JPH0264540A - Pellicle with which dust generation is prevented - Google Patents

Abstract

PURPOSE:To seal the source for generating dust of the pellicle by applying tacky adhesive materials on the cutting surfaces of a tacky adhesive tape stuck to a supporting frame. CONSTITUTION:A thin optical film 1 is fixed by an adhesive layer 3 to one side of the supporting frame 2 and a protective film 5 is stuck by a double- coated tacky adhesive tape 6 consisting of a preform base material to the other side thereof. The tacky adhesive material layers 7, 8 are formed by application of a tacky adhesive agent on the cutting surface of the tape 6. This pellicle is used by stripping the film 5 and superposing the tape 6 surface on a mask. The microhole part of the cutting surface of the tape 6 is sealed when the layers 7, 8 are provided; therefore, the trouble by the foreign matter in the hole part is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The purpose of this invention is to prevent foreign matter from adhering to transparent substrates (hereinafter referred to as masks) such as photomasks and redicles used in the lithography process of LSI manufacturing. Concerning the pellicle used. More specifically, the present invention relates to a peckle having a foam-based double-sided adhesive tape that prevents dust generation.

[Prior Art] When forming fine circuit patterns on a wafer in semiconductor manufacturing, semiconductor manufacturing equipment such as a stepper is used. What is important here is the quality of the mask for forming the circuit pattern incorporated into the semiconductor manufacturing equipment. In recent years, with the development of large-scale integrated circuits, the line width has become extremely fine, and this trend is expected to continue in the future.Therefore, the quality of masks has a large impact on the operating rate and manufacturing costs of semiconductor manufacturing equipment. It's becoming a thing. It is particularly important that foreign matter adhering to the mask reduces the yield. One way to solve this problem is to protect the mask from foreign substances by attaching a so-called pellicle (for example, see Japanese Patent Publication No. 54-28716). On the other hand, as large-scale integrated circuits are becoming more customizable, there is a growing trend toward high-mix, low-volume production, which means the use of a large number of masks, and the need for mask storage management has increased. In this case, it is becoming recognized that storage with a pellicle attached is convenient for management.

In such a mask pellicle, a foam-based double-sided adhesive tape is attached to the pellicle frame or an adhesive material is laminated on the pellicle frame in order to attach it to the mask. At that time, since the laminated type of adhesive material lacks elasticity, it is difficult to attach it to the mask (and there is a high possibility that the expensive pellicle will be defective at the time of attachment. Double-sided adhesive tape is often used.

[Problems to be Solved by the Invention] However, even when a pellicle using a foam-based double-sided adhesive tape is attached, minute foreign matter often adheres to the mask surface or the optical thin film surface.
Problems sometimes occurred after wearing the mask.

In view of these circumstances, it is an object of the present invention to provide a pellicle with higher reliability and safety.

[Means for Solving the Problems] The present inventors have conducted various studies to solve the above-mentioned problems, but have discovered that the cause of minute foreign matter adhesion has appeared on the cutting surface of the foam-based double-sided adhesive tape. It was discovered that there is a microscopic pore that exits. That is, minute foreign matter enters the micropore during the pellicle manufacturing process, and this becomes a source of dust, causing the foreign matter to adhere to the attached mask surface and the optical thin film surface of the pellicle. It was also confirmed that it is extremely difficult to remove foreign substances that have entered the micropores from the micropores.

Therefore, as a result of further research into a method for sealing the micropores exposed on the cutting surface, it was confirmed that providing an adhesive layer on the cutting surface is effective, leading to the present invention. .

That is, the present invention is a pellicle that is prevented from developing, characterized in that an adhesive layer is provided on the cutting surface of a foam-based double-sided adhesive tape disposed on one end surface of a support frame.

The present invention will be explained below with reference to the drawings.

FIG. 2 shows the construction of a pellicle having a conventional type of foam-based double-sided adhesive tape. Optical thin film ■ is support frame 2
It is fixed without wrinkles or sagging by the 3-layer adhesive layer. A double-sided tape 4 is provided on the other end surface of the support frame 2, and a protective film 5 is placed on the tape. FIG. 1 shows a pellicle having a foam-based double-sided adhesive tape 6 that has been subjected to dust prevention treatment according to the present invention. An adhesive layer is provided on the cutting surface [(7) and/or (8) in FIG. 2] of this foam-based double-sided adhesive tape interposed between the support frame 2 and the protective film 5.

The material of the support frame 2 is usually aluminum alloy, plastic, etc., and its size is about 1 to 81 inches in diameter and 1 to 8 inches square, depending on the size of the mask.
Its height is about 2 to 10 mm. Optical thin films can be made from commonly used materials with high light transmittance such as nitrocellulose or cellulose acetate, or thin films with so-called anti-reflection layers on both or one side can also be used. can.

As the foam-based double-sided adhesive tape, both the so-called double-sided foam tape in which the foam base material and the adhesive layer are laminated on the spot, and the so-called double-sided foam tape in which the adhesive material and the foam base material are integrated can be used in the present invention. can do. Examples of the foam base material include plastic or rubber foams such as polyurethane, polychloroprene, and polyethylene, and examples of the adhesive include acrylic, silicone, and rubber adhesives.

The sealing adhesive for forming the adhesive layer is not particularly limited, and for example, commercially available adhesives dissolved in water or organic solvents can also be used. As a method for applying these adhesives, brushing, dipping, etc. can be used.

The pellicle is ready for use. It will be stored in a clean case until then. When in use, the protective film 5 is peeled off and the face 6 is attached to the mask. In the case of a stepper, since the effects of foreign objects are extremely sensitive, it is common to mount a pellicle not only on the image side of the mask but also on other surfaces.

〔Example] The present invention will be explained in more detail with reference to Examples below.

Example 1 An aluminum alloy was used as the support frame, and a sheet-like double-sided foam tape No. 42 manufactured by Sumitomo 3M Kagi Co., Ltd. was attached to the end surface of the aluminum alloy.
62 was glued on and the excess was cut off with a knife. If you look at its cross section under a microscope, you will see that it has many tiny pores.

Next, an aqueous solution of S P-111,7 manufactured by Sumitomo 3M Kansha Co., Ltd. was applied to the cut end of the double-sided foam tape and dried to form a sticky layer on the cut surface. When the thus treated cut surface was observed under a microscope, it was found that the micropores were completely sealed. A pellicle was made using the support frame obtained in this way. The process involved drying a nitrocellulose solution coated on a smooth substrate using a commonly used spin coating method. Next, the nitrocellulose thin film was peeled off, and the support frame was adhered with an epoxy adhesive. Strong air was blown with an air gun onto the cut portion of the double-sided foam tape of the completed pellicle. Thereafter, the pellicle surface was subjected to a surface inspection machine (HLD-LOOM manufactured by Hitachi Electronic Engineering ■), but the number of foreign substances did not increase before and after spraying with an air gun. It is clear that double-sided foam tape is no longer a source of development due to dust prevention treatment.

[Effects of the Invention] As explained above, the pellicle according to the configuration of the present invention has the following effects:
The source of dust generation can be sealed, further improving quality and reliability.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a pellicle treated with the dust generation prevention part of the present invention, and Fig. 2 is a sectional view of a conventional type pellicle. 1... Optical thin film, 2... Support frame, 6... Foam base double-sided adhesive tape, 7.8... Adhesive layer.

Claims (1)

[Claims] A pellicle that prevents dust generation, characterized in that an adhesive layer is provided on the cutting surface of a foam-based double-sided adhesive tape disposed on one end surface of a support frame.