JPH0131283B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method of manufacturing a small resistor.

(Prior Art) As is well known, this type of small resistor is made by providing break grooves vertically and horizontally on the surface of a large substrate made of ceramic or the like so that the small resistor can be cut into pieces. For each unit area, a pair of electrodes and a resistor spanning between the two electrodes are sequentially formed into a thick film by printing and baking, and then the break groove is formed into a thick film. It is customary to use this material and cut it into pieces vertically and horizontally.

In this manufacturing process, the resistors formed as described above are required to be individually trimmed to a desired resistance value. This operation is extremely troublesome to perform on each small resistor after cutting a large board into pieces. Therefore, it is necessary to carry out the process on the large substrate before it is shredded. However, since this work needs to be done while measuring the resistance value of each resistor, at least one of the paired electrodes must be separated from the electrode connected to the other resistor. .

On the other hand, this type of electrode is made of a conductive material containing silver as a main component, but the silver contained in this type of conductive material tends to be easily eluted into the solder during soldering. In order to prevent this, the solder is plated with a metal that is relatively difficult to melt and that can be soldered, such as nickel or copper. Furthermore, this type of metal is easily oxidized, and the oxidation makes it difficult to solder, so in order to prevent this, an oxidation-preventing film, such as a tin film, is further plated.

It is conceivable to use the electrolytic plating method for this type of plating, but as mentioned above, at least one of the electrodes connected to the resistor is independent from the other electrodes, so if you want to perform electrolytic plating, if,
The plating electrodes would have to be individually connected to electrodes that are independent of the other electrodes. This becomes an extremely troublesome task considering the number of unit areas within a large substrate.

Conventionally, therefore, electrolytic plating was performed by placing a plurality of resistors obtained by cutting a large substrate into pieces into a rotating pulse and rotating the resistors. However, the electrolytic plating method using such a rotating barrel has the drawback that it tends to cause uneven plating and a uniform plating film cannot be obtained.

(Problems to be Solved by the Invention) An object of the present invention is to easily enable electrolytic plating on the electrode surface before cutting the resistor into individual pieces.

(Means for Solving the Problems) In the present invention, prior to cutting a substrate into pieces, a conductor is formed so as to connect adjacent electrodes among the electrodes in each unit area. This conductor is formed into a thick film by printing and baking a conductor paste. This conductor is connected to an electrode for electrolytic plating, and plated by immersing it in an electrolytic plating solution.

(Function) When electroplating is performed using the conductor, a plating layer is formed not only on the conductor but also on the surface of each electrode connected to the resistor. Since the rotating barrel method is not used, the plating film is uniform. Also, there is no need to individually connect each electrode to an electrode for electrolytic plating. Therefore, plating work becomes extremely easy.

(Example) An example of the present invention will be described with reference to the drawings. 1st
The figure schematically shows a small resistor manufactured by an example of the method of this invention. In the same figure,
1 is a substrate made of ceramic or the like, 2 is a pair of electrodes provided on the surface of the substrate 1, 3 is a resistor provided across both electrodes 2, and 4 is a resistor provided so as to partially overlap the surface of the electrode 2. The provided conductor 5 is a protective layer made of glass or the like that covers a portion of the resistor 3 and the electrode 2.

The small resistor 6 shown in FIG. 1 is manufactured as follows. First, as shown in FIG. 2, a large ceramic substrate 11 is prepared. A large number of vertical scribe grooves 12 and horizontal scribe grooves 13 are provided in parallel on the surface. The area defined by the vertical and horizontal scribe grooves is defined as a unit area 14.
This unit area corresponds to one small resistor.

A pair of electrodes 2 facing each other are formed on both left and right sides of each unit region 14 as shown in FIG. this is
It is formed by printing and firing a conductive paste mainly composed of Ag, such as an Ag-Pd paste. In principle, each electrode 2 is formed independently from each other, but as shown in the example shown in the figure, vertical scribe grooves 12
The electrodes located on both sides of the electrode may be integrally connected to each other. This is because there is no problem in individually measuring the resistance values of the resistors formed in the next step.

Next, a resistor 3 is formed across each pair of electrodes 2 in each unit region 14 . This is formed by printing and firing a resistor base, for example RuO ₃ paste. Thereafter, while measuring the resistance value of the resistor 3 using a pair of electrodes, trimming, for example, laser trimming, is performed to obtain a desired value (see FIG. 4). In the figure, 15 indicates a trimming trace. This trimming is performed because both electrodes in each unit area 14 are electrically separated from electrodes in other unit areas.
This can be easily carried out because the resistance value of each resistor is measured without any interference from other resistors.

Next, among the electrodes 2 in each unit area 14, the electrodes 2 arranged in a direction perpendicular to the directions facing each other, that is, in the illustrated example, in a vertical direction, are collectively connected. This connection is made by the conductor 4. That is, the conductor 4 is provided to overlap the surfaces of the electrodes 2 arranged in the vertical direction. Specifically, it is formed by printing and baking a conductive paste (see FIG. 5). In this case, each conductor 4 needs to be electrically separated from other conductors 4 arranged in the vertical direction, but for electrodes 2 that are electrically integrated with each other in unit areas arranged in the horizontal direction, the same conductor 4 is required.
You may also connect with

After forming the conductors 4 in this manner, each conductor 4 is connected to an electrode for electrolytic plating, and is immersed in an electrolytic plating solution to form a solderable layer and an anti-oxidation layer. In this case, each large substrate may be electrolytically plated, but it is separated into strip-shaped substrates by scribing along the vertical scribe grooves 12, and the conductor 4 of each strip-shaped substrate is connected to an electrode for electrolytic plating. Alternatively, electrolytic plating may be applied. After that, it is shredded using the scribe groove 13.

Note that when it is necessary to provide the protective layer 5, a conductor paste for the conductor 4 is printed before the plating process, and then glass is printed to cover the resistor 3, and this and the conductor 4 are fired at the same time. It is better to do this. This is because if the two were fired separately, the resistance value might drift since the resistor 3 has already been trimmed.

After electrolytic plating, the resistor is subdivided using each scribe groove to obtain a small resistor as shown in FIG. Note that the small resistor shown in FIG. 1 does not have electrodes extending to the end surface and back surface of the substrate 1. A resistor having such a shape is suitable as a small resistor installed on a conductive support plate. In this case, connection with other circuit elements etc. is possible by wire bonding or soldering to the conductor 4 or electrode 2.

(Effects of the Invention) As detailed above, according to the present invention, the electrolytic plating process on the electrode surface can be performed before the substrate is shredded. It has the advantage of being easy to implement.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a small resistor manufactured by the method of this invention, and FIGS. 2 to 5 are plan views showing the manufacturing process of this invention. 11...Large substrate, 2...Electrode, 3...Resistor, 4...Conductor, 12, 13...Scribe groove,
14...Unit area.

Claims (1)

[Claims] 1. A large substrate which can be cut into pieces by vertical and horizontal scribe grooves and which is divided into a large number of unit areas by the vertical and horizontal scribe grooves, has a pair of electrodes facing each other in each unit area. , a step of forming electrodes electrically separated from each other from electrodes of other unit regions arranged in a direction perpendicular to the facing direction, a step of forming a resistor between a pair of electrodes for each unit region, a step of forming a resistor between electrodes of a pair in each unit region, a step of forming a conductor to electrically connect electrodes formed separately; a step of connecting the conductor to an electrode for electrolytic plating and electrolytically plating the surfaces of the electrode and the conductor; and using the scribe groove. A method of manufacturing a small resistor, which comprises the step of cutting the substrate into small pieces.