JPH0646602B2 - Manufacturing method of chip resistor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a chip resistor.

2. Description of the Related Art Conventionally, a fired plate-shaped alumina substrate 1 having slits for division as shown in FIG. 2 has been prepared as a ceramic base material for chip components such as chip resistors, and the chip pieces on the alumina substrate 1 have been prepared. The first electrode 2 is formed on both ends of the, and the resistor 3 is printed and fired so as to be overlapped with a part of both ends thereof, and then the resistance value is corrected, and the resistor 3 is covered with a glass protective film and fired. After the alumina substrate 1 is divided, the chip electrode is contacted with the first electrode 2 and the second electrodes 5 are formed on both side surfaces of the divided substrate 4 to obtain a chip resistor.

Problems to be Solved by the Invention In the above conventional chip resistor, since the electrodes are formed after the substrate is fired, the shrinkage due to firing causes a large variation in the substrate dimensions, and the substrate is classified according to its classification and its dimensions. A large number of electrode printing masks had to be prepared.

An object of the present invention is to solve the above problems and to manufacture a chip resistor without classifying substrates or preparing a large number of electrode printing masks due to variations in substrate dimensions.

Means for Solving the Problems In order to solve this problem, the present invention provides a rod-shaped unfired green tape base material extruded from a low-temperature firing ceramic base material on both side surfaces, a top surface and a bottom surface connected to them. A step of printing a conductor electrode on a part and drying, a step of forming a slit for division on the green tape base material, a step of simultaneously baking the green tape base material and the electrode, and a part of the baked electrode. A step of printing and firing the resistors so that they overlap with each other, a resistance value adjusting step for aligning the resistance values of the fired resistors, and a step of coating and baking and curing the fired resistors and the resistance correction portion with a polymer resin paint. The protective film forming step, the plating preparing step of dividing the fired base material, and the step of forming a plated film on the fired electrode are sequentially performed.

With this configuration, the present invention can simultaneously fire all electrodes such as both side surfaces, top surface and bottom surface of an extruded rod-shaped unfired green tape base material, and classify the board by the variation of the board size or print the electrode. It is possible to manufacture a chip resistor without preparing a large number of masks for use.

Embodiment An embodiment of the present invention will be described in the order of manufacturing steps shown in FIG.

First, as shown in FIG. 2, low temperature sintering ceramic material (CaO, PbO, B ₂ O ₃ , SiO ₂ yarn), binder (methyl cellulose), lubricant (dynamite glycerin) and water are mixed and dehydrated, After the vacuum kneading step, the green tape substrate 6 is obtained by extrusion through a rectangular nozzle and dried with hot air.

Then, the high temperature baked thick film electrodes Pd-Ag and A are formed on both side surfaces of the green tape substrate 6, a part of the upper surface, and a part of the bottom surface.
g, after forming a coating film by a roll printing method using a paste, dried with hot air, the second electrode 7,8, the first electrode 9,10,
The third electrode 11 is formed.

The electrode-printed green tape base material is 850 ° C. to 95 ° C.
Simultaneous firing is performed in a tunnel furnace in an air atmosphere of 0 ° C. to form a fired substrate with electrodes.

It is connected to a part of the first electrodes 9 and 10 on the firing substrate with electrodes, printed with a thick film resistor (RuO ₂ system) paste, dried and then fired at a high temperature in a tunnel furnace in an air atmosphere. The fired resistor is laser-trimmed to obtain a desired resistance value.

Further, a polymer resin coating material was applied to the resistor correction portion for the purpose of preventing moisture and insulating, and then baked and cured to form a protective film 14.

After that, the electrode part of the divided piece obtained by dividing the chip resistor string along the dividing slit into substrates is nickel-underplated, and then electroplated with either tin or solder or in combination, washed and dried, and the resistance value is checked. Carry out.

A chip resistor is obtained by the above manufacturing process.

As described above, according to the present invention, all the electrodes can be printed at the same time,
In addition, co-firing allows each electrode to be fired once, greatly reducing the number of work steps, and because the ceramic base material and the electrodes are co-firing, the dimensions associated with the thermal contraction of the ceramic substrate seen in the conventional example. Since there is no influence of variation, it is possible to easily print with the same mask without the need to classify the substrates according to dimensions or to prepare a large number of electrode printing masks.

Further, since the green tape substrate of the present invention can be formed into an arbitrary shape according to the nozzle shape by the molding extrusion method, it is possible to round the four corners of both the top and bottom surfaces of the substrate and print the chip resistor. When soldered on the substrate, the solder wraps around a part of the bottom surface, which has the advantage of improving the strength after soldering.

[Brief description of drawings]

FIG. 1 is a process explanatory view showing a method of manufacturing a chip resistor according to an embodiment of the present invention, and FIG. 2 is a process explanatory view showing a method of manufacturing a conventional chip resistor. 6 ... Low temperature firing green tape substrate, 7, 8 ... second electrode, 9, 10 ... first electrode, 11 ... third electrode, 12 ...
... resistor, 13 ... slitting slit, 14 ... protective film.

Claims (1)

[Claims] 1. A step of printing and drying a conductor electrode on both side surfaces of a rod-shaped unfired green tape base material extruded from a ceramic base material for low temperature firing, upper surfaces connected to them, and part of the bottom surface, and Forming a slit for division on the green tape base material, simultaneously firing the green tape base material and an electrode, printing a resistor so as to partially overlap the fired electrode and firing the resistor, A resistance value correction step for aligning the resistance values of the fired resistors, a protective film forming step of coating the fired resistors and the resistance correction portion with a polymer resin coating and baking and curing, and a preparatory step for plating. A method of manufacturing a chip resistor, characterized in that a step of dividing a base material and a step of forming a plating film on the baked electrode are sequentially performed.