JP2007067026A - Electronic component and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the variation of the size of an external electrode in a minute electronic component. <P>SOLUTION: When forming a ground electrode by applying conductive paste on the electronic component, there is previously formed a groove of a predetermined shape in an electronic component element on an application side, and the conductive paste is applied so as to be filled in the groove. It is possible to suppress the variation of the size of the external electrode in the minute electronic component by such an extremely simplified operation. More specifically, the applied conductive paste is fluidized by making use of the surface tension of the conductive paste itself, affinity possessed by a chip surface or of the surface tension and affinity, and even if the tip of the conductive paste is curved and reaches the groove with a time difference, the paste accumulates in the groove successively from the fraction thereof that previously reaches the groove and fills the groove. It is noted that the conductive paste is prevented from spreading beyond the groove until the whole of the groove is filled, so that it is possible to suppress a moon shape as effective as possible without causing a curved edge as in conventional technologies. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for forming an external electrode for a microelectronic component.

  Conventionally, various electronic components having external electrodes at both ends of a chip exist, and as a method for forming external electrodes on the chip, a dip method, a roller method, or the like is known.

  In the dip method, the end surface portion of the chip 101 is pressed against the conductive paste 103 placed in the container 102 as shown in FIG. 1, and in the roller method, the conductive paste 103 is applied by the application roller 104 as shown in FIG. It is applied to the end surface portion of the chip 101.

  As the conductive paste 103, a paste containing a conductive metal such as Ag, Ag / Pd, Cu, or Ni as a main component and added with a glass frit, a resin binder, and a solvent is used.

  Then, after forming the base electrode by applying the conductive paste 103 by the method as described above, predetermined baking (500 ° C. or higher) is performed, and plating such as Ni is applied to provide solder resistance at the time of mounting. The film is applied as an underlayer, and a plating film such as Sn is further applied to provide good wettability with the substrate to form an external electrode.

  In JP-A-10-83935, even a so-called dip coating in which both ends of a capacitor element are immersed in a conductive paste and a conductive paste is applied can form a gap with a certain width with high accuracy. In addition, a technique is disclosed in which the diameter of the insulating coating is not increased and a high capacitance value is obtained. Specifically, when forming a step part that falls on both sides of the gap part of the capacitor body, and applying the conductive paste by dip coating, the application of the conductive paste stops at that part due to the drop of the step part. did. And, by attaching the conductor film to this step portion, not only the edge of the electrode made of the conductor film is abutted across the gap, but the counter electrode is formed in the step portion of the electrode, A higher capacitance value can be obtained. Further, when a resin is applied to the insulating coating to form an insulating coating, the resin enters the stepped portion, so that the outer diameter of the insulating clothing does not become extremely large. In addition, such a step part does not assume the case where an external electrode is formed in the edge part of a capacitor | condenser element, and does not target microcomponents.

Japanese Patent Laid-Open No. 5-283210 discloses a technique for improving the exterior yield and the electrical property yield associated therewith by preventing the insulating paint from flowing out. Specifically, first, a powder made of ZnO, a valence control agent and a sintering aid and granulated by adding polyvinyl alcohol is pressure-molded with a mold, and after debinding, 1200 ° C. in the atmosphere. Bake for 2 hours. Next, a groove is formed in the obtained chip-shaped ceramic by an outer peripheral polishing machine, and an epoxy insulating coating is applied to the central portion of the side surface in a strip shape having a thickness of 50 μm around the ceramic and dried at 200 ° C. Form an insulating paint layer. Next, a Ni conductive paint layer having a thickness of 10 μm is formed on a pair of opposing end faces of the chip-like ceramic, and a Cu plating layer having a thickness of 2 to 3 μm is formed using Rossel salt Cu on a portion where no exterior material is applied. Further, a 2 to 3 μm Ni plating layer and a 1 to 2 μm Sn / Pb plating layer are formed on the surface. The groove of this publication is intended to prevent the outflow of the insulating paint, and is not intended for minute parts.
JP-A-10-83935 Japanese Patent Laid-Open No. 5-283210

