Pericle, exposure original plate, and exposure apparatus, and method for producing pericle and method for testing mask adhesive layer

Abstract

Provided is a pellicle having a frame 12 on which a pellicle film 11 is placed and an adhesive layer 13 for a mask placed on the frame 12, wherein when a water washing test is performed on the adhesive layer 13 which is in contact with a quartz mask 4 over a predetermined contact area A1, the removal rate of the adhesive layer 13 [(contact area A1 before water washing test – contact area A2 after water washing test) / (contact area A1 before water washing test)] is 80% or more.

Description

Technical Field

[0001] The present invention relates to a pellicle, a photomask blank, an exposure apparatus, a method for producing a pellicle, a method for testing an adhesive layer for a mask, and the like.

Background Art

[0002] In a lithography process for manufacturing electronic components, a pellicle may be used for dust prevention of a photomask. The pellicle has a frame on which a pellicle film is disposed and an adhesive layer for a mask disposed on the frame, and is attached to the photomask via the adhesive layer for a mask.

[0003] On the other hand, when the adhesive layer for a mask receives stray light during exposure, it is likely to react with the surface of the photomask, and as a result, the adhesion to the photomask is likely to increase. In this case, even when the pellicle is peeled off from the photomask, so-called "adhesive residue" may occur in which the adhesive remains on the photomask. In recent years, with the shortening of the wavelength of exposure light, the replacement frequency of photomasks has been increasing.

[0004] Here, a pellicle aimed at reducing adhesive residue has been proposed (see Patent Document 1). In Patent Document 1, it is proposed to control the content of the carboxylic acid-containing monomer unit in the adhesive layer for a mask to 0.9% by mass or less with respect to 100% by mass of the (meth)acrylic acid alkyl ester copolymer.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the prior art as described in Patent Document 1, it is difficult to completely remove the glue residue. Therefore, every time the photomask is replaced, an operation of removing the mask adhesive layer on the photomask has occurred. Assuming that a technology capable of further reducing the glue residue can be developed and used, it is assumed that the operation of removing the mask adhesive layer on the photomask will be performed as before as a preliminary operation every time the photomask is replaced.

[0007] Based on such a situation, in order to further improve the efficiency of the photomask replacement operation, it is necessary to focus on a different perspective from reducing the glue residue.

[0008] The present invention has been made in view of such a situation. The object of the present invention is To provide a pellicle that can further improve the efficiency of the photomask replacement operation by using a mask adhesive layer that is easily removed by water washing from a quartz mask, which is a typical quartz-made photomask. Another object of the present invention is to provide an exposure original plate, an exposure apparatus, a method for manufacturing a pellicle, a test method for a mask adhesive layer, etc. using the above-mentioned pellicle.

Means for Solving the Problems

[0009] Examples of embodiments according to the present invention are as follows. [1] A pellicle having a frame on which a pellicle film is disposed and a mask adhesive layer disposed on the frame, When a water washing test is performed on the adhesive layer that contacts a quartz mask with a predetermined contact area A1, the removal rate of the adhesive layer { (the contact area A1 before the water washing test - the contact area A2 after the water washing test) / (the contact area A1 before the water washing test)} is 80% or more. [2] The adhesive layer is The pellicle according to item 1, comprising a reaction product of a (meth)acrylic copolymer and a curing agent. [3] The pellicle according to item 2, wherein the curing agent is an isocyanate compound. [4] The pellicle according to item 2 or 3, wherein the ratio of the curing agent to the total amount of the (meth)acrylic copolymer is 0.10 to 3.00% by mass. [5] The pellicle according to any one of items 1 to 4, wherein the water washing test is performed by immersing the mask in a water tank for 10 minutes and then taking out the mask from the water tank. [6] The contact area A1 before the water washing test is The pellicle according to any one of items 1 to 5, which is the remaining area of the adhesive layer on the mask when the mask is irradiated with VUV (Vacuum UltraViolet) light from the back surface of the mask for 1 minute and then the pellicle is peeled off at the portion where the adhesive layer is attached to the mask. [7] The contact area A1 before the water washing test is The pellicle according to item 6, which is the remaining area when the VUV light is irradiated on the attachment portion for 1 minute and then the pellicle is peeled off. [8] The contact area A1 before the water washing test is At the portion where the adhesive layer is attached to the mask, VUV (Vacuum UltraViolet) light is irradiated from the back surface of the mask under the condition of an integrated radiation dose of 3.0 J / cm 2 The pellicle according to item 6, which is the remaining area of the adhesive layer on the mask when the pellicle is peeled off thereafter. [9] The pellicle according to any one of items 1 to 8, wherein the removal rate of the adhesive layer is 90% or more.

[10] The water washing test includes the following steps (A) to (D): (A) Immerse a quartz mask and the adhesive layer in contact with the quartz mask in water; (B) If, after 5 minutes from the start of immersion, the adhesive layer is in contact with the quartz mask in the water tank, wipe the adhesive layer with a finger; (C) After 10 minutes from the start of immersion, take out the quartz mask into the atmosphere; (D) If, in the atmosphere, the adhesive layer is in contact with the quartz mask, wipe the adhesive layer with a finger; The pellicle according to item 1 or 2, which is performed based on the above.

[11] An exposure original plate comprising a quartz mask and the pellicle according to any one of items 1 to 9 attached to the mask.

[12] A light source that emits VUV (Vacuum UltraViolet) light, The exposure original plate according to item 11, which is irradiated with the VUV light, An exposure apparatus comprising the above.

[13] A method for manufacturing a pellicle having a frame on which a pellicle film is disposed and a mask adhesive layer disposed on the frame, When a water washing test is performed on the adhesive layer that contacts the quartz mask with a predetermined contact area A1, the removal rate of the adhesive layer { (the contact area A1 before the water washing test - the contact area A2 after the water washing test) / (the contact area A1 before the water washing test)} is 80% or more. A method for manufacturing a pellicle.

