Patent Publication Number: US-11657945-B2

Title: Laminated inductor component

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims benefit of priority to Japanese Patent Application No. 2017-240004, filed Dec. 14, 2017, the entire content of which is incorporated herein by reference. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a laminated inductor component including a plurality of coil conductor layers disposed on a plurality of laminated insulator layers. 
     Background Art 
     Japanese Patent No. 5821535 discloses, as a laminated inductor having a high quality factor (Q factor). The laminated inductor includes a plurality of coil conductor layers (inner conductor layers) wound on an insulator layer in a multilayer body, and provided with a helical coil conductor (coil structure) having a coil length parallel to the lamination direction and an L-shaped outer conductor exposed from a side surface and a bottom surface (a mounting substrate surface) of the multilayer body, where the coil length is parallel (in a lateral direction) with respect to the bottom surface and the side surface. Note that “coil length” refers to a coil conductor length along a direction in which the helical coil conductor extends while being wound. Alternatively, “coil length” may be a coil conductor length along a winding center line (coil axis) of the helical coil conductor. 
       FIG.  7    is a cross-sectional view illustrating the laminated inductor of Japanese Patent No. 5821535, and represents a cross section parallel to a bottom surface. In the laminated inductor of Japanese Patent No. 5821535, a first outer conductor  3   a  and a second outer conductor  3   b  are respectively exposed from a first side surface  5   a  and a second side surface  5   b  opposing each other. The first outer conductor  3   a  and the second outer conductor  3   b  are also exposed from the bottom surface (not illustrated). A multilayer body  2  is laminated in a lamination direction L (an up-down direction in  FIG.  7   ) along the first side surface  5   a , the second side surface  5   b , and the bottom surface; a main surface on an outer side portion of an outermost layer  6   a  and a main surface on an outer side portion of an outermost layer  6   b  of the multilayer body  2  constitute a third side surface  7   a  and a fourth side surface  7   b , respectively, of the multilayer body  2 . 
     A coil conductor  1  has a coil length CL parallel to the lamination direction L. The first outer conductor  3   a  and the second outer conductor  3   b  are covered with a metal layer  4  which is plating of nickel Ni and tin Sn, and constitute an outer electrode  8 . 
     SUMMARY 
     In the laminated inductor component of  FIG.  7   , it is conceivable to increase an aspect ratio of a coil conductor layer  9  in order to further enhance the Q factor. In this case, the thickness of the coil conductor layer  9  (length along the lamination direction L in a cross section of the coil conductor layer  9 ) increases. However, in a case where it is attempted to achieve this increase without changing an outer shape dimension of the multilayer body  2 , since the rate of the coil length CL of the coil conductor  1  in the multilayer body  2  increases, a thickness “a” of each of the outermost layers  6   a  and  6   b  of the multilayer body  2  becomes small, as illustrated in  FIG.  8   . 
     Note that, since the coil conductor layer  9 , the first outer conductor  3   a , and the second outer conductor  3   b  are usually formed on the same insulation layer, the width of each of the first outer conductor  3   a  and the second outer conductor  3   b  along the lamination direction L is equal to the coil length CL, and the thickness of each of the outermost layers  6   a  and  6   b  positioned respectively above and below the first outer conductor  3   a  and the second outer conductor  3   b  is equal to “a”. Under this state, in a case where the metal layer  4  is formed on the first outer conductor  3   a  and the second outer conductor  3   b , there is a high possibility that the metal layer  4  is extended from the first side surface  5   a , the second side surface  5   b , and the bottom surface of the multilayer body  2  onto the third side surface  7   a  side or the fourth side surface  7   b  side. 
     In the case where the metal layer  4  extends onto the third side surface  7   a  side or the fourth side surface  7   b  side, a variation in an outer diameter dimension along the lamination direction L of the laminated inductor increases. Thus, for example, a problem that the mounting device fails to correctly take out the laminated inductor from the packaging material in the mounting process is likely to occur, thereby making it difficult to smoothly mount the laminated inductor. Alternatively, such a problem is likely to occur that the laminated inductor is in contact with or to be short-circuited with a component mounted adjacent to the laminated inductor on the lamination direction L side on the mounting substrate. 
