JPH0722272A - Formation of protective film for chip device - Google Patents

Abstract

PURPOSE:To enhance reliability, e.g. solderability, at the time of surface mounting on a printed board by forming a protective film on the outer surface of an element body except the outer electrode thereby avoiding the adverse effect of acid or alkali when a plating film is formed on the surface of the outer electrode. CONSTITUTION:The outer surface of an element is covered with a dielectric tube of glass, for example, except the outer electrode surface and then the tube is fired to form a protective film 3 thus avoiding the adverse effect of acid or alkali when a plating film 5 is formed on the surface of the outer electrode 4. This method enhances the reliability of joint at the time of surface mounting.

Description

[Detailed Description of the Invention] (A paragraph number is attached to each paragraph.)

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a protective film on the outer surface of a chip-shaped component body such as a capacitor except the external electrode surface.

[0002]

2. Description of the Related Art Conventionally, a chip-shaped component (hereinafter referred to as an element) such as a capacitor is laminated and fired so that internal electrode sheets are alternately exposed to a formed laminated ceramic capacitor unfired sheet. Further, a shape has been proposed in which only the external electrode is applied and baked on the end surface where the internal electrode is exposed.

[0003]

In the conventional method of coating the end face of an element with a metal paste or the like and baking it to form an external electrode, the element itself is exposed except for the external electrode surface. When soldering circuit wiring on the board, problems of solder wettability and erosion that occur during soldering, or adverse effects of flux, such as reduction of the element itself due to chlorine component and increase of leakage current, and deterioration of insulation Will cause.

It is known that forming a plating film on the surface of the external electrode is effective for improving the solderability. However, since the conventional element is vulnerable to acid and alkali during the plating process, there is a problem that the plating film cannot be formed on the external electrode as it is.

[0005]

In order to solve the above-mentioned drawbacks, the present invention covers an insulating tube made of glass or the like on the outer surface of the element body except the external electrode surface, and fires the element. By forming a protective film against, it is possible to avoid the adverse effects of acids and alkalis when forming a plating film on the surface of the external electrode, and to ensure the reliability of the connection during mounting and the wettability and erosion of solder that occur during soldering It is possible to improve the insulation property, prevent the reduction of the element itself due to the chlorine component of the flux and increase the leakage current, and increase the insulation property.

[0006]

[Operation] The protective film for the element is formed by covering the outer surface of the element except the external electrode surface with an insulating tube made of glass or the like and baking the element.

(1) It is possible to avoid the adverse effect of acid or alkali when forming a plating film on the surface of the external electrode.

(2) By applying the plating treatment, the reliability of the connection at the time of mounting and the reliability of the wettability and the erodibility of the solder generated at the time of soldering are enhanced, and the adverse effect of the flux, for example, the reduction of the element itself by the chlorine component. It also prevents an increase in leakage current, increases insulation, and improves reliability in surface mounting on a printed circuit board.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1, 2 and 3 are views for explaining the present embodiment.

FIG. 2 shows a layer 1 and an internal electrode 2 such as a capacitor.
Is alternately laminated and integrally fired, and the protective film 3 for the element 6 is obtained by covering the insulating glass tube 7 made of glass in FIG. Is formed.

Next, a metallic paste is applied to both end surfaces where the internal electrodes 2 are exposed and then baked to form external electrodes 4.

Finally, an electrolytic plating process is performed to form a plating layer 5 on the surface of the external electrode 4 to manufacture FIG. 1 of this embodiment.

As described above, the outer surface of the device of the present invention excluding the outer electrode surface is covered with an insulating tube made of glass or the like and baked to form a protective film for the device. It is possible to avoid the adverse effects of acids and alkalis when forming the plated film.

[0014]

As described above, according to the present invention, the outer surface of the device except the external electrode surface is covered with an insulating tube made of glass or the like and baked to form a protective film for the device. It is possible to avoid the adverse effect of acid or alkali when forming a plating film on the surface of the external electrode.

Further, by applying the plating treatment, the reliability of connection at the time of mounting and the reliability of solder wettability and erosion property generated at the time of soldering are enhanced, and reduction of the element itself due to chlorine component in the flux and leakage current. It is possible to prevent the increase and increase the insulating property to improve the reliability of the surface mounting on the printed circuit board, and it is possible to support the surface mounting.

[Brief description of drawings]

FIG. 1 is a diagram according to an embodiment of the present invention.

FIG. 2 is a diagram of an element for explaining an example of the present invention.

FIG. 3 is a view of an insulating tube made of glass or the like for explaining an embodiment of the present invention.

[Explanation of symbols]

 1 Layers of Capacitors 2 Internal Electrodes 3 Protective Film 4 Metal External Electrodes 5 Plating Layers 6 Elements 7 Insulating Tube Made of Glass etc.

Claims (2)

[Claims] 1. A protective film for a chip-shaped component is formed by covering an outer surface of a body of the chip-shaped component such as a capacitor except an external electrode surface with an insulative tube made of glass or the like and firing it. A method for producing a protective film, comprising: (1) The items shall be divided into the items (claims) that describe only the items that are essential to the composition of the invention. (2) Change the line for each claim and add a number of 1 (even if the number of claims is 1, it is described as "[Claim 1]". If it is 2 or more, "[ Claim 1】 "," [Claim 2]] )