JP2012093517A - Pellicle frame body and pellicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pellicle frame body and a pellicle capable of reducing generation of haze even under irradiation with high-energy light and having superiority in a contamination inspection.SOLUTION: A pellicle frame body 2 is formed of an aluminum material into a frame shape. The aluminum material is formed with an anodic oxide film P that is anodized with at least one electrolyte selected from a group of oxalic acid, malonic acid, succinic acid, phosphoric acid and salt thereof. The material of the aluminum material includes Cu:0.5-3.0%, Mg:1.5-4.5%, and Zn:4.0-7.0%.

Description

  The present invention manufactures semiconductor devices and liquid crystal display devices such as IC (Integrated Circuit), LSI (Large Scale Integration), TFT LCD (Thin Film Transistor, Liquid Crystal Display), etc. The present invention relates to a pellicle frame body and a pellicle of a pellicle used for preventing foreign matter from adhering to a photomax and a reticle used in a lithography process.

  A manufacturing process of a thin film transistor (TFT), a color filter (CF), or the like constituting a semiconductor device such as an LSI or an ultra LSI or a liquid crystal display (LCD) includes a photolithography process using an exposure apparatus. At this time, a dust-proof means generally called a pellicle is used. This pellicle has a transparent polymer film (such as nitrocellulose, cellulose derivative, fluoropolymer, etc. having a thickness of about 10 μm or less on the upper edge surface of a frame with a thickness of about several millimeters having a shape matched to a photomask or a reticle. Optical thin film) is spread and bonded to prevent foreign matter from directly adhering to the photomask or reticle. Even if foreign matter adheres to the pellicle in the photolithography process, the foreign matter does not form an image on the wafer coated with the photoresist, so that the exposure pattern is prevented from being short-circuited or disconnected by the image of the foreign matter. The manufacturing yield of the process can be improved.

  For this reason, the pellicle maker cannot ship the pellicle itself with foreign matter attached. Therefore, during the pellicle manufacturing process, the pellicle manufacturer repeatedly inspects the foreign matter using equipment such as visual inspection and equipment (mainly visual inspection). The pellicle is inspected for foreign matter before shipment. Mask manufacturers and device manufacturers also use the pellicle to check for foreign matter on the pellicle before attaching it to the mask. do not use. Therefore, the ease of inspection of foreign matter has been sought from the past, and the pellicle frame is black as a countermeasure.

In recent years, with the high integration of semiconductor devices, drawing of a fine circuit pattern with a narrower line width is required, and KrF excimer laser (wavelength 248 mm) and ArF excimer laser (wavelength) are also used for exposure light used in the photolithography process. 193 mm), F ₂ excimer lasers (wavelength 157 nm), and the like. However, since these short-wavelength exposure light sources have high output, the energy of light is high, and there is a problem that the reaction product adheres to a photomask or the like as the exposure time elapses, causing haze. . Even in the case of a good quality state with no defects in post-manufacture inspection of photomasks and the like, haze is generated on the photomask and reticle as the exposure apparatus repeats excimer laser irradiation, and a good pattern transfer image is obtained. In some cases, the circuit of the semiconductor element is disconnected or short-circuited.

  The frame of the pellicle is generally made of an aluminum material, and an anodic oxide film is usually formed on the surface thereof. However, the electrolytic solution used for forming the anodized film contains an acidic component such as sulfuric acid, and when it remains in the formed film, it is detached in a photolithography process or the like, and the photomask or reticle is removed. It is generated as a gaseous substance in a closed space between the two. Then, haze is generated by causing a photochemical reaction with ammonia, cyanide compounds, hydrocarbon compounds and the like contained in the atmosphere.

  In view of the above problem, a method is known in which an acidic component is removed by performing ultrasonic cleaning in pure water after anodizing the pellicle frame (see, for example, Patent Document 1). There is also a method of forming a polymer film by electrodeposition coating instead of an anodized film, and a method of suppressing haze to the extent that it does not affect the photolithography process by individually specifying the content of acidic components It is known (see, for example, Patent Documents 2 and 3).

