Abstract:
A resistor, including a resistive element made of a metal plate, has a low resistance resulting from connection terminal electrodes formed on both ends of the lower surface of the resistive element. The object thereof is to achieve weight reduction by reducing the height and also to achieve lower costs. To attain the above object, the ends of the lower surface of the resistive element are provided with recesses for accommodating the connection terminal electrodes, while at least the intermediate area of the lower surface of the resistive element between the connection terminal electrodes is covered with an insulator. Alternatively, a recess may be formed in the middle of the lower surface of the resistive element for using the ends of the lower surface as a pair of connection terminal electrodes, the recess being internally covered with an insulator.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a chip resistor having a low resistance of, for example, no more than 1 Ω, and to a method of making the same.  
         [0002]     As a prior art document, JP-A-2001-118701 proposes a chip resistor  1  constructed as shown in  FIG. 1 .  
         [0003]     Specifically, the resistor element  2  of a chip resistor  1  of the prior art is formed in rectangular shape of metal plate of thickness T 0 , length L and width W, and made of a material such as an alloy constituted by adding metal having higher resistance such as nickel to a substrate metal having a low resistance such as copper. Connection terminal electrodes  4 ,  5  are provided in portions at the left and right ends of the lower surface of this resistor element  2 , by using cutting processing to cut a recess  3  of length L 0  and depth S in about the middle of the lower surface of this resistor element  2 . In addition, plating layers  6 ,  7  are formed on these two connection terminal electrodes  4  and  5  in order to facilitate soldering to a printed circuit board, for example.  
         [0004]     Also, in JP-A-2001-118701, when manufacturing a chip resistor constructed as described above, a method of manufacturing is proposed wherein plating layers  6 ,  7  for soldering are formed in a portion of each of the connection terminal electrodes  4  and  5  by plating processing in a condition with a resist mask for partial plating applied to the lower surface of the metal plate blank, the blank being formed by a large number of resistors arranged side by side in integrated fashion, and after cutting the recess  3  in the lower surface of the metal plate blank by cutting processing, the metal plate blank is then cut into each of the resistor elements.  
         [0005]     However, with the chip resistor  1  of the prior art, there is a considerable risk that, when soldering onto the printed circuit board or the like, molten solder will become attached to portions between the two connection terminal electrodes  4 ,  5  on the resistor element  2  beyond the two connection terminal electrodes  4 ,  5 , thereby producing a change in the resistance. In order to avoid this, the depth S in the recess  3  of the lower surface of the resistor element  2  may be made greater, but, if an attempt is made to increase the depth S in the recess  3  without changing the thickness T of the resistor element between the connection terminal electrodes, the overall height of the chip resistor  1  is increased and the weight is increased.  
         [0006]     Also, in the method of manufacture of the prior art, it is arranged to form plating layers  6 ,  7  for soldering solely on the portions of the connection terminal electrodes  4 ,  5  by performing plating treatment in a condition with a resist mask for partial plating applied to the lower surface of the metal plate blank. In this manner, the manufacturing costs can be greatly increased due to the need for a step of forming a resist mask for partial plating beforehand on the lower surface of the metal plate blank prior to the plating step of forming the plating layers  6 ,  7  for the soldering, and also a step of separating and removing the resist mask for the partial plating after the plating step.  
       DISCLOSURE OF THE INVENTION  
       [0007]     The object of the present invention is to eliminate these problems.  
         [0008]     In order to attain this object, according to a first aspect of the present invention, there is provided a chip resistor having a low resistance. In claim  1 , a recess is provided in a portion at each of the left and right ends in the lower surface of a resistor element composed of a metal plate. The recesses each are provided with connection terminal electrodes made of metal of lower resistance than the resistor element. At least a portion between the two connection terminal electrodes in the lower surface of the resistor element is covered with an insulator.  
         [0009]     In claim  2 , the surfaces of the respective connection terminal electrodes are made substantially flush with a surface of the insulator or projects from the surface of the insulator.  
         [0010]     In claim  3 , the connection terminal electrodes comprise a metal plating layer.  
         [0011]     Regarding a method of making the chip resistor having a low resistance according to the first aspect of the present invention, in claim  5 , it comprises a step of preparing a metal plate blank formed by a large number of resistor elements, each constituting a single chip resistor, arranged side by side in integrated fashion, a step of covering at least the lower surface of the metal plate blank with an insulator, a step of cutting concave grooves in portions of the left and right ends in the resistor elements in the lower surface in the metal plate blank while removing portions in the insulator corresponding to the portions of the left and right ends in the resistor elements, a step of forming a metal plating layer constituting connection terminal electrodes made of metal of lower resistance than the metal plate blank, the plating layer being in the concave grooves in the lower surface in the metal plate blank, and a step of dividing the metal plate blank into individual resistor elements.  
