Abstract:
A pattern formation method according to one embodiment includes: depositing a first C-containing film and a first inorganic layer pattern above a workpiece, the first inorganic layer pattern being comprised of linear patterns arranged in parallel and having a longitudinal direction in a predetermined direction; depositing a second C-containing film and a second inorganic layer pattern above the first C-containing film and the first inorganic layer pattern, at least a portion of the second inorganic layer pattern being comprised of linear patterns arranged in parallel and intersecting with the first inorganic layer pattern; removing the first and second C-containing films other than regions located substantially directly below at least one of the first and second inorganic layer patterns by etching, to form an etching mask including the first and second inorganic layer patterns and the etched first and second C-containing films; and forming a pattern of the workpiece by etching the workpiece using the etching mask.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2008-003450, filed on Jan. 10, 2008, the entire contents of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    A conventional pattern formation method using a photolithographic method is known in which a microscopic rectangular pattern is formed on a workpiece by forming a first mask layer composed of plural linear members arranged in parallel on a workpiece to be etched, then, forming a second mask layer composed of plural linear members arranged in parallel in a direction orthogonal to the first mask layer on the workpiece and the first mask layer, and etching the workpiece using the first and second mask layers as a mask. This technique, for example, is disclosed in JP-A-2000-357736 and JP-A-2003-188252. 
         [0003]    However, according to these methods, since the mask is mainly composed of an inorganic material, it is difficult to completely remove the mask from the workpiece, thus, it may adversely affect processes after the pattern formation. In detail, there may occur a problem in that, for example, an aspect ratio of a concave portion is increased by the mask remaining on the workpiece, resulting that it becomes difficult to form a member of an upper layer. 
       BRIEF SUMMARY 
       [0004]    A pattern formation method according to one embodiment includes: depositing a first C-containing film and a first inorganic layer pattern above a workpiece, the first inorganic layer pattern being comprised of linear patterns arranged in parallel and having a longitudinal direction in a predetermined direction; depositing a second C-containing film and a second inorganic layer pattern above the first C-containing film and the first inorganic layer pattern, at least a portion of the second inorganic layer pattern being comprised of linear patterns arranged in parallel and intersecting with the first inorganic layer pattern; removing the first and second C-containing films other than regions located substantially directly below at least one of the first and second inorganic layer patterns by etching, to form an etching mask including the first and second inorganic layer patterns and the etched first and second C-containing films; and forming a pattern of the workpiece by etching the workpiece using the etching mask. 
         [0005]    A pattern formation method according to another embodiment includes: depositing a C-containing film and an inorganic film pattern above a workpiece, the inorganic film pattern being comprised of linear patterns arranged in parallel and having a longitudinal direction in a predetermined direction; forming trenches by etching the C-containing film other than regions located substantially directly below the inorganic film pattern; forming an inorganic film in the trenches and above the inorganic film pattern; forming a resist pattern above the inorganic film, at least a portion of the resist pattern being comprised of linear patterns arranged in parallel and intersecting with the inorganic film pattern; removing, by etching, a portion of the inorganic film pattern located other than substantially directly below the resist pattern and a portion of the inorganic film located other than substantially directly below the resist pattern as well as located outside the trenches; removing the C-containing film other than regions located substantially directly below at least one of the etched inorganic film pattern and the etched inorganic film by etching, to form an etching mask including the inorganic film pattern, the inorganic film and the etched C-containing film; and forming a pattern of the workpiece by etching the workpiece using the etching mask. 
