JPH04366845A - Method for peeling pellicle frame body - Google Patents

Abstract

PURPOSE:To prevent a tacky adhesive layer of a pellicle from remaining on a mask by immersing the pellicle into a solvent which swells or dissolves the tacky adhesive layer, then immersing the pellicle into a which can be intimately mixed-with the solvent, thereby peeling the tacky adhesive layer from the mask surface. CONSTITUTION:The mask surface is adhered via the tacky adhesive layer 4a of a double coated tacky adhesive tape base material 4b to a supporting frame 2. It is imperative that the entire part of the surface of the tacky adhesive layer 4a be in tight contact with the mask surface, but the entire part of the surface of the tacky adhesive layer solution needs be peeled from the mask surface if an operator once tries to peel the pellicle from the mask surface. The tacky adhesive layer 4a is, therefore, immersed into the solvent which swells or dissolves the tacky adhesive layer, by which the peripheral part of the tacky adhesive layer 4a in contact with the mask surface is floated from the mask surface. The pellicle is then immersed into the 4a which more hardly swells or dissolves the tacky adhesive layer 4a than the solvent and can be intimately mixed with the solvent. The tacky adhesive layer 4a which is once begun to be dissolved or is slightly dissolved is maintained as it is. The frame body 2 is peeled from the mask surface in such a manner.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention relates to a pellicle used for the purpose of preventing foreign matter from adhering to transparent substrates (hereinafter referred to as masks) such as photomasks and reticles used in the lithography process of LSI and liquid crystal. Concerning improvements in usage. More specifically, the present invention relates to a method for peeling a pellicle frame from a mask, which allows easy peeling when peeling is required after being attached to a mask. Here, the entire pellicle, including the pellicle membrane stretched over the pellicle frame, is generally referred to as a pellicle.

0002

[Prior art] Wafers are used in the production of semiconductors, liquid crystals, etc.
In order to form a fine circuit pattern thereon, a manufacturing device such as a stepper is used. What is important here is the quality of the mask for forming the circuit pattern incorporated into the manufacturing equipment. In recent years, patterns have become finer, and this trend is expected to continue in the future. Therefore, the quality of the mask has come to have a large impact on the operating rate of manufacturing equipment and manufacturing costs. In particular, it is a serious problem 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, patterns are becoming more customizable and there is an increasing 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.

FIG. 2 is an explanatory diagram of a pellicle used in such a place. Here, the optical thin film body 1 is fixed to the support frame 2 by the adhesive layer 3 without wrinkles or sagging. The support frame 2 has a double-sided adhesive tape 4 on the other end surface, and a protective film 5 is placed on top of the double-sided adhesive tape 4. Such a pellicle is used by peeling off the protective film 5 and attaching it to a mask via the adhesive layer of double-sided adhesive tape.

By the way, if the optical thin film 1 is damaged or torn during installation or during work after installation, or if foreign matter is found on the mask surface, or foreign matter cannot be removed by blowing (gas spraying), etc. If the pellicle is found to be attached to the optical thin film, it will be necessary to replace it with a new pellicle. At that time, of course, the pellicle must be peeled off from the mask. This peeling requires a very rough operation; first, the optical thin film is broken, the support frame is held in place with pliers, etc., and a screwdriver, etc. is inserted between the mask surface and the adhesive surface of the double-sided adhesive tape layer, and the mask is pried open with strong force. It is done in a certain way.

[0005] Several proposals have been made to improve this. For example, JP-A-61-16984
According to the 8th Publication, an opening is provided in a part of the support frame, and a special jig is inserted into the opening to peel off the support frame. Although this method reduces the chances of scratches on the mask, it leaves sticky residue from the double-sided adhesive tape on the mask surface, which requires time and effort to remove. This is by no means a preferable method, especially under the circumstances where micron-order debris cannot be tolerated as patterns become finer in recent years. Furthermore, Japanese Patent Laid-Open No. 60-147737 proposes a structure in which the support frame itself can be separated into a mask side and a pellicle side. Although this proposal makes it easier to replace the pellicle, the problem of peeling of the adhesive layer on the mask side remains. A proposal to change the structure of the support frame in the same way was published in Japanese Patent Application Laid-Open No. 1986.
It is also in the -193151 publication. Furthermore, JP-A-60-7
Japanese Patent No. 5835 proposes weakening the adhesive strength of the double-sided adhesive tape on the mask side. However, in terms of peeling, although it is slightly easier, it does not result in a drastic improvement. Furthermore, if the adhesive strength is weakened too much, the risk of the pellicle falling from the mask during work increases.

[0006]

[Problems to be Solved by the Invention] In the method for peeling off the pellicle from the mask as described above, the layer constituting the adhesive layer remains on the mask after peeling off, and cleaning the mask requires a great deal of effort. . Moreover, even if the cleaning has been completed, it is inevitable that minute debris will remain when inspected. Moreover, the changes to the structure of the support frame as exemplified above cannot provide a fundamental improvement in peeling off the pellicle from the mask without leaving any components of the adhesive layer.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a peeling method that does not leave any residue of the adhesive layer on the mask even after the pellicle is peeled off from the mask. It is something to do.

[0008]

[Means for Solving the Problems] As mentioned above, when a pellicle is bonded to a mask, it must be firmly attached, but it is important to peel it off when necessary so that no debris remains. The present inventors have completed the present invention as a result of intensive study on the type of solvent in consideration of the physical properties of the adhesive layer. That is, the present invention provides a method for peeling a pellicle frame having an adhesive layer from a mask surface to which the frame is adhered via an adhesive layer, after at least infiltrating the adhesive layer with a solvent that swells or dissolves the adhesive layer. A method for peeling off a pellicle frame, which comprises immersing the adhesive layer in a solution that is less likely to swell or dissolve than the solvent and is miscible with the solvent, and then peeling off the frame from the mask surface. be. It is surprising that the residue of the adhesive layer on the mask surface can be minimized by using two kinds of solutions in this way.