         [0012]     In this way, by covering with an insulator at least the portion between the two connection terminal electrodes in the lower surface of the resistor elements comprised by the metal plate, it is possible to use this insulator to prevent contact of molten solder with the portion between the two connection terminal electrodes in the resistor element when soldering onto a printed circuit board or the like. Consequently, since it is unnecessary to increase the height of the connection terminal electrodes in order to avoid contact of the molten solder, the overall height in the chip resistor can be made correspondingly lower and a reduction in weight thereby achieved.  
         [0013]     Also, in the prior art construction shown in  FIG. 1 , the resistance between the two connection terminal electrodes i.e. the resistance in the chip resistor, in addition to the resistivity in the metal constituting the resistor element  2  and the width W 0  in the resistor element  2  is determined by the length L 0  in the portion of the recess  3  that is cut in the lower surface in the resistor element  2  and the remaining thickness T after cutting of the recess  3  of depth S. Manufacturing variability of the length L 0  and depth S in the recess  3  that is cut into the lower surface in the resistor element  2  therefore appears as variability of the resistance in the chip resistor  1 . However, with the features of claim  1 , since a recess is provided in a portion at both the left and right ends in the lower surface of the resistor element and connection terminal electrodes made of metal of lower resistance than the resistor element are provided within this recess, the depth of the recess that is cut in the lower surface in the resistor element has no influence or only a small influence on the resistance between the two connection terminals i.e. the resistance in the chip resistor. Consequently, when cutting the recess, the accuracy of processing the depth need not be high, and high processing accuracy need only be maintained in respect of the length. The processing required in cutting the recess in the resistor element can therefore be reduced, making it possible to reduce the manufacturing cost.  
         [0014]     Also, by arranging that, as in claim  2 , when the portion between the two connection terminal electrodes is covered with an insulator the surface of the two connection terminal electrodes is made substantially flush with the surface of the insulator or projects from the surface of the insulator, the advantage is obtained that the reliability and strength of the soldering when soldering onto a printed circuit board or the like are improved since the amount by which the two connection terminal electrodes project above the printed circuit board can be made small or eliminated.  
         [0015]     Also, as in claim  3 , by forming the two connection terminal electrodes as a metal plating layer, the height in the chip resistor can be further reduced and its weight further decreased.  
         [0016]     Also, with a manufacturing method as in claim  5 , a large number of chip resistors constructed as above can be produced from a single metal plate blank and, in addition, when forming a metal plating layer to provide the connection terminal electrodes in the recess, the insulator that is formed on the lower surface of the metal plate blank provides a mask whereby this metal plating layer is formed only in the recess. In other words, the insulator may be used to ensure that the metal plating layer is formed only in the recess, without needing to perform masking of the lower surface of the metal plate blank. This therefore simplifies the plating step and makes it possible to achieve a considerable reduction in manufacturing costs.  
         [0017]     According to a second aspect of the present invention, there is provided a chip resistor having a low resistance. In claim  4 , a recess is provided in about the middle of the lower surface in a resistor element composed of a metal plate, so that the lower surface of the resistor element has two end portions used as a pair of connection terminal electrodes, the connection terminal electrodes being formed with a plating layer, and the interior of the recess is covered with an insulator.  
         [0018]     Regarding a method of making the chip resistor having a low resistance according to the second aspect of the present invention, in claim  6 , it comprises a step of preparing a metal plate blank formed by a large number of resistor elements, each constituting a single chip resistor, arranged side by side in integrated fashion, a step of cutting concave grooves constituting recesses in about the middle of the resistor elements in the lower surface of the metal plate blank, a step of covering the interior of the concave grooves in the lower surface of the metal plate blank with an insulator, a step of forming a plating layer on the lower surface of the metal plate blank and a step of dividing the metal plate blank into individual resistor elements.  
         [0019]     In claim  7 , it comprises a step of preparing a metal plate blank formed by a large number of resistor elements, each constituting a single chip resistor, arranged side by side in integrated fashion, a step of cutting concave grooves constituting recesses in about the middle of the resistor elements of the lower surface of the metal plate blank, a step of covering the upper surface of the metal plate blank and the interior of the concave grooves in the lower surface of the metal plate blank with an insulator, a step of forming a plating layer on the lower surface of the metal plate blank and a step of dividing the metal plate blank into individual resistor elements.  
