Labels for Pellicle Cases

Abstract

This product provides a label for pellicle cases that is less prone to application problems and less likely to peel off even after time has passed or after annealing treatment. [Solution] A label for a pellicle case that is attached to a pellicle case for storing a pellicle, comprising a label sheet and a label adhesive layer for attaching the label sheet to the pellicle case, wherein the label adhesive layer has a matrix-shaped uneven structure on the surface to be attached to the pellicle case.

Description

Technical Field

[0001] The present invention relates to a label for a pellicle case (also simply referred to as a case) that is attached to a pellicle case for storing a lithography pellicle used for removing dust from a photomask in the manufacture of semiconductor devices, liquid crystal displays, and the like.

Background Art

[0002] In the manufacture of semiconductor devices such as LSI and super LSI, or liquid crystal displays, a photolithography technique is used to irradiate a semiconductor wafer or a liquid crystal substrate with light to form a pattern (Patent Document 1). In this photolithography process, when dust adheres to a photomask (exposure original plate), since the dust absorbs light or bends light, problems occur such as deformation of the transferred pattern, rough edges, blackening and soiling of the substrate, etc., where dimensions, quality, and appearance are impaired. For this reason, usually, these operations are performed in a clean room, but it is difficult to keep the photomask completely clean even in the clean room. Therefore, as a dust removal method, a method of attaching a pellicle that transmits exposure light well to the surface of the photomask is generally performed. As a result, the dust does not directly adhere to the surface of the photomask but adheres to the pellicle film. Therefore, if the focus is adjusted to the pattern on the photomask during exposure, the dust on the pellicle film becomes irrelevant to the transfer.

[0003] The configuration of a general pellicle will be described. A pellicle film that transmits exposure light well is stretched via an adhesive on the upper end surface of an aluminum alloy pellicle frame, and a pellicle adhesive layer for attaching the pellicle to the photomask is formed on the lower end surface of the pellicle frame. Further, a separator for protecting the pellicle adhesive layer may be detachably provided on the lower end surface of the pellicle adhesive layer. Such a pellicle is installed so as to cover the pattern area formed on the surface of the photomask. Therefore, this pattern area is isolated from the outside by the pellicle, and dust adhesion to the photomask is prevented.

[0004] The pellicle is stored in a special case during transport until it is attached to the photomask. These pellicle cases are typically injection-molded from resin. A label indicating the pellicle's product name and lot number is attached to the case.

[0005] In recent years, LSI design rules have been miniaturized to the sub-quarter micron level, and consequently, the particle size that needs to be controlled for contamination has also become smaller. Furthermore, the wavelength of exposure light sources has become shorter, making it easier for fine particles such as haze to be generated during exposure. As a result, control over outgassing to the pellicle and contamination to ions has become stricter. Therefore, materials with low contamination (such as polycarbonate resin) are now being used for the pellicle case that houses the pellicle. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-160364 [Overview of the project] [Problems that the invention aims to solve]

[0007] Labels applied to pellicle cases are required to adhere well to injection-molded pellicle cases. Labels are typically applied to the center of the pellicle case lid. The center of the pellicle case lid usually has a gate mark from the injection molding process. These gate marks are often uneven, which can cause problems such as the label lifting or lifting when applied. Furthermore, when using a pellicle automounter to attach pellicles to a photomask, it is common practice to use an air chuck to chuck the pellicle case lid near the center and pull it up when removing the pellicle from the case. If there is a problem with the label's application, there is a risk that the label will peel off when chucked with the air chuck.

[0008] Incidentally, the pellicles are shipped after being annealed (for example, at around 100°C). However, to avoid the risk of contamination of the pellicles during this process, they are annealed while still in their pellicle cases. At this time, the labels that have been affixed over the gate marks may peel off, and it may become necessary to re-apply the labels after annealing. This is because, after the labels are applied, the air remaining in the recessed areas of the gate marks expands during annealing, creating large bubbles, which in turn causes the labels to peel off. When multiple pellicle cases are annealed, the peeling of the labels makes it impossible to determine which pellicle case corresponds to which label (which ID number the contained pellicles belong to).

