Patent Publication Number: US-10763017-B2

Title: Metal plate resistor and method for manufacturing same

Description:
FIELD OF THE INVENTION 
     The present disclosure relates to a metal plate resistor that is used to detect a current amount by measuring a voltage between a pair of electrodes in information communication equipment represented by smartphones or tablets. 
     DESCRIPTION OF THE RELATED ART 
     A conventional metal plate resistor includes resistor body  1  that includes a metal plate including CuNi, a pair of electrodes  2   a,    2   b  that are formed on a lower surface of resistor body  1  and include Cu, plating layers  3  that are used to improve soldering, first protection film  4  that is formed between the pair of electrodes  2   a,    2   b  on the lower surface of resistor body  1 , and second protection film  5  that is formed on an upper surface of resistor body  1 , as illustrated in  FIG. 16 . 
     As citation list information relating to the invention of the present application, PTL 1 is known, for example. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Unexamined Japanese Patent Publication No. 2004-311747 
     SUMMARY OF THE INVENTION 
     In the conventional configuration described above, a current only flows through the pair of electrodes  2   a,    2   b  and a portion near a lower surface between the pair of electrodes  2   a,    2   b  of resistor body  1 , and therefore a resistance value fails to be reduced. Further, a ratio increases at which a thermal coefficient of resistance (TCR) of the pair of electrodes  2   a,    2   b  that include Cu having a large TCR of 4300×10 6 /° C. contributes to a TCR of an entirety of the metal plate resistor. Thus, there is a problem in which the TCR increases as the resistance value is reduced. 
     The present disclosure has been made to solve the conventional problem described above, and it is an object of the present disclosure to provide a metal plate resistor that is capable of reducing a resistance value and a TCR. 
     In order to solve the problem described above, the invention of the present disclosure includes a pair of electrodes that include a metal having a low electrical resistivity and a high TCR in comparison with a resistor body, and an internal electrode that is formed on an upper surface of the resistor body. The internal electrode includes a metal having a low electrical resistivity in comparison with the resistor body. 
     In a metal plate resistor according to the present disclosure, due to the internal electrode, a resistance value of a path to an upper side (a side of the internal electrode) is reduced. Therefore, a larger current flows to the upper side. This enables the resistance value to be reduced. In addition, in the metal plate resistor according to the present disclosure, when temperature increases, a resistance value of the pair of electrodes increases. Therefore, a current that flows to the upper side of the resistor body further increases. This causes a measured resistance value to be reduced, and therefore an effect of a reduction in a TCR is exhibited. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a sectional view of a metal plate resistor according to an exemplary embodiment of the present disclosure. 
         FIG. 2  is a sectional view illustrating a state where the same metal plate resistor has been mounted. 
         FIG. 3A  is a top view of a prepared sheet resistor body in a first manufacturing method. 
         FIG. 3B  is a sectional view taken along line III B-III B of the sheet resistor body of  FIG. 3A . 
         FIG. 3C  is a top view of a sheet resistor body in which a protection member has been formed in the first manufacturing method. 
         FIG. 3D  is a sectional view taken along line III D-III D of the sheet resistor body of  FIG. 3C . 
         FIG. 4A  is a top view of a sheet resistor body in which holes have been formed in predetermined portions of the protection member by using a laser in the first manufacturing method. 
         FIG. 4B  is a sectional view taken along line IV B-IV B of the sheet resistor body of  FIG. 4A . 
         FIG. 4C  is a top view of a sheet resistor body at a time when electrode parts have been formed in predetermined portions of an upper surface of the sheet resistor body and internal electrode parts have been formed inside the holes on a lower surface of the sheet resistor body in the first manufacturing method. 
         FIG. 4D  is a sectional view taken along line IV D-IV D of the sheet resistor body of  FIG. 4C . 
         FIG. 5A  is a sectional view of a sheet resistor body at a time when a resin substrate has been stuck by pressing on lower surfaces of the protection member and the internal electrode parts in the first manufacturing method. 
         FIG. 5B  is a top view of a sheet resistor body in a case where a protection film has been formed among a plurality of electrode parts in the first manufacturing method. 
         FIG. 5C  is a sectional view taken along line V C-V C of the sheet resistor body of  FIG. 5B . 
         FIG. 5D  is a sectional view of a metal plate resistor in the form of an individual piece. 