  In addition, as described in Patent Document 4, for example, by performing an acid immersion dissolution treatment at the time of anodizing treatment, the ratio of the pore diameter of the porous layer to the cell diameter is adjusted, and the pore diameter is increased to increase the pore diameter. There is also known a method that makes it easier to clean the ions and reduces ions related to haze.

  In addition, since the pattern miniaturization is progressing along with the shorter wavelength and higher energy of the exposure light in recent years, if the flatness of the mask is poor, the focus shift occurs at the time of exposure, and the accuracy of the pattern to be burned is deteriorated. A problem occurs. Therefore, the flatness of the mask is required to have higher accuracy than before. One of the factors that change the flatness of the mask is said to be the effect of the pellicle. Therefore, there is also a method for defining the flatness of the pellicle frame (see, for example, Patent Document 5).

JP 2006-184822 A JP 2007-333910 A JP 2007-225720 A JP 2010-113350 A JP 2008-256925 A

  The conventional haze problem described above has not been solved yet, and there is a demand for further reduction in the content of acidic components that are substances that cause haze generation. Therefore, we considered that the absolute ion content in the film can be reduced by making the film thickness of the anodized film thinner than before.

  However, when the coating described in Patent Document 4 is made thin by using the JIS A6000 system, which is an aluminum alloy that has been conventionally used, the color of the pellicle frame cannot be blackened and becomes blue. Turned out to be. When the color of the pellicle frame is blue, the foreign matter inspectability during the process is deteriorated, and the tactileness of the foreign matter inspectability during the process is increased. Furthermore, even if it takes a long time for inspection, the percentage of foreign matter that can be found is reduced compared to black or a color close to black (for example, dark blue or dark brown), so the pellicle can be assembled without removing the foreign matter completely. There is also a possibility that. In such a case, for example, if a foreign object is sandwiched between the mask adhesive body and the pellicle frame body, it will become an air path after being attached to the mask, and another foreign object will enter from there, or the foreign object may be peeled off. May lead to For this reason, there is a possibility that the foreign matter inspection property is lowered. Further, in order to prevent reflection of light from the frame body due to scattered light during exposure, it is desired to make the color black or a color close to black.

  The present invention has been made to solve the above-described problems, and provides a pellicle frame body and a pellicle that can reduce the generation of haze even under irradiation with high-energy light and are excellent in foreign matter inspection. For the purpose.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research, and as a result, by using an aluminum material containing a specific component and anodizing with a specific electrolytic solution, the haze can be improved as compared with the prior art. It has been found that it is possible to reduce the content of the acidic component that is the generation causative substance, and furthermore, the pellicle frame body has a color close to black (dark blue), and a pellicle frame body with good foreign matter inspection can be obtained. The present invention has been completed.

  That is, the pellicle frame according to the present invention is a pellicle frame that is formed into a frame shape with an aluminum material, and that stretches and supports an optical thin film covering the opening, and the aluminum material includes oxalic acid, malonic acid, and succinic acid. An anodized film that has been anodized with at least one electrolyte selected from the group consisting of acid, phosphoric acid, and salts thereof is formed on the surface, and Cu: 0.5-3 0.0%, Mg: 1.5-4.5%, Zn: 4.0-7.0%.

  The thickness of the anodized film formed by anodizing the aluminum material is 0.5 μm to 10 μm.

  In addition, heat treatment is performed at 150 ° C. to 350 ° C. before the anodizing treatment.

  In addition, a pellicle according to the present invention includes the above-described pellicle frame and a pellicle film that is stretched and supported so as to cover an opening of the pellicle frame.

  According to the present invention, generation of haze can be reduced even under irradiation with high-energy light, and excellent foreign matter inspection can be achieved.

