KR20200140766A - Pellicle - Google Patents

Abstract

An objective of the present invention is to provide a pellicle having a suitable sectional shape of an adhesive layer so as not to cause loosening over a long period of time and to achieve an excellent appearance. The present invention provides the pellicle in which a pellicle film is attached to one frame surface of a pellicle frame with an adhesive layer, which is applied to the one frame surface of the pellicle frame, interposed there between, wherein a sectional shape of the adhesive layer opposite to the pellicle film is configured as a convex curve having a radius of curvature of R10 or more and R1000 or less. In addition, according to the present invention, the convex curve preferably has an approximately arcuate shape.

Description

PELLICLE

The present invention relates to a pellicle, such as for lithography, used as a dust film in manufacturing semiconductor devices, IC packages, printed circuit boards, liquid crystal displays, organic EL displays, and the like.

In the manufacture of semiconductors such as LSI and ultra-LSI or liquid crystal displays, a pattern is produced by irradiating a semiconductor wafer or a liquid crystal original plate with light, but the photomask or reticle used at this time (hereinafter, simply described as a photomask) is used. If dust adheres, the edge becomes uneven, and there is a problem that dimensions, quality, appearance, etc. are damaged, such as black contamination of the base.

For this reason, these operations are usually performed in a clean room. However, since it is difficult to always keep the photomask clean, exposure is performed after attaching a pellicle as a dust film on the surface of the photomask. In this case, since the foreign matter is not directly attached to the surface of the photomask but is attached to the pellicle, if the focus is placed on the pattern of the photomask during lithography, the foreign matter on the pellicle is irrelevant to the transfer.

In general, such a pellicle is composed of a pellicle frame and a pellicle film, but at the lower end of the pellicle frame constituting the pellicle, polybutene resin, polyvinyl acetate resin, acrylic resin, silicone resin, etc. are used to adhere the pellicle to the photomask. The formed adhesive layer and the release layer (separator) for the purpose of protecting the adhesive layer are formed.

On the other hand, although the pellicle film is adhered to the other side of the pellicle frame, the pellicle film is generally made of a material such as cellulose ester or fluororesin that transmits light well. For example, Patent Document 1 describes a method of dissolving a cellulose ester in an organic solvent, casting it on a smooth glass plate, forming a uniform thin film, and drying it to produce a pellicle film. In addition, Patent Document 2 describes a method of forming a cellulose acetate butyrate thin film, and Patent Document 3 describes a method of dissolving a fluorine-based polymer and coating it on a smooth flat plate using a spin coater to form a uniform pellicle film. Has been.

In addition, Patent Document 4 describes fixing this pellicle film to the pellicle frame with an adhesive made of a diorganopolysiloxane composition, and Patent Document 5 describes bonding the pellicle film to the pellicle frame with a silicone-based adhesive.

Japanese Patent Application Publication No. 58-219023 US patent 4861402 specification Japanese Patent Publication No. 63-27707 Japanese Patent No. 2945201 Japanese Patent No. 4185232

As described above, the pellicle film is applied and adhered to the pellicle frame by various adhesives, but at the time of this attachment, the shape of the surface of the adhesive layer has not been considered at all, and it is usually an unspecified shape or irregular shape.

Therefore, there is a problem that a part of the pellicle film to which the adhesive has been applied is not adhered or that a part of the pellicle film is not in contact. In addition, since such poor adhesion or poor contact causes a decrease in the adhesion area, it causes a decrease in the adhesion between the pellicle film and the pellicle frame, so that the pellicle film becomes loose, or in the worst case, the pellicle film peels off from the pellicle frame. Is occurring. In addition, when the shape of the adhesive layer is irregular and the bonding portion between the pellicle film and the pellicle frame has an irregular shape such as a spot shape or a wave shape, there is also a problem that the appearance becomes poor because bubbles are interposed therebetween.

Accordingly, the present invention has been made in view of such a problem, and it is an object of the present invention to provide a pellicle used for lithography or the like, which does not cause loosening over a long period of time by making it a cross-sectional shape of a suitable adhesive layer, and has excellent appearance.

