JP2000305252A - Method for peeling pellicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To peel a pellicle from a reticle while preventing the contamination of the reticle and reducing effect on the reticle by heating an adhesive layer between the pellicle and the reticle. SOLUTION: Then a pellicle is peeled from a reticle, an adhesive layer between the pellicle and the reticle is heated to 40-150 deg.C, preferably 50-120 deg.C. In the case of <40 deg.C, the adhesive is not thoroughly softened and smooth peeling is difficult. In the case of >150 deg.C, the adhesive deteriorates thermally and residue on the surface of the reticle increases. The adhesive layer may be heated by a method using the radiant heat of a high temperature body such as a hot air drier or an IR lamp, a heat conduction method by contact with a high temperature body such as a hot plate or an indirect heating method in which only the frame is heated by high-frequency induction heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for separating a pellicle from a reticle used when manufacturing a semiconductor device such as an LSI or a super LSI or a liquid crystal display panel.

[0002]

2. Description of the Related Art Conventionally, photomasks used in manufacturing semiconductor devices such as LSIs and VLSIs and liquid crystal display panels have been manufactured by using a reticle as an original plate and sequentially exposing a photorepeater to light. An enlarged mask used in a wafer stepper is also called a reticle.

Since the reticle is an enlarged mask, the dimensional accuracy, position accuracy, and the presence / absence of a defect tend to be slightly tolerated. However, the reticle has a defect common to all successively exposed chips. And in recent years,
As patterns have become finer and more precise, performance that is equal to or higher than that of a full-scale photomask has been required.

For this reason, hitherto, a hard blank has been generally used for a reticle substrate. Further, the reticle is manufactured by a pattern generator having a long exposure time, so that the manufacturing cost is high. Further, since the defect is corrected by a laser repair machine or partial deposition, the cost is further increased. Therefore, in order to protect the perfect reticle pattern, a transparent thin film (a thin film made of an organic compound such as nitrocellulose,
(Called a pellicle) and sealing. According to this method, even if foreign matter adheres during use,
The foreign matter is out of focus because it is on the thin film of the pellicle, and it is possible to prevent a defect from occurring in the resist.

[0005] The pellicle is replaced when a certain number or more of foreign matter or a foreign matter of a certain size or more adheres to the film or when the film is broken. However, if the pressure-sensitive adhesive that adheres the pellicle to the reticle has a strong adhesive strength, or if the pressure-sensitive adhesive is brittle, there is a problem that traces of the pellicle removed and a part of the pressure-sensitive adhesive remain on the reticle surface. Therefore,
At present, after removing unnecessary pellicles by a stripping method using a solvent, the adhesive residue of these adhesives is removed by a method such as acid cleaning of the reticle surface.

[0006]

At present, when an unnecessary pellicle is peeled off from the reticle as described above, a solvent such as IPA (isopropyl alcohol) is dropped, and the pressure-sensitive adhesive is swollen to lower the peeling strength and peel off. Or a method of mechanically peeling off unnecessary pellicles. However, when the reticle is peeled off using a solvent, secondary contamination due to the solvent occurs on the reticle surface, and the burden on the subsequent reticle cleaning step increases. In addition, the method of mechanically peeling off unnecessary pellicles not only places a burden on the reticle but also exerts an excessive force on the adhesive when peeling off, and foreign matter is generated from the adhesive layer at the moment of peeling. The possibility of contaminating the reticle is very high. Naturally, a contaminated reticle increases the burden on the cleaning process and at the same time carries the risk of mechanical damage on the reticle. If there is only a small amount of glue residue on the reticle surface after the unnecessary pellicle has been peeled off, only the portion where the adhesive has been applied is omitted. be able to. This leads to a dramatic streamlining of the process. In view of the above circumstances, the inventors have conducted various studies on a pellicle peeling method for solving these problems, and as a result, have reached the present invention.

[0007]

According to the present invention, there is provided a pellicle peeling method for solving the above-mentioned problems, wherein the pellicle is peeled off from the reticle while the adhesive layer between the pellicle and the reticle is heated. This is a pellicle peeling method characterized in that it is performed. Generally, the pressure-sensitive adhesive has a property of softening as the temperature increases. Therefore, when the pellicle is peeled off in a heated state as in the present invention, the pellicle can be relatively smoothly peeled off from the reticle because the pressure-sensitive adhesive is softer than at room temperature. Further, by increasing the heating temperature, this phenomenon becomes more remarkable and the film can be easily separated.

