Patent Application
20070292775
The pellicle of the present invention comprises an aluminum alloy pellicle frame having a polymer coating provided on the surface, and a pellicle film stretched over the pellicle frame.
A pellicle equipped with a pellicle frame formed by providing an anodized coating on the surface of an aluminum alloy has been used conventionally. With regard to this pellicle frame, an acid such as sulfuric acid, an organic acid (oxalic acid, acetic acid, etc.), or nitric acid, or a salt thereof that has been incorporated into the anodized coating during formation of the coating, dyeing, sealing, or surface etching, etc. desorbs from the interior of the frame during irradiation with UV light (i rays or g rays, KrF laser, ArF laser, F2 laser, etc.) in a lithographic step, exposure, or photomask storage, is generated as a gaseous material in a closed space formed between the pellicle and the photomask, and undergoes a photochemical reaction with ammonia, a cyan compound, or another hydrocarbon compound, etc. present in the environment under UV light during exposure or separately generated and supplied from the pellicle member, etc., thereby generating the cloudiness called haze, represented by ammonium sulfate, etc., or generating microparticles.
In the present invention, by coating the surface of a pellicle frame with a polymer so as to provide a polymer coating, it is possible to obtain a pellicle frame that reduces the generation of the acids released from the pellicle frame when it is used.
The present invention is explained below in further detail.
As shown in
In this case, the dimensions of these pellicle components are similar to those of a normal pellicle, for example, a semiconductor pellicle for lithography, a pellicle for a lithographic step of large liquid crystal display panel production, etc., and the materials of the components may be known materials, as described above.
The type of pellicle film is not particularly limited and, for example, an amorphous fluorine polymer, etc. that has conventionally been used for an excimer laser is used. Examples of the amorphous fluorine polymer include Cytop (product name, manufactured by Asahi Glass Co. Ltd.) and Teflon (Registered Trademark) AF (product name, manufactured by DuPont). These polymers may be used by dissolving them in a solvent as necessary when preparing the pellicle film, and may be dissolved as appropriate in, for example, a fluorine-based solvent.
With regard to the base material of the pellicle frame used in the present invention, a conventionally used aluminum alloy material, and preferably a JIS A7075, JIS A6061, or JIS A5052 material, is used, but it is not particularly limited as long as it is an aluminum alloy and the strength as a pellicle frame is guaranteed. The surface of the pellicle frame is preferably roughened by sandblasting or chemical abrasion prior to providing a polymer coating. In the present invention, a method for roughening the surface of the frame may employ a conventionally known method. It is preferable to employ a method for roughening the surface involving blasting the aluminum alloy material surface with stainless steel, carborundum, glass beads, etc., and further by chemically abrading with NaOH, etc.
The polymer coating on the surface of the pellicle frame may be provided by various methods, and in general spray coating, electrostatic coating, electrodeposition coating, etc. can be cited as examples. In the present invention, it is preferable to provide a polymer coating by electrodeposition coating.
With regard to the electrodeposition coating, either a thermosetting resin or a UV curing resin may be used. It is also possible to employ either anionic electrodeposition coating or cationic electrodeposition coating for the resins. In the present invention, since UV resistance is required, it is preferable to employ anionic electrodeposition coating of a thermosetting resin in terms of coating stability, appearance, and strength.
The surface of the polymer coating is preferably matte-finished for the purpose of suppressing reflection. Furthermore, in order to suppress the generation of organic outgas from the polymer coating, the thickness of the electrodeposition-coated polymer coating is optimized and, moreover, conditions for baking after the electrodeposition coating are set so that, compared with conventional conditions, the temperature is higher and the time is longer for completion.
In accordance with a polymer coating being provided, unlike an anodized coating obtained by a conventional anodization method, it becomes possible to eliminate the inclusion and release of sulfate ion, nitrate ion, and organic acid. Since the polymer coating may be provided by coating without using sulfuric acid, nitric acid, an organic acid, etc. at all, either as a starting material or in the process, it is possible to simplify a washing step, etc., which has been necessary in order to decrease the conventional problems of sulfate ion, nitrate ion, and organic acid.
Techniques for electrodeposition coating (electrodeposition) are known to a person skilled in the art. For example, reference may be made to 1) S. Tamehiro, ‘Denchakutoso (Electrodeposition Coating)’ (The Nikkan Kogyo Shimbun Ltd., 1969), and 2) ‘Kobunshi Daijiten’ (Polymer Dictionary) (Maruzen, 1994) ‘Toso/Denchaku’ section (Coating/Electrodeposition) and references therein. In electrodeposition coating, resin particle ions dispersed in water are attracted by the surface of an electrode material having the opposite sign and are deposited, thus forming a polymer coating.
