Abstract:
This wiring board is provided with an insulating core substrate, a first conductor pattern, a second conductor pattern, and a conductive material. The first conductor pattern and the second conductor pattern are adhered to the insulating core substrate. The second conductor pattern has a first surface and a second surface. The second conductor pattern has a concavity and a through-hole. The opening of the concavity that opens to the first surface and the opening of the through hole that opens to the first surface are interconnected to each other. The first conductor pattern is positioned at the opening of the concavity. The first conductor pattern and the second conductor pattern are electrically connected by means of the conductive material, which fills from the opening of the through hole that opens to the second surface.

Description:
TECHNICAL FIELD 
     The present invention relates to a wiring board. 
     BACKGROUND ART 
     As a technique related to a wiring board, a known technique stacks wires on a support body (for example, patent publication 1). 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         Patent Document 1: Japanese Laid-Out Patent Publication No. 2000-91716 
       
    
     SUMMARY OF THE INVENTION 
     When patterned copper plates are adhered to an insulative core substrate to form a substrate, if a thin copper plate and a thick copper plate are stacked together on an insulative core substrate, a step difference is formed on the surface. In other words, when a thin copper plate is stacked on a thick copper plate, a step difference is formed on the surface of the thick copper plate for an amount corresponding to the thickness of the thin copper plate. When such a step difference is formed, the copper plate surface cannot be properly pressed during lamination pressing. 
     It is an object of the present invention to provide a wiring board that allows for a thin conductive pattern and a thick conductive pattern to be stacked on an insulative core substrate without forming a step difference and allows for the thin conductive pattern and the thick conductive pattern to be electrically connected. 
     To achieve the above object, a first aspect of the present invention is a wiring board including an insulative core substrate, a first conductive pattern, a second conductive pattern, and a conductive material. The patterned first conductive pattern is adhered to the insulative core substrate. The patterned second conductive pattern is adhered to the insulative core substrate. The second conductive pattern and the first conductive pattern are adhered to the same surface of the insulative core substrate. The second conductive pattern includes a first surface that faces toward the insulative core substrate and a second surface that is opposite to the first surface. The second conductive pattern includes a recess that opens in the first surface and a through hole that extends from the first surface to the second surface. An opening of the recess that opens in the first surface and an opening of the through hole that opens in the first surface are in communication with each other. The conductive material electrically connects the first conductive pattern and the second conductive pattern to each other. The first conductive pattern is thinner than the second conductive pattern and has a current line with a smaller cross-sectional area than that of the second conductive pattern. The first conductive pattern extends on the insulative core substrate so as to be arranged in the opening of the recess. The conductive material, which is filled into the through hole from an opening that opens in the second surface, electrically connects the first conductive pattern and the second conductive pattern. 
     A second aspect of the present invention is a wiring board provided with an insulative core substrate including a recess, a first conductive pattern, a second conductive pattern, and a conductive material. The patterned first conductive pattern is adhered to the insulative core substrate. The first conductive pattern includes a bent portion received in the recess. The patterned second conductive pattern is adhered to the insulative core substrate. The second conductive pattern and the first conductive pattern are adhered to the same surface of the insulative core substrate. The second conductive pattern extends to be arranged in an opening of the recess. The second conductive pattern includes a first surface that faces toward the insulative core substrate and a second surface that is opposite to the first surface. The second conductive pattern includes a through hole that extends from the first surface to the second surface. The through hole is located at a position corresponding to the recess. The conductive material electrically connects the first conductive material and the second conductive material to each other. The first conductive pattern is thinner than the second conductive pattern and has a current line with a smaller cross-sectional area than that of the second conductive pattern. The conductive material, which is filled into the through hole from an opening that opens in the second surface, electrically connects the first conductive pattern and the second conductive pattern. 
