JP4997848B2 - Electronic components - Google Patents

Description

  The present invention relates to an electronic component.

As an electronic component, there is known an electronic component that includes a base, a terminal electrode formed on the base, an insulating layer formed on the base, and a protruding electrode formed on the terminal electrode and made of solder. (For example, refer to Patent Document 1).
JP-A-9-134777

  However, in the electronic component described in Patent Document 1, the bonding strength at the interface between the terminal electrode and the protruding electrode is weak, and the terminal electrode and the protruding electrode may peel off due to impact or the like.

  An object of the present invention is to provide an electronic component capable of improving the bonding strength between a terminal electrode and a protruding electrode.

  The inventors of the present invention have made extensive studies on an electronic component that can improve the bonding strength between the terminal electrode and the protruding electrode. As a result of the study, the present inventors formed an insulating layer also on the terminal electrode and formed a plurality of through holes reaching the terminal electrode at the edge of the insulating layer located on the terminal electrode, A new fact is found that the bonding strength between the terminal electrode and the protruding electrode is improved by sandwiching the edge of the insulating layer with the terminal electrode and connecting the protruding electrode and the terminal electrode through a plurality of through holes. It came to.

  Based on this fact, the electronic component according to the present invention includes a base, a terminal electrode formed on the base, and an insulating layer formed on the base and the terminal electrode so that at least a part of the terminal electrode is exposed. A protruding electrode made of solder and formed on the terminal electrode, and the insulating layer has a plurality of edges reaching the terminal electrode on the side of the terminal electrode that is close to the portion exposed from the insulating layer. A through-hole is formed, and the protruding electrode is located on the edge so as to partially cover the edge, and is connected to the terminal electrode through the plurality of through-holes.

  In the electronic component according to the present invention, the terminal electrode and the protruding electrode are connected to each other through the plurality of through holes formed at the edge of the insulating layer while sandwiching the edge of the insulating layer. Thereby, the joint strength between the terminal electrode and the protruding electrode can be improved.

  Preferably, the portion exposed from the insulating layer of the terminal electrode is surrounded by the edge of the insulating layer, and a plurality of through holes are formed along the periphery of the portion exposed from the insulating layer of the terminal electrode. Yes. In this case, the length of the edge becomes relatively long while ensuring the area of the portion exposed from the insulating layer of the terminal electrode. When the length of the edge portion is increased, the number of through holes formed in the edge portion can be increased, and the bonding strength between the terminal electrode and the protruding electrode can be further improved.

  Preferably, the insulating layer is made of baked glass. In this case, when the insulating layer is formed by baking the glass, the glass contracts and becomes melted so that the surface tension acts, so that a plurality of through holes are formed at the edge of the insulating layer. . As a result, a plurality of through holes can be easily formed.

  ADVANTAGE OF THE INVENTION According to this invention, the electronic component which can improve the joint strength of a terminal electrode and a protruding electrode can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  With reference to FIG.1 and FIG.2, the structure of the electronic component 1 which concerns on this embodiment is demonstrated. FIG. 1 is a schematic diagram for explaining a cross-sectional configuration of an electronic component according to the present embodiment. FIG. 2 is a plan view showing the electronic component according to the present embodiment. In FIG. 1, hatching is omitted for easy viewing of the drawing.

  The electronic component 1 includes a base 3, a terminal electrode 5, an insulating layer 7, and a protruding electrode 9.

  The base 3 has a plurality of stacked functional layers and a plurality of internal electrodes 11. For example, the plurality of internal electrodes 11 are arranged to face each other with the functional layer interposed therebetween. In the actual electronic component 1, each functional layer is integrated so that the boundary between the functional layers cannot be visually recognized. Here, the functional layer is a layer made of a material having a desired function, for example, a layer made of a material having voltage nonlinear characteristics (so-called varistor characteristics), a layer made of a dielectric material, or a magnetic material. A layer made of a nonmagnetic material, a layer made of an electrically insulating material, or the like.

  Each functional layer is composed of, for example, a sintered body of a ceramic green sheet containing ceramic. Each internal electrode 11 is composed of a sintered body of conductive paste. When the functional layer is a functional layer that exhibits varistor characteristics, it can be made of a ceramic material (semiconductor ceramic) containing ZnO as a main component. This ceramic material further contains at least one element selected from the group consisting of rare earths and Bi, and Co as additives.

  A plurality of terminal electrodes 5 are arranged on the outer surface 4 of the substrate 3 (only one terminal electrode 5 is shown in FIGS. 1 and 2), and a corresponding internal electrode among the plurality of internal electrodes 11. The electrode 11 is electrically and physically connected. The terminal electrode 5 is made of, for example, Pt, Pd, Ag, an Ag—Pd alloy, Cu, Ni, Au, or the like. The terminal electrode 5 is formed, for example, by applying a conductive paste containing conductive metal powder and glass frit to the outer surface 4 of the substrate 3 and baking it. If necessary, a plating layer may be formed on the baked electrode 5. As conductive metal powder, the metal powder which has the metal particle mentioned above as a main component can be used.

  The insulating layer 7 is made of baked glass and is disposed so as to straddle the base 3 and the terminal electrode 5. The insulating layer 7 has a function of ensuring electrical insulation between the terminal electrodes 5 and a function of protecting the substrate 3. The insulating layer 7 is formed on the base 3 and the terminal electrode 5 so that at least a part of the terminal electrode 5 is exposed. Examples of the glass used for the insulating layer 7 include Zn—Bi glass, Si—Zn glass, Si—Al glass, Si—B glass, and Pb—Si glass.