[0009] The present invention was made to solve the above problems and aims to provide a label for pellicle cases that is less prone to adhesion defects and less likely to peel off even after time has passed or after annealing treatment. [Means for solving the problem]

[0010] To achieve the above objective, the present invention provides a label for a pellicle case that is attached to a pellicle case for storing a pellicle, It comprises a label sheet and a label adhesive layer for attaching the label sheet to the pellicle case. The label adhesive layer is characterized in that the surface on which it is attached to the pellicle case has a matrix-shaped uneven structure, providing a label for pellicle cases.

[0011] With the label for pellicle cases of the present invention, even if residual air in the gate marks expands after annealing, the above-described matrix-shaped uneven structure allows for better bubble release than conventional products (where a uniform thickness adhesive layer is formed on the entire back surface of the label). Therefore, it is possible to very effectively prevent label peeling, which occurred with conventional products due to improper bubble release. Furthermore, even if bubbles remain in the present invention, they can be easily removed and repaired without having to reapply the label. Furthermore, it allows for proper air release during application, preventing problems such as lifting and making it possible to attach it to the pellicle case. Even after time has passed since application, the aforementioned application problems are unlikely to occur. Even if an application problem does occur, it is minor and can be easily repaired.

[0012] In this case, the uneven structure of the label adhesive layer can be such that the thickness of the raised portion is 10 μm or more and 60 μm or less.

[0013] With this type of material, being 10 μm or thicker, the adhesion stability to the pellicle case can be further improved. Also, because it is 60 μm or less, the step along the outer edge of the label when attached to the pellicle case can be kept to a minimum so that it is not noticeable.

[0014] Furthermore, the uneven structure of the label adhesive layer can be such that the difference in thickness between the recessed and raised portions is 5 μm or more and 50 μm or less.

[0015] With this type of design, there is adequate ventilation space, making it easier to remove air bubbles during application and to eliminate any bubbles that may form, while also minimizing the difference in height between recessed and raised areas.

[0016] Furthermore, the matrix shape of the label adhesive layer can be 30 mesh or more and 70 mesh or less.

[0017] If it is such a thing, since it is 30 mesh or more, the smoothness of the label sheet can be made better, and printing of letters or barcodes on the surface of the label sheet can be performed more stably. Also, since it is 70 mesh or less, an appropriate ventilation space can be secured, and air bleeding during pasting and air bleeding when bubbles are generated due to environmental temperature changes can be performed more effectively.

[0018] Further, the adhesive of the label adhesive layer can be an acrylic adhesive.

[0019] If it is such a thing, for example, it is good for pasting on a pellicle case made of polycarbonate resin.

[0020] Further, the adhesive strength of the adhesive of the label adhesive layer can be 1.2 N / 25 mm or more and 4.0 N / 25 mm or less with respect to polycarbonate.

[0021] If it is such a thing, since it is 1.2 N / 25 mm or more, the pasting strength can be made more sufficient. Also, since it is 4.0 N / 25 mm or less, adhesive residue when the label is peeled off can be effectively prevented.

[0022] Further, the penetration of the adhesive of the label adhesive layer can be 5 or more and 30 or less.

[0023] If it is such a thing, when pasting on a pellicle case, it is possible to secure a space for air bleeding and air bleeding of bubbles while maintaining sufficient pasting strength.

[0024] Further, the label sheet can be made of white PET.

[0025] If it is such a thing, it can be excellent in printability on the label sheet and difficult to generate dust.

Advantages of the Invention

[0026] The label for pellicle cases of the present invention can be easily and flawlessly applied to the pellicle case. Furthermore, even if time passes or the ambient temperature changes after application, air bubbles can be suppressed or easily removed. Therefore, peeling of the label can be prevented. [Brief explanation of the drawing]

[0027] [Figure 1] This is an explanatory diagram showing an example of a label for a pellicle case according to the present invention. [Figure 2] This is an explanatory diagram showing an example of a bonding surface (with a fine mesh). [Figure 3] This is an explanatory diagram showing another example of a label for a pellicle case according to the present invention. [Figure 4] This is an explanatory diagram showing another example of a bonding surface (with a coarse mesh). [Modes for carrying out the invention]

[0028] The present invention will be described in detail below with reference to the figures as an example of an embodiment, but the present invention is not limited to these. As mentioned earlier, with regard to labels for pellicle cases, it was sometimes impossible to eliminate air bubbles that formed over time after application or during the annealing process, or the labels would peel off. Therefore, the inventors conducted intensive research and discovered that a label for a pellicle case, which is attached to a pellicle case that houses a pellicle, comprises a label sheet and a label adhesive layer for attaching the label sheet to the pellicle case, and that if the label adhesive layer is a pellicle case label with a matrix-shaped uneven structure on the surface to be attached to the pellicle case, it is possible to prevent the label from peeling off as described above (or, even if defects such as air bubbles occur temporarily, they can be easily repaired), eliminating the need to reapply the label as in the past, and thus completed the present invention.