In the present invention, for the electrodeposition coating, a method involving anionic electrodeposition coating, in which the material to be coated is the anode, is preferred to a method involving cationic electrodeposition coating, in which the material to be coated is the cathode, since the amount of gas generated is smaller and there is less possibility of defects such as pinholes occurring in the coated film.
In the pellicle of the present invention, the polymer coating provided on the pellicle frame covers various types, such as an epoxy resin, an acrylic resin, an aminoacrylic resin, or a polyester resin, but it is preferable to form the polymer coating from a thermosetting resin rather than a thermoplastic resin. Examples of the thermosetting resin are primarily acrylic resins. After a thermosetting coating is electrodeposition coated, the coating may be thermally cured.
Furthermore, the polymer coating is preferably a matte black electrodeposition-coated film, using a matte paint colored with a black pigment.
Prior to electrodeposition coating, it is preferable to subject the aluminum alloy frame to surface roughening by sandblasting or surface etching by means of an alkali solution.
The thickness of the electrodeposition-coated polymer coating is preferably 3 to 30 μm, more preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.
Coating equipment and a paint solution for electrodeposition coating used for these purposes may be purchased as commercial products from several Japanese companies and used. For example, an electrodeposition paint commercially available as Elecoat from Shimizu Co., Ltd. may be used. ‘Elecoat Frosty W-2’ and ‘Elecoat Frosty ST Satiner’ are matte type thermosetting anionic electrodeposition paints, and may preferably be used in the present invention.
When the polymer coating is a matte black electrodeposition-coated film, the emissivity is preferably 0.80 to 0.99. The ‘emissivity’ referred to here means a value obtained from P1/P, which is the ratio of the energy P1 radiated from a body to the total radiated energy P with a black body (an ideal body that absorbs all wavelengths incident on the surface and neither reflects nor transmits) as a reference, and is a value measured using a TSS-5X radiometer manufactured by Japan Sensor Corporation.
With regard to the pellicle of the present invention, the amounts of various types of anions leaching from the pellicle frame provided with the polymer coating by the polymer coating method are small.
Specifically, when immersed in pure water at 25° C. for 168 hours, it is preferable for the amount of sulfate ion leaching per pellicle frame weight to be 1.0 ppm or less, for nitrate ion to be 0.5 ppm or less, and for the total of organic acid ions such as oxalic acid and formic acid to be 1.0 ppm or less. These anions are quantitatively analyzed by an ion chromatograph. Detailed measurement conditions are as described in Examples.
With regard to the pellicle of the present invention, it is preferable for the amount of organic outgas generated from the pellicle frame when stored at 130° C. for 10 minutes to be 10.0 ppm or less per pellicle frame weight. Quantitative measurement is carried out by a GC-MS system. Detailed conditions for analysis are as described in Examples.
The anodized coating obtained by anodization, which has conventionally been applied to a pellicle frame, has marked surface irregularities due to its structure, is susceptible to cracking, etc., and easily allows foreign particles, etc. to become attached thereto, which are relatively difficult to remove by washing. The arrangement of the present invention, in which a polymer coating is provided, has the advantage that since the surface is smooth with few irregularities and is free from cracking, etc., attached particles can easily be removed.
The dust filter used in the present invention may be used in order to prevent particles from entering a space protected by affixing the pellicle, and this dust filter is not particularly limited in terms of shape, number, or location as long as it can be provided in the above-mentioned vent section. Examples of filter materials include resins (PTFE, nylon 66, etc.), metals (316L stainless steel, etc.), and ceramics (alumina, aluminum nitride, etc.). It is also preferable for the dust filter to be equipped on its exterior with a chemical filter for adsorbing or decomposing environmental chemical materials.
The adhesive for adhering the pellicle film may employ a conventionally used adhesive; examples thereof include an acrylic resin adhesive, an epoxy resin adhesive, a silicon resin adhesive, and a fluorine-based polymer such as a fluorine-containing silicon adhesive, and among them a fluorine-based polymer is suitable. Specific examples of the fluorine-based polymer include the fluorine-based polymer CT69 (product name, manufactured by Asahi Glass Co. Ltd.).