         [0020]     In this way, by covering the interior of the recess in the lower surface of the resistor element with an insulator, adhesion of molten solder to the portion of the resistor element between the two connection terminal electrodes when soldering onto the printed circuit board or the like can be prevented by this insulator. There is therefore no need to increase the height of the connection terminal electrodes in order to avoid the aforementioned adhesion, so the overall height in the chip resistor can be correspondingly reduced and a reduction in weight thereby achieved.  
         [0021]     Furthermore, in the manufacturing method in this case, as described in claim  6  and claim  7 , plating processing for forming a plating layer for soldering on each of the connection terminal electrodes may be performed after cutting the recesses in the metal plate blank and covering the interior of these recesses with an insulator. The insulator used to cover the interior of these recesses prior to the plating step therefore functions as a mask for partial plating for forming a plating layer for soldering only at the connection terminal electrodes. The step of forming a resist mask for partial plating beforehand prior to the plating step and the step of separating and removing the resist mask for partial plating after the plating step as in the prior art can therefore be dispensed with, so the manufacturing steps can be correspondingly simplified, enabling the cost of manufacturing a chip resistor having the beneficial effects described above to be greatly reduced.  
         [0022]     In particular, as described in claim  7 , by covering the upper surface of the metal plate blank with an insulator, in the plating step of forming a plating layer for soldering on the lower surface of the metal plate blank, the formation of a plating layer on the upper surface on the blank substrate can be prevented by the insulator that covers this upper surface. In other words, the insulator that covers the upper surface of the resistor element in the chip resistor can be utilized as a mask formed beforehand on this upper surface for preventing formation of a plating layer on this upper surface in the plating step. Thus, the advantages are obtained that the plating step is simplified and manufacturing costs can be further reduced. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]      FIG. 1  is a perspective view showing a chip resistor according to the prior art;  
         [0024]      FIG. 2  is a perspective view showing a chip resistor according to a first embodiment of the present invention;  
         [0025]      FIG. 3  is a cross-sectional view seen along the line III-III of  FIG. 2 ;  
         [0026]      FIG. 4  is a bottom view of  FIG. 2 ;  
         [0027]      FIG. 5  is a cross-sectional view seen along the line V-V of  FIG. 2 ;  
         [0028]      FIG. 6  is a cross-sectional view seen along the line VI-VI of  FIG. 2 ;  
         [0029]      FIG. 7  is a perspective view showing a first step in a method of manufacturing a chip resistor;  
         [0030]      FIG. 8  is a perspective view showing a second step in the method of manufacture;  
         [0031]      FIG. 9  is a perspective view showing a third step in the method of manufacture;  
         [0032]      FIG. 10  is a cross-sectional view to a larger scale seen along the line X-X of  FIG. 9 ;  
         [0033]      FIG. 11  is a perspective view showing a fourth step in the method of manufacture;  
         [0034]      FIG. 12  is a cross-sectional view to a larger scale seen along the line XII-XII of  FIG. 11 ;  
         [0035]      FIG. 13  is a cross-sectional view showing a first step in a further method of manufacture;  
         [0036]      FIG. 14  is a cross-sectional view showing a second step in a further method of manufacture;  
         [0037]      FIG. 15  is a cross-sectional view of a chip resistor according to a further method of manufacture;  
         [0038]      FIG. 16  is a perspective view showing a chip resistor according to a second embodiment of the present invention;  
         [0039]      FIG. 17  is a cross-sectional view seen along the line XVII-XVII of  FIG. 16 ;  
         [0040]      FIG. 18  is a bottom view of  FIG. 16 ;  
         [0041]      FIG. 19  is a perspective view showing a first step in a method of manufacturing a chip resistor;  
         [0042]      FIG. 20  is a perspective view showing a second step in the method of manufacture;  
         [0043]      FIG. 21  is a cross-sectional view to a larger scale shown along the line XXI-XXI of  FIG. 20 ;  
         [0044]      FIG. 22  is a perspective view showing a third step in the method of manufacture;  
         [0045]      FIG. 23  is a cross-sectional view to a larger scale shown along the line XXIII-XXIII of  FIG. 22 ;  
         [0046]      FIG. 24  is a perspective view showing a fourth step in the method of manufacture; and  
         [0047]      FIG. 25  is a cross-sectional view to a larger scale shown along the line XXIV-XXIV of  FIG. 24 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0048]     A first embodiment of the present invention is described below with reference to  FIG. 2  to  FIG. 6 . In these Figures, the reference symbol  11  indicates a chip resistor according to an embodiment of the present invention.  