         [0006]    A pattern formation method according to another embodiment includes: depositing a C-containing film and an inorganic film pattern above a workpiece, the inorganic film pattern being comprised of linear patterns arranged in parallel and having a longitudinal direction in a predetermined direction in a region above a first region of the workpiece; forming trench as by etching the C-containing film other than regions located substantially directly below the inorganic film pattern; forming an inorganic film in the trenches and above the inorganic film pattern; forming, above the inorganic film, a resist pattern including a first pattern in the region above the first region of the workpiece and a second pattern in a region above a second region of the workpiece, at least a portion of the first pattern being comprised of linear patterns arranged in parallel and intersecting with the inorganic film pattern; removing, by etching, a portion of the inorganic film pattern located other than substantially directly below the resist pattern and a portion of the inorganic film located other than substantially directly below the resist pattern as well as located outside the trenches; removing the C-containing film other than regions located substantially directly below at least one of the etched inorganic film pattern and the etched inorganic film by etching, to form an etching mask including the inorganic film pattern, the inorganic film and the etched C-containing film; and forming a pattern of the workpiece by etching the workpiece using the etching mask. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0007]      FIGS. 1A and 1B  are a perspective view and a top view of a mask pattern in a first embodiment; 
           [0008]      FIGS. 2A to 2K  are perspective views showing a method of fabricating an etching mask in the first embodiment; 
           [0009]      FIGS. 3A and 3B  are top views showing a modification of the etching mask in the first embodiment; 
           [0010]      FIGS. 4A and 4B  are a perspective view and a top view of a mask pattern in a second embodiment; 
           [0011]      FIGS. 5A to 5H  are perspective views showing a method of fabricating an etching mask in the second embodiment; 
           [0012]      FIGS. 6A and 6B  are top views showing a modification of the etching mask in the second embodiment; and 
           [0013]      FIGS. 7A to 7D  are perspective views showing a method of fabricating the etching mask shown in  FIG. 6B . 
       
    
    
     DETAILED DESCRIPTION  
     First Embodiment 
     (Structure of Etching Mask) 
       [0014]      FIGS. 1A and 1B  are a perspective view and a top view of an etching mask in a first embodiment. 
         [0015]    An etching mask  1  is formed on a workpiece  2  to which a pattern of the etching mask  1  is transferred. The etching mask  1  has a first pattern portion  10  and a second pattern portion  20 . The first pattern portion  10  is composed of plural plate-like members, which are arranged in parallel to each other and have longitudinal directions in a first direction D 1 , and has a first pattern which is composed of plural linear patterns, which are arranged in parallel to each other and have longitudinal directions in the first direction D 1 . The second pattern portion  20  is composed of plural plate-like members, which are arranged in parallel to each other and have longitudinal directions in a second direction D 2  different from the first direction D 1  (e.g., an orthogonal direction), and has a second pattern which is composed of plural linear patterns, which are arranged in parallel to each other and have longitudinal directions in the second direction D 2 . 
         [0016]    In other words, the etching mask  1  has a cross pattern composed of the first pattern of the first pattern portion  10  and the second pattern of the second pattern portion  20  crossing each other. 
         [0017]    The first pattern portion  10  has a first C-containing layer  11  located on the workpiece  2  and a first inorganic layer  12  located on the first C-containing layer  11 . 
         [0018]    The second pattern portion  20  has a second C-containing layer  21   a  located on the workpiece  2 , a second C-containing layer  21   b  located on the second C-containing layer  21   a  and a second inorganic layer  22  located on the second C-containing layer  21   b.    
         [0019]    The first C-containing layer  11  of the first pattern portion  10  and the second C-containing layer  21   a  of the second pattern portion  20  are made of a material containing C such as a carbon film or a resist film, etc., and are formed integrally. Furthermore, the second C-containing layer  21   b  of the second pattern portion  20  is made of a material containing C such as a carbon film or a resist film, etc., and preferably made of the same material as the first C-containing layer  11  and the second C-containing layer  21   a.    
         [0020]    The first inorganic layer  12  and the second inorganic layer  22  are formed of an inorganic material such as SiO 2 , SiN or amorphous Si, etc. 
         [0021]    The etching mask  1  has plural openings  3  which are formed by combining the first pattern portion  10  and the second pattern portion  20 . A dimension and a horizontal to vertical ratio, etc., of the opening  3  can be adjusted by varying a width and a pitch (an arrangement interval) of the first pattern portion  10  and the second pattern portion  20 . Alternatively, the first pattern of the first pattern portion  10  and the second pattern of the second pattern portion  20  are not necessarily linear, and the opening  3  may be in a shape other than a rectangular, e.g., a shape in which each side is a curved line. 