[0008] The present invention relates to a pellicle peeling method, in which a pellicle is peeled from a reticle by heating a pressure-sensitive adhesive layer between the pellicle and the reticle without using a solvent, thereby preventing reticle contamination. Such a burden can be greatly reduced, and peeling can be performed.
The present invention is a pellicle peeling method for suppressing contamination of the reticle surface from the pressure-sensitive adhesive layer at the time of pellicle peeling, preventing an expensive reticle from being excessively burdened, and preventing the risk of reticle breakage.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. As a method of heating the pressure-sensitive adhesive layer in the present invention, a hot air dryer, an infrared lamp, a method using radiant heat of a high-temperature body such as a hot plate, a method using heat conduction brought into contact with a high-temperature body such as a hot plate, and high-frequency induction heating are used. A method in which an induced current is passed through the frame without contacting the pressure-sensitive adhesive layer, and only the frame is efficiently heated and the pressure-sensitive adhesive layer is indirectly heated is possible. In the method of the present invention, when the pellicle is peeled from the reticle, the pressure-sensitive adhesive layer between the pellicle and the reticle is peeled while being heated, and the heating temperature of the pressure-sensitive adhesive layer may be 40 ° C to 150 ° C. Necessary, preferably 50-120 ° C. If the heating temperature is lower than 40 ° C., the pressure-sensitive adhesive is not sufficiently softened, so that smooth peeling becomes difficult. If the temperature is higher than 150 ° C., adhesive residue on the reticle surface increases due to thermal deterioration of the pressure-sensitive adhesive.

The method of peeling the pellicle from the reticle according to the present invention is described in detail in Examples. However, briefly described below, the pressure-sensitive adhesive layer between the pellicle and the reticle is formed by radiant heat of the high-temperature body and high-temperature body. The pellicle is heated to 40 ° C. to 150 ° C. by heat conduction, high-frequency induction heating or the like to be brought into contact, and then the pellicle is peeled off by slowly pulling it up from the long side or the short side.

In the present invention, the pressure-sensitive adhesive for adhering the pellicle to the surface of the reticle may be generally used in such a case.
Examples of the adhesive include silicone, nitrile rubber, SBR, chloroprene rubber, and natural rubber. In the present invention, the adhesive used on the upper end surface of the frame when the pellicle is adhered to the surface of the reticle may be generally used in such a case, and examples thereof include epoxy, silicone, fluorine, and fluorine. Silicone-based,
An adhesive such as a cyanoacrylate-based adhesive may be used.

Of course, the pellicle peeling method of the present invention is applicable to commonly used pellicles and reticles. A commonly used pellicle is a thin film having a high light transmittance of about 0.5 to 5 μm, which is adhered to a frame made of an aluminum alloy using the above-mentioned adhesive or adhesive without wrinkles or sagging. The reticle is a pattern in which a metal such as chrome is used for a synthetic quartz surface polished substrate.

[0013]

Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention.

(Example 1) The surface was subjected to alumite treatment.
An aluminum frame with a height of 6.3 mm, an outer circumference of 150 mm × 120 mm, a thickness of 2 mm, and a 0.5 mm φ through hole in the center of one side was prepared. As shown in FIG. 1, a silicone adhesive, KR-120 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) (4) was applied to the lower end surface so as to form a 0.6 mm-thick bale and heated to 120 ° C. , 30
And dried. Further, Cytop CT69 (trade name, manufactured by Asahi Glass Co., Ltd.) is used as an adhesive (3) on the upper end surface of the frame (5).
Was applied to a thickness of 0.1 mm. Separately produced polymer of amorphous perfluorobutenyl vinyl ether
A 1.62 μm-thick pellicle film (1) made of CYTOP CTX-S [trade name of Asahi Glass Co., Ltd.] was adhered to the upper end surface of the frame (5) to produce a pellicle frame. The lower end face coated with the silicone adhesive was placed on the reticle (2), and a load of 20 kg was adhered to the reticle (2) on the pellicle film (1) for 1 minute. In the pellicle manufactured as described above, even when the pellicle frame was adhered to the reticle (2) as described above, no gap such as an air path was observed between the reticle and the pellicle frame.
This pellicle is adhered on a reticle,
After standing for months, the pellicle was peeled off from the reticle by the following method. The reticle to which the pellicle was adhered was heated by a high-frequency induction heating device so that the temperature of the pressure-sensitive adhesive layer became 80 ° C. Next, the pellicle frame was slowly separated from the reticle from the long side. After peeling, the particles on the reticle surface and the glue residue of the adhesive were observed by a light-condensing test. As a result, nothing was observed except for the slight glue residue of the original adhesive portion.