1 is a perspective view showing a pellicle using a pellicle frame according to an embodiment of the present invention. It is the II-II sectional view taken on the line in FIG. It is a table | surface which shows an evaluation result.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  FIG. 1 is a perspective view showing a pellicle using a pellicle frame according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG. As shown in FIGS. 1 and 2, a pellicle 1 includes a pellicle frame (pellicle support frame) 2, a pellicle film (optical thin film body) 3 stretched and supported on the upper edge surface 2e of the pellicle frame 2, An adhesive body 10 applied to the lower edge surface 2f of the pellicle frame body 2 and a protective film F that adheres to the adhesive body 10 and protects the adhesive body 10 are provided.

The pellicle frame 2 is composed of a pair of opposed long sides (frame members) 2a and 2b and a pair of opposed short sides (frame members) 2c and 2d shorter than the long sides 2a and 2b. In the plan view, it has a rectangular shape. In the pellicle frame 2, the long side 2a and the long side 2b are formed to have the same length, and the short side 2c and the short side 2d are formed to have the same length. The pellicle frame 2 has a rectangular opening 4, and the long sides 2 a and 2 b and the short sides 2 c and 2 d form the periphery of the opening 4. The opening area of the opening 4 is preferably 18000 cm ² or more, more preferably 23000 cm ² or more and 35000 cm ² or less.

  The pair of long sides 2a and 2b is formed of a column member having a width of, for example, 9.0 mm, and the length thereof is, for example, 800 mm. The pair of short sides 2c and 2d is made of a column member having a width of, for example, 7.0 mm, and the length thereof is, for example, 480 mm. That is, the width of the short sides 2c and 2d in plan view (top view) is narrower than the width of the long sides 2a and 2b. The curvature of the corner 5 of the pellicle frame 2 is, for example, R = 2 mm. Grooves 7 are provided along the longitudinal direction (side direction) on the side surface 6 of the pellicle frame 2.

  The width of each side 2a to 2d of the pellicle frame 2 is preferably as thin as possible from the viewpoint of securing an exposure area. However, if the width is too small, the pellicle frame 2 is stretched by the tension of the pellicle film 3 when the pellicle film 3 is expanded. There is a risk that the problem of bending will occur. Since the width takes into account the rigidity with respect to the length of each side, each side 2a to 2d can be about 3 mm to 25 mm.

  Further, regarding the thickness of the pellicle frame body 2, the thinner the pellicle 1, the lighter and easier to handle the pellicle 1. However, if the pellicle film 3 is too thin, the pellicle frame body 2 will be bent by the tension of the pellicle film 3. Problems may arise. The thickness of the pellicle frame body 2 is preferably about 4.5 mm to 12 mm from the balance between the two sides according to the lengths of the sides 2a to 2d.

The pellicle film 3 is not particularly limited and a known one can be used. For example, inorganic substances such as quartz, nitrocellulose, polyethylene terephthalate, cellulose esters, fluorine-based polymers, polycarbonate, polymethyl methacrylate, and the like can be used. A polymer etc. can be illustrated. The pellicle film 3 may include an antireflection layer made of an inorganic material such as CaF ₂ or a polymer such as polystyrene or Teflon (registered trademark). The thickness of the pellicle film 3 is preferably 10 μm or less and 0.1 μm or more, for example. The pellicle film 3 is spread on the upper edge surface 2 e so as to cover the opening 4 of the pellicle frame 2, and is attached to and supported by the pellicle frame 2.

  As an adhesive for adhering the pellicle film 3 to the upper edge surface 2e of the pellicle frame 2, for example, a fluorine-based polymer such as an acrylic resin adhesive, an epoxy resin adhesive, a silicone resin adhesive, or a fluorine-containing silicone adhesive is used. be able to.