[0029] Figure 1 shows an example of a label for pellicle cases according to the present invention. A pellicle case is also shown in the figure to make the orientation of the adhesive surface to the pellicle case clearer. Figure 2 shows an example of the adhesive surface to the pellicle case.

[0030] First, as shown in Figure 1, the pellicle case label (also simply called a label) 1 of the present invention comprises a label sheet 2 and a label adhesive layer (also simply called an adhesive layer) 3 for attaching the label sheet (also simply called a sheet) 2 to a pellicle case (also simply called a case) C. Before being attached to the case C, the surface of the adhesive layer 3 (the surface 4 attached to the case C) is usually protected by a release paper (not shown) that is peelably attached to it.

[0031] Furthermore, the adhesive layer 3 has a matrix-shaped uneven structure on its adhesive surface 4. Specifically, the uneven structure of the adhesive layer 3 has protrusions 5 (adhesive parts) that protrude from the back side of the sheet 2 and recesses 6 (ventilation parts) that are recessed spaces relative to the protrusions 5 (see Figure 1), and the protrusions 5 have a mesh shape (grid shape) in plan view (see Figure 2). This combination of protrusions 5 and recesses 6 results in a configuration that looks like a matrix table.

[0032] Incidentally, in the configuration shown in Figure 1, the bottom B of the recess 6 is part of the adhesive layer 3. That is, first, an adhesive layer of a predetermined thickness (the thickness from the back surface of the sheet 2 to the position of the bottom B of the recess 6) is provided over the entire back surface of the sheet 2, and the protrusion 5 is further provided with an even thicker adhesive layer from there. However, the present invention is not limited to this, and the label 1A shown in Figure 3 can also be used. That is, as in the adhesive layer 3 of label 1A, the adhesive does not have to be provided at the bottom B of the recess 6, and the adhesive may consist only of the protrusion 5. In this case, the bottom B of the recess 6 corresponds to the back surface of the sheet 2.

[0033] This matrix-shaped uneven structure makes it easy to remove air bubbles during application, allowing for flawless application without leaving any air bubbles under label 1. Furthermore, even if annealing or other processes are performed after application, causing residual air within the gate marks to expand, the expanded air easily moves from one recess 6 to an adjacent recess 6 via the convex portion 5, facilitating bubble release. As described above, bubbles are naturally released due to the expansion pressure, or even if bubbles remain between the label 1 and the pellicle case C, they can be easily released and repaired by manual pressure applied by a worker.

[0034] On the other hand, conventional products without the uneven structure of the present invention are prone to application problems, such as air bubbles remaining under the label during application. Furthermore, even if large air bubbles are generated by the expansion of air during the annealing process, they are difficult to remove, and as a result, the label may peel off. In such cases, it becomes necessary to reapply a new label. This invention is extremely beneficial because it eliminates the conventional problem of peeling and allows for easy handling of adhesion defects such as air bubbles.

[0035] Here, it is preferable that the thickness of the protrusions 5 of the adhesive layer 3 is designed to be in the range of 10 μm to 60 μm. Note that the thickness of the protrusions 5 refers to the distance from the back surface of the sheet 2 to the front surface of the protrusions 5 (i.e., the adhesive surface 4). Within this thickness range, it is possible to effectively prevent the label from being too thin, which would result in poor adhesion stability, and also prevent the label from being too thick, which would cause a noticeable step along the outer edge of label 1 when it is attached to the lid of pellicle case C.

[0036] Furthermore, it is preferable that the difference between the thickness of the protrusions 5 of the adhesive layer 3 and the thickness of the recesses 6 (the distance from the back surface of the sheet 2 to the bottom B of the recess 6) is between 5 μm and 50 μm. In the embodiment shown in Figure 3, the thickness of the recess 6 is 0 μm. If these thickness differences are within the above range, it is possible to maintain an appropriate space for air and bubbles to escape while suppressing the step difference between the convex portion 5 and the concave portion 6.