[14] A test method for the mask adhesive layer of a pellicle having a frame on which a pellicle film is disposed and a mask adhesive layer disposed on the frame, A test method for the mask adhesive layer, which compares a value based on the removal rate of the adhesive layer { (the contact area A1 before the water washing test - the contact area A2 after the water washing test) / (the contact area A1 before the water washing test)} when a water washing test is performed on the adhesive layer that contacts the quartz mask with a predetermined contact area A1 with a predetermined threshold value.

[15] A peeling method for peeling the mask adhesive layer of a pellicle having a frame on which a pellicle film is disposed and a mask adhesive layer disposed on the frame from a quartz mask, A method for peeling an adhesive layer for a mask, comprising a step of irradiating a portion of the adhesive layer attached to the mask with VUV (Vacuum UltraViolet) light, and then a step of washing with water.

[16] In the step of irradiating the VUV light, The method for peeling an adhesive layer for a mask according to item 15, wherein the portion of the adhesive layer attached to the mask is irradiated with the VUV light from the back surface of the mask for 1 minute, and then the pellicle is peeled off.

[17] In the step of irradiating the VUV light, The portion of the adhesive layer attached to the mask is irradiated with the VUV light from the back surface of the mask under the condition of an integrated radiation dose of 3.0 J / cm 2 The method for peeling an adhesive layer for a mask according to item 15 or 16, and then the pellicle is peeled off. [Effect of the Invention]

[0010] According to the present invention, by focusing on a quartz mask typical as a photomask and using an adhesive layer for a mask that can be easily removed by washing with water from the quartz mask, it is possible to provide a pellicle that can further improve the efficiency of the photomask replacement work. Further, according to the present invention, it is possible to provide an exposure original plate, an exposure apparatus, a method for producing a pellicle, a test method for an adhesive layer for a mask, etc. using the above pellicle. [Brief Description of the Drawings]

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

[0012] Hereinafter, embodiments of the present invention (hereinafter referred to as "the present embodiment") will be described. In the present embodiment, the numerical range described using "~" includes the numerical values described before and after "~" within that range. In the present embodiment, the upper limit value or lower limit value described in a numerical range with a stepwise description can be replaced with the upper limit value or lower limit value of the numerical range in other stepwise descriptions. In the present embodiment, the upper limit value or lower limit value described in a certain numerical range can also be replaced with the value described in the examples. In the present embodiment, the term "step" includes not only an independent step but also cases where it cannot be clearly distinguished from other steps, as long as the function of the step is achieved. In each part of the drawings, the scale, shape, and length may be exaggerated for further clarity.

[0013] [Exposure Device and Exposure Master] FIG. 1 is a schematic diagram showing a configuration example of an exposure device 1 and an exposure master 2 according to the present embodiment. As shown in the figure, the exposure device 1 includes a light source 3 that emits light and an exposure master 2 irradiated with the light. Among them, the exposure master 2 includes a photomask 4 and a pellicle 5 attached to the photomask 4.

[0014] The light emitted from the light source 3 is VUV (Vacuum UltraViolet) light, and the photomask 4 is made of quartz. Hereinafter, a photomask configured to include quartz may sometimes be referred to as a quartz mask.

[0015] The pellicle 5 is attached to the photomask 4 so as to cover a circuit pattern (not shown) formed on the photomask 4. The pellicle 5 functions as a dust cover for the photomask 4. In the exposure device 1, the light (arrow in FIG. 1) emitted from the light source 3 passes through the circuit pattern of the photomask 4, and further passes through the pellicle film of the pellicle 5 and is guided to a photoresist (not shown) on the stage 6.

[0016] In the exposure apparatus 1 and the exposure original plate 2, since the pellicle 5 according to the present embodiment is provided, it is easy to remove the mask adhesive layer from the photomask 4, and thus, further efficiency improvement of the replacement work of the photomask 4 can be achieved.

[0017] [Pellicle] 〔Schematic Configuration〕 Figs. 2 and 3 are diagrams showing a configuration example of the pellicle 5 according to the present embodiment. Among these, Fig. 2(a) shows a configuration example when the pellicle 5 is attached to the photomask 4, and Fig. 2(b) shows a configuration example of the cross-section of the pellicle 5. Further, Fig. 3(a) shows a configuration example when the pellicle 5 is peeled from the photomask 4, and Fig. 3(b) shows a configuration example of the pellicle 5 (mask adhesive layer) after the water washing test. In Figs. 2 and 3, the attachment portion S1 of the pellicle 5 to the photomask 4 is indicated by a dotted line. As shown in the figure, the pellicle 5 has a frame 12 on which a pellicle film 11 is disposed, and a mask adhesive layer (hereinafter, may be simply referred to as "adhesive layer") 13 disposed on the frame 12. In the pellicle 5, the removal rate of the adhesive layer 13 when a water washing test is performed on the adhesive layer 13 that contacts the photomask 4 with a predetermined contact area A1 is 80% or more.

[0018] According to the above configuration, by the technical approach of using the adhesive layer 13 that is easy to remove from the photomask 4, further efficiency improvement of the replacement work of the photomask 4 can be achieved.

[0019] 〔Frame〕 The frame 12 is a member for supporting the pellicle film 11. The frame 12 includes a pair of sides 12A and a pair of sides 12B. The side 12A may be a long side, and the side 12B may be a short side. With these long sides 12A and short sides 12B, a rectangular outer shape is formed, and a rectangular opening Op is formed inside the outer shape.

[0020] Both the long side 12A and the short side 12B are substantially rectangular parallelepiped in shape. The long side 12A and the short side 12B each have four surfaces (one surface 12a, the other surface 12b opposite to the one surface 12a, the inner peripheral surface 12c, and the outer peripheral surface 12d opposite to the inner peripheral surface 12c). The one surface 12a has an area for attaching the pellicle film 11, and the other surface 12b has an area for forming the adhesive layer 13.