  The pressure-sensitive adhesive layer for sticking and supporting the pellicle film 3 may be a styrene ethylene butylene styrene, styrene ethylene propylene styrene, or olefin-based hot-melt pressure-sensitive adhesive, silicone-based pressure-sensitive adhesive, acrylic pressure-sensitive adhesive, or foam. The adhesive tape which made the base material can be used. The thickness of the pressure-sensitive adhesive layer is set within a range that does not exceed the distance between the pellicle film 3 and the photomask in which the sum of the thickness of the pellicle frame 2 and the thickness of the pressure-sensitive adhesive layer is defined. 0.01 mm or more is preferable.

  Further, as described above, the lower edge surface 2f of the pellicle frame body 2 is provided with the adhesive body 10 for mounting the pellicle 1 on a photomask or a reticle. As the adhesive body 10, an adhesive material alone or a material in which an adhesive material is applied on both sides of an elastic base material can be used. Examples of the pressure-sensitive adhesive body 10 include acrylic, rubber-based, vinyl-based, epoxy-based, and silicone-based adhesives, and examples of the highly elastic material serving as a base material include rubber and foam. Examples thereof include, but are not limited to, butyl rubber, foamed polyurethane and foamed polyethylene.

  Further, the pellicle frame 2 can collect foreign matter, use an inner wall adhesive or the like on the inner wall for light resistance, or coat the inner wall. Examples of the inner wall adhesive material include an acrylic resin, an acrylic adhesive material, a fluorine resin, and a fluorine adhesive material. Considering light resistance in particular, it is preferably a fluororesin, and specific examples include tetrafluoroethylene copolymer, hexafluoropropylene copolymer, vinylidene fluoride copolymer, etc. It is not limited.

  In addition, when a pellicle 1 is attached to the photomask, if there is a space inside the pressure-sensitive adhesive body 10, there is a possibility that foreign matter may stay in the space. Therefore, when applying the adhesive body 10 to the lower edge surface 2f of the pellicle frame body 2, it is necessary to consider that the adhesive body 10 is crushed and spread by the pressure applied when the pellicle 1 is attached to the photomask. It is preferable to apply to the inside of the opening 4 of the pellicle frame 2 so that the adhesive does not protrude into the opening 4 during pressure. Specifically, it is preferable to apply so that the space inside the adhesive body 10 is within 0.35 times the application width of the adhesive body 10. The application width of the pressure-sensitive adhesive body 10 is preferably 0.3 to 0.6 times the width of each side 2a to 2d of the pellicle frame 2, and is applied along each side 2a to 2d of the pellicle frame 2. It is preferable.

  As the protective film F for protecting the pressure-sensitive adhesive body 10, a film made of polyethylene terephthalate resin or polyethylene resin can be used. Moreover, according to the adhesive force of the adhesive body 10, you may apply | release a mold release agent, for example, a silicone type release agent, or a fluorine type release agent on the surface of a protective film. The thickness of the protective film is preferably, for example, 1 mm or less and 0.01 mm or more.

  Next, the pellicle frame body 2 will be described in more detail. The pellicle frame 2 is made of an aluminum material. An aluminum material consists of aluminum or an aluminum alloy, Cu: 0.5-3.0%, Mg: 1.5-4.5%, Zn: 4.0-7.0% as an essential component Contains. These elements are effective components for improving the strength, and if the amount is less than the lower limit, the strength may be insufficient. On the other hand, if the amount is more than the upper limit, the casting and hot workability of the material is lowered, making it difficult to manufacture. In some cases, the above content is preferable. The aluminum material is preferably JIS A7000, and more preferably JIS A7075 from the viewpoint of strength and flatness after surgery. In the present embodiment, aluminum is used even when the above components are included.

  An anodized film P is formed on the surface of the aluminum material by anodizing with an electrolytic solution other than sulfuric acid. For the electrolytic solution used for anodizing treatment other than sulfuric acid, for example, an electrolytic solution containing at least one polyvalent acid selected from the group consisting of oxalic acid, malonic acid, succinic acid, phosphoric acid, and salts thereof is used. Anodization treatment using an electrolytic solution containing a divalent acid using an aqueous solution of oxalic acid or an oxalate salt is particularly preferable. This is because it is necessary to perform anodization without using sulfuric acid which is the largest causative substance of haze. In addition, since electrolytes and the like may remain in the film, it is also preferable from the total amount of ions that reduce haze, and in the case of an aluminum material, corrosion resistance is slightly inferior, which is preferable from the viewpoint of corrosion resistance and wear resistance. .