[0037] Furthermore, the matrix shape of the adhesive layer 3 is preferably in the range of 10 mesh to 100 mesh, and more preferably in the range of 30 mesh to 70 mesh. If the mesh size is, for example, 10 mesh or more, or even 30 mesh or more, the smoothness of sheet 2 will be better, making it easier to print text and barcodes. Furthermore, by using a mesh with a coarseness of, for example, 100 mesh or less, or even 70 mesh or less, it is possible to more reliably secure ventilation space when label 1 is applied, and effectively allow air to escape during application. In addition, it is possible to effectively prevent label 1 from lifting when air bubbles are generated due to changes in ambient temperature. Thus, the above-mentioned range of mesh coarseness is a favorable condition from the standpoint of ease of air and bubble release, and stability of printing, etc. Furthermore, regarding the relationship between the coarseness of the mesh and the difference in thickness between the recessed portion 6 and the convex portion 5, when the mesh coarseness is finer (for example, 100 mesh), a smaller difference in thickness is preferable in terms of air and bubble release. On the other hand, when the mesh coarser (for example, 10 mesh), even if the difference in thickness is larger, air and bubble release are not significantly hindered.

[0038] The unit "mesh" refers to the number of bumps and depressions per inch (25.4 mm). For example, if the example in Figure 2 is a Y mesh, and the width of the protrusions 5 is W1 mm ​​and the width of one side of the recess 6 (the distance between adjacent protrusions 5) is W2 mm, then the following relationship holds. (W1+W2)×Y=25.4 Therefore, for example, if W1 is constant, the finer the mesh of the protrusion 6, the larger Y will be, and conversely, the coarser the mesh, the smaller Y will be. Figure 4 shows an example where the mesh size is coarser than in Figure 2. If the configuration in Figure 4 is a Ya mesh, the relationship Y > Ya holds true between it and the Y mesh in Figure 2.

[0039] An example of a combination of W1, W2, and Y is W1=0.32mm, W2=0.21mm, and Y=48 mesh, which is particularly preferred. Furthermore, it is even more preferable that the difference in thickness between the recessed portion 6 and the convex portion 5 is 50 μm. However, the present invention is not limited to these values ​​and can be determined as appropriate. For example, a smaller value of W1 makes it easier for air bubbles to escape, but in that case, the adhesion at each protrusion 5 is considered to be weaker compared to when the value of W1 is large, so the adhesion strength can be adjusted by adjusting the mesh coarseness. The above combinations should be determined as appropriate, taking into consideration the ease of air bubble escape and the adhesion strength at the adhesive surface. Depending on the mesh coarseness, the width W1 of the protrusion 5 is preferably about 0.1 mm to 0.5 mm, and the width W2 of one side of the recess 6 is preferably about 0.1 mm to 0.5 mm.

[0040] By the way, while there are no particular limitations on the case C to which the sticker will be applied, it is generally made of polycarbonate resin or ABS resin. Furthermore, as the adhesive for the adhesive layer 3, for example, an acrylic adhesive, a silicone adhesive, or a rubber-based adhesive can be used so as to adhere well to these resins.

[0041] Furthermore, regarding this adhesive, while it is sufficient for the adhesive strength to adhere properly, it is preferable that it be within a certain range to avoid problems such as adhesive residue when peeling off label 1. For example, if case C is made of polycarbonate, the adhesive strength to polycarbonate can be between 1.2 N / 25 mm and 4.0 N / 25 mm. More preferably, it can be between 1.2 N / 25 mm and 3.8 N / 25 mm. The above adhesive strength values ​​are based on JIS Z 0237. The method for measuring adhesive strength according to JIS Z 0237 is as follows: (Measurement method) Under conditions of 23±1℃ and (50±5)% humidity, a 25mm wide strip of adhesive is applied to a polycarbonate sheet, and the strength of the peel when pulled off at a 180° angle from the adhesive surface is measured.

[0042] Furthermore, by optimizing the hardness (penetration) of the adhesive, when the matrix-shaped adhesive layer 3 is attached to the lid of case C, it is possible to maintain sufficient adhesive strength while securing space for air and bubble release. In particular, from the above viewpoint, it is preferable that the penetration is between 5 and 30. The above penetration values ​​are based on JIS K 2220. The method for measuring adhesive strength according to JIS K 2220 is as follows: (Measurement method) The adhesive is quantified by placing a cone-shaped metal piece with the pointed end facing downwards and measuring the depth to which the metal piece sinks.

