The present disclosure relates to a chip resistor and a method of manufacturing the same.
Japanese Patent Laying-Open No. 2018-4267 (PTL 1) discloses a shunt resistor including a resistive element, a first electrode, and a second electrode. The first electrode covers one end of the resistive element. The second electrode covers the other end of the resistive element opposite to the one end of the resistive element. The first electrode and the second electrode are distant from each other.
A resistance value of the shunt resistor described in PTL 1 is determined by an electrical resistivity of the resistive element, a cross-sectional area of the resistive element, and an interval between the first electrode and the second electrode. When an area of the first electrode and the second electrode is increased to improve heat radiation performance of the shunt resistor described in PTL 1, the interval between the first electrode and the second electrode decreases and the resistance value of the shunt resistor is varied from a designed resistance value. The present disclosure was made in view of the problem above, and an object thereof is to provide a chip resistor that achieves improved heat radiation performance independently of a resistance value.
A chip resistor in the present disclosure includes a resistive element, a first conductive underlying layer, a second conductive underlying layer, a first electrode, and a second electrode. The resistive element includes a first main surface, a second main surface opposite to the first main surface, a first side surface connected to the first main surface and the second main surface, and a second side surface opposite to the first side surface. The second side surface is connected to the first main surface and the second main surface. The first conductive underlying layer is provided on the first main surface of the resistive element. The second conductive underlying layer is provided on the first main surface of the resistive element and distant from the first conductive underlying layer. The first electrode is provided on a first side surface side of the resistive element and distant from the second conductive underlying layer. The second electrode is provided on a second side surface side of the resistive element and distant from the first conductive underlying layer and the first electrode. The first electrode includes a first electrode layer provided on the first main surface of the resistive element and the first conductive underlying layer. The second electrode includes a second electrode layer provided on the first main surface of the resistive element and the second conductive underlying layer. A first electrical resistivity of the first conductive underlying layer is higher than a second electrical resistivity of the first electrode layer and higher than a third electrical resistivity of the resistive element. A fourth electrical resistivity of the second conductive underlying layer is higher than a fifth electrical resistivity of the second electrode layer and higher than the third electrical resistivity of the resistive element.
A method of manufacturing a chip resistor in the present disclosure includes forming on a first main surface of a band-shaped resistive element, a first conductive underlying layer and a second conductive underlying layer distant from the first conductive underlying layer, forming a first conductive film on the first conductive underlying layer, the second conductive underlying layer, and a portion of the first main surface exposed from the first conductive underlying layer and the second conductive underlying layer, and dividing the band-shaped resistive element to form a resistive element including a first side surface and a second side surface. As a result of division of the band-shaped resistive element, the first conductive film is divided into a first electrode layer proximate to the first side surface and a second electrode layer proximate to the second side surface and distant from the first electrode layer. A first electrical resistivity of the first conductive underlying layer is higher than a second electrical resistivity of the first electrode layer and higher than a third electrical resistivity of the resistive element. A fourth electrical resistivity of the second conductive underlying layer is higher than a fifth electrical resistivity of the second electrode layer and higher than the third electrical resistivity of the resistive element.
According to the chip resistor in the present disclosure, heat radiation performance of a chip resistor can be improved independently of a resistance value thereof. According to the method of manufacturing a chip resistor in the present disclosure, a chip resistor that achieves improved heat radiation performance independently of a resistance value thereof can be obtained.
An embodiment will be described below. Identical features have identical reference characters allotted and description thereof will not be repeated.
A chip resistor in a first embodiment will be described with reference to
Resistive element 10 is formed, for example, of an electrically resistive material such as a Cu—Mn alloy, a Cu—Ni alloy, or an Ni—Cr alloy. Resistive element 10 includes a first main surface 11, a second main surface 12 opposite to first main surface 11, a first side surface 13a, a second side surface 13b opposite to first side surface 13a, a third side surface 14a, and a fourth side surface 14b opposite to third side surface 14a. First main surface 11 and second main surface 12 each extend in a first direction (an x direction) and a second direction (a y direction) perpendicular to the first direction (the x direction). For example, a longitudinal direction of resistive element 10 is defined as the first direction (the x direction). For example, a direction of a short side of resistive element 10 is defined as the second direction (the y direction). First main surface 11 and second main surface 12 are distant from each other in a third direction (a z direction) perpendicular to the first direction (the x direction) and the second direction (the y direction). A direction of thickness of resistive element 10 is defined as the third direction (the z direction). In mount of chip resistor 1 on a circuit board 50 (see
First side surface 13a is connected to first main surface 11 and second main surface 12. Second side surface 13b is connected to first main surface 11 and second main surface 12. First side surface 13a and second side surface 13b are distant from each other in the first direction (the x direction). Third side surface 14a is connected to first main surface 11 and second main surface 12 and connected to first side surface 13a and second side surface 13b. Fourth side surface 14b is connected to first main surface 11 and second main surface 12 and connected to first side surface 13a and second side surface 13b. Third side surface 14a and fourth side surface 14b are distant from each other in the second direction (the y direction). Resistive element 10 includes a central portion 10m exposed from first electrode 20 and second electrode 25 in a plan view of first main surface 11. Central portion 10m is arranged between first electrode 20 and second electrode 25 in the first direction (the x direction).
First insulating layer 15 is provided on first main surface 11 of resistive element 10. First insulating layer 15 is arranged between first electrode 20 and second electrode 25 and spaces first electrode 20 and second electrode 25 away from each other. First insulating layer 15 is arranged between a first electrode layer 21 and a second electrode layer 26 and spaces first electrode layer 21 and second electrode layer 26 away from each other. First insulating layer 15 is arranged between first conductive underlying layer 17 and second conductive underlying layer 18 and spaces first conductive underlying layer 17 and second conductive underlying layer 18 away from each other. First insulating layer 15 is formed on central portion 10m of resistive element 10. First insulating layer 15 protects resistive element 10. First insulating layer 15 includes a first end 15a proximate to first side surface 13a of resistive element 10 and a second end 15b proximate to second side surface 13b of resistive element 10. First insulating layer 15 is formed of an insulating resin such as an epoxy resin.
Second insulating layer 16 is provided on second main surface 12 of resistive element 10. Second insulating layer 16 is arranged between first electrode 20 and second electrode 25 and spaces first electrode 20 and second electrode 25 away from each other. Second insulating layer 16 is arranged between a third electrode layer 22 and a fourth electrode layer 27 and spaces third electrode layer 22 and fourth electrode layer 27 away from each other. Second insulating layer 16 is formed on central portion 10m of resistive element 10. Second insulating layer 16 protects resistive element 10. Second insulating layer 16 includes a third end 16a proximate to second side surface 13b of resistive element 10 and a fourth end 16b proximate to first side surface 13a of resistive element 10. Third end 16a of second insulating layer 16 may be in contact with fourth electrode layer 27. Fourth end 16b of second insulating layer 16 may be in contact with third electrode layer 22. Second insulating layer 16 is formed of an insulating resin such as an epoxy resin.
Insulating coating film 30 covers third side surface 14a of resistive element 10, fourth side surface 14b of resistive element 10, a first band-shaped region in first main surface 11 of resistive element 10 that is proximate to third side surface 14a, a second band-shaped region in first main surface 11 of resistive element 10 that is proximate to fourth side surface 14b, a third band-shaped region in second main surface 12 of resistive element 10 that is proximate to third side surface 14a, and a fourth band-shaped region in second main surface 12 of resistive element 10 that is proximate to fourth side surface 14b. Longitudinal directions of the first band-shaped region, the second band-shaped region, the third band-shaped region, and the fourth band-shaped region are defined as the first direction (the x direction). Insulating coating film 30 protects resistive element 10. Insulating coating film 30 is formed of an insulating resin such as an epoxy resin.
First conductive underlying layer 17 is provided on first main surface 11 of resistive element 10. First conductive underlying layer 17 is formed on a region in first main surface 11 of resistive element 10, that is proximate to first side surface 13a of resistive element 10 with respect to central portion 10m of resistive element 10. First conductive underlying layer 17 includes an end 17a proximate to first side surface 13a of resistive element 10 and an end 17b proximate to central portion 10m of resistive element 10. First conductive underlying layer 17 is provided also on first insulating layer 15. First end 15a of first insulating layer 15 is covered with first conductive underlying layer 17. End 17b of first conductive underlying layer 17 is exposed from first insulating layer 15. Ends 17a and 17b of first conductive underlying layer 17 are covered with first electrode layer 21. First conductive underlying layer 17 is formed, for example, of a conductive resin containing a binder resin (for example, an epoxy resin, a phenol resin, or a polyimide resin) and conductive particles (for example, silver particles) dispersed in the binder resin.
A first electrical resistivity of first conductive underlying layer 17 is higher than a second electrical resistivity of first electrode layer 21 and higher than a third electrical resistivity of resistive element 10. Therefore, while a current flows through chip resistor 1, substantially no current flows through first conductive underlying layer 17. First conductive underlying layer 17 does not substantially vary a resistance value of chip resistor 1.
The first electrical resistivity of first conductive underlying layer 17 is, for example, at least ten times as high as the second electrical resistivity of first electrode layer 21. The first electrical resistivity of first conductive underlying layer 17 may be at least twenty times, at least fifty times, or at least one hundred times as high as the second electrical resistivity of first electrode layer 21. The first electrical resistivity of first conductive underlying layer 17 is, for example, at least five times as high as the third electrical resistivity of resistive element 10. The first electrical resistivity of first conductive underlying layer 17 may be at least ten times, at least twenty-five times, or at least fifty times as high as the third electrical resistivity of resistive element 10.
Second conductive underlying layer 18 is provided on first main surface 11 of resistive element 10. Second conductive underlying layer 18 is formed on a region in first main surface 11 of resistive element 10, that is proximate to second side surface 13b of resistive element 10 with respect to central portion 10m of resistive element 10. Second conductive underlying layer 18 includes an end 18a proximate to second side surface 13b of resistive element 10 and an end 18b proximate to central portion 10m of resistive element 10. Second conductive underlying layer 18 is provided also on first insulating layer 15. Second end 15b of first insulating layer 15 is covered with second conductive underlying layer 18. End 18b of second conductive underlying layer 18 is exposed from first insulating layer 15. Ends 18a and 18b of second conductive underlying layer 18 are covered with second electrode layer 26. Second conductive underlying layer 18 is distant from first conductive underlying layer 17 in the first direction (the x direction). Second conductive underlying layer 18 is formed, for example, of a conductive resin containing a binder resin (for example, an epoxy resin, a phenol resin, or a polyimide resin) and conductive particles (for example, silver particles) dispersed in the binder resin.
A fourth electrical resistivity of second conductive underlying layer 18 is higher than a fifth electrical resistivity of second electrode layer 26 and higher than the third electrical resistivity of resistive element 10. Therefore, while a current flows through chip resistor 1, substantially no current flows through second conductive underlying layer 18. Second conductive underlying layer 18 does not substantially vary a resistance value of chip resistor 1.
The fourth electrical resistivity of second conductive underlying layer 18 is, for example, at least ten times as high as the fifth electrical resistivity of second electrode layer 26. The fourth electrical resistivity of second conductive underlying layer 18 may be at least twenty times, at least fifty times, or at least one hundred times as high as the fifth electrical resistivity of second electrode layer 26. The fourth electrical resistivity of second conductive underlying layer 18 is, for example, at least five times as high as the third electrical resistivity of resistive element 10. The fourth electrical resistivity of second conductive underlying layer 18 may be at least ten times, at least twenty-five times, or at least fifty times as high as the third electrical resistivity of resistive element 10.