Hereinafter, the case where an aqueous solution of oxalic acid or oxalate is used as the electrolytic solution will be described. However, the electrolytic solution is not limited to an aqueous solution of oxalic acid or oxalate. Examples of the oxalate include potassium hydrogen oxalate, potassium oxalate, sodium oxalate, and ammonium oxalate, preferably potassium hydrogen oxalate, potassium oxalate, and sodium oxalate. The concentration of the electrolyte solution, an oxalic acid radical (C 2 O 4 2-) is often in the range of 20~90g / L, preferably in that a 30 to 60 g / L. An appropriate electrolysis voltage can be obtained when the oxalate radical concentration is in the range of 20 g / L to 90 g / L.

  About the voltage of an anodizing process, it is good that it is 10-60V, Preferably it is 20-50V. If it is higher than 10 V, the strength of the resulting anodic oxide film P can be used sufficiently, and by making it lower than 60 V, a large surface area can be obtained in the porous layer formed in the film. Sufficient colorability can be obtained by the coloring treatment. The temperature of the electrolytic solution is preferably 15 to 40 ° C., and the treatment time for anodization is 2 to 60 minutes, preferably 5 to 20 minutes.

  And the conditions of these anodizing treatments are adjusted, and the film thickness of the obtained anodized film P is 0.5 to 10 μm, preferably 1.0 to 6.0 μm, and further 2.0 to 4.5 μm. Is desirable. If the thickness of the anodic oxide film P is larger than 0.5 μm, sufficient colorability can be obtained by the coloring treatment, and if it is smaller than 10 μm, the amount of acidic components taken into the film can be reduced to the extent that it does not cause haze. . In the case of anodizing using a JIS A6000 system that has been used in the past, if the film is thinned, a blue (bright color) frame is formed. Therefore, the film cannot be thinned from the viewpoint of foreign matter inspection. However, by using the aluminum material containing the specific component, it is possible to make the color close to black (dark color) with good foreign matter inspection property even if the film is thinned. Although the reason for the difference in coloring is not clear, it can be considered as follows.

  In the case of the aluminum material containing the specific component, it is preferable not to perform the acid immersion treatment. This is because the area of the porous layer in the film is enlarged by the acid immersion treatment and a large amount of dye for dyeing is taken in. However, during the acid immersion treatment, the second phase compound remaining in the film dissolves and light This is because the absorption / scattering of the light changes and the blackness may deteriorate.

  Further, by using an aqueous solution of oxalic acid or oxalate as described above, the amount of acid used is generally larger than that in the case of forming an anodic oxide film P using sulfuric acid (usually about 100 to 200 g / LL). Can be reduced. Moreover, since the obtained anodic oxide film P can have a Vickers hardness of about 150 to 500 Hv, it can suppress scratches and dust generation on the surface of the frame and is excellent in durability.

  In addition, after anodizing with an oxalic acid solution or the like of an aluminum material containing the above-mentioned specific component, an acid immersion treatment is performed to reduce ions. Cracking occurs. When such a microcrack occurs, it may cause a drop of a very small foreign substance that has entered the crack, or, in a high energy environment, an ion that may cause haze may be generated from the crack. Yes. Therefore, it becomes a serious problem for the pellicle, which is not preferable.

  Microcracks are intended for cracks with a width of 0.1 μm or more. As a method for evaluating the number of microcracks, a 10 cm (actual size 0.1 mm) straight line is drawn in a photograph in which the surface of the frame is magnified 1000 times with an electron microscope, and the number of cracks intersecting the straight line is calculated. As for the width of the crack, those that can be observed in the electron micrograph, that is, those having a crack width of 0.1 μm or more are counted.

