JPH07263273A - Formation method of terminal electrode - Google Patents

Abstract

PURPOSE:To obtain a terminal electrode whose dimensional accuracy is good by a method wherein a thin-film formation treatment is conducted in a state that an electronic component is flush with a holding plate or protrudes a little and a thin-film electrode is formed only on the edge of the electronic component or on the edge and on a part which is extremely close to it. CONSTITUTION:A plate 7 is overlapped with a holding plate 6 having many square holding holes 5. Electronic components are inserted into the individual holding holes 5. The first edge 8a of every electronic component 8 is made to protrude from the plate face of the holding plate 6. Vertical wall parts 7a are formed at peripheral edge parts of the plate 7. This assembly is put into a vacuum apparatus, and a thin- film formation treatment conducted. A thin film is applied both to the first edge 8a of every electronic component 8 and to the plate face on the upper side of the holding plate 6. Thereby, terminal electrodes whose dimensional accuracy is good can be formed. In addition, when the terminal electrodes are formed on opposite-side edges after the terminal electrodes have been formed on edges on one side, the terminal electrodes can be formed also on the opposite-side edges only by turning over the holding plate itself without reinserting the chip-shaped electronic components into the holding holes. As a result, a process is extremely simple.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a terminal electrode, and more particularly to a method suitable for forming a terminal electrode of a chip type electronic component such as a laminated ceramic capacitor or a chip type ceramic thermistor.

[0002]

2. Description of the Related Art Conventionally, in order to form a terminal electrode of a chip-type electronic component, the terminal electrode forming surface of the element is dipped in an electrode paste and dried and baked to form the terminal electrode. FIG. 4 is a cross-sectional view of a monolithic ceramic capacitor in which terminal electrodes are formed by this conventional method, and terminal electrodes (external electrodes) 3 are formed on both end surfaces of a capacitor body 2 having internal electrodes 1.

[0003]

In the prior art, the dimensional accuracy of the terminal electrode is low due to variations in the thickness of paste coating, sagging after paste coating, and the like. That is, the protruding length L of the electrode in FIG. 4 was large. It should be noted that this protruding length L of the electrode is hereinafter referred to as "electrode length".

[0004]

A method of forming a terminal electrode according to claim 1 is a method of forming a thin film terminal electrode on a pair of first and second parallel end faces of an electronic component by a vapor phase method. A plurality of holding holes through which the electronic component is fitted in a direction perpendicular to the end face are provided so as to penetrate in the plate thickness direction, and the plate thickness is equal to or slightly longer than the length of the electronic component in the fitting direction. Using a holding plate that is smaller than the holding plate and a plate that is superposed on the holding plate. First, an electronic component is fitted into the holding hole of the holding plate, and at this time, one plate surface of the holding plate is attached. The plates are superposed on each other, and the second end faces of the respective electronic components are brought into contact with the plates, whereby the first end faces of the respective electronic components are flush with the other plate face of the holding plate or project therefrom. Then, in this state, the other plate surface side is subjected to a thin film forming treatment by a vapor phase method. A terminal electrode is formed on the first end face of the child component, and then the plate is superposed on the other plate face of the holding plate, and the first end face of each electronic component is brought into contact with the plate. The second end surface of each electronic component is made flush with the one plate surface of the holding plate or protrudes more than that, and in this state, the one plate surface side is subjected to a thin film forming treatment by a vapor phase method. Thus, the terminal electrode is formed on the second end face of each electronic component.

The method of forming a terminal electrode according to claim 2 is characterized in that the electronic component is a monolithic ceramic capacitor or a chip-type ceramic thermistor element.

In the present invention, when the thickness of the holding plate is made smaller than the length of the electronic component in the fitting direction, the difference between the two is within 45% of the length of the electronic component in the fitting direction, especially 23%. It is preferably within the range.

The material of the holding plate and the plate is stainless steel,
Copper or the like is preferable.

[0008]

By performing the thin film forming process with the electronic component flush with the holding plate or slightly protruding, the thin film electrode can be formed only on the end face of the electronic component or only on the end face and its immediate vicinity.

[0009]

EXAMPLES Examples will be described below with reference to the drawings. As shown in FIG. 1, a plate 7 is superposed on a holding plate 6 having a large number of rectangular holding holes 5. An electronic component is inserted into each holding hole 5.

FIG. 2 is a sectional view taken along line II-II of FIG. 1 in a state where the electronic component 8 is inserted into the holding hole 5, and in the present embodiment, the first end face 8a of the electronic component 8 is a holding plate. 6 is slightly projected from the plate surface. A standing wall portion 7a is provided on the peripheral portion of the plate 7.

The state shown in FIG. 2 is put in a vacuum apparatus and a thin film forming process is performed. In addition, the thin film is an electronic component 8
Adheres to both the first end surface 8a of the above and the upper plate surface of the holding plate 6.

