Abstract:
The present invention is a transfer mask for exposure comprising a mask portion having a plurality of cells, each of which an opening of a predetermined pattern is formed in. When one side of the plurality of cells is exposed to a charged particle beam, each of the plurality of cells is adapted to make the charged particle beam pass through itself to the other side thereof based on the pattern of the opening formed in the cell. Thus, when a substrate to be processed is arranged on the other side of the cell, the pattern of the opening formed in the cell is transferred to the substrate to be processed and hence an exposure pattern is formed on the substrate to be processed. The feature of the present invention is that a part of or all the plurality of cells can be exchanged at the mask portion.

Description:
TECHNICAL FIELD 
     The present invention relates to a transfer mask for exposure, which is used in an exposure process by means of a charged particle beam such as an electron beam, and to a pattern exchanging method of the transfer mask for exposure. 
     BACKGROUND ART 
     In manufacturing semiconductor devices, lithography technique is used for a pattern formation. Conventionally, reduction projecting lithography technique wherein a mask is used is mainly used as the lithography technique. The reduction projecting lithography technique can achieve high throughput. However, the reduction projecting lithography technique needs an expensive mask set, which may be several decade million yen to one hundred million yen. In the present semiconductor industry, general LSI has been changed to system LSI, which is manufactured mainly through small-amount but many-kinds production. Thus, it is difficult to regain the high mask cost. In addition, mask manufacturing time is as long as one month, which is fatal in the system LSI that requires short TAT (turn-around time). 
     As a new-era lithography technique that solves the above problem, electron-beam direct writing technique has been paid attention to. According to the electron-beam direct writing technique, it is unnecessary to use an expensive mask, differently from the conventional reduction projecting lithography technique, but it is possible to form a minute pattern of 0.15 μm or smaller. That is, the above problem caused by the mask can be solved. However, the electron-beam direct writing technique has a defect of low throughput. 
     A character-projection (CP) type of technique has been proposed as a technique of improving the throughput in the electron-beam lithography technique. In that technique, a transfer mask for exposure, which is called a CP aperture mask and has a lot of various-character-patterned cells, is formed, and a semiconductor wafer is exposed to an electron beam selectively through a specific character pattern of the CP aperture mask. Thus, a pattern can be exposed at the one-time exposure step, although the pattern needs a lot of beam shots by the conventional variable shape writing manner or the like. Thus, the writing speed can be remarkably increased. That is, the throughput can be remarkably enhanced. 
     However, in the character-projection type of technique, various character patterns have to be formed in the CP aperture mask in advance. Thus, if a user wants to change a pattern to another, or if a part of the cells has a defect or the like, the whole CP aperture mask has to be manufactured from the beginning. This is a problem in view of cost and delivery time of the CP aperture mask. 
     SUMMARY OF THE INVENTION 
     This invention is developed by focusing the aforementioned problems. The object of the present invention is to provide a transfer mask for exposure and a pattern exchanging method of the transfer mask for exposure, which can cope with a case wherein a user wants to change a pattern or another case wherein a part of cells has a defect, in the character-projection type of technique. 
     In order to solve the above problems, the present invention is a transfer mask for exposure comprising a mask portion having a plurality of cells, each of which an opening of a predetermined pattern is formed in, wherein when one side of the plurality of cells is exposed to a charged particle beam, each of the plurality of cells is adapted to make the charged particle beam pass through itself to the other side thereof based on the pattern of the opening formed in the cell, so that when a substrate to be processed is arranged on the other side of the cell, the pattern of the opening formed in the cell is transferred to the substrate to be processed and an exposure pattern is formed on the substrate to be processed, and wherein a part of or all the plurality of cells can be exchanged at the mask portion. 
     According to the above feature, since the part of or all the plurality of cells, each of which an opening of a predetermined pattern is formed in, can be exchanged, if a user wants to change a pattern to another or if a pattern has a defect or the like, a cell including the pattern can be exchanged. Thus, even if a user wants to change-a pattern to another or even if a pattern has a defect or the like, it is unnecessary to manufacture a new transfer mask for exposure from the beginning. Therefore, a problem of cost and delivery time of the new transfer mask for exposure doesn&#39;t arise. 
     Preferably, the mask portion has one or more blocks, each of which contains one or more cells, and the plurality of cells can be exchanged by every block. In the case, the number of cells to be exchanged at a time can be freely set. 
