JP4880494B2 - Chip-type solid electrolytic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a chip-type solid electrolytic capacitor and a method for manufacturing the same.

  In general, by attaching an anode lead wire to an anode element made of a valve metal, and sequentially forming a dielectric oxide film, a solid electrolyte layer, and a cathode lead layer made of a carbon layer and a silver layer on the surface of the anode element After forming the capacitor element and coating the capacitor element with the powder sheathing resin, a part of the cathode lead layer is exposed to form a cathode metal layer, and a part of the anode lead-out line is further exposed to form the anode. A chip-type solid electrolytic capacitor manufactured by forming a metal layer is known (see, for example, Patent Document 1).

  The cathode metal layer and the anode metal layer of the chip-type solid electrolytic capacitor described in Patent Document 1 are formed by applying a conductive paste.

Patent Document 2 discloses a chip capacitor in which a cathode metal layer and an anode metal layer are formed by immersing a chip body in a conductive paste.
Japanese Patent Publication No. 61-32807 JP-A-6-260377

  Here, when manufacturing a chip-type solid electrolytic capacitor, after applying a conductive paste as described in the above-mentioned Patent Document 1 or forming the above-mentioned patent in order to form a cathode metal layer and an anode metal layer. After being immersed in the conductive paste as described in Document 2, it is allowed to stand at room temperature for a predetermined time. At this time, the conductive paste spreads over the surface of the powder-coated resin with the surface tension over time. Thereby, an individual difference will arise in the shape of a cathode metal layer and an anode metal layer. Therefore, the board mounting performance is significantly lowered, and problems such as chip standing occur in the reflow process for soldering to the board.

  Accordingly, an object of the present invention is to provide a chip-type solid electrolytic capacitor capable of improving the dimensional accuracy of the cathode metal layer and the anode metal layer and improving the substrate mounting performance, and a method for manufacturing the same.

The chip-type solid electrolytic capacitor of the present invention includes an anode element made of a valve action metal, an anode lead wire attached to the anode element, a dielectric oxide film sequentially formed on the surface of the anode element, and a solid electrolyte. A capacitor element having a layer and a cathode lead layer;
A powder sheathing resin that coats the capacitor element such that a part of the cathode lead-out layer and the anode lead-out line are exposed, and
A cathode metal layer connected to a portion of the cathode lead layer exposed from the powder sheathing resin and formed on the surface of the powder sheathing resin by a fluid material;
A chip-shaped solid, which is connected to a portion of the anode lead-out line exposed from the powder sheathing resin and has an anode metal layer formed on the surface of the powder sheathing resin by a fluid material It is an electrolytic capacitor.
And it further comprises two linear electrodes formed of a conductive material on the surface of the powder sheathing resin, and the two linear electrodes are used to connect the powder sheathing resin to the mounting substrate. An opposing surface is connected to the cathode vicinity region connected to the portion where the cathode lead-out layer is exposed, and is connected to the portion where the anode lead-out line is exposed, and the anode vicinity region is not connected to the cathode vicinity region; It is divided into an intermediate region not connected to either the portion where the cathode lead layer is exposed or the portion where the anode lead-out line is exposed (first invention).

In the chip-type solid electrolytic capacitor of the present invention, the linear electrode is preferably linear (second invention).

In the method for manufacturing a chip-type solid electrolytic capacitor of the present invention, an anode lead wire is attached to an anode element made of a valve metal, and a dielectric oxide film, a solid electrolyte layer, and a cathode lead layer are provided on the surface of the anode element. A capacitor element forming step of sequentially forming a capacitor element; a covering step of covering the capacitor element with a powder sheathing resin;
A first removing step of removing a part of the powder sheathing resin so that a part of the cathode lead layer is exposed;
A second removal step of removing a part of the powder sheathing resin so that a part of the anode lead-out line is exposed;
A cathode metal layer forming step of forming a cathode metal layer connected to the portion exposed in the first removal step of the cathode lead layer with a material having fluidity;
Manufacturing of a chip-type solid electrolytic capacitor comprising an anode metal layer forming step of forming an anode metal layer connected to a portion exposed in the second removal step of the anode lead-out line with a material having fluidity Is the method.
And before performing the said cathode metal layer formation process and the said anode metal layer formation process, the linear electrode formation process which forms two linear electrodes with the material which has electroconductivity on the surface of the said powder exterior resin. and further comprising, by the linear electrodes of the two formed in the linear electrode forming step, the surface facing the mounting board of the powder exterior resin, leading to a portion the cathode lead-out layer is exposed A region near the cathode, connected to a portion where the anode lead-out line is exposed, and a region near the anode not connected to the cathode vicinity region, a portion where the cathode lead-out layer is exposed, and the anode lead-out line are It is divided into intermediate regions that are not connected to any of the exposed portions (third invention).