     A third aspect of the present invention is a wiring board including an insulative core substrate, a wiring substrate, a second conductive pattern, and a conductive material. The wiring substrate is adhered to the insulative core substrate. The wiring substrate includes a patterned first conductive pattern. The patterned second conductive pattern is adhered to the insulative core substrate. The second conductive pattern and the wiring substrate are adhered to the same surface of the insulative core substrate. The second conductive pattern includes a first surface that faces toward the insulative core substrate and a second surface that is opposite to the first surface. The second conductive pattern includes a recess that opens in the first surface and a through hole that extends from the first surface to the second surface. An opening of the recess that opens in the first surface and an opening of the through hole that opens in the first surface are in communication with each other. The conductive material electrically connects the first conductive pattern and the second conductive pattern to each other. The wiring substrate is thinner than the second conductive pattern and has a current line with a smaller cross-sectional area than that of the second conductive pattern. The first conductive pattern extends on the insulative core substrate so as to be arranged in the opening of the recess. The conductive material, which is filled into the through hole from an opening that opens in the second surface, electrically connects the first conductive pattern and the second conductive pattern. 
     A fourth aspect of the present invention is a wiring board provided with an insulative core substrate including a recess, a flexible wiring substrate, a second conductive pattern, and a conductive material. The flexible wiring substrate is adhered to the insulative core substrate. The flexible wiring substrate includes a patterned first conductive pattern. The flexible wiring substrate includes a bent portion received in the recess. The patterned second conductive pattern is adhered to the insulative core substrate. The second conductive pattern and the flexible wiring substrate are adhered to the same surface of the insulative core substrate. The second conductive pattern extends to be arranged in an opening of the recess. The second conductive pattern includes a first surface that faces toward the insulative core substrate and a second surface that is opposite to the first surface. The second conductive pattern includes a through hole that extends from the first surface to the second surface. The through hole is located at a position corresponding to the recess. A conductive material electrically connects the first conductive pattern and the second conductive pattern to each other. The flexible wiring substrate is thinner than the second conductive pattern and has a current line with a smaller cross-sectional area than that of the second conductive pattern. The conductive material, which is filled into the through hole from an opening that opens in the second surface, electrically connects the first conductive pattern and the second conductive pattern. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a plan view of an electronic device according to a first embodiment of the present invention, and  FIG. 1B  is a front view of the electronic device shown in  FIG. 1A ; 
         FIG. 2  is a bottom view of the electronic device shown in  FIG. 1A ; 
         FIG. 3A  is a cross-sectional view taken along line  3   a - 3   a  in  FIG. 1A , and  FIG. 3B  is a cross-sectional view taken along line  3   b - 3   b  in  FIG. 1A ; 
         FIG. 4A  is a plan view of the electronic device shown in  FIG. 1A  illustrating a manufacturing step, and  FIG. 4B  is a front view of the electronic device shown in  FIG. 1A  illustrating a manufacturing step; 
         FIG. 5A  is a cross-sectional view taken along line  5   a - 5   a  in  FIG. 4A , and  FIG. 5B  is a cross-sectional view taken along line  5   b - 5   b  in  FIG. 4A ; 
         FIG. 6A  is a plan view of the electronic device shown in  FIG. 1A  illustrating a manufacturing step, and  FIG. 6B  is a front view of the electronic device shown in  FIG. 1A  illustrating a manufacturing step; 
         FIG. 7A  is a cross-sectional view taken along line  7   a - 7   a  in  FIG. 6A , and  FIG. 7B  is a cross-sectional view taken along line  7   b - 7   b  in  FIG. 6A ; 
         FIG. 8A  is a plan view of an electronic device according to a second embodiment of the present invention, and  FIG. 8B  is a cross-sectional view taken along line  8   b - 8   b  in  FIG. 8A ; 
         FIG. 9A  is a plan view of the electronic device shown in  FIG. 8A  illustrating a manufacturing step, and  FIG. 9B  is a cross-sectional view taken along line  9   b - 9   b  in  FIG. 9A ; 
         FIG. 10A  is a plan view of the electronic device shown in  FIG. 8A  illustrating a manufacturing step, and  FIG. 10B  is a cross-sectional view taken along line  10   b - 10   b  in  FIG. 10A ; 
         FIG. 11A  is a plan view of the electronic device shown in  FIG. 8A  illustrating a manufacturing step, and  FIG. 11B  is a cross-sectional view taken along line  11   b - 11   b  in  FIG. 11A ; 
         FIG. 12A  is a plan view showing a further example of an electronic device, and  FIG. 12B  is a front view of the electronic device shown in  FIG. 12A ; 
         FIG. 13A  is a bottom view of the electronic device shown in  FIG. 12A ,  FIG. 13B  is a cross-sectional view taken along line  13   b - 13   b  in  FIG. 12A , and  FIG. 13C  is a cross-sectional view taken along line  13   c - 13   c  in  FIG. 12A ; and 
         FIG. 14A  is a plan view showing a further example of an electronic device, and  FIG. 14B  is a cross-sectional view taken along line  14   b - 14   b  in  FIG. 14A . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     A first embodiment of the present invention will now be described with reference to the drawings. 