     Further, even in a case where the metal layer  4  does not extend onto the third side surface  7   a  side or the fourth side surface  7   b  side, mounting solder that adheres to the metal layer  4  at the time of mounting may extend onto the third side surface  7   a  side or the fourth side surface  7   b  side. Due to this, the mounting solder may cause a trouble of making contact with or being short-circuited with a component mounted adjacent to the laminated inductor on the lamination direction L side on the mounting substrate. In other words, a variation in a substantial outer shape dimension with the attached mounting solder of the laminated inductor increases. 
     Further, as illustrated in  FIG.  9   , even in a case where the first outer conductor  3   a  and the second outer conductor  3   b  are not formed, and an extended electrode  10  continued from an end portion of the coil conductor  1  is exposed to the first side surface  5   a  and the second side surface  5   b  of the multilayer body  2 , by increasing the aspect ratio without changing the outer shape dimension of the multilayer body  2 , a distance from an exposed position of the extended electrode  10  to the third side surface  7   a  or the fourth side surface  7   b , that is, the thickness of the outermost layer  6   a  or  6   b  of the multilayer body  2  is reduced. As a result, in the case where the metal layer  4  is so formed as to cover the exposed portion of the extended electrode  10 , the mounting solder is attached to the metal layer  4 , or the like, similar problems to those illustrated in  FIG.  8    are likely to occur. 
     In view of the foregoing, the present disclosure provides a laminated inductor component capable of reducing a variation in the substantial outer shape dimension. 
     An aspect of a laminated inductor component includes a multilayer body which includes a first side surface and a second side surface opposing each other, and a bottom surface connecting the first side surface and the second side surface, and in which a plurality of insulator layers is laminated in a lamination direction along the first side surface, the second side surface, and the bottom surface. The laminated inductor component further includes a coil conductor in helical form including a plurality of coil conductor layers wound on the insulator layers, and having a coil length parallel to the lamination direction; a first outer conductor electrically connected to a first end of the coil conductor and exposed from the first side surface and the bottom surface in the multilayer body; and a second outer conductor electrically connected to a second end of the coil conductor and exposed from the second side surface and the bottom surface in the multilayer body. A width along the lamination direction of each of the first outer conductor and the second outer conductor is shorter than the coil length. 
     This configuration suppresses a situation in which the metal layer covering the first outer conductor and the second outer conductor or the mounting solder attached thereto extend onto the side surface on the lamination direction side of the multilayer body. 
     In addition, in the above-described laminated inductor component, it is preferable that, when viewed from a direction orthogonal to the first side surface, an end portion of the first outer conductor on the first end side in the lamination direction overlap with part of the coil conductor layer to be an outermost layer on the first end side. With this configuration, since it is possible to simultaneously form the end portion of the first outer conductor and part of the coil conductor layer overlapping with each other on the first end side, dimensional accuracy of a width along the lamination direction of the first outer conductor is enhanced with respect to the coil length of the coil conductor. 
     Meanwhile, in the laminated inductor component, it is preferable that, when viewed from the direction orthogonal to the first side surface, an end portion of the first outer conductor on the second end side in the lamination direction overlap with part of the coil conductor layer to be an outermost layer on the second end side. With this configuration, since it is possible to simultaneously form the end portion of the first outer conductor and part of the coil conductor layer overlapping with each other on the second end side, the dimensional accuracy of the width along the lamination direction of the first outer conductor is further enhanced with respect to the coil length of the coil conductor. 
     In addition, in the laminated inductor component, it is preferable that the stated laminated inductor component further include an extended electrode connecting the first end and the first outer conductor, and that a thickness on the first end side of the extended electrode be greater than a thickness on the first outer conductor side of the extended electrode. Further, it is preferable that a step having a different thickness be formed on the extended electrode. This configuration makes it possible to easily shorten the width along the lamination direction of the first outer conductor compared to the coil length. 
