JP2005289432A - Substrate storage case - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate storage case which stores a substrate such as a mask and a photo mask blank and effectively prevent deposition of dust or the like on the stored substrate. <P>SOLUTION: The substrate storage case to store the substrate has at least a case body and a case lid. The substrate storage case has a double structure in which inner portions facing the stored substrate of the case lid and the case body are non-conductive, and outer portions facing the outer side are conductive. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a substrate storage case for storing substrates such as masks and photomask blanks used in the manufacture of semiconductor devices.

  In recent years, integrated circuits (ICs) formed on a semiconductor wafer such as a silicon wafer have been increasingly highly integrated, and large-scale integrated circuits (LSIs) have been realized. For this reason, in the lithography process in the LSI manufacturing, the mask pattern of the mask used for exposure has been miniaturized. Here, the photomask blank is a substrate in which a light shielding film such as Cr or MoSi and a phase shift film are formed on a quartz glass body by a method such as sputtering. Then, a resist material is applied to this photomask blank by a spin coating method or the like to form a resist, and a mask pattern is formed through means such as pattern exposure and development, which is called a mask.

  If dust or the like adheres to the mask pattern of such an exposure mask, it is projected onto a semiconductor wafer to become a defect, resulting in a defective product of an LSI to be manufactured. In addition, if dust or the like adheres to the photomask blank, there is a problem that a desired mask pattern cannot be engraved on the photomask blank during mask manufacture. For this reason, if exposure is performed using such a mask, similarly, an LSI product to be manufactured is defective.

  These substrates such as masks and photomask blanks are usually stored in a substrate storage case and stored, stored, transported, and the like. However, at this time, dust or the like may enter the case from the gap between the case main body and the case lid of the substrate storage case. This is one of the causes of dust and the like adhering to the substrate.

  Therefore, a substrate storage case has been proposed in which the case can be sealed without gaps and the case main body and the case lid can be easily removed in order to prevent dust and the like from entering the case (see, for example, Patent Document 1). However, when this board storage case is used, the case sealability is improved, so that dust and the like can be prevented from entering during sealing. As a result, there arises a problem that dust or the like adheres to a substrate such as a mask or a photomask blank in the case.

  In addition, there has been proposed a substrate storage case in which the case inner portion is made sticky so that it does not adhere to the mask or photomask blanks even if dust or the like enters the case. However, when this substrate storage case was used, dust that entered the case and floated did not all adhere to the inner part of the case, but often adhered to the mask and photomask blanks. It was not enough as a countermeasure against dust.

JP 2001-154341 A

  The present invention has been made in view of such problems. For example, the present invention is a substrate storage case for storing substrates such as masks and photomask blanks, and can effectively prevent dust and the like from adhering to the stored substrates. An object is to provide a substrate storage case.

  The present invention has been made to solve the above problems, and is a substrate storage case for storing a substrate, which has at least a case main body and a case lid, and the case cover and the case main body are arranged on the substrate to be stored. Provided is a substrate storage case having a double structure in which an inner portion facing is non-conductive and an outer portion facing outward is conductive.

  In the substrate storage case of the present invention, since the outer portions of the case main body and the case lid are conductive, the generation of static electricity is prevented in the outer portions, and it is difficult to suck surrounding dust and the like. Therefore, it is possible to reduce the amount of dust or the like that adheres to the outside of the case or enters the case. Further, since the case lid and the inner portion of the case body are non-conductive, static electricity is generated in the inner portion, and dust or the like floating in the case is easily sucked inside the case body and the case lid. Thus, in the substrate storage case of the present invention, the amount of dust and the like entering the case is very small, and even if dust or the like enters the case, it adheres to the inside of the case body and the case lid. Almost no adhesion to the substrate. Therefore, by using the double-layer substrate storage case of the present invention, it is possible to effectively prevent dust and the like from adhering to the stored substrate, and to keep the substrate in a very clean state. it can.

  In this case, the conductive outer portion preferably has a surface specific resistance of 10 MΩ · cm or less.

  Thus, if the surface specific resistance of the outer portion of the substrate storage case is 10 MΩ · cm or less, the generation of static electricity can be prevented more reliably. Accordingly, the amount of dust or the like that adheres to the outside of the case or enters the case can be greatly reduced.