As adhesives for affixing the reticle, double-sided pressure-sensitive tape, a silicon resin pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, etc. can be cited.
The pellicle of the present invention may be produced by a normal method in which a pellicle film is stretched over an upper end face of a pellicle frame via an adhesive layer for adhering the pellicle film; an adhesive layer for affixing a reticle is normally formed on a lower end face of the pellicle frame, and a release layer is detachably affixed to a lower end face of the adhesive layer for affixing the reticle. Here, the adhesive layer for affixing the pellicle film formed on the upper end face of the pellicle frame may be formed by applying it to the upper end face of the pellicle frame after diluting it with a solvent as necessary, followed by heat drying and curing. In this case, as a method for applying the adhesive, a method involving brushing, spraying, an auto dispenser, etc. is employed.
The release layer for protecting the reticle adhesive that can be used in the present invention is not particularly limited in terms of material. Examples thereof include PET, PTFE, PFA, PE, PC, vinyl chloride, and PP.
Examples are described below.
First, as a pellicle frame, a frame was prepared using an A7075-T651 aluminum alloy so that the frame outer dimensions were 149 mm×122 mm×5.8 mm and the frame thickness was 2 mm. A vent having a diameter of 0.5 mm was provided in the middle on one side face of the frame.
After the surface of the frame was washed, the surface was roughened by subjecting it to a surface treatment for 1 minute employing a sandblasting machine using glass beads with a discharge pressure of 1.5 kg/cm2. Subsequently, the surface was etched by immersing it in an alkaline solution and then washed with water. After rinsing with pure water, it was subjected to electrodeposition coating with an Elecoat Frosty W-2 solution adjusted to 25° C. (Shimizu Co., Ltd; thermosetting anionic type, matte type; black paint) so that the coating thickness would be 5 μm (since the coating thickness depended on the condition of the solution, a dummy frame was fed in advance, and the voltage and time for the electrodeposition step were determined each time based on actual measurement. This applies below.) After shower-rinsing with pure water, a heat treatment was carried out in an oven at 200° C. for 30 minutes. The emissivity was 0.93.
One of the finished pellicle frames was cut into several pieces. They were placed in a polyethylene container, 100 mL of pure water was added thereto, the container was sealed, and immersion was carried out for 168 hours. Subsequently, the extracting water into which components had leached from the frame was analyzed using an ion chromatograph (Model 2050i, Dionex Corporation) and a Dionex lonPac ASA4A-SC column. The impurities detected in this extracting water were: sulfate ion not detected, nitrate ion not detected, chlorine ion 0.1 ppm, and organic acid (total amount of oxalic acid, formic acid, and acetic acid) 0.1 ppm.
Several frame pieces similarly cut were placed in a glass bottle, sampled using a head space sampler (Turbo Matrix HS, Perkin Elmer Japan Co., Ltd.) under conditions of 180° C. for 30 minutes, and subjected to a GC-MS analysis using a GC-MS system (QP-5050A, Shimadzu Corporation) and an HP-5 column (film thickness 0.25 μm, inner diameter 0.25 mm, length 30 m). From the results, the total amount of organic outgas was 3.5 ppm relative to the weight of the frame.
Subsequently, an inner face of this frame was coated with a 3 μm thick silicon-based pressure-sensitive adhesive by means of a spray coater.
Furthermore, the above-mentioned vent was equipped with a filter made from a PTFE material and having 99.9999% dust filtration for a size of 0.1 μm to 3.0 μm, a width of 9.5 mm, a height of 2.5 mm, and a thickness of 300 μm. The filter had a structure in which there was a chemical filter outside the dust filter.
A solution having a concentration of 8% was prepared by dissolving Teflon (registered trademark) AF1600 (product name, DuPont, USA) in the fluorine-based solvent Fluorinert FC-75 (product name, 3M, USA). A mirror-polished silicon substrate face having a diameter of 300 mm and a thickness of 600 μm was coated with this solution using a spin coater, thus forming a 0.8 μm thick transparent film. A frame having outer dimensions of 200 mm×200 mm×5 mm wide and a thickness of 5 mm was adhered to the film using the epoxy-based adhesive Araldite Rapid (product name, Showa Highpolymer Co., Ltd.) and it was peeled off.
