JP2009218317A - Surface-mounted resistor, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounted current-detecting resistor capable of providing an excellent resistance temperature coefficient (T. C. R), by reducing surplus resistance while keeping an excellent heat dissipation property, and to provide its manufacturing method. <P>SOLUTION: This surface mounted current-detecting resistor is provided with: a resistance layer 11 formed of a resistance alloy material; an insulation resin layer 12; a pair of plate body-like undersurface electrodes 13; an undersurface insulation resin material 14 connecting the pair of undersurface electrodes to each other; a pair of upper-surface electrodes 15 fixed to upper surfaces at both ends of the resistance layer; an upper-surface insulation resin material 16 connecting the pair of upper-surface electrodes to each other; and plated layers 18 connecting the upper-surface electrodes to the undersurface electrodes. The undersurface electrode 13 is divided into an inner electrode 13a and an outer electrode 13b along the longitudinal direction of the resistor through the undersurface insulation resin material; recessed parts 17 are formed on side surfaces of the resistance layer and the upper electrodes; and the inner electrodes and the outer electrodes are respectively connected to the upper-surface electrodes by the plated layers divided by the resistance layer and the upper-surface insulation resin material filled in the recessed parts of the side surfaces of the upper-surface electrodes. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention has a plate-like electrode made of a highly conductive metal material such as copper at both ends of a plate-like resistor made of a resistance alloy material such as a copper-nickel alloy, and detects a large current with high accuracy. The present invention relates to a surface mount type resistor for current detection.

  As an example of the current detection resistor, a resistor described in Patent Document 1 is known. This resistor is provided with a resistance film (15) made of a resistance alloy material as a resistance path via an insulating layer (18) on two electrically separated copper support plate elements (10A, 10B), Both ends of the resistance film (15) are connected to the support plate elements (10A, 10B) by the metal layer (16). It is described that the support plate elements (10A, 10B) are configured as contact elements that can be soldered to the terminals of the printed circuit board, thereby improving heat dissipation to the printed circuit board.

However, in the resistor, the current to be measured is supplied to the resistor and the voltage generated at both ends of the resistor is detected by the terminals of the printed circuit board soldered to the support plate elements (10A, 10B). . For this reason, since the detected voltage is obtained by connecting both ends of the resistance film (15) to the support plate elements (10A, 10B) by the metal layer (16), the metal layer having a high resistance temperature coefficient (TCR) ( 16) and the influence of surplus resistance by the support plate elements (10A, 10B), there is a problem that the temperature coefficient of resistance (TCR) of the entire resistor is deteriorated. In ordinary resistors, the resistance value is relatively high, and therefore the influence of these surplus resistances hardly occurs. However, in the current detection resistor having a resistance value of the order of mΩ, the surplus resistance portion is, for example, When copper is used, the temperature coefficient of resistance (TCR) is about 3000 ppm / K, which causes the above problem.
JP-A-7-192902

  The present invention has been made based on the above-described circumstances, and reduces the excess resistance while maintaining good heat dissipation, and a surface-mounted current detection resistor capable of obtaining a good resistance temperature coefficient (TCR) and its An object is to provide a manufacturing method.

  The surface-mounted resistor according to the present invention includes a resistance layer made of a resistance alloy material, an insulating resin layer fixed to the lower surface of the resistance layer, and a plate-like highly conductive material fixed to the lower surface of the insulating resin layer. A pair of lower surface electrodes made of a conductive metal material, a lower surface insulating resin material connecting the pair of lower surface electrodes to each other, and a pair of upper surface electrodes made of a highly conductive metal material fixed to the upper surfaces of both end portions of the resistance layer; An upper surface insulating resin material for connecting the pair of electrodes to each other; and a plating layer for connecting the upper surface electrode and the lower surface electrode. The lower surface electrode includes an inner electrode and an outer electrode along the longitudinal direction of the resistor. The resistance layer and the top electrode are provided with a recess on the side surface, the recess is filled with the top insulation resin material, and each of the inner electrode and the outer electrode is Top surface insulation filled in the recesses on the sides of the resistance layer and top electrode By the plating layers separated by fat material, characterized in that it is connected to the upper electrode.

