JP4978307B2 - Electronic component with lead wire, and method for manufacturing electronic component with lead wire - Google Patents

Description

  The present invention relates to an electronic component with a lead wire, and a method of manufacturing the electronic component with a lead wire, and more specifically, an electronic component with a lead wire in which lead wires are connected to both end faces of various electronic components such as a multilayer ceramic capacitor, and the like. It relates to a manufacturing method.

  Today, electronic components with lead wires in which lead wires are connected to electronic components such as multilayer ceramic capacitors are widely used in various electronic devices.

  The electronic component with lead wire is configured by providing a pair of terminal electrodes at both ends of a component body formed in a substantially rectangular parallelepiped shape, and soldering the lead wire to each end face of the terminal electrode. Thus, the terminal electrode and the lead wire are electrically connected.

  By the way, in this type of electronic component with a lead wire, the lead wire is generally connected to a terminal electrode by a so-called flow soldering method.

  FIG. 8 is a diagram schematically showing an outline of the flow soldering method.

  The electronic component 103 is sandwiched between a pair of lead wires 102a and 102b held by the carrier tape 101, and the electronic component 103 is immersed in the solder liquid 104 so that the electronic component 103 is positioned downward, and is heated and solidified to lead. The wires 102a and 102b are connected to the terminal electrodes 105a and 105b.

  However, in the above-described flow soldering method, since the electronic component 103 is immersed in the solder solution 104, solder pools are formed at the corners 106a and 106b between the lead wires 102a and 102b and the electronic component 103, and the corners are formed. A large amount of the solder liquid 104 adheres to the portions 106a and 106b. When the solder liquid 104 is heated and solidified, the solder condenses, so that contraction stress is generated. The shrinkage stress acts as a force for peeling the terminal electrodes 105a and 105b from the component main body 107. As a result, the component main body 107 may be cracked or the interface between the terminal electrodes 105a and 105b and the component main body 107 may be peeled off. is there.

  Therefore, as shown in FIG. 9, a radial lead type multilayer ceramic electronic component having a devised lead wire shape has been proposed (Patent Document 1).

  In Patent Document 1, the lead wires 110a and 110b have support shaft portions 108a and 108b that do not contact the terminal electrodes 105a and 105b, and soldering shaft portions 109a and 109b that are in close contact with the terminal electrodes 105a and 105b. The support shaft portions 108a and 108b are formed to be bent outward from the soldering shaft portions 109a and 109b in a direction away from the terminal electrodes 105a and 105b. Furthermore, the lead wires 110a and 110b have the soldering shaft portions 109a and 109b surfaced on a flat surface, and steps 111a and 111b are provided as lower edges of the flat surface at the boundary with the support shaft portions 108a and 108b. It has been. And the whole surface of terminal electrode 105a, 105b is coat | covered with solder 112a, 112b by the flow soldering system.

  In this way, by bending the support shaft portions 108a and 108b of the lead wires 110a and 110b outward from the soldering shaft portions 109a and 109b, corner portions 113a formed between the lead wires 110a and 110b and the electronic component 103 are formed. , 113b can prevent more solder from attaching than necessary. As a result, even if the solder is solidified by heating, the shrinkage stress can be kept small, and as a result, cracks in the component body 107 and the interface between the terminal electrodes 105a and 105b and the component body 107 are prevented from peeling. It becomes possible to do.

JP 2003-68563 A

  However, although the above-mentioned patent document 1 devises the shape of the lead wire, since the flow soldering method is adopted, the entire surface of the electronic component 103 is in contact with the solder liquid as in FIG. Since the solder adheres only to the metal part and does not adhere to the non-metal part such as ceramic, the solder liquid adheres so as to cover the entire terminal electrodes 105a and 105b. When the solder solution is heated and solidified, solder contraction inevitably occurs. Therefore, when the lead wire is pulled in the axial direction indicated by the arrow x, stress is applied to the coated end portion of the solder (indicated by the arrow y). . For this reason, peeling of the interface between the terminal electrodes 105a and 105b and the component main body 107 and generation of cracks in the component main body 107 cannot be completely prevented.