     As shown in  FIGS. 1A to 3B , an electronic device  10  includes a wiring board  20 . The wiring board  20  includes an insulative core substrate  30 , a thin copper plate  40  adhered to one surface (upper surface) of the insulative core substrate  30  by an adhesive sheet  70 , a thick copper plate  50  adhered to one surface (upper surface) of the insulative core substrate  30  by the adhesive sheet  70 , and a thick copper plate  60  adhered to the other surface (lower surface) of the insulative core substrate  30 . 
     More specifically, in the wiring board  20 , the copper plate  40 , which serves as a patterned thin metal plate, and the copper plate  50 , which serves as a patterned thick metal plate, are adhered to the same surface of the insulative core substrate  30 . Further, the thick copper plate  60 , which serves as a patterned rear surface metal plate, is adhered to the surface (lower surface) of the insulative core substrate  30  opposite to the surface (upper surface) to which the thin copper plate  40  and the thick copper plate  50  are adhered. 
     The thin copper plate  40  has a thickness of, for example, approximately 100 μm, and the thick copper plate  50  has a thickness of, for example, approximately 400 μm. Further, the thick copper plate  60  has a thickness of, for example, approximately 400 μm. A large current may flow through the thick copper plates  50  and  60 , and a small current may flow through the thin copper plate  40 . 
     The thin copper plate  40 , the thick copper plate  50 , and the thick copper plate  60  are each pressed and adhered to the insulative core substrate. 
     As shown in  FIG. 2 , the thick copper plate  60  includes an annular conductive pattern  61 , and the conductive pattern  61  forms a primary coil of a transformer. In the same manner, as shown in  FIG. 1A , the thick copper plate  50  includes an annular conductive pattern  51 , and the conductive pattern  51  forms a secondary coil of a transformer. The annular conductive pattern  61  (primary coil) and the conductive pattern  51  (secondary coil) are arranged at the same position on the two surfaces of the insulative core substrate  30 . 
     As shown in  FIG. 1A , the thick copper plate  50  includes a rectangular conductive pattern  52 . The conductive pattern  52  forms a wire that extends from one end of the secondary coil of the transformer. In the same manner, the thick copper plate  50  includes a rectangular conductive pattern  53 . The conductive pattern  53  forms a wire that extends from the other end of the secondary coil of the transformer. 
     In  FIGS. 1A and 1B , reference character  55  denotes another conductive pattern of the thick copper plate  50 . 
     As shown in  FIG. 1A , the thin copper plate  40  includes a conductive pattern  41  that extends from the conductive pattern  52 . Further, the thin copper plate  40  includes a conductive pattern  42  that extends from the conductive pattern  53 . The conductive patterns  41  and  42  form an energizing current detection line for the secondary coil of the transformer or a voltage detection line for the secondary coil of the transformer. 
