JP2019016756A - Resistor - Google Patents

Abstract

To provide a resistor which enables the increase in long-term reliability even in such a condition that a high power is applied thereto.SOLUTION: A resistor 10 of the present invention comprises: a first resistor 11 including a metal; a pair of electrodes 12a and 12b formed on opposing end portions of a lower face of the first resistor 11; a first substrate 13 formed on an upper face of the first resistor 11; a first heat radiator plate 14 formed on an upper face of the first substrate 13, configured of a metal divided into more than one piece by a first gap 16 and connected to a pair of end face electrodes 15a and 15b; a second substrate 20 formed on an upper face of the first heat radiator plate 14; a second resistor 21 formed on an upper face of the second substrate 20, and including metal; and the pair of end face electrodes 15a and 15b formed on end faces of the first and second resistors 11 and 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a high-power and low-resistance resistor used for detecting a current value of various electronic devices.

  As shown in FIG. 2, this type of conventional resistor includes a resistor 1 made of a plate-like or foil-like metal and a pair of ends formed on both ends of the first surface of the resistor 1. It was formed on the upper surface of the heat sink 4 between the pair of electrodes 2 and the heat radiation plate 4 with good heat conduction, which was bonded to the second surface of the electrode 2 and the resistor 1 via the insulating adhesive 3. The heat sink 4 was divided into two by the gap 6.

  As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.

JP 2010-514171 A

  In the above conventional resistor, the heat generated in the resistor 1 is not easily conducted to the heat sink 4 by the insulating adhesive 3 between the heat sink 4 and the resistor 1, so that the temperature of the resistor 1 is increased. There was a problem that the state became high and long-term reliability deteriorated.

  In particular, since the resistor 1 is formed only on one side of the heat radiating plate 4, when the high electric power is applied, the resistor 1 generates a large amount of heat, and the temperature of the resistor 1 becomes very high.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a resistor capable of improving long-term reliability even when high power is applied.

  A resistor according to a first aspect includes a first resistor made of metal, a pair of electrodes formed at both ends of the lower surface of the first resistor, and an upper surface of the first resistor. A first substrate formed on the first resistor, a pair of end surface electrodes connected to both end surfaces of the first resistor, and formed on the upper surface of the first substrate, and divided into a plurality through a first gap. A first heat dissipating plate that is made of the formed metal and connected to the pair of end surface electrodes, a second substrate formed above the first heat dissipating plate, and an upper surface of the second substrate And a second resistor formed of metal and connected to the pair of end surface electrodes.

  In the resistor according to the second aspect, in the first aspect, the resistance value of the first resistor is made lower than the resistance value of the second resistor.

  In the resistor according to the third aspect, in the first aspect, the first substrate is made of a resin containing alumina powder or silica powder.

  In the resistor according to the fourth aspect, in the first aspect, the second substrate is made of the same material as the mounting substrate.

  In the resistor according to the fifth aspect, in the first aspect, a third substrate and a second heat sink are arranged in order from the bottom between the second substrate and the first heat sink, and the second The heat radiating plate was made of a metal divided into a plurality of parts through the second gap, and connected to the pair of end face electrodes.

  Long-term reliability can be improved even when high power is applied.

Sectional drawing of the resistor in one embodiment of this invention Cross section of conventional resistor

  FIG. 1 is a cross-sectional view of a resistor 10 according to an embodiment of the present invention.

  As shown in FIG. 1, a resistor 10 according to an embodiment of the present invention includes a first resistor 11 made of metal and a pair of ends formed on both ends of the lower surface of the first resistor 11. The electrodes 12 a and 12 b, the first substrate 13 formed on the upper surface of the first resistor 11, the first heat radiation plate 14 formed on the upper surface of the first substrate 13, and the first resistor 11 And a pair of end surface electrodes 15a and 15b formed on both end surfaces.

  Further, the first heat radiating plate 14 is made of a metal divided into two first heat radiating plates 14a and 14b with a first gap 16 therebetween, and each is connected to a pair of end surface electrodes 15a and 15b. ing.

  Further, a third substrate 17 and a second radiator plate 18 formed on the upper surface of the third substrate 17 are further formed on the upper surfaces of the first radiator plates 14a and 14b. The metal is divided into two second heat radiation plates 18a and 18b through the second gap 19, and is connected to the pair of end surface electrodes 15a and 15b, respectively.

  Further, a second substrate 20 is formed on the upper surface of the second heat radiating plate 18, and a second resistor 21 is formed on the upper surface of the second substrate 20. Further, the second resistor 21 is connected to the pair of end surface electrodes 15a and 15b, and the protective film 22 is formed on the upper surface thereof.