[0043] Furthermore, since the pellicle's lot number, product name, and other text and barcodes are printed on the surface of sheet 2, white PET film or white coated PET film can be mainly used due to its excellent printability and low dust generation. Furthermore, the thickness of sheet 2 is not particularly limited, but it can be, for example, about 20 μm to 100 μm. [Examples]

[0044] The present invention will be described more specifically below with reference to examples of the present invention, but the present invention is not limited to these examples. (Example 1) As shown in Figure 1, a label sheet for the pellicle case of the present invention was prepared with an area of ​​65 mm x 60 mm, a sheet thickness of 50 μm, and an adhesive layer thickness of 35 μm (thickness of the raised portion: 35 μm, thickness of the recessed portion: 20 μm). The label sheet was made of white PET film, and an acrylic adhesive was used for the adhesive layer. The adhesive layer had a matrix structure with 30 mesh. Furthermore, the width of the protrusions in the adhesive layer was set to 0.50 mm, and the width of one side of the recess was set to 0.35 mm. Furthermore, the acrylic adhesive used had a penetration degree of 15 and an adhesive strength of 3.8 N / 25 mm to polycarbonate. Table 1, described later, summarizes the main labeling conditions for each example and comparative example. In Examples 2-12 and the comparative example, sections with conditions different from Example 1 are shown in bold and shaded.

[0045] After printing a barcode containing information such as the pellicle's lot number onto this label, the label was attached to the center of the precisely cleaned black polycarbonate pellicle case lid, covering the injection molding gate marks.

[0046] <Rating> After storing the attached labels at room temperature for 7 days and checking their condition, they were found to be firmly attached without any air bubbles or lifting. Furthermore, even after heating the pellicle case with the label attached at 80°C for two hours, the label remained firmly attached. Subsequently, a barcode reading test was conducted, confirming that it could be read successfully.

[0047] (Example 2) A white coated, vapor-deposited PET film was used for the label sheet. Otherwise, the same pellicle case labels as in Example 1 were prepared. After barcode printing was performed on this label in the same manner as in Example 1, it was affixed to the center of the lid of a precision-cleaned black polycarbonate pellicle case. Similar to Example 1, the labels maintained good adhesion even after being stored for 7 days or heated at 80°C for 2 hours. Subsequent barcode reading tests, similar to those conducted in Example 1, confirmed that successful reading was possible.

[0048] (Example 3) The matrix shape of the adhesive layer was set to 70 mesh. Furthermore, the width of the protrusions in the adhesive layer was set to 0.20 mm, and the width of one side of the recess was set to 0.16 mm. Otherwise, the same pellicle case labels as in Example 1 were prepared. After printing a barcode on this label in the same manner as in Example 1, it was attached to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 1. It was confirmed that both the barcode readability and the label adhesion were good.

[0049] (Example 4) The adhesive strength of the acrylic adhesive used in the adhesive layer was 1.2 N / 25 mm. Otherwise, the same pellicle case labels as in Example 1 were prepared. After printing a barcode on this label in the same manner as in Example 1, it was affixed to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 1. It was confirmed that both the barcode readability and the label adhesion were good.

[0050] (Example 5) The acrylic adhesive used in the adhesive layer had a penetration degree of 30, and the matrix shape of this adhesive layer was set to 70 mesh. In addition, the width of the convex portion of the adhesive layer was 0.20 mm, and the width of one side of the concave portion was 0.16 mm. Otherwise, the same pellicle case labels as in Example 1 were prepared. After printing a barcode on this label in the same manner as in Example 1, it was affixed to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 1. It was confirmed that both the barcode readability and the label adhesion were good.

[0051] (Example 6) The acrylic adhesive used in the adhesive layer had a penetration degree of 5, and the matrix shape of this adhesive layer was set to 70 mesh. In addition, the width of the convex portion of the adhesive layer was 0.20 mm, and the width of one side of the concave portion was 0.16 mm. Otherwise, the same pellicle case labels as in Example 1 were prepared. After printing a barcode on this label in the same manner as in Example 1, it was affixed to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 1. It was confirmed that both the barcode readability and the label adhesion were good.