  Electronic components are always required to be miniaturized. For example, in the field of multilayer capacitors, the size is 1005 (length 1.0 mm × width 0.5 mm), 0603 (0.6 mm × 0.3 mm). Things are in circulation, and recently, 0402 (0.4 mm × 0.2 mm) is on the market. However, problems arise when trying to manufacture electronic components uniformly by the dip method. That is, as shown in FIG. 3, due to the surface tension of the conductive paste itself or the physical properties such as the affinity and hydrophobicity of the chip 101, the edge portion 101a of the external electrode 105 after the plating process is along the surface of the chip 101. A shape (moon shape) that gently spreads in the center so as to draw an arc occurs, and the boundary between the chip 101 and the external electrode 105 is greatly curved. For this reason, the conductive paste is applied with the intention of the widths d1 and d2 of the edge portion 101a of the external electrode 105 in order to secure the base electrode design dimension d3 related to the area necessary for electrode formation.

  However, the width d1 or d2 of the edge portion 101a of the external electrode 105 may occupy more than half of the base electrode design dimension d3, which may cause variations in the external electrode dimension and the inter-electrode dimension. There is a risk of causing a mounting failure such as a short circuit failure or chip standing (Manhattan phenomenon). Such a problem becomes a more serious problem in minute parts such as the 0603 shape and the 0402 shape.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for suppressing variation in the dimensions of external electrodes in a minute electronic component such as a 0603 shape or a 0402 shape.

  The electronic component according to the present invention includes an electronic component element and an external electrode formed on the surface of the electronic component element. And the said electronic component element has a groove part, and the conductive paste used when forming the said external electrode is filled with the said groove part. By providing the groove filled with the conductive paste, it is possible to prevent the appearance of the edge portion 101a that draws an arc as shown in FIG.

  The depth of the groove is set to d / 2 to d (μm) with respect to the average film thickness d (μm) in a specific portion of the external electrode formed in the non-groove forming portion of the electronic component element. May be. It becomes possible to more reliably suppress variations in external electrode dimensions.

  Furthermore, the electronic component element may have a structure for a multilayer ceramic capacitor.

  Moreover, you may form so that the said groove part may become a boundary with an external electrode in the surface of an electronic component element. Since the groove portion suppresses the expansion of the external electrode, the groove portion forms a boundary between the portion where the external electrode is formed and the other portion.

  An electronic manufacturing component manufacturing method according to the present invention includes a step of forming a groove on a surface of an electronic component element, a step of applying a conductive paste to the surface of the electronic component element, and plating the conductive paste to externally Forming an electrode. And the said groove part is formed in the position used as the boundary with an external electrode in the surface of an electronic component element. The electronic component described above is configured.

  Alternatively, the conductive paste may be a conductive paste having a viscosity adjusted to 1 Pa · s to 90 Pa · s (10 rpm).

  According to the present invention, it is possible to suppress variation in the dimensions of external electrodes in a minute electronic component.

[Outline of Embodiment of the Present Invention]
When a conductive paste is applied to an electronic component to form a base electrode, a groove having a predetermined shape is formed in advance on the electronic component element to be applied, and the conductive paste is applied so as to fill the groove. With such an extremely simple operation, variations in the dimensions of the external electrodes can be suppressed in a minute electronic component. That is, the applied conductive paste flows using the surface tension of the conductive paste itself, the affinity of the chip surface, or the surface tension and affinity, and the tip of the conductive paste is curved, Even if the groove is reached with a time difference, the conductive paste that has reached first gradually accumulates in the groove and fills the groove. Since the conductive paste does not spread beyond the groove until all of the grooves are filled, a curved edge is not generated as in the conventional case, and the moon shape can be suppressed as much as possible.

  Therefore, according to the electronic component having a groove as described above, it is possible to avoid the rounding of the edge portion with a simple operation just by adjusting the amount of the conductive paste used, and there is no variation in the dimensions of the external electrode. The structure can be obtained.