  In general, microcracks are more likely to enter as the voltage during anodization is lower or a thick film is formed. One cause of microcracks is predicted to be that the coefficient of linear expansion differs between the oxide film and the base material of the aluminum alloy. Further, it is known that the anodized film P retains a compressive stress when the film is thin and a tensile stress when the film is thick. When exposed to a high temperature in the sealing step after anodizing treatment as in the present invention, if the film is thin, the compressive stress is relaxed and cracks do not occur, but if the film is thick, the tensile stress increases, If there is a defect, a crack will occur from that point. Moreover, since the low voltage film is soft and hard when it is high, it is highly sensitive to cracks.

  For this reason, it is considered that when the film thickness is thick, the residual compressive stress increases and the occurrence of cracks also increases. In the present embodiment, the film thickness is set to 0.5 to 10 μm to reduce ions, but as a result, it also leads to an effect of suppressing the occurrence of microcracks. Further, by setting the electrolytic voltage of the oxidation treatment to 10 V or higher (preferably 20 V or higher), it further leads to suppression of microcrack generation.

  Furthermore, it is preferable that the surface of the pellicle frame 2 is colored. The conditions for the coloring treatment are not particularly limited, and known methods can be employed. For example, a dyeing treatment with an organic dye or an inorganic dye, or a secondary electrolytic coloring treatment with a metal salt can be given. Preferably, the frame body is dyed after the anodizing treatment. The coloring treatment may be performed so-called blackening or a color close to black for the purpose of preventing exposure light scattering and the like and inspecting foreign matters. It is particularly preferable to use a dye that has a low content of an acidic component that causes haze. Moreover, you may perform a sealing process after a coloring process. The conditions for the sealing treatment are not particularly limited, and a known method can be adopted, but after the treatment, pure water washing is sufficiently performed. Preferably, the pure water temperature is 50 to 95 ° C., and cleaning is performed for 10 minutes to 24 hours. By performing this sealing treatment, even if an acidic component remains in the film, the outflow from the surface can be suppressed.

  In the present embodiment, it is preferable to perform a heat treatment (annealing treatment) of the aluminum material before the anodizing treatment. By performing the heat treatment in advance, the distortion of the aluminum material is removed, and the occurrence of cracks in the anodized film P formed by anodizing treatment can be suppressed. As for the specific processing conditions, since it is an aluminum material containing a specific component, it is a highly rigid base material whose crystal state does not change even at high temperatures. ° C.

  The heat treatment time is preferably 15 minutes to 90 minutes. Furthermore, in order to form a uniform anodic oxide film P, an etching process using acid or alkali may be performed as a pretreatment, and it is easy to detect when dust or the like adheres to the obtained frame. A blasting process or the like may be performed in advance. On the other hand, in order to increase the degree of cleaning, cleaning treatment such as pure water cleaning, hot water cleaning, and ultrasonic cleaning may be performed after the anodic oxidation processing, acid immersion dissolution processing, and further after coloring processing and sealing processing.

  Here, in the case of the conventional base material JIS A6000 series, when the heat treatment at the above-described temperature is applied, the crystal state changes, so that the high-temperature heat treatment cannot be applied. On the other hand, if it is an aluminum material containing the said specific component, the flatness of a frame will also be obtained from the balance of distortion removal and rigidity by performing the said heat processing.

The total elution amount of sulfate ion, nitrate ion, and organic acid ion (total amount of oxalate ion, formate ion, and acetate ion) is heated to 90 ° C. with 100 ml of pure water per 100 cm ² of surface area of pellicle frame 2. The elution concentration after immersion for 3 hours is preferably 50 μg or less, more preferably 25 μg or less, and even more preferably 15 μg or less.