     In this manner, in the wiring board  20 , the patterned first conductive patterns  41  and  42  and the patterned second conductive patterns  51 ,  52 , and  53  are adhered to the same surface of the insulative core substrate  30 . Further, the first conductive patterns  41  and  42  are thinner than the second conductive patterns  51 ,  52 , and  53  and have a current line with a smaller cross-sectional area than the second conductive patterns  51 ,  52 , and  53 . 
     As shown in  FIGS. 1A and 3B , the conductive pattern  52  includes a circular through hole  80 . Further, as shown in  FIGS. 1A and 3A , the conductive pattern  52  includes a recess  85 . The recess  85  extends straight from one side surface of the conductive pattern  52  to the through hole  80 . The recess  85  is formed so that a portion near the insulative core substrate  30  is open. In this manner, the second conductive pattern  52  includes the recess  85 , which is formed so that a portion near the insulative core substrate  30  is open, and the through hole  80 , which opens in a portion near the insulative core substrate  30  and a portion at the opposite side of the portion near the insulative core substrate  30 . Further, the opening of the recess  85  near the insulative core substrate  30  and the opening of the through hole  80  near the insulative core substrate  30  are formed to be connected to each other. 
     The conductive pattern  41  is arranged in the opening of the recess  85  and the opening of the through hole  80  near the insulative core substrate  30 . That is, the first conductive pattern  41  passes through the opening of the recess  85  near the insulative core substrate  30  and extends to the opening of the through hole  80  near the insulative core substrate  30 . Further, as shown in  FIGS. 1A and 3B , the through hole  80  is filled with solder  90 , which serves as a conductive material. The solder  90  electrically connects the conductive pattern  41  of the thin copper plate  40  and the conductive pattern  52  of the thick copper plate  50 . In other words, the solder  90 , which serves as a conductive material filled from an opening of the through hole  80  opposite to the opening near the insulative core substrate  30 , electrically connects the first conductive pattern  41  and the second conductive pattern  52 . 
     In the same manner, the conductive pattern  53  includes a circular through hole  81 . Further, the conductive pattern  53  includes a recess  86 . The recess  86  extends straight from one side surface of the conductive pattern  53  to the through hole  81 . The recess  86  is formed so that a portion near the insulative core substrate  30  is open. In this manner, the second conductive pattern  53  includes the recess  86 , which is formed so that a portion near the insulative core substrate  30  is open, and the through hole  81 , which opens in a portion near the insulative core substrate  30  and a portion at the opposite side of the portion near the insulative core substrate  30 . Further, the opening of the recess  85  near the insulative core substrate  30  and the opening of the through hole  81  near the insulative core substrate  30  are formed to be connected to each other. 
     The conductive pattern  42  is arranged in the opening of the recess  86  and the opening of the through hole  81  near the insulative core substrate  30 . That is, the first conductive pattern  42  passes through the opening of the recess  86  near the insulative core substrate  30  and extends to the opening of the through hole  81  near the insulative core substrate  30 . Further, the through hole  81  is filled with solder  91 , which serves as a conductive material. The solder  91  electrically connects the conductive pattern  42  of the thin copper plate  40  and the conductive pattern  53  of the thick copper plate  50 . In other words, the solder  91 , which serves as a conductive material filled from an opening of the through hole  81  opposite to the opening near the insulative core substrate  30 , electrically connects the first conductive pattern  42  and the second conductive pattern  53 . 
     In this manner, the conductive patterns  52  and  53  of the thick copper plate  50  for a large current are connected to the conductive patterns  41  and  42  of the thin copper plate  40  for a small current. 
     As shown in  FIGS. 1A and 3A , the conductive pattern  52  of the thick copper plate  50  includes a recess  87 . The recess extends straight from one side surface to the other side surface. The recess  87  is formed so that a portion near the insulative core substrate  30  is open. The conductive pattern  42  of the thin copper plate  40  is arranged in the opening of the recess  87  in a non-contact state. 
     The recesses  85 ,  86 , and  87  may be formed by performing a pressing process on the thick copper plate  50 . The depths of the recesses  85 ,  86 , and  87  are greater than the thickness of the thin copper plate  40 . 
