JP2000227653A - Pellicle for lithography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pellicle for lithography which causes no change in the standoff against a wide range of the sticking load of the pellicle and which causes no sticking failure by air passage. SOLUTION: This pellicle has at least a pellicle film 1, a pellicle frame 2 to adhere the pellicle film, and an adhesive layer 4 on the lower end face of the pellicle frame to fix the frame to the substrate 3 for exposure. The adhesive layer 4 has a two-layer structure of an elastic material 5 having self- adhering property and an adhesive 6. In this method, the elastic material 5 is a silicone rubber which is hardened at room temp., and the adhesive 6 is a silicone adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses light having a wavelength of substantially 500 nm or less, which is used as a pellicle for lithography, in particular, for removing foreign matter when manufacturing semiconductor devices such as LSIs and super LSIs or liquid crystal display panels. The present invention relates to a pellicle for lithography in an exposure method.

[0002]

2. Description of the Related Art In manufacturing semiconductor devices such as LSIs and VLSIs, or liquid crystal display panels, etc., when irradiating a semiconductor wafer or a liquid crystal original plate with light to perform patterning, foreign substances adhere to an exposure substrate. Then, the foreign matter absorbs or bends the light, causing an abnormality in the transferred pattern, resulting in a problem that the performance and the production yield of the semiconductor device, the liquid crystal display panel and the like are lowered.

In order to prevent this, the exposure operation is usually performed in a clean room. However, even in this clean room, it is difficult to keep the exposure substrate completely clean. A method of attaching a pellicle has been performed.

In this case, the foreign matter does not directly adhere to the surface of the exposure substrate but adheres to the pellicle film. Therefore, if the focus is adjusted on the pattern of the exposure substrate at the time of exposure, the foreign matter on the pellicle film is reduced. Be independent of transcription.

This pellicle is usually formed by coating a transparent pellicle film made of nitrocellulose, cellulose acetate or the like which allows light to pass through well, and coating a good solvent of the pellicle film on a pellicle frame made of aluminum, stainless steel, polyethylene or the like. After adhering to each other, they are air-dried and adhered (see JP-A-58-219023) or adhered with an adhesive such as an acrylic resin or an epoxy resin (US Pat. No. 4,861,402).
JP-A-63-27707), an adhesive layer for mounting on an exposure substrate below the pellicle frame, and a release layer (liner) for protecting the adhesive layer. ing.

The adhesive layer in contact with the lithographic pellicle and the substrate for exposure has elasticity so as not to damage the substrate for exposure at the time of bonding, and further has a gap between the adhesive layer and the substrate for exposure (hereinafter referred to as “air path”). A material that causes some plastic deformation is used so as not to cause the above.

As described above, in order to give elasticity to the adhesive layer, a double-sided tape using a sponge-like member as a part of the material has conventionally been used. However, mainly due to the problem of dust generation,
At present, an adhesive made of a polybutene resin, a polyvinyl acetate resin, an acrylic resin, a silicone resin, or the like is directly applied to the lower surface of the pellicle frame and molded, and is mainly used.

[0008]

However, when the pellicle for lithography is attached to the substrate for exposure, the pellicle can be attached manually or using an automatic apparatus.
The optimum hardness of the adhesive layer differs depending on the bonding load and the bonding conditions, and the problem is that the best bonding can be obtained only in a very narrow range of bonding conditions.

More specifically, when the bonding load is larger than the optimum condition, the distance from the pattern surface of the designed lithography pellicle on the exposure substrate to the pellicle film (hereinafter referred to as "stand-off"). ), Which causes a problem that the inspection of foreign substances on the pellicle film cannot be performed accurately. On the other hand, when the bonding load is small, the parallelism between the lithography pellicle and the exposure substrate at the time of bonding may not be maintained, and there is a problem that an air path is easily generated.

[0010] On the other hand, if a uniform load is applied to the entire surface of the pellicle frame, good bonding can be performed. However, if the pressing jig is inclined, the bonding load becomes non-uniform. Problems such as distribution and air paths occur.