One end face of the aluminum alloy frame prepared above was coated with a silicon-based pressure-sensitive adhesive, heated at 150° C. for 10 minutes, dried, and cured. The other end face of this aluminum alloy frame was coated with the fluorine-based polymer Polymer CTX (product name, Asahi Glass Co. Ltd.) diluted with the fluorine-based solvent CT-Solve 180 (product name, Asahi Glass Co. Ltd.), heated at 100° C. for 10 minutes, dried, and cured. A liner made of PET was prepared, and bonded to a reticle adhesive by means of a liner-affixing system having an image processing positioning mechanism equipped with a CCD camera. Subsequently, it was brought into intimate contact with the surface of the prepared Teflon (registered trademark) AF1600 film, and the frame and the film were then fusion bonded by heating the frame by means of an IR lamp. The two frames were mounted on a fixing jig with the adhesion face of the pellicle frame upward, and fixed so that their relative positions were not displaced. Subsequently, the frame outside the pellicle frame was pulled up and fixed, and a tension of 0.5 g/cm was applied to a film portion outside the pellicle frame.
Subsequently, unwanted film sections outside the pellicle frame were cut and removed using a tube-type dispenser on a cutter mounted on a SCARA robot while moving the cutter along the periphery of the adhesive section of the pellicle frame and dropping Fluorinert FC-75 (product name, DuPont) at 10 μL per minute.
The completed pellicle was affixed to a 6 inch photomask substrate made of quartz glass with a Cr test pattern formed thereon, which had been washed so that the concentration of residual surface acid components was 1 ppb or less. Subsequently, this was mounted on an NSR S306C ArF excimer laser scanner (product name, Nikon Corporation), and irradiated at a reticle face exposure strength of 0.02 mJ/cm2/pulse and a repetition frequency of 4000 Hz up to an exposure of 500 J/cm2.
When the irradiated 6 inch photomask was examined by means of a laser foreign matter detector, there was no haze and no foreign matter in either the test pattern section or the glass section.
In the same manner as in Example 1, as a pellicle frame, a frame was prepared using an A7075-T651 aluminum alloy so that the frame outer dimensions were 149 mm×122 mm×5.8 mm and the frame thickness was 2 mm. A vent having a diameter of 0.5 mm was provided in the middle on one side face of the frame.
After the surface of the pellicle frame was washed, the surface was roughened by subjecting it to a surface treatment for 1 minute employing a sandblasting machine using glass beads with a discharge pressure of 1.5 kg/cm2. Subsequently, the surface was etched by immersing it in an alkaline solution and then washed with water. After rinsing with pure water, it was subjected to electrodeposition coating with an Elecoat Frosty W-2 solution adjusted to. 25° C. (Shimizu Co., Ltd) so that the coating thickness would be 18 μm (since the coating depended on the condition of the solution, a dummy frame was fed in advance, and the voltage and time for the electrodeposition step were determined each time based on actual measurement.) After shower-rinsing with pure water, a heat treatment was carried out in an oven at 200° C. for 30 minutes.
When analysis was carried out in the same manner as in Example 1, the impurities detected were: sulfate ion not detected, nitrate ion not detected, chlorine ion 0.1 ppm, and organic acid (total amount of oxalic acid, formic acid, and acetic acid) 0.1 ppm.
Several frame pieces similarly cut were placed in a glass bottle, sampled using a head space sampler (Turbo Matrix HS, Perkin Elmer Japan Co., Ltd.) under conditions of 180° C. for 30 minutes, and subjected to a GC-MS analysis using a GC-MS system (QP-5050A, Shimadzu Corporation) and an HP-5 column (film thickness 0.25 μm, inner diameter 0.25 mm, length 30 m). From the results, the total amount of organic outgas was 9.3 ppm relative to the weight of the frame.
Furthermore, an inner face of this frame was coated with a 3 μm thick silicon-based pressure-sensitive adhesive by means of a spray coater. Subsequently, the above-mentioned vent was equipped with a filter made from a PTFE material and having 99.9999% dust filtration for a size of 0.1 μm to 3.0 μm, a width of 9.5 mm, a height of 2.5 mm, and a thickness of 300 μm. The filter had a structure in which there was a chemical filter outside the dust filter. A solution having a concentration of 8% was prepared by dissolving Teflon (registered trademark) AF1600 (product name, DuPont, USA) in the fluorine-based solvent Fluorinert FC-75 (product name, 3M, USA). A mirror-polished silicon substrate face having a diameter of 300 mm and a thickness of 600 μm was coated with this solution using a spin coater, thus forming a 0.8 μm thick transparent film.