         [0022]    The workpiece  2  is, e.g., an interlayer insulation film of a semiconductor device, and it is possible to form a pattern thereon that becomes a contact hole or a via hole by etching using the etching mask  1 . 
         [0023]    An example of a method of fabricating the etching mask  1  in the embodiment will be described hereinafter. 
       (Pattern Formation Method) 
       [0024]      FIGS. 2A to 2K  are perspective views showing a method of fabricating an etching mask in the first embodiment. 
         [0025]    Firstly, as shown in  FIG. 2A , a first C-containing film  30  and a first inorganic film  31  are deposited on the workpiece  2 , and then, a first resist  32  having the first pattern is formed thereon. 
         [0026]    Here, the first C-containing film  30  is a film to be shaped into the first C-containing layer  11  of the first pattern portion  10  and the second C-containing layer  21   a  of the second pattern portion  20  in a subsequent process, and is formed, e.g., 300 nm in thickness by a CVD (Chemical Vapor Deposition) method. Meanwhile, the first inorganic film  31  is a film to be shaped into the first inorganic layer  12  of the first pattern portion  10 , and is formed, e.g., 50 nm in thickness by a SOG (Spin on glass) method. And the first resist  32  is patterned using a photolithographic method, etc., and has, e.g., a thickness of 100 nm. 
         [0027]    Next, as shown in  FIG. 2B , RIE (Reactive Ion Etching), etc., is applied to the first inorganic film  31  using the first resist  32  as a mask and the first pattern of the first resist  32  is transferred to the first inorganic film  31 , which results in that the first inorganic film  31  is shaped into the first inorganic layer  12 . Here, when the first inorganic film  31  is an SiO 2  film, for example, a mixed gas of CHF 3  and O 2  is used as an etching gas at a CHF 3 /O 2  flow rate of 100/10 sccm. 
         [0028]    Next, as shown in  FIG.2C , the first resist  32  is removed by the RIE, etc. At this time, an exposed portion on the surface of the first C-containing film  30  may be abraded. Here, as an etching gas of the first resist  32 , for example, a mixed gas of O 2  and N 2  is used at an O 2 /N 2  flow rate of 100/50 sccm. Note that, although the first resist  32  is not necessarily removed, it is possible to facilitate embedding of a second C-containing film  33  in a subsequent process by removing the first resist  32  and decreasing an aspect ratio of a trench between the first inorganic layers  12 . 
         [0029]    Next, as shown in  FIG. 2D , the second C-containing film  33  is formed on the first C-containing film  30  and the first inorganic layers  12 . Here, the second C-containing film  33  is a film to be shaped into the second C-containing layer  21   b  of the second pattern portion  20  in a subsequent process, and is formed, e.g., 100 nm in thickness from the upper surface of the first inorganic layer  12  by the CVD method, etc. Meanwhile, since the second C-containing film  33  formed in the trenches between the first inorganic layers  12  are removed in a subsequent process, the second C-containing film  33  is not necessarily perfectly embedded into the trenches, for example, voids may be included. 
         [0030]    Next, as shown in  FIG. 2E , a second inorganic film  34  is formed on the second C-containing film  33 . Here, the second inorganic film  34  is a film to be shaped into the second inorganic layer  22  of the second pattern portion  20  in a subsequent process, and is formed, e.g., 50 nm in thickness by the SOG method, etc. And then, unevenness due to the second C-containing film  33  is reduced by forming the second inorganic film  34 , and it is possible to form a second resist  35  on a more flattened surface in a subsequent process. 
         [0031]    Next, as shown in  FIG. 2F , a second resist  35  having the second pattern is formed on the second inorganic film  34 . Here, the second resist  35  is patterned using the photolithographic method, etc., and has, e.g., a thickness of 100 nm. 