     The operation of the wiring board will now be described. 
     As shown in  FIGS. 4A to 5B , the thin copper plate  40  is adhered to the upper surface of the insulative core substrate  30  by the adhesive sheet  70  in a first pressing process. The thin copper plate  40  is patterned. 
     Then, as shown in  FIGS. 6A to 7B , the thick copper plate  50  is adhered to the upper surface of the insulative core substrate  30  by the adhesive sheet  70  in a second pressing process. Here, the thick copper plate  50  is patterned, and the through holes  80  and  81  and the recesses  85 ,  86 , and  87  are formed in the conductive patterns  52  and  53 . Then, when the conductive pattern  41  is located in the opening of the through hole  80  and the opening of the recess  85  and the conductive pattern  42  is located in the opening of the through hole  81  and the openings of the recesses  86  and  87 , the thick copper plate  50  is adhered to the upper surface of the insulative core substrate  30 . 
     Further, the thick copper plate  60  is simultaneously adhered to the lower surface of the insulative core substrate  30  by the adhesive sheet  71  during the second pressing process. The thick copper plate  60  is patterned. 
     As shown in  FIGS. 1A to 3B , the through holes  80  and  81  are filled with the solders  90  and  91  that serve as the conductive material. The solder  90  electrically connects the conductive pattern  41  and the conductive pattern  51 . The solder  91  electrically connects the conductive pattern  42  and the conductive pattern  53 . 
     The solders  90  and  91  may be formed (filled in the through holes  80  and  81 ) by directly dropping solder into the through holes  80  and  81  or by arranging a solder paste through printing in the through holes  80  and  81  and performing a reflow process. 
     As discussed above, the recesses  85 ,  86 , and  87  are formed in the secondary coil pattern (conductive patterns  52  and  53 ) of the thick copper plate  50 , and the secondary current detection conductive pattern or the voltage detection conductive pattern (conductive patterns  41  and  42 ) of the thin copper plate  40  are extended through the recesses  85 ,  86 , and  87 . This omits step differences from the surface. 
     More specifically, the conductive patterns  41  and  42  of the thin copper plate  40  are arranged in the openings of the recesses  85 ,  86 , and  87  in the conductive patterns  52  and  53  of the thick copper plate  50 . When the conductive patterns  41  and  42  of the thin copper plate  40  and the conductive patterns  52  and  53  of the thick copper plate  50  are arranged on the insulative core substrate  30 , step differences are not formed in the surface of the conductive patterns  52  and  53 . 
     Further, the conductive patterns  41  and  42  of the thin copper plate  40  are arranged in the opening of the through holes  80  and  81  in the conductive patterns  52  and  53  of the thick copper plate  50 . The solders  90  and  91  filled in the through holes  80  and  81  electrically connect the conductive patterns  41  and  42  to the conductive patterns  52  and  53 . 
     The present embodiment has the advantages described below. 
     (1) The second conductive patterns  52  and  53  include the recesses  85  and  86 , which open in portions near the insulative core substrate  30 , and the through holes  80  and  81 , which open in portions near the insulative core substrate  30  and portions opposite to the portions near the insulative core substrate  30 . In other words, the second conductive patterns  52  and  53  includes a first surface facing toward the insulative core substrate  30  and a second surface opposite to the first surface. The second conductive pattern includes the recesses  85  and  86 , which open in the first surface, and the through holes  80  and  81 , which extend from the first surface to the second surface. Further, the openings near the insulative core substrate  30  of the recesses  85  and  86  and the opening of the through holes  80  and  81  near the insulative core substrate  30  are formed to be connected to each other. In other words, the recesses  85  and  86  that open in the first surface and the openings of the through holes  80  and  81  that open in the first surface are in communication with each other. The first conductive patterns  41  and  42  are arranged to extend along portions corresponding to the recesses  85  and  86  in the insulative core substrate  30 . That is, the first conductive patterns  41  and  42  are arranged in openings of the recesses  85  and  86  near the insulative core substrate  30 . In other words, the first conductive patterns  41  and  42  extend on the insulative core substrate  30  to be arranged in the openings of the recesses  85  and  86 . Further, the solders  90  and  91 , which serve as conductive material that is filled in the through holes  80  and  81  from the openings near the insulative core substrate  30  and the opposite openings, electrically connect the first conductive patterns  41  and  42  and the second conductive patterns  52  and  53 . In other words, the solders  90  and  91  filled from the openings of the through holes  80  and  81 , which open in the second surface, electrically connect the first conductive patterns  41  and  42  to the second conductive patterns  52  and  53 . 