Subsequently, a frame having outer dimensions of 200 mm×200 mm×5 mm wide and a thickness of 5 mm was adhered to the film using the epoxy-based adhesive Araldite Rapid (product name, Showa Highpolymer Co., Ltd.) and it was peeled off.
One end face of the aluminum alloy frame prepared above was coated with a silicon-based pressure-sensitive adhesive, heated at 150° C. for 10 minutes, dried, and cured. The other end face of this aluminum alloy frame was coated with the fluorine-based polymer Polymer CTX (product name, Asahi Glass Co. Ltd.) diluted with the fluorine-based solvent CT-Solve 180 (product name, Asahi Glass Co. Ltd.), heated at 100° C. for 10 minutes, dried, and cured. A liner made of PET was prepared, and bonded to a reticle adhesive by means of a liner-affixing system having an image processing positioning mechanism equipped with a CCD camera. Subsequently, it was brought into intimate contact with the surface of the prepared Teflon (registered trademark) AF1600 film, and the frame and the film were then fusion bonded by heating the frame by means of an IR lamp. The two frames were mounted on a fixing jig with the adhesion face of the pellicle frame upward, and fixed so that their relative positions were not displaced. Subsequently, the frame outside the pellicle frame was pulled up and fixed, and a tension of 0.5 g/cm was applied to a film portion outside the pellicle frame.
Subsequently, unwanted film sections outside the pellicle frame were cut and removed using a tube-type dispenser on a cutter mounted on a SCARA robot while moving the cutter along the periphery of the adhesive section of the pellicle frame and dropping Fluorinert FC-75 (product name, DuPont) at 10 μL per minute.
The completed pellicle was affixed to a 6 inch photomask substrate made of quartz glass with a Cr test pattern formed thereon, which had been washed so that the concentration of residual surface acid components was 1 ppb or less. Subsequently, this was mounted on an NSR S306C ArF excimer laser scanner (product name, Nikon Corporation), and irradiated at a reticle face exposure strength of 0.02 mJ/cm2/pulse and a repetition frequency of 4000 Hz up to an exposure of 500 J/cm2.
When the irradiated 6 inch photomask was examined by means of a laser foreign matter detector, there was no haze and no foreign matter in either the test pattern section or the glass section.
In the same manner as in Example 1, as a pellicle frame, a frame was prepared using an A7075-T651 aluminum alloy so that the frame outer dimensions were 149 mm×122 mm×5.8 mm and the frame thickness was 2 mm. A vent having a diameter of 0.5 mm was provided in the middle on one side face of the frame.
After the surface of the frame was washed, the surface was roughened by subjecting it to a surface treatment for 1 minute employing a sandblasting machine using glass beads with a discharge pressure of 1.5 kg/cm2. Subsequently, the surface was etched by immersing it in an alkaline solution and then washed with water. After rinsing with pure water, it was subjected to electrodeposition coating with an Elecoat Frosty W-2 solution adjusted to 25° C. (Shimizu Co., Ltd) so that the coating thickness would be 3 μm. After shower-rinsing with pure water, a heat treatment was carried out in an oven at 200° C. for 30 minutes.
When analysis was carried out in the same manner as in Example 1, the impurities detected were: sulfate ion not detected, nitrate ion not detected, chlorine ion 0.1 ppm, and organic acid (total amount of oxalic acid, formic acid, and acetic acid) 0.1 ppm.
Several frame pieces similarly cut were placed in a glass bottle, sampled using a head space sampler (Turbo Matrix HS, Perkin Elmer Japan Co., Ltd.) under conditions of 180° C. for 30 minutes, and subjected to a GC-MS analysis using a GC-MS system (QP-5050A, Shimadzu Corporation) and an HP-5 column (film thickness 0.25 μm, inner diameter 0.25 mm, length 30 m). From the results, the total amount of organic outgas was 1.8 ppm relative to the weight of the frame.
Subsequently, an inner face of this frame was coated with a 3 μm thick silicon-based pressure-sensitive adhesive by means of a spray coater.
Furthermore, the above-mentioned vent was equipped with a filter made from a PTFE material and having 99.9999% dust filtration for a size of 0.1 μm to 3.0 μm, a width of 9.5 mm, a height of 2.5 mm, and a thickness of 300 μm. The filter had a structure in which there was a chemical filter outside the dust filter.
A solution having a concentration of 8% was prepared by dissolving Teflon (registered trademark) AF1600 (product name, DuPont, USA) in the fluorine-based solvent Fluorinert FC-75 (product name, 3M, USA).