[0021] The length of the long side 12A is, for example, 50 mm or more, 80 mm or more, or 100 mm or more, and is also 200 mm or less, 180 mm or less, or 160 mm or less. The length of the short side 12B is 30 mm or more, 50 mm or more, or 80 mm or more, and is also 180 mm or less, 160 mm or less, or 140 mm or less. According to the lengths of the above long side 12A and / or short side 12B, it is easy to prevent the pellicle film 11 from being bent, and it is easy to surround the circuit pattern formed on the photomask 4.

[0022] However, the configuration (length, width, thickness, shape, etc.) of the frame 12 can be arbitrarily changed according to the configuration of the pellicle film 11, the size of the circuit pattern formed on the photomask 4, etc. The frame 12 may be integrally configured or may be configured to be divisible.

[0023] The frame 12 is aluminum; aluminum alloy (such as 5000 series, 6000 series, 7000 series, etc.); steel; stainless steel; magnesium alloy; ceramics such as silicon carbide (SiC), aluminum nitride (AlN), aluminum oxide (Al2O3); composite materials of ceramics and metals (such as Al - SiC, Al - AlN, Al - Al2O3, etc.); engineering plastics using polyethylene (PE), polyamide (PA), polycarbonate (PC), polyetheretherketone (PEEK), etc. Fiber composite materials such as glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP); or combinations thereof; etc. can be formed of known materials.

[0024] The inner peripheral surface 12c of the frame 12 may, if necessary, have an adhesive component for capturing foreign matter. Examples of the adhesive component here include acrylic-based, vinyl acetate-based, silicone-based, and rubber-based adhesives; silicone-based and fluorine-based greases; etc.

[0025] 〔Perforated film〕 The perforated film 11 is a thin film having transparency. The perforated film 11 covers the opening Op. The perforated film 11 is attached to one surface 12a of the frame 12 via a perforated film adhesive (not shown) in a state where a certain amount of tension is applied so as not to be excessively bent by its own weight.

[0026] The perforated film 11 can be formed of nitrocellulose, cellulose derivatives, fluoropolymers, etc. The thickness of the perforated film 11 is, for example, 10 μm or less from the viewpoints of the transparency of the light emitted from the light source, the light resistance to such light, the self-supporting property of the perforated film 11 itself, etc. Preferably, it is 5 μm or less, more preferably 1 μm or less.

[0027] 〔Protective film〕 The perforated film 5 may include a protective film 14 (liner) laminated on the adhesive layer 13. The protective film 14 protects the adhesive layer 13 during storage or transportation of the perforated film 5, and is peeled off from the adhesive layer 13 when the perforated film 5 is attached to the photomask 4.

[0028] The protective film 14 can be formed of a resin such as polyester, and its thickness is, for example, 30 to 200 μm. The protective film 14 may have a silicone layer or a fluorine layer on the surface in contact with the adhesive layer 13 for improving peelability.

[0029] [[MASK ADHESIVE LAYER]] [[REMOVAL RATE]] The adhesive layer 13 is a member for attaching the frame 12 to the photomask 4. The adhesive layer 13 can be disposed on the other surface 12b of the frame 12. Here, in the pellicle 5, when a water washing test is performed on the adhesive layer 13 that contacts the photomask 4 with the contact area A1, the removal rate of the adhesive layer 13 is 80% or more. The removal rate is calculated by the following formula: Removal rate = (Contact area A1 before water washing test - Contact area A2 after water washing test) / (Contact area A1 before water washing test) and is obtained by the formula above. For example, when approximately 90% of the adhesive layer 13 on the photomask 4 is removed by the water washing test, the removal rate is expected to be approximately 90%, at least 80% or more.

[0030] When the removal rate of the adhesive layer 13 is 80% or more, the removal operation of the adhesive layer 13 on the photomask 4 can be shortened and / or simplified, thereby reducing the labor required for the removal operation. When the removal rate is sufficiently large, even if a mask adhesive layer that is likely to leave glue and / or a lithography process under conditions where glue is likely to remain are employed, it is easy to remove the adhesive layer 13 from the photomask 4. From the above, an improvement in the efficiency of the photomask 4 replacement operation is expected. From the same perspective, the above removal rate is preferably 85% or more, 90% or more, 95% or more, or 98% or more. The above removal rate may be 100% or less than 100%.

[0031] In one aspect, the "adhesive layer that contacts the photomask with a predetermined contact area A1" is the adhesive layer 13 remaining on the photomask 4. After the adhesive layer 13 is attached to the photomask 4 (see Fig. 2(a)), when the adhesive layer 13 is peeled off from the photomask 4 (see Fig. 3(a)), the remaining area of the adhesive layer 13 remaining on the photomask 4 can be treated as the contact area A1. According to this, it is easy to calculate the above removal rate considering the actual lithography process.

[0032] In another aspect, the "adhesive layer that contacts the photomask with a predetermined contact area A1" is an adhesive layer for a mask formed on the photomask 4. When the adhesive layer for a mask is directly applied onto the photomask 4, the area of the adhesive layer can be treated as the contact area A1 (the contact area A1' shown in FIG. 4). According to this, it is easy to set the contact area A1 as a certain fixed value.

[0033] The contact area A1 may be approximately calculated visually in some cases, and may also be calculated in detail by image analysis of the photomask 4 in some cases.

[0034] The "water washing test" is a test in which water is applied to the photomask 4 to which the adhesive layer 13 adheres. The water washing test is performed by the method described in the examples.

[0035] The "contact area A2 after the water washing test" is the area of the adhesive layer 13 in contact with the photomask 4 after the above water washing test. The contact area A2 may be approximately calculated visually in some cases (see FIG. 3(b)), and may also be calculated in detail by image analysis of the photomask 4 in some cases.

