JPH0383311A - Method for forming electrode of electronic part - Google Patents

Abstract

PURPOSE:To form an electrode having an ideal gap length on an electrode forming surface under the state of no electrode drooping by providing a bonding agent between the electrode forming surface of the raw substance of an electronic part and a transferred electrode on said surface, and heating the device. CONSTITUTION:A paste-shaped electrode 2 is applied on one surface of a film 4. Then the electrode 2 is dried. A bonding agent 3 is applied so as to cover the dried electrode 2 and dried. A preheated dielectric plate 1 is compression- bonded to a film 4 which is formed of the bonding agnet 3 and the electrode 2 in the laminated state. Thereafter, the dielectric plate 1 in the compression- bonding state is released from the film 4. Then, the electrode 2 is transferred on another electrode forming surface 1a of the dielectric plate 1 by the same way. Thus the electrodes 2 are formed on the electrode forming surfaces 1a on both sides of the dielectric plate 1. Then the dielectric plate 1 is heated. The bonding agent 3 between the electrode 2 and the dielectric plate 1 is contracted in said heating. Thus the electrodes 2 are also contracted. The electrodes are formed on the electrode forming surfaces of the raw substance of the electronic part except for the entire peripheral part.

Description

[Detailed Description of the Invention] The present invention is suitable for forming electrodes on the electrode forming surface of an electronic component body excluding the entire periphery in electronic components such as single plate capacitors. The present invention relates to a suitable method for forming electrodes of electronic components.

A single-plate capacitor, for example, as shown in FIG.
, with a gap length G relative to the diameter of the dielectric plate 1,
In other words, it has a structure in which an external terminal (not shown) is attached to the electrode 2 formed on the entire periphery, and resin is molded on the outside of the dielectric plate 1.

The reason why the electrode 2 is formed with a gap length G relative to the diameter of the dielectric plate 1 as described above is understood from the relationship between the gap length G and the breakdown voltage of the capacitor shown in FIG. This is because there is a view that the breakdown voltage is not maximized when the gap length is G=O, but is maximized when a minute gap G0 is provided.

The reason for this is that when the gap length is G = 0, if there is a defect such as a chip or a crank at the end of the dielectric plate, the variation in breakdown voltage becomes extremely large, and the breakdown voltage is expressed by taking the average value. This is thought to be due to a drop in voltage.

By the way, regarding the gap length G0 that maximizes the breakdown voltage, for example, in the case of a general dielectric plate made of BaTiOs material and having dimensions of 4 mm in thickness and 18 mm in diameter, 0<G, It has been confirmed through experiments that the range is ≦0°1511II11.

However, even if you try to adjust the gear length within this range, screen printing is generally used to form capacitor electrodes, so the electrodes may be misaligned due to printing accuracy or variations in the dimensions of the dielectric plate. likely to occur,
As a result, there is a possibility that the gap length cannot be kept within the above-mentioned range, or that the electrodes may be formed in a sagging state on the side surface of the dielectric plate. Further, if the electrode is formed in such a state, there is a problem that withstand voltage performance and long-term reliability are likely to deteriorate.

The present invention makes it possible to form electrodes with the gap length within the optimum range as described above, and thereby makes it possible to obtain electronic components such as capacitors with high withstand voltage and high reliability. The present invention aims to provide a method for forming an electrode.

The present invention provides an electrode forming method for an electronic component in which electrodes are formed on the electrode forming surface of an electronic component body excluding the entire periphery. A step of transferring an electrode by a thermal transfer method with an adhesive interposed, and heating the electronic component body onto which the electrode has been transferred to cause the adhesive to shrink and disappear as the adhesive heat shrinks. The method is characterized by a step of shrinking and baking the electrode.

In the present invention, an adhesive is interposed between the electrode forming surface of the electronic component body such as the dielectric plate mentioned above and the electrode transferred to this surface. The adhesive is heated to thermally shrink, and the electrodes on it also shrink accordingly. At this time,
By setting conditions so that the adhesive disappears,
Electrodes are formed on the electrode formation surface of the electronic component body except for the entire peripheral edge.

The method for forming electrodes of an electronic component according to the present invention will be explained with reference to FIGS. 1 and 2, taking as an example the case where it is applied to the single-plate capacitor shown in FIG. FIG. 1 is a flowchart showing the electrode forming method according to the present invention, and FIG. 2 is a diagram showing the state of each step. In addition, (a) in Figure 2,
(b), etc. correspond to each step with (a), (b), etc. on the right side in FIG.

First, as shown in FIG. 2(a), for example, the thickness is 30 mm.
A thermal transfer film 4 having a heat resistance of m is prepared.

