Patent Document

[0001]    This patent application claims priority from a Japanese patent application No. 2000-383205 filed on Dec. 18, 2000, the contents of which are incorporated herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a pellicle, a photomask, a pellicle frame, and a method for manufacturing a pellicle. More particularly, the present invention relates to a pellicle, which is used for protecting a reticle from attachment of a foreign matter. A reticle is used for a lithography process for manufacturing a semiconductor device such as an LSI (Large-Scale Integrated) circuit, a VLSI (Very Large-Scale Integrated) circuit, or an LCD (Liquid Crystal Display).  
           [0004]    2. Description of the Related Art  
           [0005]    To manufacture a semiconductor device such as an LSI circuit, a VLSI circuit, or an LCD by a lithography process, a light is irradiated to a semiconductor wafer through a reticle, on which a circuit pattern to be transcribed onto the wafer is formed. A reticle is a photomask used for a stepper. If foreign matter is attached to the reticle, this foreign matter absorbs or reflects the light, and thus the pattern transcribed onto the wafer may deform. Also, the shape of the edge of the pattern may deform. Therefore, the size, the quality, and the outward appearance of the pattern transcribed on the wafer deteriorate. Thus, the performance or the yield factor of a semiconductor device and LCD manufactured from this wafer decrease.  
           [0006]    Because of the above-mentioned reason, the lithography process described-above is performed inside a clean room. However, even inside the clean room, it is difficult to always maintain the reticle in a normal condition, that is, the condition where the reticle is free from attachment of foreign matter. Thus, usually, a pellicle that protects the reticle from foreign matter is adhered to the surface of the reticle. A pellicle is transparent so that a light used for exposure can transmit through the pellicle onto the reticle.  
           [0007]    By using a pellicle, the foreign matter does not attach to the surface of the reticle but attaches to the surface of the pellicle. Therefore, if the light is focused on the pattern of the reticle during the lithography process, the foreign matter, which attaches to the pellicle, does not influence the transcription of the pattern onto the wafer.  
           [0008]    [0008]FIG. 1 shows a configuration of a conventional photomask. The photomask has a reticle  14  and a pellicle  100 . The pellicle  100  includes a pellicle film  12  and a pellicle frame  10 .  
           [0009]    The pellicle  100  is manufactured by applying a good solvent of the pellicle film  12  on the top end face of a pellicle frame  10 , drying the solvent on the pellicle frame  10  with wind, and adhering the pellicle frame  10  on the transparent pellicle film  12  as disclosed in Japanese Patent Application Laid-Open No. S58-219023. The pellicle frame  10  is made from material such as nitrocellulose, cellulose acetate, or fluoroplastics, which has high optical permeability. The pellicle frame  10  can be made from material such as aluminum, stainless steel, or polyethylene, as examples.  
           [0010]    The pellicle  100  can also be manufactured by adhering the pellicle frame  10  on a pellicle film  12  with adhesive  20  as disclosed in U.S. Pat. No. 4,861,402, Japanese Patent Application publication No. S63-27707, and Japanese Patent Application Laid-Open No. H7-168345. Acrylic resin, epoxy resin, or fluoroplastics can be used as adhesive  20 . Also, an adhesive layer  22  and a separation layer for protecting the adhesive layer  22  is further adhered on a bottom end face of the pellicle frame  10 . An adhesive layer is made from material such as polybutene resin, polyvinyl acetate resin, acrylic resin, or silicon resin. Therefore, the pellicle film  12  is adhered to the pellicle frame  10  via the adhesive  20 . Then, the photomask  200  is manufactured by adhering the pellicle  100  on the reticle  14  with the adhesive  22 .  
           [0011]    Recently, the requirement for the resolution of the lithography has gradually increased. Therefore, a light having a shorter wavelength is gradually used to satisfy the requirement of the resolution. Specifically, instead of an ultraviolet light of g-line having 436 nm wavelength or i-line having 365 nm wavelengths, an extreme ultraviolet light of KrF excimer laser has been used recently. In the near future, a vacuum ultraviolet light such as an ArF excimer laser having 193 nm wavelength or an F 2  excimer laser having 158 nm wavelengths will be used.  
           [0012]    If the wavelength of the light becomes shorter, the photon energy of light becomes large. Thus, the deterioration of the material used for the lithography process becomes large. Especially, in a case of the pellicle film  12 , because the material used for the pellicle film  12  is organic material such as fluoroplastics, the pellicle film  12  tends to deteriorate easily when using the light having a shorter wavelength.  
           [0013]    Therefore, it is proposed to use an inorganic material for a material of a pellicle film  12 . In a case of using an inorganic material for the pellicle film  12 , the pellicle film  12  should have a larger thickness than the pellicle film  12  made of organic material in order to have enough strength because the inorganic compound layer is generally weak. However, if the thickness of the pellicle film  12 , which is made of inorganic material, is large, it becomes very important that the surface of the pellicle film  12  and the surface of the reticle  14  are accurately parallel to each other because of the optical restriction inside the stepper.  
           [0014]    Therefore, comparing the relationship between the surface of the pellicle film  12  made of organic material and the surface of the reticle  14 , the surface of the pellicle film  12  made of inorganic material and the surface of the reticle  14  should be more accurately parallel.  
           [0015]    If the pellicle film  12  is adhered to the pellicle frame  10  through the adhesive  20  as shown in FIG. 1, it is difficult to make the surface of the pellicle film  12  be accurately parallel to the surface of the reticle  14  because the thickness of the adhesive  20  is not uniform.  
           [0016]    Generally, the pellicle  100  is adhered to the reticle  14  through the adhesive  22 , which is applied on the bottom end of pellicle frame  10 . By pressing and adhering the bottom end face of the pellicle frame  10  to the reticle  14 , the adhesive layer protected by the separation layer of the adhesive  22  is collapsed, and the pellicle  100  thus be adhered to the reticle  14 .  
           [0017]    Because this adhesive  22  has elasticity, the distance between the bottom surface of the pellicle film  12  and the top surface of the reticle  22  changes according to the pressure applied on the pellicle  100  against the reticle  14 . If the distribution of weight applied on the pellicle  100  is different in each location inside the surface of the pellicle  100 , to which the reticle  14  is adhered, the height of the adhesive  22  becomes different for each location. Therefore, the surface of the pellicle film  12  and the surface of the reticle  14  do not become parallel to each other.  
