JP2004022920A - Chip resistor having low resistance and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a chip resistor in which resistance is decreased by providing connecting terminal electrodes at both ends on the back surface of a metal plate resistor, and weight and a cost are reduced by lowering the height of the resistor. <P>SOLUTION: Recesses 13 and 14 are formed in the both ends on the back surface of the metal plate resistor 12, and the connecting terminal electrodes 17 and 18 are provided in the recesses. On the other hand, a part between the connecting terminal electrodes 17 and 18 is coated with an insulator 15 at least on the back surface 12b of the resistor 12. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a chip resistor having a low resistance value, for example, 1Ω or less, and a method of manufacturing the same.
[0002]
[Prior art]
Japanese Patent Laying-Open No. 2001-118701 as a prior art proposes a chip resistor 1 having a configuration as shown in FIG.
[0003]
That is, the chip resistor 1 according to the prior art has a structure in which the resistor 2 has a resistance higher than that of the base metal such as nickel with respect to the base metal having low resistance such as copper. A rectangular plate having a length L and a width W is formed on a metal plate having a thickness T0 of a metal such as an alloy obtained by adding a metal having By forming a recess 3 having a length L0 and a depth S by cutting, connection terminal electrodes 4 and 5 are formed on the right and left ends of the back surface of the resistor 2. It has a configuration.
[0004]
In addition, plating layers 6 and 7 are formed on the connection terminal electrodes 4 and 5 to facilitate soldering to a printed circuit board or the like.
[0005]
[Problems to be solved by the invention]
However, in the chip resistor 1 according to the prior art, a recess 3 having a length L and a depth S is formed by cutting in a middle portion of the back surface of the resistor 2 made of a metal plate. With this configuration, the connection terminal electrodes 4 and 5 are provided at the left and right ends of the back surface of the resistor 2, so that the resistance value between the connection terminal electrodes 4 and 5, that is, the chip resistance In addition to the specific resistance of the metal constituting the resistor 2 and the width W0 of the resistor 2, the resistance value of the resistor 1 is determined by the length of the resistor 2 at the concave portion 3 engraved on the back surface thereof. Is determined by the thickness L0 and the remaining thickness T after the recess 3 having the depth S is formed. Therefore, the length L0 of the recess 3 formed on the back surface of the resistor 2 is determined. With depth S , It will appear turned with rose resistance value in the chip resistor 1.
[0006]
Therefore, when the recess 3 is formed on the back surface of the resistor 2 by cutting, both the length L0 and the depth S of the recess 3 must be strictly defined. In other words, in other words, the machining accuracy of the dimension when the recess 3 is carved must be increased for both the length dimension L0 and the depth dimension S in the recess 3, and the resistance There is a problem that engraving the recess 3 with respect to 2 requires a great deal of trouble and greatly increases the cost.
[0007]
When soldering the printed board or the like to the depth dimension S in the recess 3, the molten solder exceeds the two connection terminal electrodes 4 and 5 and is applied to the portion of the resistor 2 between the two connection terminal electrodes 4 and 5. In order to prevent the resistance value from changing due to the contact rising to the point, the resistance value must be considerably increased, so that not only the overall height dimension of the chip resistor 1 is increased but also the weight is increased. There were also problems.
[0008]
An object of the present invention is to solve these problems.
[0009]
[Means for Solving the Problems]
To achieve this technical task, the chip resistor of the present invention is:
"A concave portion is provided at the left and right ends of the back surface of the resistor formed of a metal plate, and a connection terminal electrode made of a metal having a lower resistance than the resistor is provided in the concave portion. At least a portion between the connection terminal electrodes on the back surface was covered with an insulator. "
It is characterized by:
[0010]
Further, the production method of the present invention,
"The process of manufacturing a metal plate made of a number of resistors constituting one chip resistor arranged and integrated,
A step of covering at least the back surface of the material metal plate with an insulator,
Depressed grooves as recesses are formed in the right and left ends of each resistor on the back surface of the metal plate while cutting out portions of the insulator corresponding to the left and right ends of each resistor. The process of setting up,
Forming a metal plating layer as a connection terminal electrode with a metal having a lower resistance than the material metal plate on a portion in each of the concave grooves on the back surface of the material metal plate;
A step of dividing the material metal plate for each of the resistors;
Consists of "
It is characterized by:
[0011]
[Action and Effect of the Invention]
As described above, the concave portion is provided at the left and right ends of the back surface of the resistor formed of the metal plate, and a connection terminal electrode made of a metal having a lower resistance than the resistor is provided in the concave portion. Since the influence of the depth of the recess formed in the back surface of the resistor on the resistance value between the two connection terminals, that is, the resistance value of the chip resistor is eliminated or reduced, the formation of the recess is performed. It is only necessary to maintain the length dimension at high processing accuracy, and the number of steps required to form a recess in the resistor can be reduced.