  That is, the application surface after applying the conductive paste has a linear boundary with the chip, and the boundary between the external electrode and the chip can be formed into a straight line by plating the surface. It becomes like this.

  Further, according to the manufacturing method as described above, the external electrode dimensions and the dimensional variations between the electrodes can be suppressed, and in particular, good dimensional accuracy can be realized even for minute parts such as the 0603 shape and 0402 shape. Therefore, it is possible to avoid the cause of mounting failure such as short circuit failure between electrodes and chip standing (Manhattan phenomenon).

  In particular, if the manufacturing method described above is applied to a multilayer capacitor, it becomes possible to manufacture a micropart with desired capacitance characteristics and durability.

[Configuration of electronic component according to this embodiment]
An electronic component according to an embodiment of the present invention is an electronic component comprising an electronic component element and an external electrode formed on the surface of the electronic component element. For example, a multilayer capacitor, an inductor, and a choke coil And various electronic parts such as varistors and thermistors. As will be described later, it is particularly recommended to configure as a multilayer ceramic capacitor or a multilayer inductor from the viewpoint of need characteristics for micro parts, stability of capacitance, and stabilization of deflection strength.

  The material for forming the electronic component according to the present embodiment can be variously selected according to the aspect of the electronic component, and a known material can be used. For example, in the case of a multilayer ceramic capacitor, barium titanate or the like can be used as an electronic component element material. Examples of the conductive paste of the base electrode material for the external electrode include, for example, a paste mainly composed of a conductive metal such as Ag, Ag / Pd, Cu, Ni, and prepared with a glass frit, a resin binder, and a solvent. it can. Further, examples of the plating solution for the external electrode include a silver plating solution. However, these materials are variously changed according to the electronic component and are not particularly limited.

  FIG. 4A shows a side view of the electronic component 10 according to the present embodiment, and FIG. 4B shows a top view of the electronic component 10. The electronic component 10 includes an approximately rectangular parallelepiped electronic component element 1 and an external electrode 2 formed on the surface of the electronic component element 1. In the electronic component element 1, a groove 1a is provided at a position away from the left end by a predetermined distance so as to go around the electronic component element 1, and the groove is formed at a position away from the right end by a predetermined distance. 1 b is provided so as to go around the electronic component element 1. And in the groove | channels 1a and 1b, the boundary with the external electrode 2 in the surface of the electronic component element 1 is formed. That is, the grooves 1a and 1b are filled with a conductive paste, and a plating surface (a part of the external electrode) on which the conductive paste is plated is formed at the positions of the grooves 1a and 1b. No plating film is formed.

  In the case where the electronic component 10 is a multilayer ceramic capacitor, the electronic component element 1 itself is the same as the conventional one except for the grooves 1a and 1b. Next, the grooves 1a and 1b will be described with reference to FIGS.

  FIG. 5 is a perspective view of the electronic component element 1. As shown in FIG. 5, the shapes of the grooves 1 a and 1 b are rectangular and are formed at positions separated from the left and right ends of the electronic component element 1 by w. More specifically, the grooves 1a and 1b are provided to intersect the four long sides of the electronic component element 1 at right angles so as to go around four side surfaces including the four long sides. The groove 1 a is formed at a position separated from the left end of the electronic component element 1 by a width w, and the groove 1 b is formed at a position separated from the right end of the electronic component element 1 by a width w. The positions of the grooves 1a and 1b are variously set depending on the type and application of the electronic component. The shape of the grooves 1a and 1b is not limited to a rectangle, but may be an inverted triangle, an ellipse, or a lower half of a circle.

  Next, in order to explain the depth of the grooves 1a and 1b, etc., FIG. 6 shows a cross-sectional view (partial) taken along line AA ′ of FIG. The depth X of the grooves 1a and 1b is adjusted so that the flow of the applied conductive paste can be stopped. That is, it is possible to suppress the generation of a curved edge until the conductive paste flows and completely fills the grooves 1a and 1b, and when the plating for the external electrode is applied, the plating does not vary in size. It is recommended to define that a film can be formed.