A mirror-polished silicon substrate face having a diameter of 300 mm and a thickness of 600 μm was coated with this solution using a spin coater, thus forming a 0.8 μm thick transparent film.
Subsequently, a frame having outer dimensions of 200 mm×200 mm×5 mm wide and a thickness of 5 mm was adhered to the film using the epoxy-based adhesive Araldite Rapid (product name, Showa Highpolymer Co., Ltd.) and it was peeled off.
One end face of the aluminum alloy frame prepared above was coated with a silicon-based pressure-sensitive adhesive, heated at 150° C. for 10 minutes, dried, and cured. The other end face_of this aluminum alloy frame was coated with the fluorine-based polymer Polymer CTX (product name, Asahi Glass Co. Ltd.) diluted with the fluorine-based solvent CT-Solve 180 (product name, Asahi Glass Co. Ltd.), heated at 100° C. for 10 minutes, dried, and cured. A liner made of PET was prepared, and bonded to a reticle adhesive by means of a liner-affixing system having an image processing positioning mechanism equipped with a CCD camera. Subsequently, it was brought into intimate contact with the surface of the prepared Teflon (registered trademark) AF1600 film, and the frame and the film were then fusion bonded by heating the frame by means of an IR lamp. The two frames were mounted on a fixing jig with the adhesion face of the pellicle frame upward, and fixed so that their relative positions were not displaced. Subsequently, the frame outside the pellicle frame was pulled up and fixed, and a tension of 0.5 g/cm was applied to a film portion outside the pellicle frame.
Subsequently, unwanted film sections outside the pellicle frame were cut and removed using a tube-type dispenser on a cutter mounted on a SCARA robot while moving the cutter along the periphery of the adhesive section of the pellicle frame and dropping Fluorinert FC-75 (product name, DuPont) at 10 μL per minute.
The completed pellicle was affixed to a 6 inch photomask substrate made of quartz glass with a Cr test pattern formed thereon, which had been washed so that the concentration of residual surface acid components was 1 ppb or less. Subsequently, this was mounted on an NSR S306C ArF excimer laser scanner (product name, Nikon Corporation), and irradiated at a reticle face exposure strength of 0.02 mJ/cm2/pulse and a repetition frequency of 4000 Hz up to an exposure of 500 J/cm2.
When the irradiated 6 inch photomask was examined by means of a laser foreign matter detector, there was no haze and no foreign matter in either the test pattern section or the glass section.
However, since a frame inner wall of the completed pellicle had uneven color and noticeable bright points due to pin holes, which were hard to differentiate from foreign matter and contamination on the inner wall, it was necessary to improve the pellicle appearance.
In the same manner as in Example 1, as a pellicle frame, a frame was prepared using an A7075-T651 aluminum alloy so that the frame outer dimensions were 149 mm×122 mm×5.8 mm and the frame thickness was 2 mm. A vent having a diameter of 0.5 mm was provided in the middle on one side face of the frame.
After the surface of the frame was washed, the surface was roughened by subjecting it to a surface treatment for 1 minute employing a sandblasting machine using glass beads with a discharge pressure of 1.5 kg/cm2. Subsequently, the surface was etched by immersing it in an alkaline solution and then washed with water. After rinsing with pure water, it was subjected to electrodeposition coating with an Elecoat Frosty W-2 solution adjusted to 25° C. (Shimizu Co., Ltd.) so that the coating thickness would be 23 μm. After shower-rinsing with pure water, a heat treatment was carried out in an oven at 200° C. for 30 minutes.
One of the finished pellicle frames was cut into several pieces. They were placed in a polyethylene container, 100 mL of pure water was added thereto, the container was sealed, and immersion was carried out for 168 hours. Subsequently, the extracting water into which components had leached from the frame was analyzed using an ion chromatograph (Model 2050i, Dionex Corporation) and a Dionex lonPac ASA4A-SC column. The impurities detected in this extracting water were: sulfate ion not detected, nitrate ion not detected, chlorine ion 0.1 ppm, and organic acid (total amount of oxalic acid, formic acid, and acetic acid) 0.1 ppm.
Several frame pieces similarly cut were placed in a glass bottle, sampled using a head space sampler (Turbo Matrix HS, Perkin Elmer Japan Co., Ltd.) under conditions of 180° C. for 30 minutes, and subjected to a GC-MS analysis using a GC-MS system (QP-5050A, Shimadzu Corporation) and an HP-5 column (film thickness 0.25 μm, inner diameter 0.25 mm, length 30 m). From the results, the total amount of organic outgas was 18.0 ppm relative to the weight of the frame.