First electrode 20 is provided on a first side surface 13a side of resistive element 10. First electrode 20 is proximate to first side surface 13a of resistive element 10 with respect to central portion 10m of resistive element 10 in the first direction (the x direction). First electrode 20 extends along first side surface 13a of resistive element 10. First electrode 20 is distant from second conductive underlying layer 18 and second electrode 25 in the first direction (the x direction). First electrode 20 includes first electrode layer 21, third electrode layer 22, and a first thin metal layer 23.
First electrode layer 21 is provided on first main surface 11 of resistive element 10 and first conductive underlying layer 17. First electrode layer 21 is proximate to first side surface 13a of resistive element 10 and extends along first side surface 13a of resistive element 10. In the plan view of first main surface 11 or second main surface 12, a first portion 21m of first electrode layer 21 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 is more proximate to central portion 10m of resistive element 10 than a third portion 22m of third electrode layer 22 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 or flush with third portion 22m of third electrode layer 22.
A thickness of first electrode layer 21 on first conductive underlying layer 17 is much smaller than the thickness of first electrode layer 21 on first main surface 11 of resistive element 10. The thickness of first electrode layer 21 on first conductive underlying layer 17 is, for example, at most 0.1 time as large as the thickness of first electrode layer 21 on first main surface 11 of resistive element 10. The second electrical resistivity of first electrode layer 21 is lower than the third electrical resistivity of resistive element 10. First electrode layer 21 is formed, for example, of a metal such as copper. First electrode layer 21 is, for example, a plated layer.
Third electrode layer 22 is provided on second main surface 12 of resistive element 10. A ninth electrical resistivity of third electrode layer 22 is lower than the third electrical resistivity of resistive element 10. Third electrode layer 22 is formed, for example, of a metal such as copper. Third electrode layer 22 is, for example, a plated layer.
First thin metal layer 23 electrically connects first electrode layer 21 and third electrode layer 22 to each other. First thin metal layer 23 covers first electrode layer 21, third electrode layer 22, and first side surface 13a of resistive element 10. First thin metal layer 23 is formed of a conductive material containing tin such as a solder layer. First thin metal layer 23 is, for example, a plated layer.
Second electrode 25 is provided on a second side surface 13b side of resistive element 10. Second electrode 25 is proximate to second side surface 13b of resistive element 10 with respect to central portion 10m of resistive element 10 in the first direction (the x direction). Second electrode 25 extends along second side surface 13b of resistive element 10. Second electrode 25 is distant from first conductive underlying layer 17 and first electrode 20 in the first direction (the x direction). Second electrode 25 includes second electrode layer 26, fourth electrode layer 27, and a second thin metal layer 28.
Second electrode layer 26 is provided on first main surface 11 of resistive element 10 and second conductive underlying layer 18. Second electrode layer 26 is proximate to second side surface 13b of resistive element 10 and extends along second side surface 13b of resistive element 10. In the plan view of first main surface 11 or second main surface 12, a second portion 26m of second electrode layer 26 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 is more proximate to central portion 10m of resistive element 10 than a fourth portion 27m of fourth electrode layer 27 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 or flush with fourth portion 27m of fourth electrode layer 27.
A thickness of second electrode layer 26 on second conductive underlying layer 18 is much smaller than the thickness of second electrode layer 26 on first main surface 11 of resistive element 10. The thickness of second electrode layer 26 on second conductive underlying layer 18 is, for example, at most 0.1 time as large as the thickness of second electrode layer 26 on first main surface 11 of resistive element 10. The fifth electrical resistivity of second electrode layer 26 is lower than the third electrical resistivity of resistive element 10. Second electrode layer 26 is formed, for example, of a metal such as copper. Second electrode layer 26 is, for example, a plated layer.
Fourth electrode layer 27 is provided on second main surface 12 of resistive element 10. Fourth electrode layer 27 is distant from third electrode layer 22 in the first direction (the x direction). A seventh electrical resistivity of fourth electrode layer 27 is lower than the third electrical resistivity of resistive element 10. Fourth electrode layer 27 is formed, for example, of a metal such as copper. Fourth electrode layer 27 is, for example, a plated layer.
Second thin metal layer 28 electrically connects second electrode layer 26 and fourth electrode layer 27 to each other. Second thin metal layer 28 covers second electrode layer 26, fourth electrode layer 27, and second side surface 13b of resistive element 10. Second thin metal layer 28 is formed of a conductive material containing tin such as a solder layer. Second thin metal layer 28 is, for example, a plated layer.
First portion 21m of first electrode layer 21 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 is more proximate to central portion 10m of resistive element 10 than third portion 22m of third electrode layer 22 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 or flush with third portion 22m of third electrode layer 22. Second portion 26m of second electrode layer 26 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 is more proximate to central portion 10m of resistive element 10 than fourth portion 27m of fourth electrode layer 27 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 or flush with fourth portion 27m of fourth electrode layer 27. Therefore, the resistance value of chip resistor 1 is dependent on a distance L (see
In contrast, as described already, first conductive underlying layer 17 and second conductive underlying layer 18 do not substantially vary the resistance value of chip resistor 1. In other words, even when a size of first conductive underlying layer 17 and a size of second conductive underlying layer 18 vary, the resistance value of chip resistor 1 does not substantially vary unless distance L varies.
Therefore, though the resistance value of chip resistor 1 is dependent on distance L, it is not dependent on the size of first electrode 20 (first electrode layer 21) or second electrode 25 (second electrode layer 26). Heat radiation performance of chip resistor 1 can be improved independently of the resistance value of chip resistor 1.
Referring to
An exemplary method of manufacturing chip resistor 1 in the present embodiment will be described with reference to
Referring to
Referring to
First insulating layer 15 and second insulating layer 16 are formed, for example, of an insulating resin such as an epoxy resin. First insulating layer 15 and second insulating layer 16 are provided, for example, by printing such as screen printing.