  Further, the non-conductive inner portion preferably has a surface specific resistance of 20 MΩ · cm or more.

  Thus, if the surface specific resistance of the inner part of the substrate storage case is 20 MΩ · cm or more, static electricity is very likely to occur. Therefore, dust or the like floating in the case can be sufficiently sucked into the inner portion of the case body and the case lid.

  In the substrate storage case of the present invention, it is preferable that the substrate to be stored is a mask or a photomask blank.

  In recent years, when dust or the like adheres to a mask or a photomask blank, it is projected onto a semiconductor wafer to become a defect, resulting in a product defect of a semiconductor device to be manufactured. However, by using the substrate storage case of the present invention, it is possible to effectively prevent dust and the like from adhering to the mask and photomask blanks being stored in the case.

  As described above, according to the present invention, since the inner portion of the case lid and the case main body is non-conductive and the outer portion is conductive, a double-layered substrate storage case is provided. It is possible to effectively prevent dust and the like from adhering.

Hereinafter, although embodiment of this invention is described, this invention is not limited to these.
FIG. 1 is a schematic cross-sectional view showing a substrate storage case of the present invention. The substrate storage case 1 includes a case main body 2, a case lid 3, and an inner case 5 having a substrate pressing portion. Furthermore, the case lid 3 and the case body 2 of the substrate storage case 1 have a double structure. That is, the inner part (dashed line part) 6 facing the substrate 4 to be stored is non-conductive, and the outer part (solid line part) 7 facing the outside is conductive.
The substrate storage case 1 can store five substrates 4 at equal intervals. And when the board | substrate 4 is accommodated in the board | substrate storage case 1 for preservation | save, storage, conveyance, etc., the board | substrate storage case 1 usually winds a tape around an opening-and-closing part so that it may not be influenced by an external environment. Sealed by.

  If the outer portion 7 is conductive like the substrate storage case 1 of the present invention, the outer portion 7 can effectively prevent the generation of static electricity. Accordingly, the outer portion 7 is difficult to suck the surrounding dust and the like, and adheres to the surface of the outer portion 7 or the amount of dust and the like that enters the substrate storage case 1 from the gap between the case lid 3 and the case body 2. Can be reduced. Furthermore, since the case lid 3 and the inner portion 6 of the case body 2 are non-conductive, the inner portion 6 can promote the generation of static electricity. Accordingly, it becomes easy to suck dust and the like floating in the substrate storage case 1 into the case body 2 and the inner portion 6 of the case lid 3. As described above, the substrate storage case 1 of the present invention can greatly reduce the amount of dust and the like entering the case 1, and the case main body 2 and the case lid even if dust or the like enters the case 1. 3 adheres to the inner portion 6 of the substrate 3, and therefore hardly adheres to the substrate 4. Therefore, by using the double-layer substrate storage case of the present invention, it is possible to effectively prevent dust and the like from adhering to the stored substrate, and to keep the substrate in a very clean state. it can.

  Examples of the non-conductive material of the inner portion 6 include ABS (acrylonitrile-butadiene-styrene) resin, PP (polypropylene), PMMA (polymethyl methacrylate), PE (polyethylene), and the like. Examples of the conductive material for the outer portion 7 include a material obtained by kneading a conductive material such as carbon into ABS resin, PP, PMMA, PE, or the like.

  In addition, the conductive outer portion 7 of the case body 2 and the case lid 3 preferably has a surface specific resistance of 10 MΩ · cm or less. Thus, by setting the surface specific resistance of the outer portion 7 to 10 MΩ · cm or less, it is possible to sufficiently suppress the generation of static electricity that attracts dust and the like from the surroundings.

  The non-conductive inner portions of the case body 2 and the case lid 3 preferably have a surface specific resistance of 20 MΩ · cm or more. Thus, by setting the surface specific resistance of the inner portion 6 to 20 MΩ · cm or more, static electricity that can attract dust and the like in the case can be more easily generated.