On the surface of the pellicle frame body 2 that has undergone anodizing treatment, acid immersion dissolution treatment, and coloring treatment, the acid and alkali components contained in the aqueous solution and chemical solution used in these treatments and other treatments are either intact or ionized. It is thought that it has adhered as. Therefore, ions that are representative of these and that may affect the generation of haze, that is, sulfate ions (SO ₄ ²⁻ ) and nitrate ions (NO ³⁻ ) as inorganic acid ions, and oxalic acid as organic acid ions It is preferable that the amount of ions (C ₂ O ₄ ²⁻ ), formate ions (HCOO ⁻ ), and acetate ions (CH ₂ COO ⁻ ) is small.

Dissolution ions in the ion elution test, more particularly, organic acid ion (oxalate, formate ion, and acetate the total amount of ions) elution amount of, per surface area 100 cm ² of the pellicle frame 2 in pure water 100ml in The elution concentration is 35 μg or less, preferably 20 μg or less, more preferably 15 μg or less. Among organic acid ions, the concentration of oxalate ions is particularly 1 μg or less, preferably 0.8 μg or less, more preferably 0.3 μg or less. In addition, for inorganic acid ions, the elution amount of sulfate ions is 0.5 μg or less, preferably 0.1 μg or less, more preferably 0.05 μg or less in terms of the elution concentration in 100 ml of pure water per 100 cm ^{2 of the} frame surface area. Is good. Detection of eluted ions is performed by ion chromatographic analysis, and detailed measurement conditions will be described in the examples described later.

  As described above, in the pellicle 1, the pellicle film 3 is attached to the upper edge surface 2e of the pellicle frame 2, and the adhesive body 10 is provided on the lower edge surface 2f on the opposite side. The aluminum material forming the pellicle frame 2 has an anodized film P that has been anodized with at least one electrolyte selected from the group consisting of oxalic acid, malonic acid, succinic acid, phosphoric acid, and salts thereof. Formed on the surface, the aluminum material includes Cu: 0.5-3.0%, Mg: 1.5-4.5%, Zn: 4.0-7.0% Yes. With such a configuration, generation of haze can be reduced even under irradiation with high energy light, and the pellicle frame 2 excellent in foreign matter inspection can be obtained.

  Next, the present embodiment will be described more specifically with reference to examples and comparative examples. However, the present embodiment is not limited to the following examples unless it exceeds the gist.

[Example 1]
A JIS A7075 aluminum alloy material was cut, and cut and polished so that the outer dimensions of the frame were 149 mm × 122 mm × 5.8 mm and the frame thickness was 2 mm to prepare a frame material. Next, constant voltage electrolysis with an oxalic acid 50 g / L aqueous solution (C ₂ O ₄ ²⁻ : 48.9 g / L) at 30 ° C. and an electrolytic voltage of 40 V is performed for 10 minutes, and the frame material is anodized. did. After washing with pure water, the obtained anodic oxide film was confirmed with an eddy current film thickness meter (manufactured by Fisher Instruments Co., Ltd.), and the film thickness was 3.8 μm.

  The treated frame material was placed in an aqueous solution containing an organic dye (TAC411 manufactured by Okuno Pharmaceutical Co., Ltd.) at a concentration of 10 g / L, and immersed for 10 minutes at a temperature of 55 ° C. for dyeing. Thereafter, the frame material was put into an aqueous solution containing a sealing agent (Sealing X, manufactured by Hanami Chemical Co., Ltd.) at a concentration of 40 ml / L, and sealed by dipping at 90 ° C. for 20 minutes. Then, the pellicle frame was obtained by thoroughly washing with pure water. Here, the hue of the pellicle frame was visually inspected based on a conventional frame that has been blackened with alumite sulfate to determine whether the color of the support frame is light or dark. The result is shown in FIG. In FIG. 3, “<0.04” of “sulfate ion” indicates that it is below the lower limit of quantification.

