JPH1012485A - Method for forming electrode of electronic part and electrode forming mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent conductive particles from reaching the area other than an electrode forming surface by so positioning a mask against an electronic part that a taper surface contacts to the whole periphery of edge of the electrode forming surface, and under the condition, dry-plating toward the electrode forming surface, for forming an electrode. SOLUTION: In order to form an electrode 122 on a main surface 110, a mask 15 is provided, which has a taper surface 14 contacting to the whole periphery of an edge 13 of the main surface 10 while the entire area of the main surface 10 is exposed. The mask 15 is positioned against a dielectric body 9 so that the taper surface 14, with the entire area of the main surface 10 exposed, contacts to the entire edge 13 of the main surface 10. Under the condition, a target 16 is so assigned as to face the main surface 10, and by sputtering, a conductive film 17 is formed on the main surface 10 and on the surface on the target 16 side of the mask 15. Among the conductive film 17, the part formed on the main surface 10 is taken as the electrode 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an electrode of an electronic component and a mask for forming an electrode used when the method is carried out. The present invention relates to a technique for forming the

[0002]

2. Description of the Related Art An electronic component of interest to the present invention is, for example, a high-voltage capacitor using a ceramic dielectric.

FIG. 3 shows such a high-voltage capacitor 1.
Is shown. The high-voltage capacitor 1 includes, for example, a disk-shaped ceramic dielectric 2, and opposing electrodes 5 and 6 are formed on both main surfaces 3 and 4 of the dielectric 2. The electrodes 5 and 6 have
The lead terminals 7 and 8 are connected as necessary.

FIG. 4 shows an enlarged view of the edge portions of the electrodes 5 and 6. The electrodes 5 and 6 described above are often formed by printing a conductive paste. When the electrodes 5 and 6 are thus formed by printing, they are not usually formed so as to reach the respective edges of the main surfaces 3 and 4 as shown by the solid lines in FIG.
This is because, as shown by the imaginary line in FIG. 4, if the electrodes 5 and 6 are formed over the entire area of the main surfaces 3 and 4 so as to reach the respective edges of the main surfaces 3 and 4, dripping of the conductive paste causes dielectric This is because it is likely to occur on the peripheral surface of the body 2.

However, considering that the capacitor 1 is oriented for high voltage, the electrodes 5 and 6 are
It is preferable to form over the entire area of main surfaces 3 and 4 so as to reach the respective edges of. This is because, when the capacitor 1 is used under high pressure, the lines of electric force concentrate on the edge portions of the electrodes 5 and 6, so that the electric field strength at this portion increases, and the ends of the electrodes 5 and 6 in the dielectric 2 become large. Destruction may occur on the line connecting the edge portions.
And 6 are formed so as to reach the edges of main surfaces 3 and 4, air having a relative dielectric constant lower than that of dielectric 2 exists on the line connecting the edge portions of electrodes 5 and 6. As a result, the withstand voltage can be further improved.

[0006]

Therefore, as shown by the imaginary line in FIG. 4, the main surfaces 3 and 4 of the ceramic dielectric 2 are formed.
It is desired to realize a method capable of forming the electrodes 5 and 6 satisfactorily and efficiently over the entire region.

Therefore, after forming a conductive film on the entire surface of the ceramic dielectric 2 by electroless plating, it is conceivable to remove the conductive film formed in regions other than the main surfaces 3 and 4 by polishing. However, according to this method, not only the productivity is reduced due to the polishing step, but also there is a high possibility that the dielectric 2 is mechanically damaged by the polishing. Particularly, when the capacitor 1 is used for a high voltage, such a machine is used. Damage is a fatal defect.

It is also conceivable to selectively form electrodes 5 and 6 on main surfaces 3 and 4 by dry plating such as sputtering using a mask. in this case,
In order to form the electrodes 5 and 6 over the main surfaces 3 and 4, the mask used is to expose the entire surface of each of the main surfaces 3 and 4, while keeping the mask on the other surface of the dielectric 2. Must be in close contact with such other surfaces to prevent the conductive particles from reaching.

However, in order to make the mask adhere to the surfaces other than the main surfaces 3 and 4 of the dielectric 2 as described above, extremely high dimensional accuracy is required for both the dielectric 2 and the mask. Actually, it is extremely difficult to prepare the dielectric 2 and the mask with such high dimensional accuracy,
In many cases, the conductive particles reach surfaces other than the main surfaces 3 and 4 of the dielectric 2, and similarly to the case of the above-described electroless plating,
In order to remove the conductive film in unnecessary portions, polishing must be performed. Therefore, also in this case, because of the polishing step, not only the productivity is lowered, but also there is a high possibility that the dielectric 2 is mechanically damaged by polishing. The problem is encountered that mechanical damage is a fatal defect.