Subsequently, an inner face of this frame was coated with a 3 μm thick silicon-based pressure-sensitive adhesive by means of a spray coater.
Subsequently, the above-mentioned vent was equipped with a filter made from a PTFE material and having 99.9999% dust filtration for a size of 0.1 μm to 3.0 μm, a width of 9.5 mm, a height of 2.5 mm, and a thickness of 300 μm. The filter had a structure in which there was a chemical filter outside the dust filter. Subsequently, a solution having a concentration of 8% was prepared by dissolving Teflon (registered trademark) AF1600 (product name, DuPont, USA) in the fluorine-based solvent Fluorinert FC-75 (product name, 3M, USA).
A mirror-polished silicon substrate face having a diameter of 300 mm and a thickness of 600 μm was then coated with this solution using a spin coater thus forming a 0.8 μm thick transparent film.
A frame having outer dimensions of 200 mm×200 mm×5 mm wide and a thickness of 5 mm was then adhered to the film using the epoxy-based adhesive Araldite Rapid (product name, Showa Highpolymer Co., Ltd.) and it was peeled off.
Subsequently, one end face of the aluminum alloy frame prepared above was coated with a silicon-based pressure-sensitive adhesive, heated at 150° C. for 10 minutes, dried, and cured. The other end face of this aluminum alloy frame was coated with the fluorine-based polymer Polymer CTX (product name, Asahi Glass Co. Ltd.) diluted with the fluorine-based solvent CT-Solve 180 (product name, Asahi Glass Co. Ltd.), heated at 100° C. for 10 minutes, dried, and cured. A liner made of PET was prepared, and bonded to a reticle adhesive by means of a liner-affixing system having an image processing positioning mechanism equipped with a CCD camera. Subsequently, it was brought into intimate contact with the surface of the prepared Teflon (registered trademark) AF1600 film, and the frame and the film were then fusion bonded by heating the frame by means of an IR lamp. The two frames were mounted on a fixing jig with the adhesion face of the pellicle frame upward, and fixed so that their relative positions were not displaced. Subsequently, the frame outside the pellicle frame was pulled up and fixed, and a tension of 0.5 g/cm was applied to a film portion outside the pellicle frame.
Subsequently, unwanted film sections outside the pellicle frame were cut and removed using a tube-type dispenser on a cutter mounted on a SCARA robot while moving the cutter along the periphery of the adhesive section of the pellicle frame and dropping Fluorinert FC-75 (product name, DuPont) at 10 μL per minute.
The completed pellicle was affixed to a 6 inch photomask substrate made of quartz glass with a Cr test pattern formed thereon, which had been washed so that the concentration of residual surface acid components was 1 ppb or less. Subsequently, this was mounted on an NSR S306C ArF excimer laser scanner (product name, Nikon Corporation), and irradiated at a reticle face exposure strength of 0.02 mJ/cm2/pulse and a repetition frequency of 4000 Hz up to an exposure of 500 J/cm2.
When the irradiated 6 inch photomask was examined by means of a laser foreign matter detector, there was no haze and no foreign matter in either the test pattern section or the glass section, but a white haze was observed on the inside of the film on the periphery of the pellicle frame. When the cloudy section was analyzed by means of a laser Raman spectroscope, it was found to be a hydrocarbon-based material.
First, as a pellicle frame, a frame was prepared using an A7075-T651 aluminum alloy so that the frame outer dimensions were 149 mm×122 mm×5.8 mm and the frame thickness was 2 mm. A vent having a diameter of 0.5 mm was provided in the middle on one side face of the frame.
After the surface thereof was washed, the surface was roughened by subjecting it to a surface treatment for 1 minute employing a sandblasting machine using glass beads with a discharge pressure of 1.5 kg/cm2. Subsequently, this was washed in a NaOH treatment bath for 10 sec, and anodization was then carried out at a formation voltage of 10 V (1.3 A) in a 14% aqueous solution of sulfuric acid. Subsequently, a black oxide coating was formed on the surface by black staining and sealing treatments. When the average coating thickness was measured, it was found to be 12 μm. After this, it was washed for 5 minutes by the use of ultrapure water and an ultrasonic washing system in combination.