Furthermore, in the manufacturing method of the Chip solid electrolytic capacitor of the present invention, in the linear electrode forming step, a spray method, an ink jet method, a dispenser method, and at least said linear electrodes in any one method of the transfer method It may be formed (fourth invention).

According to the first and third inventions, the linear electrode can prevent the fluid material that becomes the cathode metal layer and the anode metal layer from spreading on the surface of the powder-coated resin by surface tension. Therefore, the dimensional accuracy of the cathode metal layer and the anode metal layer is improved. Therefore, the board mounting performance can be improved.
Moreover, since the application levels of the cathode metal layer and the anode metal layer can be fixed, the ease of mounting work on the mounting board is also improved.

  According to the second invention, the edges of the cathode metal layer and the anode metal layer can be linear.

According to the fourth invention, the linear electrode can be easily formed by an existing method.

  A preferred embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view of the chip-type solid electrolytic capacitor according to the present embodiment. A chip-type solid electrolytic capacitor (hereinafter abbreviated as “capacitor”) 10 of the present embodiment has a substantially rectangular parallelepiped shape as a whole, and covers capacitor element 1 and capacitor element 1 as shown in FIG. A powder sheathing resin 7. 1 is a mounting surface 9 that faces the mounting board when mounted on a mounting board (not shown).

  Capacitor element 1 includes anode body element 2 of a porous sintered body having a substantially rectangular parallelepiped shape, anode lead wire 3 welded to one end side in the longitudinal direction of anode body element 2 (left side in FIG. 1), anode body It has a dielectric oxide film 4 sequentially formed on the surface of the element 2, a solid electrolyte layer 5 made of manganese dioxide, and a cathode lead layer 6. The cathode lead layer 6 is composed of a carbon layer 6a and a silver layer 6b. In the present embodiment, tantalum, which is a valve metal, is used as anode element 2.

  As shown in FIG. 1, the powder sheathing resin 7 has the anode lead-out wire 3 drawn to the outside and a part of the surface of the cathode lead-out layer 6 (that is, the silver layer 6b) in the capacitor element 1, more specifically, Capacitor element 1 is covered so that a part of the side opposite to the side where anode lead-out line 3 is attached (the right side in FIG. 1) is exposed.

  Further, the capacitor 10 includes a cathode metal layer 11 connected to the exposed portion of the cathode lead layer 6, that is, connected to the silver layer 6 b, and an anode metal layer 12 connected to the anode lead-out line 3. Is formed. That is, the cathode metal layer 11 and the anode metal layer 12 are respectively formed at both ends in the longitudinal direction of the substantially solid chip-type solid electrolytic capacitor 10. In the present embodiment, the cathode metal layer 11 and the anode metal layer 12 are composed of conductive metal layers 11a and 12a and coat layers 11b and 12b covering the conductive metal layers 11a and 12a. The conductive metal layers 11a and 12a are both formed of a conductive paste containing silver. The coat layers 11b and 12b are formed of an electroless nickel plating layer and a solder layer.