The present invention will be explained below with reference to the drawings. FIG. 1 is a sectional view of the support frame and double-sided adhesive tape. 4
a is an adhesive layer, such as acrylic, rubber, vinyl, etc.
It is made of epoxy, silicone, etc. adhesive. 4b is a double-sided adhesive tape base material, which is made of an elastic material such as rubber or polyurethane foam. The mask surface is adhered to the support frame via the adhesive layer 4a. By the way, 4
It is important that the entire surface of 4a is in close contact with the mask surface, but once the pellicle is to be peeled off from the mask surface, the entire surface of 4a must be peeled off from the mask surface. As a result of studies conducted by the present inventors, it was found that one of the important points during peeling is to first float the peripheral portion of the adhesive layer corresponding to the edge of the support frame above the mask. Otherwise, a large amount of the adhesive layer 4a will remain on the mask. It has been found that once that part has lifted, the other parts can be peeled off fairly easily with little force, as long as the base material of 4b is solid. Therefore, it is better to first raise the peripheral portion above the mask surface and then peel it off without changing the physical properties of the adhesive layer any further. The present invention was created based on this idea.

First, at least the adhesive layer is soaked in a solvent that swells or dissolves it. This allows the peripheral portion of the adhesive layer that is in contact with the mask surface to be lifted above the mask surface. The solvent in this case is a solvent that swells or dissolves the components constituting the adhesive layer described above, and general organic solvents or mixtures thereof can be used. For example, aromatic solvents such as toluene, ketone solvents such as acetone,
An alcoholic solvent such as ethanol. Alcohol-based solvents are preferred from the viewpoint of safety and subsequent operations. Especially ethanol
Preferably, the alcohol has a long chain longer than 1. For example, 1-propanol, 2-propanol, 1-butanol, etc. Methanol has the disadvantage of low swelling and solubility and takes too much time.

Next, the adhesive layer is immersed in a solution that is less likely to swell or dissolve than the above solvent. By doing this, the adhesive layer that has once started to dissolve or has dissolved to a small extent is maintained as it is. Otherwise, the solvent will gradually enter between the mask surface and the adhesive layer, the adhesive surface and the peeled surface will coexist, and the amount of adhesive layer remaining on the mask surface after peeling will increase. The nature of this solution requires that it be miscible with the first solvent. Otherwise, uneven residue will be observed. Suitable examples of such a solution include water, water-alcoholic solvents, and alcoholic solvents. For example, if 1-propanol is used as the first solvent, methanol or methanol-water can be used as the second solution. If 1-butanol is used as the first solvent, ethanol or ethanol-water may be used in the solution.

[0012] Generally, the thickness of the double-sided adhesive tape layer is 0.1 m.
The thickness is approximately 2.0 mm, but it is considerably thick at approximately 1.0 mm in order to prevent mistakes when attaching the mask to the mask. In order to prevent the mask from falling during work after wearing, the adhesive force of the adhesive layer is quite strong, ranging from 100 to 1000 g/cm (adhesive force values are based on the JIS Z-0237 adhesive force test method).

[0013] As the optical thin film, a single layer film or a film having an antireflection layer can be used. Inorganic substances such as quartz or polymers can be used as the material for the film constituting the central layer. Examples of the polymer include polyethylene terephthalate, cellulose esters, polycarbonate, and polymethyl methacrylate. In particular, nitrocellulose and cellulose acetate are generally preferred materials. As the material for the antireflection layer, inorganic materials such as MgF2 and polymers such as polystyrene and Teflon can be used.

[0014] As the support frame, aluminum alloy, plastic, etc. can be used. The pellicle is stored in a clean case until it is ready for use to prevent dust from adhering to it. The present invention will be explained in more detail with reference to Examples below.

[0015]

【Example】

[0016]

Example 1 A double-sided adhesive tape having a thickness of 1.8 mm and having a base material of chloroprene rubber and an acrylic adhesive layer was attached to a support frame made of an aluminum alloy of a pellicle, and then attached to a chromium-coated quartz mask. After leaving it for one week, it was immersed in 1-butanol for 30 minutes, then immersed in methanol heated to about 10°C for 10 minutes, and the support frame was lifted in the solution. There was almost no adhesive residue on the mask surface.

[0017]

[Example 2] The same operation as in Example 1 was performed except that 1-butanol was replaced with 2-propanol, but Example 1
By the way, it has remained in very good condition.

[0018]

Example 3 The same procedure as in Example 1 was carried out except that methyl ethyl ketone was used instead of 1-butanol, but the amount of adhesive layer remaining on the mask surface was within the desired range.

[0019]

As explained above, according to the method of peeling a pellicle from a mask of the present invention, the amount of adhesive layer remaining on the mask surface after peeling can be extremely reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a pellicle support frame and a double-sided adhesive tape layer.

FIG. 2 is an explanatory diagram of a general pellicle.

[Explanation of symbols]

1. optical thin film body 2. support frame 3. adhesive layer 4. double-sided adhesive tape 5. Protective film 4a. adhesive layer 4b. Base material for double-sided adhesive tape

Claims (1)

[Claims] Claims: 1. A method for peeling a pellicle frame having an adhesive layer from a mask surface to which the frame is adhered via an adhesive layer, after at least infiltrating the adhesive layer with a solvent that swells or dissolves the adhesive layer. A method for peeling off a pellicle frame, which comprises immersing the adhesive layer in a solution that is less likely to swell or dissolve than the solvent and which is miscible with the solvent, and then peeling off the frame from the mask surface.