Referring to
Referring to
Referring to
First conductive film 40 and second conductive film 41 are provided, for example, by plating. First conductive film 40 and second conductive film 41 are each, for example, a metal plated film. Resistive element 10, first conductive underlying layer 17, and second conductive underlying layer 18 are conductive, whereas first insulating layer 15, second insulating layer 16, and insulating coating film 30 are electrically insulating. Therefore, first conductive film 40 is selectively formed on first conductive underlying layer 17, second conductive underlying layer 18, and the portion of first main surface 11 of resistive element 10 that is exposed from first insulating layer 15, insulating coating film 30, first conductive underlying layer 17, and second conductive underlying layer 18. Second conductive film 41 is selectively formed on the portion of second main surface 12 of resistive element 10 that is exposed from second insulating layer 16 and insulating coating film 30.
The first electrical resistivity of first conductive underlying layer 17 is lower than the third electrical resistivity of resistive element 10. The fourth electrical resistivity of second conductive underlying layer 18 is lower than the third electrical resistivity of resistive element 10. Therefore, when first conductive film 40 is formed, for example, by plating, the thickness of first conductive film 40 on first conductive underlying layer 17 becomes much smaller than the thickness of first conductive film 40 on first main surface 11 of resistive element 10 and the thickness of first conductive film 40 on second conductive underlying layer 18 becomes much smaller than the thickness of first conductive film 40 on first main surface 11 of resistive element 10.
Referring to
The method of manufacturing chip resistor 1 in the present embodiment includes forming first thin metal layer 23 and second thin metal layer 28. First thin metal layer 23 electrically connects first electrode layer 21 and third electrode layer 22 to each other. First thin metal layer 23 covers first electrode layer 21, third electrode layer 22, and first side surface 13a of resistive element 10. Second thin metal layer 28 electrically connects second electrode layer 26 and fourth electrode layer 27 to each other. Second thin metal layer 28 covers second electrode layer 26, fourth electrode layer 27, and second side surface 13b of resistive element 10. First thin metal layer 23 and second thin metal layer 28 are formed, for example, of a conductive material containing tin such as a solder layer.
First thin metal layer 23 and second thin metal layer 28 are provided, for example, by plating. First thin metal layer 23 and second thin metal layer 28 are each, for example, a metal plated film. First electrode layer 21, second electrode layer 26, resistive element 10, third electrode layer 22, and fourth electrode layer 27 are conductive, whereas first insulating layer 15, second insulating layer 16, and insulating coating film 30 are electrically insulating. Therefore, first thin metal layer 23 is selectively formed on first electrode layer 21, second electrode layer 26, and first side surface 13a of resistive element 10. Second thin metal layer 28 is selectively formed on third electrode layer 22, fourth electrode layer 27, and second side surface 13b of resistive element 10. Chip resistor 1 shown in
Effects of chip resistor 1 and the method of manufacturing the same in the present embodiment will be described.
Chip resistor 1 in the present embodiment includes resistive element 10, first conductive underlying layer 17, second conductive underlying layer 18, first electrode 20, and second electrode 25. Resistive element 10 includes first main surface 11, second main surface 12 opposite to first main surface 11, first side surface 13a connected to first main surface 11 and second main surface 12, and second side surface 13b opposite to first side surface 13a. Second side surface 13b is connected to first main surface 11 and second main surface 12. First conductive underlying layer 17 is provided on first main surface 11 of resistive element 10. Second conductive underlying layer 18 is provided on first main surface 11 of resistive element 10 and distant from first conductive underlying layer 17. First electrode 20 is provided on the first side surface 13a side of resistive element 10 and distant from second conductive underlying layer 18. Second electrode 25 is provided on the second side surface 13b side of resistive element 10 and distant from first conductive underlying layer 17 and first electrode 20. First electrode 20 includes first electrode layer 21 provided on first main surface 11 of resistive element 10 and first conductive underlying layer 17. Second electrode 25 includes second electrode layer 26 provided on first main surface 11 of resistive element 10 and second conductive underlying layer 18. The first electrical resistivity of first conductive underlying layer 17 is higher than the second electrical resistivity of first electrode layer 21 and higher than the third electrical resistivity of resistive element 10. The fourth electrical resistivity of second conductive underlying layer 18 is higher than the fifth electrical resistivity of second electrode layer 26 and higher than the third electrical resistivity of resistive element 10.
Therefore, though the resistance value of chip resistor 1 is dependent on distance L (see
As set forth above, though the resistance value of chip resistor 1 is dependent on distance L (see
In chip resistor 1 in the present embodiment, first conductive underlying layer 17 and second conductive underlying layer 18 are formed of a conductive resin containing a binder resin and conductive particles (for example, silver particles) dispersed in the binder resin. First electrode layer 21 and second electrode layer 26 are formed of a metal. Therefore, heat radiation performance of chip resistor 1 can be improved independently of the resistance value of chip resistor 1. Cost for manufacturing chip resistor 1 can be reduced.
Chip resistor 1 in the present embodiment further includes first insulating layer 15 provided on first main surface 11 of resistive element 10. First insulating layer 15 is arranged between first electrode 20 and second electrode 25 and arranged between first conductive underlying layer 17 and second conductive underlying layer 18.
First insulating layer 15 protects resistive element 10. Chip resistor 1 has a longer lifetime. First insulating layer 15 prevents first conductive underlying layer 17 and second conductive underlying layer 18 from coming in contact with each other and prevents first electrode layer 21 and second electrode layer 26 from coming in contact with each other.
In chip resistor 1 in the present embodiment, first end 15a of first insulating layer 15 proximate to first side surface 13a of resistive element 10 is covered with first conductive underlying layer 17. Second end 15b of first insulating layer 15 proximate to second side surface 13b of resistive element 10 is covered with second conductive underlying layer 18. Chip resistor 1 in the present embodiment can achieve improved heat radiation performance independently of the resistance value thereof.