[0052] (Example 7) The adhesive layer had a thickness of 10 μm (thickness of the convex portion: 10 μm, thickness of the concave portion: 6 μm), and the matrix shape of this adhesive layer was set to 70 mesh. The width of the convex portion of the adhesive layer was 0.20 mm, and the width of one side of the concave portion was 0.16 mm. Otherwise, the same pellicle case labels as in Example 1 were prepared. After printing a barcode on this label in the same manner as in Example 1, it was affixed to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 1. It was confirmed that both the barcode readability and the label adhesion were good.

[0053] (Example 8) The matrix shape of the adhesive layer was set to 20 mesh. Furthermore, the width of the protrusions in the adhesive layer was set to 0.80 mm, and the width of one side of the recess was set to 0.47 mm. Otherwise, the same pellicle case labels as in Example 1 were prepared. After printing a barcode on this label in the same manner as in Example 1, it was affixed to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 1. The labels adhered well. Furthermore, barcode scanning was performed on all three labels, and all were readable. Upon close examination with a magnifying glass, a slight blurring of the barcode printing was observed on one of the three labels due to the uneven surface of the label. However, this was minor, and as mentioned above, there were no issues with reading the barcode itself.

[0054] Comparing Example 1 and Example 8, it was found that the air release performance improved when the matrix mesh was coarser, as in Example 8. On the other hand, it was thought that the smoothness improved and the reading stability increased when the matrix mesh was finer, as in Example 1.

[0055] (Example 9) The matrix shape of the adhesive layer was set to 80 mesh. Furthermore, the width of the protrusions in the adhesive layer was set to 0.18 mm, and the width of one side of the recess was set to 0.14 mm. Otherwise, the same pellicle case labels as in Example 5 were prepared. After printing a barcode on this label in the same manner as in Example 5 (and Example 1), it was affixed to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 5 (and Example 1). Barcode scanning was successful, but several air bubbles, approximately 3-7mm in diameter, were found in the label application area. These bubbles could be easily removed by manually pressing them down.

[0056] Comparing Example 5 and Example 9, it can be seen that in Example 9, the matrix shape of the adhesive layer was finer than in Example 5. This suggests that during label application and heating at 80°C, some of the ventilation spaces in the matrix shape were crushed, preventing air bubbles from escaping. Thus, Example 5 yielded superior results in terms of air bubble release and other factors.

[0057] (Example 10) The adhesive strength of the adhesive layer was 1.0 N / 25 mm. Otherwise, the same pellicle case labels as in Example 4 were prepared. After printing a barcode on this label in the same manner as in Example 4 (and Example 1), it was affixed to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 4 (and Example 1). The barcode read successfully, but a small section of the label's corner was found to be curled up. This was easily repaired by manually pressing down on the curled area.

[0058] Comparing and considering Examples 4 and 10, it was concluded that an adhesive strength of approximately 1.2 N / 25 mm or more, as in Example 4, is more effective in preventing the label from peeling up.

[0059] (Example 11) The degree of penetration of the adhesive in the adhesive layer was 35. Otherwise, the same pellicle case labels as in Example 5 were prepared. After printing a barcode on this label in the same manner as in Example 5 (and Example 1), it was affixed to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 5 (and Example 1). Barcode scanning was successful, but several air bubbles, approximately 3-8 mm in diameter, were found in the label application area. These bubbles could be easily removed by manually pressing them down.

[0060] Comparing Example 5 and Example 11, it appears that in Example 11, the label adhesive was softer than in Example 5, which may have resulted in the matrix shape not being maintained as well, and air bubbles not being released. Thus, it was concluded that a penetration degree of around 30 or less, as in Example 5, is more effective in maintaining the matrix shape and preventing air bubbles from being released.

[0061] (Example 12) The thickness of the adhesive layer was set to 7 μm (thickness of the convex part: 7 μm, thickness of the concave part: 3 μm). Otherwise, the same pellicle case labels as in Example 7 were prepared. After printing a barcode on this label in the same manner as in Example 7 (and Example 1), it was affixed to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 7 (and Example 1). We confirmed that both barcode reading and label adhesion were good, but it was somewhat difficult to apply the label smoothly without any air bubbles. To make application easier, it was considered preferable to have a thickness of about 10 μm or more, as in Example 7.

