Patent Abstract:
To include transferring simultaneously by lithography a first region from a position opposed between a first constituent member and a second constituent member in a longitudinal direction of a third constituent member to the end of a side of the first constituent member and a first mask pattern for forming the first constituent member, onto a semiconductor substrate, transferring simultaneously by lithography a second region including regions other than the first region out of the third constituent member and a second mask pattern for forming the second constituent member, onto the semiconductor substrate, and forming the first constituent member, the second constituent member, and the third constituent member on the semiconductor substrate by using the first and second mask patterns.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2008-238004, filed on Sep. 17, 2008; the entire 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 semiconductor device manufacturing method. 
         [0004]    2. Description of the Related Art 
         [0005]    With the progress of area reduction and downsizing of a semiconductor device, a highly-integrated static random access memory (SRAM) has a shortened length between gate electrodes adjacent in a longitudinal direction of the gate electrode. Recently, the demanded length has exceeded the resolution limit of a photolithography technique. Even so, as disclosed in Japanese Patent Application Laid-open No. 2004-356469, for example, a further shortened length between gate electrodes to achieve area reduction and downsizing of semiconductor devices has been required. 
         [0006]    A contact is formed between gate electrodes adjacent in a lateral direction of the gate electrode. In this case, in order that the gate electrode and the contact are not short-circuited, positions of contact holes at the time of forming the contact need to be accurately aligned between the gate electrodes. However, to achieve further area reduction and downsizing of semiconductor devices, also in a lateral direction of the gate electrode, shortening of the length between the adjacent gate electrodes has been required. This further shortens a length between the gate electrode and the contact, and it makes alignment of the contact hole more difficult. 
         [0007]    Shortening of the length between arrangement patterns described above has been required not only in gate electrodes but also required in wiring layers. Moreover, further shortening of the length between the arrangement patterns has been required. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    One aspect of this invention is to provide a manufacturing method of a semiconductor device including a semiconductor substrate that is formed thereon with: a first constituent member; a second constituent member that is extended to be separated from the first constituent member on an extension of a longitudinal direction of the first constituent member; and a third constituent member that is separated from the first constituent member and the second constituent member in a lateral direction of the first and second constituent members and that is opposed in one portion to the first and second constituent members, the manufacturing method comprising: transferring simultaneously by lithography, a first region from a position opposed between the first and second constituent members in the longitudinal direction to an end of a side of the first constituent member in the longitudinal direction in the third constituent member, and a first mask pattern for forming the first constituent member, onto a semiconductor substrate; transferring simultaneously by lithography a second region including regions other than the first region in the third constituent member and a second mask pattern for forming the second constituent member, onto the semiconductor substrate; and forming the first constituent member, the second constituent member, and the third constituent member on the semiconductor substrate by using the first mask pattern and the second mask pattern. 
         [0009]    Another aspect of this invention is to provide a manufacturing method of a semiconductor device including a semiconductor substrate that is formed thereon with: a first constituent member; a second constituent member that is extended to be separated from the first constituent member on an extension of a longitudinal direction of the first constituent member; a third constituent member that is separated from the first constituent member and the second constituent member in a lateral direction of the first and second constituent members and that is opposed in one portion to the first and second constituent members; a first contact arranged to be separated from both the first constituent member and the third constituent member in a region between the first and third constituent members; and a second contact arranged to be separated from both the second constituent member and the third constituent member in a region between the second and third constituent members, the manufacturing method comprising: transferring simultaneously by lithography, a first region from a position opposed between the first and second constituent members in the longitudinal direction to an end of a side of the first constituent member in the longitudinal direction in the third constituent member, and a first mask pattern for forming the first constituent member, onto a semiconductor substrate; transferring simultaneously by lithography a second region including regions other than the first region in the third constituent member and a second mask pattern for forming the second constituent member, onto the semiconductor substrate; forming the first constituent member, the second constituent member, and the third constituent member on the semiconductor substrate by using the first mask pattern and the second mask pattern; forming by lithography a third mask pattern for forming the first contact on the semiconductor substrate by being aligned to the first constituent member and third constituent member; forming by lithography a fourth mask pattern for forming the second contact on the semiconductor substrate by being aligned to the second constituent member and third constituent member; and forming a contact hole for forming the first contact and a contact hole for forming the second contact on the semiconductor substrate by using the third mask pattern and the fourth mask pattern. 
         [0010]    Another aspect of this invention is to provide a manufacturing method of a semiconductor device including a semiconductor substrate that is formed thereon with: a first constituent member; a second constituent member that is extended to be separated from the first constituent member on an extension of a longitudinal direction of the first constituent member; and a third constituent member that is separated from the first constituent member and the second constituent member in a lateral direction of the first and second constituent members and that is opposed in one portion to the first and second constituent members, the manufacturing method comprising: transferring simultaneously by lithography, a first region from a position opposed between the first and second constituent members in the longitudinal direction to an end of a side of the second constituent member in the longitudinal direction in the third constituent member, and a first mask pattern for forming the first constituent member, onto a semiconductor substrate; transferring simultaneously by lithography a second region including regions other than the first region in the third constituent member and a second mask pattern for forming the second constituent member, onto the semiconductor substrate; and forming the first constituent member, the second constituent member, and the third constituent member on the semiconductor substrate by using the first mask pattern and the second mask pattern. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIGS. 1A and 1B  are schematic diagrams for explaining a configuration of a semiconductor device according to a first embodiment of the present invention; 
           [0012]      FIG. 2  is a schematic diagram for explaining a semiconductor device manufacturing method according to the first embodiment; 
           [0013]      FIG. 3  is a schematic diagram for explaining the semiconductor device manufacturing method according to the first embodiment; 
           [0014]      FIG. 4  is a schematic diagram for explaining the semiconductor device manufacturing method according to the first embodiment; 
           [0015]      FIG. 5  is a schematic diagram for explaining the semiconductor device manufacturing method according to the first embodiment; 
           [0016]      FIGS. 6A and 6B  are schematic diagrams for explaining the semiconductor device manufacturing method according to the first embodiment; 
           [0017]      FIGS. 7A and 7B  are schematic diagrams for explaining the semiconductor device manufacturing method according to the first embodiment; 
           [0018]      FIGS. 8A and 8B  are schematic diagrams for explaining the semiconductor device manufacturing method according to the first embodiment; 
           [0019]      FIGS. 9A and 9B  are schematic diagrams for explaining the semiconductor device manufacturing method according to the first embodiment; 
           [0020]      FIGS. 10A and 10B  are schematic diagrams for explaining the semiconductor device manufacturing method according to the first embodiment; 
           [0021]      FIGS. 11A and 11B  are schematic diagrams for explaining the semiconductor device manufacturing method according to the first embodiment; 
           [0022]      FIGS. 12A and 12B  are schematic diagrams for explaining a semiconductor device manufacturing method according to a second embodiment of the present invention; 
           [0023]      FIGS. 13A and 13B  are schematic diagrams for explaining the semiconductor device manufacturing method according to the second embodiment; 
           [0024]      FIGS. 14A and 14B  are schematic diagrams for explaining the semiconductor device manufacturing method according to the second embodiment; 
           [0025]      FIGS. 15A and 15B  are schematic diagrams for explaining the semiconductor device manufacturing method according to the second embodiment; 
           [0026]      FIGS. 16A and 16B  are schematic diagrams for explaining the semiconductor device manufacturing method according to the second embodiment; 
           [0027]      FIGS. 17A and 17B  are schematic diagrams for explaining a gate electrode in a semiconductor device according to a third embodiment of the present invention; 
           [0028]      FIG. 18  is a schematic diagram for explaining a manufacturing method of a gate electrode in the semiconductor device according to the third embodiment; 
           [0029]      FIG. 19  is a schematic diagram for explaining the manufacturing method of a gate electrode in the semiconductor device according to the third embodiment; 
           [0030]      FIGS. 20A and 20B  are schematic diagrams for explaining the manufacturing method of a gate electrode in the semiconductor device according to the third embodiment; 
           [0031]      FIGS. 21A and 21B  are schematic diagrams for explaining the manufacturing method of a gate electrode in the semiconductor device according to the third embodiment; 
           [0032]      FIGS. 22A and 22B  are schematic diagrams for explaining the manufacturing method of a gate electrode in the semiconductor device according to the third embodiment; 
           [0033]      FIGS. 23A and 23B  are schematic diagrams for explaining a wire layer in a semiconductor device according to a fourth embodiment of the present invention; and 
           [0034]      FIG. 24  is a schematic diagram for explaining a manufacturing method of a wire layer in the semiconductor device according to the fourth embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    Exemplary embodiments of a semiconductor device manufacturing method according to the present invention will be explained below in detail with reference to the accompanying drawings. The present invention is not limited to the descriptions of the following embodiments and various modifications can be appropriately made without departing from the scope of the invention. In the drawings explained below, scales of respective members may be shown differently from those in practice to facilitate understanding, and the same applies to the relationships between drawings. In addition, explanations and illustrations of constituent members not directly relevant to the present invention will be omitted. 
       First Embodiment 
       [0036]      FIGS. 1A and 1B  are schematic diagrams for explaining a part of the configuration of a semiconductor device according to a first embodiment of the present invention, that is, a highly-integrated SRAM in which six transistors are point-symmetrically laid out.  FIG. 1A  is a plan view and  FIG. 1B  is a cross-sectional view. In the semiconductor device, on a semiconductor substrate, a plurality of transistors (not shown) are arranged in device forming regions (active regions)  111 . The device forming region  111  is defined by being surrounded by device isolating regions  112 . Within the semiconductor substrate in each device forming region  111 , two impurity diffusion layers, which serve as a source and a drain of a transistor, are arranged (not shown). 
         [0037]    On the semiconductor substrate between the two impurity diffusion layers, a plurality of substantially rectangular gate electrodes  121  made of polysilicon are arranged substantially parallel via a gate insulating film (not shown) made of a silicon oxide film, and interlayer insulating films  122  are arranged over the entire surface of the semiconductor substrate so that the gate electrodes  121  are covered. Within each interlayer insulating film  122 , a plurality of contact holes A  113  and contact holes B  114  each of which conducts to the impurity diffusion layer or the gate electrode  121  are arranged.  FIGS. 1A and 1B  depict a state that the contact holes A  113  and the contact holes B  114  are formed in the interlayer insulating film  122 .  FIG. 1A  depicts a state that the interlayer insulating film  122  is provided in a transparent manner. 
         [0038]    In the first embodiment, the gate electrodes  121  adjacent in a longitudinal direction of each gate electrodes  121  (an X direction in  FIG. 1A . Hereinafter, “longitudinal direction”) are arranged on the substantially same line. A length LX 1  between the gate electrodes  121  adjacent in the longitudinal direction (the X direction in  FIG. 1A ) is set to a very short length that exceeds a resolution limit of a photolithography technique, making it very difficult to form its configuration. 
         [0039]    Between the gate electrodes  121  adjacent in a lateral direction of each gate electrode  121  (a Y direction in  FIG. 1A . Hereinafter, “lateral direction”), the contact hole A  113  or the contact hole B  114  is formed. A length between the gate electrode  121  and the contact hole A  113 , and a length LX 1  between the gate electrode  121  and the contact hole B  114  are set to a very short length that exceeds a resolution limit of a photolithography technique. This makes it very difficult to configure to form the contact hole A  113  and the contact hole B  114  at predetermined positions so that the contact formed by using the contact hole A  113  or the contact hole B  114  and the gate electrodes  121  are not short-circuited. When a length between members in an in-plane direction of a semiconductor substrate is thus set to a short length that exceeds a resolution limit of a photolithography technique, the SRAM according to the first embodiment leads to high integration of transistors, thereby realizing an SRAM with a reduced area. 
         [0040]    A highly-integrated SRAM manufacturing method according to the first embodiment is explained below with reference to  FIGS. 2 to 11B .  FIG. 2  to  FIG. 11B  are schematic diagrams for explaining the highly-integrated SRAM manufacturing method according to the first embodiment, where each drawing denoted with A is a plan view, and each drawing denoted with B is a cross-sectional view along a line A-A in each corresponding drawing denoted with A. Explanations of the formation of the gate insulating film will be omitted. First, as shown in  FIG. 2 , a design layout of an SRAM unit is extracted from a design layout of a semiconductor device, and rectangular patterns  121   p  of the gate electrodes  121  are extracted from the extracted design layout. 
         [0041]    Next, the rectangular pattern  121   p  of each of the extracted gate electrodes  121  is divided into two substantially rectangular patterns, that is, a substantially rectangular gate pattern A (hereinafter, “gate A”)  11  and gate pattern B (hereinafter, “gate B”)  12 . These patterns A and B are divided along a borderline or certain intermediate position of the longitudinal direction (an X direction in  FIG. 3 ) of each rectangular pattern, as shown in  FIG. 3 . In this way, the design layout of the gate electrode  121  is divided into two, that is, the gate A  11  and the gate B  12 . In this case, each rectangular pattern is divided into two patterns along the borderline or certain intermediate position of the longitudinal direction of each rectangular pattern, and the borderline, however, can be any position as long as it is between the other two gate electrodes  121  opposed in the lateral direction. 
         [0042]    Thereafter, in order that in each of the divided layouts, a pattern according to a design value is formed on the semiconductor substrate, there is manufactured a photomask that is formed with a gate electrode pattern corrected by using optical proximity correction (OPC). That is, two photomasks (a photomask for the gate A and a photomask for the gate B) are manufactured. At this time, the patterns for the gate A and the gate B in the photomasks are so formed that the gate A  11  and the gate B  12  are overlapped each other by several tens of nanometers in the longitudinal direction of the rectangular pattern, as shown in  FIG. 4 . 
         [0043]    Next, from the design layout of the SRAM unit, a design layout of the contact hole is extracted. In the design layout, as shown in  FIG. 5 , a square-shaped contact hole flanked between the two gates A  11  adjacent in the lateral direction (a Y direction in  FIG. 5 ) is set as a contact hole pattern A  13 . A square-shaped contact hole pattern flanked between the two gates B  12  adjacent in the lateral direction (the Y direction in  FIG. 5 ) is set as a contact hole pattern B  14 , as shown in  FIG. 5 . Thereby, the design layout of the contact hole is divided into two, that is, the contact hole pattern A  13  and the contact hole pattern B  14 . 
         [0044]    Other contact hole patterns are classified into either the contact hole pattern A  13  or the contact hole pattern B  14  depending on a process margin. Thereafter, in order that in each of the divided layouts, a pattern according to a design value is formed on the semiconductor substrate, there is manufactured a photomask that is formed with a contact hole pattern corrected by using OPC or a contact hole pattern added with an unresolved assisting pattern. That is, two photomasks (a photomask for the contact hole pattern A and a photomask for the contact hole pattern B) are manufactured. 
         [0045]    Next, as shown in  FIGS. 6A and 6B , on a main surface of the semiconductor substrate formed with the device forming regions  111  defined by being surrounded by the device isolating regions  112 , a polysilicon film  121   a  for forming gate electrodes is formed, and on top of the polysilicon film  121   a , a silicon nitride film, for example, is formed as a first hard mask film  131   a . By employing photolithography using the photomask for the gate A, a first resist patterns  132  are formed on the first hard mask film  131   a , as shown in  FIGS. 6A and 6B . Thereby, the first resist patterns  132  are formed at a position corresponding to the gate A  11  on the main surface of the semiconductor substrate. Thereafter, according to need, a process of slimming the first resist pattern  132  is performed by etching. 
         [0046]    Next, the first resist patterns  132  are used as a mask to etch the first hard mask film  131   a , and as shown  FIGS. 7A and 7B , the first hard mask patterns  131  are formed on the polysilicon film  121   a . Thereby, the first hard mask patterns  131  are formed at a position corresponding to the gates A  11 . 
         [0047]    Next, by employing photolithography using the photomask for the gates B, second resist patterns  133  are formed at a position corresponding to the gates B  12 , as shown in  FIGS. 8A and 8B . The patterns of the photomask for the gates A and the patterns of the photomask for the gates B are so formed that the both patterns are overlapped each other in the longitudinal direction of the rectangular pattern by several tens of nanometers as shown in  FIG. 4 , and thus the second resist pattern  133  is so formed that one portion thereof is overlapped with the first hard mask pattern  131 . The second resist pattern  133  is formed in a region of the rectangular pattern  121   p  (over the entire region other than a region of at least the first hard mask pattern  131 ). Thereafter, according to need, a process of slimming the second resist patterns  133  are performed by etching. 
         [0048]    Next, the first hard mask patterns  131  and the second resist patterns  133  are used as a mask to etch the polysilicon film  121   a , thereby removing the first hard mask patterns  131  and the second resist patterns  133 . As a result, the gate electrodes  121  are formed as shown in  FIGS. 9A and 9B . 
         [0049]    Next, formation of the interlayer insulating film  122  and a second hard mask film  134   a  on the semiconductor substrate in this order is formed out, as shown in  FIGS. 10A and 10B . A third resist film (not shown) is further formed on the semiconductor substrate. By employing photolithography using a photomask for the contact hole patterns A, a third resist patterns  135  are formed as shown in  FIGS. 10A and 10B , thereby forming the contact hole patterns A  13 . 
         [0050]    At this time, the contact hole patterns A  13 , which are aligned to the gates A  11 , is exposed. That is, the contact hole pattern A  13  is so aligned that one portion thereof is precisely overlapped over the gate A  11  of an underlayer, and the contact hole pattern A  13  are so aligned that another portion thereof is not overlapped in the gate A  11  in a region between the gates A  11  adjacent in the lateral direction. The exposure is performed in this state. Thereafter, as shown in  FIGS. 10A and 10B , the third resist patterns  135  are used as a mask to etch the second hard mask film  134   a.    
         [0051]    Next, the third resist patterns  135  are removed, and a fourth resist film (not shown) is formed on the semiconductor substrate. By employing photolithography using a photomask for the contact hole patterns B, a fourth resist patterns  136  are formed as shown in  FIGS. 11A and 11B , thereby forming the contact hole patterns B  14 . 
         [0052]    At this time, the contact hole patterns B  14 , which are aligned to the gates B  12 , is exposed. That is, the contact hole pattern B  14  is so aligned that one portion thereof is precisely overlapped over the gate B  12  of an underlayer, and the contact hole pattern B  14  is so aligned that another portion thereof is not overlapped with the gate B  12  in a region between the gates B  12  adjacent in the lateral direction. In this state, the exposure is performed. Thereafter, as shown in  FIGS. 11A and 11B , the fourth resist patterns  136  are used as a mask to etch the second hard mask film  134   a , thereby forming second hard mask patterns  134 . 
         [0053]    The fourth resist patterns  136  are then removed, and the second hard mask patterns  134  are used as a mask to etch the interlayer insulating film  122 , thereby forming the contact holes A  113  and the contact holes B  114 . As a result, the highly-integrated SRAM according to the first embodiment shown in  FIGS. 1A and 1B  is formed. 
         [0054]    As described above, in the highly-integrated SRAM manufacturing method according to the first embodiment, at the time of forming the etching mask for forming the gate electrodes  121  by using the lithography, the pattern for the gate electrodes  121  are divided into two patterns, that is, the pattern for the gates A  11  and that for the gates B  12 , so that the patterns of the same type are not faced to each other at a line end of the pattern. Thereafter, the divided patterns are arranged on two respectively different photomasks, and transferred to the etching mask over two exposing steps. That is, pattern ends of the gate electrodes  121  adjacent in the longitudinal direction are arranged, one pattern after the other, on the different photomasks, and transferred to the etching mask over two exposing steps. Thereby, even when the length LX 1  between the gate electrodes  121  adjacent in the longitudinal direction exceeds the resolution limit of a photolithography technique, it is possible to prevent deterioration in the dimensional accuracy which is caused due to the length LX 1  at the time of forming the etching mask and which is found in the exposure at a photolithography step, and possible to form a plurality of gate electrodes  121  with a favorable positioning accuracy at a desired position in the longitudinal direction. In the first embodiment, a case that the divided patterns are arranged on the two respectively different photomasks and transferred to the etching mask over the two exposing steps has been described. However, the divided patterns can be separately arranged on a single photomask and transferred to the etching mask over the two exposing steps. 
         [0055]    Further, in another highly-integrated SRAM manufacturing method according to the first embodiment, the pattern for the gate electrodes  121  in the regions overlapped in the longitudinal direction are divided, as patterns of the same type, into two, that is, the gate A  11  and the gate B  12 . The divided patterns are arranged on the two respectively different photomasks and transferred to the etching mask over the two exposing steps. The contact hole patterns A  13  arranged in a region between the gates A  11  in the lateral direction, which are directly aligned to the gates A  11  in the gate electrodes  121 , are exposed. The contact hole patterns B  14  arranged in a region between the gates B  12  in the lateral direction, which are directly aligned to the gates B  12  in the gate electrode  121 , are exposed. 
         [0056]    Accordingly, the patterns for the contact holes are directly aligned only to the pattern for the adjacent gate electrodes  121 , and thus even when the length LY 1  between the contact hole and the gate electrode  121  adjacent in the lateral direction exceeds the resolution limit of a photolithography technique, a plurality of contact holes  113  and  114  can be formed at a desired position with a favorable positioning accuracy rather than deteriorating the accuracy of precisely overlapping the gate electrode  121  on the contact hole pattern. Moreover, the patterns for the contact holes are directly aligned only to the patterns for the adjacent gate electrodes  121 , and thus, even when the length LY 1  between the contact hole and the gate electrode  121  adjacent in the lateral direction or the position of the gate electrodes  121  adjacent in the lateral direction exceeds the accuracy limit of indirect aligning, the contact holes  113  and  114  can be formed at a desired position with a favorable positioning accuracy rather than deteriorating the accuracy of precisely overlapping the gate electrode  121  on the contact hole pattern. The indirect aligning accuracy is an accuracy of aligning the pattern for a first contact hole and the pattern for a first gate electrode in a case that the pattern for the first contact hole is not individually aligned directly to the pattern for the first gate electrode adjacent in the lateral direction and the position of the pattern for the first contact hole is determined according to the alignment between a pattern for the other second contact hole and the pattern for the second gate electrode adjacent to the second contact hole in the lateral direction, for example. 
         [0057]    Therefore, in the highly-integrated SRAM manufacturing method according to the first embodiment, the length between the gate electrodes adjacent in the longitudinal direction and the length between the gate electrode and the contact hole are shortened, and at the same time, these members can be formed at a desired position with a favorable positioning accuracy. Thus, area reduction of a semiconductor device can be achieved. 
       Second Embodiment 
       [0058]    In a second embodiment of the present invention, another manufacturing method of the highly-integrated SRAM of the first embodiment shown in  FIG. 1  is described with reference to  FIGS. 12A to 16B .  FIGS. 12A to 16B  are schematic diagrams for explaining a highly-integrated SRAM manufacturing method according to the second embodiment, where each drawing denoted with A is a plan view, and each drawing denoted with B is a cross-sectional view along a line A-A in each corresponding drawing denoted with A. Explanations of the formation of the gate insulating film will be omitted. 
         [0059]    First, according to the steps described in the first embodiment with reference to  FIGS. 2 to 5 , the photomask for the gates A, the photomask for the gates B, the photomask for the contact hole patterns A, and the photomask for the contact hole patterns B are manufactured. 
         [0060]    Next, as show in  FIGS. 12A and 12B , on a main surface of the semiconductor substrate formed with the device forming regions  111  defined by being surrounded by the device isolating regions  112 , the polysilicon film  121   a  for forming gate electrodes is formed, and on top of the polysilicon film  121   a , a silicon nitride film, for example, is formed as a first hard mask film  141   a . On top of the first hard mask film  141   a , a silicon oxide film, for example, is formed as a second hard mask film  142   a . By employing photolithography using the photomask for the gates A, first resist patterns  143  are formed on the second hard mask film  142   a , as shown in  FIGS. 12A and 12B . Thereby, the first resist patterns  143  are formed at a position corresponding to the gates A  11  on the main surface of the semiconductor substrate. Thereafter, according to need, a process of slimming the first resist patterns  143  are performed by etching. 
         [0061]    Next, the first resist patterns  143  are used as a mask to etch the second hard mask film  142   a , and as shown in  FIGS. 13A and 13B , second hard mask patterns  142  are formed on the first hard mask film  141   a . Thereby, the second hard mask patterns  142  are formed at a position corresponding to the gates A  11  on the main surface of the semiconductor substrate. 
         [0062]    Next, by employing photolithography using the photomask for the gates B, second resist patterns  144  are formed at a position corresponding to the gates B  12  on the main surface of the semiconductor substrate, as shown in  FIGS. 14A and 14B . The pattern of the photomask for the gates A and the pattern of the photomask for the gates B are so formed that the both patterns are overlapped each other in the longitudinal direction of the rectangular pattern by several tens of nanometers as shown in  FIG. 4 , and thus the second resist pattern  144  is so formed that one portion thereof is overlapped with the second hard mask pattern  142 . Thereafter, according to need, a process of slimming the second resist patterns  144  are performed by etching. 
         [0063]    Next, the second hard mask patterns  142  and the second resist patterns  144  are used as a mask to etch the first hard mask film  141   a , thereby forming a first hard mask patterns  141 , as shown in  FIGS. 15A and 15B . Thereby, the first hard mask patterns  141  are formed at a position corresponding to the gates A  11  and the gates B  12  on the main surface of the semiconductor substrate. 
         [0064]    Next, the first hard mask patterns  141  are used as a mask to etch the polysilicon film  121   a , thereby forming the gate electrodes  121 , as shown in  FIGS. 16A and 16B . Thereafter, steps after the formation of the interlayer insulating film  122  ( FIGS. 10A and 10B ) in the first embodiment are implemented. As a result, the highly-integrated SRAM shown in  FIG. 1  can be formed. 