         SUMMARY OF THE INVENTION  
         [0018]    Therefore, it is an object of the present invention to provide a pellicle, which is capable of overcoming the above drawbacks accompanying the conventional art. The above and other objects can be achieved by combinations described in the independent claims The dependent claims define further advantageous and exemplary combinations of the present invention.  
           [0019]    According to the first aspect of the present invention, a pellicle for protecting a reticle, on which a circuit pattern is formed for manufacturing a semiconductor device, from an attachment of a foreign matter, comprises: a pellicle film having a predetermined thickness, through which a light transmits to the reticle; and a pellicle frame, on which a periphery of the pellicle film contacts, including: a body part having a frame shape, the height which are substantially constant all over the body part; and an upper protruding part formed on an upper end of the body part that protrudes upward from the upper end of the body part for directly contacting with a surface of the pellicle film, the height of the upper protruding part being constant all over the upper protruding part.  
           [0020]    The upper protruding part may be formed on an inner edge of the upper end of the body part. The upper protruding part may be formed on an outer edge of the upper end of the body part. The upper protruding parts may be formed on both an inner edge and an outer edge of the upper end of the body part so that a recessed part is formed between the upper protruding parts.  
           [0021]    The pellicle may further comprise a lower protruding part formed on a lower end of the body part that protrudes downward from the lower end of the body part for directly contacting with a surface of the reticle, the height of the lower protruding part being constant all over the lower protruding part. The lower protruding part may be formed on an inner edge of the lower end of the body part. The lower protruding part may be formed on an outer edge of the lower end of the body part.  
           [0022]    The lower protruding parts may be formed on both an inner edge and an outer edge of the lower end of the body part so that a recessed part is formed between the lower protruding parts. The pellicle film and the pellicle frame may be adhered such that the upper protruding part directly contacts a surface of the pellicle film, and an upper end of the body part contacts the surface of the pellicle film through an adhesive.  
           [0023]    The pellicle frame and the reticle may be adhered such that the lower protruding part directly contacts a surface of the reticle, and a lower end of the body part contacts the surface of the reticle through an adhesive.  
           [0024]    A top end of the upper protruding part may have a sharp edge so that the upper protruding part is contacting the pellicle film at one point along a cross sectional direction perpendicular to a longitudinal direction of the upper protruding part. Furthermore, a bottom end of the lower protruding part may have a sharp edge so that the lower protruding part contacts the reticle at one point along a cross sectional direction perpendicular to a longitudinal direction of the lower protruding part.  
           [0025]    According to the second aspect of the present invention, a photomask comprises: a reticle, on which a circuit pattern is formed for manufacturing a semiconductor device; and a pellicle for protecting the reticle from an attachment of a foreign matter; wherein the pellicle has a pellicle film having a predetermined thickness, through which a light transmits to the reticle; and a pellicle frame, on which a periphery of the pellicle frame contacts, including: a body part having a frame shape, the height of which are substantially constant all over the body part; and an upper protruding part formed on an upper end of the body part that protrudes upward from the upper end of the body part for directly contacting with a surface of the pellicle film, the height of the upper protruding part being constant all over the upper protruding part.  
           [0026]    The photomask may further comprise a lower protruding part formed on a lower end of the body part that protrudes downward from the lower end of the body part for directly contacting with a surface of the reticle, the height of the lower protruding part being constant all over the lower protruding part.  
           [0027]    The upper protruding part may be formed on an inner edge of the upper end of the body part, and the lower protruding part is formed on an inner edge of the lower end of the body part. The upper protruding part may be formed on an outer edge of the upper end of the body part, and the lower protruding part may be formed on an outer edge of the lower end of the body part.  
           [0028]    The upper protruding part may be formed on both an inner edge and an outer edge of the upper end of the body part so that an upper recessed part is formed between the upper protruding parts; and the lower protruding part may be formed on both an inner edge and an outer edge of the lower end of the body part so that a lower recessed part is formed between the lower protruding parts.  
           [0029]    According to the third aspect of the present invention, a pellicle frame arranged between a reticle, on which a circuit pattern is formed for manufacturing a semiconductor device, and a pellicle film, through which a light transmits to the reticle, comprises: a first portion directly contacting the pellicle film; and a second portion contacting the pellicle film through an adhesive that adheres the pellicle frame to the pellicle film.  
           [0030]    The first portion may directly contact the reticle, and the second portion contacting the reticle through an adhesive that adheres the pellicle frame to the reticle. A difference of height between the first portion and the second portion may serve as an adhesive accommodation part for accommodating the adhesive.  
           [0031]    The summary of the invention does not necessarily describe all necessary features of the present invention. The present invention may also be a sub-combination of the features described above. The above and other features and advantages of the present invention will become more apparent from the following description of the embodiments taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0032]    [0032]FIG. 1 shows a configuration of a conventional photomask. The photomask has a reticle  14  and a pellicle  100 .  
         [0033]    [0033]FIGS. 2A and 2B show configuration of a pellicle frame  10 A of the present embodiment.  
         [0034]    [0034]FIG. 3 shows a configuration of a photomask manufactured using the pellicle frame  10 A shown in FIGS. 2A and 2B.  
         [0035]    [0035]FIG. 4 shows another cross sectional view of the pellicle frame  10 A.  
         [0036]    [0036]FIGS. 5A and 5B show configuration of another embodiment of the photomask of the present invention.  
         [0037]    [0037]FIGS. 6A and 6B show further another embodiment of the photomask of the present invention.  
         [0038]    [0038]FIG. 7 shows another embodiment of the pellicle frame of the present invention.  
         [0039]    [0039]FIG. 8 shows further another embodiment of the pellicle frame of the present invention.  
         [0040]    [0040]FIG. 9 shows further another embodiment of the pellicle frame of the present invention.  
         [0041]    [0041]FIG. 10 shows further another embodiment of the pellicle frame of the present invention.  