         [0032]    Next, as shown in  FIG. 2G , the RIE, etc., is applied to the second inorganic film  34  using the second resist  35  as a mask and the second pattern of the second resist  35  is transferred to the second inorganic film  34 , which results in that the second inorganic film  34  is shaped into the second inorganic layer  22 . Here, when the second inorganic film  34  is an SiO 2  film, for example, a mixed gas of CHF 3  and O 2  is used as an etching gas at a CHF 3 /O 2  flow rate of 100/10 sccm. 
         [0033]    Next, as shown in  FIG. 2H , the second pattern is transferred by applying the RIE, etc. to the second C-containing film  33  using the second resist  35  and the second inorganic layer  22  as a mask. Here, at least a portion of the second pattern intersects with the first pattern. The second resist  35  may be removed in this process as shown in the figure. 
         [0034]    As shown in  FIG. 2I , the etching is further continued so that the second C-containing film  33  is shaped into the second C-containing layer  21   b  and the first C-containing film  30  is shaped into the first C-containing layer  11  and the second C-containing layer  21   a.  At this time, the first inorganic layer  12  also functions as a mask, and the first and second patterns of the first inorganic layer  12  and the second inorganic layer  22  are transferred to the first C-containing film  30 . 
         [0035]    Here, as an etching gas of the second C-containing film  33  and the first C-containing film  30  in the processes shown in  FIGS. 2H and 2I , for example, a mixed gas of O 2  and N 2  is used at an O 2 /N 2  flow rate of 100/50 sccm. 
         [0036]    The etching mask  1  shown in  FIGS. 1A and 1B  is obtained by the above processes. 
         [0037]    Next, as shown in  FIG. 2J , the workpiece  2  is etched using the etching mask  1  as a mask, and a cross pattern of the etching mask I composed of the first and second patterns is transferred to the workpiece  2 . 
         [0038]    Next, as shown in  FIG. 2K , the first C-containing layer  11 , the second C-containing layers  21   a  and  21   b  are etched for separating the etching mask  1  from the workpiece  2 . Here, O 2  containing gas such as O 2  gas, etc., can be used as an etchant. 
       (Effects of the First Embodiment) 
       [0039]    According to the etching mask  1  in the first embodiment, by combining the first pattern portion  10  having the first pattern and the second pattern portion  20  having the second pattern, it is possible to form the microscopic openings  3  of which shape control is difficult by a single layer etching mask. 
         [0040]    Furthermore, since a portion located immediately above the workpiece  2  is composed of the first C-containing layer  11  and the second C-containing layer  21   a  each formed of materials containing C, it is possible to easily separate from the workpiece  2  using O 2  gas, etc., resulting that adverse effects on a subsequent process can be reduced. 
         [0041]    Note that, the etching mask  1  is not limited to the shape shown in  FIGS. 1A and 1B , it may be formed in different shapes by the above-mentioned fabrication method.  FIGS. 3A and 3B  are top views showing a modification of the etching mask  1 . As shown in  FIG. 3A , it is possible to vary a mask pattern by changing a shape or an arrangement, etc., of the first pattern portion  10  or the second pattern portion  20 . Alternatively, as shown in  FIG. 3B , the etching mask  1  may have a non-microscopic region  1   b  having a non-microscopic opening  3   b  for forming an alignment mark or a dummy pattern, etc., besides a microscopic region  1   a  having microscopic openings  3   a  for, e.g., contact plugs or via plugs, formed by combining the first pattern portion  10  and the second pattern portion  20 . Note that, the region of the etching mask  1  shown in  FIGS. 1A and 1B  corresponds to the microscopic region  1   a  shown in  FIG. 3B . 
       Second Embodiment 
       [0042]    The second embodiment is different from the first embodiment in the structure and the fabrication method of the etching mask  1 . 
       (Structure of Etching Mask) 
       [0043]      FIGS. 4A and 4B  are a perspective view and a top view of a mask pattern in a second embodiment. 
         [0044]    An etching mask  1  is formed on a workpiece  2  to which a pattern of the etching mask  1  is transferred. The etching mask  1  has a first pattern portion  10  and a second pattern portion  20 . The first pattern portion  10  is composed of plural plate-like members, which are arranged in parallel to each other and have longitudinal directions in a first direction D 1 , and has a first pattern which is composed of plural linear patterns, which are arranged in parallel to each other and have longitudinal directions in the first direction D 1 . The second pattern portion  20  is composed of plural plate-like members, which are arranged in parallel to each other and have longitudinal directions in a second direction D 2  different from the first direction D 1  (e.g., an orthogonal direction), and has a second pattern which is composed of plural linear patterns, which are arranged in parallel to each other and have longitudinal directions in the second direction D 2 . 
         [0045]    In other words, the etching mask  1  has a cross pattern composed of the first pattern of the first pattern portion  10  and the second pattern of the second pattern portion  20  crossing each other. 
         [0046]    The first pattern portion  10  has a first C-containing layer  13  located on the workpiece  2  and a first inorganic layer  14  located on the first C-containing layer  13 . 
         [0047]    The second pattern portion  20  has a second C-containing layer  23  located on the workpiece  2  and second inorganic layers  24   a  and  24   b  located on the second C-containing layer  23 . 
         [0048]    The first C-containing layer  13  of the first pattern portion  10  and the second C-containing layer  23  of the second pattern portion  20  are made of a material containing C such as a carbon film or a resist film, etc., and are formed integrally. 
         [0049]    The first inorganic layer  14  of the first pattern portion  10  and the second inorganic layer  24   b  of the second pattern portion  20  are made of an inorganic material such as SiO 2  or SOG, etc., and are formed integrally. On the other hand, the second inorganic layer  24   a  of the second pattern portion  20  is made of an inorganic material such as SiO 2 , SiN or amorphous Si, etc., and preferably made of the same material as the first inorganic layer  14  and the second inorganic layer  24   b.    
         [0050]    The etching mask  1  has plural openings  3  which are formed by combining the first pattern portion  10  and the second pattern portion  20 . A dimensions and a horizontal to vertical ratio, etc., of the opening  3  can be adjusted by varying a width and a pitch (an arrangement interval) of the first pattern portion  10  and the second pattern portion  20 . Alternatively, the opening  3  may not be a rectangular, and it may be a shape in which each side is a curved line. 
         [0051]    The workpiece  2  is, e.g., an interlayer insulation film of a semiconductor device, and it is possible to form a pattern thereon that becomes a contact hole or a via hole by etching using the etching mask  1 . 
         [0052]    An example of a method of fabricating the etching mask  1  in the embodiment will be described hereinafter. Note that, the explain will be omitted for the points which are same as the first embodiment. 
       (Pattern Formation Method) 
       [0053]      FIGS. 5A to 5H  are perspective views showing a method of fabricating an etching mask in the second embodiment. 
         [0054]    Firstly, as shown in  FIG. 5A , the processes until the process, shown in  FIG. 2B , for transferring the first pattern to the first inorganic film are carried out in the same way as the first embodiment. However, in the embodiment, an obtained first inorganic film pattern  31 ′ will be shaped into a second inorganic layer  24   a  of the second pattern portion  20  in a subsequent process, and unlike the first inorganic layer  12  shown in  FIG. 2B , it is not a constituent element of the first pattern portion  10 . 
         [0055]    Next, as shown in  FIG. 5B , the first resist  32  is removed by the RIE, etc. At this time, an exposed portion on a surface of the first C-containing film  30  is abraded at the same moment up to a predetermined depth for forming trenches  30   a.  The depth of the trench  30   a  formed on the first C-containing film  30  determines a thickness of the first inorganic layer  14  of the first pattern portion  10  which will be formed in a subsequent process, e.g., 100 nm. Here, as an etching gas of the first resist  32 , for example, a mixed gas of O 2  and N 2  is used at an O 2 /N 2  flow rate of 100/50 sccm. 
         [0056]    Next, as shown in  FIG. 5C , a second inorganic film  36  is formed on the first C-containing film  30  and the first inorganic film pattern  31 ′. Here, the second inorganic film  36  is a film to be shaped into the first inorganic layer  14  of the first pattern portion  10  and the second inorganic layer  24   b  of the second pattern portion  20  in a subsequent process, and is formed, e.g., 50 nm in thickness from the upper surface of the first inorganic film pattern  31 ′ by the SOG method, etc. In addition, since the second inorganic film  36  is etched together with the first inorganic film pattern  31 ′ in a subsequent process, it is preferable that the second inorganic film  36  is formed of the same material as the first inorganic film pattern  31 ′. 
         [0057]    Next, as shown in  FIG. 5D , an anti-reflection film  37  is formed on the second inorganic film  36  and a second resist  38  having the second pattern are formed thereon. Here, the anti-reflection film  37  is formed, e.g., 60 nm in thickness. And then, unevenness due to the second inorganic film  36  is reduced by forming the anti-reflection film  37 , and it is possible to form the second resists  38  on a more flattened surface in a subsequent process. Then, the second resist  38  is patterned using the photolithographic method, etc., and has, e.g., a thickness of 100 nm. 
         [0058]    Next, as shown in  FIG. 5E , the RIE, etc., is applied to the anti-reflection film  37 , the first inorganic film pattern  31 ′ and the second inorganic film  36  using the pattern of the second resist  38  as a mask and the second pattern of the second resist  38  is transferred, which results in that the first inorganic film pattern  31 ′ is shaped into the second inorganic layer  24   a  and the second inorganic film  36  is shaped into the second inorganic layer  24   b.  Here, a portion of the first inorganic film pattern  31 ′ that is not masked by the second resist  38  (a portion located other than substantially directly below the pattern of the second resist  38 ) is almost completely removed. As for a portion of the second inorganic film  36  that is not masked by the second resist  38  (a portion located other than substantially directly below the pattern of the second resist  38 ), at least a portion located outside of the trenches  30   a  is removed so that the second inorganic film  36  remains in the trenches  30   a.  Especially, it is preferable to etch up to the depth of a border between the first inorganic film pattern  31 ′ and the first C-containing film  30 . Meanwhile, when the first inorganic film pattern  31 ′ and the second inorganic film  36  are SiO 2  films, for example, a mixed gas of CHF 3  and O 2  is used as an etching gas at a CHF 3 /O 2  flow rate of 100/10 sccm. 
         [0059]    Next, as shown in  FIG. 5F , the RIE, etc., is applied to the first C-containing film  30  using the pattern of the second resist  38 , the second inorganic layer  24   b  and the first inorganic layer  14  as a mask, and the first and second patterns are transferred to the first C-containing film  30 , which results in that the first C-containing film  30  is shaped into the first C-containing layer  13  and the second C-containing layer  23 . Note that, as shown in the figure, the second resists  38  and the anti-reflection film  37  may be removed in this process. Here, as an etching gas of the first C-containing film  30 , for example, a mixed gas of O 2  and N 2  is used at an O 2 /N 2  flow rate of 100/50 sccm. 
         [0060]    The etching mask  1  shown in  FIGS. 4A and 4B  is obtained by the above processes. 
         [0061]    Next, as shown in  FIG. 5G , the workpiece  2  is etched using the etching mask  1  as a mask, and a pattern of the etching mask  1  is transferred to the workpiece  2 . 
         [0062]    Next, as shown in  FIG. 5H , the first C-containing layer  13  and the second C-containing layer  23  are etched for separating the etching mask  1  from the workpiece  2 . Here, O 2  containing gas such as O 2  gas, etc., can be used as an etchant. 
       (Effects of the Second Embodiment) 
       [0063]    According to the etching mask  1  in the second embodiment, since only one layer of a C-containing film (only the first C-containing film  30 ) is used as a material, it is possible to reduce the processes compared with the first embodiment. 
