JP3026637B2 - Pellicle frame peeling method - 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 used for the purpose of preventing foreign substances from adhering to a transparent substrate (hereinafter, abbreviated as a mask) such as a photomask or a reticle used in a lithography process of an LSI or a liquid crystal. It relates to a method of improvement in use. More specifically, the present invention relates to a method of peeling a pellicle frame from a mask, which can be easily peeled off when it is required after being mounted on a mask. Here, generally, the entirety including the pellicle film stretched on the pellicle frame is called a pellicle.

[0002]

2. Description of the Related Art In the production of semiconductors, liquid crystals, etc., a wafer is used.
When a fine circuit pattern is formed thereon, a manufacturing apparatus such as a stepper is used. What is important here is the quality of a mask for forming a circuit pattern to be incorporated in the manufacturing apparatus. In recent years, patterns have become finer, and it is expected that the trend will continue in the future. Therefore, the quality of a mask has a great influence on the operation rate and manufacturing cost of a manufacturing apparatus. In particular, it is a serious problem that foreign matter adhering to the mask lowers the yield. As one means for solving this problem, a method of mounting a so-called pellicle to protect the mask from foreign substances has been adopted (for example, see Japanese Patent Publication No. 54-28716). On the other hand, the pattern is being customized and the direction of high-mix low-volume production is being determined, which means that a large number of masks must be used.
The need for mask storage management has increased. At that time, it has been recognized that storage of the pellicle is easy to manage.

FIG. 2 is an explanatory view 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 and bulges. The other end surface of the support frame 2 has a double-sided adhesive tape 4 on which a protective film 5 is disposed. Such a pellicle is used by peeling off the protective film 5 and attaching it to a mask via an adhesive layer of a double-sided adhesive tape.

Incidentally, when the optical thin film 1 is damaged or broken during mounting or after mounting, foreign matter is found to adhere to the mask surface, or foreign matter that cannot be removed by blowing (gas blowing) or the like. Must be replaced with a new pellicle if it has adhered to the optical thin film. At that time, the pellicle must be peeled off from the mask. This peeling is a rather rough operation, that is, the optical thin film is first broken, the support frame is sandwiched between pliers, and a driver or the like is inserted between the mask surface and the adhesive surface of the double-sided adhesive tape layer to remove with a strong force. Is done in such a way.

[0005] Several proposals have been made so far as improvements. For example, Japanese Patent Application Laid-Open No. 61-16984
Japanese Patent Application Laid-Open No. 8 (1996) -1995 discloses a method in which an opening is provided in a part of a support frame, and a special jig is inserted into the opening to peel off. In this method, the mask is less likely to be scratched, but the adhesive substance of the double-sided adhesive tape remains on the mask surface, and it takes time to remove the adhesive. In particular, it is not a preferable method in a situation where micron-order debris cannot be tolerated with recent pattern miniaturization. Japanese Patent Application Laid-Open No. 60-147737 proposes a structure in which a support frame itself can be separated into a mask side and a pellicle side. According to this proposal, although the work of replacing the pellicle is facilitated, a problem remains with respect to the peeling of the adhesive layer on the mask side. A proposal to change the structure of the support frame in the same manner
No. 193151. Further, JP-A-60-7
Japanese Patent No. 5835 proposes to reduce the adhesive strength of the double-sided adhesive tape on the mask side. However, although the peeling is slightly easier , it cannot be a drastic improvement. If the adhesive strength is too low, the risk of the pellicle falling from the mask during the operation increases.

[0006]

In the above-mentioned method of peeling a pellicle from a mask, a layer constituting an adhesive layer remains on the mask after peeling , and a great deal of labor is required for cleaning the mask. . In addition, when inspection is performed assuming that cleaning has been completed, minute debris remains.
Further, the change to the structure of the support frame exemplified above cannot be a fundamental improvement for peeling off the pellicle from the mask without leaving the components of the adhesive layer.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method of peeling without leaving a residue of a component of an adhesive layer on a mask even after a pellicle is put on the mask. Is what you do.

[0008]

As described above, the pellicle must be firmly attached to the mask when it is adhered to the mask, but it is important that the pellicle be peeled off when necessary so that no debris remains. The present inventors have conducted intensive studies on the type of solvent in consideration of the physical properties of the adhesive layer, and as a result, have completed the present invention. That is, the present invention provides a method of peeling a pellicle frame having an adhesive layer from a mask surface to which the frame is adhered via an adhesive layer, wherein the pellicle frame is immersed in a solvent that swells or dissolves at least the adhesive layer. A pellicle frame peeling method characterized in that the pressure-sensitive adhesive layer is less swellable or less soluble than the solvent and is immersed in a solution that is miscible with the solvent, and the frame is peeled off from the mask surface. is there. Thus 2
It is surprising that the use of the seed solution minimizes the debris of the adhesive layer on the mask surface.