  The method for manufacturing a surface-mounted resistor according to the present invention includes forming a clad material obtained by joining a foil material made of a highly conductive metal material and a foil material made of a resistance alloy material, and forming a resistance path on the clad material. Forming a pattern, an upper electrode pattern on both ends thereof, and a recess on a side surface of the upper electrode pattern, and bonding the clad material to a plate made of a highly conductive metal material via an insulating resin layer; The foil material made of the highly conductive metal material in the resistance path pattern portion of the material is removed by etching to separate and form upper surface electrodes at both ends of the clad material, and the plate made of the highly conductive metal material is formed. Separated by etching to form a bottom electrode composed of an inner electrode and an outer electrode along the longitudinal direction of the resistor, between the inner electrode and the outer electrode of the lower electrode, between the pair of inner electrodes, and the upper electrode Between, and An insulative resin material is filled in the concave portion on the side surface of the surface electrode pattern, and the electrodes are insulated and connected, and a plating layer is formed to connect the inner electrode and the outer electrode to the upper electrode, respectively. It is characterized by that. Here, the plating layer is formed as an integral plating layer by joining a plating layer extending from the upper electrode side and a plating layer extending from the lower electrode side.

According to the surface mount type resistor of the present invention, the upper surface insulating resin in which the inner electrode is insulated and separated by the outer electrode and the lower surface insulating resin material, and the plating layer on the side surface of the resistor is filled in the concave portion on the side surface of the upper surface electrode and the resistance layer. Since it is insulated and separated by the material and connected to the upper surface electrode, it is possible to directly detect the voltage corresponding to the current to be measured generated at both ends of the resistance path by the inner electrode. As a result, surplus resistance generated between the outer electrode and both ends of the resistance path is not included in the voltage detection path, and accurate voltage detection of the current to be measured can be performed.
According to the method for manufacturing a surface-mounted resistor of the present invention, a highly accurate surface-mounted current detecting resistor can be easily connected by connecting the inner electrode and the outer electrode of the upper surface electrode and the lower surface electrode with a plating layer. Can be manufactured.

  Embodiments of a surface-mounted resistor and a method for manufacturing the same according to the present invention will be described below with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected and demonstrated to the same or equivalent member or element.

  This surface-mounted resistor 10 includes a longitudinal sectional view in the longitudinal direction of FIG. 1A (a sectional view taken along the line AA in FIG. 1D) and a sectional view of the resistive layer surface in FIG. As shown in (c) BB cross-sectional view), a foil-like resistance layer 11 made of a resistance alloy material having a low resistivity and a good temperature coefficient of resistance (TCR) such as copper nickel, nichrome, manganin, iron chrome, etc. An insulating resin layer 12 is fixed to the lower surface, and a pair of lower surface electrodes 13 and 13 made of a highly conductive metal material such as plate-like copper are fixed to the lower surface of the insulating resin layer 12. The lower surface electrodes 13 and 13 are separated via a central lower surface insulating resin material 14a, and each of the lower surface electrodes 13 and 13 is disposed on the inner side and the outer side on the inner side along the longitudinal direction of the resistor. The outer electrode 13b is insulated and separated through the lower surface insulating resin material 14b.

  A pair of upper surface electrodes 15, 15 made of a highly conductive metal material such as copper is fixed to the upper surface of both end portions of the foil-like resistance layer 11, and a pair of upper surface electrodes 15 b made of a highly conductive metal material such as copper are fixed to the upper surface of the resistance path portion 11 b of the foil-like resistance layer 11. An upper surface insulating resin material 16 that connects the upper surface electrodes 15 and 15 while being insulated and separated from each other is disposed. As shown in FIG. 1B, the resistance layer 11 is composed of an electrode portion 11a at both ends and a resistance path portion 11b between them, and is a single resistor plate. Upper surface electrodes 15 and 15 are fixed to the upper surfaces of the electrode portions 11a and 11a at both ends, and the resistance path portion 11b has a resistance path pattern corresponding to a required resistance value as shown in the figure, for example. The upper surface insulating resin material 16 is filled in a portion where the road pattern does not exist. Further, concave portions 17 are provided on both side surfaces of the electrode portions 11a and 11a at both ends of the resistance layer 11, and the upper surface insulating resin material 16 is filled therewith. As shown in the longitudinal side cross-sectional view in FIG. 1 (c) (CC cross-sectional view in FIG. 1 (d)), the top electrodes 15 and 15 are also provided with a recess 17 at the same position as the resistive layer 11, The upper surface insulating resin material 16 is filled.