     In addition, in the laminated inductor component, it is preferable that a line width of the extended electrode be wider than a line width of the coil conductor layer. With this configuration, reduction in a cross-sectional area of the extended electrode is canceled, and an increase in local electric resistance in the extended electrode can be suppressed. 
     Another aspect of a laminated inductor component includes a multilayer body which includes a first side surface and a second side surface opposing each other, and a bottom surface connecting the first side surface and the second side surface, and in which a plurality of insulator layers is laminated in a lamination direction along the first side surface, the second side surface, and the bottom surface. The laminated inductor component further includes a coil conductor in helical form including a plurality of coil conductor layers wound on the insulator layers, and having a coil length parallel to the lamination direction; a first outer conductor electrically connected to a first end of the coil conductor and exposed from the first side surface and the bottom surface in the multilayer body; and a second outer conductor electrically connected to a second end of the coil conductor and exposed from the second side surface and the bottom surface in the multilayer body. Both ends in the lamination direction of the first outer conductor and the second outer conductor are positioned on an inner side relative to both ends in the lamination direction of the coil conductor. 
     This configuration suppresses a situation in which the metal layer covering the first outer conductor and the second outer conductor, the mounting solder attached thereto, and the like extend onto the side surface on the lamination direction side of the multilayer body. 
     Another aspect of the laminated inductor component includes a multilayer body which includes a first side surface and a second side surface opposing each other, and a bottom surface connecting the first side surface and the second side surface, and in which a plurality of insulator layers is laminated in a lamination direction along the first side surface, the second side surface, and the bottom surface. The laminated inductor component further includes a coil conductor in helical form including a plurality of coil conductor layers wound on the insulator layers, and having a coil length parallel to the lamination direction; a first outer conductor electrically connected to a first end of the coil conductor and exposed from the bottom surface in the multilayer body; and a second outer conductor electrically connected to a second end of the coil conductor and exposed from the bottom surface in the multilayer body. A width along the lamination direction of each of the first outer conductor and the second outer conductor is shorter than the coil length. 
     This configuration suppresses a situation in which the metal layer covering the first outer conductor and the second outer conductor, the mounting solder attached thereto, and the like extend onto the side surface on the lamination direction side of the multilayer body. 
     In addition, in the laminated inductor component, it is preferable that the stated laminated inductor component further include a metal layer covering the first outer conductor, and that both ends in the lamination direction of the metal layer be positioned in the bottom surface. With this configuration, the metal layer does not extend onto the side surface on the lamination direction side of the multilayer body, and a situation in which the mounting solder attached to the metal layer extends onto the side surface on the lamination direction side of the multilayer body can be further suppressed. 
     Other features, elements, characteristics and advantages of the present disclosure will become more apparent from the following detailed description (with reference to the attached drawings). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional view illustrating a laminated inductor component; 
         FIGS.  2 A to  2 Q  are explanatory diagrams illustrating a lamination process of a laminated inductor component; 
         FIG.  3    is an explanatory diagram showing a transition of a Q factor based on changes in an outer layer thickness and a line width of a coil conductor; 
         FIGS.  4 A to  4 C  are cross-sectional views illustrating variations; 
         FIG.  5    is a front view illustrating a laminated inductor component; 
         FIGS.  6 A and  6 B  are explanatory diagrams illustrating a production method for a step; 
         FIG.  7    is a cross-sectional view illustrating an existing laminated inductor component; 
         FIG.  8    is a cross-sectional view illustrating an existing laminated inductor component; and 
         FIG.  9    is a cross-sectional view illustrating an existing laminated inductor component. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, an embodiment as an aspect of the present disclosure will be described with reference to the accompanying drawings. 
     In a laminated inductor component of the present embodiment illustrated in  FIGS.  1  and  5   , a plurality of coil conductor layers  23  and a plurality of insulator layers  24  are laminated by repeating, for example, a screen printing process and a photolithography process, thereby constituting a substantially rectangular parallelepiped multilayer body  11  including a first side surface  25   a  and a second side surface  25   b  opposing each other, and a bottom surface  25   c  connecting the first side surface  25   a  and the second side surface  25   b . Further, there are provided a third side surface  25   d  and a fourth side surface  25   e  opposing each other in a direction orthogonal to a direction in which the first side surface  25   a  and the second side surface  25   b  oppose each other. 