         [0065]    Also in the highly-integrated SRAM manufacturing method according to the second embodiment, the same effect as that in the first embodiment can be obtained. That is, the length between the gate electrodes adjacent in the longitudinal direction and the length between the gate electrode and the contact hole can be shortened, and at the same time, these members can be formed at a desired position with a favorable positioning accuracy. Thus, area reduction of a semiconductor device can be achieved. 
       Third Embodiment 
       [0066]    A third embodiment of the present invention describes a manufacturing method of a gate electrode in a semiconductor device.  FIGS. 17A and 17B  are schematic diagrams for explaining arrangement of a gate electrode  152  in the semiconductor device according to the third embodiment, where  FIG. 17A  is a plan view thereof, and  FIG. 17B  is a cross-sectional view thereof. In  FIGS. 17A and 17B , a plurality of substantially rectangular gate electrodes  152  (a gate electrode  152 A, a gate electrode  152 B, and a gate electrode  152 C) made of polysilicon are formed substantially parallel on a semiconductor substrate  151 . 
         [0067]    The gate electrode  152 A and the gate electrode  152 B are arranged on the substantially same line to be separated by a length LX 2  in a longitudinal direction (an X direction in  FIG. 17A . Hereinafter, “longitudinal direction”) of the gate electrode  152 . The length LX 2  is a length between the gate electrode  152 A and the gate electrode  152 B adjacent in the longitudinal direction (the X direction in  FIG. 17A ). The gate electrode  152 C is arranged to be separated by a length LY 2  in a lateral direction (a Y direction in  FIG. 17A . Hereinafter, “lateral direction”) of the gate electrode  152  relative to the gate electrode  152 A and the gate electrode  152 B and also to be overlapped with each portion of the both gate electrode  152 A and gate electrode  152 B in the longitudinal direction (the X direction in  FIG. 17A ), for example, by the substantially same length. The length LY 2  is a length between the gate electrode  152 A and the gate electrode  152 C and between the gate electrode  152 B and the gate electrode  152 C, adjacent in the lateral direction (the Y direction in  FIG. 17A ). Specifically, a gate insulating films are formed beneath the gate electrodes  152 , and device forming regions and device isolating regions are formed on the semiconductor substrate  151 . However, explanations of these constituent elements will be omitted. 
         [0068]    In the third embodiment, the length LX 2  is set to a very short length that exceeds the resolution limit of a photolithography technique, making it very difficult to form its configuration. Moreover, the length LY 2  is set to a very short length that exceeds the resolution limit of a photolithography technique, making it very difficult to form its configuration. By having such a layout, the semiconductor device according to the third embodiment achieves high integration of transistors, thereby realizing a semiconductor device with a reduced area. 
         [0069]    The manufacturing method of a gate electrode in the semiconductor device according to the third embodiment is described below with reference to  FIGS. 18 to 22B .  FIGS. 18 to 22B  are schematic diagrams for explaining the manufacturing method of a gate electrode in the semiconductor device according to the third embodiment, where each drawing denoted with A is a plan view, and each drawing denoted with B is a cross-sectional view along a line A-A in each corresponding drawing denoted with A. Explanations of the formation of the gate insulating film will be omitted. First, as shown in  FIG. 18 , rectangular patterns  152   p  of the gate electrodes  152  are extracted from a design layout of the semiconductor device. 
         [0070]    Next, in the extracted rectangular patterns  152   p  of the gate electrodes  152 , the rectangular pattern  152   p  of the gate electrode  152 A is used as a gate pattern A (hereinafter, “gate A”)  153  and the rectangular pattern  152   p  of the gate electrode  152 B is used as a gate pattern B (hereinafter, “gate B”)  154 . In this way, the design layout of the gate electrodes  152  is divided into two, that is, the gate A 153  and the gate B 154 . 
         [0071]    The gate electrode  152 C is divided into two substantially rectangular patterns along a borderline of position that neither overlaps (opposes) the rectangular pattern  152   p  (gate A) of the gate electrode  152 A nor the rectangular pattern  152   p  (gate B) of the gate electrode  152 B in the longitudinal direction (an X direction in  FIG. 18 ), and the two divided patterns are classified into the gate A 153  and the gate B 154  so that the patterns adjacent in the lateral direction (a Y direction in  FIG. 18 ) are differed. That is, in the two divided patterns, in the lateral direction (the Y direction in  FIG. 18 ), the rectangular pattern  152   p  of the gate electrode  152 C at a position adjacent to the rectangular pattern  152   p  (gate A) of the gate electrode  152 A is the gate B 154 , and the rectangular pattern  152   p  of the gate electrode  152 C at a position adjacent to the rectangular pattern  152   p  (gate B) of the gate electrode  152 B is the gate A 153 . 
         [0072]    In order that in each of the classified layouts, the pattern according to the design value is formed on the semiconductor substrate, there is manufactured a photomask that is formed with a gate electrode pattern corrected by using OPC. That is, two photomasks (the photomask for the gate A and the photomask for the gate B) are manufactured. At this time, the patterns for the gate A and the gate B in the photomasks are so formed that the gate A 153  and the gate B 154  are overlapped each other by several tens of nanometers in the longitudinal direction, as shown in  FIG. 19 . 
         [0073]    Next, as shown in  FIGS. 20A and 20B , on the main surface of the semiconductor substrate  151 , a polysilicon film  152   a  for forming a gate electrode is formed, and on top of it, a silicon nitride film, for example, is formed as a hard mask film  161   a.    