Therefore, an object of the present invention is to provide a method for forming an electrode over the entire area on which an electrode is to be formed while applying dry plating. An object of the present invention is to provide a method for forming an electrode of an electronic component and a mask for forming an electrode used in the method, which can prevent post-treatment such as polishing so that the electrode does not reach the surface.

[0011]

SUMMARY OF THE INVENTION The present invention is directed to a method for forming an electrode on an electrode forming surface on which an electrode of an electronic component is to be formed. It is characterized by having the following configuration.

That is, a mask having a tapered surface that is in contact with the entire periphery of the edge of the electrode forming surface while exposing the entire region of the electrode forming surface is prepared. Next, the mask is positioned with respect to the electronic component such that the tapered surface is brought into contact with the entire periphery of the edge of the electrode forming surface while exposing the entire region of the electrode forming surface. Then, in that state, dry plating is performed toward the electrode forming surface, and the electrode is formed over the entire area of the electrode forming surface.

The present invention is also used for forming an electrode by dry plating over the entire area of an electrode forming surface on which an electrode of an electronic component is to be formed, ie, an electrode forming mask used to carry out the above method. It is also directed to an electrode forming mask. This electrode forming mask is characterized in that a tapered surface is formed which contacts the entire periphery of the edge of the electrode forming surface while exposing the entire area of the electrode forming surface.

[0014]

FIG. 1 is a schematic front view showing a state in which an electrode forming method for an electronic component according to an embodiment of the present invention is performed. This embodiment is directed to a method for forming an electrode of a capacitor.

FIG. 1 shows a ceramic dielectric 9 for a capacitor. The dielectric 9 has a disk shape, and both main surfaces 10 and 11 are electrode forming surfaces on which electrodes are to be formed. FIG. 1 shows a step of forming an electrode 12 on one main surface 10 by sputtering as an example of dry plating.

In order to form the electrode 12 on the main surface 10, a mask 15 having a tapered surface 14 which is in contact with the entire periphery of the edge 13 of the main surface 10 while exposing the entire area of the main surface 10 is prepared. The mask 15 is positioned with respect to the dielectric 9 such that the tapered surface 14 contacts the entire periphery of the edge 13 of the main surface 10 in a state where the entire region of the main surface 10 is exposed.

In the above state, the target 16 is arranged so as to face the main surface 10, and sputtering is performed. At this time, the sputtering may be continuously performed while the plurality of sets of the dielectrics 9 and the masks 15 are transported while maintaining the state of facing the target 16. By performing the above-described sputtering, the main surface 1
A conductive film 17 is formed on the surface of the mask 15 on the side of the target 16. The portion of the conductive film 17 formed on the main surface 10 becomes the electrode 12. The straight path from the target 16 to the main surface 10 is interrupted by the mask 15 at this portion because the mask 15 overlaps at the peripheral portion of the main surface 10. The electrode 12 can advantageously be formed over the entire area of the ten.

As described above, the electrode 1 on the main surface 10
When the formation of 2 is completed, the dielectric 9 is turned over, the dielectric 9 is positioned on the mask 15 with the other main surface 11 facing the target 16, and the same sputtering is performed again. As a result, a capacitor in which the electrode 12 is formed over the entire area of each of the main surfaces 10 and 11 is obtained.

The angle of the tapered surface 14 of the mask 15 and the amount of overlap of the mask 15 are determined in consideration of film forming conditions such as a film forming rate, a target material, a distance between an electrode forming surface and a target, and a transfer speed. It is decided.

FIG. 2 is a schematic front view showing a state in which an electrode forming method for an electronic component according to another embodiment of the present invention is performed. FIG. 2 shows many elements corresponding to the elements shown in FIG. 1, and corresponding elements are denoted by the same reference numerals, and redundant description will be omitted. The embodiment shown in FIG. 2 is also directed to a method for forming a capacitor electrode by sputtering.

As shown in FIG. 2, together with the mask 15,
Another mask 18 is prepared. This mask 18
Has a tapered surface 21 that contacts the entire periphery of the edge 20 of the main surface 11 while exposing the entire area of the main surface 11 in order to form the electrode 19 on the main surface 11.