Next, as shown in FIG. 2(b), a paste-like electrode 2 is applied to one side of the prepared film 4 by, for example, screen printing or doctor blade printing, and then
Dry in an atmosphere at a temperature of about °C. The size of the electrode 2 is determined so that it is wider than the electrode forming surface of the dielectric plate l shown in FIG. 3, that is, one side 1a.

Then, as shown in FIG. 2(c), an adhesive 3 is applied to cover the dried electrode 2 and then dried. As the adhesive 3, a thermoplastic resin such as polyvinyl butyral, polyamide, ethylene vinyl acetate copolymer, or acrylic polyolefin is dissolved in a suitable solvent such as toluene, xylene, methyl ethyl ketone, or isopropyl alcohol. This application is performed, for example, by a doctor blade method, a spray atomization method, or the like.

As shown in FIG. 2(d), for example, one
A dielectric plate 1 preheated to about 30'C is crimped. For this pressure bonding, any method such as a press method or a roller method can be used. Note that the pressure bonding force and the preheating temperature of the dielectric plate 1 are determined as appropriate depending on the type and thickness of the adhesive 3 used.

Thereafter, the crimped dielectric plate 1 is peeled off from the film 4. As a result, as shown in FIG. 2(e), the dielectric plate 1
The electrode 2 is transferred to one electrode formation surface 1a on the entire surface with the adhesive 3 in between, that is, in a state where the gap length G=O.

Thereafter, the electrodes 2 are transferred to the other electrode forming surface 1a of the dielectric plate 1 in the same manner, and the electrodes 2 are formed on both electrode forming surfaces 1a as shown in FIG. 2(f). The dielectric plate 1 is heated, for example, at a temperature of about 820° C., which is sufficient to bake the electrodes.

During this heating, the adhesive 3 present between the electrode 2 and the dielectric plate 1 contracts, and thereby the electrode 2 also contracts. Since the heating temperature is higher than the temperature at which the adhesive 3 disappears, when the adhesive 3 disappears, the contracted electrode 2 is transferred to the dielectric plate 1.
It is in a state where it is directly attached to. As a result, Figure 2 (g)
As shown in , the electrode forming surface 1a of the dielectric plate 1 has a radius slightly smaller than that radius over the entire circumference, that is, the gap length G is in the optimum range of 0.05 to 0.15 am. Electrode 2 is formed.

In this way, in the present invention, since the electrode 2 is contracted according to the amount of contraction of the adhesive 3, the gap length G can be adjusted by adjusting the type, thickness, concentration, etc. of the adhesive 3. It is possible to match the optimum value regardless of the size of the electrode forming surface.

Further, since contraction occurs in all directions, the electrode formation surface does not need to be circular, and electrodes can be formed in any shape without any problem.

Note that if the dielectric plate 1 changes in size during the heating and cooling process during electrode baking, the amount of shrinkage of the electrode 2 will change due to the relative dimensional change with this dielectric plate 1. Therefore, it is preferable to use a fired product with relatively little dimensional change.

However, if the relative dimensional change is taken into consideration, it is also possible to use the material before firing.

Furthermore, although the present invention is applied to a single-plate capacitor in the above embodiment, the present invention is not limited to this, and can be applied to general electronic components in which electrodes need to be formed except for the entire periphery of the electrode forming surface.

Light and History As detailed above, in the case of the present invention, an electronic component body in which an adhesive is interposed between the electrode forming surface and the electrode transferred to this surface is heated. Since the adhesive is thermally shrunk and the electrode on it is also shrunk accordingly, it is possible to form an electrode with an ideal gap length of 4° on the electrode forming surface without any deformation of the electrode. Moreover, in view of the principle of electrode formation, it is possible to correspond to any shape of the electronic component element body.

Furthermore, electronic components such as capacitors obtained in this manner have a high withstand voltage and are free from electrode sagging, so high reliability can be ensured.

[Brief Description of the Drawings] Figure 1 is a flowchart showing the method of the present invention, and Figure 2 is a flowchart showing the method of the present invention.
3 is a perspective view showing the state of an electrode formed according to the present invention, and FIG. 4 is a graph showing the relationship between gap length and breakdown voltage. DESCRIPTION OF SYMBOLS 1... Dielectric plate, 1a... Electrode formation surface, 2... Electrode, 3... Adhesive, 4... Film.

Claims (1)

[Claims] (1) In an electrode formation method for electronic components in which electrodes are formed on the electrode formation surface of an electronic component body except for the entire periphery, an adhesive is interposed between the entire electrode formation surface of the electronic component body. A process of transferring the electrode by a thermal transfer method, heating the electronic component body onto which the electrode has been transferred to cause the adhesive to heat shrink and disappear, and shrink the electrode along with the heat shrink of the adhesive and sinter it. 1. A method for forming electrodes of electronic components, comprising the steps of: