Patent Publication Number: US-10332660-B2

Title: Resistor element

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefits under 35 USC 119 (a) of Korean Patent Application No. 10-2016-0156152, filed on Nov. 23, 2016 in the Korean Intellectual Property Office, the entire disclosure of which are incorporated herein by reference for all purposes. 
     BACKGROUND 
     1. Field 
     The following description relates to a resistor element. 
     2. Description of Related Art 
     A resistor element in a chip shape is suitable for implementing a precise resistor, and serves to adjust a current and to drop a voltage within an electronic circuit. 
     As electronic devices have recently been down-sized and refined, the size of the electronic circuits used in the electronic devices has gradually been miniaturized. Accordingly, the size of the resistor element has also gradually been miniaturized. In order to save costs and time related to the production of the resistor elements, various methods for reducing the number of manufacturing operations needed to produce the resistor elements have recently been proposed. 
     SUMMARY 
     An aspect of the present disclosure may provide a resistor element capable of reducing the number of manufacturing operations of the resistor element to efficiently produce the resistor element. 
     According to an aspect of the present disclosure, a resistor element may include a substrate having first and second surfaces facing each other, and a plurality of side surfaces connecting the first surface and the second surface with each other. A resistance layer is on at least one of the first and second surfaces. First and second terminals are connected to the resistance layer, and each include an upper electrode layer on the first surface, a lower electrode layer on the second surface, and a plurality of side electrode layers on at least a portion of the plurality of side surfaces. At least a portion of the side surfaces of the substrate is exposed between side electrode layers of the first terminal. 
     According to another aspect of the present disclosure, a resistor element may include a substrate having first and second surfaces facing each other, and a plurality of side surfaces connecting the first surface and the second surface with each other. First and second terminals each include an upper electrode layer on the first surface, a lower electrode layer on the second surface, and side electrode layers only on first side surfaces having a curved shape, among the plurality of side surfaces, to electrically connect the first electrode layer and the second electrode layer with each other. A resistance layer is on at least one of the first and second surfaces so as to be connected to the first terminal and the second terminal. There are no electrode layers on first side surfaces that do not have a curved shape, of the plurality of side surfaces. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating a resistor element according to an exemplary embodiment; 
         FIG. 2  is a perspective view illustrating a substrate included in the resistor element of the exemplary embodiment illustrated in  FIG. 1 ; 
         FIG. 3  is a plan view illustrating the resistor element of the exemplary embodiment illustrated in  FIG. 1 ; 
         FIG. 4  is a side view illustrating the resistor element of the exemplary embodiment illustrated in  FIG. 1 ; 
         FIG. 5  is a cross-sectional view illustrating a cross section taken along a direction I-I′ of the resistor element the exemplary embodiment illustrated in  FIG. 1 ; 
         FIG. 6  is a front view illustrating the resistor element of the exemplary embodiment illustrated in  FIG. 1 ; 
         FIG. 7  is a cross-sectional view illustrating a cross section taken along a direction II-II′ of the resistor element of the exemplary embodiment illustrated in  FIG. 1 ; 
         FIG. 8  is a perspective view illustrating a resistor element according to an exemplary embodiment; 
         FIG. 9  is a plan view illustrating the resistor element of the exemplary embodiment illustrated in  FIG. 8 ; 
         FIG. 10  is a front view illustrating the resistor element of the exemplary embodiment illustrated in  FIG. 8 ; 
         FIG. 11  is a perspective view illustrating a resistor element assembly including the resistor element according to the exemplary embodiment mounted on a circuit board; and 
         FIGS. 12 through 18  are views illustrating a method for manufacturing a resistor element according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments of the following description will now be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a perspective view illustrating a resistor element according to an exemplary embodiment.  FIG. 2  is a perspective view illustrating a substrate included in the resistor element of the exemplary embodiment illustrated in  FIG. 1 . 
     Referring to  FIG. 1 , a resistor element  100  may include a substrate  105 , a resistance layer  110 , and first and second terminals  120  and  130 . 
       FIG. 2  illustrates the substrate  105 . The substrate  105  may include a first surface  105 A, a second surface  105 B opposing each other, and a plurality of side surfaces  105 C,  105 D, and  105 E. The plurality of side surfaces  105 C,  105 D, and  105 E may include a first side  105 C having a curved shape, and second and third sides  105 D  105 E having planar shapes. In the exemplary embodiment illustrated in  FIG. 2 , the first side  105 C is illustrated as being curved inwardly into the substrate  105 , but is not necessarily limited thereto. There may be four first sides  105 C at the corners of the substrate  105 , two second sides  105 D on opposing sides of the substrate, and two third sides  105 E on opposing sides of the substrate. 
     The second and third sides  105 D and  105 E may each be disposed between first sides  105 C. That is, opposing ends of second sides  105 D may be connected to first sides  105 C, and opposing ends of third sides  105 E may also be connected to first sides  105 C. The first sides  105 C may each have a relatively smaller area than each of the second sides  105 D and each of the third sides  105 E. The second sides  105 D may each have a different area from each of the third sides  105 E. In the exemplary embodiment illustrated in  FIG. 2 , the area of each of the second sides  105 D are smaller than the area of each of the third sides  105 E. 
     The substrate  105  may have a plate shape having a predetermined thickness, and may include a material that may efficiently discharge heat generated by the resistance layer  110 . The substrate  105  may include a ceramic such as alumina (Al 2 O 3 ) or a polymer material. The substrate  105  may be an alumina substrate obtained by anodizing a surface of aluminum. 
     In the resistor element  100  according to an exemplary embodiment, the resistance layer  110  may be formed on at least one of the first surface  105 A and the second surface  105 B. Although  FIG. 1  illustrates the resistance layer  110  on the first surface  105 A, the resistance layer  110  may also be formed only on the second surface  105 B, or on both the first surface  105 A and the second surface  105 B. The resistance layer  110  may be electrically connected to a first terminal  120  and a second terminal  130  at opposing ends of the substrate  105  in a first direction (X axis direction). The resistance layer  110  may also have a region overlapping with the first terminal  120  and the second terminal  130  at opposing ends in the first direction. 
     The resistance layer  110  may include a metal, a metal alloy, or a metal oxide. As an example, the first resistance layer  110  may include at least one of a Cu—Ni based alloy, a Ni—Cu based alloy, a Ru oxide, a Si oxide, a Mn based alloy. The resistance layer  110  may be formed by coating and sintering a paste including the metal, the metal alloy, or the metal oxide onto the first surface  105 A or the second surface  105 B of the substrate  105  using a screen printing method, or the like. 
     The first terminal  120  and the second terminal  130  may be disposed to face each other in the first direction. The first terminal  120  and the second terminal  130  may be connected to the resistance layer  110 , and may be formed of a metal such as a nickel (Ni), silver (Ag), copper (Cu), platinum (Pt), tin (Sn), chromium (Cr), or the like. The first terminal  120  may include a first electrode layer  121  formed on the first surface  105 A, a second electrode layer  122  formed on the second surface  105 B, and side electrode layers  123 . 
     Referring to  FIGS. 1 and 2 , the second side surface  105 D may be exposed between the side electrode layers  123  included in the first terminal  120 . That is, the side electrode layers  123  included in the first terminal  120  may be formed only on first side surfaces  105 C. Accordingly, the second side surface  105 D may be exposed through the first terminal  120 . The first electrode layer  121  and the second electrode layer  122  may have the second side surface  105 D exposed therebetween, and may be electrically connected to each other by the side electrode layers  123 . This structure may be formed by a manufacturing operation of forming the first electrode layer  121  and the second electrode layer  122  together with the side electrode layers  123 , as described below. According to an exemplary embodiment, the first terminal  120  may be formed to outwardly protrude from the second side surface  105 D. 
       FIG. 3  is a plan view illustrating the resistor element of the exemplary embodiment illustrated in  FIG. 1 . 
     Referring to  FIG. 3 , the resistance layer  110  may substantially cover the entirety of the first surface  105 A between the terminals. The resistance layer  110  may be directly in contact with the first electrode layer  121  of the first terminal  120  and the first electrode layer  131  of the second terminal  130  at opposing ends of the resistance layer  110  in the first direction. Therefore, a current generated by a potential difference between the first terminal  120  and the second terminal  130  may flow through the resistance layer  110 . 
       FIG. 4  is a side view illustrating the resistor element of the exemplary embodiment illustrated in  FIG. 1 .  FIG. 5  is a cross-sectional view illustrating a cross section taken along a direction I-I′ of the resistor element of the exemplary embodiment illustrated in  FIG. 1 . 
     Referring to  FIGS. 4 and 5 , the resistance layer  110  may be formed on the first surface  105 A of the substrate  105 . In this case, when the resistor element  100  is mounted on the circuit board, the second surface  105 E may be disposed to be closer to the circuit board than the first surface  105 A. The second electrode layers  122  and  132  of the resistor element  100  may be directly connected to pads of the circuit board by solder bumps, or the like. 
     The first terminal  120  and the second terminal  130  may each include internal electrode layers and external electrode layers. Referring to  FIG. 5 , the first electrode layer  121  of the first terminal  120  may include a first internal electrode layer  121 A and a first external electrode layer  121 B. The second electrode layer  122  of the first terminal  120  may include a second internal electrode layer  122 E and a second external electrode layer  122 B. The first electrode layer  131  of the second terminal  130  may include a first internal electrode layer  131 A and a first external electrode layer  131 B, and the second electrode layer  132  of the second terminal  130  may include a second internal electrode layer  132 A and a second external electrode layer  132 B. 
     The internal electrode layers  121 A,  122 A,  131 A, and  132 A may be provided as a seed layer for forming the external electrode layers  121 B,  122 B,  131 B, and  132 B. The internal electrode layers  121 A,  122 A,  131 A, and  132 A may be formed by using a sputtering operation. The external electrode layers  121 B,  122 B,  131 B, and  132 B may be formed by a plating operation in which the internal electrode layers  121 A,  122 A,  131 A, and  132 A are used as the seed layer. At least some of the external electrode layers  121 B,  122 B,  131 B, and  132 B may also have a plurality of layers formed of different metal materials. 
       FIG. 6  is a front view illustrating the resistor element of the exemplary embodiment illustrated in  FIG. 1 .  FIG. 7  is a cross-sectional view illustrating a cross section taken along a direction II-II′ of the resistor element of the exemplary embodiment illustrated in  FIG. 1 . 
     Referring to  FIGS. 6 and 7 , a portion of the substrate  105  may be exposed within the first terminal  120 . The first terminal  120  may include the first electrode layer  121  formed on the first surface  105 A, the second electrode layer  122  formed on the second surface  105 B, and the side electrodes  123  electrically connecting the first electrode layer  121  and the second electrode layer  122  with each other. Referring to  FIG. 6 , a portion of the substrate  105  may be exposed between the side electrode layers  123 . 
     Referring to  FIG. 7 , the first electrode  121 , the second electrode layer  122 , and the side electrode layers  123  included in the first terminal  120  may each include the internal electrode layer  120 A and the external electrode layer  120 B. The internal electrode layer  120 A may be formed on the substrate  105 , and may be formed by a sputtering operation, or the like. When the internal electrode layer  120 A is formed, a side internal electrode layer  123 A may be formed simultaneously in an operation of forming the first internal electrode layer  121 A or the second internal electrode layer  122 A. The external electrode layer  120 B may be formed by a plating operation in which the internal electrode layer  120 A is used as a seed layer. 
       FIG. 8  is a perspective view illustrating a resistor element according to an exemplary embodiment. 
     Referring to  FIG. 8 , a resistor element  200  according to an exemplary embodiment may include a substrate  205 , a resistance layer  210 , and first and second terminals  220  and  230 . 