         FIG. 6  is a diagram illustrating a relationship between a thickness of a resistor body with respect to an interval between a pair of electrodes and a TCR in a metal plate resistor according to the present disclosure. 
         FIG. 7  is a diagram illustrating a relationship between a difference between an interval between a pair of electrodes and a length of an internal electrode and a TCR in the same metal plate resistor. 
         FIG. 8  is a sectional view illustrating a variation of a metal plate resistor according to the present disclosure. 
         FIG. 9A  is a top view of a sheet resistor body obtained by configuring metal in a plate shape in a second manufacturing method. 
         FIG. 9B  is a sectional view taken along line IX B-IX B of the sheet resistor body of  FIG. 9A . 
         FIG. 10A  is a top view of a sheet resistor body with a resin substrate stuck in the second manufacturing method. 
         FIG. 10B  is a sectional view taken along line X B-X B of the sheet resistor body of  FIG. 10A . 
         FIG. 10C  is a bottom view of a sheet resistor body in which a plurality of electrode parts have been formed in a belt shape in the second manufacturing method. 
         FIG. 10D  is a sectional view taken along line X D-X D of the sheet resistor body of  FIG. 10C . 
         FIG. 11A  is a bottom view of a sheet resistor body at a time when a plurality of grooves have been formed in a belt shape in the second manufacturing method. 
         FIG. 11B  is a sectional view taken along line XI B-XI B of the sheet resistor body of  FIG. 11A . 
         FIG. 11C  is a bottom view of a sheet resistor body at a time when a protection film has been formed in the second manufacturing method. 
         FIG. 11D  is a sectional view taken along line XI D-XI D of the sheet resistor body of  FIG. 11C . 
         FIG. 12A  is a bottom view of sheet resistor body immediately after cutting in center parts of the grooves in the second manufacturing method. 
         FIG. 12B  is a sectional view taken along line XII B-XII B of the sheet resistor body of  FIG. 12A . 
         FIG. 13A  is a top view of a sheet resistor body at a time when a plurality of internal electrode parts have been formed on an upper surface of the sheet resistor body so as to be disposed at fixed intervals in a horizontal direction and a vertical direction and a plurality of electrode parts have been formed on a lower surface of the sheet resistor body so as to be disposed at fixed intervals in the horizontal direction and the vertical direction in a third manufacturing method. 
         FIG. 13B  is a sectional view taken along line XIII B-XIII B of the sheet resistor body of  FIG. 13A . 
         FIG. 13C  is a sectional view taken along line XIII C-XIII C of the sheet resistor body of  FIG. 13A . 
         FIG. 14A  is a top view of a sheet resistor body at a time when a first protection member has been formed in the third manufacturing method. 
         FIG. 14B  is a sectional view taken along line XIV B-XIV B of the sheet resistor body of  FIG. 14A . 
         FIG. 14C  is a bottom view of sheet resistor body viewed from a side of a plurality of electrode parts at a time when the plurality of electrode parts and a plurality of grooves have been formed in the third manufacturing method. 
         FIG. 14D  is a sectional view taken along line XIV D-XIV D of the sheet resistor body of  FIG. 14C . 
         FIG. 15A  is a bottom view of a sheet resistor body at a time when a second protection member has been formed in the third manufacturing method. 
         FIG. 15B  is a sectional view taken along line XV B-XV B of the sheet resistor body of  FIG. 15A . 
         FIG. 15C  is a bottom view of a sheet resistor body immediately after division into a plurality of individual pieces in the third manufacturing method. 
         FIG. 15D  is a sectional view taken along line XV D-XV D of the sheet resistor body of  FIG. 15C . 
         FIG. 16  is a sectional view of a conventional metal plate resistor. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a sectional view of a metal plate resistor according to one exemplary embodiment of the present disclosure. 
     A metal plate resistor according to one exemplary embodiment includes resistor body  11 , a pair of electrodes (electrode  12   a  and electrode  12   b ), first protection film  13 , internal electrode  14 , and plating layers  15 , as illustrated in  FIG. 1 . Resistor body  11  includes a metal plate that has an upper surface and a lower surface that are spaced apart from each other in a thickness direction. The pair of electrodes  12   a,    12   b  are formed on both sides of the lower surface of resistor body  11 . First protection film  13  covers resistor body  11  between the pair of electrodes  12   a,    12   b.  Internal electrode  14  is formed on the upper surface of resistor body  11 . Plating layers  15  are formed on end surfaces of resistor body  11  and lower surfaces of the pair of electrodes  12   a,    12   b.  Here, the end surfaces refer to surfaces with a vector along an X-axis direction as a normal line in resistor body  11  illustrated in  FIG. 1 . 