  In this way, when the flow soldering method is adopted, in any case, the solder 112a and 112b covers the entire terminal electrodes 105a and 105b. There is a possibility of causing destruction of the element such as generation or interface peeling between the terminal electrodes 105a and 105b and the component main body 107.

  Further, in Patent Document 1, the shape is devised by providing steps 111a and 111b on the lead wires 110a and 110b. However, for a large variety of electronic parts, the lower edge of the flat surface of the terminal electrodes 105a and 105b and the leads Arranging the lead wires 110a and 110b and the electronic component 103 so that the steps 111a and 111b of the wires 110a and 110b are always aligned requires high technology in terms of production technology, and dimensional errors between the components. Considering the above, it is difficult to design. And when these are not arranged in a desired position, the amount of solder adhering to the corners 113a and 113b increases on the contrary, and there is a possibility that the product yield is lowered.

  The present invention has been made in view of the above circumstances, and reduces the absolute amount of solder required for soldering, and has excellent mechanical strength with an electronic component with a lead wire, and a method for manufacturing the electronic component with a lead wire The purpose is to provide.

In order to achieve the above object, an electronic component with a lead wire according to the present invention has a pair of terminal electrodes coated on both end portions of a component body formed in a substantially rectangular parallelepiped shape, and the lead wire is each of the terminal electrodes. In the electronic component with a lead wire connected to the end surface of the component body, the terminal electrode is formed so as to cover the end surface of the component main body, a part of the ridge line portion of the component main body, and the four side surfaces of the component main body, An electrode covered end is formed in the vicinity of the end surface of the component main body and on a line substantially parallel to the end surface, and the solder has a solder covered end on the end face side of the terminal electrode rather than the electrode covered end. , the for said part of the terminal electrode is connected to the terminal electrode is the lead wire is covered with solder, the terminal electrodes of the solder by a reflow heat treatment, including the entire surface of the end face of the terminal electrode It is characterized in that the rate is 30 to 80% by area ratio.

  Moreover, the electronic component with a lead wire of the present invention is characterized in that the solder is cream solder.

The method for manufacturing an electronic component with a lead wire according to the present invention provides a pair of terminal electrodes on both ends of a component body formed in a substantially rectangular parallelepiped shape to provide an electronic component, and each end surface of the terminal electrode. In a method of manufacturing an electronic component with a lead wire in which a lead wire is soldered to the terminal electrode and the lead wire, the end surface of the component main body, a part of the ridge line portion of the component main body, and the component main body The terminal electrode is formed so as to cover the four side surfaces and have an electrode covering end portion in the vicinity of the end surface of the component main body and on a straight line substantially parallel to the end surface, and a solder paste is used as the solder, and the pair of leads After the cream solder is attached to the tip region of the wire, the electronic component is sandwiched between the pair of lead wires so that the terminal electrode is in contact with the cream solder, and then reflow heating is performed. Performs management, a portion of the terminal electrode including the entire surface of the end face of the terminal electrodes as solder covering end part is formed on the end surface of the terminal electrode than the electrode covering end portions coated with the solder The solder coverage with respect to the terminal electrode is 30 to 80% in area ratio.

According to the electronic component with a lead wire, the terminal electrode is formed so as to cover an end surface of the component main body, a part of a ridge line portion of the component main body, and four side surfaces of the component main body, and the component main body. Reflow heating so that an electrode covering end is formed in a vicinity of the end face of the electrode and on a straight line substantially parallel to the end face, and the solder has a solder covering end on the end face side of the terminal electrode rather than the electrode covering end. processing the portion of the terminal electrode including the entire surface of the end surface of the terminal electrodes is the lead wire is coated with the solder is connected to the terminal electrodes by, 30 coverage for the terminal electrode of the solder by area Since it is 80%, the solder does not cover the entire surface of the terminal electrode, and the absolute amount of solder to be coated is reduced. Then, the Kutsugaetan unit solder is always an intermediate position of the terminal electrodes a facet substantially parallel straight lines on the terminal electrode. Therefore, although the shrinkage stress in the solder by heating solidification of the solder occurs, even lead is pulled in the axial direction, the stress is loaded on the Kutsugaetan part solder, loaded to the electrode covering end portions of the terminal electrodes Can be avoided. As a result, it is possible to prevent the interface between the terminal electrode and the component main body from being peeled off or cracks from being generated in the component main body, thereby improving the mechanical strength.