Further, when the hardness of the adhesive layer is reduced to prevent the occurrence of an air path, the change in the stand-off due to the change in the sticking load becomes remarkable. In this case, if the sticking load is too large, the pellicle frame will stick. The layers may be torn apart and come into direct contact with the exposure substrate, causing damage to the exposure substrate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and there is no change in the stand-off with respect to a wide range of a lithographic pellicle application load, and furthermore, a lithography system which does not cause an adhesion failure due to an air path. The main purpose is to provide a pellicle for use.

[0013]

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems, and the invention described in claim 1 of the present invention provides at least a pellicle film and a pellicle frame for bonding the pellicle film. And a lithographic pellicle having an adhesive layer for fixing to an exposure substrate located at the lower end surface of the pellicle frame, wherein the adhesive layer has a two-layer structure of an elastic body having self-adhesiveness and an adhesive. It is a pellicle for lithography, which is a feature.

As described above, if the adhesive layer has a two-layer structure of the self-adhesive elastic body and the pressure-sensitive adhesive, the change of the stand-off against the pellicle sticking load over a wide range can be suppressed and the air path can be reduced. Adhering defects can be avoided. Furthermore, the presence of the elastic body does not damage the exposure substrate even if the bonding load is too large.

In this case, as described in claim 2, the elastic body having self-adhesiveness can be a room-temperature-curable silicone rubber, and the adhesive can be a silicone adhesive.

As described above, if the elastic body having self-adhesive properties is a room-temperature-curable silicone rubber and the adhesive layer has a double structure in which the pressure-sensitive adhesive is a silicone pressure-sensitive adhesive, it can be applied to a wide range of application loads. On the other hand, a constant stand-off can be maintained, and the sticking failure due to the air path can be reliably avoided.

Further, as described in the third aspect, it is desirable that the two-layer structure has a structure in which an elastic body having self-adhesive property is provided on the pellicle frame side and an adhesive is provided on the exposure substrate side.

As described above, if the two-layer structure of the adhesive layer has a structure in which the elastic body having self-adhesive property is provided on the pellicle frame side and the adhesive is provided on the exposure substrate side, the bonding load is too large. This can also reliably prevent the exposure substrate from being damaged. In addition, the pellicle frame is securely adhered and fixed by an elastic body having self-adhesive properties, and the exposure substrate is firmly adhered by an adhesive, and the elastic body and the adhesive are firmly bonded, so that the stand-off Is stabilized, and the air path can be avoided.

Further, as described in claim 4 of the present invention, the two-layer structure of the adhesive layer can be a structure in which an elastic body is covered with an adhesive.

As described above, if the two-layer structure of the adhesive layer has a structure in which the elastic body is covered with the adhesive, the elastic body and the adhesive are firmly bonded, so that the stand-off can be stabilized. In addition to this, it is possible not only to avoid the sticking failure due to the air path, but also to prevent the exposure substrate from being damaged because the soft adhesive comes into contact with the exposure substrate.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments. Here, FIG. 1 is an enlarged sectional view showing an example of a pellicle for lithography in the present invention.

As shown in FIG. 1, the pellicle for lithography of the present invention has at least a pellicle film 1, a pellicle frame 2 and an adhesive layer 4. In addition, the pellicle frame 2 is bonded to the pellicle frame 2 via a self-adhesive elastic body 5 and an adhesive 6 constituting the adhesive layer 4.

The pellicle film 1 is made of a material that transmits light well, for example, conventionally known nitrocellulose, cellulose acetate and the like, and the pellicle frame 2 is similarly made of conventionally known aluminum, stainless steel, polyethylene and the like. Further, the exposure substrate 3 may be any substrate such as a reticle, a photomask, and the like, as long as the substrate is irradiated with light and subjected to lithography, without being limited to its name.

The elastic body 5 having self-adhesiveness, which is one of the substrates constituting the adhesive layer 4 having a two-layer structure, which is a feature of the present invention, is formed by a hydrolyzable group curable by moisture, ultraviolet rays, or the like. An elastomer having a radical polymerizable group such as a photo-curable vinyl group, acrylic group, and (meth) acryl group can be used.