         [0042]    [0042]FIGS. 11A and 11B show configuration of another embodiment of the pellicle of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0043]    The invention will now be described based on the preferred embodiments, which do not intend to limit the scope of the present invention, but exemplify the invention. All of the features and the combinations thereof described in the embodiments are not necessarily essential to the invention.  
         [0044]    [0044]FIGS. 2A and 2B show configuration of a pellicle frame  10 A of the present embodiment. FIG. 2A shows an upper plan view of the pellicle frame  10 A. FIG. 2B shows a cross-sectional view of the pellicle frame  10 A.  
         [0045]    A pellicle frame  10 A has a body part  50  having a rectangular frame shape and an upper protruding part  16  formed all around an outer edge of the upper end  70  of the body part  50 . The shape of the pellicle frame  10 A can be various shapes other than rectangular shape such as circular shape or octagonal shape. Furthermore, the upper protruding part  16  is not necessarily formed all around the upper end  70  of the body part  50 . The upper protruding part can be formed on a part of the upper end  70  of the body part  50  as shown in FIG. 11A.  
         [0046]    The body part  50  and the upper protruding part  16  are integrally formed. The height of the body part  50  is substantially constant all over the body part  50 . The upper protruding part  16  protrudes upward from the upper end  70  of the body part. The height of the upper protruding part  16  is constant all over the upper protruding part  16 .  
         [0047]    A pellicle frame  10 A further has a lower protruding part  18  formed all around an outer edge of the lower end  72  of the body part  50 . The lower protruding part  18  is not necessarily formed all around the lower end  72  of the body part  50 . The lower protruding part can be formed on a part of the lower end  72  of the body part  50 . The lower protruding part  18  protrudes downward from the lower end  72  of the body part  50 . The body part  50  and the lower protruding part  18  are integrally formed. The height of the lower protruding part  18  is constant all over the lower protruding part  18 . A pellicle frame  10 A is formed by such as a rigid material such as metal, glass, ceramic, or plastic, which are conventionally known.  
         [0048]    As shown in FIG. 2B, an adhesive  24  is applied on the upper end  70  of the body part  50 . Here, the adhesive  24  is not applied on the top end of the upper protruding part  16  as shown in FIG. 2B. Preferably, the adhesive  24  is applied on the upper end  70  of the body part  50  such that the height of the adhesive  24  is slightly higher than the height of the upper protruding part  16 . A material such as acrylic resin, epoxy resin, fluoroplastics, polybutene resin, polyvinyl acetate resin, or silicon resin, which are conventionally known, can be used for the adhesive  24 .  
         [0049]    Furthermore, an adhesive  26  is applied on the lower end  72  of the body part  50  as shown in FIG. 2B. Here, the adhesive  26  is not applied on the bottom end of the lower protruding part  18 . Preferably, the adhesive  26  is applied on the lower end  72  of the body part  50  such that the height of the adhesive  26  is slightly higher than the height of the lower protruding part  18 . A material such as polybutene resin, polyvinyl acetate resin, acrylic resin, or silicon resin, which are conventionally known, can be used for the adhesive  26 .  
         [0050]    [0050]FIG. 3 shows a configuration of a photomask manufactured using the pellicle frame  10 A shown in FIG. 2A and 2B. A photomask  200 A has a pellicle film  12 , a pellicle frame  10 A, and a reticle  14 . The pellicle film  12  is transparent so that a light can transmit through the pellicle frame  12  onto the reticle  14 . The pellicle film  12  has a predetermined thickness in order to have enough strength.  
         [0051]    The pellicle film  12  is made from an inorganic compound. As an example of the inorganic compound, there are materials such as silica glass, calcium fluoride, and magnesium fluoride, which are excellent in extreme ultraviolet radiation permeability. A silica glass is the most preferable material to be used for the pellicle film  12 . A circuit pattern is formed on the reticle  14  so that a light that passes through the reticle  14  is irradiated onto the wafer to manufacture a semiconductor device. A conventional reticle may be used for the reticle  14  of the present embodiment.  
         [0052]    The pellicle frame  10 A is adhered to the pellicle film  12  by the adhesive  24  to form a pellicle  10 A. The pellicle film  12  and the pellicle frame  10 A are adhered such that the upper protruding part  16  of the pellicle frame  10 A directly contacts a surface of the pellicle film  12 . At this time, the periphery of the pellicle film  12  contacts the upper protruding part  16  of the pellicle frame  12 . By the above-mentioned process, the pellicle  100 A that protects the reticle  14  from a foreign matter can be manufactured.  
         [0053]    Furthermore, the pellicle  100 A and the reticle  14  is adhered by the adhesive  26  such that that the lower protruding part  18  of the pellicle  100 A directly contacts a surface of the reticle  14 . Then, the photomask  200 A used for manufacturing a semiconductor device is manufactured.  
         [0054]    The amount of adhesive  24  applied on the upper end  70  of the body part  50  is determined so that the upper protruding part  16  of the pellicle frame  10 A directly contacts a surface of the pellicle film  12 . Also, the amount of adhesive  26  applied on the lower end  72  of the body part  50  is determined such that the lower protruding part  18  of the pellicle  100 A directly contacts a surface of the reticle  14 . The amounts of adhesive  24  and  26  are adjusted according to the characteristic of the adhesive  24  and  26  such as viscosity, density, and curing speed of the adhesive  24  and  26 .  
         [0055]    Because the upper protruding part  16  of the pellicle frame  10 A directly contacts a surface of the pellicle film  12 , the distance between the pellicle film  12  and the pellicle frame  10 A is constant all over the pellicle  10 A. That is, the distance between the pellicle film  12  and the pellicle frame  10 A is substantially zero all over the pellicle  10 A. Furthermore, because the lower protruding part  18  of the pellicle  100 A directly contacts a surface of the reticle  14 , and because the height of the pellicle frame  10 A is constant all over the pellicle frame  10 A, the bottom surface of the pellicle film  12  of the pellicle  10 A becomes parallel to the top surface of the reticle  14 . In other words, the distance between the bottom surface of the pellicle film  12  and the top surface of the reticle  14  becomes constant all over the pellicle film  12 .  
         [0056]    Conventionally, the adhesives  20  and  22  adhere the pellicle frame  10  to the pellicle film  12  and the reticle  14  and also control the vertical position of the pellicle  100  against the reticle  14 .  