  Accordingly, as shown in FIGS. 1B and 1C, the electrode portion 11a and the upper surface electrode 15 of the resistance layer 11 are provided with the concave portion 17 filled with the upper surface insulating resin material on the resistor side surface, and these side surfaces are provided. As shown in FIG. 1E, the plating layers 18a and 18b are insulated and separated. On the other hand, between the inner electrode 13a and the outer electrode 13b of the lower surface electrode, the lower surface insulating resin material 14b is filled in the entire width in the width direction of the resistor and is completely insulated and separated.

  As shown in FIGS. 1D, 1E, and 1F, in this resistor 10, all exposed surfaces of the lower surface electrode 13, the resistance layer electrode portion 11a, and the upper surface electrode 15 are covered with the plating layer 18. Yes. The plating layer 18 is composed of three plating layers of Cu, Ni, and Sn. Here, the plating layers 18a and 18b are insulated and separated by the lower surface insulating resin material 14b and the insulating resin material 16 filled in the recess 17, and the inner electrode 13a of the lower surface electrode 13 is connected to the upper surface electrode 15 by the side plating layer 18a. Then, the outer electrode 13b of the lower electrode 13 is connected to the upper electrode 15 by the plating layer 18b on the side surface and the end surface.

  At the time of mounting, as shown in FIG. 2A, a current terminal pad 21 and a voltage terminal pad 22 which are wiring pads are prepared on a mounting board such as a printed board, and a surface mount type resistor is provided on the current terminal pad 21. 10 outer electrodes 13 b are connected, and the inner electrode 13 a is connected to the voltage terminal pad 22. The current terminal pad 21 includes a wiring terminal 21a connected to the supply source of the current to be measured, and the voltage terminal pad 22 includes a wiring terminal 22a connected to the detection voltage measuring device. Therefore, as shown in FIG. 2B, the surface mount type resistor 10 is mounted on the mounting substrate 20.

  In the mounted state, the current to be measured flows from one current terminal pad 21 into the outer electrode 13 b of the resistor 10, and flows into one of the resistance layers 11 through the plating layer 18 a and the upper surface electrode 15 on the end surface and side surface. The current to be measured flowing out from the other side of the resistance layer 11 passes through the upper surface electrode 15, the end surface and the side plating layer 18 a, and the outer electrode 13 b, and then flows out to the other current terminal pad 21. In this current path, a voltage corresponding to the product of the resistance value of the resistance path portion 11b of the resistance layer 11 and the current is generated at both ends of the resistance path portion 11b, and this voltage is used as a detection voltage to detect the top electrode 15 and the plating layer 18b. It can be detected from the wiring terminal 22b of the voltage terminal pad 22 through the inner electrode 13a.

  Therefore, in the surface-mounted resistor 10 of the present invention, the current to be measured flows from the current terminal pad 21, the outer electrode 13b, the plating layer 18a, and the upper surface electrode 15 to the resistance layer 11, and the resistance of this portion becomes an excess resistance. However, no current to be measured flows through the voltage detection path constituted by the plating layer 18b and the inner electrode 13b. For this reason, from the voltage detection path arranged at both ends of the resistance path portion 11b composed of the inner electrode 13a, the plating layer 18b, and the upper surface electrode 15, it corresponds to the product of the current to be measured and the resistance value of the resistance path portion 11b. Only the voltage is detected, the voltage corresponding to the surplus resistance is not included, and accurate voltage detection of the current to be measured can be performed.

  As an example, a simulation result of a surface-mount resistor having a size of 6.3 mm long × 3.2 mm wide will be described. The simulation was performed by setting the Cu thickness of the plating layer to 0.05 mm, the resistance temperature coefficient (T.C.R.) to 3000 ppm / K, and ignoring others. As a result, the conventional structure has a resistance temperature coefficient (TCR) of 39 ppm / K at a resistance value of 8.60 mΩ at 25 ° C., whereas the resistance temperature coefficient (TCR) at a resistance value of 25 ° C. of 8.52 mΩ in the structure of the present invention. ) A result of 11 ppm / K was obtained, confirming the effectiveness of the structure of the present invention. Note that as the size of the surface-mounted resistor is further reduced, the effect is considered to be more prominent because the influence of the plating layer is increased.