     In addition, preferably, the blocks are arranged in such a manner that a circle (tangent circle) surrounding all the blocks has a minimum diameter. In the case, deflection of the charged particle beam can be reduced as much as possible. 
     For example, each of the blocks contains a plurality of rectangular cells that are arranged in a square shape. 
     Preferably, the mask portion mainly consists of silicon. 
     In addition, the present invention is a transfer mask for exposure comprising a mask portion having a plurality of cells, each of which an opening of a predetermined pattern is formed in; wherein the mask portion has one or more blocks, each of which contains one or more cells, the mask portion has one or more supporting parts that support the one or more blocks, the mask portion has one or more adhesive members that adhesively connect the one or more blocks and the one or more supporting parts and are capable of being removed at any time, and the one or more blocks can be exchanged to new blocks by removing the corresponding one or more adhesive members. 
     According to the above feature, since the one or more blocks can be exchanged to new blocks by removing the corresponding one or more adhesive members, if a user wants to change a pattern to another or if a pattern has a defect or the like, a block including the pattern can be exchanged. Thus, even if a user wants to change a pattern to another or even if a pattern has a defect or the like, it is unnecessary to manufacture a new transfer mask for exposure from the beginning. Therefore, a problem of cost and delivery time of the new transfer mask for exposure doesn&#39;t arise. 
     In addition, an operation of exchanging the block can be easily carried out because the block can be removed by only removing the adhesive member. 
     Preferably, each of the supporting parts contains a stopper part that positions the corresponding block via the adhesive member, and a beam part that supports the stopper part and that protrudes under the corresponding block. 
     In the case, after a previous block is removed, a new block can be placed on the beam part. In addition, the new block can be positioned by the stopper part, so that the new block can be mounted easily. 
     Preferably, each of the supporting parts is arranged to surround the corresponding block, and one or more adhesive members are arranged at the whole circumference of the block or at a plurality of positions around the block. 
     In addition, preferably, the blocks are arranged in such a manner that a circle surrounding all the blocks has a minimum diameter. In the case, deflection of the charged particle beam can be reduced as much as possible. 
     For example, each of the blocks contains a plurality of rectangular cells that are arranged in a square shape. 
     Preferably, the blocks and the supporting parts mainly consist of silicon, and the adhesive members consist of a material including carbon. 
     In addition, the present invention is a pattern exchanging method of a transfer mask for exposure, the transfer mask for exposure including a mask portion having a plurality of cells, each of which an opening of a predetermined pattern is formed in, wherein the mask portion has one or more blocks, each of which contains one or more cells, the mask portion has one or more supporting parts that supports the one or more blocks, the mask portion has one or more adhesive members that adhesively connects the one or more blocks and the one or more supporting parts and are capable of being removed at any time, and each of the supporting parts contains a stopper part that positions the corresponding block via the adhesive member and a beam part that supports the stopper part and that protrudes under the corresponding block; the method comprising: a step of removing an adhesive member that connects a block having a pattern to be exchanged, in order to remove the block; a step of placing a new block on a beam part of a supporting part corresponding to the removed block; and a step of adhesively connecting the stopper part of the supporting part corresponding to the removed block and the new block by means of an adhesive member. 
     According to the above method, a pattern exchanging operation of a transfer mask for exposure can be carried out practically and easily. 
     The adhesive member can be removed by an ashing process, for example. 
     In addition, the present invention is a manufacturing method of a transfer mask for exposure, the transfer mask for exposure including a mask portion having a plurality of cells, each of which an opening of a predetermined pattern is formed in, wherein the mask portion has one or more blocks, each of which contains one or more cells, the mask portion has one or more supporting parts that supports the one or more blocks, the mask portion has one or more adhesive members that adhesively connects the one or more blocks and the one or more supporting parts and are capable of being removed at any time, and each of the supporting parts contains a stopper part that positions the corresponding block via the adhesive member, and a beam part that supports the stopper part and that protrudes under the corresponding block, the method comprising: a step of forming the plurality of cells and the stopper parts by a dry etching process; a step of forming the beam parts by both a machining process and an etching process; and a step of connecting the blocks and the stopper parts by means of the adhesive members. 