Examples of the elastomer include silicone, polysulfide, polyurethane, acrylurethane, polyvinyl chloride, chloroprene, chlorosulfonated polyethylene, ethylene propylene, and asphalt-impregnated polyurethane.
In addition, two or more kinds of the above resins may be appropriately mixed and used.

Of these, silicone-based, particularly room-temperature-curable silicone rubber is preferably used in consideration of handleability, light resistance, and the like. Specifically, as a reactive group subjected to room-temperature curing, a methylethylketoxime group or an acetoxy group is used. It is preferable to use a room-temperature-curable silicone rubber having an alkoxy group, an isopropenoxy group, an amino group or an amide group. Among these examples,
It is further desirable to select a room temperature-curable silicone rubber having an alkoxy or isopropenoxy group suitable for electronic use.

There are so-called one-part and two-part types of room-temperature-curable silicone rubbers. It is desirable to use a one-part room-temperature-curable silicone rubber which is effective as an elastic adhesive.

Next, the pressure-sensitive adhesive 6, which is the other base material constituting the two-layer structure of the adhesive layer 4, is a hydrolyzable material which can firmly adhere not only to a base material such as a substrate for exposure, but also to the elastic body 5. An adhesive having a group or a radical polymerizable group is desirable.

Examples of the pressure-sensitive adhesive include various ones such as silicone resin, acrylic resin, natural rubber, and synthetic rubber. Among them, the silicone resin-based adhesive has good affinity with the room temperature-curable silicone rubber. Therefore, it is desirable.

As described above, the feature of the present invention is that the adhesive layer 4 has a two-layer structure as described above, and the characteristics of the two base materials constituting the two-layer structure are different. That is, the two-layer structure was made up of the elastic body 5 having self-adhesiveness and the soft and sticky adhesive 6.

The positional relationship between the elastic body 5 and the adhesive 6 constituting the two-layer structure is such that the elastic body 5 having self-adhesive property is arranged on the pellicle frame 2 side, and the adhesive 6 is arranged on the exposure substrate 3 side. It is preferable to adopt a structure that does.

According to such a structure, the presence of the elastic body having high hardness can suppress the change of the stand-off with respect to the pellicle bonding load over a wide range. Furthermore, due to the presence of the soft pressure-sensitive adhesive, it is possible to avoid poor bonding due to the air path, and to avoid damage to the exposure substrate 3 even when the bonding load is too large.

FIG. 2 shows a specific form of the two-layer structure.
A structure in which an elastic body 5 having self-adhesive properties is adhered to the entire lower end of the pellicle frame 2 as shown in (A), and an adhesive 6 is applied to the entire surface of the elastic body 5, as shown in (B). After covering the entire lower end of the pellicle frame 2 with an elastic body 5 having self-adhesive properties, the entire elastic body 5 is covered with an adhesive 6, and a part of the lower end face of the pellicle frame 2 is self-adhesive as shown in FIG. There is a structure in which after covering with an elastic body 5 having

In the structure shown in FIG. 2C, the elastic body 5 and the adhesive 6 are compared with each other, and a substrate made of a material having higher light resistance is arranged inside the pellicle. It is desirable to do.

According to the method shown in FIGS. 2A, 2B or 2C, the whole or a part of the lower end of the pellicle frame 2 is covered with a self-adhesive elastic body 5 to stabilize the stand-off. And the distribution is constant. Further, since the adhesive 6 located on the side of the exposure substrate 3 is easily crushed even with a small attachment load, it is possible to prevent the occurrence of an air path.

[0036]

The present invention will be described below with reference to examples and comparative examples.

(Embodiment) The height is 5.0 mm and the outer circumference is 12 mm.
An aluminum pellicle frame having a 0 mm square and an inner circumference of 114 mm square and having an alumite-treated surface was prepared. Room temperature curable silicone rubber, KE3497
(Shin-Etsu Chemical Co., Ltd.) was applied so as to have a semicircular cross section having a maximum thickness of 0.5 mm, and then left at room temperature for 6 hours to cure.