         [0049]     This chip resistor  11  comprises a resistor element  12  formed in rectangular shape of length L and width W.  
         [0050]     This resistor element  12  is made of metal plate of thickness T. The metal used is for example alloy such as copper-nickel alloy, nickel-chromium alloy or iron-chromium alloy in which metal (hereinafter called a high-resistant metal) having a higher resistance than a metal substrate is added to the substrate, which is made of a metal having a lower resistance (hereinafter called low-resistant metal).  
         [0051]     In portions at the two ends of the lower surface of  12   b , of the upper and lower surfaces  12   a  and  12   b  of the resistor element  12 , recesses  13  and  14  are cut which are respectively of length L 1 , L 2  from the two end faces  12   c ,  12   d  of this resistor element  12 , and of depth S.  
         [0052]     Also, both the upper surface  12   a  and the lower surface  12   b  of the resistor element  12  are covered with insulators  15 ,  16  made of for example heat-resistant synthetic resin or glass.  
         [0053]     In addition, connection terminal electrodes  17 ,  18  made of pure metal such as copper are formed as a metal plating layer within the recesses  13 ,  14  in the portions at the two ends of the lower surface  12   b  of the resistor element  12 .  
         [0054]     The thickness of these two connection terminal electrodes  17 ,  18  is set to a dimension such that the surfaces thereof lie substantially in the same plane as the surface of the insulator  16  on the lower surface  12   b  of the resistor element  12 , or projects slightly from the surface.  
         [0055]     Also, plating layers  19 ,  20  made of tin or solder or the like are formed on the surface of the two connection terminal electrodes  17 ,  18  in order to facilitate soldering onto the printed circuit board or the like.  
         [0056]     Yet further, if required, the resistance of this chip resistor  11  is adjusted to a prescribed value by cutting a trimming groove  21  shown by the double-dotted chain line in  FIG. 4  in a side face of the chip resistor  11 .  
         [0057]     In the chip resistor  11  constructed in this way, molten solder can be reliably prevented from contacting the portion between the two connection terminal electrodes  17 ,  18  of the resistor element  12  when soldering the chip resistor  11  onto a printed circuit board or the like, by means of the insulator  16  covering the lower surface  12   b  of the resistor element  12 .  
         [0058]     Also, in the above construction, the resistance between the two connection terminal electrodes  17 ,  18  i.e. the resistance of this chip resistor  11  is determined by the resistivity of the metal constituting the resistor element  12 , the width W of the resistor element  12  and the length L 3  (L 3 =L−L 1 +L 2 ) between the two connection terminal electrodes  17 ,  18  of the resistor  12 . The effect that the depth S of the two recesses  13 ,  14  has on the resistance in the chip resistor  11  in the prior art can therefore be eliminated or decreased.  
         [0059]     A chip resistor  11  constructed in this way can be manufactured by the following steps (1) to (7) described below.  
         [0060]     (1) As shown in  FIG. 7 , a metal plate blank A is prepared, which is formed by a large number of resistor elements  12  constituting a single chip resistor  11  as arranged side by side in integrated fashion. Reference symbol B 1  and reference symbol B 2  indicate longitudinal cutting lines and transverse cutting lines that demarcate the metal plate blank A into each of the resistor elements  12 .  
         [0061]     (2) Both the upper surface A 1  and the lower surface A 2  of the metal plate blank A are covered with insulators  15 ,  16  of for example heat-resistant synthetic resin or glass, as shown in  FIG. 8 .  
         [0062]     (3) Concave grooves A 3  for forming recesses  13 ,  14  in the portions at the two ends of the resistor elements  12  are then cut, as shown in  FIG. 9  and  FIG. 10 , in the lower surface A 2  of the metal plate blank A by mechanical processing such as cutting or grinding or processing using irradiation with a laser beam or coining processing or the like. In this process, the portions of the insulator  16  corresponding in position to the two recesses  13 ,  14  in the lower surface A 2  is also removed.  