     In  FIG. 8 , the first terminal  220  may include a first electrode layer  221 , a second electrode layer  222 , and side electrode layers  223  connecting the first electrode layer  221  and the second electrode layer  222  with each other. The side electrode layers  223  may be separated from each other, and a portion of the substrate  205  may be exposed between the side electrode layers  223 . The first terminal  220  may include three side electrode layers  223 . Therefore, a current transfer path between the first electrode layer  221  and the second electrode layer  222  may be efficiently secured. Meanwhile, since the three side electrode layers  223  exist, the substrate  205  may be exposed in two regions separated from each other by the first terminal  220 . 
       FIG. 9  is a plan view illustrating the resistor element of the exemplary embodiment illustrated in  FIG. 8  and  FIG. 10  is a front view illustrating the resistor element of the exemplary embodiment illustrated in  FIG. 8 . 
     Referring to  FIGS. 9 and 10 , the first terminal  220  may include a first electrode layer  221  formed on the first surface  205 A of the substrate  205 , and a second electrode layer  222  formed on the second surface  205 B of the substrate  205 . The first electrode layer  221  and the second electrode layer  222  may be formed to face each other and be parallel with each other, and may be connected to each other by the side electrode layers  223 . 
     The side electrode layers  223  may be separated from each other in a second direction (Y axis direction), and a portion of the substrate  205  may be exposed between the side electrode layers  223 . Therefore, heat generated in the resistor element  200  during the operation may be efficiently discharged. 
       FIG. 11  is a perspective view illustrating a resistor element assembly including the resistor element according to the exemplary embodiment mounted on a circuit board. Although  FIG. 11  illustrates the resistor element  100  according to the exemplary embodiments described with reference to FIGS. through  7 , the resistor element assembly is not necessarily limited thereto. 
     Referring to  FIG. 11 , the resistor element assembly may include a circuit board  10  on which the resistor element  100  is mounted. The circuit board  10  may include first and second electrode pads  40  and  50 . The first and second electrode pads  40  and  50  may respectively be connected to the first terminal  120  and the second terminal  130  of the resistor element  100  by solder bumps  20  and  30 . In order to increase adhesion with the solder bumps  20  and  30 , the first terminal  120  and the second terminal  130  may include a tin (Sn) plated layer. 
       FIGS. 12 through 18  are views illustrating a method for manufacturing a resistor element according to an exemplary embodiment. 
     Referring to  FIG. 12 , a base substrate  101  may be provided. The base substrate  101  may have a first surface  101 A and a second surface  101 B facing the first surface  101 A. A plurality of through-holes H penetrating through the base substrate  101  may be formed. The plurality of through-holes H may have various shapes such as a circle, an ellipse, and a polygon. The plurality of through-holes H may be disposed in a matrix form when being viewed from the first surface  101 A of the base substrate  101 . 
     Referring to  FIG. 13 , a protection layer  103  may be formed on the base substrate  101 . The protection layer  103  may be formed on the surface of the base substrate  101  other than the plurality of through-holes H. Referring to  FIG. 13 , a region where the protection layer  103  is not formed in the base substrate  101  may be defined as a first region  102 . The first region  102  may include some regions of the first surface  101 A and the second surface  101 B of the base substrate  101 , and inner surfaces of the plurality of through-holes H. 
     Referring to  FIG. 14 , a seed metal layer  140  may be formed of a metal, a metal compound, or a metal oxide in the first region  102  in which the protection layer  103  is not formed. The seed metal layer  140  may include at least one of metals such as silver (Ag), copper (Cu), nickel (Ni), platinum (Pt) and the like, and may be formed by a sputtering operation. The seed metal layer  140  may be formed not only on the first surface  101 A and the second surface  101 B of the base substrate  101  but also on the inner surfaces of the plurality of through-holes H in which the protection layer  103  is not formed. When forming the seed metal layer  140  on the first surface  101 A and the second surface  101 B by the sputtering operation, the seed metal layer  140  may be simultaneously formed in the plurality of through-holes H. When the formation of the seed metal layer  140  is completed, the protection layer  103  may be removed as illustrated in  FIG. 15 . 