[0012]
In addition, at least a portion between the two connection terminal electrodes on the back surface of the resistor is covered with an insulator, so that when soldering to a printed circuit board or the like, molten solder is applied to both connection terminal electrodes of the resistor. Since the insulator can prevent the contact between the portions, the height dimension of the chip resistor can be reduced by that much, and the weight can be reduced.
[0013]
In this case, as described in claim 2, the two connection terminal electrodes are configured so that their surfaces are substantially flush with the surface of the insulator, or are configured to protrude from the surface of the insulator. In addition, when soldering to a printed board or the like, the floating of the two connection terminal electrodes from the printed board can be reduced or eliminated, so that there is an advantage that the reliability and strength of soldering can be improved.
[0014]
In addition, by configuring the two connection terminal electrodes with a metal plating layer as described in claim 3, the height of the chip resistor can be reduced and the weight can be further reduced.
[0015]
Furthermore, according to the manufacturing method described in claim 4, a large number of the chip resistors having the above-described configuration can be manufactured from a single material metal plate, and in addition, the connection terminal electrode is provided in the recess. When forming the metal plating layer as, the insulator formed on the back surface of the material metal plate becomes a mask for forming the metal plating layer only in the recess, in other words, the material metal plate Without masking the back surface, a metal plating layer can be formed only in the recess using the insulator, and the plating process is simplified, so that the manufacturing cost can be significantly reduced. .
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
[0017]
In this figure, reference numeral 11 indicates a chip resistor according to the embodiment of the present invention.
[0018]
The chip resistor 11 includes a resistor 12 having a rectangular shape having a length L and a width W.
[0019]
The resistor 12 is formed of a metal having a low resistance (hereinafter referred to as a low-resistance metal) such as a copper-nickel alloy, a nickel-chromium alloy, or an iron-chromium alloy. It is made of a metal plate having a thickness T by a metal such as an alloy obtained by adding a metal having a higher resistance than the material metal (hereinafter, referred to as a high-resistance metal).
[0020]
Of the front and back surfaces 12a and 12b of the resistor 12, concave portions having the lengths L1 and L2 and the depth S from the both end surfaces 12c and 12d of the resistor 12 are formed on both ends of the back surface 12b. Places 13 and 14 are engraved.
[0021]
Both the front surface 12a and the back surface 12b of the resistor 12 are covered with insulators 15, 16 such as heat-resistant synthetic resin or glass.
[0022]
On the other hand, connection terminal electrodes 17 and 18 made of pure metal such as copper are formed as metal plating layers in the recesses 13 and 14 at both ends of the back surface 12b of the resistor 12.
[0023]
The thickness of the connection terminal electrodes 17 and 18 is set to a dimension such that the surface thereof is substantially flush with the surface of the insulator 16 covering the back surface 12b of the resistor 12, or protrudes beyond this. ing.
[0024]
Further, plating layers 19 and 20 made of tin or solder are formed on the surfaces of the connection terminal electrodes 17 and 18 in order to facilitate their soldering to a printed circuit board or the like.
[0025]
Furthermore, trimming grooves 21 are formed on the side surfaces of the chip resistor 11 as necessary, as indicated by a two-dot chain line, so that the resistance value of the chip resistor 11 becomes a predetermined value. Has been adjusted.