According to the method for manufacturing an electronic component with a lead wire, the end surface of the component main body, a part of the ridge line portion of the component main body, and the four side surfaces of the component main body are covered and in the vicinity of the end surface of the component main body. Forming the terminal electrode so as to have an electrode covering end on a straight line substantially parallel to the end face , using cream solder for the solder, and attaching the cream solder to the tip region of the pair of lead wires, The electronic component is sandwiched between the pair of lead wires so that the terminal electrode is in contact with the cream solder, and then reflow heat treatment is performed, and the end surface side of the terminal electrode is coated with solder more than the electrode coating end portion. a portion of the terminal electrode including the entire surface of the end face of the terminal electrode so that the end portion is formed by coating with the solder, the solder coverage with respect to the terminal electrodes 30 to 80% by area ratio In, it is possible to easily improve the mechanical strength without adding processing to the shape of the lead wire.

  That is, it is possible to easily manufacture an electronic component with a lead wire having low cost, high efficiency, and excellent reliability without requiring complicated lead wire processing as in Patent Document 1.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a partially broken front view showing an embodiment of a ceramic capacitor as an electronic component provided for the present invention.

  This multilayer ceramic capacitor 1 includes a component body 2 mainly composed of a ceramic material formed in a substantially rectangular parallelepiped shape, and a conductive material such as Ag or Cu formed at both ends of the component body 2 by baking or the like. Terminal electrodes 3a and 3b.

The terminal electrodes 3a and 3b are formed so as to cover the end surface 2a of the component main body 2, a part of the ridge line portion 2b, and the four side surfaces of the component main body 2, and are in the vicinity of the end surface 2a and substantially parallel to the end surface 2a. Electrode- coated end portions 10a and 10b are formed on the top.

  The component body 2 includes a large number of internal electrodes 4a and 4b so that the internal electrode 4a electrically connected to the terminal electrode 3a and the internal electrode 4b electrically connected to the terminal electrode 3b are staggered. It is buried.

  FIG. 2 is a front view showing an embodiment of an electronic component with lead wires according to the present invention.

In the electronic component with lead wires, the terminal electrodes 3a, 3b of the multilayer ceramic capacitor 1 and the lead wires 5a, 5b are electrically connected via solders 6a, 6b, and the entire surface of the terminal electrodes 3a, 3b. Are not covered with the solder 6a, 6b, the solder 6a, 6b is on the end face side of the electrode covering end portions 10a, 10b of the terminal electrodes 3a, 3b, that is, substantially parallel to the end face of the component body 2a. Solder-coated end portions 11a and 11b are formed at intermediate positions of the terminal electrodes 3a and 3b (hereinafter simply referred to as “intermediate positions”).

  Specifically, the solders 6a and 6b are made of cream solder, and the area of coverage of the solders 6a and 6b on the entire surface of the terminal electrodes 3a and 3b (hereinafter referred to as “solder coverage”) by reflow heat treatment. Solder-coated end portions 11a and 11b are formed at intermediate positions of the terminal electrodes 3a and 3b so that the ratio is 30 to 80%.

  The reason why the solder coverage is 30 to 80% in this way is as follows.

  In the reflow heat treatment using cream solder, the solder 6a and 6b are applied to the desired regions of the terminal electrodes 3a and 3b including the connection portions between the lead wires 5a and 5b and the terminal electrodes 3a and 3b, and then the heat treatment is performed. Become. Therefore, the solder coverage can be controlled by the amount of solder 6a and 6b applied and the processing conditions of the reflow heat treatment.

  Therefore, it is possible to prevent the solder 6a and 6b from covering the entire surface of the terminal electrodes 3a and 3b, thereby avoiding the occurrence of interface peeling and cracking, and improving the mechanical strength. It becomes possible.

  FIG. 3 is an enlarged view of a portion A in FIG. 2 and shows an action state of stress applied to the solder 6b when the lead wire 5b is pulled in the axial direction.