The present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a portion of a support frame and a double-sided adhesive tape. 4
a is an adhesive layer, for example, acrylic, rubber, vinyl,
It is made of an epoxy or silicone adhesive. Reference numeral 4b denotes a double-sided adhesive tape base material, which is made of an elastic material such as rubber or polyurethane foam. The mask surface is bonded to the support frame via the adhesive layer 4a. Where
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 the study by the present inventors, it has been found that one of the important points at the time of peeling is to first lift the peripheral portion of the adhesive layer corresponding to the end of the support frame from the mask. Otherwise, a large amount of the adhesive layer 4a will remain on the mask. It has been found that once the part floats, the other part can be peeled off quite easily with less force as long as the substrate of 4b is firm. Therefore, it is only necessary to take a method in which the peripheral portion is first lifted from the mask surface, and thereafter, the adhesive layer is peeled off without further changing the physical properties. The present invention has been made based on such an idea.

First, at least the adhesive layer is immersed in a solvent that swells or dissolves. Thus, the peripheral portion of the adhesive layer in contact with the mask surface can be raised above the mask surface. The solvent at this time is a solvent that swells or dissolves the components constituting the above-mentioned adhesive layer, and a general organic solvent or a mixture thereof can be used. For example, aromatic solvents such as toluene, ketone solvents such as acetone,
It is an alcohol solvent such as ethanol. Alcohol is preferred in view of safety and the following operation. In particular, a long-chain alcohol of ethanol or more is preferred. For example, 1-propanol, 2-propanol, 1-butanol and the like. Methanol has a drawback that it has a small swelling property and solubility and takes too much time.

Next, the adhesive layer is immersed in a solution which is less likely to swell or dissolve than the solvent. By doing so, the adhesive layer that has once been dissolved or has been dissolved in a small amount is maintained as it is. Otherwise, the above-mentioned solvent gradually enters between the mask surface and the adhesive layer, and the adhesive surface and the peeling surface are mixed, so that the remaining amount of the adhesive layer on the mask surface after the peeling increases. The nature of the solution is required to be miscible with the first solvent. Otherwise, non-uniform residues are observed. As such a solution, water, a water-alcohol solvent, and an alcohol solvent are suitable. For example,
If 1-propanol is used for the first solvent, methanol or methanol-water is used for the second solution. If 1-butanol is used as the first solvent, ethanol or ethanol-water will be used for the solution.

Generally, the thickness of the double-sided adhesive tape layer is 0.1 m.
Although it is about m to 2.0 mm, it is considerably thick at about 1.0 mm in order to eliminate mounting errors with the mask. The adhesive strength of the pressure-sensitive adhesive layer is quite strong at 100 to 1000 g / cm in order to prevent falling during the work after the mask is mounted (the value of the adhesive strength is according to JIS Z-0237 adhesion test method).

As the optical thin film, those having a single layer or those having an antireflection layer can be used. As a material for the film constituting the central layer, an inorganic substance such as quartz or a polymer can be used. Examples of the polymer include polyethylene terephthalate, cellulose esters, polycarbonate, polymethyl methacrylate, and the like. In particular, nitrocellulose and cellulose acetate are used as generally preferred materials. As the material of the antireflection layer, inorganic materials and polystyrene MgF ₂ or the like, polymers such as Teflon can be used.

An aluminum alloy, plastic, or the like can be used as the support frame. The pellicle is stored in a clean case until it is used to prevent dust from adhering. Hereinafter, the present invention will be described in more detail by way of examples.

[0015]

【Example】

[0016]

Example 1 A 1.8 mM double-sided pressure-sensitive adhesive tape having a base material of chloroprene rubber and a pressure-sensitive adhesive layer of acrylic was mounted on a support frame made of an aluminum alloy of a pellicle, and then mounted on a quartz mask provided with chromium. After standing for one week, the substrate was immersed in 1-butanol for 30 minutes, then immersed in methanol kept at about 10 ° C. for 10 minutes, and the support frame was lifted in the solution. There was almost no sticky layer debris on the mask surface.

[0017]

Example 2 The same operation as in Example 1 was performed except that 1-butanol was changed to 2-propanol.
By the way, it was in a very good residual state.

[0018]

Example 3 The same operation was performed as in Example 1 except that 1-butanol was changed to methyl ethyl ketone, but the remaining amount of the adhesive layer on the mask surface was within a desirable range.

[0019]

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

[Brief description of the drawings]

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

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

[Explanation of symbols]

 1. 1. Optical thin film body Support frame 3. Adhesive layer 4. 4. Double-sided adhesive tape Protective film 4a. Adhesive layer 4b. Base material of double-sided adhesive tape

Continuation of the front page (56) References JP-A-2-304439 (JP, A) JP-A-3-20737 (JP, A) JP-A-3-25442 (JP, A) JP-A-3-119356 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03F 1/00-1/16

Claims (1)

(57) [Claims] In a method of peeling a pellicle frame having an adhesive layer from a mask surface to which the frame is adhered via an adhesive layer, at least after immersing in a solvent that swells or dissolves the adhesive layer, A method for peeling a pellicle frame, comprising immersing the pressure-sensitive adhesive layer in a solution that is less likely to swell or dissolve than the solvent and that is miscible with the solvent, and peeling the frame from the mask surface.