  As shown in FIG. 6, the depth X (μm) of the groove 1b is d / 2 to d (μm) when the average film thickness of the conductive paste formed in the non-groove forming part is d (μm). It is preferable that If the depth X of the grooves 1a and 1b is shallower than d / 2 (μm), even if an attempt is made to form the external electrode 2 up to the dimensional position of the external electrode 2, the external electrode 2 cannot be applied successfully in operation, When a conductive paste prepared to have a viscosity (preferably 10 Pa · s to 90 Pa · s, particularly 10 Pa · s to 80 Pa · s (10 rpm) is used for the conductive paste) The paste flows out over the groove, and moon shape is likely to occur. In order to avoid such a problem with viscosity, the viscosity adjustment of the conductive paste becomes complicated. On the other hand, when the depth X of the grooves 1a and 1b is deeper than the average film thickness d (μm), the strength of the electronic component element 1 is reduced. In particular, since the flexural strength rapidly decreases to about 1/5, there arises a problem that durability is likely to deteriorate. In addition, the amount of the conductive paste used increases, and the performance as an electronic component is also affected. In particular, the effect may be significant in a minute component.

  In addition, the average film thickness in this Embodiment means the film thickness of the most part of the external electrode 2 formed with an electrically conductive paste, and does not mean the average value of the whole actual film thickness. If it demonstrates in detail using FIG. 6, the average film thickness d in this Embodiment is an average thickness of most places Z which became flat when apply | coating a conductive paste. For example, when the average film thickness d of the conductive paste is 20 μm, the groove depth is preferably adjusted to 10 to 20 μm.

  The width Y (μm) of the grooves 1a and 1b can be appropriately selected depending on the viscosity of the conductive paste, the size of the electronic component 10, and the like. However, it is recommended that the width Y is X / 2 to X / 3 (μm) with respect to the depth X (μm). If the width is larger than X / 2 (μm), it is difficult to design as a micro component. As a result, the amount of conductive paste used increases too much. On the other hand, if the width is less than X / 3 (μm), the conductive paste may overflow beyond the grooves 1a and 1b.

  In the electronic component element 1 according to the present embodiment, the conductive paste can be applied stably and uniformly without the edge of the external electrode 2 being curved and protruding from a predetermined position as in the prior art. Therefore, the state of the coating film formed on the conductive paste is also stable, and it is possible to reduce the amount of the conductive paste and plating solution that protrudes, and to avoid high-quality variations by avoiding dimensional variations among products. Product will be obtained.

[Method of manufacturing electronic component according to the present embodiment]
The electronic component element 1 itself of the electronic component according to the present embodiment can be basically manufactured by a known procedure. That is, a method of stacking and cutting ceramic green sheets in which internal electrodes are formed in advance can be employed.

  The grooves 1a and 1b of the electronic component 10 in the present embodiment can be formed using various methods, but in the present embodiment, the individual electronic component elements 1 are cut by cutting the ceramic green sheet. In order to reduce the lead time, it is recommended to simultaneously form the grooves 1a and 1b.

  Next, a method for cutting the ceramic green sheet will be described with reference to FIGS. FIG. 7A shows the upper surface of a ceramic green sheet 4 for a multilayer ceramic capacitor, for example, and this ceramic green sheet 4 is the same as the conventional one. FIG. 7B shows an enlarged view of the portion 5 in FIG. In FIG. 7B, the hatched portion represents a region for one electronic component element 1. Lines for grooves 1a and 1b are also shown to show the positional relationship. However, the groove 1a and the groove 1b are not formed at this stage. In addition, on the ceramic green sheet 4, a virtual vertical line 6 (one-dot chain line) and a virtual horizontal line 7 (two-dot chain line) for cutting are formed in advance, and by cutting along the virtual vertical line 6, the following Then, the grooves 1a and 1b are formed, and the electronic component element 1 is separated by cutting along the virtual horizontal line 7 as usual.

