223a and 223a, the movement of the photomask blank p in the thickness direction is regulated by the locking claws 223a and 223a.

  Further, when the lid 12 is attached to the container body 11, the support piece 223 of the spring member 22 has its tip and the other surface (support) of the other parallel surface of the photomask blank p described above. The taper surfaces 212d and 212d of the member 212 are in contact with the other surface of one surface having two sides in contact with the taper surfaces 212d and 212d.

  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 in this container will be described.
First, the photomask blank p is placed on the guide members 211 and 211 of the container body 11 described above, and two adjacent corners of the four corners are aligned with the grooves 211c and 211c, so that the grooves 211c and 211c Insert into 211c. 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 two corners that are not inserted into the grooves 211c and 211c of the guide members 211 and 211 of the photomask blank p are provided at the tips of the support pieces 223 and 223, respectively. While being inserted between the claws 223a and 223a, the other surface of the other parallel surface of the photomask blank p comes into contact with the tips of the support pieces 223 and 223. When the container body 11 is further pushed from this state, the support pieces 223 and 223 are elastically deformed upward, and a resilient force is generated with respect to the photomask blank p, and the accommodated photomask blank is generated by this resilient force. p is pressed and supported by the supporting members 212 and 212 and the supporting pieces 223 and 223 of the spring members 22 and 22 from the opposite side surfaces (the other parallel surface) of the photomask blank p. At the same time, the support pieces 223 and 223 are elastically deformed and bent upward, whereby the front ends of the side plates 222 and 222 are moved inward to reduce the distance therebetween, and the photomask blank p is opposed to each other. The photomask blank p is held in contact with two side surfaces (the one parallel surface).

  At the moving end of the lid 12, the photomask blank p is supported in the vicinity of the two corners that are not inserted into the grooves 211 c and 211 c by the support pieces 223 and 223 of the spring members 22 and 22 and the side plates 222 and 222. At the same time, the locking pieces 121, 121 provided on the lid body 12 engage with the locking grooves 112, 112 provided on the container body 11, and the lid body 12 is locked to the container body 11, thereby supporting pieces The elastic forces of 223 and 223 are fixed, and are pressed by the supporting members 212 and 212 and the supporting pieces 223 and 223 from the opposite side surfaces (the other parallel surface) of the photomask blank p, respectively. It is sandwiched and supported.

  In the transport method of the present invention, the photomask blank is stored and transported in the container as described above. In this case, the acceleration applied to the container while the photomask blank is stored and transported is an acceleration of 50 msec. Is controlled and transported throughout the transport so that the value is less than 25G. Specifically, for example, a shockwatch label whose indicator changes color when an acceleration exceeding a predetermined value is given at a predetermined time on a container or a cardboard box in which a container is further packed is attached for 50 msec during transportation. Is conveyed so that the acceleration of the motor does not exceed 25 G, that is, the indicator does not change color. As such a shock watch label, a commercially available product such as Shock Watch Label L-65 manufactured by Sumitomo 3M Co. can be used. By controlling the acceleration in this way and transporting, defects due to particles generated in the photomask blank due to vibrations and impacts during transport can be prevented as much as possible.

  Further, in the sorting method of the present invention, the photomask blank that has been stored and transported in the container as described above is sorted. In this case, the photomask blank is stored and transported to the container while being transported. The photomask blank stored in the container whose acceleration is 25 G or more in any 50 msec over the entire conveyance is selected as an increase in particles. Specifically, a shockwatch label whose indicator changes color when an acceleration exceeding a predetermined value is given at a predetermined time on a container or a cardboard box in which the container is further packed, is accelerated for 50 msec during transportation. Are selected as those with increased particles. As such a shock watch label, the above-mentioned commercial item can be used. By sorting out those that have received an excessive impact by such a method, it is possible to efficiently sort out a photomask blank in which particles have increased due to vibrations and impacts during transport without inspecting for defects.

  In addition, although the container as shown in FIGS. 1-4 was shown as an example of the container which can apply the conveyance method and the selection method of this invention suitably, it is not limited to the container as illustrated above. The configuration can be appropriately changed without changing the gist of the present invention.

  Hereinafter, the present invention will be described in more detail with reference to experimental examples.

[Experimental Example 1]
The number of particles in 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 further coated with a 400.0 nm resist for exposure is set to GM- manufactured by Hitachi Electronics Engineering Co., Ltd. Measurement was performed with a 1000 inspection machine (the same applies to the measurement of the number of particles in the following example), and five of these were stored in a cleaned container as shown in FIGS. Next, the container was double-wrapped with a transparent resin film and an aluminum film, and this was put into a cardboard box provided with an inflatable cushion material on the inner surface, and then taped and packed. A shock watch label L-65 manufactured by Sumitomo 3M was attached to the outer surface of the cardboard box. In this label, when an acceleration of 25 G (about 245 m / s ² ) or more is given for 50 msec, the indicator turns red.