  In the present invention, the conductive outer portion and the non-conductive inner portion may have a double structure by using a so-called composite material obtained by laminating a conductive material and a non-conductive material. The outer member and the non-conductive inner member may be formed separately and overlapped to form a double structure.

  The substrate storage case of the present invention is optimal for storing substrates such as masks and photomask blanks. In recent years, when dust or the like adheres to a mask or a photomask blank, it is projected onto a semiconductor wafer to become a defect, resulting in a product defect of a semiconductor device to be manufactured. However, by using the substrate storage case of the present invention, it is possible to effectively prevent dust and the like from adhering to the mask and photomask blanks being stored in the case.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these.
(Example 1)
A double-layered substrate storage case as shown in FIG. 1 was prepared. In this substrate storage case 1, the outer portion 7 of the case lid 3 and the case main body 2 is made of ABS resin (8 MΩ · cm) kneaded with carbon powder, and the inner portion 6 is made of non-conductive ABS. Resin (20 MΩ · cm or more) was used. Then, 5 pieces of photomask blanks (152 mm (6 inches) × 152 mm (6 inches) × 6.35 mm (0.25 inches) t) are put in this substrate storage case, and the lid is covered so that outside air does not enter. Sealed. Further, the sealed substrate storage case was put in a nylon bag and put in a cardboard box together with a cushioning material. And then, this was sent 700km by land.
Before and after this land transport, the amount of dust and the like adhering to the photomask blanks was measured as the number of defects with a Hitachi Deco defect measuring device (GM-1000). The number of defects increased before and after land transportation was obtained. The total number of photomask blanks measured was 35, and the measured area was within 142 mm □. The result is shown in FIG.

(Comparative Example 1)
Substrate storage case as in Example 1, except that the entire case lid and case body were made of a substrate storage case made of ABS resin (8 MΩ · cm) kneaded with carbon powder. The photomask blanks were stored and transported to land. The number of defects increased before and after land transportation was obtained. The result is shown in FIG.

(Comparative Example 2)
Photomask blanks are stored in the substrate storage case in the same manner as in Example 1 except that a substrate storage case made of non-conductive ABS resin (20 MΩ · cm or more) is used for the entire case lid and case body. And landed. The number of defects increased before and after land transportation was obtained. The result is shown in FIG.

  As can be seen from FIG. 2, when the double-layered substrate storage case of the present invention is used, the amount of dust and the like adhering to the photomask blank during land transportation is extremely small. On the other hand, as in Comparative Example 2, when the case main body and the case lid of the substrate storage case are made of only a non-conductive material, it can be seen that the amount of dust and the like adhering to the photomask blank during land transportation is extremely large. This is presumably because the case generated static electricity during land transportation, attracted a large amount of surrounding dust, etc., and entered the case and adhered to the photomask blanks. Further, as in Comparative Example 1, when the case main body and the case lid of the substrate storage case are made of only a conductive material, the amount of dust and the like attached to the photomask blank during land transportation is compared with Comparative Example 2, Although it is decreasing slightly, it turns out that it is still many. This is because the case can be prevented from generating static electricity during land transportation, so that the amount of dust and the like that is attracted and enters the case can be reduced, but the dust that has entered the case is not the case. This is thought to be because a large amount of the photomask blanks adhered.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

It is a schematic sectional drawing which shows the one aspect | mode of the board | substrate storage case of this invention. It is the graph which compared the defect increase number of the photomask blanks before and after land transportation (Example 1, Comparative Examples 1 and 2).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate storage case, 2 ... Case main body, 3 ... Case lid, 4 ... Substrate,
5 ... inner case, 6 ... inner part, 7 ... outer part.

Claims (4)

  A substrate storage case for storing a substrate, which has at least a case main body and a case cover, and the case cover and the case main body are non-conductive on the inner side facing the substrate to be stored, and on the outer side facing outward A substrate storage case characterized in that the portion has a double structure having conductivity.   The substrate storage case according to claim 1, wherein the conductive outer portion has a surface specific resistance of 10 MΩ · cm or less.   The substrate storage case according to claim 1, wherein the non-conductive inner portion has a surface specific resistance of 20 MΩ · cm or more.   The substrate storage case according to claim 1, wherein the substrate to be stored is a mask or a photomask blank.

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