In addition, the present inventors conducted a thorough study in order to achieve the above object, and found that a large difference in the adhesive force between the pellicle film and the pellicle frame or the appearance after bonding due to the difference in the cross-sectional shape of the adhesive layer, and proceeded further investigation. First, if the cross-sectional shape of the adhesive layer is composed of a convex curve with a radius of curvature of R10 mm or more and less than R1000 mm (hereinafter, the unit of curvature radius is omitted), it was found that problems such as poor adhesion were solved. It came to the invention.

That is, the present invention is a pellicle to which a pellicle film is attached via an adhesive layer applied to one frame surface of the pellicle frame, and the cross-sectional shape of the side opposite to the pellicle film of the adhesive layer is composed of a convex curve having a radius of curvature R10 or more and R1000 or less. It features.

In addition, the convex curve of the present invention is preferably substantially arcuate, and on the other frame surface of the pellicle frame, an adhesive layer for attaching the pellicle to the substrate and a release layer for protecting the adhesive layer can be formed. have.

According to the present invention, since there is no poor adhesion or poor contact, and since the adhesion area is large, sufficient adhesion between the pellicle film and the pellicle frame is obtained, the pellicle film adhered on the pellicle frame does not loosen over a long period of time, and is excellent in appearance. A pellicle can be provided.

1 is a longitudinal sectional view of a pellicle in which the cross-sectional shape of the adhesive layer of the present invention is arched.
2 is a plan view (top view) of the pellicle of FIG. 1.
3 is a longitudinal cross-sectional view of an arched pellicle in which the cross-sectional shape of the adhesive layer of the comparative example has a small radius of curvature.
4 is a plan view (top view) of the pellicle of FIG. 3.
5 is a longitudinal sectional view of a pellicle in which the cross-sectional shape of the adhesive layer of the comparative example is flat.
6 is a plan view (top view) of the pellicle of FIG. 5.

Hereinafter, one embodiment of the present invention will be described in detail, but the present invention is not limited thereto.

1 is a schematic cross-sectional view of a pellicle showing an embodiment of an adhesive layer shape according to the present invention, and FIG. 2 is a plan view (top view) thereof. In this pellicle, the pellicle film 11 has an adhesive layer on the top surface of the pellicle frame 12 of a normal square frame shape (rectangular frame shape or square frame shape) corresponding to the shape of the substrate (photomask or glass substrate portion thereof). 15), and on the other hand, an adhesive layer 13 for attaching the pellicle to the substrate is formed on the lower surface of the pellicle frame 12, and the adhesive layer 13 on the lower surface of the adhesive layer 13 A release layer (separator) 14 for protecting it is attached so as to be peelable.

In addition, the material of the pellicle film 11, the pellicle frame 12, the pressure-sensitive adhesive, the adhesive, and the separator 14 is not particularly limited, and a known material may be used.

When the pellicle film 11 is adhered to the pellicle frame 12 through the adhesive layer 15, the appearance of the pellicle film 11 and the pellicle frame 12 after adhesion due to the difference in cross-sectional shape of the adhesive layer 15 ), there is a large difference in the adhesive force, so in the present invention, the cross-sectional shape of the adhesive layer 15 is configured as a convex curve, and the radius of curvature of all portions of the convex curve is in the range of R10 or more and R1000 or less. will be. Further, the radius of curvature is more preferably R20 or more and R800 or less.

When this radius of curvature is less than R10, the curvature of the cross-section of the adhesive layer 15 becomes severe, and even if the pellicle film 11 is pressed against the pellicle frame 12 when attaching the pellicle film, the pellicle film 11 is formed on the entire adhesive surface. This is because the adhesion between the pellicle film 11 and the pellicle frame 12 decreases because the adhesion area is reduced due to the lack of contact.

In addition, when the radius of curvature exceeds R1000, the cross section of the adhesive layer 15 becomes a flat plate shape that is substantially horizontal (parallel to the adhesive surface of the pellicle frame), and thus the pellicle film 11 is attached according to the method of attaching the pellicle film 11. ) And the adhesive layer 15 because bubbles remain between the adhesive layer 15, the adhesive strength is lowered by the reduction of the adhesive area.

In the embodiment of the present invention, as shown in FIG. 1, the cross-sectional shape of the adhesive layer 15 is substantially arcuate, and the radius of curvature is R10 or more and R1000 or less. However, if such a substantially arcuate shape, the pellicle film 11 is formed. It is preferable because the adhesive can be adhered to the entire surface of the adhesive surface.