     In addition, the pair of electrodes  12   a,    12   b  include a metal that has a low electrical resistivity (a low specific electrical resistance) and a high TCR in comparison with resistor body  11 . Internal electrode  14  includes a metal that has a low electrical resistivity in comparison with resistor body  11 . 
     In a configuration of the metal plate resistor described above, resistor body  11  includes a metal that has a relatively high electrical resistivity and a relatively low TCR, for example, a metal including nichrome, copper nickel, manganin, or the like. 
     Resistor body  11  described above includes a metal plate that has an upper surface and a lower surface that are spaced apart from each other in a thickness direction. In a case where a resistance value is adjusted, a slit that does not pierce resistor body  11  is formed on a side of the lower surface of resistor body  11 . A large current flows on a side of a lower surface between the pair of electrodes  12   a,    12   b  of resistor body  11 . Therefore, a rate of an increase in a resistance value due to formation of the slit can be increased. Thus, the resistance value can be finely adjusted. 
     In addition, the pair of electrodes  12   a,    12   b  are provided in both ends of the lower surface of resistor body  11 , and include a metal, such as coper or silver, that has a low electrical resistivity (a low specific electrical resistance) and a high TCR in comparison with resistor body  11 . The pair of electrodes  12   a,    12   b  described above include a thick-film material or plating. 
     Further, first protection film  13  is provided between the pair of electrodes  12   a,    12   b  so as to cover resistor body  11 , and includes a thick-film material including epoxy resin or the like. 
     Furthermore, internal electrode  14  includes a metal, such as copper or silver, that has a low electrical resistivity in comparison with resistor body  11 . It is preferable that a metal included in internal electrode  14  be identical to a metal included in the pair of electrodes  12   a,    12   b.    
     In addition, internal electrode  14  described above is provided in a middle part of a longitudinal direction (a direction in which the pair of electrodes  12   a,    12   b  face each other (an X-direction)) on the upper surface of resistor body  11 . Internal electrode  14  is formed according to a method such as printing, plating, or embedding using a clad. Further, a center part between the pair of electrodes  12   a,    12   b  that face each other in the longitudinal direction (the X-direction) overlaps a center part of internal electrode  14  in a top view. 
     Furthermore, a length in the longitudinal direction of internal electrode  14  has been set to be shorter than an interval in the longitudinal direction between the pair of electrodes  12   a,    12   b  in a top view in such a way that the pair of electrodes  12   a,    12   b  do not overlap internal electrode  14  in the top view. In addition, an upper surface of internal electrode  14  and an upper surface of resistor body  11  that is exposed from internal electrode  14  are coated with second protection film  16  including epoxy resin. Second protection film  16  may include epoxy resin and a resin substrate. 
     Plating layers  15  are integrally formed on the end surfaces of resistor body  11  and the lower surfaces of the pair of electrodes  12   a,    12   b.  Plating layers  15  described above include nickel plating and tin plating, and are provided in order to improve soldering. 
     Resistor body  11  may include alloy or a metal multilayer film. 
     Here,  FIG. 2  illustrates a state where a metal plate resistor according to one exemplary embodiment of the present disclosure is mounted in mounting substrate  21 . 
     Plating layers  15  are connected to lands  22  of mounting substrate  21  via mounting solders  23 . In addition, lands  22  are located under the lower surfaces of the pair of electrodes  12   a,    12   b.  A current flows from lands  22  via mounting solders  23 , plating layers  15  and the pair of electrodes  12   a,    12   b  to resistor body  11 . A voltage is measured in portions  22   a  that face each other in the longitudinal direction (the X-direction) of lands  22 . A current value is detected by using a measured voltage value and the resistance value. 
     A method for manufacturing a metal plate resistor according to one exemplary embodiment of the present disclosure is described below with reference to the drawings. 