  In the above configuration, the first resistor 11 and the second resistor 21 are made of plate-like or foil-like CuMnNi (manganin). Other metal materials such as CuNi, CuMn, NiCr, CuNiSn may be used, but CuMnNi having a low TCR is more preferable.

  The first resistor 11 and the second resistor 21 are formed in a meandering manner by etching or the like, and further provided with one or a plurality of trimming grooves (not shown), whereby the resistance value is adjusted. .

  Further, the pair of electrodes 12 a and 12 b are formed at both ends of the lower surface of the first resistor 11. The pair of electrodes 12a and 12b is formed by directly plating a metal material mainly composed of Cu. A separate metal plate may be formed by welding and clad joining to the first resistor 11 or by sputtering or printing on the first resistor 11.

  Further, on the lower surface of the first resistor 11, a protective film 23 made of an epoxy resin or a silicon resin is provided between the pair of electrodes 12a and 12b.

  The pair of electrodes 12a and 12b is connected to a mounting substrate (hereinafter not shown), and the resistor 10 is mounted.

  The first substrate 13 is a high thermal conductive resin substrate that is formed so as to be in direct contact with the upper surface of the first resistor 11, and is composed of epoxy resin mixed with alumina powder.

  The first substrate 13 has good thermal conductivity due to alumina powder, and further has insulating properties. Moreover, since it contains resin, the adhesiveness with the 1st resistor 11 and the 1st heat sink 14 becomes favorable by pressing, and an adhesive agent becomes unnecessary. That is, by using the first substrate 13, both thermal conductivity and adhesiveness can be satisfied.

  Here, the content of the alumina powder contained in the first substrate 13 is preferably 30 vol% to 60 vol%. When the content of alumina powder is small, the thermal conductivity is deteriorated. If the content of the alumina powder is large, the adhesiveness is deteriorated.

  In addition, although silica powder may be used instead of alumina powder, alumina powder having a higher thermal conductivity is more preferable.

  The thickness of the first substrate 13 is thicker than that of the first and second radiator plates 14 and 18.

  Further, the first heat radiating plate 14 is directly formed at both ends of the upper surface of the first substrate 13 and is divided into two first heat radiating plates 14 a and 14 b through a first gap 16.

  The first heat radiating plate 14 is made of a metal such as Cu, and one of the first heat radiating plates 14a is one of the pair of end surface electrodes 15a and 15b and the other first heat radiating plate. 14b is connected to the other of the pair of end face electrodes 15a and 15b.

  Further, the pair of end surface electrodes 15 a and 15 b are composed of the first resistor 11, the pair of electrodes 12 a and 12 b, the first substrate 13, the first heat radiating plate 14, the second substrate 20, and the second heat radiating plate 18. , Formed on both ends of the third substrate 17 and the second resistor 21 and provided by sputtering copper or nichrome.

  Further, nickel plating and tin plating are formed on the surface. In mounting, solder plating for mounting is formed on the surface.

  The third substrate 17 is provided on the upper surfaces of the first heat radiation plates 14a and 14b, and is made of the same glass epoxy as the material used for the mounting substrate.

  The second heat radiating plate 18 is formed at both ends of the upper surface of the third substrate 17, and is divided into two second heat radiating plates 18 a and 18 b through a second gap 19.

  The second heat radiating plate 18 is made of a metal such as Cu, and one of the second heat radiating plates 18a is one of the pair of end surface electrodes 15a and 15b and the other second heat radiating plate. 18b is connected to the other of the pair of end face electrodes 15a and 15b.

  The first heat radiating plate 14 and the second heat radiating plate 18 are formed by attaching a plate made of a metal such as Cu to the first substrate 13, the second substrate 20, and the third substrate 17.

In addition, by forming the first gap 16 and the second gap 19 in the first heat sink 14 and the second heat sink 18, current is supplied to the first heat sink 14 and the second heat sink 18. The route is made impossible.

  Accordingly, the dimensions of the first gap 16 and the second gap 19 are preferably 1/50 or more with respect to the total length of the resistor 10 (the length of the first substrate 13 and the second substrate 20). . On the other hand, if it exceeds 1/10, the lengths of the first heat radiating plate 14 and the second heat radiating plate 18 are shortened and the heat radiating effect is decreased, which is not preferable.

  Further, the second substrate 20 is formed on the upper surface of the second heat radiating plate 18 and is made of the same glass epoxy as the material used for the mounting substrate.

  A second resistor 21 is formed on the upper surface of the second substrate 20. Further, the second resistor 21 is connected to the pair of end surface electrodes 15a and 15b, and the protective film 22 is formed on the upper surface thereof.