         [0063]     The depth in the concave groove A 3  which is thus cut is S (see  FIG. 2 ) and the width L 4  in this concave grooves A 3  is L 4 =L 1 +L 2 +α (where L 1  and L 2  are the lengths of the two recesses  13  and  14 ). When using a dicing pattern or the like to cut the metal plate blank A along the cutting lines B 1  in the longitudinal direction so as to divide the metal plate blank A into the individual resistor elements  12 , the value of a noted above is set to the cutting width of e.g. a dicing cutter, that is, the cutting allowance. It should be noted that in the case where this division is effected by shearing processing, α is taken as =0 and the width L 4  is set at L 4 =L 1 +L 2 . In this way, the dimension between mutually adjacent concave grooves A 3  becomes the length L 3  between the two recesses  13 ,  14  (the two connection terminal electrodes  17 ,  18 ) in the chip resistors  11 , i.e. the length L 3  at which the prescribed resistance is obtained.  
         [0064]     (4) After cutting the concave grooves A 3 , the metal plating layer A 4  is formed in the portion within the concave grooves A 3  as shown in  FIG. 11  and  FIG. 12  by performing plating processing in respect of the entire metal plate blank A. In this way, this metal plating layer A 4  provides the connection terminal electrodes  17 ,  18 .  
         [0065]     (5) As shown in  FIG. 11  and  FIG. 12 , a plating layer A 5  is formed on the upper surface of the metal plating layer A 4  by further plating processing in respect of the entire metal plate blank A, after formation of the metal plating layer A 4 , and this plating layer A 5  is employed for the plating layers  19 ,  20  for soldering.  
         [0066]     (6) This metal plate blank A is then divided into the individual resistor elements  12  by cutting along the longitudinal cutting lines B 1  and transverse cutting lines B 2  using for example a dicing cutter. Also, this division could be performed using shearing processing instead of cutting using a dicing cutter or the like.  
         [0067]     (7) If required, the resistance between the two connection terminal electrodes  17 ,  18  is adjusted to the prescribed value by cutting a trimming groove  21  using for example laser light irradiation onto a side face whilst measuring the resistance between the two connection terminal electrodes  17 ,  18 .  
         [0068]     By going through these steps, a large number of chip resistors  11  of the construction shown in  FIG. 2  to  FIG. 6  can be manufactured from a single metal plate blank A.  
         [0069]     In this manufacture, the insulators  15 ,  16  that cover the upper and lower surfaces A 1 , A 2  of the metal plate blank A provide masks when forming the connection terminal electrodes  17 ,  18  only on the portion within the concave grooves A 3  by plating processing and when forming the plating layers  19 ,  20  for soldering purposes by plating processing only of the surface of these connection terminal electrodes  17 ,  18 .  
         [0070]     Next,  FIG. 13  and  FIG. 14  show a manufacturing method according to an embodiment of the present invention.  
         [0071]     In the method, as shown in  FIG. 13 , the concave groove A 3  mentioned above comprises a concave groove A 3 ′ for forming a single recess  13 ′ in the resistor element  12  and a concave groove A 3 ″ for forming the other recess  14 ′, and the dimension between these two adjacent concave grooves A 3 ′, A 3 ″ (i.e. the dimension between the adjacent concave grooves A 3 ′, A 3 ″ on the side where the cutting line B 1  is not located) constitutes the length L 3  whereby the prescribed resistance is obtained.  
         [0072]     Thus, as shown in  FIG. 14 , within the concave grooves A 3 ′, A 3 ″, metal plating layers A 4 ′, A 4 ″ are formed by plating processing and these metal plating layers A 4 ′, A 4 ″ are employed as the connection terminal electrodes  17 ′,  18 ′. Apart from this, this method is the same as in the case of the method (1) to (7) described above and makes it possible to obtain chip resistors  11 ′ of the construction shown in  FIG. 15 .  
         [0073]     In other words, “recesses are provided in a portion at the left and right ends on the lower surface of the resistor element” in the first embodiment of the present invention means that there are included both the case where, as shown in  FIG. 3 , the two recesses  13 ,  14  are in contact with the two end surfaces  12   c ,  12   d  of the resistor element  12  and the case where, as shown  FIG. 15 , the two recesses  13 ′,  14 ′ that form the respective connection terminal electrodes  17 ′,  18 ′ are close to but do not contact the two end surfaces  12   c ′,  12   d ′ of the resistor element  12 ′.  
         [0074]     Next, a second embodiment of the present invention will be described with reference to  FIG. 16  to  FIG. 20 .  
         [0075]     In these Figures, the reference symbol  111  indicates a chip resistor according to the second embodiment of the present invention.  
         [0076]     This chip resistor  111  comprises a resistor element  112  that is formed in a rectangular shape with a length L and a width W.  