In addition, two linear electrodes 8 formed of a conductive paste containing silver are formed on the surface of the powder exterior resin 7. As shown in FIG. 3, which is a plan view showing the mounting surface 9 before the cathode metal layer 11 and the anode metal layer 12 are formed, the linear electrode 8 is a capacitor element covered with the powder sheathing resin 7. 1 is formed in the vicinity of both ends in the longitudinal direction. More specifically, each linear electrode 8 is linear and extends to both ends in the width direction along the width direction of the mounting surface 9 (vertical direction in FIG. 3).
As shown in FIG. 3, the mounting surface 9 has a cathode vicinity region 9a (see FIG. 3) connected to a portion exposed from the powder sheathing resin 7 of the cathode lead layer 6 with the two linear electrodes 8 as a boundary. The right region in the middle), the anode vicinity region 9b (left side in the figure) connected to the anode lead-out line 3, and the intermediate region 9c not connected to any of the cathode lead-out layer 6 and the anode lead-out line 3 It is divided into. The intermediate region 9c is located between the cathode vicinity region 9a and the anode vicinity region 9b, and the cathode vicinity region 9a and the anode vicinity region 9b are not adjacent to each other.

As shown in FIG. 1, on the mounting surface 9, the edges of the cathode metal layer 11 and the anode metal layer 12 formed at both ends in the longitudinal direction of the capacitor 10 substantially coincide with the linear electrode 8. That is, as shown in FIG. 5 which is a plan view showing the mounting surface 9 in a state where the cathode metal layer 11 and the anode metal layer 12 are formed, the edges of the cathode metal layer 11 and the anode metal layer 12 are It extends in a straight line along the width direction.
That is, the cathode metal layer 11 is formed in the cathode vicinity region 9 a of the mounting surface 9, and the anode metal layer 12 is formed in the anode vicinity region 9 b of the mounting surface 9.

  The capacitor 10 of the present embodiment has an outer dimension of 2.0 mm × 1.25 mm × 0.65 mm (so-called 2012 size), a rated voltage of 6.3 V, and a rated capacitance of 22 μF.

  Next, a method for manufacturing the capacitor 10 will be described with reference to FIGS. 2 to 5 are plan views showing the mounting surface 9 in the manufacturing process of the capacitor 10.

First, a valve action metal powder made of tantalum is pressure-molded, and an anode lead wire 3 is welded to the anode element 2 obtained after sintering, and then a dielectric oxide film 4 and a solid are formed on the surface of the anode element 2. The capacitor element 1 is formed by sequentially forming the electrolyte layer 5 and the cathode lead layer 6 (capacitor element forming step). Subsequently, the cathode lead layer 6 which is the surface of the capacitor element 1 is covered with the powder exterior resin 7 so that the anode lead-out wire 3 is drawn to the outside (covering step).
Thereafter, as shown in FIG. 2, the powder sheathing resin 7 is partially removed so that a part of the cathode lead layer 6 (right side in the drawing) is exposed. (First removal step). Further, the anode lead-out line 3 is exposed by removing a part of the powder sheathing resin 7 covering the anode lead-out line 3 (second removal step).

Next, the conductive paste is printed on the mounting surface 9 on the surface of the powder exterior resin 7 by a transfer method in two straight lines extending in the width direction of the mounting surface 9, and further dried, as shown in FIG. Thus, the two linear electrodes 8 are formed ( linear electrode forming step).

  Subsequently, the conductive metal layer is obtained by immersing the portion where the powder sheathing resin 7 is removed in the first removal step (right portion in FIG. 3) in a conductive paste containing silver and then drying. 11a is formed. Further, the conductive metal layer 12a is formed by applying a conductive paste containing silver in the vicinity of the portion (left portion in FIG. 3) from which the powdery exterior resin has been removed in the second removal step. . Then, after standing for a predetermined time at room temperature, baking is performed. Then, coat layers 11b and 12b are formed by electroless nickel plating and solder coating (cathode metal layer forming step, anode metal layer forming step).

As described above, in the capacitor 10 according to the present embodiment, the cathode vicinity region 9a that connects the mounting surface 9 to the portion of the cathode lead layer 6 exposed from the powder sheathing resin 7 and the anode vicinity that connects to the anode lead-out line 3. Two linear electrodes 8 are formed that are divided into three regions: a region 9 b and an intermediate region 9 c that is not connected to any of the cathode lead layer 6 and the anode lead-out line 3.
And after forming the said linear electrode 8 on the surface of the powder exterior resin 7, the conductive metal layers 11a and 12a which comprise the cathode metal layer 11 and the anode metal layer 12 are formed with an electrically conductive paste.

