JPH0350703A - Manufacture of chip resistor - Google Patents

Abstract

PURPOSE:To obtain highly accurate, reliable chip resistors which are free from deterioration of a resistance to moisture by performing the plating coat formation process of a coating conductor part prior to the stage of a resistance value regulating process. CONSTITUTION:Both surface and through hole end electrodes 3 are formed at peripheral parts and inwall faces 2 of holes in an alumina sheet substrate 1 equipped with a plurality of the holes. Further, coating resistors 4 are formed so as to connect intervals between the electrodes and insulating glass coating parts 5 are formed on the coating resistors 4. After that, plating coat is formed at the surface electrodes and through hole end electrodes and the resistance regulation of the coat resistors is performed by laser trimming. Then, epoxy resin coating 7 is provided so as to cover trimming grooves and the insulating glass coating parts and then, the alumina sheet substrate is cut into each piece of chip resistors 8.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates primarily to a method of manufacturing a chip resistor intended for mounting on a printed circuit board or the like using an automatic mounting machine.

2. Description of the Related Art Conventionally, in the manufacturing method of this type of chip resistor, according to the process sequence shown in FIG. 2, as shown in FIG. A coated conductor 3 is formed on the substrate surface and the inner wall surface 2 of the hole,
A film resistor 4 and a first film insulator 6 are sequentially formed, the resistance value is adjusted by laser trimming, and a second film insulator 7 is formed to cover the trimming groove and the first film insulator 6. After dividing into individual chip resistors 8 shown in FIG. 4 along the substrate dividing slits 6, a plating film is formed as a film conductor portion 9, and then a characteristic test 9 of the chip resistors is performed.
It was a sorting process.

In FIG. 3, reference numeral 2 denotes the inner wall surface of the hole, which becomes the end surface electrode portion on the side surface of the chip resistor.

3 is a film conductor, which mainly functions as an electrode terminal of a chip resistor. Reference numeral 4 denotes a film resistor, which is formed so as to partially overlap the film conductor 3 .

Reference numeral 5 denotes a first film insulator, which is formed to cover the film resistor 4 to improve the moisture resistance of the resistor.

6 is a slit for dividing the substrate. In Figure 4, 7
is the second film insulator, and V is the resistance value adjustment method.
- It serves to protect the film resistor 4 exposed on the first film insulator 6 by the trimming from the plating solution and to improve the moisture resistance of the resistor. 8 is a chip resistor, which is obtained by dividing the sheet-shaped insulating substrate 1 into individual pieces using the slit 6 for dividing the substrate. Reference numeral 9 denotes a coated conductor portion, on which a plated film is formed in a plating process and becomes an electrode terminal portion of the chip resistor.

In the method for manufacturing a chip resistor configured as described above, the second
The film insulator 7 is made of epoxy resin or the like, and the film forming temperature is 200'C or less. This is much lower than the 600° C. forming temperature of insulating glass by 25°C. In this way, by eliminating the heat treatment process that causes a large process change in the resistance value after the resistance value adjustment process shown in FIG. 2, it is possible to improve the precision of the resistance value and achieve a high yield.

Problems to be Solved by the Invention However, in such conventional manufacturing methods, the epoxy resin used as the second film insulator 7 deteriorates due to the plating solution in the plating process, and the second film insulator 7 is coated with insulating glass. The problem was that it was difficult to achieve the same level of moisture resistance as chip resistors using .

The present invention solves these problems, and even if an epoxy resin or an insulation coating agent with poor plating resistance is used for the second film insulator, insulating glass can be used as the second film insulator. The purpose is to ensure the same level of moisture resistance as the chip resistor used.

Means for Solving the Problems In order to achieve this object, the present invention forms a coated conductor on the periphery of the holes and on the inner wall surface of a sheet-like insulating substrate having a plurality of holes, and forms a conductive film on the surface of the insulating substrate. A film resistor is connected between the film conductors, and a first
After forming a coated insulator on the coated conductor and forming a plating film on the coated conductor, the resistance value of the coated resistor is adjusted by laser trimming, and a second coat is formed so as to cover the trimming groove and the first coated insulator. After forming an insulator, the sheet substrate is divided into individual chip resistors.

Effect: With this method, the process of forming the plating film on the coated conductor portion is performed before the resistance value adjustment process, so that the second film insulator is not affected by the plating solution, and therefore the moisture resistance properties etc. No deterioration will occur.

Example An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a manufacturing process diagram showing a method for manufacturing a chip resistor according to an embodiment of the present invention.

Surface electrodes and through-hole end face electrodes are formed on the periphery of the holes and on the inner wall surface of an alumina sheet substrate having a plurality of holes by a through-hole printing method. Further, a film resistor is formed to connect the electrodes, and an insulating glass coat is formed on this film resistor. Thereafter, a plating film is formed on the surface electrode and the through-hole end face electrode, and the resistance value of the film resistor is adjusted by laser trimming. Then, an epoxy resin coat is provided to cover the trimming groove and the insulating glass coat, and the alumina sheet substrate is cut and divided into individual pieces of chip resistors. As a result, the epoxy resin coat is formed after the plating film forming step, so it is not affected by the plating solution in the plating film forming step. Therefore, it is possible to exhibit the same moisture resistance as when insulating glass is used as the second film insulator.

In this example, the second film insulator was coated with an epoxy resin, but a resin coating agent with poor plating resistance, an inorganic coating agent with SiO bonds, and a low-temperature sintered insulation without plating resistance were used. It may also be made of glass or the like.

Effects of the Invention As described above, according to the present invention, after the resistance value adjustment step,
It is possible to eliminate a heat treatment process that causes a large process change in resistance value, and to realize a highly accurate and highly reliable chip resistor without deterioration of moisture resistance due to a plating solution.

[Brief explanation of drawings]

FIG. 1 is a manufacturing process diagram showing a method for manufacturing a chip resistor according to an embodiment of the present invention, FIG. 2 is a manufacturing process diagram showing a conventional method for manufacturing a chip resistor, and FIG. 3 is a manufacturing process diagram showing a method for manufacturing a chip resistor according to an embodiment of the present invention. FIG. 4 is a schematic diagram showing a part of the sheet-like insulating substrate after the body is formed, and FIG. 4 is a schematic diagram showing a chip resistor.

Claims (1)

[Claims] A coated conductor is formed on the periphery and inner wall surface of the holes of a sheet-like insulating substrate having a plurality of holes, and a coated resistor is further formed on the surface of the insulating substrate so as to connect between the coated conductors. After forming a first coated insulator and forming a plating film on the coated conductor, the resistance value of the coated resistor is adjusted by laser trimming, and a first coated insulator is formed so as to cover the trimming groove and the first coated insulator. 1. A method of manufacturing a chip resistor, which comprises forming a film insulator in step 2 and then dividing the sheet substrate into individual pieces of the chip resistor.