     In addition, the present invention is an exposure system comprising: a charged particle beam gun that irradiates a charged particle beam; a shaping aperture mask in which a rectangular aperture has been formed; and a transfer mask for exposure including a mask portion having a plurality of cells, each of which an opening of a predetermined pattern is formed in; wherein when one side of the plurality of cells is exposed to a charged particle beam irradiated from the charged particle beam gun through the shaping aperture mask, each of the plurality of cells is adapted to make the charged particle beam pass through itself to the other side thereof based on the pattern of the opening formed in the cell, so that when a substrate to be processed is arranged on the other side of the cell, the pattern of the opening formed in the cell is transferred to the substrate to be processed and an exposure pattern is formed on the substrate to be processed, and wherein a part of or all the plurality of cells can be exchanged at the mask portion. 
     In addition, the present invention is an exposure method using an exposure system, the exposure system including a charged particle beam gun that irradiates a charged particle beam, a shaping aperture mask in which a rectangular aperture has been formed, and a transfer mask for exposure including a mask portion having a plurality of cells, each of which an opening of a predetermined pattern is formed in, wherein when one side of the plurality of cells is exposed to a charged particle beam irradiated from the charged particle beam gun through the shaping aperture mask, each of the plurality of cells is adapted to make the charged particle beam pass through itself to the other side thereof based on the pattern of the opening formed in the cell, so that when a substrate to be processed is arranged on the other side of the cell, the pattern of the opening formed in the cell is transferred to the substrate to be processed and an exposure pattern is formed on the substrate to be processed, and wherein a part of or all the plurality of cells can be exchanged at the mask portion, the method comprising: a step of causing the charged particle beam gun to irradiate the charged particle beam through the shaping aperture mask;, and a step of exposing the one side of the plurality of cells to the charged particle beam that has been passed through the shaping aperture mask and making the charged particle beam pass through the cells to the other side of the cells, in order to transfer the pattern of the opening formed in the cell to the substrate to be processed, to form the exposure pattern on the substrate to be processed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view showing a character-projection (CP) type of electron-beam exposure system that uses a transfer mask for exposure according to an embodiment of the present invention; 
         FIG. 2  is a plan view showing a CP aperture mask according to a second embodiment of the present invention; 
         FIG. 3  is a sectional view showing the CP aperture mask according to the second embodiment of the present invention; 
         FIG. 4  is a view showing a state of the CP aperture mask according to the second embodiment of the present invention wherein a block and a stopper part are adhesively connected by adhesive members at a plurality of positions; 
         FIG. 5  is sectional views showing a surface processing step of the CP aperture mask according to the second embodiment of the present invention; 
         FIG. 6  is sectional views showing a reverse-surface processing step of the CP aperture mask according to the second embodiment of the present invention; 
         FIG. 7  is sectional views explaining block-exchanging operations of the CP aperture mask according to the second embodiment of the present invention; 
         FIG. 8  is a sectional view showing an example of dimensions of a block fixing part that makes it possible to exchange a block in order to exchange a pattern; 
         FIG. 9  is a sectional view showing another example of dimensions of a block fixing part that makes it possible to exchange a block in order to exchange a pattern; 
         FIG. 10  is a plan view showing an example of dimensions of a block and a block fixing part wherein one cell is mounted on the block; 
         FIG. 11  is a plan view showing an arrangement of blocks wherein one cell is mounted on each block and wherein a circle surrounding the blocks and the block fixing parts has a minimum diameter; 
         FIG. 12  is a plan view showing an example of dimensions of a block and a block fixing part wherein four cells are mounted on the block; 
         FIG. 13  is a plan view showing an arrangement of blocks wherein four cells are mounted on each block and wherein a circle surrounding the blocks and the block fixing parts has a minimum diameter; 
         FIG. 14  is a plan view showing an example of dimensions of a block and a block fixing part wherein sixteen cells are mounted on the block; 
         FIG. 15  is a plan view showing an arrangement of blocks wherein sixteen cells are mounted on each block and wherein a circle surrounding the blocks and the block fixing parts has a minimum diameter; 
         FIG. 16  is a plan view showing an example of dimensions of a block and a block fixing part wherein twenty-five cells are mounted on the block; 