Therefore, the linear electrode 8 can prevent the conductive paste having fluidity that becomes the conductive metal layers 11a and 12a from spreading on the surface of the powder-coated resin 7 due to surface tension. Therefore, the dimensional accuracy of the cathode metal layer 11 and the anode metal layer 12 is improved. Therefore, the board mounting performance of the chip-type solid electrolytic capacitor 10 can be improved.
Moreover, since the application level of the cathode metal layer 11 and the anode metal layer 12 can be fixed, the ease of mounting work on the substrate is also improved.

Furthermore, the linear electrode 8 in the capacitor 10 of the present embodiment has a linear shape extending in the width direction of the mounting surface 9.
Therefore, the edges of the cathode metal layer 11 and the anode metal layer 12 can also be linear.

In addition, in the capacitor 10 of the present embodiment, the linear electrode 8 is formed by a transfer method.
Therefore, the linear electrode 8 can be easily formed by an existing method.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various design changes can be made as long as they are described in the claims. Is something. For example, in the above-described embodiment, the case where the linear electrode 8 is formed by the transfer method has been described. However, the present invention is not limited to this, and a spray method, an inkjet method, a dispenser method, or the like can also be used.

Moreover, although the above-mentioned embodiment demonstrated the case where the linear electrode 8 was linear, the linear electrode 8 may be curvilinear.

  In the above-described embodiment, the case where the conductive metal layers 11a and 12a are covered with the coat layers 11b and 12b has been described. However, the present invention is not limited to this. The coat layers 11b and 12b are not formed, and the cathode metal layer 11 and the anode metal layer 12 may be composed of only the conductive metal layer 11a and the conductive metal layer 12a.

  Furthermore, although the case where the anode element 2 made of a valve metal is tantalum has been described in the above embodiment, the present invention is not limited to this. Niobium, aluminum, titanium or the like can also be used as the valve action metal forming the anode element 2.

  In addition, although the case where manganese dioxide is used as the solid electrolyte has been described in the above-described embodiment, a known conductive polymer such as polythiophene, polypyrrole, or polyaniline can also be used.

Moreover, although the above-mentioned embodiment demonstrated the case where the linear electrode 8 was formed with the electrically conductive paste containing silver, it was a wire with the electrically conductive paste which contains at least 1 of zinc, copper, and nickel. The electrode 8 may be formed.

<Comparison test>
Here, as modified examples of the capacitor 10 of the present embodiment, all are substantially the same as the capacitor 10 except that the linear electrode 8 is formed by a spray method (modified example 1). that only in that the electrode 8 is formed by an ink jet method is different (modification 2), and linear electrode 8 is considered only that it is formed by a dispenser method is different a (modification 3). And the capacitor | condenser 10 of a present Example, the capacitor | condenser concerning Modifications 1-3, and the capacitor | condenser (conventional example) same as the capacitor | condenser 10 of a present Example except the point in which the linear electrode 8 is not formed. A comparative test for comparison was performed.

(Comparison test of chip standing failure occurrence rate)
The capacitor | condenser of an Example, the modifications 1-3 and the prior art example was mounted in the mounting substrate, and the test which compares the rate which a chip | tip standing defect generate | occur | produces was done. The mounting on the mounting substrate was performed by a reflow process of heating at 260 ° C. for 10 seconds. Table 1 shows the results of conducting such a comparative test using 300,000 pieces / lot of products for each condition.

(Comparison test of dimensional variation between electrodes)
The test which compares the dimensional variation between the cathode metal layer and anode metal layer of the capacitor | condenser of an Example, the modifications 1-3, and a prior art example was done. The results of this comparative test are shown in Table 2. In addition, the numerical value of Table 2 is an average value of 100 products / lot for each condition.

As shown in Table 1 which is the result of the comparison test of the chip standing failure occurrence rate, the chip standing is generated in the capacitor of the conventional example, but the chip standing is generated in the capacitors of Examples and Modifications 1 to 3. There is no occurrence. That is, in the example and the first to third modifications, the board mounting accuracy is improved as compared with the conventional example.
Moreover, as shown in Table 2 which is the result of the comparison test of the dimensional variation between the electrodes, the dimensional variation of the capacitors of the example and the first to third modifications is smaller than that of the conventional capacitor. The individual difference has decreased significantly.