[0036] <Residual area> The contact area A1 before the water washing test is preferably the residual area of the adhesive layer 13 on the photomask 4 when the back surface of the photomask 13 is irradiated with VUV light for 1 minute at the pasting portion S1 of the adhesive layer 13 to the photomask 4 and then the pellicle 5 is peeled off.

[0037] The "back surface of the photomask" corresponds to the surface of the photomask 4 in FIG. 2 that is opposite to the surface to which the adhesive layer 13 is attached. Using the exposure apparatus 1 as shown in FIG. 1, under normal environment and normal operation in accordance with the actual lithography process, irradiate with VUV light for 1 minute. Then, under normal environment and normal operation in accordance with the actual lithography process, peel the pellicle 5 from the photomask 4. By the above, "when irradiating with VUV light from the back surface of the photomask for 1 minute and then peeling the pellicle" is realized. Note that the peeling can be performed by using a known tensile tester to lift the pellicle 5 vertically with respect to the photomask 4 at a speed of 1 to 10 mm / min.

[0038] The "remaining area of the mask adhesive layer on the photomask" corresponds to the area of the adhesive layer 13 remaining on the photomask 4 after the above peeling. The remaining area is also understood as the so-called "adhesive residue area". This remaining area can be roughly calculated, for example, visually, and can also be calculated in detail by image analysis of the photomask 4.

[0039] The irradiation time of the VUV light is 1 minute. The longer the irradiation time of the VUV light, the easier it is to cure the adhesive layer 13. According to this, it is easy to calculate the above removal rate in consideration of the actual lithography process. In the pellicle 5 according to the present embodiment, even if the irradiation time of the VUV light is selected to be a short time of 1 minute, it is easy to calculate the above removal rate.

[0040] The thickness of the adhesive layer 13 may be, for example, 0.15 to 3.0 mm, and can be appropriately selected according to the field and / or application of the final product realized through the lithography process. When performing lithography to obtain a semiconductor device, the thickness of the adhesive layer 13 suitable for the photomask used in the lithography is, for example, 0.15 mm or more, 0.20 mm or more, or 0.25 mm or more, and 1.0 mm or less, 0.8 mm or less, or 0.7 mm or less. When performing lithography to obtain a liquid crystal device, the thickness of the adhesive layer 13 suitable for the photomask used in the lithography is, for example, 0.80 mm or more, 1.0 mm or more, or 1.2 mm or more, and 3.0 mm or less, 2.5 mm or less, or 2.0 mm or less.

[0041] The flatness of the adhesive layer 13 in the cross-sectional direction may be 1 μm or more, or 2 μm or more, and may also be 20 μm or less, 15 μm or less, or 13 μm or less. If the flatness of the adhesive layer 13 in the cross-sectional direction is 1 μm or more, even if air bubbles are entrapped when the pellicle 5 is attached to the photomask 4, it becomes easier to suitably secure a path for the air bubbles to escape. Also, if the flatness of the adhesive layer 13 in the cross-sectional direction is 20 μm or less, the load when attaching the pellicle 5 to the photomask 4 is likely to be evenly applied to the adhesive layer 13 and, consequently, to the photomask 4.

[0042] The "cross-sectional direction of the mask adhesive layer" corresponds to the thickness direction of the frame 12. The flatness of the adhesive layer 13 in the cross-sectional direction can be derived by the following method. For any plurality of points (for example, 10 points, 12 points, 15 points, or 20 points), check each cross-section of the adhesive layer 13 arranged on the frame 12. In each cross-section, obtain the difference (height difference) between the maximum thickness and the minimum thickness. Then, obtain the average value of the height differences obtained for the number of the above-mentioned plurality of points. Such an average value corresponds to the above-mentioned flatness.

[0043] The thickness of the adhesive layer 13, and thus the flatness, can be measured using a laser displacement meter. For the pellicle 5 with the protective film 14, the flatness may be measured after peeling off the protective film 14. If the flatness is not affected by the protective film 14, the flatness may also be measured with the protective film 14 attached.

[0044] <Method for Peeling Mask Adhesive Layer> Another aspect of this embodiment is a method for peeling the adhesive layer 13. Such a peeling method includes a step of irradiating the portion where the adhesive layer 13 is attached to the photomask 4 with VUV light, and a subsequent step of washing with water. Based on the above steps, the adhesive layer 13 can be suitably peeled from the photomask 4 by washing with water. Therefore, for example, compared with the case of using an acid for mask cleaning or strongly peeling off the mask adhesive layer from the photomask, the possibility of damaging the photomask 4 and the haze generation rate during exposure are less.

[0045] In the step of irradiating with VUV light, it is preferable to irradiate the portion where the adhesive layer is attached to the mask with VUV light from the back surface of the mask for 1 minute, and then peel off the pellicle. According to this, it becomes easier to suitably peel the adhesive layer 13 from the photomask 4 by washing with water.

[0046] Also, in the step of irradiating with VUV light, it is preferable to irradiate the portion where the adhesive layer is attached to the mask with VUV light from the back surface of the mask under the condition of an integrated radiation dose of 3.0 J / cm 2 and then peel off the pellicle. This also makes it easier to suitably peel the adhesive layer 13 from the photomask 4 by washing with water.

[0047] The adhesive layer 13 can include, for example, (A) component: a main agent having a specific functional group, and (B) component: a curing agent having reactivity with the specific functional group, and can include structures respectively derived from each of them. In other words, the adhesive layer 13 can be configured to contain a reaction product of the above component (A) and the above component (B). Various physical properties of the adhesive layer 13 can be controlled by the types and / or ratios, etc. of the above component (A) and the above component (B), and thus, the above removal rate can be controlled.

[0048] The adhesive layer 13 contains, for example, an acrylic copolymer. The acrylic copolymer is easy to control various physical properties, and the raw materials thereof are also easy to obtain.