         FIG. 17  is a plan view showing an arrangement of blocks wherein twenty-five cells are mounted on each block and wherein a circle surrounding the blocks and the block fixing parts has a minimum diameter; 
         FIG. 18  is a plan view showing an example of dimensions of a block and a block fixing part wherein one hundred cells are mounted on the block; 
         FIG. 19  is a plan view showing an arrangement of blocks wherein one hundred cells are mounted on each block and wherein a circle surrounding the blocks and the block fixing parts has a minimum diameter; 
         FIG. 20  is a plan view showing an example of dimensions of a block and a block fixing part wherein four hundred cells are mounted on the block; and 
         FIG. 21  is a plan view showing an example wherein blocks are arranged in a circle shape. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, embodiments of the present invention are explained with reference to the attached drawings. 
       FIG. 1  is a schematic view showing a character-projection (CP) type of electron-beam exposure system that uses a transfer mask for exposure according to an embodiment of the present invention. 
     As shown in  FIG. 1 , a shaping aperture mask  2  having a rectangular aperture  3  is arranged under an electron beam gun  1  that irradiates an electron beam. A CP aperture mask  4  having many cells  5 , each of which a character pattern is formed in, is arranged under the shaping aperture mask  2 . The CP aperture mask  4  is a transfer mask for exposure of the present embodiment. The character patterns of the respective cells  5  are widely various. A semiconductor wafer  6  to be exposed in a pattern is arranged on a stage (not shown) under the CP aperture mask  4 . 
     In the CP type of electron-beam exposure system as shown in  FIG. 1 , the electron beam EB irradiated from the electron beam gun  1  passes through the rectangular aperture  3  of the shaping aperture mask  2  to become a shaping beam SB. The shaping beam SB is selectively irradiated to a predetermined cell  5  of the CP aperture mask  4  having a predetermined character pattern, so that the shaping beam SB passes through the CP aperture mask  4  to become a beam pattern BP. The beam pattern BP is projected at a reduction onto the semiconductor wafer  6  as a pattern  7 . 
     When the above CP type of electron-beam exposure system is used, one character pattern can be exposed at one-time irradiating (exposing) step. Thus, compared with the conventional variable shape writing type that needs a lot of beam shots, writing speed can be remarkably increased. 
     Next, a CP aperture mask according to a second embodiment of the present invention, which is applicable to the above CP type of electron-beam exposure system, is explained.  FIG. 2  is a plan view showing the CP aperture mask of the second embodiment, and  FIG. 3  is a sectional view thereof. 
     The CP aperture mask  10  of the embodiment has: a mask part  11  in which four hundred cells  12  are formed; and a guide part  13  supporting the mask part  11  and functioning as a guide of a holder. Different character patterns are formed in the respective cells. 
     The mask part  11  is divided into four blocks  14  and exchangeable by every block  14 . Each block  14  has one hundred cells  12  that are arranged in a square shape. A stopper part  15  that positions the blocks  14  is provided around the blocks  14 . The stopper part  15  and the respective blocks  14  are adhesively connected by means of adhesive members  16 , which include carbon. As shown in  FIG. 3 , the stopper part  15  is supported by beam parts  17  via connecting parts  19  consisting of SiO 2 . Thus, the stopper part  15  and the beam parts  17  function as a supporting part for the blocks  14 . Herein, the adhesive members  16  are provided at the whole circumferences of the respective blocks  14 , as shown in  FIG. 2 . However, as shown in  FIG. 4 , the adhesive members  16  may be provided only at a plurality of positions around the respective blocks  14 . 
     Each block  14  consists of a film  21  made of silicon. One hundred character patterns  22  are formed in the one hundred cells  12 , respectively. The stopper part  15  and the beam parts  17  are also made of silicon. 
     The above mask part  11  may be formed from a silicon wafer by an etching process and a machining process, as explained after. 
     The shaping beam SB formed by the rectangular aperture of the shaping aperture mask is selectively irradiated to a predetermined cell  12  of the CP aperture mask  10 , so that a beam pattern is generated based on a character pattern of the cell  12 . The beam pattern is projected at a reduction onto the semiconductor wafer. 
     The number of cells provided in one CP aperture mask  10  is not limited to four hundred. In addition, as described after, the number of cells included in one block is not limited to one hundred. 
     Next, a manufacturing method of the CP aperture mask  10  is explained.  FIGS. 5(   a ) to  5 ( f ) are sectional views explaining a surface processing step in the manufacturing step of the CP aperture mask  10 .  FIGS. 6(   a ) to  6 ( e ) are sectional views explaining a reverse-surface processing step in the manufacturing step of the CP aperture mask  10 . 
     At first, with reference to  FIGS. 5(   a ) to  5 ( f ), the surface processing step is explained. 