As in the case of the above-described embodiment, the mask 15 has the tapered surface 14 with the entire main surface 10 exposed.
Is positioned with respect to the dielectric 9 so as to contact the entire periphery of the edge 13 of the main surface 10, while the mask 18 is configured such that the tapered surface 21 exposes the entire surface of the main surface 11 to the tapered surface 21.
It is positioned with respect to the dielectric 9 so as to be in contact with the entire periphery of the edge 20 of the first.

In this state, facing the main surface 10,
While the target 16 is arranged, the target 22 is arranged so as to face the main surface 11, and sputtering is performed. Thus, the conductive film 17 is formed on the main surface 10 and the surface of the mask 15 on the target 16 side, and the main surface 11 and the target 2 on the mask 18 are formed.
A conductive film 23 is formed on the two surfaces. These conductive films 1
7 and 23, the portion formed on the main surface 10 is the electrode 12, and the portion formed on the main surface 11 is the electrode 19.
Becomes

Thus, according to this embodiment,
The electrodes 12 and 19 can be simultaneously formed on the entire main surfaces 10 and 11.

As described above, the present invention has been described in relation to the illustrated embodiment.
Various embodiments are possible.

For example, the shape of an electronic component to which the present invention is applied, the shape or position of an electrode forming surface provided on the electronic component, and the like can be arbitrarily changed as desired.
For example, the shape of the electronic component need not be a disk as in the illustrated embodiment, but may be, for example, a column or a rectangular parallelepiped. Further, the electrode formation surface does not need to be both main surfaces of the electronic component, and may be only one main surface or a surface other than the main surface.

In the above-described embodiment, sputtering is applied as dry plating, but other methods such as vapor deposition and ion plating can also be applied.

The present invention is not limited to capacitors,
For example, the present invention can be applied to a method of forming an electrode for another electronic component such as a varistor.

[0029]

As described above, according to the present invention, an electrode forming mask having a tapered surface that is in contact with the entire periphery of the edge of the electrode forming surface while exposing the entire area of the electrode forming surface is used. Therefore, the edge of the electrode forming surface can be brought into contact with the tapered surface within the range in which the tapered surface extends, so that the dimensional accuracy between the electrode forming surface and the mask does not need to be so high, so that the mask can be formed relatively inexpensively. Obtainable.

Further, since the contact between the tapered surface of the mask and the edge of the electrode forming surface is such that the edge bites into the tapered surface, a reliable contact state can be obtained by these contacts. Therefore, in the dry plating process, the conductive particles can be reliably prevented from reaching parts other than the electrode forming surface, and post-processing such as polishing for removing the conductive particles deposited on unnecessary parts is not required. . For this reason, productivity is improved, and a cause that may cause mechanical damage is removed, so that the reliability of the obtained electronic component can be improved.

For example, when the present invention is applied to the formation of electrodes of a high-voltage capacitor, electrodes can be formed on the entire surface of the electrode formation surface, and no mechanical damage is caused by post-processing. A capacitor can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a state in which a method for forming an electrode of an electronic component according to an embodiment of the present invention is being performed.

FIG. 2 is a front view schematically illustrating a state in which an electrode forming method for an electronic component according to another embodiment of the present invention is being performed.

FIG. 3 shows a high-voltage capacitor 1 of interest to the present invention.
FIG.

FIG. 4 is a cross-sectional view showing a part of the capacitor 1 shown in FIG. 3 in an enlarged manner.

[Explanation of symbols]

 9 Ceramic dielectric 10, 11 Main surface (electrode formation surface) 12, 19 Electrode 13, 20 Edge 14, 21 Tapered surface 15, 18 Mask 16, 22 Target 17, 23 Conductive film

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Mitsuru Nagashima 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Co., Ltd. Inside Murata Manufacturing Co., Ltd. (72) Nobuyoshi Osuga 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Co., Ltd. Murata Manufacturing

Claims (2)

[Claims] 1. A method for forming an electrode on an electrode forming surface on which an electrode of an electronic component is to be formed, wherein a tapered surface that contacts the entire periphery of an edge of the electrode forming surface while exposing the entire area of the electrode forming surface. Prepare a mask having, so that the tapered surface in contact with the entire periphery of the edge of the electrode forming surface in a state where the entire area of the electrode forming surface is exposed,
Positioning the mask with respect to the electronic component, performing dry plating toward the electrode forming surface in that state, and forming electrodes over the entire electrode forming surface, comprising the steps of: Method. 2. An electrode forming mask for use in forming an electrode by dry plating over an entire area of an electrode forming surface on which an electrode of an electronic component is to be formed, wherein the electrode is exposed while exposing the entire area of the electrode forming surface. An electrode forming mask, wherein a tapered surface is formed so as to be in contact with the entire periphery of an edge of a forming surface.