JP4796946B2 - Pellicle storage container - Google Patents

Description

  The present invention relates to a pellicle storage container for storing, storing, and transporting a pellicle for lithography used as a dust remover when manufacturing a semiconductor device, a printed circuit board, a liquid crystal display, or the like.

  In the manufacture of semiconductors such as LSI and VLSI, or the manufacture of liquid crystal displays and the like, a pattern is produced by irradiating a semiconductor wafer or liquid crystal master plate with light. A photomask or reticle (hereinafter simply referred to as a photomask) used at this time is used. If dust adheres to the surface, the dust will absorb light or bend the light, so the transferred pattern will be deformed, the edges will be sticky, the ground will be black, etc. There was a problem that dimensions, quality, appearance, etc. were impaired.

  For this reason, these operations are usually performed in a clean room, but it is still difficult to keep the photomask clean. Therefore, exposure is performed after a pellicle is attached to the surface of the photomask to prevent dust. In this case, the foreign matter does not adhere directly to the surface of the photomask but adheres to the pellicle. Therefore, if the focus is set on the pattern of the photomask during lithography, the foreign matter on the pellicle becomes irrelevant to the transfer.

  In general, a pellicle has a transparent pellicle film made of nitrocellulose, cellulose acetate, fluororesin, or the like that transmits light well, and is attached or bonded to the upper end surface of a pellicle frame made of aluminum, stainless steel, polyethylene, or the like. Further, an adhesive layer made of polybuden resin, polyvinyl acetate resin, acrylic resin or the like for mounting on a photomask, and a release layer (separator) for the purpose of protecting the adhesive layer are provided at the lower end of the pellicle frame.

  However, after attaching the pellicle to the mask, there is a foreign substance intrusion effect from the outside to the inside of the closed space formed by them, but when the foreign substance adheres to the pellicle itself and it is inside the closed space, It is difficult to prevent foreign matter from adhering to the photomask. For this reason, not only the pellicle itself is required to have high cleanliness, but also the pellicle storage container used for storage and transportation is strongly required to have a performance capable of maintaining the cleanliness. Specifically, it has excellent antistatic performance, a material that generates little dust even when rubbed, a structure that prevents contact between the pellicle and components as much as possible, and a highly rigid structure that prevents deformation when external force is applied. Required.

  The pellicle storage container is usually manufactured by injection molding or vacuum forming a resin such as ABS or acrylic. These molding methods are used because the surface is smooth and there is little risk of adhesion of foreign matter and dust generation, because there is no joint and there is no risk of dust generation and foreign matter intrusion due to integral molding, even in complicated shapes This is because there are advantages that it can be easily manufactured and that it is excellent in mass productivity and can be reduced in cost.

  Storage containers for semiconductor and printed circuit board pellicles have outer side lengths of approximately 200 to 300 mm, and these are usually manufactured using injection molding. As described above, in order to maintain the cleanliness of the pellicle storage container, it is required to have high rigidity that is difficult to be deformed even when an external force is applied. However, in the pellicle storage container having a side length of 200 to 300 mm, the problem of rigidity is Few. This is because, in addition to being small in size and easy to ensure rigidity, it is easy to locally change the thickness in injection molding, and thick reinforcement can be added to important points.

On the other hand, a large pellicle storage container having a side length exceeding 500 mm mainly used for a liquid crystal pellicle is generally a vacuum-formed synthetic resin sheet such as ABS or acrylic. This is because, in the injection molding in which the resin is injected at a high speed into the mold from one or several gates, the resin flow distance is too long, which makes it difficult to manufacture. In vacuum molding, a large product can be easily molded simply by placing a heated resin sheet on a mold and vacuuming.
However, in the case of vacuum forming, there is a problem that a thick material cannot be formed, and although ribs can be reinforced to some extent, basically a sheet with the same thickness is simply folded, so that it is difficult to make a highly rigid material.

Examples of such ribs are illustrated in, for example, Patent Document 1 regarding the container body.
The reinforcing ribs that have been used in the past are basically X-shaped provided in the direction connecting the diagonal lines 54a and 54b of the outer shape as shown in FIG. However, in the X-shaped ribs that intersect each other, the rigidity in the torsional direction is extremely reduced due to the presence of the intersecting portion (continuous portion) 59, and as shown in FIG. The tray twists along one of the diagonal lines and bends so that the opposite vertex approaches.