     At first, an SOI wafer  31  is prepared. As shown in  FIG. 5(   a ), the SOI wafer  31  has a SiO 2  film  32  in the vicinity of a surface thereof. A surface Si part  31   a  and a main Si part  31   b  are separated by the SiO 2  film  32 . The total thickness of the SOI wafer  31  is about 725 μm, which is satisfactory. The thickness of the surface Si part  31   a  has to be a thickness capable of completely interrupt the electron beam, and may be 2 μm or thicker when an electron beam of about 5 eV is used. The thickness of the SiO 2  film  32  may be satisfactorily in the order of submicron, which is practically used at the present. 
     Then, as shown in  FIG. 5(   b ), a TEOS film  33  is formed on an upper surface of the surface Si part  31   a.  A photoresist film  34  is formed on the TEOS film  33 . Then, a predetermined pattern is formed in the photoresist film  34  by a photolithography process. 
     Then, as shown in  FIG. 5(   c ), the photoresist film  34  is used as a mask, and the TEOS film  33  is treated by a dry etching process. Then, as shown in  FIG. 5(   d ), the photoresist film  34  is removed by an ashing process. 
     Herein, as a patterning step, electron beam writing technique may be used as well. In the case, resist for electron beam is applied onto the TEOS film  33 , and then a pattern is formed by electron beam writing. Then, the resist for electron beam is used as a mask, and the TEOS film  33  is treated by an etching process. Then, the resist for electron beam is removed by an oxygen plasma ashing process. 
     After that, as shown in  FIG. 5(   e ), the TEOS film  33  is used as a mask while the surface Si part  31   a  is etched. Thus, a pattern  22  corresponding to  FIG. 3  is formed. At that time, the SiO 2  film  32  functions as a stopper layer. 
     After the pattern is formed, as shown in  FIG. 5(   f ), the TEOS film  33  is treated by an ashing process, and a pattern-protecting film  35  is formed. 
     Next, with reference to  FIGS. 6(   a ) to  6 ( e ), the reverse-surface processing step is explained. 
     As shown in  FIG. 6(   a ), the wafer that has been treated by the surface process step is arranged upside down. Then, as shown in  FIG. 6(   b ), a deep hole  37  is formed at a portion of the main Si part  31   b,  at which a beam part is not to be formed, by a machining process such as a drilling process or a blasting process. It is preferable that the deep hole has a depth of 500 μm or more, more preferably 600 μm or more. Then, as shown in  FIG. 6(   c ), the portion of the main Si part  31   b,  at which a beam part is not to be formed, is completely removed by a dry etching process. Thus, beam parts  17  are formed. 
     After that, as shown in  FIG. 6(   d ), the pattern-protecting film  35  is removed, and connecting portions of the block  14 , which are to be separated from the block  14 , are fixed by adhesive members  16 . After that, as shown in  FIG. 6(   e ), the SiO 2  film  32  is removed by a wet etching process while the connecting portions  19  are left. Thus, the CP aperture mask  10  having the exchangeable blocks  14  is formed in a state shown in  FIG. 3 . 
     Thus, when a mask pattern is formed on a surface by a dry etching process and the reverse surface is processed by a machining process and a (dry or wet) etching process, the CP aperture mask can be manufactured rapidly. 
     Next, a pattern exchanging method of the CP aperture mask  10  is explained with reference to  FIGS. 7(   a ) to  7 ( d ). 
     In the present embodiment, the one hundred cells  12  having the respective different character patterns form the one exchangeable block  14 . Thus, a specified pattern can be exchanged by exchanging the block  14 . 
     At first, in the CP aperture mask  10  as shown in  FIG. 3 , as shown in  FIG. 7(   a ), the adhesive members  16  of the block  14  to be exchanged are removed by an ashing process or the like. Thus, the block  14  is separated, and falls onto the beam parts  17 . 
     Then, as shown in  FIG. 7(   b ), the separated block  14  is removed. Then, as shown in  FIG. 7(   c ), a new block  14 ′ having a desired pattern is placed on the beam parts  17  while the new block  14 ′ is positioned by the stopper part  15 . In the case, the new block  14 ′ may be prepared in advance in accordance with the same manufacturing method as the above method described for the embodiment. 
     After that, as shown in  FIG. 7(   d ), the new block  14 ′ placed on the beam parts  17  and the stopper part  15  are adhesively connected by means of adhesive members. In the case, an arrangement height of the new block  14 ′ is lower than that of the original block  14  by a thickness of the connecting parts  19 . However, since the thickness of the connecting parts  19  is usually in the order of submicron, the above difference of the arrangement height between the blocks has no effect on the exposure. 
     As described above, the adhesive members  16  connecting the block  14  having a pattern to be exchanged are removed by the ashing process, the block  14  is taken out, the new block  14 ′ is placed at a position on the beam parts  17  substantially corresponding to the removed block  14  while the new block  14 ′ is positioned by the stopper part  15 , and then the new block  14 ′ and the stopper part  15  are adhesively connected by means of the adhesive members  16 , so that the block  14  is exchanged in a very practical method. That is, the pattern exchanging operation can be carried out easily. 
     Next, an example of dimensions of a block fixing part that makes it possible to exchange a block for exchanging a pattern in the above manner is explained. 