         [0057]    Contrary, in the present embodiment, the adhesives  24  and  26  only adhere the pellicle frame  10 A to the pellicle film  12  and the reticle  14 , respectively, in the pellicle  10 A. Instead of adhesive  24  and  26 , the upper protruding part  16  and the lower protruding part  18  of the pellicle frame  10 A control the vertical position of the pellicle  100 A against the reticle  14 . Because the pellicle frame  10 A is made of rigid material, the surface of the pellicle film  12  and the surface of the reticle  14  can be accurately parallel to each other if the height of the pellicle frame  10 A is accurately constant all over the pellicle frame  10 A.  
         [0058]    [0058]FIG. 4 shows another cross sectional view of the pellicle frame  10 A. The pellicle frame  10 A shown in FIG. 4 is the same as that shown in FIG. 2B except the location of division between a body part and a protruding part.  
         [0059]    In FIG. 2B, the pellicle frame  10 A is divided in a horizontal direction for each of the upper protruding part  16 , the body part, and the lower protruding part  18 . In FIG. 4, the pellicle frame  10 A is divided in a vertical direction.  
         [0060]    The pellicle frame  10 A has a first portion  92  that directly contacts the pellicle film  12  and a second portion  94  that contacts the pellicle film  12  through the adhesive  24 . The first portion  92  contacts the pellicle film  12  such that the top end  92 A of the first portion  92  directly contacts the pellicle film  12 . Furthermore, the first portion  92  contacts the reticle  14  such that the bottom end  92 B of the first portion  92  directly contacts the reticle  14 . The second portion  92  contacts the reticle  14  through the adhesive  26 .  
         [0061]    The first portion  92  of FIG. 4 corresponds to the sum of the upper protruding part  16 , a part of the body part  50 , and the lower protruding part  18  shown in FIG. 2B. The second portion  94  of FIG. 4 corresponds to a part of the body part  50  shown in FIG. 2B.  
         [0062]    A difference of height H 1  and H 2  between the first portion  92  and the second portion  94  serves as an adhesive accommodation part for accommodating the adhesives  24  and  26 .  
         [0063]    [0063]FIGS. 5A and 5B show configuration of another embodiment of the photomask of the present invention. The configuration of the photomask  2003  shown in FIGS. 5A and 5B are the same as the configuration of FIG. 3 except the position where the upper protruding part  28  and the lower protruding part  30  are formed.  
         [0064]    The upper protruding part  28  shown in FIGS. 5A and 5B is formed all around the inner edge of the upper end  32  of the body part  50 . The upper protruding part  28  is not necessarily formed all around the upper end  32  of the body part  50 . The upper protruding part  28  can be formed on a part of the upper end  32  of the body part  50 . Also, the lower protruding part  30  is formed all around the inner edge of the lower end  34  of the body part  50 . The lower protruding part  30  is not necessarily formed all around the upper end  34  of the body part  50 . The lower protruding part can be formed on a part of the lower end  34  of the body part  50 . The upper protruding part  28 , the body part  50 , and the lower protruding part  30  are integrally formed.  
         [0065]    Because the upper protruding part  28  of the pellicle frame  10 B directly contacts a surface of the pellicle film  12 , the vertical position of the surface of the pellicle film  12  against the pellicle frame  10 B is constant all over the pellicle  10 B. Furthermore, because the lower protruding part  30  of the pellicle  100 B directly contacts a surface of the reticle  14 , the bottom surface of the pellicle film  12  of the pellicle  10 B becomes parallel to the top surface of the reticle  14 . In other words, the distance between the bottom surface of the pellicle film  12  and the top surface of the reticle  14  becomes constant all over the pellicle film  12 .  
         [0066]    [0066]FIGS. 6A and 6B show further another embodiment of the photomask of the present invention. The configuration of the photomask  200 C shown in FIGS. 6A and 6B are the same as the configuration of FIG. 3 except that two upper protruding parts  16  and  28  and two lower protruding parts  18  and  30  are formed.  
         [0067]    The upper protruding parts  16  and  28  are formed all around both the inner edge and outer edge of the upper end  40  of the body part  50  so that an upper recessed part  40  is formed between the upper protruding parts  16  and  28 . Furthermore, the lower protruding parts  18  and  30  are formed all around both the inner edge and outer edge of the lower end  46  of the body part  50  so that a lower recessed part  40  is formed between the lower protruding parts  18  and  30 . The height of the upper protruding parts  16  and  28  are the same, and the height of the lower protruding parts  18  and  30  are the same.  
         [0068]    The upper protruding parts  16  and  28  are not necessarily formed all around the upper end  40  of the body part  50 . The upper protruding parts  16  and  28  can be formed on a part of the upper end  40  of the body part  50 . Also, the lower protruding parts  18  and  30  are not necessarily formed all around the lower end  46  of the body part  50 . The lower protruding parts  18  and  30  can be formed on a part of the lower end  46  of the body part  50 .  
         [0069]    Because the upper protruding parts  16  and  28  of the pellicle frame  10 C directly contact a surface of the pellicle film  12 , the vertical position of the pellicle film  12  against the pellicle frame  10 C is constant all over the pellicle  10 C. Furthermore, because the lower protruding parts  18  and  30  of the pellicle  100 C directly contact a surface of the reticle  14 , the bottom surface of the pellicle film  12  of the pellicle  10 C becomes parallel to the top surface of the reticle  14 . In other words, the distance between the bottom surface of the pellicle film  12  and the top surface of the reticle  14  becomes constant all over the region of the pellicle film  12 .  
         [0070]    [0070]FIG. 7 shows another embodiment of the pellicle frame of the present invention. The configuration of the pellicle frame  10 D shown in FIG. 7 is the same as that shown in FIG. 2B except that a top end  80 E of the upper protruding part  80  has a sharp edge. The upper protruding part  80  is formed all around an outer edge of the upper end  70  of the body part  50 . Also, the lower protruding part  82  is formed all around an outer edge of the lower end  34  of the body part  50 .  