[0026]
In the chip resistor 11 having this configuration, the resistance value between the two connection terminal electrodes 17 and 18, that is, the resistance value of the chip resistor 11 is the specific resistance of the metal forming the resistor 12, , And the length L3 (L3 = L−L1 + L2) between the two connection terminal electrodes 17 and 18 of the resistor 12, so that the two concave portions are provided as in the prior art. The influence of the depth dimension S at the places 13 and 14 on the resistance value of the chip resistor 11 can be eliminated or reduced.
[0027]
Further, when the chip resistor 11 is soldered to a printed board or the like, the back surface 12b of the resistor 12 is covered by the fact that the molten solder contacts the portion of the resistor 12 between the two connection terminal electrodes 17 and 18. It can be reliably prevented by the insulator 16.
[0028]
The chip resistor 11 having this configuration can be manufactured through the following steps (1) to (7).
▲ 1 ▼. As shown in FIG. 7, a material metal plate A is manufactured by arranging and integrating a large number of resistors 12 constituting the one chip resistor 11. Reference numerals B1 and B2 are a vertical cutting line and a horizontal cutting line that partition the material metal plate A for each of the resistors 12.
▲ 2 ▼. As shown in FIG. 8, both the front surface A1 and the back surface A2 of the material metal plate A are covered with insulators 15, 16 such as heat-resistant synthetic resin or glass.
(3). As shown in FIGS. 9 and 10, a recess groove A3 for forming recesses 13 and 14 at both ends of the resistor 12 is formed on the back surface A2 of the material metal plate A by the cutting line in the vertical direction. The portions of the recesses 13 and 14 in the insulator 16 on the back surface A2 are formed by machining such as cutting or grinding, machining by laser beam irradiation, or coining so as to extend along B1. Is formed so as to remove the insulator 16.
[0029]
The depth dimension of the concave groove A3 engraved here is S, and the width dimension D of the concave groove A3 is changed to the length dimensions L1 and L2 of the recesses 13 and 14 as described later. When the material metal plate A is divided into each resistor 12 by cutting along the vertical cutting line B1 with a dicing cutter or the like, the cutting width dimension by the dicing cutter or the like, that is, a dimension obtained by adding a cutting margin. When setting or performing the above-mentioned division by shearing processing (shearing processing) described later, by setting the width dimension D to the sum of the L1 and L2, the width D between the concave grooves A3 is set. The size is set to the length L3 of both connection terminal electrodes 13 and 14 in the chip resistor 11, that is, the length L3 for obtaining a predetermined resistance value.
▲ 4 ▼. By plating the entire material metal plate A after engraving the concave groove A3, as shown in FIGS. 11 and 12, a metal plating layer A4 is formed on the portion inside each concave groove A3. Is formed, the metal plating layer A4 is used as the connection terminal electrodes 17 and 18.
▲ 5 ▼. By performing another plating process on the entire material metal plate A after the formation of the metal plating layer A4, as shown in FIGS. 11 and 12, the surface of the metal plating layer A4 is A plating layer A5 is formed, and this plating layer A5 is used as plating layers 19 and 20 for soldering.
▲ 6 ▼. Then, the material metal plate A is cut by a dicing cutter or the like along the cutting line B1 in the vertical direction and the cutting line B2 in the horizontal direction to divide each of the resistors 12.
[0030]
This division may be performed by shearing (shearing) instead of cutting with a dicing cutter or the like.
▲ 7 ▼. If necessary, a trimming groove 21 is engraved on the side surface by irradiating a laser beam or the like while measuring the resistance value between the two connection terminal electrodes 17, 18 so that the space between the two connection terminal electrodes 17, 18 is formed. Is adjusted so that the resistance value at is set to a predetermined value.
[0031]
Through these steps, a large number of chip resistors 11 having the configuration shown in FIGS. 2 to 6 can be manufactured from one material metal plate A.
[0032]
In this manufacturing, the insulators 15 and 16 that cover the front and back surfaces A1 and A2 of the material metal plate A form the connection terminal electrodes 17 and 18 by plating only in the portion inside the recessed groove A3, and This serves as a mask when the plating layers 19 and 20 for soldering are formed only on the surfaces of the connection terminal electrodes 17 and 18 by plating.
[0033]
Next, FIGS. 13 and 14 show a manufacturing method according to another embodiment.