     In order to achieve the above exchanging operation of the block, the stopper part and a or more margin parts for being adhesively connected to the block have to be added, which are unnecessary for the conventional CP aperture mask. It is important to determine dimensions of the block fixing part in view of making the added parts as small as possible and taking into consideration errors in the block exchanging operation. 
     At first, a case wherein the block  14  and the stopper part  15  are adhesively connected at a plurality of positions is explained with reference to  FIG. 8 . 
     The thickness of a film (membrane)  21  that forms the block  14  is a thickness capable of interrupting the electron beam. When an electron beam of about 5 eV is used, a thickness of about 2 μm is enough. The thickness of the connecting parts  19  are satisfactorily in the order of submicron, and may be 0.2 μm taking into consideration the actual SOI wafers. 
     In addition, a:b=1:2 is satisfied taking into consideration a margin when a new block is maximally dislocated in a block exchanging operation, wherein a is a distance between the stopper part  15  and the block  14  and b is a width of an overlapped portion of the beam  17  and the block  14 . In the surface processing step, when the surface Si part is treated by a dry etching process while the TEOS film  33  is used as a mask, an undercut phenomenon (wherein an etched portion rounds under the TEOS film) may be caused at a side wall of the surface Si part. An amount of the rounding portion (an undercut amount) is about 10% (5% on one side) of the thickness of the surface Si part. In the case, since the thickness of the film  21  (surface Si part) is 2 μm, the undercut amount is about 0.2 μm. If the undercut amount is 2 to 5% of the distance a, the distance a can absorb deviation of the undercut amount. Thus, when the undercut amount is 0.2 μm, a=4 to 10 μm may be obtained. Taking that into consideration, a=5 μm is set. At that time, b=10 μm. 
     In addition, when the block  14  and the stopper  15  are adhesively connected at a plurality of positions, as shown in  FIG. 6(   e ), the SiO 2  film  32  is wet etched to form the connecting parts  19 . At that time, the etchant rounds under the stopper part  15 . Thus, a half (5 μm) of the SiO 2  film  32  at the b portion (10 μm) is etched by the rounding etchant. A width of the stopper part  15  is 50 μm when the width of the stopper part  15 :a width of the remaining SiO 2  film  32  (a width of the connecting part  19 )=5:4, to ensure strength of the stopper part  15 . 
     Next, a case wherein the block  14  and the stopper part  15  are adhesively connected at the whole circumference is explained with reference to  FIG. 9 . 
     In the case, the thickness of the membrane  21 , the thickness of the connecting parts  19 , the width of a, and the width of b are the same as those in  FIG. 8 . However, in the case, when the SiO 2  film  32  is wet etched to form the connecting parts  19 , the etchant doesn&#39;t round under the stopper part  15 . Thus, the width of the stopper  15  is different. That is, in the case, the width of the stopper  15  may be determined in such a manner that the undercut 0.2 μm of the membrane  21  corresponds to several % of the width of the stopper  15 . If the undercut 0.2 μm of the membrane  21  corresponds to 2% of the width of the stopper  15 , the width of the stopper  15  is 10 μm. When the etching rate of the wet etching process is about 0.1 μm/min, the width of the connecting part  19  can be controlled to be 8 μm or above. Thus, the strength of the stopper part can be maintained enough. 
     Next, an arrangement of the blocks  14  and dimensions thereof, in which the number of cells  12  formed in one block  14  is changed, is explained. 
     In the CP aperture mask, deflection of the electron beam has to be reduced as much as possible. For that purpose, it is preferable that the blocks  14  are arranged in such a manner that a circle (tangent circle) surrounding outermost blocks  14  in the mask portion  11  has a minimum diameter. Furthermore, it is preferable that the cells  12  are arranged in such a manner that the block  14  has a square shape, in view of facility in manufacturing a spare block and high density of arrangement of the cells  12  in the CP aperture mask. 
     Herein, taking into consideration the above point, a case is explained wherein four hundred square cells  12  are arranged in one CP aperture mask in such a manner that each block  14  has a square shape. In the following embodiments, the number of cells  12  arranged in each block  14  is 1, 4, 16, 25, 100 and 400. Each cell  12  has a square shape whose side is of 20 μm. The electron beam is □ 20 μm+α (square beam having a side of 20 μm+α), and hence a gap between adjacent cells in a block  14  is 5 μm. 
     At first, regarding a case wherein one block  14  includes one cell  12 , an example of dimensions of a block  14  and a block fixing part (a side wall surface of the stopper part  15 ) is shown in  FIG. 10 . Herein, the adhesive members  16  are provided at a plurality of positions around the block  14 . As shown in  FIG. 10 , in the case, the block  14  and the stopper part  15  form a square having a side of 110 μm. If they are arranged in a square shape, since the number of cells  12  is 400, all the blocks  14  and the block fixing parts form a square having a side of 2120 μm. At that time, the diameter of a circle surrounding all the blocks  14  and the block fixing parts is 2998.1 μm. If the squares, each of which consists of the block  14  and the stopper part  15 , are arranged in a polygon-like shape as shown in  FIG. 11 , the diameter of a tangent circle surrounding all the blocks  14  and the block fixing parts is 2536.2 μm. That is, in the case, if they are arranged in a polygon-like shape, the diameter of a tangent circle surrounding all the blocks  14  and the block fixing parts in the mask portion  11  is minimal. 
