JPH0626903Y2 - Moisture absorber and container for photomask or photomask substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention uses a hygroscopic material for storing and carrying a photomask or a photomask substrate used for semiconductor integrated circuits and the like. Regarding the container.

[Conventional technology]

Conventionally, it is known that a photomask or a photomask substrate is contaminated due to environmental changes such as temperature and vibration or changes over time.

Contamination with time is caused by the material of the photomask or the photomask substrate itself. That is, in the case of a glass containing alkali metal ions, water on the glass surface elutes alkali metal ions near the surface of the glass surface to produce various alkali metal ion salts.

Salt is generated by the residual ions when the photomask or the photomask substrate is washed.

Foreign matter adheres from others.

Etc. In either case, if there is water on the glass surface, it becomes dirty over time, and in particular, how the mask maker and the blanks maker reduce the dirt over time after cleaning and shipping the photomask or the photomask substrate, Furthermore, how to prevent dew condensation due to temperature change during transportation is a big problem.

As a technique for solving this, for example, Jikken Sho 63
No. 34273 is known. This will be described with reference to FIGS. 4 and 5. The container body 5 and the lid 6 are well-known containers for accommodating a photomask, and this container is generally made of a transparent or translucent synthetic resin so that the contents can be seen through. A wall-shaped convex portion 8 is vertically formed on the inner surface 7 of the container body 5 so that the photomask 1 can be stored in an upright state, and the bottom portion 9 has a shelf for supporting the bottom surface 10 of the photomask 1. Part 11 is being created.

On the other hand, a packing material 12 is attached above the lid 6, and by covering the container body 5 with the lid 6, the packing material 12 is pressed against the upper surface of the photomask 1 to prevent vibration during transportation. I am trying to protect the photo mask 1. The packing material 12 is made of a hygroscopic cotton cloth 13 having a multi-layered structure and having a cushioning property, and the cotton cloth 13 has water vapor permeability and does not easily generate and pass dust.
It is housed in the inside of the photomask 4, which prevents moisture from adhering to the surface of the photomask and improves the storage performance.

[Problems to be solved by the device]

However, in the conventional hygroscopic body of the photomask or the photomask substrate, the bag body 14 has water vapor permeability and does not easily generate and pass dust. However, in reality, these conditions are not satisfied. This is a trade-off, and there is a problem that if the moisture absorption effect is increased, dust easily passes, and if it is difficult to pass the dust, the hygroscopicity decreases. In particular, in order to prevent dew condensation caused by a temperature difference during transportation, it is necessary to have drying speed, durability of the drying effect, applicable humidity range, and adaptability to temperature changes. Has not been realized.

The present invention solves the above problems, and prevents the formation of dew condensation due to the temperature difference during transportation and the like, and is a photomask or a photomask substrate capable of sufficiently resisting vibration with less dust generation. An object is to provide a hygroscopic body and a container.

[Means for Solving the Problems]

Therefore, the moisture absorber of the photomask or the substrate for the photomask of the present invention is a hygroscopic body composed of a bag body and a desiccant sheet stacked and housed in the bag body, wherein the bag body is a microporous filter, The desiccant sheet is obtained by encapsulating silica gel in a foamed resin, and is characterized in that irregularities are formed on the surface thereof.
The bag body is a polypropylene sheet, and the foam resin is polyethylene. By disposing the hygroscopic body in the lid of the pattern plate storage container, it is possible to prevent dew condensation caused by a temperature difference during transportation and the like, and a photomask capable of generating little dust and sufficiently withstanding vibration. A container for a photomask substrate can be provided.

The microporous filter has a pore size of 0.
It is about 2 μm × 0.02 μm, and is not limited to the polypropylene sheet, and the foam resin is not limited to the polyethylene sheet.

[Action]

In the present invention, the bag body is a microporous filter, and has a water vapor transmission rate that is 2 to 10 times better than that of cellophane or non-woven fabric, and
It has very little dust passage. In addition, the desiccant sheet has a high moisture absorption rate, exhibits a long-term drying effect, and generates very little dust because the moisture absorbent is enclosed in the resin.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of a moisture absorber of a photomask or a photomask substrate of the present invention.

The hygroscopic body 21 of the photomask or the photomask substrate of the present invention comprises a bag body 22 and a desiccant sheet 23 that is housed in a laminated manner in the bag body 22. The hygroscopic body 21 is shown in FIG. It is arranged in the photomask storage container.

The bag 22 is a microporous filter and uses, for example, a polypropylene sheet (trade name: Duraguard, manufactured by Polyplastics). It has a water vapor permeability of 200 to 300 g / 100 cm ² · day, which is about 2 to 10 times better than that of cellophane and non-woven fabric, and has very little dust passage of 1 μ or more. Is.

The desiccant sheet 23 is a plate-shaped desiccant material having irregularities on its surface, and a large number of the desiccant sheets are stacked and stored in the bag body 22.
Since the surface has irregularities, it is excellent in cushioning property, and the thickness of the bag body 22 is adjusted by the number of the desiccant sheets 23 to be used for a pattern board storage container of various sizes. As shown in FIG. 2, the desiccant sheet 23 is obtained by encapsulating silica gel 25 in a foamed resin 26 to form a sheet. The desiccant sheet has a high moisture absorption rate, exhibits a long-term drying effect, and has a hygroscopic agent as a resin. Since it is sealed in, very little dust is generated. As the foamed resin, for example, a polyolefin resin, preferably polyethylene is used.

FIG. 3 shows the number of dusts generated from the hygroscopic body when the hygroscopic body of the present invention is housed in the container shown in FIG. 4 and vibrated.
By comparing the present invention A with the conventional example B, it can be seen that the moisture absorbent of the present invention is remarkably excellent.

[Effect of device]

As described above, according to the present invention, by forming unevenness on the surface of the desiccant sheet and stacking the unevenness, it is possible to obtain a hygroscopic body having excellent hygroscopicity and good cushioning property, and also laminating. Various sizes can be supported by adjusting the number of desiccant sheets. By storing this desiccant sheet in a bag that is a microporous filter, it is possible to prevent dew condensation caused by a temperature difference during transportation, generate less dust, and sufficiently withstand vibration. It produces a unique effect in the mask or photomask substrate and container.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of a moisture absorbent of a photomask or a photomask substrate of the present invention, FIG. 2 is an enlarged sectional view of a desiccant sheet, and FIG. FIG. 4 is a cross-sectional view of a conventional photomask container, in which the present invention and a conventional hygroscopic body are housed in a container and the number of dusts generated from the hygroscopic body is compared and explained when vibration is applied. FIG. 5 is a perspective view of a conventional hygroscopic body for a photomask. 21 ... Photomask or photomask substrate hygroscopic material, 22 ... Bag, 23 ... Drying material sheet, 25 ... Silica gel, 26 ... Foam resin.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-185313 (JP, A) Actual development Sho-60-46114 (JP, U) Actual public Sho-63-34273 (JP, Y2)

Claims (3)

[Scope of utility model registration request] 1. A hygroscopic body composed of a bag and a desiccant sheet which is stacked and housed in the bag, wherein the bag is a microporous filter, and the desiccant sheet encloses silica gel in a foamed resin. A hygroscopic body for a photomask or a photomask substrate, which is characterized in that the surface thereof has irregularities. 2. The bag body is a polypropylene sheet,
The hygroscopic body of the photomask or the photomask substrate according to claim 1, wherein the foamed resin is polyethylene. 3. A container for a photomask or a substrate for a photomask, characterized in that the hygroscopic body according to claim 1 or 2 is housed in a lid portion of the container.