In chip resistor 1 in the present embodiment, first electrode 20 further includes third electrode layer 22 and first thin metal layer 23. Third electrode layer 22 is provided on second main surface 12 of resistive element 10. First thin metal layer 23 electrically connects first electrode layer 21 and third electrode layer 22 to each other. Second electrode 25 further includes fourth electrode layer 27 and second thin metal layer 28. Fourth electrode layer 27 is provided on second main surface 12 of resistive element 10 and distant from third electrode layer 22. Second thin metal layer 28 electrically connects second electrode layer 26 and fourth electrode layer 27 to each other.
When chip resistor 1 is mounted on circuit board 50 (see
In chip resistor 1 in the present embodiment, resistive element 10 includes central portion 10m exposed from first electrode 20 and second electrode 25 in the plan view of first main surface 11. First portion 21m of first electrode layer 21 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 is more proximate to central portion 10m of resistive element 10 than third portion 22m of third electrode layer 22 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 or flush with third portion 22m of third electrode layer 22. Second portion 26m of second electrode layer 26 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 is more proximate to central portion 10m of resistive element 10 than fourth portion 27m of fourth electrode layer 27 that is in contact with resistive element 10 and most proximate to central portion 10m of resistive element 10 or flush with fourth portion 27m of fourth electrode layer 27.
Though the resistance value of chip resistor 1 is dependent on distance L between first portion 21m of first electrode layer 21 and second portion 26m of second electrode layer 26, it is not dependent on the size of first electrode 20 and the size of second electrode 25. Chip resistor 1 in the present embodiment can achieve improved heat radiation performance independently of the resistance value thereof.
In chip resistor 1 in the present embodiment, first thin metal layer 23 and second thin metal layer 28 are each formed of a conductive material containing tin. Therefore, chip resistor 1 can readily be mounted on circuit board 50 (see
Chip resistor 1 in the present embodiment further includes second insulating layer 16 provided on second main surface 12 of resistive element 10. Second insulating layer 16 is arranged between third electrode layer 22 and fourth electrode layer 27.
Second insulating layer 16 protects resistive element 10. Chip resistor 1 has a longer lifetime. Second insulating layer 16 prevents third electrode layer 22 and fourth electrode layer 27 from coming in contact with each other.
In chip resistor 1 in the present embodiment, chip resistor 1 is a shunt resistor. Therefore, heat radiation performance of chip resistor 1 can be improved independently of the resistance value thereof. Chip resistor 1 suitable for detection of a current can be provided.
The method of manufacturing chip resistor 1 in the present embodiment includes forming on first main surface 11 of band-shaped resistive element 10a, first conductive underlying layer 17 and second conductive underlying layer 18 distant from first conductive underlying layer 17 and forming first conductive film 40 on first conductive underlying layer 17, second conductive underlying layer 18, and the portion of first main surface 11 of band-shaped resistive element 10a exposed from first conductive underlying layer 17 and second conductive underlying layer 18. The method of manufacturing chip resistor 1 in the present embodiment further includes dividing band-shaped resistive element 10a to form resistive element 10 including first side surface 13a and second side surface 13b. As a result of division of band-shaped resistive element 10a, first conductive film 40 is divided into first electrode layer 21 proximate to first side surface 13a and second electrode layer 26 proximate to second side surface 13b and distant from first electrode layer 21. The first electrical resistivity of first conductive underlying layer 17 is higher than the second electrical resistivity of first electrode layer 21 and higher than the third electrical resistivity of resistive element 10. The fourth electrical resistivity of second conductive underlying layer 18 is higher than the fifth electrical resistivity of second electrode layer 26 and higher than the third electrical resistivity of resistive element 10.
Therefore, though the resistance value of chip resistor 1 is dependent on distance L (see
As set forth above, though the resistance value of chip resistor 1 is dependent on distance L (see
In the method of manufacturing chip resistor 1 in the present embodiment, first conductive underlying layer 17 and second conductive underlying layer 18 are provided by printing. First conductive film 40 is provided by plating. Therefore, productivity of chip resistor 1 can be improved and cost for manufacturing chip resistor 1 can be reduced.
A chip resistor 1b in a second embodiment will be described with reference to
Chip resistor 1b further includes a third conductive underlying layer 33. Chip resistor 1b may further include a third insulating layer 35.
Third conductive underlying layer 33 is provided on second main surface 12 of resistive element 10 and second insulating layer 16. Third conductive underlying layer 33 is in contact with fourth electrode layer 27 and distant from third electrode layer 22 in the first direction (the x direction). A part of third conductive underlying layer 33 is exposed from third insulating layer 35. Third conductive underlying layer 33 includes an end 33a proximate to first side surface 13a. End 33a of third conductive underlying layer 33 is covered with third insulating layer 35. End 33a of third conductive underlying layer 33 is distant from third electrode layer 22 in the first direction (the x direction).
Third end 16a of second insulating layer 16 proximate to second side surface 13b of resistive element 10 is covered with third conductive underlying layer 33. In the plan view of second main surface 12 of resistive element 10, third conductive underlying layer 33 overlaps with second conductive underlying layer 18. In the plan view of second main surface 12 of resistive element 10, third conductive underlying layer 33 overlaps with central portion 10m of resistive element 10 in the first direction (the x direction) in which first electrode 20 and second electrode 25 are distant from each other. In the plan view of second main surface 12 of resistive element 10, third conductive underlying layer 33 may overlap with first conductive underlying layer 17. Fourth end 16b of second insulating layer 16 proximate to first side surface 13a of resistive element 10 is exposed from third conductive underlying layer 33.