[0062] (Comparative example) For use as labels for pellicle cases, we prepared label sheets with an area of ​​65mm x 60mm, a sheet thickness of 50μm, and an adhesive layer thickness of 35μm (uniform thickness across the entire surface). The label sheets were made of white PET film, and an acrylic adhesive was used for the adhesive layer. Furthermore, the acrylic adhesive used had a penetration degree of 15 and an adhesive strength of 3.8 N / 25 mm to polycarbonate. Thus, a label for a pellicle case (conventional product) identical to that in Example 1 was prepared, except that the adhesive layer was formed with a uniform thickness rather than a matrix-shaped uneven structure. After printing a barcode on this label in the same manner as in Example 1, it was affixed to the center of a precision-cleaned black polycarbonate pellicle case lid, and evaluated in the same manner as in Example 1.

[0063] After 7 days of storage, numerous air bubbles had formed, making it impossible to read the barcode properly. Furthermore, the only way to remove the air bubbles was to peel off the label. Furthermore, after heating at 80°C for two hours, the labels peeled off, requiring the labels to be reapplied.

[0064] [Table 1]

[0065] This specification includes the following embodiments: [1]: A label for a pellicle case that is attached to a pellicle case for storing pellicles, It comprises a label sheet and a label adhesive layer for attaching the label sheet to the pellicle case. The label adhesive layer is a label for a pellicle case in which the surface to be attached to the pellicle case has a matrix-shaped uneven structure. [2]: The label for pellicle cases according to [1], wherein the uneven structure of the label adhesive layer is such that the thickness of the raised portion is 10 μm or more and 60 μm or less. [3]: The label for pellicle cases according to [1] or [2] above, wherein the uneven structure of the label adhesive layer is such that the difference in thickness between the recessed and raised parts is 5 μm or more and 50 μm or less. [4]: A label for a pellicle case, any of the above [1] to [3], wherein the matrix shape of the label adhesive layer is 30 mesh or more and 70 mesh or less. [5]: A label for a pellicle case, any of the above [1] to [4], wherein the adhesive of the label adhesive layer is an acrylic adhesive. [6]: A label for a pellicle case according to any of [1] to [5] above, wherein the adhesive strength of the adhesive in the label adhesive layer is 1.2 N / 25 mm or more and 4.0 N / 25 mm or less relative to polycarbonate. [7]: A label for a pellicle case, any of the above [1] to [6], wherein the degree of penetration of the adhesive in the label adhesive layer is 5 or more and 30 or less. [8]: A label for a pellicle case, any of the above [1] to [7], wherein the label sheet is made of white PET.

[0066] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that has substantially the same technical idea as described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0067] 1, 1A...Label for pellicle case of the present invention, 2...Label sheet, 3...Label adhesive layer, 4...Surface for attaching to the pellicle case, 5...convex part, 6...concave part, B...bottom of the concave part, C... Pellicle case, W1: Width of the protruding part, W2: Width of one side of the concave part.

Claims

1. A label for a pellicle case that is attached to a pellicle case for storing pellicles, It comprises a label sheet and a label adhesive layer for attaching the label sheet to the pellicle case. The label adhesive layer is characterized in that the surface on which it is attached to the pellicle case has a matrix-shaped uneven structure.

2. The label for pellicle cases according to claim 1, characterized in that the uneven structure of the label adhesive layer has a thickness of 10 μm or more and 60 μm or less for the raised portion.

3. The label for pellicle cases according to claim 1, characterized in that the uneven structure of the label adhesive layer has a difference in thickness between the recessed and raised portions of 5 μm or more and 50 μm or less.

4. The label for pellicle cases according to claim 1, characterized in that the matrix shape of the label adhesive layer is 30 mesh or more and 70 mesh or less.

5. The label for pellicle cases according to claim 1, characterized in that the adhesive in the label adhesive layer is an acrylic adhesive.

6. The label for pellicle cases according to claim 1, characterized in that the adhesive strength of the adhesive in the label adhesive layer is 1.2 N / 25 mm or more and 4.0 N / 25 mm or less relative to polycarbonate.

7. The label for pellicle cases according to claim 1, characterized in that the degree of penetration of the adhesive in the label adhesive layer is 5 or more and 30 or less.

8. The label for pellicle cases according to claim 1, characterized in that the label sheet is made of white PET.

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