     As a result, the thin conductive patterns  41  and  42  and the thick conductive patterns  52  and  53  may be stacked on the insulative core substrate  30  without forming step differences. This allows for the surface to be pressed during a pressing process. Further, the thin conductive patterns  41  and  42  and the thick conductive patterns  52  and  53  may be electrically connected. 
     In the prior art, when patterned copper plates are adhered to an insulative core substrate to form a substrate (wiring board), step differences are formed in the surface when stacking a thin copper plate and a thick copper plate on the insulative core substrate, and the copper plate surface cannot be properly pressed during lamination pressing. In contrast, the present embodiment adheres the thin copper plate  40  in the first pressing process and adheres the thick copper plates  50  and  60  in the second pressing process. This allows for electric connections to be obtained. 
     In the present embodiment, the first conductive patterns  41  and  42  extend on the insulative core substrate  30  from openings of the recesses  85  and  86  near the insulative core substrate  30  to openings of the through holes  80  and  81  near the insulative core substrate  30 . Instead, the first conductive patterns  41  and  42  may extend on the insulative core substrate  30  from openings of the recesses  85  and  86  near the insulative core substrate  30  but not reach openings of the through holes  80  and  81  near the insulative core substrate  30 . It is only necessary that the first conductive patterns  41  and  42  be arranged on the insulative core substrate  30  in openings of the recesses  85  and  86  near the insulative core substrate  30  and that the solders  90  and  91 , which are filled from the openings of the through holes  80  and  81  opposite to the openings near the insulative core substrate  30 , electrically connect the first conductive patterns  41  and  42  to the second conductive patterns  52  and  53 . 
     (2) The thick copper plate  60 , which serves as a patterned rear metal plate, is adhered to surface of the insulative core substrate  30  opposite to the surface to which the first conductive patterns  41  and  42  and the second conductive patterns  52  and  53  are adhered. This allows for the wiring board  20  to be a double-surface substrate. 
     (3) The conductive pattern  61  of the copper plate  60  forms the primary coil of the transformer, and the second conductive pattern  51  forms the secondary coil of the transformer. This allows for the transformer to be formed with coils on the two surfaces of the substrate. 
     (4) The first conductive patterns  41  and  42  form current or voltage detection lines in the secondary coil of the transformer. This allows for a structure that detects the current or voltage of the transformer to be easily formed. 
     Second Embodiment 
     A second embodiment will now be described focusing on differences from the first embodiment. 
     In  FIGS. 1A to 3B , the insulative core substrate  30  has a flat upper surface. In the present embodiment, as shown in  FIGS. 8A and 8B , a wiring board  100  is provided with an insulative core substrate  110  of which an upper surface includes a tetragonal recess  111 . 
     In the wiring board  100 , a patterned first conductive pattern  121  and a patterned second conductive pattern  131  are adhered to the insulative core substrate  110  on the same surface. The conductive pattern  121 , which is formed by a thin copper plate  120  serving as a thin metal plate, extends straight with a fixed width. Further, the conductive pattern  131 , which is formed by a thick copper plate  130  serving as a thick metal plate, extends straight with a fixed width. 
     The first conductive pattern  121  is thinner than the second conductive pattern  131  and has a current line with a smaller cross-sectional area than the second conductive pattern  131 . Further, the first conductive pattern  121  includes a bent portion  121   a.    