A sixth electrical resistivity of third conductive underlying layer 33 is higher than the seventh electrical resistivity of fourth electrode layer 27 and higher than the third electrical resistivity of resistive element 10. Therefore, when a current flows through chip resistor 1, substantially no current flows through third conductive underlying layer 33. Third conductive underlying layer 33 does not substantially vary the resistance value of chip resistor 1.
The sixth electrical resistivity of third conductive underlying layer 33 is, for example, at least ten times as high as the seventh electrical resistivity of fourth electrode layer 27. The sixth electrical resistivity of third conductive underlying layer 33 may be at least twenty times, at least fifty times, or at least one hundred times as high as the seventh electrical resistivity of fourth electrode layer 27. The sixth electrical resistivity of third conductive underlying layer 33 is, for example, at least five times as high as the third electrical resistivity of resistive element 10. The sixth electrical resistivity of third conductive underlying layer 33 may be at least ten times, at least twenty-five times, or at least fifty times as high as the third electrical resistivity of resistive element 10. Third conductive underlying layer 33 is formed of a conductive resin containing a binder resin (for example, an epoxy resin, a phenol resin, or a polyimide resin) and conductive particles (for example, silver particles) dispersed in the binder resin.
Fourth electrode layer 27 is further provided on third conductive underlying layer 33. A thickness of fourth electrode layer 27 on third conductive underlying layer 33 is much smaller than the thickness of fourth electrode layer 27 on first main surface 11 of resistive element 10. The thickness of fourth electrode layer 27 on third conductive underlying layer 33 is, for example, at most 0.1 time as large as the thickness of fourth electrode layer 27 on first main surface 11 of resistive element 10.
Third insulating layer 35 is provided on third conductive underlying layer 33 and second insulating layer 16. Third insulating layer 35 protects third conductive underlying layer 33. Third insulating layer 35 is formed of an insulating resin such as an epoxy resin.
A method of manufacturing chip resistor 1b in the present embodiment will be described with reference to
The method of manufacturing chip resistor 1c in the present embodiment includes the steps shown in
Third end 16a of second insulating layer 16 is covered with third conductive underlying layer 33. In the plan view of second main surface 12 of band-shaped resistive element 10a, third conductive underlying layer 33 overlaps with second conductive underlying layer 18. In the plan view of second main surface 12 of band-shaped resistive element 10a, third conductive underlying layer 33 may overlap with first conductive underlying layer 17. Fourth end 16b of second insulating layer 16 is exposed from third conductive underlying layer 33.
Third conductive underlying layer 33 is formed, for example, of a conductive resin containing a binder resin (for example, an epoxy resin, a phenol resin, or a polyimide resin) and conductive particles (for example, silver particles) dispersed in the binder resin. Third conductive underlying layer 33 is provided, for example, by printing such as screen printing.
Referring to
Referring to
Referring to
The sixth electrical resistivity of third conductive underlying layer 33 is lower than the third electrical resistivity of resistive element 10. Therefore, when second conductive film 41 is formed, for example, by plating, the thickness of second conductive film 41 on third electrode layer 33 becomes much smaller than the thickness of second electrode layer 41 on first main surface 11 of resistive element 10.
Referring to
The method of manufacturing chip resistor 1b in the present embodiment includes forming first thin metal layer 23 and second thin metal layer 28 similarly to the method of manufacturing chip resistor 1 in the first embodiment. Chip resistor 1b shown in
Chip resistor 1b and the method of manufacturing the same in the present embodiment achieve effects below in addition to the effects of chip resistor 1 and the method of manufacturing the same in the first embodiment.
Chip resistor 1b in the present embodiment further includes third conductive underlying layer 33 provided on second main surface 12 of resistive element 10 and second insulating layer 16. Third conductive underlying layer 33 is in contact with fourth electrode layer 27 and distant from third electrode layer 22. Third end 16a of second insulating layer 16 proximate to second side surface 13b of resistive element 10 is covered with third conductive underlying layer 33. The sixth electrical resistivity of third conductive underlying layer 33 is higher than the seventh electrical resistivity of fourth electrode layer 27 and higher than the third electrical resistivity of resistive element 10.
When chip resistor 1b is mounted on circuit board 50 (see
In chip resistor 1b in the present embodiment, in the plan view of second main surface 12 of resistive element 10, third conductive underlying layer 33 overlaps with central portion 10m of resistive element 10 in the direction (the first direction (the x direction)) in which first electrode 20 and second electrode 25 are distant from each other.
When chip resistor 1b is mounted on circuit board 50 (see
In chip resistor 1b in the present embodiment, third conductive underlying layer 33 is formed of a conductive resin containing a binder resin and conductive particles dispersed in the binder resin. Fourth electrode layer 27 is formed of a metal. Therefore, heat radiation performance of chip resistor 1b can be improved independently of the resistance value thereof. Cost for manufacturing chip resistor 1b can be reduced.
The method of manufacturing chip resistor 1b in the present embodiment further includes forming second insulating layer 16 on second main surface 12 of band-shaped resistive element 10a opposite to first main surface 11 of band-shaped resistive element 10a, forming third conductive underlying layer 33 on second main surface 12 of band-shaped resistive element 10a and second insulating layer 16, forming second conductive film 41 on third conductive underlying layer 33 and the portion of second main surface 12 of band-shaped resistive element 10a that is exposed from third conductive underlying layer 33, and forming first thin metal layer 23 and second thin metal layer 28. As a result of division of band-shaped resistive element 10a, second conductive film 41 is divided into third electrode layer 22 proximate to first side surface 13a and fourth electrode layer 27 proximate to second side surface 13b and distant from third electrode layer 22. Third conductive underlying layer 33 is in contact with fourth electrode layer 27 and distant from third electrode layer 22. First thin metal layer 23 electrically connects first electrode layer 21 and third electrode layer 22 to each other. Second thin metal layer 28 electrically connects second electrode layer 26 and fourth electrode layer 27 to each other. The sixth electrical resistivity of third conductive underlying layer 33 is higher than the seventh electrical resistivity of fourth electrode layer 27 and higher than the third electrical resistivity of resistive element 10.