         [0071]    The upper protruding part  80  is not necessarily formed all around the upper end  70  of the body part  50 . The upper protruding part can be formed on a part of the upper end  70  of the body part  50 . Also, the lower protruding part  82  is not necessarily formed all around the lower end  34  of the body part  50 . The lower protruding part  82  can be formed on a part of the lower end  34  of the body part  50 .  
         [0072]    Because the top end  80 E of the upper protruding part  80  has a sharp edge, the upper protruding part  80  contacts the pellicle film  12  at one point, which is the top end  8 oE, along a cross sectional direction perpendicular to the longitudinal direction of the upper protruding part  80 . If the top plan view of the connection between the pellicle frame  10 D and the pellicle film  12  is shown, the shape of the connection is shown as a linear shape.  
         [0073]    Thus, when the pellicle frame  10 D is pushed and adhered to the pellicle film  12 , the adhesive applied on the upper protruding part  80  escapes from the top end  80 E of the upper protruding part  80 . Therefore, the top end  80 E of the upper protruding part  80  can directly and reliably contact a surface of the pellicle film  12 . Thus, the vertical position of the pellicle film  12  against the pellicle frame  10 D becomes constant all over the pellicle frame  10 D because the pellicle frame  10 D directly and reliably contacts the surface of the pellicle film  12  all over the pellicle frame  10 D.  
         [0074]    Furthermore, because the bottom end  82 E of the lower protruding part  82  also has a sharp edge, the lower protruding part  82  contacts the reticle  14  at one point, which is the bottom end  82 E, along a cross sectional direction perpendicular to the longitudinal direction of the lower protruding part  82 . If the bottom plan view of the connection between the pellicle frame  10 D and the reticle  14  is shown, the shape of the connection is shown as a linear shape.  
         [0075]    Thus, when the pellicle frame  10 D is pushed and adhered to the reticle  14 , the adhesive applied on the lower protruding part  86  escapes from the bottom end  82 E of the lower protruding part  82 . Therefore, the bottom end  82 E of the lower protruding part  82  can directly and reliably contact a surface of the reticle  14 . Thus, the bottom surface of the pellicle film  12  becomes parallel to the top surface of the reticle  14 . In other words, the distance between the bottom surface of the pellicle film  12  and the top surface of the reticle  14  becomes reliably constant all over the region of the pellicle film  12 .  
         [0076]    [0076]FIG. 8 shows further another embodiment of the pellicle frame of the present invention. The configuration of the pellicle frame  10 E shown in FIG. 8 is the same as that shown in FIG. 5B except that a top end  84 E of the upper protruding part  84  has a sharp edge. The upper protruding part  84  is formed all around an inner edge of the upper end  32  of the body part  50 . Also, the lower protruding part  86  is formed all around an inner edge of the lower end  34  of the body part  50 .  
         [0077]    The upper protruding part  84  is not necessarily formed all around the upper end  32  of the body part  50 . The upper protruding part  84  can be formed on a part of the upper end  32  of the body part  50 . Also, the lower protruding part  86  is not necessarily formed all around the lower end  34  of the body part  50 . The lower protruding part can be formed on a part of the lower end  34  of the body part  50 .  
         [0078]    Because the top end  84 E of the upper protruding part  84  has a sharp edge, the upper protruding part  84  contacts the pellicle film  12  at one point, which is the top end  84 E, along across sectional direction perpendicular to the longitudinal direction of the upper protruding part  84 . If the top plan view of the connection between the pellicle frame  10 E and the pellicle film  12  is shown, the shape of the connection is shown as a linear shape.  
         [0079]    Thus, when the pellicle frame  10 E is pushed and adhered to the pellicle film  12 , the adhesive applied on the upper protruding part  84  escapes from the top end  84 E of the upper protruding part  84 . Therefore, the top end  84 E of the upper protruding part  84  can directly and reliably contact a surface of the pellicle film  12 . Thus, the vertical position of the pellicle film  12  against the pellicle frame  10 E becomes constant all over the pellicle frame  10 E because the pellicle frame  10 E directly and reliably contacts the surface of the pellicle film  12  all over the pellicle frame  10 E.  
         [0080]    Furthermore, because the bottom end  86 E of the lower protruding part  86  also has a sharp edge, the lower protruding part  86  contacts the reticle  14  at one point, which is the bottom end  86 E, along a cross sectional direction perpendicular to the longitudinal direction of the lower protruding part  86 . If the bottom plan view of the connection between the pellicle frame  10 E and the reticle  14  is shown, the shape of the connection is shown as a linear shape.  
         [0081]    Thus, when the pellicle frame  10 E is pushed and adhered to the reticle  14 , the adhesive applied on the lower protruding part  86  escapes from the bottom end  86 E of the lower protruding part  86 . Therefore, the bottom end  86 E of the lower protruding part  86  can directly and reliably contact a surface of the reticle  14 . Thus, the bottom surface of the pellicle film  12  becomes parallel to the top surface of the reticle  14 . In other words, the distance between the bottom surface of the pellicle film  12  and the top surface of the reticle  14  becomes reliably constant all over the region of the pellicle film  12 .  
         [0082]    [0082]FIG. 9 shows further another embodiment of the pellicle frame of the present invention. The configuration of the pellicle frame  10 F shown in FIG. 9 is the same as that shown in FIG. 6B except that top ends  80 E and  84 E of the upper protruding parts  80  and  84  have a sharp edge. The upper protruding parts  80  and  84  are formed all around both of an inner edge and an outer edge of the upper end  40  of the body part  50 , respectively. Also, the lower protruding parts  82  and  86  are formed all around both of an inner edge and an outer edge of the lower end  46  of the body part  50 , respectively.  
         [0083]    The upper protruding parts  80  and  84  are not necessarily formed all around the upper end  40  of the body part  50 . The upper protruding parts  80  and  84  can be formed on a part of the upper end  40  of the body part  50 . Also, the lower protruding parts  82  and  86  are not necessarily formed all around the lower end  46  of the body part  50 . The lower protruding parts  82  and  86  can be formed on a part of the lower end  46  of the body part  50 .  