In such a rib manufactured by the vacuum forming method, the rib secures rigidity by the bent vertical surface, but this vertical surface is cut by another intersecting (connected) rib. It is because it ends. And this rib not only cuts the other party's rib and kills the effect, but also becomes a bending point (line) itself and increases the degree of deformation.
For this reason, sufficient rigidity cannot be ensured only by the ribs, and for example, as shown in Patent Document 2, fastening with another reinforcing body has ensured rigidity.

JP 2000-173887 A Japanese Patent Application No. 2005-081533

As described above, when another reinforcing body is used, a sufficient strength can be obtained, but various inconveniences occur in operation. The largest one is an increase in weight. In most cases, the reinforcing body is heavier than the container body in order to ensure sufficient rigidity. And the increase in weight makes handling extremely inconvenient in situations such as packing and transportation.
Moreover, not only the reinforcing body itself but also the parts for fastening the reinforcing body to the container body are required, and the man-hours for assembling it to the container body are also required. To increase. In addition to this, there is a problem concerning cleanliness that it is difficult to clean the gap between the reinforcing body and the container body.

However, there has been no pellicle storage container that has sufficient rigidity only with the container body without using a reinforcing body.
From the above, the object of the present invention is a lightweight and low-weight, with sufficient rigidity to withstand external forces during storage and transportation and to prevent foreign matter from adhering to the pellicle stored inside without using other reinforcing bodies. It is to provide a pellicle storage container at a low cost.

The pellicle storage container of the present invention is a pellicle storage container comprising a container main body on which the pellicle is placed, and a lid body that covers the pellicle and engages and locks at the periphery of the container main body. The container body is provided with a plurality of ribs that are formed and cross a diagonal line of the outer shape of the container body and do not intersect with other ribs (Claim 1).
Here, it is preferable that an angle formed with a diagonal line traversed by the rib is 30 degrees or more (Claim 2). The ribs need not intersect the other ribs, but may be connected to a pedestal on which the other ribs or pellicle is placed at the end (claim 3).
In each of the ribs, if the rib height is not uniform and has regions of different heights (Claim 4), the rib has a shape with excellent rigidity that maximizes the effect of the rib. can do.

According to the present invention, the proper rib arrangement can remarkably increase the rigidity of the container body, in particular, the rigidity in the torsional direction without using a reinforcing member, and a light and highly rigid pellicle storage container can be obtained at low cost. Can do.
The present invention is particularly effective when applied to a large pellicle storage container having a side exceeding 500 mm. However, the present invention is not limited to this size, and a pellicle storage container in which a resin sheet material is molded can be applied to a small one having a side of 200 mm. There is little problem of rigidity in the small size, but if the rigidity can be further increased by the structure, the sheet thickness can be reduced, and the weight can be reduced and the cost can be reduced as in the case of the large size.

Hereinafter, an embodiment of a pellicle storage container according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic view showing an example of a pellicle storage container (main body) according to the present invention, and FIG. 2 is a perspective view of the whole pellicle storage container. FIG. 5 shows a conventional container body having a rib structure, and FIG. 6 shows a deformation mode when the corner of the container body in FIG. 5 is lifted.

In the conventional pellicle storage container body 51 (FIG. 5), when an external force is applied in the twisting direction, for example, when a force is applied to lift the corner 57 upward, the container body 51 is bent at the diagonal line 54b. I will try.
At this time, the rib 53b originally needs to counter this torsional deformation, but since this rib is cut at the intersecting portion 59 by the intersecting rib 53a, sufficient resistance cannot be exhibited.
In addition, since the intersecting ribs 53a substantially coincide with the diagonal line 54b, the ribs themselves are most easily bent and become the base point of deformation as shown in FIG.
The present invention has been made in view of this point, and the inventor has made various types of prototypes and completed the present invention as a result of comparative studies.

In FIG. 2, a pellicle (not shown) is placed on the pellicle storage container main body 21 and covered with a lid 22. The lid 22 and the container main body 21 are sealed and fixed with an adhesive tape or the like (not shown), or fixed with a fastener such as a clip 23.
Although the container main body 21 and the lid body 22 can be manufactured by adhesion of a resin plate material, it is particularly preferable that the container main body 21 and the lid body 22 are manufactured by a vacuum forming method in terms of cleanliness and mass productivity.
The material of the lid and the container body can be appropriately selected from resins such as acrylic, ABS, and PVC, but it is preferable to use an antistatic material in order to reduce the adhesion of foreign matter due to charging. The lid is preferably transparent or semi-transparent for easy confirmation of the inside, and the container body is preferably black for easy confirmation of adhered foreign matter.