     In order to improve productivity, a description is provided in a state where the metal plate resistor in the description above of  FIGS. 1 and 2  has been turned upside-down. 
     (First Manufacturing Method) 
     A method for manufacturing a metal plate resistor according to the present disclosure (a first manufacturing method) is described with reference to  FIGS. 3A to 5D . 
     First, as illustrated in  FIGS. 3A and 3B , sheet resistor body  25  is prepared that has been obtained by configuring a metal including CuMnNi alloy or the like in a plate shape. A plurality of cutouts  26  having a belt shape are provided in sheet resistor body  25  described above so as to be parallel to each other. Cutouts  26  are formed by etching. 
     Sheet resistor body  25  has one surface and another surface that are spaced apart from each other in the thickness direction. The one surface and the other surface face each other. 
     Here,  FIG. 3A  is a top view of sheet resistor body  25  that has been prepared.  FIG. 3B  is a sectional view taken along line III B-III B of sheet resistor body  25  of  FIG. 3A . 
     Next, as illustrated in  FIGS. 3C and 3D , protection member  27  is simultaneously formed on one surface (a lower surface) of sheet resistor body  25  and inside cutouts  26 . Protection member  27  is a film including epoxy resin, and a member that increases fluidity by vacuum hot pressing is used. Protection member  27  is formed on the lower surface of sheet resistor body  25 , and an inside of each of cutouts  26  is also filled with protection member  27 . Then, protection member  27  is hardened. 
     In protection member  27  described above, a portion on the lower surface of sheet resistor body  25  serves as second protection film  16  of a metal plate resistor in the form of an individual piece, and a third protection member (hereinafter not illustrated) on side surfaces of the metal plate resistor. Second protection film  16  and the third protection film are integrally formed. 
     Here,  FIG. 3C  is a top view of sheet resistor body  25  in which protection member  27  has been formed.  FIG. 3D  is a sectional view taken along line III D-III D of  FIG. 3C . 
     Next, as illustrated in  FIGS. 4A and 4B , holes  28  are formed by using a laser in predetermined portions of protection member  27  that has been formed on the lower surface of sheet resistor body  25 . Holes  28  are formed in portions where cutouts  26  have not been formed, namely, in portions between cutout  26  and cutout  26 . 
     Here,  FIG. 4A  is a top view of sheet resistor body  25  in which holes  28  have been formed by using a laser in predetermined portions of protection member  27 .  FIG. 4B  is a sectional view taken along line IV B-IV B of sheet resistor body  25  of  FIG. 4A . 
     Next, as illustrated in  FIGS. 4C and 4D , electrode parts  29  are formed in predetermined portions on another surface (an upper surface) of sheet resistor body  25 , and internal electrode parts  30  are formed inside holes  28  on the lower surface of sheet resistor body  25 . 
     At this time, another resist is stuck on the upper surface of sheet resistor body  25 , and the upper surface of sheet resistor body  25  is plated. At this time, the other resist described above is patterned with island shapes in portions between cutouts  26  (filled with protection member  27 ) of sheet resistor body  25 . Then, Cu plating is performed, and the other resist is removed. As a result, a plurality of electrode parts  29  including Cu plating are formed at equal intervals in portions between adjacent cutouts  26 . 
     In addition, simultaneously, a plurality of internal electrode parts  30  including Cu plating are also formed inside holes  28  on the lower surface of sheet resistor body  25 . In a metal plate resistor in the form of an individual piece, electrode parts  29  serve as a pair of electrodes  12   a,    12   b,  and internal electrode part  30  serves as internal electrode  14 . 
     Before the plurality of electrode parts  29  are formed by Cu plating, an inside of each of cutouts  26  is filled with protection member  27 , and therefore plating solution does not enter the inside of each of cutouts  26 . By doing this, even when a width of each of the plurality of electrode parts  29  increases, excess plating is not formed in the plurality of electrode parts  29 . 
     Here,  FIG. 4C  is a top view of sheet resistor body  25  at a time when electrode parts  29  have been formed in predetermined portions on the upper surface of sheet resistor body  25  and internal electrode parts  30  have been formed inside holes  28  on the lower surface of sheet resistor body  25 .  FIG. 4D  is a sectional view taken along line IV D-IV D of sheet resistor body  25  of  FIG. 4C . 