         [0084]    Because the top end  80 E of the upper protruding part  80  has a sharp edge, the upper protruding part  80  contacts the pellicle film  12  at one point, which is the top end  80 E, along a cross sectional direction perpendicular to the longitudinal direction of the upper protruding part  80 . Also, because the top end  84 E of the upper protruding part  84  has a sharp edge, the upper protruding part  84  contacts the pellicle film  12  at one point, which is the top end  84 E, along a cross sectional direction perpendicular to the longitudinal direction of the upper protruding part  84 . If the top plan view of the connection between the pellicle frame  10 F and the pellicle film  12  is shown, the shape of the connection is shown as two-linear shapes.  
         [0085]    Thus, when the pellicle frame  10 F is pushed and adhered to the pellicle film  12 , the adhesive applied on the upper protruding parts  80  and  84  escapes from the top ends  80 E and  84 E of the upper protruding parts  80  and  84 . Therefore, the top ends  80 E and  84 E of the upper protruding parts  80  and  84  can directly and reliably contact a surface of the pellicle film  12 . Thus, the vertical position of the pellicle film  12  against the pellicle frame  10 F becomes constant all over the pellicle frame  10 F because the pellicle frame  10 F directly and reliably contacts the surface of the pellicle film  12  all over the pellicle frame  10 F.  
         [0086]    Furthermore, because the bottom end  82 E of the lower protruding part  82  also has a sharp edge, the lower protruding part  82  contacts the reticle  14  at one point, which is the bottom end  82 E, along a cross sectional direction perpendicular to the longitudinal direction of the lower protruding part  82 . Also, because the bottom end  86 E of the lower protruding part  86  also has a sharp edge, the lower protruding part  86  contacts the reticle  14  at one point, which is the bottom end  86 E, along a cross sectional direction perpendicular to the longitudinal direction of the lower protruding part  86 . If the bottom plan view of the connection between the pellicle frame  10 F and the reticle  14  is shown, the shape of the connection is shown as two-linear shapes.  
         [0087]    Thus, when the pellicle frame  10 F is pushed and adhered to the reticle  14 , the adhesive applied on the lower protruding parts  82  and  86  escapes from the bottom ends  82 E and  86 E of the lower protruding parts  82  and  86 . Therefore, the bottom ends  82 E and  86 E of the lower protruding parts  82  and  86  can directly and reliably contact a surface of the reticle  14 . Thus, the bottom surface of the pellicle film  12  becomes parallel to the top surface of the reticle  14 . In other words, the distance between the bottom surface of the pellicle film  12  and the top surface of the reticle  14  becomes reliably constant all over the region of the pellicle film  12 .  
         [0088]    [0088]FIG. 10 shows further another embodiment of the pellicle frame of the present invention. The upper protruding part  88  is formed all around a central part of the upper end  92  of the body part  50 . Also, the lower protruding part  90  is formed all around a central part of the lower end  94  of the body part  50 .  
         [0089]    The upper protruding part  88  is not necessarily formed all around the upper end  92  of the body part  50 . The upper protruding part  88  can be formed on a part of the upper end  92  of the body part  50 . Also, the lower protruding part  90  is not necessarily formed all around the lower end  94  of the body part  50 . The lower protruding part  90  can be formed on a part of the lower end  94  of the body part  50 .  
         [0090]    Because the top end  88 E of the upper protruding part  88  has a sharp edge, the upper protruding part  88  contacts the pellicle film  12  at one point, which is the top end  88 E, along a cross sectional direction perpendicular to the longitudinal direction of the upper protruding part  88 . If the top plan view of the connection between the pellicle frame  10 G and the pellicle film  12  is shown, the shape of the connection is shown as a linear shape.  
         [0091]    Thus, when the pellicle frame  10 G is pushed and adhered to the pellicle film  12 , the adhesive applied on the upper protruding part  88  escapes from the top end  88 E of the upper protruding part  88 . Therefore, the top end  88 E of the upper protruding part  88  can directly and reliably contact a surface of the pellicle film  12 . Thus, the vertical position of the pellicle film  12  against the pellicle frame  10 G becomes constant all over the pellicle frame  10 G because the pellicle frame  10 G directly and reliably contacts the surface of the pellicle film  12  all over the pellicle frame  10 G.  
         [0092]    Furthermore, because the bottom end  90 E of the lower protruding part  90  also has a sharp edge, the lower protruding part  90  contacts the reticle  14  at one point, which is the bottom end  90 E, along a cross sectional direction perpendicular to the longitudinal direction of the lower protruding part  90 . If the bottom plan view of the connection between the pellicle frame  10 G and the reticle  14  is shown, the shape of the connection is shown as a linear shape.  
         [0093]    Thus, when the pellicle frame lOG is pushed and adhered to the reticle  14 , the adhesive applied on the lower protruding part  90  escapes from the bottom end  90 E of the lower protruding part  90 . Therefore, the bottom end  90 E of the lower protruding part  90  can directly and reliably contact a surface of the reticle  14 . Thus, the bottom surface of the pellicle film  12  becomes parallel to the top surface of the reticle  14 . In other words, the distance between the bottom surface of the pellicle film  12  and the top surface of the reticle  14  becomes reliably constant all over the region of the pellicle film  12 .  
         [0094]    [0094]FIGS. 11A and 11B show configuration of another embodiment of the pellicle of the present invention. The configuration of the pellicle  10 H shown in FIGS. 11A and 11B are the same as the configuration of FIG. 2 except the upper protruding parts  100  and lower protruding parts  102  are formed only on corners of the body part  50 . As shown in FIG. 11A, the upper protruding part and lower protruding part can be formed on a part of the body part  50 .  
       EXAMPLE 1  
       [0095]    The pellicle frame  10 A as shown in FIGS. 2A and 2B was used for manufacturing a pellicle  100 A. The pellicle frame  10 A was made of aluminum. The pellicle frame  10 A had a rectangular plan shape as shown in FIG. 2A. The body part  50  of the pellicle frame  10 A is 150 mm by 120 mm in size, 5 mm height, and 6 mm width. The upper protruding part  16  was formed all around the outer edge of the upper end  70  of the body part  50 . Also, the lower protruding part  18  was formed all around the outer edge of the lower end  72  of the body part  50 . Each of the upper protruding part  16  and lower protruding part  18  has 1 mm height and 3 mm width. The body part  50 , the upper protruding part  16 , and the lower protruding part  18  are integrally formed.  
