JP4338070B2 - Multilayer electronic component and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer electronic component such as a chip coil and a method for manufacturing the same, and relates to a surface mount multilayer type in which a spiral coil conductor is disposed inside a multilayer body mainly formed of a magnetic body or a non-magnetic body. The present invention relates to an electronic component and a manufacturing method thereof.
[0002]
[Prior art]
In a conventional multilayer electronic component of this type, as shown in FIG. 2A, a coil conductor 2 and a magnetic or non-magnetic material are laminated to form a spiral coil inside the laminate 1. As shown in FIG. 2B, it is known that a gap 3A exists between the coil conductor lead-out portion 21 exposed to the peripheral side surface of the laminate and the laminate 1 after the laminate 1 is fired.
[0003]
Further, in the state in which the end electrode 3 is formed at both ends in the stacking direction of the laminate 1 by baking after applying the end electrode to the laminate 1, the corner portion 31 of the laminate 1 or the end portion of the end electrode wrap-around 32, the coating thickness of the end electrode 3 is extremely reduced. Therefore, when the coil conductor lead-out portion 21 is formed near the corner portion 31 or end electrode wrap around end portion 32 of the laminate, FIG. As shown in FIG. 2B, the gap 3B is easily generated in the end electrode 3, and in the subsequent steps such as electroplating of the end electrode, moisture tends to stay in the gaps 3A and 3B. As shown in C), the multilayer electronic component is completed by being shielded only by the electroplating film (metal plating film) 4 while the moisture is retained.
[0004]
When the multilayer electronic component shielded only by electroplating while retaining the moisture is mounted on the circuit board, FIG. 3A (the same parts as those in FIG. 2 are given the same reference numerals). As shown in (2), the solder is usually mounted on a solder 6 printed on a land 5 of a circuit board (printed board) 7 with a metal mask or the like, and then reflowed and fixed with solder. When reflowed at a temperature of 183 ° C. or higher, as shown in FIG. 3 (B), the water staying in the electronic components (in the gaps 3A and 3B) is thermally expanded and vaporized, and the electroplating film 4 is formed. When the molten solder 61 scatters at the same time as it breaks, and the splattered solder 6 </ b> A reaches the terminals of other nearby electronic components and rapidly cools, it becomes a short circuit due to the solder, causing circuit operation to be disabled.
[0005]
In the case of lead-free solder, which has been widely used in recent years, this phenomenon is more prominent because the melting temperature of the solder is higher and the reflow temperature must be set higher. It is coming.
[0006]
As a known example, as mentioned in the present invention, it is not intended to eliminate the void generated in the end electrode of the multilayer electronic component and thus eliminate the solder scattering during the component reflow, but it is structurally similar. Patent Document 1 and Patent Document 2 below can be cited.
[0007]
Further, in the laminate made of a magnetic material or a non-magnetic material, as shown in FIG. 2B, there is a gap 3A between the coil conductor leading portion 21 exposed to the peripheral side surface of the laminate and the laminate 1 after firing. For example, Patent Literature 3 and Patent Literature 4 listed below can be cited.
[0008]
[Patent Document 1]
JP-A-10-284324 [Patent Document 2]
Japanese Patent Laid-Open No. 11-265822 [Patent Document 3]
Japanese Patent No. 2983049 [Patent Document 4]
Japanese Patent No. 2987176 [0009]
FIG. 4 is a cross-sectional view of the multilayer electronic component disclosed in Patent Document 2, wherein 1 is a multilayer body, 2 is a coil conductor, 21 is a coil conductor lead-out portion, and 3 is an end electrode. In this case, the coil conductor lead-out portion is connected to the end portion of the end electrode that wraps around the side surface of the laminate. Therefore, it does not solve the problem of solder scattering during reflow caused by voids.
[0010]
[Problems to be solved by the invention]
In view of their problems, to prevent the gap occurrence of end electrodes, thus, by the score without retention of moisture into the end electrodes in the subsequent electroplating such process, in a subsequent reflow process An object of the present invention is to provide a multilayer electronic component capable of preventing a short circuit accident with other electronic components in the vicinity due to the scattering of solder and a method for manufacturing the same.