Next, a silicone adhesive, X-40-30
92 (manufactured by Shin-Etsu Chemical Co., Ltd.) is applied over the room-temperature-curable silicone rubber layer so as to cover the room-temperature-curable silicone rubber layer. And dried by heating at 120 ° C. for 10 minutes.

With respect to the pellicle frame thus manufactured,
It was pasted on a glass substrate. No air path was observed between the bonded glass substrate and the adhesive layer. As the sticking condition, the sticking time was kept constant for 3 minutes, and the change of the stand-off in a state where the sticking load was changed was measured for 10 minutes and one week after the sticking was completed. The results are shown in Table 1. As is clear from the results, a certain standoff was obtained when the applied load exceeded 5 kg.

[0040]

[Table 1]

COMPARATIVE EXAMPLE A silicone adhesive, X-40-3092 (described above), having a maximum thickness of 1.0 was applied over the entire lower end surface of the same aluminum pellicle frame used in Example 1.
It was applied so as to have a semicircular cross section of 1 mm and heated and dried at 120 ° C. for 10 minutes to form an adhesive layer.

With respect to the pellicle frame thus manufactured,
It was pasted on a glass substrate. No air path was observed between the bonded glass substrate and the adhesive layer. The sticking conditions were the same as those in the example, and the stand-off was measured. The results are shown in Table 2. As is clear from the results, a change in the stand-off was observed under any condition of the application load.

[0043]

[Table 2]

As is clear from the above results, if the adhesive layer has a two-layer structure composed of an elastic body having self-adhesive properties and a pressure-sensitive adhesive, there is no change in the stand-off with respect to the application load, and the time-lapse is further improved. No fluctuation due to

The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the claims of the present invention. Within the technical scope of

For example, in the present invention, the case where a silicone resin and a silicone pressure sensitive adhesive are used as the two base materials for forming the adhesive layer has been specifically described. I do not care.

[0047]

According to the present invention, the adhesive layer of the pellicle for lithography has a two-layer structure and the two materials constituting the two-layer structure have different characteristics. It is possible to maintain a constant stand-off, and it is possible to eliminate sticking failure due to an air path.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing an example of a pellicle for lithography of the present invention.

FIG. 2 is a sectional view of an adhesive layer for adhering a pellicle frame, which is a component of the pellicle for lithography of the present invention, to a substrate for exposure. (A) is an adhesive layer in which a self-adhesive elastic body is adhered to the entire lower end of the pellicle frame, and an adhesive is applied to the entire surface of the elastic body. (B) is an adhesive layer in which the entire lower end of the pellicle frame is covered with an elastic body having self-adhesive properties, and the entire surface of the elastic body is covered with an adhesive.
(C) is an adhesive layer in which a part of the lower end surface of the pellicle frame is covered with an elastic body having self-adhesive properties, and the entire surface of the elastic body is covered with an adhesive.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pellicle film, 2 ... Pellicle frame, 3 ... Exposure substrate, 4 ... Adhesive layer, 5 ... Elastic body having self-adhesive properties, 6 ... Adhesive.

Claims (4)

[Claims] 1. A lithographic pellicle having at least a pellicle film, a pellicle frame for bonding the pellicle film, and an adhesive layer for fixing to a substrate for exposure located at a lower end surface of the pellicle frame, wherein the adhesive layer is A pellicle for lithography, which has a two-layer structure of an elastic body having self-adhesiveness and an adhesive. 2. The pellicle for lithography according to claim 1, wherein the elastic body having self-adhesive properties is a room-temperature-curable silicone rubber, and the adhesive is a silicone adhesive. 3. The method according to claim 1, wherein the two-layer structure has a structure in which an elastic body having self-adhesive property is provided on a pellicle frame side and an adhesive is provided on an exposure substrate side. The pellicle for lithography according to the above. 4. The pellicle for lithography according to claim 1, wherein the two-layer structure is a structure in which the elastic body is covered with an adhesive.