     Next, as illustrated in  FIG. 5A , under the lower surface of sheet resistor body  25 , resin substrate  31  is stuck by pressing on lower surfaces of protection member  27  and internal electrode parts  30 . Resin substrate  31  is a substrate that includes epoxy resin and glass and that has a high strength, and resin substrate  31  includes the same material as a material of mounting substrate  21 . Resin substrate  31  allows easy handing in processes that follow. 
     Thereafter, a slit may be formed as needed, and a resistance value may be adjusted. 
     Next, as illustrated in  FIGS. 5B and 5C , protection film  32  is formed among the plurality of electrode parts  29 . Protection film  32  described above includes epoxy resin, and is formed so as to cover a space among the plurality of electrode parts  29  and upper surfaces of the plurality of electrode parts  29 . After protection film  32  is hardened, protection film  32  is polished until the plurality of electrode parts  29  are exposed. In a metal pate resistor in the form of an individual piece, protection film  32  serves as first protection film  13 . 
     Here,  FIG. 5A  is a sectional view of a sheet resistor body at a time when resin substrate  31  has been stuck by pressing on the lower surfaces of protection member  27  and internal electrode parts  30 .  FIG. 5B  is a top view of sheet resistor body  25  in a case where protection film  32  has been formed among the plurality of electrode parts  29 .  FIG. 5C  is a sectional view taken along line V C-V C of sheet resistor body  25  of  FIG. 5B . 
     Next, middle parts of cutouts  26  and middle parts of the plurality of electrode parts  29  are cut, and division is performed so as to form individual pieces. 
     Finally, Ni plating and Sn plating is performed from upper surfaces of a pair of electrodes  12   a,    12   b  (electrode parts  29 ) to end surfaces of resistor body  11  of each of metal plate resistors obtained by division into individual pieces, plating layers  15  are formed, and a metal plate resistor in the form of an individual piece, as illustrated in  FIG. 5D , is obtained. 
     For a simple description,  FIGS. 3A to 5D  illustrate a portion where  12  cutouts  26 , and metal plate resistors in the form of an individual piece in 5 columns and 4 rows have been formed in a sheet shape. 
     Resin substrate  31  is formed on upper surfaces of second protection film  16  (protection member  27 ) and internal electrode  14  (internal electrode part  30 ), as illustrated in  FIG. 5D . By doing this, resistor body  11  can be suppressed from being deformed due to heat generation or the like of resistor body  11 . 
     As described above, in a metal plate resistor according to one exemplary embodiment of the present disclosure, internal electrode  14  is formed on an upper surface of resistor body  11 , and internal electrode  14  includes a metal, the electrical resistivity of the metal is lower than the electrical resistivity of resistor body  11 . Therefore, a resistance value on a path to an upper side (a side of internal electrode  14 ) is reduced. This causes a larger current to flow to the upper side (the side of internal electrode  14 ) in resistor body  11 . Thus, an effect of a reduction in the resistance value can be exhibited. 
     Further, when temperature increases, a resistance value of the pair of electrodes  12   a,    12   b  increases, and therefore a current that flows to the upper side of resistor body  11  further increases. By doing this, a measured resistance value is reduced, and this enables a TCR to be reduced. 
     (Characteristics of Metal Plate Resistor) 
     Characteristics of a metal plate resistor according to the present disclosure are described below. 
       FIG. 6  is a diagram illustrating a relationship between a thickness of resistor body  11  with respect to a length in a longitudinal direction of an interval between a pair of electrodes  12   a,    12   b  and a TCR. 
     As is evident from  FIG. 6 , when the thickness of resistor body  11  becomes 0.4 times or more the length of the interval between the pair of electrodes  12   a,    12   b,  the TCR becomes less than 100 ppm/° C. This is because, when the thickness of resistor body  11  increases, a current that flows along the thickness direction further increases, and the resistance value further decreases. Note that an upper limit value is specified in consideration of a request from a user, productivity, or the like, but the upper limit value is generally 100 ppm/° C. in metal plate resistors. 
     Accordingly, it is preferable that the thickness of resistor body  11  be set to be 0.4 times or more the length in the longitudinal direction of the interval between the pair of electrodes  12   a,    12   b.    
       FIG. 7  is a diagram illustrating a relationship between a difference between a length of an interval between a pair of electrodes  12   a,    12   b  and a length of internal electrode  14  in the longitudinal direction and a TCR. 