[0011]
Other objects and novel features of the present invention will be clarified in embodiments described later.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a multilayer electronic component according to the invention of claim 1 of the present application,
In a laminated electronic component having a substantially rectangular parallelepiped shape in which a coil conductor is laminated with a magnetic body or a nonmagnetic body to form a coil inside the laminated body,
End electrodes are provided at both ends of the laminate, and an electroplating film is formed on the end electrodes,
The coil conductor is exposed on a peripheral side surface of the laminate,
Exposed position of the lead portion of the coil conductor, Ri Oh the maximum area portion of the electrode thickness at a portion where the end electrode goes around the peripheral side surface of the laminate, the maximum area portion, said end electrodes the laminate In the middle of the part that wraps around
The gap generated between the lead portion of the coil conductor and the laminate is characterized that you have been closed by the end electrode.
[0013]
As described above, when the coil conductor is exposed on the peripheral side surface of the laminate, the end electrode that is electrically connected to the coil conductor has a corner portion or end electrode wrap around end portion where the coating thickness is extremely reduced. By disposing the coil conductor lead-out portion in the maximum electrode thickness region portion, the gap generated in the coil conductor lead-out portion can be completely shielded (closed) by the end electrodes.
[0016]
The manufacturing method of the multilayer electronic component according to the invention of claim 2 of the present application is as follows:
A coil conductor and a magnetic or non-magnetic material are laminated to form a coil inside the laminate, end electrodes are provided at both ends of the laminate, and an electroplating film is formed on the end electrodes. In the method for manufacturing a multilayer electronic component having a rectangular parallelepiped shape,
The maximum electrode thickness region in the portion where the end electrode wraps around the peripheral side surface of the multilayer body is present at the substantially center of the portion where the end electrode wraps around the peripheral side surface of the multilayer body, and the coil conductor is drawn out. as exposed position to the laminate peripheral side surface portion is pre-Symbol maximum area portion, by adjusting the exposure position to the laminate peripheral side surface of the lead portion of the coil conductor and wraparound dimensions of said end electrodes The gap generated between the lead portion of the coil conductor and the laminated body is closed by the end electrode .
[0017]
Thus, the application condition setting of the end electrode to be applied and the adjustment of the exposure position of the coil conductor lead-out portion to the laminated body peripheral side surface with respect to the exposure position of the coil conductor lead-out portion to the laminate peripheral side surface, By making the end electrode thickness the maximum region, a multilayer electronic component that can be easily mass-produced can be obtained.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a multilayer electronic component and a manufacturing method thereof according to the present invention will be described below with reference to the drawings.
[0022]
FIG. 1 is a cross-sectional view of a substantially rectangular parallelepiped chip-type inductor as an embodiment of a multilayer electronic component according to the present invention. Magnetic bodies and spiral coil conductors 2 are alternately laminated by a printing lamination method. The winding start portion and the end portion of the coil conductor 2 are coil conductor lead-out portions 21 and are exposed on the peripheral side surface of the multilayer body 1. Here, the printing lamination method is used, but there is no problem even with the sheet lamination method in which a green sheet is printed and provided with a through hole for spirally winding the coil conductor 2 and laminated. .
[0023]
Further, the chip-type inductor as the multilayer electronic component is obtained by printing and laminating a large number of coil conductor patterns, cutting it into a single chip (that is, a rectangular parallelepiped multilayer body 1), firing at a high temperature, An electrode paste to be the terminal electrode 3 is applied and baked on both ends of the laminate 1 in the stacking direction, and an electroplating film 4 is formed on the end electrode 3 by electroplating to complete the electronic component. Is a region 30 where the electrode thickness is maximum at a portion that wraps around the circumferential side surface of the laminated body at the position of the coil conductor lead-out portion 21 exposed on the circumferential side surface of the laminated body 1.
[0024]
Thus, the exposure position of the coil conductor lead-out portion 21 to the peripheral surface of the multilayer body is the maximum region portion 30 of the electrode thickness in the portion of the end electrode 3 that wraps around the peripheral surface of the multilayer body. This is achieved by adjusting the wraparound dimension of the partial electrode 3 (electrode paste application dimension on the circumferential surface of the laminate) and the viscosity of the electrode paste, and adjusting the exposure position of the coil conductor lead-out portion 21 on the circumferential surface of the laminate. it can.