         [0077]     This resistor element  112  is made of metal plate of thickness T. The metal used is for example alloy such as copper-nickel alloy, nickel-chromium alloy or iron-chromium alloy in which metal (hereinafter called a high-resistant metal) having a higher resistance than a substrate is added to the substrate, which is made of a metal having a lower resistance (hereinafter called low-resistant metal).  
         [0078]     Connection terminal electrodes  117 ,  118  are formed at portions at the two ends thereof by cutting a recess  113  of length L 0  and depth S in the lower surface of the upper and lower surfaces of the resistor element  112 , in about the middle thereof.  
         [0079]     In order to facilitate soldering onto a printed circuit board or the like, plating layers  119 ,  120  comprising for example an underlayer of copper plating onto which tin plating is applied are formed on these two connection terminal electrodes  117 ,  118 .  
         [0080]     Also, in addition to covering the upper surface of the resistor element  112  with an insulator  115  made of for example heat-resistant synthetic resin or glass, the interior of the recess  13  in the lower surface is covered with an insulator  116  made of for example heat-resistant synthetic resin or glass.  
         [0081]     It should be noted that, if required, the resistance of this chip resistor  111  may be adjusted to a prescribed value by cutting a trimming groove  121  shown by the double-dotted chain line in  FIG. 18  in a side face of the chip resistor  111 .  
         [0082]     In the chip resistor  111  constructed in this way, molten solder can be reliably prevented from contacting the portion between the two connection terminal electrodes  117 ,  118  of the resistor element  112  when soldering the chip resistor  111  onto a printed circuit board or the like, by means of the insulator  116  covering the recess  113  of the lower surface of the resistor element  112 .  
         [0083]     A chip resistor  111  constructed in this way can be manufactured by the steps (1) to (6) described below.  
         [0084]     (1) As shown in  FIG. 19 , a metal plate blank C is prepared, which is formed by a large number of resistor elements  112  constituting a single chip resistor  111  as arranged side by side in integrated fashion. Reference symbol D 1  and reference symbol D 2  indicate longitudinal cutting lines and transverse cutting lines that demarcate the metal plate blank C into each of the resistor elements  112 .  
         [0085]     (2) The lower surface C 2 , of the upper surface C 1  and lower surface C 2  of the metal plate blank C, is turned upwards and the recess  113  is made as shown in  FIG. 20  and  FIG. 21  by for example mechanical processing such as cutting or grinding or processing using irradiation with laser light, or coining processing, such that the recess  113  extends parallel with the longitudinal cutting line D 1  in the portion in about the middle of the resistor elements  112  of the lower surface C 2 .  
         [0086]     The depth of the recess  113  that is thus cut is S and the width of this recess  113  is L 0  (see  FIG. 16 ).  
         [0087]     (3) Then, in addition to covering the surface of the metal plate blank C with an insulator  18  such as heat-resistant synthetic resin or glass as shown in  FIG. 22  and  FIG. 23 , the interior of the recesses  113  of the lower surface C 2  is covered with an insulator  116  such as heat-resistant synthetic resin or glass.  
         [0088]     (4) Next, as shown in  FIG. 24  and  FIG. 25 , by performing plating processing of the metal plate blank C in a plating solution, plating layers  119 ,  120  are formed in the portions of the lower surface C 2  of this metal plate blank C excluding those of the insulator  116  that covers the interior of the recess  113  i.e. in the portions of the connection terminal electrodes  117 ,  118  of the resistor elements  112 .  
         [0089]     (5) The metal plate blank C is then divided into the resistor elements  112  by cutting along the longitudinal cutting lines D 1  and the transverse cutting lines D 2  with the use of a dicing cutter, for example. The cutting of the metal plate blank C into the resistor elements  112  can also be performed using shearing processing.  
         [0090]     (6) If required, the resistance between the two connection terminal electrodes  117 ,  118  is then adjusted to the prescribed value by cutting a trimming groove  121  using for example laser light irradiation onto a side face whilst measuring the resistance between the two connection terminal electrodes  117 ,  118 .  
         [0091]     By going through these steps, a large number of chip resistors  111  of the construction shown in  FIG. 16  to  FIG. 18  can be manufactured from a single metal plate blank C.  
         [0092]     In this manufacture, the insulators  115 ,  116  that cover the upper and lower surfaces C 1 , C 2  of the metal plate blank C function as masks for plating when the plating layers  119 ,  120  are formed by plating processing only of the portions of the connection terminal electrodes  117 ,  118  of the lower surface C 2  of the metal plate blank C.