     The insulative core substrate  110  includes the recess  111  that receives the bent portion  121   a . The recess  111  has a depth that is greater than the thickness of the thin copper plate  120 . 
     The second conductive pattern  131  is arranged in the opening of the recess  111 . A portion of the second conductive pattern  131  corresponding to the opening of the recess  111  includes a through hole  140 . The through hole  140  opens in a portion near the insulative core substrate  110  and a portion opposite to the portion near the insulative core substrate  110 . In other words, the second conductive pattern  131  has a first surface facing toward the insulative core substrate  110  and a second surface opposite to the first surface. The second conductive pattern  131  includes a through hole  140  extending from the first surface to the second surface. The through hole  140  is located at a position corresponding to the recess  111 . 
     In the portion where the recess  111  is formed, the thin conductive pattern  121  and the thick conductive pattern  131  intersect each other, and the conductive pattern  121  and the conductive pattern  131  are electrically connected. That is, the solder  150 , which serves as a conductive material filled from an opening of the through hole  140  opposite to the insulative core substrate  110 , electrically connects the first conductive pattern  121  and the second conductive pattern  131 . 
     As shown in  FIGS. 8A and 8B , the patterned thin copper plate  120  and the patterned thick copper plate  130  are adhered by an adhesive sheet  160  to the upper surface (same surface) of the insulative core substrate  110 . The thin copper plate  120  and the thick copper plate  130  are adhered to the insulative core substrate  110  in a pressing process. 
     A method for manufacturing the wiring board will now be described. 
     The manufacturing process will first be described. 
     As shown in  FIGS. 9A and 9B , the insulative core substrate  110  including the recess  111  in the upper surface is first prepared. As shown in  FIGS. 10A and 10B , the thin copper plate  120  is adhered to the upper surface of the insulative core substrate  110  by the adhesive sheet  160  in a first pressing process. The thin copper plate  40  is adhered to the upper surface of the insulative core substrate  110  so that the conductive pattern  121  is received in the recess  111 . 
     Then, as shown in  FIGS. 11A and 11B , the thick copper plate  130  is adhered to the upper surface of the insulative core substrate  110  by the adhesive sheet  160  in a second pressing process. The thick copper plate  130  is patterned and includes the through hole  140 . The conductive pattern  131  of the thick copper plate  130  is arranged in the opening of the recess  111 , and the thick copper plate  130  is adhered to the upper surface of the insulative core substrate  110  so that the through hole  140  is located in the opening of the recess  111 . 
     As shown in  FIGS. 8A and 8B , the through hole  140  is filled with the solder  150 , which serves as a conductive material. The solder  150  electrically connects the conductive pattern  121  of the thin copper plate  120  and the conductive pattern  131  of the thick copper plate  130 . 
     In this manner, the conductive pattern  121  of the thin copper plate  120  is received in the recess  111  of the insulative core substrate  110 , and the conductive pattern  121  of the thin copper plate  120  and the conductive pattern  131  of the thick copper plate  130  are stacked and arranged on the insulative core substrate  110 . Here, the surface may be pressed during a pressing process without forming a step difference in the surface of the conductive pattern  131  in the thick copper plate  130 . Further, the solder  150 , which is filled in the through hole  140  formed in the conductive pattern  131  that is arranged in the recess  111 , electrically connects the conductive pattern  121  and the conductive pattern  131 . 
     As a result, the thin conductive pattern  121  and the thick conductive pattern  131  may be alternatively stacked and arranged on the insulative core substrate  110  without forming step differences. Further, the thin conductive pattern  121  and the thick conductive pattern  131  may be electrically connected. 
     The embodiments are not limited to the foregoing description and may be applied as described below. 