Further, the pellicle frame obtained above was put in a polyethylene bag, sealed with 100 ml of pure water per 100 cm ^{2 of the} surface area of the frame, and immersed at 3O 0 C for 3 hours. The extracted water from which the elution components from the frame were extracted in this way was set at a cell temperature of 35 ° C. and a column (IonPacAS19) temperature of 35 ° C., and an ion chromatograph analyzer (ICS manufactured by Nippon Dionex Co., Ltd. -2100). From this extracted water, sulfate ion, nitrate ion, and organic acid ion (oxalate ion, formate ion and acetate ion) were detected. The results are shown in FIG.

  Furthermore, in a photograph in which the surface of another pellicle frame obtained under the conditions of Example 1 was magnified 1000 times with an electron microscope, a 10 cm straight line was drawn, and the number of cracks having a width of 0.1 μm or more intersecting the straight line was obtained. Asked. The result is shown in FIG.

Further, an amorphous fluoropolymer having a thickness of 0.8 μm is stretched as an optical thin film on one side of another pellicle frame obtained under the conditions of Example 1, and an acrylic-based polymer is applied to the opposite end of the frame. An adhesive body made of an adhesive body was provided to give a test pellicle. Then, this test pellicle was affixed to a quartz glass 6-inch photomask substrate on which a Cr test pattern was formed (reticle: washed under conditions where the concentration of the surface residual acid component was 1 ppb or less). Subsequently, the exposure intensity on the reticle surface was 0.7 mJ / cm ² / pulse with an ArF excimer laser, and irradiation was performed at a repetition rate of 200 Hz with a dose of 10,000 J / cm ² . After irradiation, the photomask was observed with a laser particle inspection device to check for the occurrence of haze or particles. The results are shown in FIG.

[Example 2]
The same frame material prepared in Example 1 was heat-treated at 280 ° C. for 30 minutes in the air prior to the anodizing treatment. Next, a pellicle frame and a pellicle were prepared in the same manner as in Example 1 except that the electrolysis time in the anodic oxidation treatment was 20 minutes. The items shown in FIG. 3 were evaluated in the same manner as in Example 1.

[Comparative Example 1]
A pellicle frame and a pellicle were prepared in the same manner as in Example 1 except that JIS A6061 aluminum alloy was used. The items shown in FIG. 3 were evaluated in the same manner as in Example 1.

[Comparative Example 2]
Using JIS A6061 aluminum alloy, a frame material on which an anodized film is formed in the same manner as in Example 1 is put into a separately prepared aqueous solution containing 50 g / L of oxalic acid, and acid immersion treatment is performed at a temperature of 30 ° C. for 30 minutes. A pellicle frame and a pellicle were prepared in the same manner as in Example 1 except for the above. The items shown in FIG. 3 were evaluated in the same manner as in Example 1.

[Comparative Example 3]
A pellicle frame and a pellicle were prepared in the same manner as in Example 1 except that the acid dipping treatment was performed in the same manner as in Comparative Example 2. However, the evaluation was stopped because many cracks occurred and the frame material could not be used.

  DESCRIPTION OF SYMBOLS 1 ... Pellicle, 2 ... Pellicle frame body, 3 ... Pellicle film (optical thin film body), 4 ... Opening part, P ... Anodized film.

Claims (4)

A pellicle frame body that is formed in a frame shape with an aluminum material and that stretches and supports an optical thin film body that covers the opening,
The aluminum material has an anodized film that is anodized with at least one electrolyte selected from the group consisting of oxalic acid, malonic acid, succinic acid, phosphoric acid, and salts thereof formed on the surface,
The aluminum material includes a pellicle frame including Cu: 0.5 to 3.0%, Mg: 1.5 to 4.5%, and Zn: 4.0 to 7.0%.   2. The pellicle frame according to claim 1, wherein the anodized film formed by anodizing the aluminum material has a thickness of 0.5 μm to 10 μm.   The pellicle frame according to claim 1 or 2, wherein a heat treatment is performed at 150 ° C to 350 ° C before the anodizing treatment. A pellicle frame according to any one of claims 1 to 3,
And a pellicle film stretched and supported so as to cover an opening of the pellicle frame.

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