  Next, an example of a method for manufacturing the surface-mounted resistor according to the present invention will be described. First, as shown in FIG. 3A, a Cu foil material 15 m having a thickness of 20 to 100 μm and a Ni—Cr alloy foil material 11 m having a thickness of 40 to 100 μm are pressed to form a clad material 30. To do. In the figure, the left column is a sectional view of one product, the middle column is a plan view of one product, and the right column is a plan view of a multi-sheet.

  Next, as shown in FIG. 3B, the resistance path pattern 11b, the upper surface electrode pattern 11a at both ends thereof, and the recesses 17 and the like are formed on the side surfaces of the upper surface electrode pattern by double-sided photoetching on the clad material 30. . One section surrounded by a dotted line in the sheet on the right column corresponds to one product in the middle column. Next, as shown in FIG. 3C, a Cu base material 13m having a thickness of about 200 μm is bonded to the patterned clad material 30 using an epoxy adhesive 12m. Thereby, the insulating resin layer 12m to which the clad material 30 and the Cu base material 13m are fixed is formed. The insulating resin layer 12m is formed to a thickness of about 40 to 100 μm.

  Next, by removing the Cu foil material on the resistance path portion 11b of the resistance layer 11 by etching, the resistance path portion 11b is exposed and the upper surface electrodes 15 and 15 are formed separately. At this time, the resistance value may be trimmed by adjusting the thickness of the resistance path portion 11b by polishing.

  Next, as shown in FIG. 4 (a), the Cu base material 13m on the back surface side is etched so as to reach the insulating resin layer 12, and the inner electrode 13a and the outer electrode 13b of the lower surface electrode 13 are insulated and separated. To form. Then, as shown in FIG. 4B, the bottom insulating resin material paste 14a is formed between the inner electrodes by filling the etching-treated space with the bottom insulating resin material paste by screen printing and heating and curing. The lower surface insulating resin material 14b is formed between the inner electrode and the outer electrode.

  Next, as shown in FIG. 4 (c), the upper surface insulating resin material paste is completely covered with the resistance path 11b and embedded in the recesses 17 by screen printing on the surface side, and is heated and cured. Then, the upper surface insulating resin material 16 is formed on each. And as shown in FIG.4 (d), the surface mount type resistor corresponding to each product is obtained by dividing | segmenting or cut | disconnecting by the cutting line S. FIG. Note that the marking or the like may be performed after being divided into individual products or at the stage of multi-sheets.

  Next, formation of the plating layer will be described with reference to FIG. The plating layer 18 is formed by electrolytic plating as a plating layer of three layers of Cu, Ni, and Sn. Here, if the Cu plating layer is at least half the thickness of the insulating resin layer 12, the plating layer extending from the upper surface electrode side and the plating layer extending from the lower surface electrode side are joined to form an integrated plating layer 18.

  That is, the stage shown in FIG. 5A is the stage where the multi-sheet is cut and divided into individual products in FIG. 4D. At this stage, if the plating process is performed a little, the surface of the insulating resin layer 12 that is an insulator is not plated, but the resistance layer 11 made of a resistance alloy, the lower electrode 13 made of Cu, and the upper electrode 15 are plated. Adheres (see FIG. 5B). Furthermore, as the plating thickness increases, the exposed area of the insulating resin layer gradually decreases (see FIG. 5C). Then, when the thickness of the Cu plating layer becomes more than half of the thickness of the insulating resin layer 12, the plating layer extending from the upper surface electrode 15 side and the plating layer extending from the lower surface electrode 13 side are joined, and the integrated plating layer 18 is joined. (See FIG. 5D). By this plating layer formation, the surface mount type resistor of the present invention is completed.

  Therefore, according to the manufacturing process of the above surface mount type resistor, the plating layer that easily crosses the insulating resin layer by making the plating layer connecting the upper surface electrode and the lower surface electrode more than half the thickness of the insulating resin layer. Thus, it is possible to provide a surface mount type resistor that can obtain a low temperature coefficient of resistance (TCR) while simplifying the process.

  Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea.