  The lid 22 is adapted to be fitted at the peripheral edge of the container body 21, and it is desirable that this gap be as narrow as possible in order to prevent foreign material from entering from the outside. And the container main body 21 is good to provide the some rib 13 which does not cross | intersect the diagonal 14 of the container main body outer shape, and cross | intersects another rib as shown in FIG. In the example of FIG. 1, four of these ribs 13 are provided. Of course, more ribs 13 may be provided, and the ribs 13 may be appropriately designed according to the size and outer shape of the container body.

  At this time, the angle a formed by the rib 13 with the diagonal line 14 is preferably 30 degrees or more, and more preferably as close to 90 degrees as possible. When an external force in the twisting direction acts on the container body, the maximum resistance is exerted when the angle that the rib crosses the diagonal is 90 degrees, and the effect is very small at 30 degrees or less, and the rib itself is a twisted bending line. It is easy to become.

FIG. 3 shows another embodiment of this rib arrangement. As in FIG. 1, ribs 33a, 33b, 33c, and 33d that cross the diagonal 35 are provided, but these ribs do not intersect with other ribs, but their ends are connected to the pellicle mounting base 32 and other ribs. Has been. If the connection is made at the end of the rib, the decrease in rigidity is hardly a problem.
In most cases, the ratio of the long side and the short side of the outer shape of the pellicle that is generally used is more suitable for such a design, which is more practical than the example of FIG.

Further, in the rib 33c in FIG. 3A, the height of the rib is not constant, as shown in FIG. It is particularly preferred to have it.
When the rib is torsionally deformed, as shown in FIGS. 4 and 6, the rib itself is likely to be a bending line of deformation. Thus, another surface (surface 42 generated by the stepped portion) is provided in the rib 41. Thus, the deformation amount of the rib itself can be reduced. In other words, it can be said that the surface 42 constitutes another reinforcing rib for reinforcing the rib 41.
And the width, height, arrangement, number, cross-sectional shape, etc. of these ribs may be appropriately designed according to the required rigidity and formability of the container body, and are not limited to the forms shown in these figures. is not.

Examples of the present invention will be described below, but the present invention is not limited thereto.
Using a sheet material of antistatic ABS (black), a pellicle storage container body 81 having the shape shown in FIG. 8 was manufactured by vacuum forming.
The size of the storage container main body 81 was 690 × 540 mm in outer shape, 30 mm in height, and the thickness of the sheet was 3 mm. The width of each rib is 20 mm. In addition to the ribs 83 that cross the diagonal, ribs 84 that are arranged substantially in parallel with the ribs 83 are provided in the center for further reinforcement.

The rib 83 is provided with a level difference equivalent to the perspective view of FIG. 4, and the height of the entire rib is 30 mm and the height of the level difference part is 20 mm.
The connection angle between the top surface and the step surface of the rib 83 is preferably a right angle, but is set to 60 degrees in consideration of formability. The rib 84 arranged in the central portion was made as low as 20 mm in order to prevent the pellicle film from shaking and contacting during transportation.
Then, in order to fix the pellicle to the container body, a fixing pin 85 made of PPS and a pin holder 86 made of ABS were attached with bolts (not shown) in accordance with the position of the pellicle to be housed. The fixing pin 85 is inserted and held in the pin holder 86, but has a structure that can be detached and attached by a lock mechanism.

The tip of the fixing pin 85 has a structure that can be inserted into a jig hole (not shown) provided on the side surface of the pellicle frame 87, and a ring-shaped viton on the contact surface with the pellicle frame 87 to prevent dust generation. A cushioning material (not shown) was attached.
Thereafter, pure water was washed cleanly in a clean room, and the pellicle 87 was actually mounted on the pellicle mounting table 82 of the completed pellicle storage container body 81 and fixed by the fixing pin 85.

And the container main body 81 was set | placed on the horizontal surface plate, and one corner part of the main body was lifted a little upwards. As a result, almost no torsional deformation was observed in the container main body 81, and the mounted pellicle remained firmly fixed on the surface of the container main body 81, and no particular change was observed.
Further, the fixing pin 85 was removed, and the jig hole in which the fixing pin 85 of the pellicle frame 87 was inserted was observed, but no particular contamination was observed. And the weight of this container main body was 1.38 kg.

[Comparative Example 1]
A pellicle storage container main body 91 having the shape shown in FIG. 9 was manufactured by a vacuum forming method in the same manner as in the above example, and a fixing pin 94 and a pin holder 95 were attached to the container main body 91. Thereafter, pure water was washed cleanly in a clean room, and the pellicle 96 was actually mounted on the pellicle mounting table 92 of the completed container body 91 and fixed by the fixing pins 94.
As an evaluation, similar to the above example, after the container body 91 was left horizontally, one corner portion of the container body was lifted slightly upward. Then, the container main body 91 was greatly bent along the rib 93 as shown in FIG.