Next, the holding plate 6 holding the electronic component 8 and the plate 7 are taken out of the vacuum apparatus, and another plate 7 is taken out.
After it is put on the holding plate 6, the holding plate 6 is turned upside down.
Then, the plate 7 coming to the upper side is removed. In this state, the holding plate 6 holding the electronic component 8 and the plate 7 are placed in a vacuum device, and a thin film forming process is performed. In this state, the second end surface 8b slightly projects from the upper surface of the holding plate 6, upside down from FIG.

After the formation of the thin film terminal electrodes on the second end face 8b is completed, the holding plate 6 and the plate 7 are taken out of the vacuum apparatus, and the electronic component 8 is taken out from the holding plate 6.

In this way, once the electronic component 8 is fitted into the holding hole 5, the terminal electrodes can be formed on both end surfaces of the electronic component 8 without removing it from the holding hole 5.

Next, a concrete example of forming the terminal electrode on the monolithic ceramic capacitor by the above method will be described.

The dimensions of the monolithic ceramic capacitor chip before forming the terminal electrodes are 3.15 mm in width and 1.13 mm in thickness.
The length is 4.40 mm. The dimensions of the holding holes 5 of the holding plate 6 are 3.23 mm in width, 1.15 mm in height, and 3.90 in length.
mm.

First, the monolithic ceramic capacitor is housed in the holding hole 5, then placed on the plate 7 and placed in a vacuum device. The holding plate 6 has a thickness of 3.90 mm, and the length dimension thereof is 0.5 mm shorter than that of the monolithic ceramic capacitor. After that, with a vacuum degree of 0.2 [Pa] and a constant input power of DC 1.0 [kW], V or Cr is used for the adhesion layer, Ni or Cu is used for the barrier layer, and Sn or Sn / Pb is used for the surface layer. To form a terminal electrode. Next, another plate 7 was placed on the surface on which the terminal electrodes were formed, the holding plate 6 was turned upside down, and terminal electrodes were formed on the other end surface in the same manner as above. The chip thus produced becomes a chip-type electronic component having good dimensional accuracy as shown in FIG. Reference numeral 4 represents a thin film terminal electrode.

In Table 1, [Sn / Cu / V], [Sn / Ni]
The dimensional accuracy of the / V] structure thin film terminal electrode product is shown in comparison with the conventional electrode product. The chip length in Table 1 is C in FIGS. 3 and 4, and the electrode length is L in FIGS. It can be seen from Table 1 that the dimensional accuracy is improved by this manufacturing method.

[0019]

[Table 1]

[0020]

As described above, according to the present invention, it is possible to form a terminal electrode having high dimensional accuracy. Also, after forming the terminal electrode on one end face, when forming the terminal electrode on the opposite end face, it is only necessary to turn over the holding plate itself without reinserting the chip type electronic component into the holding hole, and the terminal electrode on the opposite end face as well. Can be formed, so the process is extremely simple.

The method of the present invention is very suitable for forming a terminal electrode of a monolithic ceramic capacitor or a chip-type ceramic thermistor.

[Brief description of drawings]

FIG. 1 is a perspective view of a holding plate and a plate used in the method of the present invention.

FIG. 2 is a view showing a state in which an electronic component is inserted into a holding hole.
2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a cross-sectional view of a monolithic ceramic capacitor chip after forming a terminal electrode by the method of the present invention.

FIG. 4 is a cross-sectional view of a monolithic ceramic capacitor chip after forming a terminal electrode by a conventional method.

[Explanation of symbols]

 1 Internal electrode 2 Capacitor body 3, 4 Terminal electrode 5 Holding hole 6 Holding plate 7 Plate

Claims (2)

[Claims] 1. A method for forming a thin film terminal electrode on a pair of first and second parallel end faces of an electronic component by a vapor phase method, wherein the electronic component is inserted in a direction perpendicular to the end face. Holding hole
A plurality of holding plates that penetrate in the plate thickness direction and have a plate thickness that is equal to or slightly smaller than the length of the electronic component in the fitting direction; and a plate that is superposed on the holding plate. First, the electronic component is fitted into the holding hole of the holding plate, at this time, the plate is superposed on one plate surface of the holding plate, and the second end face of each electronic component is brought into contact with the plate. Let
As a result, the first end surface of each electronic component is made flush with the other plate surface of the holding plate or protrudes therefrom, and in this state, the thin film forming process by the vapor phase method is applied to the other plate surface side. A terminal electrode is formed on the first end face of each electronic component, and then the plate is superposed on the other plate face of the holding plate, and the first end face of each electronic component is brought into contact with the plate. By this, the second end surface of each electronic component is made to be flush with the one plate surface of the holding plate or protruding more than that, and in this state, the thin film forming process is performed on the one plate surface side by the vapor phase method. A terminal electrode is formed on the second end face of each electronic component by applying the above method. 2. The method of forming a terminal electrode according to claim 1, wherein the electronic component is a monolithic ceramic capacitor or a chip-type ceramic thermistor element.