         [0064]    In addition, unlike the first embodiment, since two inorganic films (the first inorganic film pattern  31 ′ and the second inorganic film  36 ) are formed as continuous films that contact each other, it is possible to carry out the shaping and the removal continuously in the same process (e.g., when the second pattern is remade after the photolithography), hence, it is possible to reduce the processes compared with the first embodiment. 
         [0065]    Note that, the etching mask  1  is not limited to the shape shown in  FIGS. 4A and 4B , it may be formed in different shapes by the above-mentioned fabrication method.  FIGS. 6A and 6B  are top views showing a modification of the etching mask  1 . As shown in  FIG. 6A , it is possible to vary a mask pattern by changing a shape or an arrangement, etc., of the first pattern portion  10  or the second pattern portion  20 . Alternatively, as shown in  FIG. 6B , the etching mask  1  may have a non-microscopic region  1   b  having a non-microscopic opening  3   b  for forming an alignment mark or a dummy pattern, etc., besides a microscopic region  1   a  having microscopic openings  3   a  formed by combining the first pattern portion  10  and the second pattern portion  20 . Note that, the region of the etching mask  1  shown in  FIGS. 4A and 4B  corresponds to the microscopic region  1   a  shown in  FIG. 6B . 
         [0066]      FIGS. 7A to 7D  are perspective views showing a method of fabricating the etching mask  1  having the microscopic region  1   a  and the non-microscopic region  1   b  shown in  FIG. 6B . Note that,  FIGS. 7A to 7D  show cross sections when a cut surface taken on line VII-VII shown in  FIG. 6B  is viewed in a direction indicated by an arrow in the figure. 
         [0067]      FIG. 7A  corresponds to  FIG. 5D  and shows a state that a pattern of the second resist  38  has been formed. 
         [0068]      FIG. 7B  corresponds to  FIG. 5E  and shows a state that the first inorganic film pattern  31 ′ has been shaped into the second inorganic layer  24   a  and the second inorganic film  36  has been shaped into the second inorganic layer  24   b  in the microscopic region  1   a . In this process, it is possible to continuously remove two inorganic films (the first inorganic film pattern  31 ′ and the second inorganic film  36 ) in a region of the non-microscopic region  1   b  not masked by the second resist  38 . Therefore, it is not necessary to pattern the inorganic film in the non-microscopic region  1   b  by using the first resist  32 . 
         [0069]    And then, according to this, when a pattern density of the first pattern portion  10  is differed from that of the second pattern portion  20 , the pattern density of the second resist  38  in the microscopic region  1   a  is made close to that in the non-microscopic region  1   b  by roughening the density of the second pattern portion  20  than that of the first pattern portion  10 , and thus, it is possible to take a large margin for the opening  3   b.    
         [0070]    Note that, when the etching mask  1  in the first embodiment has the microscopic region  1   a  and the non-microscopic region  1   b  as shown in  FIG. 3B , since the two inorganic films (the first inorganic film  31  and the second inorganic film  36 ) are formed sandwiching another film (the second C-containing film  33 ), these films can not be continuously patterned in one process, and thus each needed to be pattern in other processes using other resists (the first resist  32  and the second resist  35 ). 
         [0071]      FIG. 7C  corresponds to  FIG. 5F  and shows a state that the first C-containing film  30  has been shaped into the first C-containing layer  13  and the second C-containing layer  23  in the microscopic region  1   a . The first C-containing film  30  in the non-microscopic region  1   b  is patterned and the opening  3   b  is formed in this process. 
         [0072]      FIG. 7D  corresponds to  FIG. 5H  and shows a state the workpiece  2  is etched using the etching mask  1  as a mask and the etching mask  1  is separated from the workpiece  2  after transferring the pattern of the etching mask  1  to the workpiece  2 . 
       Other Embodiments 
       [0073]    It should be noted that the present invention is not intended to be limited to the above-mentioned first and second embodiments, and the various kinds of changes thereof can be implemented by those skilled in the art without departing from the gist of the invention. 
         [0074]    In addition, the constituent elements of the above-mentioned embodiments can be arbitrarily combined with each other without departing from the gist of the invention.