[0049] The ratio of the component (A) to the total amount of the adhesive layer 13 is preferably 98.0% by mass or more, or 99.0% by mass or more, and is preferably 99.9% by mass or less, or 99.8% by mass or less. When the ratio of the component (A) is within the above range, it is easy to exhibit good adhesiveness of the adhesive layer 13 to the photomask 4, appropriate peelability of the adhesive layer 13 from the photomask 4, etc. Moreover, it is easy to remove the adhesive layer 13 from the photomask 4.

[0050] <(Component (A): Main agent)> The component (A) includes, for example, a (meth)acrylic copolymer, that is, a (meth)acrylate copolymer. In one aspect, the (meth)acrylate copolymer is a copolymer of a (meth)acrylate and a monomer having a specific functional group. Among them, a copolymer obtained by using a mixture in which the (meth)acrylate is 80 to 99% by mass and the monomer having a specific functional group is 1 to 20% by mass is preferable from the viewpoint of exhibiting appropriate adhesive force to the photomask 4.

[0051] The weight average molecular weight of the component (A) is, for example, 700,000 to 2,500,000. In this case, it is easy to control the cohesive force of the adhesive layer 13 and / or the adhesive force of the adhesive layer 13 to the photomask 4 to an appropriate magnitude. From the same viewpoint as above, the weight average molecular weight of the component (A) is 900,000 or more, or 1,050,000 or more, and is 2,000,000 or less, or 1,500,000 or less.

[0052] The weight average molecular weight of component (A) tends to increase, for example, when the monomer concentration is high, the amount of polymerization initiator is small, and the polymerization temperature is low during the polymerization reaction of its monomer raw materials. Generally, the greater the weight average molecular weight, the greater the cohesive force tends to be, and the greater the cohesive force, the greater the residual stress value tends to be.

[0053] Component (A) can be produced using known polymerization methods. Examples of such polymerization methods include radical polymerization, ionic polymerization, living polymerization, living radical polymerization, etc. In the polymerization, a polymerization initiator, a chain transfer agent, an emulsifier, etc. may be appropriately selected and used.

[0054] ((Meth)acrylate) In the (meth)acrylate, for example, the carbon number of its alkyl group is 1 to 14, and such an alkyl group may be linear or branched. However, from the viewpoint of reducing residue and good adhesiveness to the photomask 4, etc., the alkyl group preferably has 4 to 8 carbon atoms and is linear. The (meth)acrylate can be used alone or in combination of two or more.

[0055] Examples of the (meth)acrylate with a linear alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, etc.

[0056] Examples of the (meth)acrylate with a branched alkyl group include isopropyl (meth)acrylate, isobutyl (meth)acrylate, isopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, etc.

[0057] (Monomer having a specific functional group) Monomers having specific functional groups are copolymerizable with (meth)acrylate esters. Herein, the "specific functional group" refers to a functional group having reactivity with component (B), for example, a carboxyl group (-COOH) and / or a hydroxyl group (-OH). Monomers having specific functional groups can be used alone or in combination of two or more.

[0058] Examples of monomers having specific functional groups include carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, crotonic acid, etc.; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, etc. and the like.

[0059] The quartz photomask 4 has hydroxyl groups on its surface. When a reaction occurs between the hydroxyl groups in the photomask 4 and the carboxyl groups contained in the above carboxyl group-containing monomers in the adhesive layer 13, the bond between the photomask 4 and the adhesive layer 13 tends to become strong. Therefore, the ratio of the above carboxyl group-containing monomers to the total amount of component (A) is preferably 0.9% by mass or less, 0.5% by mass or less, or 0.3% by mass or less.

[0060] When the number of crosslinks due to the reaction between the hydroxyl groups contained in the hydroxyl group-containing monomers and component (B) increases per unit polymer length of the adhesive layer 13, the flexibility of the polymer is impaired, so the residual stress tends to increase. Also, when the number of hydroxyl groups contained in the hydroxyl group-containing monomers in component (A) increases, the number of residual hydroxyl groups after the reaction with component (B) increases, and the remaining hydroxyl groups are liable to be naturally oxidized or oxidized in the exposure environment, thereby making it easier to generate carboxyl groups. Therefore, the ratio of the above hydroxyl group-containing monomers to the total amount of component (A) is preferably 10% by mass or less, 4% by mass or less, or 2% by mass or less.

[0061] As the photomask 4, one having a chromium vapor deposition film formed on its surface may be used. In this case, the light emitted from the light source is blocked by the chromium vapor deposition film. Therefore, the reaction between the photomask 4 and the adhesive layer 13 is prevented from being caused by such light. On the other hand, by controlling the ratio of the carboxyl group-containing monomer to the total amount of the (A) component as described above, it is easy to effectively reduce the residue of the adhesive for the photomask 4 in which the chromium vapor deposition film is omitted. At the same time, it is easy to remove the adhesive layer 13 from the photomask 4.

[0062] <(Component (B): curing agent)> (B) component has reactivity with a specific functional group in the above (A) component. Examples of the (B) component include metal salts, metal alkoxides, aldehyde-based compounds, non-amino resin-based amino compounds, urea-based compounds, isocyanate compounds, epoxy compounds, metal chelate-based compounds, melamine-based compounds, aziridine compounds, and the like. Among them, an isocyanate compound or an epoxy compound is preferable, and an isocyanate compound is more preferable.

[0063] The ratio of the (B) component to the total amount of the (A) component is preferably 0.10 to 3.00% by mass. According to this, it is easy to remove the adhesive layer 13 from the photomask 4. From the same viewpoint, 0.130% by mass or more, or 0.150% by mass or more is more preferable, and 2.00% by mass or less, 1.20% by mass or less, or 1.00% by mass or less is more preferable.

[0064] Examples of the isocyanate compound include adduct type or isocyanurate type such as toluene diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and the like can be mentioned.