  At this time, when the pellicle 96 mounted on the pellicle mounting table 92 was observed, the same bending as the deformation of the container body occurred in this direction (diagonal direction), and wrinkles occurred in a part of the pellicle film. Further, when the fixing pin 94 is pulled out from the jig hole of the pellicle 96, a large number of foreign objects generated by rubbing the pin strongly in the jig hole so as to be immediately recognized even under a fluorescent lamp. It was completely unacceptable.

[Comparative Example 2]
The pellicle storage container main body 71 having the shape shown in FIG. 7 was manufactured by the vacuum forming method in the same manner as in the above Example and Comparative Example 1, and the fixing pin 72 and the pin holder 73 were attached.
Further, on the outside of the container main body 71, rod-shaped reinforcing bodies 75 and 76 (width 40 mm × thickness 5 mm) of 6000 series aluminum alloy for reinforcement are combined in a Japanese character shape, a pin holder 73 made of ABS resin, reinforcement The body fixing tool 74 and the container main body 71 were firmly fastened with bolts (not shown) to complete the container main body.
Thereafter, pure water was washed cleanly in a clean room, and a pellicle 77 was actually mounted on the completed container body and fixed with fixing pins 72.

Then, in the same manner as in the above Example and Comparative Example 1, the pellicle storage container main body 71 was placed on a horizontal surface plate, and one corner portion of the main body was slightly lifted upward.
As a result, almost no torsional deformation was observed in the container body, and the mounted pellicle was also firmly fixed on the surface of the container body, and no particular defect was observed in appearance.
Then, the fixing pin 72 was pulled out from the jig hole of the pellicle 77 and observed with a halogen lamp in the dark room, but the vicinity of the jig hole remained clean.
However, the weight of the container body was 2.96 kg, which was twice or more that of the above example.

It is the schematic which shows an example of the rib structure of the pellicle storage container main body by this invention. It is the perspective view which showed the whole structure of the pellicle storage container by this invention. They are the top view (a) which shows another embodiment of the rib structure of the pellicle storage container main body by this invention, and the AA sectional view (b) of (a). It is the perspective view which showed the rib structure of the pellicle storage container main body by this invention. It is a top view which shows an example of the rib structure of the conventional pellicle storage container main body. It is an isometric view explanatory drawing explaining the deformation | transformation aspect in the conventional pellicle storage container main body. It is a top view which shows an example of the pellicle storage container main body using the conventional aluminum reinforcement body. It is a top view which shows one Example of the pellicle storage container main body by this invention. It is a top view which shows an example of the pellicle storage container main body using the conventional rib structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Pellicle storage container main body 12 Pellicle mounting base 13 Rib 14 Diagonal line a based on outline of container main body Angle formed by diagonal line crossed by rib 21 Pellicle storage container main body 22 Lid 23 Clip

31 Pellicle storage container main body 32 Pellicle placement bases 33a, 33b, 33c, 33d Rib 34 Rib 35 Diagonal line 41 based on outer shape of container main body Rib 42 Surface generated by stepped portion

51 Pellicle storage container main body 52 Pellicle mounting bases 53a, 53b Ribs 54a, 54b Diagonal lines 55, 56, 57, 58 based on container main body outer shape Corners 59 of container main body 59 Intersection of ribs

71 Pellicle storage container body 72 Pellicle fixing pin 73 Pin holder 74 Reinforcing body fixture 75 Aluminum alloy reinforcing body (short)
76 Long aluminum reinforcement
77 Pellicle

81 Pellicle storage container body 82 Pellicle mounting table 83 Rib 84 Rib 85 (for pellicle) fixing pin 86 Pin holder 87 Pellicle

91 Pellicle storage container main body 92 Pellicle mounting base 93 Rib 94 Pellicle fixing pin 95 Pin holder 96 Pellicle

Claims (2)

In a pellicle storage container comprising a container body manufactured by molding a resin sheet material on which a pellicle is placed, and a lid body that covers the pellicle and is fitted and locked at the periphery of the container body, the container body has at least 4 The ribs are arranged so as to form substantially rhombus-shaped sides in the cross section, and each of the ribs crosses the diagonal of the outer shape of the container main body at an angle of 30 degrees or more, and each of the ribs A pellicle storage container characterized by being connected to a pedestal on which another rib or pellicle is placed at an end portion without intersecting . 2. The pellicle storage container according to claim 1, wherein in each of the ribs, the height of the rib is not uniform but has regions having different heights.

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