  The state seen from the direction of the arrow C in FIG. 7B is shown in FIG. In this way, after the ceramic green sheets 4 are laminated to form the laminated body 4 ′, the laminated body 4 ′ is placed on the compression molding die 14 having the groove forming convex portions 13. The groove forming convex portion 13 is approximately a rectangular parallelepiped, and its height is determined according to the depth X described above and the width according to the width Y described above. In FIG. 7C, the compression molding die 14 is disposed only on the lower surface of the laminate 4 ′. However, the compression molding die 14 having the similar groove forming convex portion 13 on the upper surface is inverted. In addition, if they are arranged at the same position and compressed from above and below, a laminate 4 ′ as shown in FIG. 7 (d) is formed. That is, the grooves 1a and 1b are formed on the upper and lower sides. However, no groove is formed on the vertical side surface.

  If a flat compression molding die is disposed on the upper surface and a compression molding die 14 having a groove forming convex portion 13 is disposed on the lower surface and compressed up and down, as shown in FIG. In addition, a laminated body 4 ″ is formed in which grooves 1a and 1b are formed only on the lower surface. The subsequent steps for the laminated body 4 ″ will be described later.

  Next, a method for forming the grooves 1a and 1b on the vertical side surface of the electronic component element 1 will be described. In the present embodiment, from the viewpoint of improving work efficiency, a cutter 8 having a specially shaped blade 9 is used so that grooves 1a and 1b are formed on the vertical side surface of the electronic component element 1 simultaneously with cutting.

  FIG. 8A shows the outer shape of the blade 9 of the cutter 8. The blade 9 is provided with a plurality of groove forming convex portions 9a so as to match the interval between the grooves 1a and 1b. The height of the groove forming convex portion 9a from the blade 9 is determined according to the depth X described above and the width according to the width Y described above.

  Then, the blade 4 is aligned with the virtual vertical line 6 shown in FIG. This is shown in FIGS. 8B and 8C. FIG. 8B shows a side sectional view along the groove 1a or 1b when cut by the cutter 9. FIG. The laminated body 4 ′ is divided into left and right by the blade 9 of the cutter 8, and the groove 1 a or 1 b is formed on the side surface in the longitudinal direction of the laminated body 4 ′ by the groove forming convex part 9 a of the blade 9. In the laminate 4 ′, the upper and lower grooves 1 a or 1 b already formed by the groove forming protrusions 13 are also indicated by dotted lines.

  FIG. 8C shows a state viewed from the right side surface by removing the right side stack 4 ′ from the stack 4 ′ shown in FIG. 8B. In FIG. 8C, the removed laminate 4 ′ is indicated by a dotted line. As can be seen from FIG. 8C, the interval between the groove forming convex portions 9a is not necessarily equal, and the interval between the groove 1a and the groove 1b is different from the interval between the grooves 1a and 1b in one electronic component element 1. Since there are two types of gaps 1a and 1b between the electronic component elements 1, the gaps between the groove-forming convex portions 9a are set so as to match them.

  In the case where the groove 1a or 1b is formed only on the lower surface as in the laminate 4 ″ in FIG. 7E, a cutter 15 as shown in FIGS. 9A and 9B is used. 8A is a side view seen from the same direction as in FIG.8B, and the cutter 15 has a groove forming convex portion 17 for forming the grooves 1a and 1b. It is not formed only on the blade 9 as in the groove forming convex portion 9a shown in FIGS. 8A to 8C, but is also formed on the base portion of the blade 16 and the cutter 15. The groove-forming convex portion 17 provided in is used for forming the grooves 1a and 1b on the vertical side surface of the laminated body 4 ″. Further, the groove forming convex portion 17 formed on the base portion of the cutter 15 is used to form the grooves 1a and 1b on the upper surface of the laminated body 4 ″. That is, in the state as shown in FIG. If the cutter 15 shown in FIGS. 9A and 9B is used, the grooves 1a and 1b are formed at a time on the upper surface and both side surfaces.