[0065] Examples of the polyfunctional epoxy compound include Examples include neopentyl glycol diglycidyl ether, polyethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, phthalic acid diglycidyl ester, dimer acid diglycidyl ester, triglycidyl isocyanurate, diglycerol triglycidyl ether, sorbitol tetraglycidyl ether, N, N, N', N'-tetraglycidyl m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl diaminodiphenylmethane, and the like.

[0066] <Other components> The adhesive layer 13 may contain known additives such as fillers, pigments, diluents, anti-aging agents, and UV stabilizers, as necessary. The additives can be used individually or in combination of two or more.

[0067] [Method for manufacturing a pellicle] The manufacturing method according to this embodiment is A method for manufacturing a pellicle 5 in which the removal rate of the adhesive layer 13 is 80% or more when a water washing test is performed on the adhesive layer 13 that contacts the photomask 4 with a predetermined contact area A1.

[0068] Such a manufacturing method can have, for example, the following steps. First step: A step of obtaining a precursor composition for the adhesive layer 13. Second step: A step of applying the obtained precursor composition to the frame 12. Third step: A step of drying the applied precursor composition to obtain the adhesive layer 13.

[0069] In the first step, component (A) and component (B) are mixed to obtain a precursor composition for the adhesive layer 13. Component (A) and / or component (B) may be mixed as they are, or may be mixed after being diluted in a predetermined solvent. The precursor composition may further contain a solvent from the viewpoint of controlling the coatability on the frame 12 and / or from the viewpoint of controlling the thickness of the resulting adhesive layer 13. Examples of these solvents include, but are not limited to, acetone, ethyl acetate, butyl acetate, toluene, and the like.

[0070] As described above, various physical properties of the adhesive layer 13 can be controlled by the types and / or ratios of component (A) and component (B), and thus the removal rate can be controlled.

[0071] In the second step, the obtained precursor composition is applied to the frame 12. In one aspect, in the second step, the precursor composition is applied to the other surface 12b of the frame 12. As the application method, a method using a dispenser is preferable. At this time, the viscosity of the precursor composition may be 1 P·s or more, or 2 P·s or more, and may also be 5 P·s or less, 4 P·s or less, or 3 P·s or less. The viscosity here is obtained, for example, by a B-type viscometer at 25°C.

[0072] In the third step, the applied precursor composition is dried to obtain the adhesive layer 13. This third step can further include the following steps. Third (1) step: Drying step. Third (2) step: Forming step.

[0073] In the third (1) step, the applied precursor composition is dried to reduce the solvent in the precursor composition. In the third (1) step, the dried precursor composition may be heated to a moldable degree. The heating time may be, for example, 50 to 10,000 seconds, and the heating temperature may be, for example, 50 to 200°C. The heat drying may be performed multiple times at different heating times or different temperatures.

[0074] In the third (2) step, the precursor composition is formed into a predetermined thickness and / or a predetermined width. In the third (2) step, the formed precursor composition may be further heated so that the curing reaction between the component (A) and the component (B) further proceeds.

[0075] The manufacturing method according to this embodiment may further include the following steps. Fourth step: A step of laminating a protective film 14 on the adhesive layer 13.

[0076] In the fourth step, the protective film 14 is laminated on the adhesive layer 13. In the fourth step, after laminating the protective film 14, the state may be maintained at room temperature (20 ± 3°C) for several days. Thereby, the adhesive force may be stabilized.

[0077] In addition, in the manufacturing method according to this embodiment, the attachment of the pellicle film 11 to the frame 12 may be performed before the first step, between the first step and the second step, between the second step and the third step, between the third step and the fourth step, or after the fourth step.

[0078] [Embodiment 2] [Test method for adhesive layer for mask] The test method according to this embodiment is a test method for the adhesive layer for a mask. In such a test method, a value based on the removal rate of the adhesive layer for a mask { (contact area A1 before the water washing test - contact area A2 after the water washing test) / (contact area A1 before the water washing test)} when a water washing test is performed on the adhesive layer for a mask that contacts a quartz mask with a predetermined contact area A1 is compared with a predetermined threshold value. According to such a method, the efficiency of the replacement operation of the quartz mask can be evaluated. In addition, the adhesive layer for a mask can be disposed on the frame 12 of the pellicle 5, and in one aspect, it can be disposed on the other surface 12b of the frame 12.

[0079] In the above test method, the value of the removal rate itself may be compared with a threshold value, or a value correlated with the removal rate may be compared with a threshold value. The threshold value can be determined as appropriate. When comparing the value of the removal rate itself with the threshold value, the threshold value is, for example, 80%. When the removal rate is 80% or more, further efficiency improvement of the mask replacement operation is expected.

[0080] In the above test method, the adhesion agent layer for mask on the quartz mask may or may not be irradiated with VUV light from the back surface of the mask at the attachment portion. When irradiating with VUV light, the irradiation time is, for example, 30 seconds to 5 minutes, or 30 seconds to 2 minutes, and in one aspect, it is 1 minute. The light irradiated from the back surface of the mask, and / or conditions such as the irradiation time can be appropriately selected under the conditions conforming to the actual lithography process. By assuming the normal environment and normal operation conforming to the actual lithography process and performing the above test, it is easy to evaluate the efficiency of the mask replacement operation in the actual lithography process.

[0081] In one aspect, the "adhesion agent layer for mask that contacts the quartz mask with a predetermined contact area A1" in the above test method may be the adhesion agent layer 13 remaining on the photomask 4 (that is, the adhesion agent layer 13 with glue remaining) described in Embodiment 1, FIGS. 2 and 3 above. The remaining area of the adhesion agent layer 13 remaining on the photomask 4 can be treated as the contact area A1.

[0082] FIGS. 4(a) and (b) are diagrams showing an example of another aspect of the present embodiment. In FIG. 4(b), the attachment portion SS of the adhesion agent layer for mask to the photomask 4 is indicated by a dotted line.

