JP3265137B2 - Pellicle and bonding method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pellicle, in particular, an LS.
I, substantially 500 used as a dust-repellent when manufacturing a semiconductor device such as an VLSI or a liquid crystal display panel.
The present invention relates to a pellicle in an exposure method using light of nm or less and a method for bonding the pellicle.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices such as LSIs and VLSIs or liquid crystal display panels, a semiconductor wafer or a liquid crystal master is irradiated with light to form a pattern. If dust adheres, the dust absorbs light or bends the light, so the transferred pattern will be deformed, the edges will be rough, and the white background will be stained black, However, there is a problem that the quality, appearance, and the like are impaired, and the performance and manufacturing yield of semiconductor devices and liquid crystal display panels are reduced.

[0003] For this reason, these operations are usually performed in a clean room. However, even in this clean room, it is difficult to keep the exposure master (lithography mask) clean at all times. A method of attaching a pellicle that allows the light for exposure to pass well is performed. In this case, the dust does not directly adhere to the surface of the exposure original, but adheres to the pellicle, so if the focus is set on the pattern of the exposure original during lithography,
The dust on the pellicle is not transferred, which leads to an improvement in the performance and manufacturing yield of semiconductor devices and liquid crystal display panels.

[0004] This pellicle structure is, for example, as shown in FIG. 1, in which a pellicle film 2 is provided on one side of a support frame 1.
Is provided by an adhesive 3, and an adhesive 4 is provided on one surface to be attached to the exposure master. This pellicle is inspected for foreign substances on the surface of the pellicle film before or after mounting on the exposure master, and if foreign substances are present on the pellicle film, the removal of foreign substances is attempted by air blowing. In this case, if the adhesive force between the pellicle film and the adhesive is not sufficient, there is a problem that the film is peeled off.

[0005] For this reason, a predetermined or more adhesive force is required between the pellicle film and the adhesive for the pellicle frame. The pellicle film has a thickness of several microns in order to obtain a high transmittance in the ultraviolet region. Since it is very thin as follows, it is often difficult to heat cure the adhesive, and therefore this may be an optical cure, but also in this case often it is not possible to obtain sufficient adhesive strength. In photocuring, the photopolymerization initiator is not completely consumed, which may be the cause of the low light resistance of the photocuring adhesive. This is because the pellicle film is thin, which increases the adhesive strength. There is also a problem that physical treatment such as roughening of the surface is difficult.

[0006]

On the other hand, with respect to this pellicle, the wavelength of light used during lithography has been shortened as the resolution of lithography has increased, and a KrF excimer laser (248 nm) has recently been used as a light source. Accordingly, as the material of the pellicle film, a fluorine-based amorphous resin having good light resistance even for shorter wavelengths has been used instead of the conventional cellulose-based film.