[0034]
In the manufacturing method according to this another embodiment, as shown in FIG. 13, the concave groove A3 is formed by forming a concave groove A3 'for forming one concave 13' in the resistor 12 and the other concave A3. In addition to the groove A3 "for forming the groove 14 ', the dimension between the two grooves A3' and A3" is set to a length L3 for obtaining a predetermined resistance value.
[0035]
Then, as shown in FIG. 14, metal plating layers A4 ', A4 "are formed in the respective recessed grooves A3', A3" by plating, and the metal plating layers A4 ', A4 "are connected to connection terminals. The electrodes are 17 'and 18', and the others are the same as the above-mentioned methods (1) to (7). With this method, a chip resistor 11 'having the structure shown in FIG. 15 is obtained. Can be.
[0036]
In short, in the present invention, "providing recesses at both left and right ends of the back surface of the resistor" means that both recesses 13 and 14 are in contact with both end surfaces 12c and 12d of resistor 12 as shown in FIG. 15, the two concave portions 13 'and 14' forming the connection terminal electrodes 17 'and 18' are in close proximity without contacting both end surfaces 12c 'and 12d' of the resistor 12 '. It includes both the case and the case where it is done.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a chip resistor according to the prior art.
FIG. 2 is a perspective view showing a chip resistor according to the embodiment of the present invention.
FIG. 3 is a sectional view taken along line III-III in FIG. 2;
FIG. 4 is a bottom view of FIG. 2;
FIG. 5 is a sectional view taken along line VV of FIG. 2;
FIG. 6 is a sectional view taken along line VI-VI of FIG. 2;
FIG. 7 is a perspective view showing a first step in the method of manufacturing the chip resistor.
FIG. 8 is a perspective view showing a second step in the manufacturing method.
FIG. 9 is a perspective view showing a third step in the manufacturing method.
FIG. 10 is an enlarged sectional view taken along line XX of FIG. 9;
FIG. 11 is a perspective view showing a fourth step in the manufacturing method.
FIG. 12 is an enlarged sectional view taken along the line XII-XII of FIG. 11;
FIG. 13 is a cross-sectional view showing a first step in another manufacturing method.
FIG. 14 is a sectional view showing a second step in another manufacturing method.
FIG. 15 is a longitudinal sectional front view of a chip resistor according to another manufacturing method.
[Explanation of symbols]
11, 11 'Chip resistors 12, 12' Resistors 12a, 12a 'Resistor front surfaces 12b, 12b' Resistor back surfaces 12c, 12d, 12c ', 12d' Resistor end surfaces 13, 14, 13 ', 14 'Concave portions 15, 16 Insulators 17, 18, 17', 18 'Connection terminal electrode A Material metal plate A1 Surface of material metal plate A2 Back surface B1, B2 of material metal plate Cutting line A3, A3', A3 " A4, A4 ', A4 "metal plating layer

Claims (4)

A concave portion is provided at the left and right ends of the back surface of the resistor formed of a metal plate, and a connection terminal electrode made of a metal having a lower resistance than the resistor is provided in the concave portion. A chip resistor having a low resistance value, wherein a portion between the two connection terminal electrodes on the back surface is covered with an insulator. 2. The chip resistor having a low resistance value according to claim 1, wherein the surfaces of the two connection terminal electrodes are substantially flush with the surface of the insulator, or project from the surface of the insulator. vessel. 3. The chip resistor having a low resistance value according to claim 1, wherein the both connection terminal electrodes are formed of a metal plating layer. A process of manufacturing a material metal plate formed by arranging and integrating a number of resistors constituting one chip resistor,
A step of covering at least the back surface of the material metal plate with an insulator,
Depressed grooves as recesses are formed in the right and left ends of each resistor on the back surface of the metal plate while cutting out portions of the insulator corresponding to the left and right ends of each resistor. The process of setting up,
Forming a metal plating layer as a connection terminal electrode with a metal having a lower resistance than the material metal plate on a portion in each of the concave grooves on the back surface of the material metal plate;
A step of dividing the material metal plate for each of the resistors;
A method for manufacturing a chip resistor having a low resistance value, comprising:

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