         [0074]    By employing photolithography using the photomask for the gate B, first resist patterns  162  is formed on the hard mask film  161   a , as shown in  FIGS. 20A and 20B . Thereby, the first resist patterns  162  is formed at a position corresponding to the gates B 154  on the main surface of the semiconductor substrate  151 . Thereafter, according to need, a process of slimming the first resist patterns  162  are performed by etching. 
         [0075]    Next, the first resist patterns  162  are used as a mask to etch the hard mask film  161   a , and as shown in  FIGS. 21A and 21B , a hard mask pattern  161  is formed on the polysilicon film  152   a . Thereby, the hard mask patterns  161  are formed at a position corresponding to the gate B 154  on the main surface of the semiconductor substrate  151 . 
         [0076]    Next, by employing photolithography using the photomask for the gate A, second resist patterns  163  are formed at a position corresponding to the gate A 153 , as shown in  FIGS. 22A and 22B . The pattern of the photomask for the gate A and the pattern of photomask for the gate B are so formed that the both patterns are overlapped each other in the longitudinal direction by several tens of nanometers, as shown in  FIG. 19 , and thus the second resist pattern  163  is so formed that one portion thereof is overlapped with the hard mask pattern  161 . Thereafter, according to need, a process of slimming the second resist patterns  163  are performed by etching. 
         [0077]    Next, the hard mask patterns  161  and the second resist patterns  163  are used as a mask to etch the polysilicon film  152   a , thereby removing the hard mask patterns  161  and the second resist patterns  163 . As a result, the gate electrode  152  can be formed as shown in  FIGS. 17A and 17B . 
         [0078]    As described above, in the manufacturing method of a gate electrode in the semiconductor device according to the third embodiment, at the time of forming the second resist patterns  163  for etching mask for forming the gate electrodes  152 A and the hard mask patterns  161  for etching mask for forming the gate electrode  152 B at a lithography step, the etching masks adjacent in the longitudinal direction are formed at different lithography steps. That is, the patterns of the gate electrodes  152  adjacent in the longitudinal direction are arranged, one pattern after the other, on the different photomasks, and transferred to the etching mask over two exposing steps. Thereby, even when the length LX 2  between the gate electrodes  152  adjacent in the longitudinal direction exceeds the resolution limit of a photolithography technique, it is possible to prevent deterioration in the dimensional accuracy which is caused due to the length LX 2  at the time of forming the etching mask and which is found in the exposure at a photolithography step, and possible to form a plurality of gate electrodes  152  with a favorable positioning accuracy at a desired position in the longitudinal direction. In the third embodiment, a case that the patterns for the gate electrodes  152  adjacent in the longitudinal direction are arranged, one pattern after the other, on the two respectively different photomasks, and transferred to the etching mask over the two exposing steps has been described. However, the patterns for the adjacent gate electrodes  152  can be separately arranged on a single photomask and transferred to the etching mask over the two exposing steps. 
         [0079]    In another manufacturing method of a gate electrode in the semiconductor device according to the third embodiment, the etching mask for forming the gate electrode  152 C is manufactured by being divided into the hard mask pattern  161  and the second resist pattern  163 . At the time of forming the hard mask pattern  161  and the second resist pattern  163 , a region in which the etching masks are overlapped in the longitudinal direction is formed at different lithography steps. Thereby, even when the length LY 2  between the gate electrodes  152  adjacent in the lateral direction exceeds the resolution limit of a photolithography technique, it is possible to prevent deterioration in the dimensional accuracy which is caused due to the length LY 2  and which is found in the exposure at a photolithography step, and possible to form a plurality of gate electrodes  152  with a favorable positioning accuracy at a desired position in the lateral direction. 
         [0080]    In the third embodiment, in the photomask for the gates A and the photomask for the gates B, the patterns for the gate A and for the gate B are formed to be overlapped each other by several tens of nanometers in the longitudinal direction, and thus the second resist pattern  163  is so formed that one portion thereof is overlapped with the hard mask pattern  161 . Thereby, at the time of forming the hard mask pattern  161  by using the photomask for the gates A, or at the time of forming the second resist pattern  163  by using the photomask for the gates B, even when slight positional deviation occurs in the longitudinal direction, the hard mask pattern  161  and the second resist pattern  163  are prevented from being separated from each other. That is, the separation of the mask pattern for forming the gate electrode  152 C, which is caused due to the formation of the photomask for forming the gate electrode  152  at two different lithography steps, can be prevented, thereby forming the gate electrode  152 C with a desired shape. 
         [0081]    Accordingly, in the method of manufacturing a gate electrode in the semiconductor device according to the third embodiment, the length between the gate electrodes adjacent in the longitudinal direction and the lateral direction is shortened, and at the same time, these members can be formed at a desired position with a favorable positioning accuracy. Thus, area reduction of a semiconductor device can be achieved. 
       Fourth Embodiment 
       [0082]    According to a fourth embodiment of the present invention, a manufacturing method of a wire layer in a semiconductor device will be described.  FIGS. 23A and 23B  are schematic diagrams for explaining arrangement of a wire layer in a semiconductor device according to the fourth embodiment, where  FIG. 23A  is a plan view thereof, and  FIG. 23B  is a cross-sectional view thereof. In  FIGS. 23A and 23B , a plurality of substantially rectangular copper (Cu) wires  172  (a Cu wire  172 A, a Cu wire  172 B, and a Cu wire  172 C) made of copper (Cu) are formed substantially parallel on an interlayer insulating film  171 . 