It is sectional drawing of the capacitor | condenser which concerns on embodiment of this invention. It is a figure which shows the state after the 2nd removal process in the manufacture process of the capacitor | condenser shown in FIG. It is a figure which shows the state after the linear electrode formation process in the manufacture process of the capacitor | condenser shown in FIG. It is a figure which shows the state after forming the conductive metal layer in the manufacture process of the capacitor | condenser shown in FIG. It is a figure which shows the state after the cathode metal layer formation process and anode metal layer formation process in the manufacture process of the capacitor | condenser shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Anode body element 3 Anode lead-out line 4 Dielectric oxide film 5 Solid electrolyte layer 6 Cathode extraction layer 6a Carbon layer 6b Silver layer 7 Powder sheathing resin 8 Linear electrode 9 Mounting surface 9a Cathode vicinity area 9b Anode vicinity area 9c Intermediate region 10 Capacitor 11 Cathode metal layer 12 Anode metal layer 11a, 12a Conductive metal layer 11b, 12b Coat layer

Claims (4)

Capacitor element having an anode element made of a valve metal, an anode lead wire attached to the anode element, and a dielectric oxide film, a solid electrolyte layer, and a cathode lead layer sequentially formed on the surface of the anode element When,
A powder sheathing resin that coats the capacitor element such that a part of the cathode lead-out layer and the anode lead-out line are exposed, and
A cathode metal layer connected to a portion of the cathode lead layer exposed from the powder sheathing resin and formed on the surface of the powder sheathing resin by a fluid material;
A chip-shaped solid, which is connected to a portion of the anode lead-out line exposed from the powder sheathing resin and has an anode metal layer formed on the surface of the powder sheathing resin by a fluid material An electrolytic capacitor,
Two linear electrodes formed of a conductive material on the surface of the powder sheathing resin;
By two the linear electrodes, the portion facing surface of the mounting board of the powder exterior resin, a cathode region near leading to part the cathode lead-out layer is exposed, that is the anode lead-out wire is exposed And a region near the anode not connected to the region near the cathode, and an intermediate region not connected to any of the portion where the cathode lead layer is exposed and the portion where the anode lead-out line is exposed A chip-type solid electrolytic capacitor characterized by being divided into 2. The chip-type solid electrolytic capacitor according to claim 1, wherein the linear electrode is linear. Capacitor element formation step of attaching an anode lead wire to an anode element made of a valve metal and forming a capacitor element by sequentially forming a dielectric oxide film, a solid electrolyte layer, and a cathode lead layer on the surface of the anode element When,
A coating step of coating the capacitor element with a powder sheathing resin;
A first removing step of removing a part of the powder sheathing resin so that a part of the cathode lead layer is exposed;
A second removal step of removing a part of the powder sheathing resin so that a part of the anode lead-out line is exposed;
A cathode metal layer forming step of forming a cathode metal layer connected to a portion exposed in the first removal step of the cathode lead layer with a material having fluidity;
Manufacturing of a chip-type solid electrolytic capacitor comprising an anode metal layer forming step of forming an anode metal layer connected to a portion exposed in the second removal step of the anode lead-out line with a material having fluidity A method,
Before the cathode metal layer forming step and the anode metal layer forming step are performed, the method further includes a linear electrode forming step of forming two linear electrodes with a conductive material on the surface of the powder exterior resin. And
By the linear electrodes of the two formed in the linear electrode forming step, the surface facing the mounting board of the powder exterior resin, a cathode region near leading to part the cathode lead-out layer is exposed, A portion near the anode that is connected to the portion where the anode lead-out line is exposed and is not connected to the region near the cathode, a portion where the cathode lead layer is exposed, and a portion where the anode lead-out line is exposed A method for manufacturing a chip-type solid electrolytic capacitor, characterized in that the chip-type solid electrolytic capacitor is divided into an intermediate region not connected to any of the above. In the linear electrode forming step, a spray method, an inkjet method, a chip form according to claim 3, characterized by forming at least said linear electrodes in any one of the methods of the dispenser method, and transfer method A method for producing a solid electrolytic capacitor.

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