[0083] As shown in the figure, the "adhesion agent layer for mask that contacts the quartz mask with a predetermined contact area A1" in the above test method may be the adhesion agent layer 13a formed on the photomask 4. The area of the adhesion agent layer 13a when directly applying the adhesion agent layer 13a on the photomask 4 can be treated as the contact area A1 (the contact area A1' shown in FIG. 4(a)). Also in this embodiment, similar to the above-described embodiment, after performing the above water washing test, the area of the adhesive layer 13a in contact with the photomask 4 is treated as the contact area A2 (contact area A2' shown in FIG. 4(b)).

[0084] When directly applying the adhesive layer 13a onto the photomask 4, the steps of disposing the adhesive layer 13 on the frame 12, attaching the pellicle 5 to the photomask 4, and peeling the pellicle 5 from the photomask 4 can be omitted. Note that, as a method for directly applying the adhesive layer 13a onto the photomask 4, a method similar to the method of applying the adhesive layer 13 on the other surface 12b of the frame can be adopted.

[0085] The above is the description of this embodiment. This embodiment is not limited to the above-described aspects, and various modifications can be made and implemented within the scope of the gist thereof.

Example

[0086] Next, the present embodiment will be described more specifically by giving examples and comparative examples.

[0087] 〔Example 1〕 <Preparation of Adhesive Composition> First, ethyl acetate (30 parts by mass) and the raw materials shown in the table (raw materials for component (A)) were charged into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen inlet tube, and reacted at the reflux temperature for 8 hours under a nitrogen atmosphere. After the reaction was completed, butyl acetate (33 parts by mass) was added to obtain a solution of a (meth)acrylate copolymer (component (A)) having a nonvolatile content concentration of 37% by mass. To 100 parts by mass of the obtained solution, the raw materials shown in the table (component (B)) were added, and stirred and mixed to obtain an adhesive composition.

[0088] <Preparation of Pellicle> An adhesive composition prepared as described above was applied using a dispenser to the other surface of a frame made of an aluminum alloy (outer diameter 115 mm × 149 mm, inner diameter 111 mm × 145 mm, height 3.0 mm) with a pellicle film adhered to one surface. The applied adhesive composition was heated in two steps (step 1: 115 °C, 11 minutes; step 2: 150 °C, 5 minutes) to obtain an adhesive layer for mask (thickness 0.20 mm). Thereafter, a protective film made of polyester with a thickness of 100 μm having a silicone layer formed thereon was laminated on the adhesive layer for mask, and cured at 100 °C for 12 hours. From the above, the pellicle of Example 1 was produced.

[0089] 〔Other Examples〕and〔Comparative Examples〕 (A) The raw material for the component and (B) the raw material for the component were changed as shown in the table, and a pellicle was produced in the same manner as in the method of Example 1.

[0090] <Adhesive residue> The pellicles of the examples and comparative examples (for the pellicles with protective films, after peeling off the protective films) were attached to a photomask (size 6025, made of quartz) using a simple mounter with a load (5 Kgf, 60 seconds). Thereby, an exposure original plate having a photomask and a pellicle mounted on the photomask was obtained.

[0091] The portion of the adhesive layer for mask attached to the photomask was irradiated with VUV light from the back surface of the photomask for 1 minute, and then the pellicle was peeled off from the photomask. The peeling was performed by using a known tensile tester and pulling it up vertically with respect to the photomask at a speed of 5 mm / min. The photomask was observed visually and using a microscope, and the remaining area (contact area A1) of the adhesive layer for mask on the photomask was calculated. Note that the irradiation conditions of the VUV light are as follows. Light source: Xe Illuminance: 50 mW / cm 2 Integrated radiation dose: 3.0 J / cm 2

[0092] <Water washing test> A water washing test was conducted on the photomask with the mask adhesive layer remaining on the photomask according to the following methods and conditions. That is, the photomask with the mask adhesive layer remaining on the photomask was immersed in a water tank at room temperature for 10 minutes, and then taken out of the water tank. While the photomask was being immersed and after the photomask was taken out of the water tank, the adhesive layer adhering to the photomask was gently contacted with a finger or the palm of the hand, etc.

[0093] The specific method of the water washing test is as follows in steps (A) to (D): (A) Immerse a quartz mask and the adhesive layer in contact with the quartz mask in water; (B) After 5 minutes have elapsed since the start of immersion, if the adhesive layer is in contact with the quartz mask in the water tank, rub the adhesive layer with a finger; (C) After 10 minutes have elapsed since the start of immersion, take out the quartz mask into the atmosphere; (D) In the atmosphere, if the adhesive layer is in contact with the quartz mask, rub the adhesive layer with a finger; as follows.

[0094] In this water washing test, pure water is used as the water, and both the water temperature and the room temperature are adjusted to 24 ± 1°C. In steps (B) and (D), when the adhesive layer is in contact with the quartz mask, rub the adhesive layer directly 10 times with the pad of the finger.

[0095] <Removal rate> After the water washing test, the photomask was observed visually and using a microscope, and the area of the mask adhesive layer (contact area A2) on the photomask was calculated. Using the obtained contact area A2 and the above contact area A1, the removal rate was calculated. Then, the pellicles of the examples and comparative examples were evaluated according to the following criteria. A: Removal rate is 90% or more B: Removal rate is 80% or more and less than 90% C: Removal rate is less than 80%

[0096] <Efficiency of Photomask Replacement Work> As described above, by reducing the adhesive residue, the work of removing the mask adhesive layer remaining on the photomask can be shortened and / or simplified. Therefore, the pellicles of the examples and comparative examples were evaluated according to the following criteria. A: The "removal rate" was rated A or B, and the adhesive layer could be peeled off from the photomask without applying any special vibration to the photomask. B: The "removal rate" was rated A or B, and the adhesive layer could be peeled off from the photomask by applying some vibration to the photomask. C: The "removal rate" was rated C.