  Even when reflow heat treatment is performed, the solder 6b shrinks when solidified after heating. When the lead wire 5b is pulled in the axial direction indicated by the arrow X, the stress is concentrated on the solder-coated end portion 11b indicated by the arrow Y. That is, unlike the flow soldering method, the solder does not cover the entire terminal electrode, and the solder covered end portion 11b is in the middle position between the terminal electrodes 3a and 3b, so that the lead wire 5b is in the axial direction indicated by the arrow X. Even if it is pulled, the stress is applied to the solder-coated end portion 11b indicated by the arrow Y, and as a result, the interface between the terminal electrode 3b and the component main body 2 is prevented from being peeled off, and the component main body 2 is prevented from cracking. And mechanical strength can be improved.

  And in order to acquire such an expected effect, it is necessary to make a solder coverage into 80% or less by area ratio. This is because when the solder coverage exceeds 80% in terms of area ratio, the solder coated end portions 11a and 11b are too close to the coated end portions 10a and 10b of the terminal electrodes 3a and 3b, so that the above-described interface peeling and cracking occur. This is because the mechanical strength may not be improved.

  On the other hand, when the solder coverage is less than 30%, the solder coverage is too small. Therefore, when the lead wires 5a and 5b are pulled in the axial direction, the lead wires 5a and 5b are easily peeled from the terminal electrodes 3a and 3b. There is a risk that.

  Therefore, in the present embodiment, the solder coverage is set to 30 to 80% by area ratio.

In this way, by setting the solder coverage to an area ratio of 30 to 80 %, the mechanical strength can be improved without performing the shape processing of the lead wires 5a and 5b, which is difficult both in terms of design and production technology. Can be achieved.

  FIG. 4 is a manufacturing process diagram showing the first embodiment of the method for manufacturing the electronic component with lead wires.

That is, as shown in FIG. 4A, the cream solders 7a and 7b are applied to the tips of the lead wires 5a and 5b, and the cream solders 7a and 7b are attached to the lead wires 5a and 5b. Next, as shown in FIG. 4B, the multilayer ceramic capacitor 1 is sandwiched between the lead wires 5a and 5b to which the cream solders 7a and 7b are attached. Then, reflow heat treatment is performed to melt the cream solders 7a and 7b. Then, as shown in FIG. 4 (c), the heat-solidified solder 6a, 6b forms solder-coated end portions 11a, 11b on the end face side of the terminal electrodes 3a, 3b rather than the electrode-coated end portions 10a, 10b, A part of the terminal electrodes 3a and 3b is covered so that the solder coverage is 30 to 80%, whereby an electronic component with a lead wire is manufactured.

  As described above, the solder coverage can be easily controlled by the application amount of the cream solders 7a and 7b and the processing conditions of the reflow heat treatment.

As described above, in this embodiment, after the cream solders 7a and 7b are applied and attached to the tips of the lead wires 5a and 5b , a pair of leads are arranged so that the terminal electrodes 3a and 3b are in contact with the cream solders 7a and 7b. The multilayer ceramic capacitor 1 is sandwiched between the wires 5a and 5b, and then reflow heat treatment is performed. Since part of the terminal electrode is covered with the solder so that the portions 11a and 11b are formed, and the solder coverage with respect to the terminal electrode is 30 to 80% in area ratio, the absolute amount of solder to be covered is also Reduced. And, without subjecting the lead wires 5a and 5b to complicated shape processing, it is possible to easily improve the mechanical strength, thereby making it possible to produce an electronic component with lead wires that is low-cost, highly efficient and highly reliable. Can be manufactured.

  FIG. 5 is a manufacturing process diagram showing a second embodiment of a method for manufacturing an electronic component with lead wires.