     Next, regarding a case wherein one block  14  includes four cells  12 , an example of dimensions of a block  14  and a block fixing part is shown in  FIG. 12 . Herein as well, the adhesive members  16  are provided at a plurality of positions around the block  14 . As shown in  FIG. 12 , in the case, the block  14  and the stopper part  15  form a square having a side of 135 μm. If they are arranged in a square shape, since the number of cells  12  is 400, all the blocks  14  and the block fixing parts form a square having a side of 1270 μm. At that time, the diameter of a circle surrounding all the blocks  14  and the block fixing parts is 1796.1 μm. If the squares, each of which consists of the block  14  and the stopper part  15 , are arranged in a polygon-like shape as shown in  FIG. 13 , the diameter of a tangent circle surrounding all the blocks  14  and the block fixing parts is 1573.9 μm. That is, in the case too, if they are arranged in a polygon-like shape, the diameter of a tangent circle surrounding all the blocks  14  and the block fixing parts in the mask portion  11  is minimal. In  FIG. 12 , the adhesive members are omitted. 
     Next, regarding a case wherein one block  14  includes sixteen cells  12 , an example of dimensions of a block  14  and a block fixing part is shown in  FIG. 14 . Herein as well, the adhesive members  16  are provided at a plurality of positions around the block  14 . As shown in  FIG. 14 , in the case, the block  14  and the stopper part  15  form a square having a side of 185 μm. If they are arranged in a square shape, since the number of cells  12  is 400, all the blocks  14  and the block fixing parts form a square having a side of 845 μm. At that time, the diameter of a circle surrounding all the blocks  14  and the block fixing parts is 1195 μm. If the squares, each of which consists of the block  14  and the stopper part  15 , are arranged in a polygon-like shape as shown by a dotted line in  FIG. 15 , the diameter of a tangent circle surrounding all the blocks  14  and the block fixing parts is 1219.5 μm. That is, in the case, if they are arranged in a square shape, the diameter of a tangent circle surrounding all the blocks  14  and the block fixing parts in the mask portion  11  is minimal. In  FIG. 14 , the adhesive members are omitted. 
     Next, regarding a case wherein one block  14  includes twenty-five cells  12 , an example of dimensions of a block  14  and a block fixing part is shown in  FIG. 16 . Herein as well, the adhesive members  16  are provided at a plurality of positions around the block  14 . As shown in  FIG. 16 , in the case, the block  14  and the stopper part  15  form a square having a side of 210 μm. If they are arranged in a square shape, since the number of cells  12  is 400, all the blocks  14  and the block fixing parts form a square having a side of 760 μm. At that time, the diameter of a circle surrounding all the blocks  14  and the block fixing parts is 1074.8 μm. If the squares, each of which consists of the block  14  and the stopper part  15 , are arranged in a polygon-like shape as shown by a dotted line in  FIG. 17 , the diameter of a tangent circle surrounding all the blocks  14  and the block fixing parts is 1187.1 μm. That is, in the case too, if they are arranged in a square shape, the diameter of a tangent circle surrounding all the blocks  14  and the block fixing parts in the mask portion  11  is minimal. In  FIG. 16 , the adhesive members are omitted. 
     Next, regarding a case wherein one block  14  includes one hundred cells  12 , an example of dimensions of a block  14  and a block fixing part is shown in  FIG. 18 . Herein as well, the adhesive members  16  are provided at a plurality of positions around the block  14 . As shown in  FIG. 18 , in the case, the block  14  and the stopper part  15  form a square having a side of 335 μm. If they are arranged in a square shape, since the number of cells  12  is 400 and the number of blocks  14  is four, all the blocks  14  and the block fixing parts form a square having a side of 590 μm. At that time, the diameter of a circle surrounding all the blocks  14  and the block fixing parts is 834.4 μm. In the case, it is clear that when they are arranged in a square shape as described above, the diameter of a tangent circle surrounding all the blocks  14  and the block fixing parts in the mask portion  11  is minimal. In  FIG. 18 , the adhesive members are omitted. 
     Next, regarding a case wherein one block  14  includes four hundred cells  12 , an example of dimensions of a block  14  and a block fixing part is shown in  FIG. 20 . Herein as well, the adhesive members  16  are provided at a plurality of positions around the block  14 . As shown in  FIG. 20 , in the case, the block  14  and the stopper part  15  form a square having a side of 505 μm. At that time, the diameter of a circle surrounding all the blocks  14  and the block fixing parts is 714.2 μm. In  FIG. 20 , the adhesive members are omitted. 
     The above results are shown together in the following Table 1. 
     