         [0096]    A difference between the degree of an inclination of the face formed by connecting the top ends of the upper protruding part  16  and the degree of inclination of the face formed by connecting the bottom ends of the lower protruding part  18  was measured. The difference of the degree of the inclination of the two faces was measured to measure how much the two faces were parallel to each other. The difference obtained by the measurement was 5 μm.  
         [0097]    The adhesive  24  was applied all around the upper end  70  of the body part  50  of the pellicle frame  10 A. An epoxy adhesive of “SUPER BY” manufactured by Cemedine Co., Ltd. was used for the adhesive  26 . Also, the adhesive  26  was applied all around the lower end  72  of the body part  50  of the pellicle frame  10 A. A silicon adhesive of “X-40-3004” manufactured by Shin-Etsu Chemical Co., Ltd. was used as the adhesive  24 . At this time, the adhesive  24  was applied on the upper end  70  of the body part  50  such that the height of the adhesive  24  was slightly higher than the height of the upper protruding part  16 . Furthermore, the adhesive  26  was applied on the lower end  72  of the body part  50  such that the height of the adhesive  26  was slightly higher than the height of the lower protruding part  18 .  
         [0098]    A pellicle film  12  having 1 mm thickness was adhered to the pellicle frame  10 A to form a pellicle  100 A. The pellicle film  12  was made of quartz glass. At this time, the upper protruding part  16  of the pellicle frame  10 A directly contacted a surface of the pellicle film  12 .  
         [0099]    Then, the pellicle  100 A was pressed and adhered to the reticle  14  to form a photomask  200 A as shown in FIG. 3. At this time, the lower protruding part  18  of the pellicle  100 A directly contacted a surface of the reticle  14 .  
         [0100]    A difference between the degree of an inclination of the pellicle film  12  and the degree of an inclination of the reticle  14  was measured. The difference between the degree of the inclination of the pellicle film  12  and that of the reticle  14  was measured to measure how much the pellicle film  12  and the reticle  14  were parallel to each other. The difference obtained by the measurement was 5 μm, which was the same difference obtained by measuring the difference between the degree of the inclination of the face formed by connecting the top ends of the upper protruding part  16  and that of the face formed by connecting the bottom ends of the lower protruding part  18 .  
       EXAMPLE 2  
       [0101]    The pellicle frame  10 B as shown in FIGS. 5A and 5B was used for manufacturing a pellicle  100 B. The pellicle frame  10 B was made of aluminum. The pellicle frame  10 B had a rectangular plan shape as shown in FIG. 5A. The body part  50  of the pellicle frame  10 B is 150 mm by 120 mm in size, 5 mm height, and 6 mm width. The upper protruding part  28  was formed all around the inner edge of the upper end  32  of the body part  50 . Also, the lower protruding part  30  was formed all around the inner edge of the lower end  34  of the body part  50 . Each of the upper protruding part  28  and lower protruding part  30  has 1 mm height and 3 mm width. The body part  50 , the upper protruding part  28 , and the lower protruding part  30  are integrally formed.  
         [0102]    A difference between the degree of an inclination of the face formed by connecting the top ends of the upper protruding part  28  and the degree of inclination of the face formed by connecting the bottom ends of the lower protruding part  30  was measured. The difference of the degree of the inclination of the two faces was measured to measure how much the two faces were parallel to each other. The difference obtained by the measurement was 5 μm.  
         [0103]    The adhesive  60  was applied all around the upper end  32  of the body part  50  of the pellicle frame  10 B. An epoxy adhesive of “SUPER B” manufactured by Cemedine Co., Ltd. was used for the adhesive  60 . Also, the adhesive  62  was applied all around the lower end  34  of the body part  50  of the pellicle frame  10 A. A silicon adhesive of “X-40-3004” manufactured by Shin-Etsu Chemical Co., Ltd. was used as the adhesive  62 . At this time, the adhesive  60  was applied on the upper end  32  of the body part  50  such that the height of the adhesive  60  was slightly higher than the height of the upper protruding part  28 . Furthermore, the adhesive  62  was applied on the lower end  34  of the body part  50  such that the height of the adhesive  62  was slightly higher than the height of the lower protruding part  30 .  
         [0104]    A pellicle film  12  having 1 mm thickness was adhered to the pellicle frame  10 B to form a pellicle  100 B. The pellicle film  12  was made of quartz glass. At this time, the upper protruding part  28  of the pellicle frame  10 B directly contacted a surface of the pellicle film  12 .  
         [0105]    Then, the pellicle  100 B was pressed and adhered to the reticle  14  to form a photomask  200 B as shown in FIG. 5B. At this time, the lower protruding part  30  of the pellicle  100 B directly contacted a surface of the reticle  14 .  
         [0106]    A difference between the degree of an inclination of the pellicle film  12  and the degree of an inclination of the reticle  14  was measured. The difference between the degree of the inclination of the pellicle film  12  and that of the reticle  14  was measured to measure how much the pellicle film  12  and the reticle  14  were parallel to each other. The difference obtained by the measurement was 5 μm, which was the same difference obtained by measuring the difference between the degree of the inclination of the face formed by connecting the top ends of the upper protruding part  28  and that of the face formed by connecting the bottom ends of the lower protruding part  30 .  
       EXAMPLE 3  
       [0107]    The pellicle frame  10 C as shown in FIGS. 6A and 6B was used for manufacturing a pellicle lOOC. The pellicle frame  10 C was made of aluminum. The pellicle frame  10 C had a rectangular plan shape as shown in FIG. 6A. The body part  50  of the pellicle frame  10 C is 150 mm by 120 mm in size, 5 mm height, and 6 mm width. The body part  50 , the upper protruding parts  16  and  28 , and the lower protruding parts  18  and  30  are integrally formed.  
         [0108]    The upper protruding parts  16  and  28  are formed all around both the inner edge and outer edge of the upper end  40  of the body part  50  so that an upper recessed part  40  is formed between the upper protruding parts  16  and  28 . Also, the lower protruding parts  18  and  30  are formed all around both the inner edge and outer edge of the lower end  46  of the body part  50  so that a lower recessed part  46  is formed between the lower protruding parts  18  and  30 . Each of the upper protruding parts  16  and  28  and lower protruding parts  18  and  30  has 1 mm height and 3 mm width. Furthermore, the height of the upper protruding parts  16  and  28  are the same, and the height of the lower protruding parts  18  and  30  are the same.  