  Next, when the cardboard box packed with the container containing the photomask blank was dropped and the minimum height at which the indicator developed color was examined, it was 50 cm. Then, the cardboard box which packed the container which accommodated the photomask blank from 50 cm in height was dropped 10 times. The shockwatch label was colored red by this operation. The number of particles on the photomask blank after the above operation was measured. Table 1 shows the increase number (average value) of the number of particles before and after the dropping operation.

[Experiment 2]
The number of particles on the photomask blank before and after the dropping operation was measured in the same manner as in Experimental Example 1 except that the photomask blank was replaced with one not coated with a resist. Table 1 shows the increase number (average value) of the number of particles before and after the dropping operation.

[Experiment 3]
As in Experimental Example 1, a photomask blank coated with a resist is stored in a container, the container is packed in a cardboard box, and a shock watch label is similarly attached. The vibration operation continuously applied for 1 min was set as one cycle, and the total was repeated 10 cycles. The shockwatch label did not develop color by this operation. The number of particles on the photomask blank after the above operation was measured. Table 1 shows the increase number (average value) of the number of particles before and after the vibration operation.

[Experimental Example 4]
The number of particles on the photomask blank before and after the vibration operation was measured in the same manner as in Experimental Example 3 except that the photomask blank was replaced with one not coated with a resist. Table 1 shows the increase number (average value) of the number of particles before and after the vibration operation.

[Experimental Example 5]
As in Experimental Example 1, a photomask blank coated with a resist is stored in a container, the container is packed in a cardboard box, and a shockwatch label is similarly attached. (Truck and Aircraft), one of the two shockwatch labels turned red.

  Next, the number of particles on the photomask blank was measured for each of the photomask blank in the cardboard box where the shockwatch label was not discolored and the photomask blank in the cardboard box where the shockwatch label was not discolored. Table 2 shows the increase number (average value) of the number of particles before and after transportation.

[Experimental Example 6]
As in Experimental Example 2, a photomask blank not coated with a resist is stored in a container, the container is packed in a cardboard box, and a shockwatch label is similarly attached. Upon reciprocal transportation (truck and aircraft), one of the two shockwatch labels turned red.

  Next, the number of particles on the photomask blank was measured for each of the photomask blank in the cardboard box where the shockwatch label was not discolored and the photomask blank in the cardboard box where the shockwatch label was not discolored. Table 2 shows the increase number (average value) of the number of particles before and after transportation.

FIG. 4 is a cross-sectional view showing a photomask blank storage container to which the method of the present invention can be suitably applied, and shows a state in which the photomask blank is stored, and (A) is a Z1-Z1 line in FIG. FIG. 3B is a sectional view taken along line Z2-Z2 in FIG. FIG. 2 is a vertical cross-sectional view showing a photomask blank storage container to which the method of the present invention can be suitably applied, and shows a state in which the photomask blank is stored. FIG. 1 (A) is a line X1-X1 in FIG. (B) is sectional drawing which followed the X2-X2 line | wire in FIG. 1 (A). FIG. 2 is a vertical cross-sectional view showing a photomask blank storage container to which the method of the present invention can be suitably applied, and shows a state in which the photomask blank is stored, and (A) is a Y1-Y1 line in FIG. (B) is sectional drawing which followed the Y2-Y2 line | wire in FIG. 1 (A). FIG. 2 is a photomask blank storage container to which the method of the present invention can be suitably applied, wherein FIG. 2A is a longitudinal sectional view showing a state before the photomask blank of FIG. 2A is stored and closed; FIG. 4 is a longitudinal sectional view showing a state before the photomask blank of FIG. 3B is stored and closed. It is a perspective view which shows the spring member of the storage container shown by FIGS.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 11 Container main body 12 Cover body 211 Guide member 212 Support member 22 Spring member 221 Upper plate 222 Side plate 223 Support piece p Photomask blank

Claims (2)

A container for storing a photomask blank, 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 a rectangular box-shaped container, respectively, and these members are photomasks The photomask blank is stored and transported in a container for storing the photomask blank by supporting the opposite side surfaces of the photomask blank opposite to each other by the above-mentioned members by the elastic force of pressing the blank. ,
Transport of photomask blank characterized in that the acceleration given to the container during storage and transport of the photomask blank is managed and transported throughout the transport so that the acceleration during 50 msec is less than 25G. Method. A container for storing a photomask blank, 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 a rectangular box-shaped container, respectively, and these members are photomasks A method for selecting a photomask blank stored and transported in a container for storing the photomask blank by supporting both sides of the photomask blank opposite to each other by the above-mentioned members by the elastic force of pressing the blank. There,
Particles increased in the photomask blank stored in the container in which the acceleration applied to the container during storage and transport of the photomask blank was 25 G or more for any 50 msec during transport A photomask blank sorting method characterized by sorting as a product.

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