In the second embodiment, first, a molten solder obtained by melting solid solder is prepared. Then, the lead wires 5a and 5b are slanted and the lead wires 5a and 5b are immersed in the molten solder, and the preliminary solders 8a and 8b are attached to the lead wires 5a and 5b as shown in FIG. . After that, as in the first embodiment, as shown in FIG. 5B, the multilayer ceramic capacitor 1 is sandwiched between the lead wires 5a and 5b to which the preliminary solders 8a and 8b are attached, and then reflow heating is performed. Processing is performed to melt the preliminary solders 8a and 8b. Then, as shown in FIG. 5C, the heat-solidified solder 6a, 6b forms solder-coated end portions 11a, 11b on the end face side of the terminal electrodes 3a, 3b rather than the electrode-coated end portions 10a, 10b, A part of the terminal electrodes 3a and 3b is covered so that the solder coverage is 30 to 80%, whereby an electronic component with a lead wire is manufactured.

  Even when the lead wires 5a and 5b are immersed in the molten solder in which the solid solder is melted in this manner and the preliminary solders 8a and 8b are attached to the lead wires 5a and 5b, the amount of the preliminary solder applied and reflow heating are used. The solder coverage can be easily controlled by the processing conditions of the processing, and the same effects as those of the first embodiment can be obtained.

  The present invention is not limited to the above embodiment. In the above embodiment, the multilayer ceramic capacitor is exemplified as the electronic component. However, it is needless to say that the electronic component can be similarly applied as long as it is an electronic component in which a lead wire is connected to the end face of the terminal electrode. The present invention can also be applied to other chip type electronic components.

  Next, examples of the present invention will be specifically described.

  As an electronic component, 10 multilayer ceramic capacitors having a length L of 3.2 mm, a width of 1.6 mm, a thickness of 1.6 mm, and a distance e from the end face of the terminal electrode of 0.3 to 0.8 mm are prepared (see FIG. 6) and 20 lead wires were prepared.

  Next, cream solder was applied to the tip of each lead wire, and the cream solder was extended to the width of the multilayer ceramic capacitor while being dried with an air heater.

  And the said multilayer ceramic capacitor was inserted between a pair of lead wires, the reflow heat processing was performed, and the cream solder was fuse | melted. And the Example sample of the sample numbers 1-10 controlled so that a solder coverage might be 30 to 80% by area ratio was produced. In addition, the solder coating | coated edge part was adjusted so that the distance from an end surface might be 0.2-0.6 mm.

  On the other hand, a multilayer ceramic capacitor having the same shape as the multilayer ceramic capacitor was used (number of samples: 10), and flow soldering was performed to prepare comparative sample samples of sample numbers 1 to 10. That is, a multilayer ceramic capacitor was sandwiched between a pair of lead wires held by a carrier tape, immersed in a solder bath, and heated and solidified to produce comparative sample samples Nos. 1 to 10.

  Next, the tensile test was performed about each sample of the Example and the comparative example, and the tensile strength was measured. That is, one lead wire of each sample was fixed, the other lead wire was pulled at a constant speed of 25 mm / s, and the strength when the lead wire was peeled off from the terminal electrode was measured.

  Table 1 shows the measurement results.

  As is clear from Table 1, the comparative sample was found to have a tensile strength of 5.6 N to 7.9 N and a low average value of 6.7 N.

  On the other hand, the tensile strength of the example sample is 9.9N to 11.3N, the average value is 10.6N, which is much higher than that of the comparative example sample, and the mechanical strength is greatly improved. .

  In addition, the standard deviation is 0.84 for the comparative sample, and 0.54 for the practical sample. Therefore, the practical sample has less variation than the comparative sample, and has high quality and high reliability. It was found that an electronic component with a lead wire having a high efficiency can be obtained.

  The same multilayer ceramic capacitor as in Example 1 was used as an electronic component, and samples Nos. 11 to 20 having different solder coverages were produced. Specifically, a sample with a solder coverage of 10% or less, more than 10% and less than 30%, 30% or more and 80% or less, and more than 80% and less than 100% is prepared by performing reflow heat treatment. And a sample with a solder coverage of 100% was prepared.

  Next, the tensile strength of each of the samples Nos. 11 to 20 was measured in the same manner as in [Example 1].

  Table 2 shows the measurement results.

  As apparent from Table 2, when the solder coverage is reduced to less than 30%, the average tensile strength is as low as 7.2 to 8.6 N, and the mechanical strength is reduced. Also, the standard deviation is as large as 1.09 to 1.29, and the variation is large.