When chip resistor 1b is mounted on circuit board 50 (see
In the method of manufacturing chip resistor 1b in the present embodiment, third conductive underlying layer 33 is provided by printing. Second conductive film 41 is provided by plating. Therefore, productivity of chip resistor 1b can be improved and cost for manufacturing chip resistor 1b can be reduced.
A chip resistor 1c in a third embodiment will be described with reference to
Chip resistor 1c further includes a fourth conductive underlying layer 34. Fourth conductive underlying layer 34 is provided on second main surface 12 of resistive element 10 and second insulating layer 16. Fourth conductive underlying layer 34 is in contact with third electrode layer 22 and distant from third conductive underlying layer 33 and fourth electrode layer 27 in the first direction (the x direction). A part of fourth conductive underlying layer 34 is exposed from third insulating layer 35. Fourth conductive underlying layer 34 includes an end 34a proximate to second side surface 13b. End 34a of fourth conductive underlying layer 34 is covered with third insulating layer 35. End 34a of fourth conductive underlying layer 34 is distant from end 33a of third conductive underlying layer 33 and fourth electrode layer 27 in the first direction (the x direction).
Fourth end 16b of second insulating layer 16 proximate to first side surface 13a of resistive element 10 is covered with fourth conductive underlying layer 34. In the plan view of second main surface 12 of resistive element 10, fourth conductive underlying layer 34 overlaps with first conductive underlying layer 17. In the plan view of second main surface 12 of resistive element 10, fourth conductive underlying layer 34 is distant from central portion 10m of resistive element 10 in the first direction (the x direction) in which first electrode 20 and second electrode 25 are distant from each other.
An eighth electrical resistivity of fourth conductive underlying layer 34 is higher than the ninth electrical resistivity of third electrode layer 22 and higher than the third electrical resistivity of resistive element 10. Therefore, when a current flows through chip resistor 1, substantially no current flows through fourth conductive underlying layer 34. Fourth conductive underlying layer 34 does not substantially vary the resistance value of chip resistor 1.
The eighth electrical resistivity of fourth conductive underlying layer 34 is, for example, at least ten times as high as the ninth electrical resistivity of third electrode layer 22. The eighth electrical resistivity of fourth conductive underlying layer 34 may be at least twenty times, at least fifty times, or at least one hundred times as high as the ninth electrical resistivity of third electrode layer 22. The eighth electrical resistivity of fourth conductive underlying layer 34 is, for example, at least five times as high as the third electrical resistivity of resistive element 10. The eighth electrical resistivity of fourth conductive underlying layer 34 may be at least ten times, at least twenty-five times, or at least fifty times as high as the third electrical resistivity of resistive element 10. Fourth conductive underlying layer 34 is formed of a conductive resin containing a binder resin (for example, an epoxy resin, a phenol resin, or a polyimide resin) and conductive particles (for example, silver particles) dispersed in the binder resin.
Third electrode layer 22 is further provided on fourth conductive underlying layer 34. A thickness of third electrode layer 22 on fourth conductive underlying layer 34 is much smaller than the thickness of third electrode layer 22 on first main surface 11 of resistive element 10. The thickness of third electrode layer 22 on fourth conductive underlying layer 34 is, for example, at most 0.1 time as large as the thickness of third electrode layer 22 on first main surface 11 of resistive element 10.
Third insulating layer 35 is provided on third conductive underlying layer 33, fourth conductive underlying layer 34, and second insulating layer 16. Third insulating layer 35 protects third conductive underlying layer 33 and fourth conductive underlying layer 34.
A method of manufacturing chip resistor 1c in the present embodiment will be described with reference to
The method of manufacturing chip resistor 1c in the present embodiment includes the steps shown in
Fourth end 16b of second insulating layer 16 is covered with fourth conductive underlying layer 34. In the plan view of second main surface 12 of band-shaped resistive element 10a, fourth conductive underlying layer 34 overlaps with first conductive underlying layer 17. Fourth conductive underlying layer 34 is distant from third conductive underlying layer 33 in the first direction (the x direction).
Fourth conductive underlying layer 34 is formed, for example, of a conductive resin containing a binder resin (for example, an epoxy resin, a phenol resin, or a polyimide resin) and conductive particles (for example, silver particles) dispersed in the binder resin. Fourth conductive underlying layer 34 is provided, for example, by printing such as screen printing.
Referring to
Referring to
Referring to
The eighth electrical resistivity of fourth conductive underlying layer 34 is lower than the third electrical resistivity of resistive element 10. Therefore, when second conductive film 41 is formed, for example, by plating, the thickness of second conductive film 41 on fourth conductive underlying layer 34 becomes much smaller than the thickness of second conductive film 41 on first main surface 11 of resistive element 10.
Referring to
The method of manufacturing chip resistor 1c in the present embodiment includes forming first thin metal layer 23 and second thin metal layer 28 similarly to the method of manufacturing chip resistor 1b in the second embodiment. Chip resistor 1c shown in
Chip resistor 1c and the method of manufacturing the same in the present embodiment achieve effects below in addition to the effects of chip resistor 1b and the method of manufacturing the same in the second embodiment.
Chip resistor 1c in the present embodiment further includes fourth conductive underlying layer 34 provided on second main surface 12 of resistive element 10 and second insulating layer 16. Fourth conductive underlying layer 34 is in contact with third electrode layer 22 and distant from third conductive underlying layer 33 and fourth electrode layer 27. Fourth end 16b of second insulating layer 16 proximate to first side surface 13a of resistive element 10 is covered with fourth conductive underlying layer 34. The eighth electrical resistivity of fourth conductive underlying layer 34 is higher than the ninth electrical resistivity of third electrode layer 22 and higher than the third electrical resistivity of resistive element 10.