     As is evident from  FIG. 7 , in a case where the length of internal electrode  14  becomes a length that is less than or equal to the interval between the pair of electrodes  12   a,    12   b,  namely, in a case where internal electrode  14  does not overlap the pair of electrodes  12   a,    12   b  in a top view, the TCR becomes less than 100 ppm/° C. 
     As a reason for this, when a distance between the pair of electrodes  12   a ,  12   b  and internal electrode  14  increases in a top view, a current that flows from the pair of electrodes  12   a,    12   b  to internal electrode  14  increases. Therefore, a current that flows along the thickness direction further increases, and the resistance value further decreases, as described above. Note that a lower limit value is determined according to a specified resistance value. 
     (Variation of Metal Plate Resistor) 
     As a variation of the metal plate resistor, the pair of electrodes  12   a ,  12   b  may be integrally formed from the lower surface of resistor body  11  to the end surfaces, as illustrated in  FIG. 8 . This enables a larger current to flow to an upper side (a side of internal electrode  14 ) in resistor body  11 . Thus, the resistance value can be easily reduced. 
     (Second Manufacturing Method) 
     A method for manufacturing a metal plate resistor according to one exemplary embodiment may be formed according to the method described below. A method for manufacturing a metal plate resistor according to the present disclosure (a second manufacturing method) is described with reference to  FIGS. 9A to 12B . 
     First, as illustrated in  FIGS. 9A and 9B , sheet resistor body  25  is prepared. Sheet resistor body  25  has one surface and another surface that are spaced apart from each other in the thickness direction, and is obtained by configuring a metal including CuMnNi alloy or the like in a plate shape. On the one surface (an upper surface) of sheet resistor body  25 , a plurality of internal electrode parts  30  are formed in a belt shape so as to be located at fixed intervals. 
     The plurality of internal electrode parts  30  are formed by being plated with Cu, and are also formed in a belt shape by using a photolithographic method. 
     Here,  FIG. 9A  is a top view of sheet resistor body  25  obtained by configuring metal in a plate shape.  FIG. 9B  is a sectional view taken along line IX B-IX B of sheet resistor body  25  of  FIG. 9A . 
     Next, as illustrated in  FIGS. 10A and 10B , resin substrate  31  is stuck so as to cover an upper surface of sheet resistor body  25  and the plurality of internal electrode parts  30 . The plurality of internal electrode parts  30  are not exposed to an outside due to resin substrate  31 . Resin substrate  31  is a substrate that includes epoxy resin and glass and that has a high strength, and resin substrate  31  includes the same material as a material of mounting substrate  21 . 
     Here,  FIG. 10A  is a top view of sheet resistor body  25  with resin substrate  31  stuck.  FIG. 10B  is a sectional view taken along line X B-X B of sheet resistor body  25  of  FIG. 10A . 
     Next, as illustrated in  FIGS. 10C and 10D , a plurality of electrode parts  29  are formed in a belt shape on another surface of sheet resistor body  25  (a lower surface, namely, a surface on a side reverse to a surface on which resin substrate  31  has been stuck of sheet resistor body  25 ) so as to be located at fixed intervals. The plurality of electrode parts  29  described above are provided almost in parallel to the plurality of internal electrode parts  30 , but the plurality of electrode parts  29  do not overlap the plurality of internal electrode parts  30  in a plan view. In addition, electrode part  29  is located in a middle part between adjacent internal electrode parts  30 . Here, the plan view refers to a view from the upper surface of sheet resistor body  25 . 
     Here,  FIG. 10C  is a bottom view (a view from a side of the electrode parts  29 ) of sheet resistor body  25  in which the plurality of electrode parts  29  have been formed in a belt shape.  FIG. 10D  is a sectional view taken along line X D-X D of sheet resistor body  25  of  FIG. 10C . 
     In a metal plate resistor in the form of an individual piece, electrode parts  29  serve as a pair of electrodes  12   a,    12   b,  internal electrode part  30  serves as internal electrode  14 , and resin substrate  31  serves as second protection film  16 . 
     Next, as illustrated in  FIGS. 11A and 11B , a plurality of grooves  33  are formed in a belt shape on the lower surface of sheet resistor body  25  so as to be orthogonal to the plurality of internal electrode parts  30  and the plurality of electrode parts  29  in the plan view. 