     Referring to  FIG. 16 , a resistance layer  110  may be formed on at least a portion of the region from which the protection layer  103  is removed. The resistance layer  110  may be formed of at least one of a Cu—Ni based alloy, a Ni—Cr based alloy, a Ru oxide, a Si oxide, manganese (Mn), and a Mn based alloy, and may be formed by coating and sintering a pasting the above-mentioned material by a screen printing method, or the like. 
     The resistance layer  110  may be only formed on the first surface  101 A and the second surface  101 B of the base substrate  101 . That is, in contrast to the protection layer  103  that is also formed on the side surfaces of the base substrate  101 , the resistance layer  110  may be only formed on the first surface  101 A and the second surface  101 B corresponding to a top surface and a bottom surface of the base substrate  101 . The resistance layer  110  may be formed to be connected to the internal metal layer  140  on the first surface  101 A and the second surface  101 B. 
     Referring to  FIG. 17 , the base substrate  101  may be divided into a plurality of unit elements along virtual lines C connecting the plurality of through-holes H to each other. The base substrate  101 , the resistance layer  110 , and the seed metal layer  140  may be divided into the plurality of unit elements by the dividing operation illustrated ire  FIG. 17 . Referring to  FIG. 18 , one unit element may include a substrate  105 , a resistance layer  110 , a first internal electrode  120 A, and a second internal electrode  130 A. The first internal electrode  120 A and the second internal electrode  130 A may be formed while the seed metal layer  140  is divided by the dividing operation. 
     Referring to  FIG. 18 , the first internal electrode  120 A may include a first internal electrode layer  121 A, a second internal electrode layer  122 A, and a side internal electrode layer  123 A. The first internal electrode layer  121 A and the second internal electrode layer  122 A may be each formed on the first surface  105 A and the second surface  105 B of the substrate  105 , and the side internal electrode layer  123 A may be formed on a portion of the side surface of the substrate  105 . Since the side internal electrode layer  123 A is formed only on the portion of the side surface of the substrate  105 , the portion of the side surface of the substrate  105  may be exposed between the side internal electrode layer  123 A and the first and second internal metal layers  121 A and  122 A. 
     The side internal metal layer  123 A may be a region formed in the plurality of through-holes H, in the operation of forming the internal metal layer  140  described with reference to  FIG. 14 . That is, there is no need to separately form a metal layer on the side surface of the substrate  105  in order to connect the first internal metal layer  141  and the second internal metal layer  142  each other. Therefore, since a total number of the operations is reduced, manufacturing cost may be saved and efficiency of a manufacturing operation may be increased. 
     The shape of the side internal metal layer  123 A may be defined along with a shape of the plurality of through-holes H formed in the base substrate  101  in the exemplary embodiment illustrated in  FIG. 12 . That is, when the plurality of through-holes H have a circular or elliptic shape, the side internal metal layer  123 A may be formed on a curved side surface of the substrate  105 . When the plurality of through-holes H have a polygonal shape, the side internal metal layer  123 A may also be formed on a side surface having a planar shape. 
     When the dividing operation illustrated in  FIG. 17  is completed, the first terminal  120  and the second terminal  130  as in the exemplary embodiment illustrated in  FIG. 1  may be formed by a plating operation using the first internal electrode  120 A and the second internal electrode  130 A as the seed layer. That is, shapes of the first terminal  120  and the second terminal  130  may be determined by the first internal electrode  120 A and the second internal electrode  130 A. Therefore, a portion of the side surface f the substrate  105  may be exposed from each of the first terminal  120  and the second terminal  130 . In this case, the side surface exposed from each of the first terminal  120  and the second terminal  130  may have an area smaller than other side surfaces of the substrate  105  exposed between the first terminal  120  and the second terminal  130 . 
     As set forth above, according to the exemplary embodiments, the resistor element capable of securing performance while reducing the number of manufacturing operations thereof may be provided. 
     Various advantages and effects of the inventive concepts are not limited to the description above, and may be more readily understood in the description of exemplary embodiments. 
     While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present invention as defined by the appended claims.