  A plurality of combinations of the third substrate 17 and the second heat radiating plates 18 located at both ends of the upper surface of the third substrate 17 may be stacked.

  Here, the first resistor 11 and the second resistor 21 are provided above and below the resistor 10 and are connected in parallel via a pair of end surface electrodes 15a and 15b. Is a combined resistance value of the resistance value of the first resistor 11 and the resistance value of the second resistor 21.

  Between the pair of electrodes 12 a and 12 b, the resistance values of the first resistor 11 and the second resistor 21 may be substantially the same, but the resistance value of the first resistor 11 is higher than that of the second resistor 21. Is more preferable. At this time, the current is shunted to the first resistor 11 and the second resistor 21, and more flows to the first resistor 11 having a lower resistance value than the second resistor 21.

  Since a large amount of current flows through the first resistor 11 closer to the mounting substrate, the heat generated by the first resistor 11 is easily dissipated to the mounting substrate. The resistance value of the first resistor 11 is preferably 1/3 to 1/10 of the resistance value of the second resistor 21. There is little electric current which flows into the 2nd resistor 21, and the emitted-heat amount is small.

  Thus, since the first resistor 11 generates higher heat than the second resistor 21, the first resistor 11 having good heat dissipation efficiency to the mounting substrate is used as the mounting surface.

  In other words, the lower one of the first resistor 11 and the second resistor 21 is provided on the lower side so as to be close to the mounting substrate.

  In this specification, the side where the mounting substrate is located is the lower side.

  In the resistor 10, the heat generated in the first and second resistors 11 and 21 when a current is applied passes through the first substrate 13, the second substrate 20, and the third substrate 17. The heat transferred to the first heat sink 14 and the second heat sink 18 and transferred to the first heat sink 14 and the second heat sink 18 is dissipated to the mounting substrate through the pair of end face electrodes 15a and 15b. In addition, heat is radiated to the mounting substrate through the pair of electrodes 12a and 12b, whereby the temperature of the first and second resistors 11 and 21 can be lowered.

  Next, a method for manufacturing the resistor 10 according to the embodiment of the present invention will be described with reference to FIG.

First, the 1st heat sink 14 and the 2nd heat sink 18 are adhere | attached on the both ends of the both surfaces of the 3rd board | substrate 17 by thermocompression bonding. At this time, the first gap 16 and the second gap 19 are formed by etching.

  Next, the second substrate 20, the first substrate 13, the first resistor 11, and the second resistor 21 are attached and pressed. Thereby, the 1st board | substrate 13, the 1st resistor 11, and the 1st heat sink 14 can be adhere | attached, the 2nd board | substrate 20, the 2nd resistor 21, and the 2nd heat sink 18 can be adhered.

  At this time, the second substrate 20 and the first substrate 13 fill the first gap 16 and the second gap 19.

  Next, after making the first and second resistors 11 and 21 meander by etching, a pair of electrodes 12 a and 12 b are formed by plating on both ends of the lower surface of the first resistor 11.

  Next, a trimming groove (not shown) is formed in the first and second resistors 11 and 21, thereby adjusting the resistance value.

  Next, an epoxy resin or a silicon resin is applied between the pair of electrodes 12 a and 12 b on the lower surface of the first resistor 11 and dried to form the protective film 23.

  Further, an epoxy resin or a silicon resin is applied to the upper surface of the second resistor 21 and dried to form the protective film 22.

  Finally, the first and second resistors 11 and 21, the pair of electrodes 12a and 12b, both ends of the first, second, and third substrates 13, 17, and 20, and the first and second heat sinks 14 and 18 are sputtered with copper or nichrome to form a pair of end face electrodes 15a and 15b, and then nickel plating and tin plating are formed on the surfaces thereof.

  In the resistor according to the embodiment of the present invention, since the first resistor 11 and the second resistor 21 are connected in parallel, the first and second resistors are applied even when high power is applied. 11 and 21 generate less heat, and the temperature of the first and second resistors 11 and 21 can thereby be lowered. Therefore, high rated power and long-term reliability can be improved.

  Further, the first substrate 13 is made of an epoxy resin mixed with alumina powder, and the first substrate 13 and the first resistor 11 through which a large amount of current flows are in direct contact with each other. 13 and the heat radiating plate 14 are in direct contact, heat generated in the first resistor 11 can easily escape to the mounting substrate via the heat radiating plate 14, and thereby the temperature of the first resistor 11 can be reduced. Can be greatly reduced, and long-term reliability can be improved.

  That is, when the resistor and the heat sink are bonded with an adhesive as in the conventional case, the heat generated in the resistor is difficult to conduct to the heat sink, and if the adhesive is thinned to improve heat conduction, Insulation cannot be maintained.