     Each coil conductor layer  23  is electrically connected through a via  14  passing through the insulator layer  24  to configure a coil conductor  12  in helical form. In outermost layers  23   a  and  23   b  of the coil conductor layer  23 , a first outer conductor  13   a  exposed to the first side surface  25   a  is connected to a first end of the coil conductor  12 , which is an end portion of one outermost layer, that is, the outermost layer  23   a . Further, a second outer conductor  13   b  exposed to the second side surface  25   b  is connected to a second end of the coil conductor  12 , which is an end portion of the other outermost layer, that is, the outermost layer  23   b.    
     The first outer conductor  13   a  and the second outer conductor  13   b  are laminated in parallel with the lamination of the coil conductor layers  23  in a lamination process of the coil conductor layers  23 . The first end of the coil conductor  12  is connected to the first outer conductor  13   a  via an extended electrode  15   a , and the second end of the coil conductor  12  is connected to the second outer conductor  13   b  via an extended electrode  15   b.    
     In order to increase the aspect ratio, a thickness t 1  of the coil conductor layer  23  in the lamination direction (up-down direction in  FIG.  1   ) along the first side surface  25   a  and the second side surface  25   b  is sufficiently secured, and is thicker than a thickness t 2  of each of outermost layers  24   a  and  24   b  of the insulator layer  24 . Widths of the first and second outer conductors  13   a  and  13   b  along the lamination direction have the same width, that is, a width d 1 , which is shorter than a coil length d 2  of the coil conductor  12 . In other words, a step g is interposed between the outermost layer  23   a  of the coil conductor layer  23  and the first outer conductor  13   a , and an end portion in the lamination direction of the first outer conductor  13   a  is positioned on an inner side in the lamination direction relative to the outermost layer  23   a  of the coil conductor layer  23 . Accordingly, the width d 1  of the first outer conductor  13   a  is shorter in the lamination direction than the coil length d 2  of the coil conductor  12 . 
     Similarly, another step g is interposed between the outermost layer  23   b  of the coil conductor layer  23  and the second outer conductor  13   b , and an end portion in the lamination direction of the second outer conductor  13   b  is so formed as to be positioned on an inner side in the lamination direction relative to the outermost layer  23   b  of the coil conductor layer  23 . Accordingly, the width of the second outer conductor  13   b  is shorter in the lamination direction than the coil length d 2  of the coil conductor  12 . 
     Further, since the width d 1  of each of the first outer conductor  13   a  and the second outer conductor  13   b  is shorter than the coil length d 2 , a distance d 3  between the third side surface  25   d  and the end portion in the lamination direction of each of the first outer conductor  13   a  and the second outer conductor  13   b  is greater than the thickness t 2  of the outermost layer  24   b  of the insulator layer  24 . Also, a distance d 3  between the fourth side surface  25   e  and the end portion in the lamination direction of each of the first outer conductor  13   a  and the second outer conductor  13   b  is greater than the thickness t 2  of the outermost layer  24   a  of the insulator layer  24 . With this configuration, when viewed from a direction orthogonal to the first side surface  25   a  or the second side surface  25   b , both the end portions in the lamination direction of each of the first outer conductor  13   a  and the second outer conductor  13   b  overlap with part of each of the outermost layers  23   a  and  23   b  of the coil conductor layer  23 . 
     As illustrated in  FIG.  1   , a metal layer  16  plated with, for example, nickel Ni and tin Sn is formed on the first outer conductor  13   a  exposed to the first side surface  25   a  and the second outer conductor  13   b  exposed to the second side surface  25   b . The metal layer  16  may be formed of silver Ag, copper Cu, lead Pd, gold Au, or the like. Further, the insulator layer  24  is formed of a ceramic material such as glass, ferrite or alumina, or a resin, etc., and the coil conductor  12  is formed of a good conductor such as silver Ag, copper Cu, or gold Au. 