[0025]
Since the maximum electrode thickness region 30 in the portion where the end electrode 3 wraps around the peripheral side surface of the laminate 1 is slightly gentle, the coil conductor lead-out portion 21 has a maximum position (maximum point) of the electrode thickness. If the positional deviation is less than about 4 times the thickness of the exposed electrode, the gap generated in the coil conductor lead-out portion 21 can be completely shielded (closed without spreading the gap). In addition, when the product dimensions are 1608 type (vertical 1.6 mm, horizontal 0.8 mm, thickness 0.8 mm), the exposed electrode thickness of the coil conductor lead-out portion 21 is about 20 μm, 2012 type (vertical 2.0 mm, horizontal 1.2 mm). In the case of 1005 type (length 1.0 mm, width 0.5 mm, thickness 0.5 mm), the thickness is about 14 μm.
[0026]
The electroplating is completed by sequentially performing plating of copper and nickel and tin, nickel and tin, nickel and gold, nickel and palladium and gold, nickel and palladium and silver, or nickel and silver, etc. Nickel is the lower layer, and tin, gold and silver are the upper layer plating).
[0027]
According to this embodiment, the following effects can be obtained.
[0028]
(1) A coil conductor lead-out portion 21 exposed on the peripheral surface of the laminated body after firing the laminated body 1 in which the coil conductor 2 and a magnetic material or a nonmagnetic material are laminated to form a spiral coil inside the laminated body 1; A gap is generated between the laminates 1, but the region where the exposed position of the coil conductor lead-out portion 21 wraps around the peripheral surface of the laminate of the end electrode 3 so that the gap does not reach the end electrode. by setting so that 30, in a subsequent electroplating such process, it is the score without retention of moisture into the end electrode. As a result, in the multilayer electronic component shown in the present embodiment, it is possible to prevent inconvenience that a short circuit with other electronic components in the vicinity due to scattering of solder occurs in the reflow process, and a highly reliable product is manufactured. It becomes possible.
[0029]
(2) The position where the coil conductor lead-out portion 21 is exposed on the peripheral surface of the laminate is the end region electrode 30 having the maximum electrode thickness at the portion that wraps around the peripheral surface of the laminate. 3 is easily realized by adjusting the wraparound dimension (electrode paste application dimension on the circumferential surface of the laminate) and the viscosity of the electrode paste, and adjusting the exposed position of the coil conductor lead-out portion 21 on the circumferential surface of the laminate. it can.
[0030]
(3) Since the maximum electrode thickness region 30 in the portion where the end electrode 3 wraps around the peripheral side surface of the multilayer body 1 is slightly gentle, the coil conductor lead-out portion 21 with respect to the maximum position (maximum point) of the electrode thickness. If the positional deviation is less than about 4 times the exposed electrode thickness, the gap generated in the coil conductor lead-out portion 21 can be completely shielded and the generation of the gap in the end electrode 3 itself can be prevented.
[0031]
【Example】
As an example of the present invention, the laminate 1 is made of a paste mainly composed of Ni—Cu—Zn ferrite as a magnetic material, the interlayer thickness is about 50 μm, and the coil conductor 2 is made of a paste mainly composed of silver. Use a substantially semicircular pattern with a pattern width of about 150 μm, a pattern electrode thickness of about 20 μm, and a pattern inner diameter of about 350 μm. The coil conductor pattern and the magnetic paste are alternately printed and laminated to obtain a large number of pieces. The substrate was completed. Then, it cut | disconnects so that it may become a chip | tip single-piece | unit with a dicer, etc., and after barrel-polishing for the purpose of removing the edge part of a chip | tip, it baked at about 880 degreeC in baking atmosphere in the air, and the laminated body 1 is completed did. Further, the end electrode 3 is applied with an electrode paste mainly composed of silver and baked at about 700 ° C., and electroplating is performed in the order of copper, nickel, and tin to form a substantially rectangular chip-shaped inductor. Completed. The completed dimensions at that time were 1.6 mm in length, 0.8 mm in width and thickness. The exposed position of the coil conductor lead-out portion 21 on the peripheral surface of the laminate was adjusted to be the maximum region portion 30 of the electrode thickness at the portion of the end electrode 3 that wraps around the peripheral surface of the laminate.