     Instead of  FIGS. 1A to 2 , the structure shown in  FIGS. 12A to 13C  may be employed. As shown in  FIGS. 12A and 12B , a wiring substrate  200  is used. As shown in  FIGS. 13B and 13C , the wiring substrate  200  includes an insulation film  200   a  and a copper pattern  200   b  adhered onto the insulation film  200   a . In the wiring board  20 , a wiring substrate  200 , which includes patterned first conductive patterns  201  and  202 , and patterned second conductive patterns  51 ,  52 , and  53  are adhered to the same surface of the insulative core substrate  30 . The wiring substrate  200  is thinner than the second conductive patterns  51 ,  52 , and  53  and has a current line with a smaller cross-sectional area than the second conductive patterns  51 ,  52 , and  53 . The second conductive patterns  51 ,  52 , and  53  include recesses  85  and  86 , which open in portions near the insulative core substrate  30 , and through holes  80  and  81 , which open in portions opposite to the portions near the insulative core substrate  30 . The openings of the recesses  85  and  86  near the insulative core substrate  30  are formed to be connected to the openings of the through holes  80  and  81  near the insulative core substrate  30 . The first conductive patterns  201  and  202  extend on the insulative core substrate  30  through the openings of the recesses  85  and  86  near the insulative core substrate  30  to the openings of the through holes  80  and  81  near the insulative core substrate  30 . In broad terms, the first conductive patterns  201  and  202  are arranged on the insulative core substrate  30  in the openings of the recesses  85  and  86  near the insulative core substrate  30 . In this case, step differences are not formed in the surfaces of the thick second conductive patterns  51 ,  52 , and  53 . The solders  90  and  91 , which serve as a conductive material filled into the through holes  80  and  81  from openings opposite the openings near the insulative core substrate  30 , electrically connect the first conductive patterns  201  and  202  to the second conductive patterns  52  and  53 . 
     In this manner, the thin conductive patterns  201  and  202  and the thick conductive patterns  52  and  53  may be stacked and arranged on the insulative core substrate  30  without forming step differences. Further, the thin conductive patterns  201  and  202  may be electrically connected to the thick conductive patterns  52  and  53 . 
     Instead of  FIGS. 8A and 8B , the structure shown in FIGS.  14 A and  14 B may be employed. As shown in  FIGS. 14A and 14B , a flexible wiring substrate  300  is used. The flexible wiring substrate  300  includes an insulation film  300   a  and a copper pattern  300   b , which is adhered onto the insulation film  300   a . In a wiring board  100 , the flexible wiring substrate  300 , which includes a patterned first conductive pattern  301 , and a patterned second conductive pattern  131  are adhered to the same surface of the insulative core substrate  110 . The flexible wiring substrate  300  is thinner than the second conductive pattern  131  and has a current line with a smaller cross-sectional area than the second conductive pattern  131 . The flexible wiring substrate  300  includes a bent portion  310 . The insulative core substrate  110  includes the recess  111  that receives the bent portion  310 . The second conductive pattern  131  is arranged in the opening of the recess  111 . A portion of the second conductive pattern  131  corresponding to the opening of the recess  111  in the second conductive pattern  131  includes a through hole  140 . The through hole  140  opens in a portion near the insulative core substrate  110  and a portion opposite to the portion near the insulative core substrate  110 . Step differences are not formed in the surface of the second conductive pattern  131 . Solder  150 , which serves as a conductive material filled into the through hole  140  from an opening opposite to the insulative core substrate  110 , electrically connects the first conductive pattern  301  and the second conductive pattern  131 . 
     In this manner, the thin conductive pattern  301  and the thick conductive pattern  131  may be stacked and arranged on the insulative core substrate  110  without forming step differences. Further, the thin conductive pattern  301  and the thick conductive pattern  131  may be electrically connected. 
     Copper plates ( 40 ,  50 ,  60 ,  120 ,  130 , etc.) are used as the metal plates. However, other metal plates such as aluminum plates may be used as the metal plates. Preferably, soldered regions undergo a plating process when using aluminum plates. 
     Solder ( 90 ,  91 , and  150 ) is used as the conductive material. Instead, other metals having low melting points may be used.