     As described above, since the width d 1  of each of the first outer conductor  13   a  and the second outer conductor  13   b  is formed to be shorter than the coil length d 2 , the metal layer  16  is accommodated within the first side surface  25   a  and the second side surface  25   b , and therefore, the metal layer  16  is unlikely to extend onto the third side surface  25   d  and the fourth side surface  25   e.    
     Next, a manufacturing process of the laminated inductor component of the present embodiment will be described with reference to  FIGS.  2 A to  2 Q . 
     As illustrated in  FIG.  2 A , by repeating a process in which an insulating paste containing borosilicate glass as the main ingredient is applied onto a carrier film (not illustrated) by screen printing, an insulator layer  17   a  for an outer layer having an appropriate thickness is formed. 
     Next, as illustrated in  FIG.  2 B , a photosensitive insulating paste is applied onto the insulator layer  17   a  for the outer layer by screen printing, and an insulating paste layer  18   a  including an opening  18  is formed by a photolithography process. The opening  18  is a portion where the insulating paste layer  18   a  is removed and the insulator layer  17   a  for the outer layer is exposed, and the portion other than the opening  18  is a portion where the insulating paste layer  18   a  remains. A step g is formed at an end portion of the opening  18 . 
     Next, as illustrated in  FIG.  2 C , by the application of the photosensitive insulating paste and the photolithography process, a bank portion  18   b  is formed by laminating an insulating paste layer at only one side of the opening  18  in a predetermined range, and a groove  19   a  is formed between the bank portion  18   b  and the step g. 
     Note that the bank portion  18   b  may be formed by removing part of the insulating paste layer  18   a  without depending on only the lamination of the insulating paste layer. As for the shape of the groove  19   a , a step on the bank portion  18   b  side is formed to be high relative to the opening  18 , and the bank portion  18   b  is a base portion at a time when the insulator layer  24  is laminated. 
     Next, as illustrated in  FIG.  2 D , the groove  19   a  is filled with the photosensitive conductive paste layer to be the outermost layer  23   a  of the coil conductor layer  23  and the first and second outer conductors  13   a  and  13   b , by the screen printing and the photolithography process. 
     Next, as illustrated in  FIG.  2 E , an insulating paste layer  18   c  including the via  14  is formed, and as illustrated in  FIG.  2 F , a groove  19   b  for forming the coil conductor layer  23  and the first and second outer conductors  13   a  and  13   b  is formed. 
     Thus, as illustrated in  FIGS.  2 G to  2 N , by laminating the insulating paste layer and the conductive paste layer in sequence, the insulating paste layer  18   a  to an insulating paste layer  18   f , the coil conductor layer  23 , and the first and second outer conductors  13   a  and  13   b  are laminated. 
     Then, as illustrated in  FIGS.  2 N to  2 P , the outermost layer  23   b  of the coil conductor layer  23  is so formed as to include the step g, and as illustrated in  FIG.  2 Q , an insulator layer  17   b  for an outer layer is further formed, whereby the outermost layer  24   b  of the insulator layer  24  is formed along the step g. 
     The lamination process illustrated in  FIGS.  2 A to  2 Q  is described for one laminated inductor component. However, in practice, a large number of laminated inductor components may be manufactured as a mother multilayer body in which the stated laminated inductor components are arranged in matrix form. 
     In this case, the mother multilayer body is cut with a dicing machine into individual multilayer bodies  11  each including a single coil conductor  12 , and thereafter the individual multilayer bodies  11  are fired. Then, after barrel finishing is performed on the multilayer body  11 , by the outer conductors  13   a  and  13   b  of the multilayer body  11  being plated with the metal layer  16 , the laminated inductor component including the coil conductor  12  is formed inside the multilayer body  11 . 
       FIG.  3    shows a change in a Q factor with respect to an input signal of about 1 GHz, when the thickness t 2  of each of the outermost layers  24   a  and  24   b  of the insulator layer  24  and the line width of the coil conductor layer  23  are changed in the laminated inductor component constituted as described above. In this figure, a characteristics line A shows a case where the thickness t 2  of each of the outermost layers  24   a  and  24   b  is about 6 μm and the line width of the coil conductor layer  23  is about 15 μm, a characteristics line B shows a case where the thickness t 2  is about 16 μm and the line width of the coil conductor layer  23  is about 20 μm, and a characteristics line C shows a case where the thickness t 2  is about 28 μm and the line width of the coil conductor layer  23  is about 25 μm. 
     As shown in  FIG.  3   , when the thickness t 2  is reduced, it is possible to increase the aspect ratio of the coil conductor  12  within a limited outer shape size of the multilayer body  11  and to improve the Q factor. 
     Next, action of the laminated inductor component of the present embodiment constituted as described above will be described. 
     In the laminated inductor component of the present embodiment, the thickness t 1  of the coil conductor layer  23  is increased, so that the resistance of the coil conductor  12  is reduced. In particular, since a high-frequency signal flowing through the coil conductor  12  mainly passes through an inner diameter side surface of the coil conductor  12 , when the thickness t 1  of the coil conductor layer  23  increases, alternating current resistance (Rac) decreases. Therefore, the Q factor of the laminated inductor component is improved. 
     Here, as the thickness t 1  of the coil conductor layer  23  increases, the coil length d 2  increases; however, the width d 1  of each of the outer conductors  13   a  and  13   b  is shorter than the coil length d 2 . Therefore, the metal layer  16 , with which the surfaces of the outer conductors  13   a  and  13   b  are plated, does not extend onto the third side surface  25   d  and the fourth side surface  25   e  of the multilayer body  11 . As a result, generation of a variation in the outer diameter dimension of the laminated inductor component is suppressed. Further, since the metal layer  16  does not extend onto the third side surface  25   d  and the fourth side surface  25   e  of the multilayer body  11 , a range in which the passage of magnetic flux is prevented is reduced, and efficiency in obtaining inductance in the laminated inductor component is improved. 
     Note that the first and second outer conductors  13   a  and  13   b  are formed being laminated through the same process as the lamination process of the coil conductor layer  23  and the outermost layers  23   a  and  23   b  thereof. Therefore, dimensional accuracy of positioning of the first and second outer conductors  13   a  and  13   b  in the lamination direction is improved with respect to the coil conductor layer  23  and the outermost layers  23   a  and  23   b  thereof. Accordingly, dimensional accuracy of the width d 1  of each of the first and second outer conductors  13   a  and  13   b  as well as the step g is improved. 
     With the laminated inductor component constituted as described above, the following effects can be obtained. 
     (1) Since the width d 1  of each of the first and second outer conductors  13   a  and  13   b  is made shorter than the coil length d 2  of the coil conductor  12 , it is possible to prevent the metal layer  16 , with which the first and second outer conductors  13   a  and  13   b  are plated, from extending onto the third side surface  25   d  and the fourth side surface  25   e . Accordingly, it is possible to suppress the variation in the outer diameter dimension of the multilayer body  11  incorporating the inductor formed of the coil conductor  12 , and to smoothly mount the multilayer body  11  to the mounting position by the mounting device in the mounting process, and to prevent the occurrence of short circuit with an adjacently mounted component. 
     (2) By making the distances d 3  between both the end portions in the lamination direction of the first and second outer conductors  13   a ,  13   b  and the third and fourth side surfaces  25   d ,  25   e  be greater than the thicknesses t 2  of the outermost layers  24   a  and  24   b  of the insulator layer  24 , it is possible to increase the aspect ratio of the coil conductor layer  23  without increasing the outer shape of the multilayer body  11 . Accordingly, it is possible to reduce the resistance of the coil conductor  12  and to improve the Q factor of the inductor formed of the coil conductor  12 . 
     (3) Since it is possible to prevent the metal layer  16 , with which the first and second outer conductors  13   a  and  13   b  are plated, from extending onto the third side surface  25   d  and the fourth side surface  25   e , efficiency in obtaining the inductance can be enhanced. 
     (4) Since the first and second outer conductors  13   a  and  13   b  can be formed being laminated through the same process as the lamination process of the coil conductor  12 , the positional accuracy of each of the first and second outer conductors  13   a  and  13   b  with respect to the coil conductor  12  can be enhanced. Further, in comparison with a case where the first and second outer conductors  13   a  and  13   b  are formed in different processes, the number of processes can be decreased. 