(A) is the center part sectional drawing (AA sectional view of FIG.1 (d)) which shows the surface mounted resistor of one Embodiment of this invention in the longitudinal direction, (b) is sectional drawing of a resistance layer surface FIG. 1C is a cross-sectional view taken along the line BB in FIG. 1C, FIG. 1C is a cross-sectional view taken along the side surface in the longitudinal direction of the surface-mounted resistor, and FIG. It is a top view of a surface-mounted resistor, (e) is a side view of the surface-mounted resistor, and (f) is a bottom view of the surface-mounted resistor. It is a figure which shows the mounting state, (a) is a top view which shows a current terminal pad and a voltage terminal pad, (b) is a side view of the surface mounted resistor of a mounting state. It is a figure which shows the manufacturing method of the surface mount-type resistor of this invention, The left column of a figure is sectional drawing for one product, A middle column is a top view for one product, A right column is many pieces It is a top view of a taking sheet. Similarly, it is a figure which shows the manufacturing method of the surface mount-type resistor of this invention, The left column of a figure is sectional drawing for one product, A middle column is a top view for one product, A right column is a figure. It is a top view of a multi-sheet. It is explanatory drawing of the step of the plating.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Surface mount type resistor 11 Resistance layer 12 Insulating resin layer 13 Lower surface electrode 13a Inner electrode 13b Outer electrode 14a, 14b Lower surface insulating resin layer 15 Upper surface electrode 16 Upper surface insulating resin layer 17 Recess 18, 18a, 18b Plating layer 20 Mounting substrate 21 Current supply terminal 22 Voltage detection terminal

Claims (7)

A resistance layer made of a resistance alloy material;
An insulating resin layer fixed to the lower surface of the resistance layer;
A pair of lower surface electrodes made of a plate-like highly conductive metal material fixed to the lower surface of the insulating resin layer, and a lower surface insulating resin material for connecting the pair of lower surface electrodes to each other;
A pair of upper surface electrodes made of a highly conductive metal material fixed to the upper surfaces of both end portions of the resistance layer; and an upper surface insulating resin material for connecting the pair of electrodes to each other;
A plating layer connecting the upper surface electrode and the lower surface electrode;
The lower surface electrode is separated through the lower surface insulating resin material into the inner electrode and the outer electrode along the longitudinal direction of the resistor,
A side surface of the resistance layer and the upper surface electrode is provided with a recess, and the recess is filled with the upper surface insulating resin material,
Each of the inner electrode and the outer electrode is connected to the upper surface electrode by the plating layer separated by the upper surface insulating resin material filled in the concave portion on the side surface of the resistance layer and the upper surface electrode. Surface mount type resistors.   2. The surface mount resistor according to claim 1, wherein the highly conductive metal material is copper. 2. The surface-mount resistor according to claim 1, wherein the resistance alloy material is a copper / nickel alloy , a nickel / chromium alloy, a copper / manganese alloy, or an iron / chromium alloy. A clad material is formed by joining a foil material made of a highly conductive metal material and a foil material made of a resistance alloy material,
Forming a resistance path pattern on the clad material, an upper electrode pattern on both ends thereof, and a recess on a side surface of the upper electrode pattern;
The clad material is bonded to a plate made of a highly conductive metal material via an insulating resin layer,
The foil material made of the highly conductive metal material in the resistance path pattern portion of the cladding material is removed by etching to form upper surface electrodes separately at both ends of the cladding material,
The plate body made of the highly conductive metal material is separated by etching to form a bottom electrode made of an inner electrode and an outer electrode along the longitudinal direction of the resistor,
An insulating resin material is filled between the inner electrode and the outer electrode of the lower surface electrode, between the pair of inner electrodes, between the pair of upper surface electrodes, and the concave portion on the side surface of the upper surface electrode pattern. Insulate and connect,
A method of manufacturing a surface-mounted resistor, comprising forming a plating layer that connects the inner electrode and the outer electrode to the upper surface electrode, respectively.   5. The surface-mount resistor according to claim 4, wherein the plating layer is formed as an integral plating layer by joining a plating layer extending from the upper surface electrode side and a plating layer extending from the lower surface electrode side. Method.   5. The method of manufacturing a surface-mounted resistor according to claim 4, wherein the highly conductive metal material is copper.   5. The method of manufacturing a surface-mounted resistor according to claim 4, wherein the resistance alloy material is a copper / nickel alloy, a nickel / chromium alloy, a copper / manganese alloy, or an iron / chromium alloy.

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