[0097]

Table 1

[0098] As confirmed from the table, the pellicles of the examples are excellent in "removal rate". By using the pellicles of the examples, further efficiency improvement of the photomask replacement work is expected.

Industrial Applicability

[0099] The present invention can be suitably applied to a lithography process for obtaining electronic components such as integrated circuits (ICs), large-scale integrated circuits (LSIs), and liquid crystal displays (LCDs). The present invention can be suitably applied to fields such as pellicles, photomasks, and exposure apparatuses, as well as methods for producing pellicles and test methods for mask adhesive layers.

Explanation of Signs

[0100] 1: Exposure apparatus 2: Photomask 3: Light source 4: Photomask (quartz mask) 5: Pellicle 6: Stage 11: Pellicle film 12: Frame 12A: Side (long side) 12B: Side (short side) 12a: One surface 12b: The other surface 12c: Inner peripheral surface 12d: Outer peripheral surface 13, 13a: Adhesive layer (mask adhesive layer) 14: Protective film Op: Opening A1 (A1’): Contact area before water washing test A2 (A2’): Contact area after water washing test

Claims

1. A pellicle having a frame on which a pellicle film is disposed and an adhesive layer for a mask disposed on the frame, wherein the adhesive layer contains a reaction product of a (meth)acrylic copolymer and a curing agent, the curing agent is an isocyanate compound, when a water washing test is performed on the adhesive layer that contacts a quartz mask with a predetermined contact area A1, the contact area A1 before the water washing test is the remaining area of the adhesive layer on the mask when the back surface of the mask is irradiated with VUV (Vacuum Ultraviolet) light for 1 minute and then the pellicle is peeled off at the portion where the adhesive layer is attached to the mask, a pellicle in which the removal rate of the adhesive layer { (the contact area A1 before the water washing test - the contact area A2 after the water washing test) / (the contact area A1 before the water washing test)} is 80% or more.

2. The pellicle according to claim 1, wherein the ratio of the curing agent to the total amount of the (meth)acrylic copolymer is 0.10 to 3.00% by mass.

3. The pellicle according to claim 1 or 2, wherein the water washing test is performed by immersing the mask in a water tank for 10 minutes and then taking out the mask from the water tank.

4. The contact area A1 before the water washing test is the remaining area when the VUV light is irradiated on the attachment portion for 1 minute and then the pellicle is peeled off, of the pellicle according to claim 1.

5. The contact area A1 before the water washing test is At the portion where the adhesive layer is attached to the mask, VUV (Vacuum Ultraviolet) light is integrally irradiated from the back surface of the mask under the condition of an integrated radiation dose of 3.0 J / cm ２ The pellicle according to claim 1, which is the remaining area of the adhesive layer on the mask when the pellicle is peeled off after irradiation.

6. The pellicle according to claim 1 or 2, wherein the removal rate of the adhesive layer is 90% or more.

7. The water washing test is based on the following steps (A) to (D): (A) Immersing a quartz mask and the adhesive layer in contact with the quartz mask in water; (B) After 5 minutes have elapsed since the start of immersion, if the adhesive layer is in contact with the quartz mask in the water tank, rubbing the adhesive layer with a finger; (C) After 10 minutes have elapsed since the start of immersion, taking out the quartz mask into the atmosphere; (D) If the adhesive layer is in contact with the quartz mask in the atmosphere, rubbing the adhesive layer with a finger; The pellicle according to claim 1 or 2, which is performed based on the above.

8. An exposure original plate comprising a quartz mask and the pellicle according to claim 1 or 2 mounted on the mask.

9. A light source that emits VUV (Vacuum Ultraviolet) light, The exposure original plate according to claim 8, which is irradiated with the VUV light, An exposure apparatus comprising the same.

10. A method for manufacturing a pellicle having a frame on which a pellicle film is disposed and an adhesive layer for a mask disposed on the frame, The adhesive layer contains a reaction product of a (meth)acrylic copolymer and a curing agent, The curing agent is an isocyanate compound, A method for manufacturing a pellicle, wherein when a water washing test is performed on the adhesive layer that contacts a quartz mask with a predetermined contact area A1, the removal rate of the adhesive layer { (the contact area A1 before the water washing test - the contact area A2 after the water washing test) / (the contact area A1 before the water washing test)} is 80% or more.

11. A test method for the adhesive layer for a mask of a pellicle having a frame on which a pellicle film is disposed and an adhesive layer for a mask disposed on the frame, A test method for the adhesive layer for a mask, wherein a value based on the removal rate of the adhesive layer { (the contact area A1 before the water washing test - the contact area A2 after the water washing test) / (the contact area A1 before the water washing test)} when a water washing test is performed on the adhesive layer that contacts a quartz mask with a predetermined contact area A1 is compared with a predetermined threshold value.

12. A peeling method for peeling the adhesive layer for a mask of a pellicle having a frame on which a pellicle film is disposed and an adhesive layer for a mask disposed on the frame from a quartz mask, The peeling method for the adhesive layer for a mask includes a step of irradiating the adhered portion of the adhesive layer to the mask with VUV (Vacuum Ultraviolet) light and a step of performing water washing thereafter.

13. In the step of irradiating the VUV light, The peeling method for the adhesive layer for a mask according to claim 12, wherein the adhered portion of the adhesive layer to the mask is irradiated with the VUV light from the back surface of the mask for 1 minute, and then the pellicle is peeled off.

14. In the step of irradiating the VUV light, The portion of the adhesive layer attached to the mask is irradiated with the VUV light from the back surface of the mask under the condition of an integrated radiation dose of 3.0 J / cm ２ , and then the pellicle is peeled off. The method for peeling an adhesive layer for a mask according to claim 12 or 13.

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