     The plurality of grooves  33  completely pierce center parts of sheet resistor body  25  and the plurality of electrode parts  29 , but the plurality of grooves  33  are only formed up to a midway part of resin substrate  31  (the plurality of grooves  33  do not completely pierce resin substrate  31 ). The plurality of grooves  33  are formed by dicing. By doing this, dimensional precision in a direction of a side surface of the metal plate resistor can be improved. 
     Here,  FIG. 11A  is a bottom view of sheet resistor body  25  at a time when the plurality of grooves  33  have been formed in a belt shape.  FIG. 11B  is a sectional view taken along line XI B-XI B of sheet resistor body  25  of FIG.  11 A. 
     Thereafter, a slit may be formed as needed, and a resistance value may be adjusted. 
     Next, as illustrated in  FIGS. 11C and 11D , protection film  34  is formed so as to completely cover the lower surface of sheet resistor body  25  and the plurality of electrode parts  29 . In addition, protection film  34  includes epoxy resin, and an inside of each of the plurality of grooves  33  is also filled with protection film  34 . Then, protection film  34  is hardened, and protection film  34  is polished until the plurality of electrode parts  29  are exposed. 
     Protection film  34  serves as first protection film  13  of a metal plate resistor in the form of an individual piece and a third protection film on side surfaces of the metal plate resistor. First protection film  13  and the third protection film are integrally formed. 
     Here,  FIG. 11C  is a bottom view of sheet resistor body  25  at a time when protection film  34  has been formed.  FIG. 11D  is a sectional view taken along line XI D-XI D of sheet resistor body  25  of  FIG. 11C . 
     Next, as illustrated in  FIGS. 12A and 12B , sheet resistor body  25  is cut in middle parts  35   a  of the plurality of electrode parts  29  and center parts  35   b  of grooves  33  so as to be divided into individual pieces. 
     Here,  FIG. 12A  is a bottom view of sheet resistor body  25  immediately after cutting in middle parts  35   a  of the plurality of electrode parts  29  and center parts  35   b  of grooves  33 .  FIG. 12B  is a sectional view taken along line XII B-XII B of sheet resistor body  25  of  FIG. 12A . 
     Finally, Ni plating and Sn plating is performed from upper surfaces of a pair of electrodes  12   a,    12   b  (electrode parts  29 ) to end surfaces of resistor body  11  in each of the metal plate resistors obtained by performing division into individual pieces, and plating layers  15  are formed. 
     (Third Manufacturing Method) 
     In addition, a method for manufacturing a metal plate resistor according to one exemplary embodiment may be formed according to the method described below. A method for manufacturing a metal plate resistor according to the present disclosure (a third manufacturing method) is described with reference to  FIGS. 13A to 15D . 
     First, as illustrated in  FIGS. 13A, 13B, and 13C , sheet resistor body  25  is prepared. Sheet resistor body  25  has one surface and another surface that are spaced apart from each other in the thickness direction, and is obtained by configuring a metal including CuMnNi alloy or the like in a plate shape. On the one surface (an upper surface) of sheet resistor body  25 , a plurality of internal electrode parts  30  are formed that are disposed at fixed intervals in a horizontal direction and a vertical direction. On the other surface (a lower surface) of sheet resistor body  25 , a plurality of electrode parts  29  are formed that are disposed at fixed intervals in the horizontal direction and the vertical direction. 
     At this time, the plurality of internal electrode parts  30  and the plurality of electrode parts  29  are configured so as not to overlap each other in a plan view and to be disposed in one line when viewed from the horizontal direction, as illustrated in  FIG. 13C . 
     The plurality of internal electrode parts  30  and the plurality of electrode parts  29  are formed by being plated with Cu, and are also formed in an island shape by using a photolithographic method. 
     In a metal plate resistor in the form of an individual piece, electrode parts  29  serve as a pair of electrodes  12   a,    12   b,  and internal electrode part  30  serves as internal electrode  14 . 