         [0109]    A difference between the degree of an inclination of the face formed by connecting the top ends of the upper protruding parts  16  and  28  and the degree of inclination of the face formed by connecting the bottom ends of the lower protruding parts  18  and  30  was measured. The difference of the degree of the inclination of two faces was measured to measure h how much the two faces were parallel to each other. The difference obtained by the measurement was 5 μm.  
         [0110]    The adhesive  64  was applied all around the upper recessed part  40  formed by the upper protruding parts  28  and  16  of the pellicle frame  10 A. An epoxy adhesive of “SUPERB ” manufactured by Cemedine Co., Ltd. was used for the adhesive  64 . Also, the adhesive  66  was applied all around the lower recessed part  46  formed by the lower protruding parts  18  and  30  of the pellicle frame  10 A. A silicon adhesive of “X-40-3004” manufactured by Shin-Etsu Chemical Co., Ltd. was used as the adhesive  66 . At this time, the adhesive  64  is applied on the recessed part  40  such that the height of the adhesive  64  was slightly higher than the height of the upper protruding parts  16  and  28 . Furthermore, the adhesive  66  was applied on the lower recessed part  66  such that the height of the adhesive  66  was slightly higher than the height of the lower protruding parts  18  and  30 .  
         [0111]    A pellicle film  12  having 1 mm thickness was adhered to the pellicle frame  10 C to form a pellicle  100 C. The pellicle film  12  was made of quartz glass. At this time, the upper protruding parts  16  and  28  of the pellicle frame  10 C directly contacted a surface of the pellicle film  12 .  
         [0112]    Then, the pellicle  100 C was pressed and adhered to the reticle  14  to form a photomask  200 C as shown in FIG. 6B. At this time, the lower protruding parts  18  and  30  of the pellicle  100 C directly contacted a surface of the reticle  14 .  
         [0113]    A difference between the degree of an inclination of the pellicle film  12  and the degree of an inclination of the reticle  14  was measured. The difference between the degree of the inclination of the pellicle film  12  and that of the reticle  14  was measured to measure how much the pellicle film  12  and the reticle  14  were parallel to each other. The difference obtained by the measurement was 5 μm, which was the same difference obtained by measuring the difference between the degree of the inclination of the face formed by connecting the top ends of the upper protruding parts  16  and  28  and that of the face formed by connecting the bottom ends of the lower protruding parts  18  and  30 .  
       Comparative Example 1  
       [0114]    The pellicle frame  10  as shown in FIG. 1 was used for manufacturing a pellicle  100 . The pellicle frame  10  was made of aluminum. The pellicle frame  10  had a rectangular plan shape. The pellicle frame  10  is 150 mm by 120 mm in size, 5 mm height, and 6 mm width. The pellicle frame  10  did not have a protruding part.  
         [0115]    A difference between the degree of an inclination of the face formed by connecting the upper ends of the pellicle frame  10  and the degree of inclination of the face formed by connecting the lower ends of the pellicle frame  10  was measured. The difference of the degree of the inclination of two faces was measured to measure how much the two faces were parallel to each other. The difference obtained by the measurement was 5 μm.  
         [0116]    The adhesive  20  was applied all around the upper end of the pellicle frame  10 . An epoxy adhesive of “SUPER B” manufactured by Cemedine Co., Ltd. was used for the adhesive  20 . Also, the adhesive  22  was applied all around the lower end of the pellicle frame  10 . A silicon adhesive of “X-40-3004” manufactured by Shin-Etsu Chemical Co., Ltd. was used as the adhesive  22 .  
         [0117]    A pellicle film  12  having 1 mm thickness was adhered to the upper end face of the pellicle frame  10  to form a pellicle  100 . The pellicle film  12  was made of quartz glass. At this time, the upper end face of the pellicle frame  10  was adhered to the pellicle film  12  with the adhesive  20 . Therefore, the pellicle frame  10  contacted the pellicle film  12  through the adhesive  20  and did not directly contact the pellicle film  12 .  
         [0118]    Then, the pellicle  100  was pressed and adhered to the reticle  14  to form a photomask  200  as shown in FIG. 1. At this time, the lower end face of the pellicle frame  10  was adhered to the reticle  14  with the adhesive  22 . Therefore, the pellicle frame  10  contacted the reticle  14  through the adhesive  22  and did not directly contact the reticle  14 .  
         [0119]    A difference between the degree of an inclination of the pellicle film  12  and the degree of an inclination of the reticle  14  was measured. The difference between the degree of the inclination of the pellicle film  12  and that of the reticle  14  was measured to measure how much the pellicle film l 2  and the reticle  14  were parallel to each other. The difference obtained by the measurement was 40 μm, which was much larger than the difference obtained by measuring the difference between the degree of the inclination of the face formed by connecting the upper ends of the pellicle frame  10  and that of the face formed by connecting the lower ends of the pellicle frame  10 .  
         [0120]    As described above, by the pellicle  10  shown in FIG. 1 and explained in the COMPARATIVE EXAMPLE, it is difficult to make the surface of the pellicle film  12  and the surface of the reticle  14  be accurately parallel to each other even if the face formed by the top ends of the upper protruding part and the face formed by the bottom ends of the lower protruding part are accurately parallel to each other because the thickness of the adhesive  20  and  22  is not uniform around the pellicle frame  10 .  
         [0121]    Contrary, the pellicle of the present embodiment can make the surface of the pellicle film  12  and the surface of the reticle  14  be accurately parallel to each other if the face formed by the top ends of the upper protruding part and the face formed by the bottom ends of the lower protruding part are accurately parallel to each other. Therefore, a photomask having high quality can be easily obtained by the present embodiment.  
         [0122]    Although the present invention has been described by way of exemplary embodiments, it should be understood that those skilled in the art might make many changes and substitutions without departing from the spirit and the scope of the present invention which is defined only by the appended claims.

Technology Category: 3