[0032]
In order to confirm the effect of the present invention, the chip type inductor of the above example was subjected to a reflow experiment with a profile having a peak temperature of 250 ° C., and solder scattering at the terminal electrode portion was confirmed. Solder scattering was observed in 21 of the pieces, but even 40,000 pieces were 0 in the product of the present invention (Example). Also from this result, it can be judged that the method for forming an end electrode of the multilayer electronic component of the present invention is surely effective.
[0033]
Although the embodiments and examples of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited thereto and various modifications and changes can be made within the scope of the claims. I will.
[0034]
【The invention's effect】
As described above, according to the present invention, in a laminated electronic component having a substantially rectangular parallelepiped shape in which a coil conductor and a magnetic body or a nonmagnetic body are laminated to form a coil inside the laminated body, Even if there is a gap between the coil conductor lead-out portion exposed to the laminate and the laminate, the exposed region of the coil conductor lead-out portion is the maximum region of the electrode thickness in the portion that wraps around the peripheral surface of the laminate. made by that, the without voids spread to the end electrodes, in subsequent electroplating such process, it is the score without retention of moisture into the end electrode. As a result, in the multilayer electronic component of the present invention, it is possible to prevent inconvenience that a short circuit with other electronic components in the vicinity due to scattering of solder occurs in the reflow process, and it is possible to manufacture a highly reliable product. Become.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a multilayer electronic component and a manufacturing method thereof according to the present invention.
2A is a cross-sectional view after baking an end electrode, and FIG. 2B is a gap between the coil conductor lead-out portion and the laminated body, and an end portion in FIG. The expanded sectional view which shows the space | gap of an electrode, (C) is an expanded sectional view which shows the state which electroplated to (B).
3A is an enlarged cross-sectional view showing a state in which an end electrode is electroplated in a conventional multilayer electronic component, and FIG. 3A is a mounted state for mounting on a printed circuit board; FIG. (A) is an expanded sectional view which shows the scattering state of the solder which generate | occur | produces at the time of reflow.
FIG. 4 is a cross-sectional view of a multilayer electronic component disclosed in Japanese Patent Laid-Open No. 11-265822.
DESCRIPTION OF SYMBOLS 1 Laminated body 2 Coil conductor 3 End electrode 3A The space | gap 3B between coil conductor lead-out parts and a laminated body 3B End electrode gap 4 Electroplating film 5 Land 6 Printed solder 6A Spattered solder 7 Circuit board 21 Coil conductor lead-out part 30 Electrode thickness maximum region portion 31 End electrode laminated body corner portion 32 End electrode wraparound end portion 61 Molten solder

Claims (2)

In a laminated electronic component having a substantially rectangular parallelepiped shape in which a coil conductor is laminated with a magnetic body or a nonmagnetic body to form a coil inside the laminated body,
End electrodes are provided at both ends of the laminate, and an electroplating film is formed on the end electrodes,
The coil conductor is exposed on a peripheral side surface of the laminate,
Exposed position of the lead portion of the coil conductor, Ri Oh the maximum area portion of the electrode thickness at a portion where the end electrode goes around the peripheral side surface of the laminate, the maximum area portion, said end electrodes the laminate In the middle of the part that wraps around
Multilayer electronic component gap that occurs between the lead portion and the laminate of the coil conductor is characterized that you have been closed by the end electrode. A coil conductor and a magnetic or non-magnetic material are laminated to form a coil inside the laminate, end electrodes are provided at both ends of the laminate, and an electroplating film is formed on the end electrodes. In the method for manufacturing a multilayer electronic component having a rectangular parallelepiped shape,
The maximum electrode thickness region in the portion where the end electrode wraps around the peripheral side surface of the multilayer body is present at the substantially center of the portion where the end electrode wraps around the peripheral side surface of the multilayer body, and the coil conductor is drawn out. as exposed position to the laminate peripheral side surface portion is pre-Symbol maximum area portion, by adjusting the exposure position to the laminate peripheral side surface of the lead portion of the coil conductor and wraparound dimensions of said end electrodes A method of manufacturing a multilayer electronic component, wherein a gap generated between the lead portion of the coil conductor and the multilayer body is closed by the end electrode .

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