One of the finished pellicle frames was cut into several pieces. They were placed in a polyethylene container, 100 mL of pure water was added thereto, the container was sealed, and immersion was carried out for 168 hours. Subsequently, the extracting water into which components had leached from the frame was analyzed using an ion chromatograph (Model 2050i, Dionex Corporation) and a Dionex IonPac ASA4A-SC column. The impurities detected in this extracting water were: sulfate ion 4.1 ppm, nitrate ion 0.6 ppm, chlorine ion 1.0 ppm, and organic acid (total amount of oxalic acid, formic acid, and acetic acid) 1.1 ppm.
Several frame pieces similarly cut were placed in a glass bottle, sampled using a head space sampler (Turbo Matrix HS, Perkin Elmer Japan Co., Ltd.) under conditions of 180° C. for 30 minutes, and subjected to a GC-MS analysis using a GC-MS system (QP-5050A, Shimadzu Corporation) and an HP-5 column (film thickness 0.25 μm, inner diameter 0.25 mm, length 30 m). From the results, the total amount of organic outgas was 0.4 ppm relative to the weight of the frame.
Subsequently, an inner face of this frame was coated with a 3 μm thick silicon-based pressure-sensitive adhesive by means of a spray coater.
Subsequently, the above-mentioned vent was equipped with a filter made from a PTFE material and having 99.9999% dust filtration for a size of 0.1 μm to 3.0 μm, a width of 9.5 mm, a height of 2.5 mm, and a thickness of 300 μm. The filter had a structure in which there was a chemical filter outside the dust filter. Subsequently, a solution having a concentration of 8% was prepared by dissolving Teflon (registered trademark) AF1600 (product name, DuPont, USA) in the fluorine-based solvent Fluorinert FC-75 (product name, 3M, USA).
A mirror-polished silicon substrate face having a diameter of 300 mm and a thickness of 600 μm was then coated with this solution using a spin coater, thus forming a 0.8 μm thick transparent film.
A frame having outer dimensions of 200 mm×200 mm×5 mm wide and a thickness of 5 mm was then adhered to the film using the epoxy-based adhesive Araldite Rapid (product name, Showa Highpolymer Co., Ltd.) and it was peeled off.
Subsequently, one end face of the aluminum alloy frame prepared above was coated with a silicon-based pressure-sensitive adhesive, heated at 150° C. for 10 minutes, dried, and cured. The other end face of this aluminum alloy frame was coated with the fluorine-based polymer Polymer CTX (product name, Asahi Glass Co. Ltd.) diluted with the fluorine-based solvent CT-Solve 180 (product name, Asahi Glass Co. Ltd.), heated at 100° C. for 10 minutes, dried, and cured. A liner made of PET was prepared, and bonded to a reticle adhesive by means of a liner-affixing system having an image processing positioning mechanism equipped with a CCD camera. Subsequently, it was brought into intimate contact with the surface of the prepared Teflon (registered trademark) AF1600 film, and the frame and the film were then fusion bonded by heating the frame by means of an IR lamp. The two frames were mounted on a fixing jig with the adhesion face of the pellicle frame upward, and fixed so that their relative positions were not displaced. Subsequently, the frame outside the pellicle frame was pulled up and fixed, and a tension of 0.5 g/cm was applied to a film portion outside the pellicle frame.
Subsequently, unwanted film sections outside the pellicle frame were cut and removed using a tube-type dispenser on a cutter mounted on a SCARA robot while moving the cutter along the periphery of the adhesive section of the pellicle frame and dropping Fluorinert FC-75 (product name, DuPont) at 10 μL per minute.
The completed pellicle was affixed to a 6 inch photomask substrate made of quartz glass with a Cr test pattern formed thereon, which had been washed so that the concentration of residual surface acid components was 1 ppb or less. Subsequently, this was mounted on an NSR S306C ArF excimer laser scanner (product name, Nikon Corporation), and irradiated at a reticle face exposure strength of 0.02 mJ/cm2/pulse and a repetition frequency of 4000 Hz up to an exposure of 500 J/cm2.
When the irradiated 6 inch photomask was examined by means of a laser foreign matter detector, there was no haze and no foreign matter in the test pattern section, but haze was observed in the glass section. When this was analyzed by means of a laser Raman spectroscope, it was found to be ammonium sulfate.
The above-mentioned Examples and Comparative Example are summarized in Table 1.
Detection limits for sulfate ion and nitrate ion were 0.1 ppm or less.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-164175 | Jun 2006 | JP | national |