  On the other hand, even when the solder coverage is higher than 80%, the tensile strength is as low as 6.7 to 9.8 N on average, and the mechanical strength is reduced. Also, the standard deviation is as large as 0.84, and the variation is large.

  On the other hand, when the solder coverage is 30 to 80%, the tensile strength is 9.9N to 11.3N, the average value is as high as 10.6N, the standard deviation is as small as 0.54, and variations occur. It was found that can be suppressed.

  FIG. 7 is a diagram showing the relationship between the solder coverage (%) and the tensile strength (N). In the figure, the horizontal axis represents the solder coverage (%), the vertical axis represents the tensile strength (N), and the ♦ marks plot the average values in Table 2. In addition, the solder coverage is “A” of 10% or less, “B” is more than 10% and less than 30%, “C” is 30% or more and 80% or less, “D” is more than 80% and less than 100%, “E” Is 100%.

  As is clear from FIG. 7, the relationship between the solder coverage and the tensile strength has a mountain-shaped curve, and when the solder coverage is 30 to 80% in area ratio, the tensile strength is large and good. It turns out that the electronic component with a lead wire which has mechanical strength is obtained.

It is a partially broken front view of the ceramic capacitor as an electronic component used for this invention. It is a front view which shows one Embodiment of the electronic component with a lead wire which concerns on this invention. It is the A section enlarged view of FIG. It is a manufacturing-process figure which shows 1st Embodiment of the manufacturing method of the electronic component with a lead wire which concerns on this invention. It is a manufacturing-process figure which shows 2nd Embodiment of the manufacturing method of the electronic component with a lead wire which concerns on this invention. It is a figure for demonstrating the dimension shape of the multilayer ceramic capacitor used for the Example of this invention. It is a figure which shows the relationship between solder coverage and tensile strength. It is a figure for demonstrating a flow soldering system. 1 is a front view of a radial lead type multilayer ceramic electronic component described in Patent Document 1. FIG.

Explanation of symbols

1 Multilayer ceramic capacitor (electronic parts)
2 Component body 3a, 3b Terminal electrode 5a, 5b Lead wire 6a, 6b Solder 7a, 7b Cream solder

Claims (3)

In the electronic component with lead wires in which a pair of terminal electrodes are formed on both ends of the component body formed in a substantially rectangular parallelepiped shape, and lead wires are connected to the respective end faces of the terminal electrodes,
The terminal electrode is formed so as to cover an end surface of the component main body, a part of a ridge line portion of the component main body, and four side surfaces of the component main body, and is near the end surface of the component main body and substantially the same as the end surface. An electrode covering end is formed on a parallel straight line,
A part of the terminal electrode including the entire surface of the end surface of the terminal electrode is covered with solder by reflow heat treatment so that the solder has a solder coated end portion on the end face side of the terminal electrode with respect to the electrode covering end portion. The lead wire is connected to the terminal electrode ,
An electronic component with a lead wire, wherein a coverage ratio of the solder to the terminal electrode is 30 to 80% in area ratio.   2. The electronic component with lead wire according to claim 1, wherein the solder is cream solder. A pair of terminal electrodes are formed on both ends of a component body formed in a substantially rectangular parallelepiped shape to provide an electronic component, and a lead wire is soldered to each end face of the terminal electrode, and the terminal electrode, the lead wire, In the method of manufacturing an electronic component with a lead wire connected,
Covering the end surface of the component main body, a part of the ridge line portion of the component main body, and the four side surfaces of the component main body, and having an electrode covering end portion in the vicinity of the end surface of the component main body and on a straight line substantially parallel to the end surface The terminal electrode is formed,
After the cream solder is used for the solder and the cream solder is attached to the tip region of the pair of lead wires, the electronic component is placed between the pair of lead wires so that the terminal electrode contacts the cream solder. One of the terminal electrodes including the entire surface of the end surface of the terminal electrode so that the solder-coated end portion is formed on the end surface side of the terminal electrode with respect to the electrode-coated end portion. A method of manufacturing an electronic component with a lead wire, wherein a portion is covered with the solder, and a solder coverage with respect to the terminal electrode is 30 to 80% in area ratio.

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