[Example]

<Example 1>

Hereinafter, examples will be described. In Example 1, a silicone adhesive X-40-3122 [Shin-Etsu Chemical Co., Ltd. product: product name] was diluted to a concentration of 10% with toluene and 2,2,4-trimethylpentane as an adhesive, and made of aluminum. The adhesive layer 15 was applied to the upper end of the pellicle frame 12 so that the cross-sectional shape of the adhesive layer 15 became a radius of curvature R360. Then, the pellicle frame 12 was heated to 130° C., and toluene and 2,2,4-trimethylpentane were volatilized to cure the adhesive.

On the other hand, in the case of manufacturing the pellicle film 11, Cytop CTX-S [manufactured by Asahi Glass Co., Ltd.: product name] was used as a material, and the concentration was used as a solvent CTsolv.180 [manufactured by Asahi Glass Co., Ltd.: product name]. Was diluted to 5%. Then, this solution was formed as a transparent film having a thickness of 1 µm on a surface-polished silicon substrate having a diameter of 200 mm and a thickness of 1.2 mm using a spin coater, and dried at 200°C for 15 minutes to form a thin film. This thin film was peeled off, and the pellicle film 11 was produced.

Next, the produced pellicle film 11 was attached to the adhesive layer 15 of the pellicle frame 12 prepared above. At this time, the first pellicle film 11 contacts the top of the arc shape of the adhesive layer 15 and starts to be bonded, and as the pellicle film 11 is pressed against the pellicle frame 12 (or the pellicle frame 12) As the side is pressed against the pellicle film 11] The bonding portion of the pellicle film 11 and the adhesive layer 15 widens around, and finally, the pellicle film ( 11) and the pellicle frame 12 could be bonded.

And, when the adhesive force between the pellicle film 11 and the pellicle frame 12 was measured, a value of 1.5 kN/cm was shown, but at this value, the pellicle film 11 side was broken, so the pellicle film 11 ) And the actual adhesion between the pellicle frame 12 can be said to be 1.5kN/cm or more.

<Example 2>

In Example 2, Cytop CTX-S [manufactured by Asahi Glass Co., Ltd.: product name] as an adhesive was diluted with NOVEC7300 [manufactured by Sumitomo 3M Co., Ltd.: product name] to a concentration of 6%, and a pellicle frame made of aluminum ( It applied so that the cross-sectional shape of the adhesive layer 15 might become the radius of curvature R100 on the upper end of 12). Thereafter, the pellicle frame 12 was heated to 130° C., and NOVEC7300 was volatilized to cure the adhesive. Other than this, it produced similarly to Example 1.

And, when the adhesive force between the pellicle film 11 and the pellicle frame 12 was measured, a value of 1.5 kN/cm was shown, but as in Example 1, the pellicle film 11 side was broken at this value. It can be said that the actual adhesive force between the film 11 and the pellicle frame 12 is 1.5 kN/cm or more.

<Example 3>

In Example 3, it was produced in the same manner as in Example 1 except that a silicone adhesive was applied to the pellicle frame 12 so that the cross-sectional shape of the adhesive layer 15 became a radius of curvature R10.

And, when the adhesive force between the pellicle film 11 and the pellicle frame 12 was measured, a value of 1.5 kN/cm was shown, but as in Example 1, the pellicle film 11 side was broken at this value. It can be said that the actual adhesive force between the film 11 and the pellicle frame 12 is 1.5 kN/cm or more.

<Example 4>

In Example 4, it was produced in the same manner as in Example 1 except that a silicone adhesive was applied to the pellicle frame 12 so that the cross-sectional shape of the adhesive layer 15 became a radius of curvature R1000.

And, when the adhesive force between the pellicle film 11 and the pellicle frame 12 was measured, a value of 1.5 kN/cm was shown, but as in Example 1, the pellicle film 11 side was broken at this value. It can be said that the actual adhesive force between the film 11 and the pellicle frame 12 is 1.5 kN/cm or more.

[Comparative Example]

<Comparative Example 1>

Next, a comparative example will be described. In this comparative example 1, it was produced in the same manner as in Example 1 except that a silicone pressure-sensitive adhesive was applied to the pellicle frame 12 so that the cross-sectional shape of the adhesive layer 15 became a radius of curvature R5 as shown in FIG. 3.