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 SIDE OF 
                 TANGENT CIRCLE 
                 TANGENT CIRCLE 
                 MINIMAL 
               
               
                   
                 SQUARE 
                 DIAMETER OF 
                 DIAMETER OF 
                 TANGENT 
               
               
                   
                 ARRANGE 
                 SQUARE 
                 POLYGON-LIKE 
                 CIRCLE 
               
               
                   
                 MENT(μm) 
                 ARRANGEMENT(μm) 
                 ARRANGEMENT(μm) 
                 DIAMETER(μm) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 1CELL/BLOCK 
                 2120 
                 2998 
                 2536 
                 2536 
               
               
                 4CELL/BLOCK 
                 1270 
                 1796 
                 1574 
                 1574 
               
               
                 16CELL/BLOCK 
                 845 
                 1195 
                 1220 
                 1195 
               
               
                 25CELL/BLOCK 
                 760 
                 1075 
                 1187 
                 1075 
               
               
                 100CELL/BLOCK 
                 590 
                 834 
                 — 
                 834 
               
               
                 400CELL/BLOCK 
                 505 
                 714 
                 — 
                 714 
               
               
                   
               
             
          
         
       
     
     As shown in Table 1, as the number of cells included in one block is increased, the diameter of a minimal tangent circle is decreased, that is, a deflection difference of the electron beam is decreased. In addition, handling characteristics are also improved. In view of those points, 25, 100 or 400 cells/block are preferable. Taking into consideration practical handling characteristics, 100 or 400 cells/block are preferable. However, as the number of cells included in one block is increased, the number of cells exchanged at one time is also increased. That is, more cells unnecessary to be exchanged may be exchanged. Then, the merits of exchange by each block may be reduced. In view of that point, 400 cells/block is inferior in the merits of exchange by each block. Thus, taking into consideration all the above aspects, 100 cells/block is most preferable. 
     In the above examples, the block  14  is formed by arranging the square cells  12  in a square shape. However, rectangular cells other than square cells may be arranged in a substantially square shape. In addition, the shape of each cell is not limited to the rectangular shape, but may be any shape. It is unnecessary that the number of cells in each block is common. In addition, the cell arrangement in one block is not limited to in the square shape. For example, the same number of cells  12  is respectively arranged in a vertical direction and in a horizontal direction, in one block  14 , in the above embodiments. However, the number of cells  12  may be different between in a vertical direction and in a horizontal direction. 
     In addition, if the mask portion  11  is circle, a distance from the center thereof to an outer circumference thereof is always constant. Thus, the deflection distance of the electron beam is thought to become the least. Thus, as shown in  FIG. 21 , it may be thought that the mask portion  11  is formed in a substantially circle shape, a circle block  14   a  is arranged at a center of the mask portion  11  and nine sectoral blocks  14   b  are arranged around the circle block  14   a.    
     The present invention is not limited to the above embodiments, but may be variously modified. For example, in the above embodiments, the mask portion is made from a SOI wafer. However, this invention is not limited thereto. In addition, in the above embodiments, the stopper part and the block are adhesively connected by the adhesive members including carbon, and the adhesive members are removed by an ashing process at an exchanging step. However, other adhesive members that can be removed by another method, for example by means of a medicament, may be also used.