Further, as described above, in the conventional pellicle, there was a problem in the adhesive strength between the pellicle film and the pellicle frame adhesive. However, the pellicle film is made of an amorphous fluorine-based polymer. Then, there arises a problem that the problem of this and the adhesive strength between the pellicle frame adhesive and the pellicle frame adhesive further increases. For this purpose, a method has been proposed in which this type of pellicle film is modified with, for example, metallic sodium to increase the adhesive strength. However, this method involves a decrease in yield in the production of pellicles in which strict control of foreign substances is required. However, this surface modification is not always a good method. Accordingly, the object of the present invention is to address such disadvantages,
An object of the present invention is to provide a pellicle and a method for bonding the pellicle which solves the problems.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a pellicle which solves such disadvantages and problems and a method for bonding the pellicle. This bonding method heats a pellicle film made of a perfluoro amorphous polymer film. When bonding to a pellicle frame via an adhesive made of a silicone resin that cures with a pellicle, a pellicle film made of a perfluoro amorphous polymer film and a silicone resin cured by heating for the pellicle frame after heat curing The method is characterized in that the interface between the two layers comprising the agent layer is irradiated with ultraviolet rays to enhance the adhesive force between the two layers and to bond them. The two layers consisting of a pellicle film made of a perfluoro amorphous polymer film and an adhesive layer made of a silicone resin that is cured by heating for the pellicle frame have a difference in transmittance with respect to ultraviolet rays, and the ultraviolet rays are transmitted through ultraviolet rays. It is intended to irradiate from the layer with a high transmittance to the layer with a low ultraviolet transmittance, and it is preferable that the ultraviolet light used is of a short wavelength such that sufficient radicals are generated at the interface of the layer with a low ultraviolet transmittance. . The pellicle film made of a perfluoro amorphous polymer film has a transmittance of 70% or more for ultraviolet rays having a wavelength of 185 nm, and the adhesive made of a silicone resin which is cured by heating has a transmittance of 30% for ultraviolet rays having a wavelength of 185 nm. And the wavelength of the ultraviolet light to be irradiated is 200 n
m is more preferable. The pellicle of the present invention has a pellicle film made of a perfluoroamorphous polymer film having a transmittance of 70% or more for ultraviolet rays having a wavelength of 185 nm, and is cured by heating for bonding the pellicle frame to the pellicle frame. The adhesive made of a resin has a transmittance of 30% or less for ultraviolet rays having a wavelength of 185 nm, and is made of a silicone resin which is cured by heating for a pellicle frame after heating and curing ultraviolet rays having a wavelength of 200 nm or less through this pellicle film. The pellicle film is adhered to the pellicle frame by irradiating the adhesive layer.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted various studies on a method of bonding a pellicle film and an adhesive for a pellicle frame with a sufficient adhesive force. As a result, a pellicle film made of a perfluoro amorphous polymer film was obtained. And the adhesive made of a silicone resin that is cured by heating for the pellicle frame is selected so that there is a difference in the transmittance of ultraviolet rays. After the adhesive made of the silicone resin that is cured by heating is cured, the transmittance of ultraviolet rays is changed. When ultraviolet rays are irradiated from the higher side to the lower ultraviolet ray transmittance, the adhesive force at the interface with the lower ultraviolet ray transmittance is strengthened. I found that I can do that. The pellicle film as a perfluoro amorphous polymer film,
By irradiating ultraviolet rays having a wavelength of 200 nm or less using this method, it was confirmed that the pellicle film made of a fluoropolymer can be firmly adhered to the pellicle frame, and the present invention was completed. This will be described in more detail below.

[0010] The present invention relates to a pellicle and a method for bonding the pellicle.
The interface between two layers consisting of a pellicle film made of a perfluoro amorphous polymer film and an adhesive made of a silicone resin which is cured by heating for a pellicle frame after heat curing is irradiated with ultraviolet light to form an interface between the two layers. Strengthen the adhesive force between
This pellicle is characterized in that a pellicle film made of a perfluoro amorphous polymer film has a transmittance of 70% or more for ultraviolet light having a wavelength of 185 nm, and is used for a pellicle frame. Adhesive made of silicone resin that cures by heating has a wavelength of 185 nm.
The ultraviolet ray having a wavelength of 200 nm or less is bonded through a pellicle film made of a perfluoro amorphous polymer film after curing an adhesive made of a silicone resin which is cured by heating. The pellicle film made of a perfluoro amorphous polymer film is adhered to a pellicle frame by irradiating the agent layer, but according to this, the perfluoro amorphous polymer film Since the interface between the pellicle film and the adhesive made of a silicone resin that is cured by heating for the pellicle frame is strengthened by the ultraviolet irradiation, the pellicle film and the pellicle frame made of the perfluoroamorphous polymer film are separated. The advantage is given that it can be adhered with sufficient adhesion.

The method for bonding a pellicle film according to the present invention is a method for bonding two layers comprising a pellicle film made of a perfluoro amorphous polymer film and an adhesive made of a silicone resin which is cured by heating for a pellicle frame. After curing an adhesive made of a silicone resin that cures by heating, it is irradiated with ultraviolet light from the higher ultraviolet light transmittance to the lower ultraviolet light transmittance. These materials are used to enhance the adhesive force of the materials and to bond them. Generally, when ultraviolet light is applied to an organic material that absorbs in the ultraviolet region, the organic material absorbs the ultraviolet light and generates radicals. If this radical generation occurs inside the substance rather than on the surface of the substance, the radical propagates to the surroundings, and the generation, transfer, and recombination of the radical occur over a wide range. However, the present invention generates the radical at the interface between the two substances, The generation, transfer, and recombination of radicals over two substances enhances the adhesion between the two substances.

In this case, it is necessary to select a substance having a high transmittance to ultraviolet rays and a substance having a low transmittance to ultraviolet rays to be used as the two adherends. When irradiating ultraviolet rays from the high material side to the low UV transmittance material side, the UV light is not absorbed in the high UV transmittance material, so no radical is generated here, but the low UV transmittance material In the interior, ultraviolet rays are absorbed to generate radicals, and the bonding strength is strengthened at the interface between the two substances, so that these two substances are firmly bonded by the bonding strength. In addition, the ultraviolet rays used here must generate radicals when irradiated to a substance having a low transmittance of ultraviolet rays, and therefore have a short wavelength enough to generate radicals. Is required.

Since the pellicle produced by this method of bonding a pellicle film is used in a photolithography process in the manufacture of a semiconductor device, the pellicle used for the pellicle is ultraviolet (g-line 436 nm, i-line 365 nm, KrF excimer 248 nm). ) Is required. Although the pellicle film generally has no problem with light resistance, if the adhesive for the pellicle frame to be adhered to the pellicle film is an ordinary UV-curable adhesive, the ultraviolet light (light ) Has a wavelength of 250 to 450 nm, and this adhesive can be expected to have light resistance because, when it receives this ultraviolet ray (light) after curing, free radical decay proceeds due to residual photopolymerization initiator and the like. Therefore, it is unsatisfactory in terms of light resistance for bonding pellicles.

However, as the adhesive, a substance which cures by heating, has good light resistance to KrF excimer rays having a wavelength of 248 nm, and generates radicals when irradiated with ultraviolet rays having a wavelength of 200 nm or less, for example, silicone resin If a pellicle is adhered to the pellicle film according to the method of the present invention by using such an adhesive, a pellicle having a very high adhesive strength and a high light resistance to ultraviolet rays of 248 nm can be formed. .

Further, the pellicle according to the present invention comprises a pellicle film made of a perfluoro amorphous polymer film having a transmittance of ultraviolet rays having a wavelength of 185 nm of 70% or more as described above;
An adhesive for a pellicle frame having a transmittance of 30% or less of ultraviolet rays having a wavelength of 185 nm is used, and the adhesive layer is irradiated with ultraviolet rays having a wavelength of 200 nm or less through the pellicle to generate radicals at the interface, thereby strengthening the adhesion. The perfluoro amorphous polymer is an amorphous fluorinated polymer obtained by copolymerizing tetrafluoroethylene and a fluorinated monomer having a cyclic perfluoroether group. A formula commercially available under the trade name Teflon AF (trade name, manufactured by DuPont, USA)

Embedded image Or a formula commercially available under the trade name Cytop CTXS [trade name of Asahi Glass Co., Ltd.]

Embedded image (M and n are positive integers).

In the production of the pellicle film made of the fluorine-based organic material, the compound is prepared by using a fluorine-based solvent, for example, perfluoro (2-butyltetrahydrofuran) or perfluoro (2-propyltetrahydropyran). After dissolving to a concentration of 10%, a film may be formed by a solution caster method using a spin coater or a knife coater. This film may have a thickness of 0.5 to 10 μm, preferably 0.8 to 5 μm, and has a transmittance of 95% or more of ultraviolet rays from a practical viewpoint.

The pellicle film thus produced has good stability and does not yellow or crack during use. For example, g-line (wavelength 436 nm), i-line (wavelength 36
5 nm), excimer laser (KrF laser; wavelength 2)
48 nm), which shows excellent transparency even at a wavelength of 210 to 500 nm, and shows no deterioration in transparency even after long-term use. .

The adhesive used for curing the pellicle frame, which is cured by heating, has a wavelength of 1.
Since it is necessary that the transmittance of 85 nm ultraviolet rays is 30% or less and the ultraviolet rays having a wavelength of 20 nm or less generate radicals, this is, for example, an addition reaction type fluorine modification. Silicone adhesive X
70-346P [manufactured by Shin-Etsu Chemical Co., Ltd.] or the like may be used. If the adhesive is irradiated with ultraviolet rays having a wavelength of 200 nm or less through the pellicle film made of the above-mentioned perfluoro amorphous polymer film, the adhesive is exposed to the light. Since radicals are generated,
A pellicle in which the pellicle film is firmly adhered to the pellicle frame by the adhesive can be obtained.

[0019]

Next, examples of the present invention and comparative examples will be described. [Example] The following equation

Embedded image Was dissolved in the solvent CTsolv 180 [trade name of Asahi Glass Co., Ltd.] to prepare a solution having a concentration of 6.0%.

Next, this solution was prepared by adding a 200 mm diameter and a thickness of 3 mm.
A transparent film having a thickness of 0.84 μm was formed on a polished quartz substrate surface having a thickness of 0.8 mm using a spin coater.
A pellicle film was formed by drying for 15 minutes at, and the pellicle film had an ultraviolet transmittance of 95%. On the other hand, an addition-reaction-type fluorine-modified silicone adhesive X70 having an transmittance of 30% of ultraviolet rays having a wavelength of 185 nm as an adhesive is provided on an end surface of a pellicle frame formed of a 100 × 100 × 5 mm square aluminum frame which has been anodized.
-346P (described above) was applied to a thickness of 1 mm, and cured (vulcanized) by heating at 150 ° C for 10 minutes.

Next, 254 nm from the pellicle film,
The adhesive layer at a distance of 20 mm from the pellicle film is irradiated with ultraviolet light from a low-pressure mercury lamp (25 W × 4) having two wavelengths of 185 nm as main output wavelengths for 1 hour, and after irradiation, the pellicle film and the adhesive are irradiated. When the peeling was performed, the adhesive surface was not peeled and the film was broken, so that it was confirmed that the adhesive force between the pellicle film and the adhesive was sufficiently strong for practical use.

[Comparative Example] For comparison, the adhesion between the pellicle film and the adhesive in the example was bonded to the pellicle film before the adhesive was cured.
These were heated at 150 ° C. for 10 minutes to cure and adhere, and after the curing, the pellicle film and the adhesive were peeled off. As a result, the pellicle film was easily peeled from the adhesive layer.

[0023]

According to the method of the present invention, when a pellicle film, in particular, a pellicle film made of a perfluoro amorphous polymer film and an adhesive which is cured by heating for the pellicle frame are bonded, radicals are generated on the adhesive surface. Then, since an adhesive force is generated here, the pellicle film and the adhesive layer can be firmly adhered to each other without peeling.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a conventionally known example of a pellicle structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pellicle frame 2 ... Pellicle film 3 ... Adhesive 4 ... Adhesive

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-71134 (JP, A) JP-A-54-105774 (JP, A) JP-A-57-16083 (JP, A) 27641 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F 1/00-1/16

Claims (5)

(57) [Claims] Consisting 1. A consisting perfluoro amorphous polymer membrane Bae <br/> trickle film of silicone resin you cured by heating
Via adhesives to time to adhere to the pellicle frame, Pas
A pellicle film consisting of Furuoro amorphous polymer membrane, heated
Siri cured by heating for pellicle frame after curing
Irradiating ultraviolet radiation on the interface of the contact adhesive layer Toka Ranaru two layers of corn resin by enhancing the adhesion between the two layers,
A method for bonding a pellicle, which comprises bonding them. Wherein Resid be cured by heating for Bae <br/> trickle film and a pellicle frame made of perfluoro amorphous polymer membrane
The adhesives layer Toka Ranaru two layers of recone resin and some of the difference in the transmittance for ultraviolet rays, ultraviolet rays to claim 1 for irradiating a high layer side UV transmittance lower layer side UV transmittance The described pellicle bonding method. 3. The pellicle bonding method according to claim 1, wherein the ultraviolet light used has a short wavelength to generate sufficient radicals at the interface of the layer having a low ultraviolet transmittance. And at 4. A consisting perfluoro amorphous polymer membrane Bae <br/> trickle film transmittance of ultraviolet rays having a wavelength of 185nm is 70% or more, a silicone resin you cured by heating
UV transmittance at a wavelength of 185nm of contact adhesive is 30% bonding method of the pellicle according to any one of claims 1 to 3 wavelengths of ultraviolet to be irradiated is 200nm or less. 5. A perfluoro amorphous composed of a polymer film Bae <br/> trickle film transmittance of ultraviolet rays having a wavelength of 185nm is also a Ru der 70% city, for bonding and a pellicle frame which the contact <br/> adhesive comprising a silicone resin you cured as transmittance of ultraviolet rays having a wavelength of 185nm is 30% or less by heating, wavelength 200nm through the pellicle film
The following ultraviolet, heat cured, pellicle perfluoro non of the pellicle film was irradiated to the contact adhesive layer comprising a silicone resin you cured by heating the frame, characterized by comprising adhered to the pellicle frame Pellicle made of crystalline polymer film.