In addition, as a result of observing the bonding surface between the pellicle film 11 and the adhesive layer 15 of Comparative Example 1, the pellicle film 11 was formed by the adhesive layer 15, whether the curvature of the arc of the cross-section of the adhesive layer 15 was too small. It was not adhered to the entire surface of the adhered surface, and as shown in FIG. 4, the non-adhesive portion 17 remained, and adhesion was insufficient. Further, when the adhesive force between the pellicle film 11 and the pellicle frame 12 was measured, a value of 0.6 kN/cm was shown, but also in this case, peeling occurred between the pellicle film 11 and the pellicle frame 12. .

<Comparative Example 2>

In Comparative Example 2, as in Example 1, except that a silicone adhesive was applied to the pellicle frame 12 so that the cross-sectional shape of the adhesive layer 15 was parallel to the application surface of the adhesive of the pellicle frame 12 as shown in FIG. Made.

In addition, as a result of observing the adhesive surface of the pellicle film 11 and the adhesive layer 15 of Comparative Example 2, air bubbles remained between the pellicle film 11 and the adhesive layer 15, as shown in FIG. Part 17 was also left. In addition, when the adhesive force between the pellicle film 11 and the pellicle frame 12 was measured, a value of 0.7 kN/cm was shown, but in this case, peeling occurred between the pellicle film 11 and the pellicle frame 12. .

<Comparative Example 3>

In Comparative Example 3, it was produced in the same manner as in Example 1 except that a silicone pressure-sensitive adhesive was applied to the pellicle frame 12 so that the cross-sectional shape of the adhesive layer 15 became a radius of curvature R2000.

In addition, when the bonding surface of the pellicle film 11 and the adhesive layer 15 of Comparative Example 3 was observed, air bubbles remained between the pellicle film 11 and the adhesive layer 15. In addition, when the adhesive force between the pellicle film 11 and the pellicle frame 12 was measured, a value of 0.7 kN/cm was shown, but also in this case, peeling occurred between the pellicle film 11 and the pellicle frame 12. .

The results of Examples 1 to 4 and Comparative Examples 1 to 3 are summarized in Table 1 below.

As shown in the results of Table 1, if the cross-sectional shape of the adhesive layer is substantially arcuate, and the radius of curvature of all portions of the substantially arcuate shape is in the range of R10 or more and R1000 or less, the pellicle film 11 and the pellicle frame 12 ) Can be strongly bonded and the appearance of the bonded surface is also very good. On the other hand, even if the cross-sectional shape of the adhesive layer 15 is not arcuate or substantially arcuate, when the radius of curvature is out of the range of R10 or more and R1000 or less, it was confirmed that the adhesive strength is low and the appearance of the adhesive surface is also poor.

11: pellicle film 12: pellicle frame
13: adhesive layer 14: separator
15: adhesive layer 16: bonding portion of the pellicle film and the adhesive
17: non-adhesive portion of the pellicle film and the adhesive

Claims (7)

A pellicle in which a pellicle film is attached to one frame surface of the pellicle frame through an adhesive layer,
The cross-sectional shape of the adhesive layer on the side opposite to the pellicle film is composed of a convex curve having a radius of curvature of R20 mm or more and R1000 mm or less,
A pellicle, wherein the cross-sectional shape of the bonding portion between the pellicle film and the adhesive layer is a convex curve having a radius of curvature of R20 mm or more and R1000 mm or less. The method of claim 1,
A pellicle, characterized in that the convex curve is arcuate. The method according to claim 1 or 2,
A pellicle, characterized in that a pressure-sensitive adhesive layer for attaching the pellicle to a substrate and a release layer for protecting the pressure-sensitive adhesive layer are formed on the other frame surface of the pellicle frame. A photomask with a pellicle in which the pellicle according to claim 1 or 2 is attached to the photomask. An exposure method characterized by performing exposure using the photomask with a pellicle according to claim 4. A method for producing a semiconductor, characterized by performing exposure using the photomask with a pellicle according to claim 4. A method for manufacturing a liquid crystal display, wherein exposure is performed using the photomask with a pellicle according to claim 4.

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