(Example 2) The pellicle to which the pellicle obtained in Example 1 was adhered was allowed to stand at room temperature for one month, and then the pellicle was peeled off from the reticle by the following method. The reticle to which the pellicle was adhered was heated on a hot plate such that the temperature of the pressure-sensitive adhesive layer became 50 ° C. Next, the frame was slowly separated from the reticle from the long side. After peeling, the particles on the reticle surface and the glue residue of the adhesive were observed by a light-condensing test, and nothing was observed except for a slight glue residue of the original adhesive portion.

(Example 3) The pellicle to which the pellicle obtained in Example 1 was adhered was left at room temperature for one month, and then peeled off from the reticle by the following method. The reticle to which the pellicle was adhered was heated on a hot plate so that the temperature of the pressure-sensitive adhesive layer became 120 ° C. Next, the pellicle frame was slowly separated from the reticle from the long side. Compared to Example 2, the film could be more smoothly peeled. After peeling, the particles on the reticle surface and the glue residue of the adhesive were observed by a light-condensing test, and nothing was observed except for a slight glue residue of the original adhesive portion.

(Comparative Example 1) The pellicle to which the pellicle obtained in Example 1 was adhered was allowed to stand at room temperature for one month, and then the adhered pellicle was separated from the reticle by the following method. The pellicle frame was slowly peeled from the reticle from the long side while keeping the pellicle frame at room temperature. Peeling required a great deal of force, and there was a loud snapping sound when peeling. After peeling, the particles on the reticle surface and the glue residue of the adhesive were observed by a light-concentration test, and there was only a slight glue residue on the original adhesive part, but ten peeled pieces were found in the pattern area. Was observed.

Comparative Example 2 The pellicle to which the pellicle obtained in Example 1 was adhered was left at room temperature for one month, and then peeled off from the reticle by the following method. Around 5 cc of IPA (isopropyl alcohol) was dropped along the outer periphery of the pellicle frame and left for 5 minutes. Next, the pellicle frame was slowly peeled from the reticle from the long side while the room temperature was maintained. Peeling could be performed smoothly. After peeling, the particles on the reticle surface and the glue residue of the adhesive were observed by a light-concentration test. As a result, not only was there much glue residue on the original adhesive portion, but also scattering traces of the glue on the periphery were observed.

[0019]

According to the present invention, the pellicle can be easily peeled off from the reticle by heating the pressure-sensitive adhesive layer between the pellicle and the reticle even when a pressure-sensitive adhesive having a high adhesive strength is used. Without damaging the reticle, and minimizing the contamination of the reticle by the adhesive, which makes it possible to omit or simplify the subsequent cleaning process, leading to a dramatic rationalization of the reticle manufacturing process. .

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a procedure for manufacturing a pellicle and a method for adhering a pellicle frame to a reticle.

[Explanation of symbols]

 (1) pellicle film, (2) reticle, (3) adhesive, (4) adhesive, (5) frame.

Claims (4)

[Claims] 1. A method for removing a pellicle, comprising: removing a pellicle from a reticle while heating an adhesive layer between the pellicle and the reticle. 2. The pellicle peeling method according to claim 1, wherein the heating method of the pressure-sensitive adhesive layer is based on radiant heat or heat conduction. 3. The method for removing a pellicle according to claim 1, wherein the method for heating the pressure-sensitive adhesive layer is based on direct heating of the pellicle frame using high-frequency induction heating. 4. The method according to claim 1, wherein the heating temperature of the pressure-sensitive adhesive layer between the pellicle and the reticle is 40 ° C. to 150 ° C.