  As described above, the grooves 1a and 1b are formed simultaneously with the cutting of the green sheet 4, and the working efficiency is improved.

  When the green sheet 4 is cut using the cutter 8 or 15, as shown in FIGS. 10A and 10B, a point 11 for alignment in advance at a predetermined position of the green sheet 4. The point 11 is detected by a detector 12 such as an infrared ray provided at a corresponding position of the cutter 8 or 15. Thereby, the blade 9 of the cutter 8 or the blade 16 of the cutter 15 is aligned with the virtual vertical line 6 and the green sheet 4 is appropriately cut. Then, the groove forming convex portion 9 a provided on the blade 9 of the cutter 8 or the groove forming convex portion 17 provided on the blade 16 of the cutter 15 is previously formed by the groove forming convex portion 13 of the compression molding die 14. The green sheet 4 is cut so as to be connected to the grooves 1a and 1b.

  By using such a cutter 8 or cutter 15, it is possible to obtain a component with good yield and excellent durability. In particular, when a multilayer ceramic capacitor is manufactured, it can be manufactured with a high yield while maintaining a stable capacitance.

  Note that this embodiment can be applied to various electronic components, and in particular, its use is not limited as long as it has external electrodes at both ends of the chip. For example, a multilayer ceramic capacitor, an inductor, a common mode choke coil, an array, etc. It can be applied to various uses. In particular, in a micro component such as the 0603 shape or the 0402 shape, a short circuit failure between electrodes and a mounting failure such as chip standing (Manhattan phenomenon) can be suppressed as much as possible.

  Although the embodiment of the present invention has been described above, the present invention is not limited to this. In particular, for example, any device used for manufacturing may be used as long as it can manufacture an electronic component having the above-described structure.

It is a figure for demonstrating the conductive paste application | coating method of a prior art. It is a figure for demonstrating the conductive paste application | coating method of a prior art. It is a side view of the electronic component in a prior art. (A) is a side view of the electronic component which concerns on this Embodiment, (b) is the top view. It is a perspective view of the electronic component element of the electronic component which concerns on this Embodiment. It is sectional drawing in the AA 'surface in FIG.4 (b). (A) is a top view of the green sheet, (b) is an enlarged view of a part of the green sheet, (c) a side view of (b), (d) a side view of the laminate 4 ′, (e) a laminate 4 ″. FIG. (A) is a perspective view of the blade of the cutter used for a cutting | disconnection, (b) is sectional drawing at the time of cut | disconnecting a green sheet with a cutter, (c) It is a side view of (a). (A) is a side view of the cutter used for a cutting | disconnection, (b) is a figure which shows the top view of a cutter. (A) And (b) is a figure for demonstrating the mechanism which performs position alignment of a cutter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic component element 2 External electrode 1a, 1b Groove 4 Green sheet 4 ', 4 "Laminate

Claims (6)

An electronic component element;
An external electrode formed on the surface of the electronic component element;
Comprising
The electronic component element comprises a groove,
An electronic component in which the groove portion is filled with a conductive paste used in forming the external electrode.   The depth of the groove is d / 2 to d (μm) with respect to an average film thickness d (μm) in a specific portion of the external electrode formed in a non-groove forming portion of the electronic component element. 1 is an electronic component.   The electronic component according to claim 1, wherein the electronic component element has a structure for a multilayer ceramic capacitor. The electronic component according to any one of claims 1 to 3, wherein the groove serves as a boundary with the external electrode on the surface of the electronic component element. Forming a groove on the surface of the electronic component element;
Applying a conductive paste to the surface of the electronic component element;
Forming an external electrode by plating on the conductive paste;
Including
The method of manufacturing an electronic component, wherein the groove is formed at a position that is a boundary with the external electrode on the surface of the electronic component element.   6. The method of manufacturing an electronic component according to claim 5, wherein the conductive paste is a conductive paste having a viscosity of 1 Pa · s to 90 Pa · s (10 rpm).

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