     The above embodiment may be modified as follows. 
     As illustrated in  FIG.  4 A , the steps g may be formed not at the connection portions between the first and second outer conductors  13   a ,  13   b  and the extended electrodes  15   a ,  15   b , but at the connection portions between the outermost layers  23   a ,  23   b  of the coil conductor layer  23  and the extended electrodes  15   a ,  15   b . Like in the above-described embodiment, these steps g can be formed in the process illustrated in  FIG.  6 A . In this case, by forming the steps g, the thickness in the lamination direction of each of the extended electrodes  15   a  and  15   b  is thinner than the thickness of each of the outermost layers  23   a  and  23   b  of the coil conductor layer  23 . 
     As such, as illustrated in  FIG.  5   , it is preferable that a line width w 2  of each of the extended electrodes  15   a  and  15   b  be formed wider than a line width w 1  of the coil conductor layer  23 , and that the cross-sectional area of each of the extended electrodes  15   a  and  15   b  be formed equal to or larger than that of the outermost layers  23   a  and  23   b  of the coil conductor layer  23  respectively. Thus, an increase in resistance at each of the portions of the extended electrodes  15   a  and  15   b  can be suppressed. 
     As illustrated in  FIG.  4 B , at the connection portions between the extended electrodes  15   a ,  15   b  and the first and second outer conductors  13   a ,  13   b , by forming slopes  21 , as the steps, at end portions in a longitudinal direction of the first and second outer conductors  13   a  and  13   b , the width of each of the first and second outer conductors  13   a  and  13   b  along the lamination direction may be configured to be shorter than the coil length. 
     As illustrated in  FIG.  4 C , at the connection portions between the extended electrodes  15   a ,  15   b  and the first and second outer conductors  13   a ,  13   b , by forming slopes  22 , as the steps, on the extended electrodes  15   a  and  15   b , the width of each of the outer conductors  13   a  and  13   b  along the lamination direction may be configured to be shorter than the coil length. 
     The slopes  21  and  22  illustrated in  FIGS.  4 B and  4 C  can be formed in the process illustrated in  FIG.  2 B , for example, by changing the thickness of the insulating paste  18   a  to be applied at an end portion of the groove  19   a , as illustrated in  FIG.  6 B , by a pattern printing method with a screen mask where used is the screen mask in which only a portion for forming the step is open. Alternatively, at the end portion of the groove  19   a , the above-mentioned slope may be formed by increasing the number of times of application. According to these methods, the step is formed at the end portion of the groove  19   a , and the insulating paste flows from a thicker application-thickness portion toward a thinner application-thickness portion of the insulating paste layer  18   a  to form the slope. 
     The step g and the slopes  21 ,  22  as illustrated in  FIGS.  4 A to  4 C  may be formed by half-etching while adjusting an exposure amount, a development time, and an amount of etching in a photolithography process. 
     The manufacturing process of the laminated inductor component of the present embodiment is merely an example, and other known methods may be used. For example, the layer may be formed by spin coating or spray coating, or may be patterned by laser processing or drilling. Further, a sheet lamination method, a printing lamination method, or the like may be used. 
     The metal layer is not limited to a layer formed by plating, and may be a resin electrode or a metal layer formed by sputtering. 
     In the embodiment, although the width d 1  is made shorter than the coil length d 2  by the lamination process, the width d 1  of each of the first outer conductor  13   a  and the second outer conductor  13   b  may be formed to be shorter than the coil length d 2  by, for example, a pressing process in the sheet lamination method. 
     The multilayer body  11  may have a mounting area of “0201”, i.e., about 0.2 mm×about 0.1 mm, or “0402”, “0603”, “1005” or the like. The above-discussed embodiment is particularly useful in a case of forming a multilayer body having a size of equal to or smaller than “0402”. 
     While some embodiments of the disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure. The scope of the disclosure, therefore, is to be determined solely by the following claims.