         [0083]    The Cu wire  172 A and the Cu wire  172 B are arranged on the substantially same line to be separated by a length LX 3  in a longitudinal direction (an X direction in  FIG. 23A . Hereinafter, “longitudinal direction”) of the Cu wire  172 . The length LX 3  is a length between the Cu wire  172 A and the Cu wire  172 B adjacent in the longitudinal direction (the X direction in  FIG. 23A ). The Cu wire  172 C is so positioned that it is separated by a length LY 3  in a lateral direction (a Y direction in  FIG. 23A . Hereinafter, “lateral direction”) of the Cu wire  172  relative to the Cu wire  172 A and the Cu wire  172 B and that it is overlapped by the substantially same length only with respect to the Cu wire  172 A and Cu wire  172 B in the longitudinal direction (the X direction in  FIG. 23A ). The length LX 3  is a length between the Cu wire  172 A and the Cu wire  172 C, and between the Cu wire  172 B and the Cu wire  172 C, adjacent in the lateral direction (the Y direction in  FIG. 23A ). 
         [0084]    In the fourth embodiment, the length LX 3  is set to a very short length that exceeds the resolution limit of a photolithography technique, making it very difficult to form its configuration. Moreover, the length LY 3  is set to a very short length that exceeds the resolution limit of a photolithography technique, making it very difficult to form its configuration. By having such a layout, the semiconductor device according to the fourth embodiment enables high integration of transistors and area reduction. 
         [0085]    A manufacturing method of the Cu wire  172  in a semiconductor device according to the fourth embodiment is described next. First, from the design layout of the semiconductor device, rectangular patterns for the Cu wires  172  are extracted. Subsequently, in the extracted rectangular pattern for the Cu wire  172 , a rectangular pattern for the Cu wire  172 A is a wire pattern A (Hereinafter, “wire A”)  173  and a rectangular pattern for the Cu wire  172 B is a wire pattern B (Hereinafter, “wire B”)  174 , as shown in  FIG. 24 . In this way, the design layout of the Cu wire  172  is classified into two, that is, the wire A  173  and the wire B  174 . 
         [0086]    Thereafter, when the same steps as those after  FIG. 20  in the third embodiment are implemented, the (Cu) wires  172  (the Cu wire  172 A, the Cu wire  172 B, and the Cu wire  172 C) can be formed. In this case, the wire A corresponds to the gate A and the wire B corresponds to the gate B. In the fourth embodiment, instead of the polysilicon film  152   a , a Cu film is formed. 
         [0087]    In the manufacturing method of a wire layer in the semiconductor device according to the fourth embodiment, at the time of forming the etching mask for forming the Cu wire  172 A at a lithography step, the etching masks adjacent in the longitudinal direction are formed at different lithography steps. That is, the patterns for the Cu wires  172  adjacent in the longitudinal direction are arranged, one pattern after the other, on the different photomasks, and transferred to the etching mask over two exposing steps. Thereby, even when the length LX 3  between the Cu wires  172  adjacent in the longitudinal direction exceeds the resolution limit of a photolithography technique, it is possible to prevent deterioration in the dimensional accuracy which is caused due to the length LY 3  at the time of forming the etching mask and which is found in the exposure at a photolithography step, and possible to form a plurality of Cu wires  172  with a favorable positioning accuracy at a desired position in the longitudinal direction. In the fourth embodiment, a case that the patterns for the Cu wires  172  adjacent in the longitudinal direction are arranged, one pattern after the other, on the respectively different photomasks, and transferred to the etching mask over the two exposing steps has been described. However, the patterns for the adjacent Cu wires  172  can be separately arranged on a single photomask and transferred to the etching mask over the two exposing steps. 
         [0088]    In another semiconductor device manufacturing method according to the fourth embodiment, the etching mask for forming the Cu wire  172 C is manufactured in a divided manner. At the time of forming the etching mask, a region in which the etching masks are overlapped in the longitudinal direction is formed at different lithography steps. Thereby, even when the length LY 3  between the Cu wires  172  adjacent in the lateral direction exceeds the resolution limit of a photolithography technique, it is possible to prevent deterioration in the dimensional accuracy which is caused due to the length LY 3  and which is found in the exposure at a photolithography step, and possible to form a plurality of Cu wires  172  with a favorable positioning accuracy at a desired position in the lateral direction. 
         [0089]    In the fourth embodiment, in the photomask for the wires A and the photomask for the wires B, the patterns for the wires A and for the wire B are formed to be overlapped each other by several tens of nanometers in the longitudinal direction. Thereby, the separation of the mask pattern for forming the Cu wire  172 , which is caused due to the formation of the photomask for forming the Cu wires  172  at two different lithography steps, can be prevented, thereby forming Cu wire  172 C with a desired shape. 
         [0090]    Accordingly, in the method of manufacturing a wire layer in the semiconductor device according to the fourth embodiment, the length between wires adjacent in the longitudinal direction and the lateral direction is shortened, and at the same time, these members can be formed at a desired position with a favorable positioning accuracy. Thus, area reduction of a semiconductor device can be achieved. 
         [0091]    Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Technology Classification (CPC): 7