When chip resistor 1c is mounted on circuit board 50 (see
In chip resistor 1c in the present embodiment, fourth conductive underlying layer 34 is formed of a conductive resin containing a binder resin and conductive particles dispersed in the binder resin. Third electrode layer 22 is formed of a metal. Therefore, heat radiation performance of chip resistor 1c can be improved independently of the resistance value thereof. Cost for manufacturing chip resistor 1c can be reduced.
The method of manufacturing chip resistor 1c in the present embodiment further includes forming fourth conductive underlying layer 34 distant from third conductive underlying layer 33, on second main surface 12 of band-shaped resistive element 10a and second insulating layer 16. Second conductive film 41 is formed also on fourth conductive underlying layer 34. Fourth conductive underlying layer 34 is in contact with third electrode layer 22 and distant from fourth electrode layer 27. The eighth electrical resistivity of fourth conductive underlying layer 34 is higher than the ninth electrical resistivity of third electrode layer 22 and higher than the third electrical resistivity of resistive element 10.
When chip resistor 1c is mounted on circuit board 50 (see
In the method of manufacturing chip resistor 1c in the present embodiment, fourth conductive underlying layer 34 is provided by printing. Therefore, productivity of chip resistor 1c can be improved and cost for manufacturing chip resistor 1c can be reduced.
A chip resistor 1d in a fourth embodiment will be described with reference to
First insulating layer 15 is provided also on first conductive underlying layer 17. First end 15a of first insulating layer 15 is exposed from first conductive underlying layer 17. End 17b of first conductive underlying layer 17 is covered with first insulating layer 15. End 17b of first conductive underlying layer 17 is distant from first electrode layer 21. First insulating layer 15 is provided also on second conductive underlying layer 18. Second end 15b of first insulating layer 15 is exposed from first conductive underlying layer 17. End 18b of second conductive underlying layer 18 is covered with first insulating layer 15. End 18b of second conductive underlying layer 18 is distant from second electrode layer 26.
A method of manufacturing chip resistor 1d in the present embodiment will be described with reference to
The method of manufacturing chip resistor 1d in the present embodiment includes the step shown in
First conductive underlying layer 17 includes end 17a which is an end of first conductive underlying layer 17 in the first direction (the x direction) and end 17b which is an end of first conductive underlying layer 17 in the first direction (the x direction) and opposite to end 17a. Second conductive underlying layer 18 includes end 18a which is an end of second conductive underlying layer 18 in the first direction (the x direction) and end 18b which is an end of second conductive underlying layer 18 in the first direction (the x direction) and opposite to end 18a. End 17b of first conductive underlying layer 17 is opposed to end 18b of second conductive underlying layer 18. First conductive underlying layer 17 and second conductive underlying layer 18 are provided, for example, by printing such as screen printing.
Referring to
First insulating layer 15 includes first end 15a which is an end of first insulating layer 15 in the first direction (the x direction) and second end 15b which is an end of first insulating layer 15 in the first direction (the x direction) and opposite to first end 15a. First end 15a of first insulating layer 15 is located on first conductive underlying layer 17 and covers end 17b of first conductive underlying layer 17. Second end 15b of first insulating layer 15 is located on second conductive underlying layer 18 and covers end 18b of second conductive underlying layer 18. Second insulating layer 16 includes third end 16a which is an end of second insulating layer 16 in the first direction (the x direction) and fourth end 16b which is an end of second insulating layer 16 in the first direction (the x direction) and opposite to third end 16a.
Referring to
Chip resistor 1d in the present embodiment achieves effects below similar to those of chip resistor 1 in the first embodiment.
In chip resistor 1d in the present embodiment, resistive element 10 includes central portion 10m exposed from first electrode 20 and second electrode 25 in the plan view of first main surface 11. End 17b of first conductive underlying layer 17 proximate to central portion 10m of resistive element 10 is covered with first insulating layer 15. End 18b of second conductive underlying layer 18 proximate to central portion 10m of resistive element 10 is covered with first insulating layer 15. Chip resistor 1d in the present embodiment can achieve improved heat radiation performance independently of the resistance value thereof.
It should be understood that the first to fourth embodiments disclosed herein are illustrative and non-restrictive in every respect. At least two of the first to fourth embodiments disclosed herein may be combined unless there is inconsistency. For example, third conductive underlying layer 33 and third insulating layer 35 in the second embodiment may be provided in chip resistor 1d in the fourth embodiment.
Third conductive underlying layer 33, fourth conductive underlying layer 34, and third insulating layer 35 in the third embodiment may be provided in chip resistor 1d in the fourth embodiment. The scope of the present disclosure is defined by the terms of the claims rather than the description above and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
1, 1b, 1c, 1d chip resistor; 5 resistive element frame; 10 resistive element; 10a band-shaped resistive element; 10m central portion; 11 first main surface; 12 second main surface; 13a first side surface; 13b second side surface; 14a third side surface; 14b fourth side surface; 15 first insulating layer; 15a first end; 15b second end; 16 second insulating layer; 16a third end; 16b fourth end; 17 first conductive underlying layer; 17a, 17b end; 18 second conductive underlying layer; 18a, 18b end; 20 first electrode; 21 first electrode layer; 21m first portion; 22 third electrode layer; 22m third portion; 23 first thin metal layer; 25 second electrode; 26 second electrode layer; 26m second portion; 27 fourth electrode layer; 27m fourth portion; 28 second thin metal layer; 30 insulating coating film; 33 third conductive underlying layer; 33a end; 34 fourth conductive underlying layer; 34a end; 35 third insulating layer; 40 first conductive film; 41 second conductive film; 50 circuit board; 51 insulating substrate; 52, 53 conductive wire; 54, 55 bonding member
Number | Date | Country | Kind |
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2020-183490 | Nov 2020 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2021/034732 | 9/22/2021 | WO |