  On the other hand, in one embodiment of the present invention, a highly thermally conductive resin substrate (a mixture of epoxy resin and alumina powder) between the first resistor 11 and the first heat radiating plate 14 ( Since the first substrate 13 is formed, as described above, it has good thermal conductivity, insulation, and good adhesion to the first resistor 11 and the first heat sink 14. It has become.

As the first substrate 13, ceramic that requires an adhesive cannot be used. Even if the thickness of the first substrate 13 is increased in order to improve insulation, the thermal conductivity is maintained. However, if the thickness of the adhesive is increased, the thermal conductivity deteriorates.

  Moreover, since it has the 2nd, 3rd board | substrates 17 and 20 comprised with the glass epoxy which is a material used for the board | substrate for mounting, the solder crack by the difference in the thermal expansion coefficient after mounting can be prevented. . Furthermore, it is excellent in heat resistance.

  That is, a high thermal conductive resin substrate (first substrate) 13 composed of a mixture of epoxy resin and alumina powder, and a resin substrate composed of glass epoxy (second substrate 20 and third substrate 17). ) Can be improved in long-term reliability, higher rated power, prevention of solder cracks, and heat resistance.

  Since the second resistor 21 and the second substrate 20 are made of glass epoxy as described above, the adhesion is improved by pressing both. Note that the second substrate 20 may be composed of an epoxy resin mixed with alumina powder, similar to the first substrate 13.

  Since the upper and lower sides of the resistor 10 are sandwiched between the first resistor 11 and the second resistor 21, the weight balance is improved.

  In FIG. 1, the first gap 16 and the second gap 19 are at the same position when viewed from the top, but if they are provided at different positions when viewed from the top, the product strength can be improved. At this time, if it is arranged in line symmetry with respect to the center line in the longitudinal direction of the resistor when viewed from above, the central part that is most easily deformed by stress can be reinforced efficiently.

  Furthermore, you may divide | segment the 1st heat sink 14 and the 2nd heat sink 18 into three or more instead of two. At this time, the first heat radiating plate 14 and the second heat radiating plate 18 are always connected to both the pair of end surface electrodes 15a and 15b.

  And you may comprise the 1st heat sink 14 and the 2nd heat sink 18 with one metal.

  At this time, one end of the first heat radiating plate 14 is connected to one of the pair of end surface electrodes 15a and 15b, and one end of the second heat radiating plate 18 is connected to the other of the pair of end surface electrodes 15a and 15b.

  With this configuration, the lengths of the first and second heat sinks 14 and 18 covering the first and second resistors 11 and 21 are increased. The generated heat can be effectively released.

  In addition, it is preferable to mix the filler comprised with ceramic powders, such as a silica and an alumina, in the protective films 22 and 23. FIG. Since the heat generated in the first and second resistors 11 and 21 can be released to the protective films 22 and 23 as well, the temperature of the first and second resistors 11 and 21 can be further lowered. It is.

  The resistor according to the present invention has an effect that long-term reliability can be improved even when high power is applied, and is particularly high power and low resistance used for current value detection of various electronic devices. It is useful when applied to a value resistor or the like.

DESCRIPTION OF SYMBOLS 11 1st resistor 12a, 12b A pair of electrode 13 1st board | substrate 14 (14a, 14b) 1st heat sink 15a, 15b A pair of end surface electrode 16 1st clearance gap 17 3rd board | substrate 18 (18a, 18b) ) 2nd heat sink 19 2nd gap 20 2nd board | substrate 21 2nd resistor

Claims (5)

A first resistor made of metal; a pair of electrodes formed on both ends of the lower surface of the first resistor; a first substrate formed on the upper surface of the first resistor; A pair of end face electrodes connected to both end faces of the first resistor, and a metal formed on the top surface of the first substrate and divided into a plurality of parts through a first gap, and the pair A first heat dissipating plate connected to the end face electrode, a second substrate formed above the first heat dissipating plate, an upper surface of the second substrate, made of metal, and And a second resistor connected to the pair of end surface electrodes. The resistor according to claim 1, wherein a resistance value of the first resistor is lower than a resistance value of the second resistor. The resistor according to claim 1, wherein the first substrate is made of a resin containing alumina powder or silica powder. The resistor according to claim 1, wherein the second substrate is made of the same material as the mounting substrate. Between the second substrate and the first heat radiating plate, a third substrate and a second heat radiating plate are arranged in order from the bottom, and the second heat radiating plate is divided into a plurality through a second gap. The resistor according to claim 1, wherein the resistor is made of a metal and connected to the pair of end face electrodes.