     Here,  FIG. 13A  is a top view of sheet resistor body  25  at a time when the plurality of internal electrode parts  30  have been formed on the one surface (the upper surface) of sheet resistor body  25  so as to be disposed at fixed intervals in the horizontal direction and the vertical direction and the plurality of electrode parts  29  have been formed on the other surface (the lower surface) of sheet resistor body  25  so as to be disposed at fixed intervals in the horizontal direction and the vertical direction. In addition,  FIG. 13B  is a sectional view taken along line XIII B-XIII B of sheet resistor body  25  of  FIG. 13A .  FIG. 13C  is a sectional view taken along line XIII C-XIII C of sheet resistor body  25  of  FIG. 13A . 
     Next, as illustrated in  FIGS. 14A and 14B , first protection member (protection film)  27   a  is formed so as to cover the upper surface of sheet resistor body  25  and the plurality of internal electrode parts  30 . Then, first protection member  27   a  is hardened. Further, resin substrate (protection film)  31  is stuck so as to cover first protection member  27   a.    
     First protection member  27   a  is a film including epoxy resin, and a member that increases fluidity by vacuum hot pressing is used. First protection member  27   a  serves as second protection film  16  in a metal plate resistor in the form of an individual piece. Resin substrate  31  is a substrate that includes epoxy resin and glass and that has a high strength, and resin substrate  31  includes the same material as a material of mounting substrate  21 . 
     Here,  FIG. 14A  is a top view of sheet resistor body  25  at a time when first protection member  27   a  has been formed.  FIG. 14B  is a sectional view taken along line XIV B-XIV B of sheet resistor body  25  of  FIG. 14A . 
     Next, as illustrated in  FIGS. 14C and 14D , groove  36  is formed in each space between a plurality of electrode parts  29  that are disposed in one line when viewed from the horizontal direction and an adjacent plurality of electrode parts  29  that are disposed in one line. 
     Grooves  36  completely pierce sheet resistor body  25  and first protection member  27   a,  but grooves  36  are only formed up to a midway part of resin substrate  31  (grooves  36  do not completely pierce resin substrate  31 ). Grooves  36  are formed by dicing. By doing this, dimensional precision in a direction of a side surface of the metal plate resistor can be improved. 
     Here,  FIG. 14C  is a bottom view of sheet resistor body  25  viewed from a side of the plurality of electrode parts  29  at a time when the plurality of electrode parts  29  and grooves  36  have been formed.  FIG. 14D  is a sectional view taken along line XIV D-XIV D of sheet resistor body  25  of  FIG. 14C . 
     Thereafter, a slit may be formed as needed, and a resistance value may be adjusted. 
     Next, as illustrated in  FIGS. 15A and 15B , second protection member (another protection film)  27   b  is formed so as to cover the lower surface of sheet resistor body  25  and the plurality of electrode parts  29 . 
     In addition, second protection member  27   b  is a film including epoxy resin, and a member that increases fluidity by vacuum hot pressing is used. An inside of each of grooves  36  is also filled with second protection member  27   b.  Then, second protection member  27   b  is hardened, and second protection member  27   b  is polished until the plurality of electrode parts  29  are exposed. 
     Second protection member  27   b  serves as first protection film  13  of a metal plate resistor in the form of an individual piece and a third protection film on side surfaces of the metal plate resistor. First protection film  13  and the third protection film are integrally formed. 
     Here,  FIG. 15A  is a bottom view of sheet resistor body  25  at a time when second protection member (the other protection film)  27   b  has been formed.  FIG. 15B  is a sectional view taken along line XV B-XV B of  FIG. 15A . 
     Next, as illustrated in  FIGS. 15C and 15D , sheet resistor body  25  is cut in middle parts  37   a  of the plurality of electrode parts  29  and center parts  37   b  of grooves  36  so as to be divided into a plurality of individual pieces. 
     Here,  FIG. 15C  is a bottom view of sheet resistor body  25  immediately after division into a plurality of individual pieces.  FIG. 15D  is a sectional view taken along line XV D-XV D of sheet resistor body  25  of  FIG. 15C . 
     Finally, Ni plating and Sn plating is performed from upper surfaces of a pair of electrodes  12   a,    12   b  (electrode parts  29 ) to end surfaces of resistor body  11  in each of the metal plate resistors obtained by performing division into individual pieces, and plating layers  15  are formed. 
     A metal plate resistor according to the present disclosure exhibits an effect of being capable of reducing a resistance value and a TCR, and is useful as a metal plate resistor or the like that is used for the purpose of detection of a current of information communication equipment represented by smartphones or tablets.