  In the insulating layer 7, a plurality of through holes 13 penetrating the insulating layer 7 and reaching the terminal electrode 5 are formed in the edge portion 8 of the terminal electrode 5 on the side close to the portion 6 exposed from the insulating layer 7. . In this embodiment, the portion 6 exposed from the insulating layer 7 of the terminal electrode 5 is surrounded by the edge 8 of the insulating layer 7, and the through hole 13 is the portion exposed from the insulating layer 7 of the terminal electrode 5. A plurality are formed along the periphery of 6.

  When the material of the insulating layer 7 is glass, the insulating layer 7 provides the glass paste containing the glass component described above, an organic binder, and a glass paste mixed with an organic solvent to the outer surface 4 of the substrate 3 and the terminal electrode 5, It can be formed by baking. In this case, since the glass shrinks and enters a molten state to exert surface tension, a plurality of through holes 13 are naturally formed in the insulating layer 7. In particular, since the edge portion 8 is thinned by melting of the glass, the through hole 13 is easily formed.

  As a material of the insulating layer 7, a resin or the like can be used besides glass. When resin is used as the material of the insulating layer 7, the through hole 13 can be formed by printing and curing the resin using a plate making having a pattern corresponding to the through hole 13.

  The protruding electrode 9 is made of solder and is disposed on the terminal electrode 5. The protruding electrode 9 is electrically and physically connected to the portion 6 exposed from the insulating layer 7 of the terminal electrode 5, and a part of the protruding electrode 9 is located on the edge 8 so as to cover the edge 8. . A portion of the protruding electrode 9 located on the edge 8 is electrically and physically connected to the terminal electrode 5 through the plurality of through holes 13. The edge 8 is sandwiched between the protruding electrode 9 and the terminal electrode 5.

  The protruding electrodes (so-called bump electrodes) 9 can be formed by a printing method. That is, after the solder paste is screen-printed on the portion 6 exposed from the insulating layer 7 of the terminal electrode 5 using a metal mask in which an opening corresponding to the portion 6 exposed from the insulating layer 7 of the terminal electrode 5 is formed. The protruding electrode 9 can be formed by heating and melting. At this time, the molten solder paste spreads over the edge portion 8 and enters the through hole 13. Thereby, the protruding electrode 9 and the terminal electrode 5 are connected through the through hole 13. Although glass and solder are poor in wettability with each other, the thickness of the edge 8 may be thin, and it is considered that the molten solder paste spreads on the edge 8 due to its own weight or the like.

  The protruding electrode 9 can be formed not only by a printing method but also by a vapor deposition method or a plating method.

  As described above, in the present embodiment, the protruding electrode 9 is not only connected to the portion 6 exposed from the insulating layer 7 of the terminal electrode 5, but also the edge 8 of the insulating layer 7 is connected to the terminal electrode 5. In addition to being sandwiched, the terminal electrode 5 is connected through a plurality of through holes 13 formed in the edge 8 of the insulating layer 7. Thereby, the joint strength between the terminal electrode 5 and the protruding electrode 9 can be improved.

  In this embodiment, the portion 6 exposed from the insulating layer 7 of the terminal electrode 5 is surrounded by the edge 8 of the insulating layer 7, and the through hole 13 is exposed from the insulating layer 7 of the terminal electrode 5. A plurality of portions are formed along the periphery of the portion 6. Thereby, the length of the edge 8 becomes relatively long while ensuring the area of the portion 6 exposed from the insulating layer 7 of the terminal electrode 5. If the length of the edge portion 8 is increased, the number of through holes 13 formed in the edge portion 8 can be increased, and the bonding strength between the terminal electrode 5 and the protruding electrode 9 can be further improved.

  In the present embodiment, the insulating layer 7 is made of baked glass. In this case, the plurality of through holes 13 can be easily formed. Further, as described above, since the plurality of through holes 13 are naturally formed when the insulating layer 7 is formed, the shape thereof is distorted. For this reason, when the glass enters the through hole 13 and is cured, an anchor effect is generated, and it is considered that the bonding strength between the terminal electrode 5 and the protruding electrode 9 is further improved.

  The preferred embodiments of the present invention have been described above. However, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  For example, in this embodiment, the portion 6 exposed from the insulating layer 7 of the terminal electrode 5 is surrounded by the edge 8 of the insulating layer 7. However, the present invention is not limited to this, and the insulating layer of the terminal electrode 5 is not limited thereto. The portion 6 exposed from 7 may not be surrounded by the edge 8 of the insulating layer 7.

  The present invention can be applied to various electronic components such as varistors, capacitors, and inductors.

It is a schematic diagram for demonstrating the cross-sectional structure of the electronic component which concerns on this embodiment. It is a plane which shows the electronic component which concerns on this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electronic component, 3 ... Base | substrate, 4 ... Outer surface, 5 ... Terminal electrode, 6 ... Part exposed from an insulating layer, 7 ... Insulating layer, 8 ... Edge part, 9 ... Projection electrode, 11 ... Internal electrode, 13 ... through hole.

Claims (2)

A substrate;
A terminal electrode formed on the substrate;
An insulating layer formed on the base and the terminal electrode so that at least a part of the terminal electrode is exposed;
Formed on the terminal electrode, and a protruding electrode made of solder, and
The insulating layer is made of glass obtained by baking a glass paste applied onto the base body and the terminal electrode, and the thickness of the edge of the terminal electrode adjacent to the portion exposed from the insulating layer is A plurality of through-holes reaching the terminal electrode are formed in the edge portion due to the surface tension in the contraction and melting state of the glass, while being thinned by melting of the glass,
The protruding electrode is positioned on the edge so that a part thereof covers the edge, and is connected to the terminal electrode through the plurality of through holes. The portion exposed from the insulating layer of the terminal electrode is surrounded by the edge of the insulating layer,
2. The electronic component according to claim 1, wherein a plurality of the through holes are formed along a periphery of the portion exposed from the insulating layer of the terminal electrode.

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