JPH06342703A - Manufacture of chip type resistor - Google Patents

Abstract

PURPOSE:To provide a manufacturing method capable of forming a resin protective film wherein the thickness of a protective film is made uniform in the state of a chip, and breaking is made possible along a scribe trench at the time of breaking. CONSTITUTION:The chip type resistor is manufactured as follows; on the surface of a substrate composed of alumina and the like, a resin protective film 6 is formed, in each unit region 2 divided by scribe trenches 3, so as to cover at least each resistor 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a chip resistor, and more particularly to a method for manufacturing a chip resistor having a resin protective film.

[0002]

2. Description of the Related Art A conventional chip-type resistor manufacturing method employs the following procedure as shown in FIG. 3 and FIG. In addition, FIG. 4 shows B- of FIG.
The sectional view along the line B'is shown.

First, a plurality of green sheets made of alumina or the like are laminated, and the laminated green sheets are fired to obtain a substrate 10. Then, vertical and horizontal scribe grooves 12 for braking are formed in a lattice shape by embossing or the like on the surface of the laminated green sheets before firing.

Next, on the surface of the substrate 10, a plurality of unit areas 11 are divided into the unit areas 11 by the scribe grooves 12, and each of the unit areas 11 is made of silver palladium so as to face each other and form a pair. The paste is printed so as to traverse vertical grooves of the scribe grooves 12 on the surface of the substrate 10, and the printed substrate is fired to form electrodes 13. Further, an electrode (not shown) on the back surface is similarly formed by printing at a position on the back surface of the substrate corresponding to the electrode 13 on the front surface of the substrate.

Next, between the electrodes 13 facing each other,
The resistors 14 are electrically insulated from the resistors in the adjacent unit regions in the vertical direction, and the resistors 14 are formed by printing.

Next, a glass protective film 15 is provided so as to cover the resistors 14 provided in each of the unit regions 11 so as to cross the unit regions in a direction substantially orthogonal to the direction in which the electrodes 13 face each other. It is formed by printing in a band shape and firing.

Next, as described in Japanese Patent Publication No. Sho 63-32602 and Japanese Utility Model Publication No. 3-56004, the scribe groove 12 is pressed to brake the substrate 10 for each unit area 11. With the substrate dividing device provided with a pressing roller for forming the substrate 10, the substrate 10 is chipped in the scribe groove 12 to obtain an individual resistance element substrate.

Finally, a chip-type resistor is manufactured by forming side electrodes so that the electrodes 13 on the front surface and the electrodes on the back surface are electrically connected to each chipped resistance element substrate.

[0009]

In recent years, with the progress of electronic technology, highly accurate chip resistors have been required. However, in the above-described conventional method for manufacturing a chip-type resistor, a resistor is formed by printing and baking, the resistance value is adjusted by trimming the resistor, and then the glass protective film is printed and baked. There is a problem that the firing temperature of the film is higher than the firing temperature of the resistor, the resistance value is changed after the resistance value is adjusted to a desired resistance value, and the resistance value is changed.

In recent years, in order to prevent the resistance value of the resistor from changing, a method of manufacturing the protective film with a thermosetting resin has been adopted in the above manufacturing method. When the protective film is a thermosetting resin, the curing temperature of the thermosetting resin can be set lower than the firing temperature of the resistor, so that the resistance value of the resistor does not change. There is a pressing roller in the substrate dividing device, and the pressing force of the roller is applied to the substrate for braking, but the substrate has a crystal structure of ceramic such as alumina,
It can be easily braked, but since the resin that forms the resin protective film has a polymer structure, the resin protective film cannot be braked because the intermolecular bonding force is stronger than that of the substrate. There is.

Further, when the resin protective film is broken together with the substrate, the substrate is cracked, but the resin protective film cannot be braked, so that the resin protective film is peeled off from the substrate, and the resistor portion of the chipped resistor is formed. There is a problem in that moisture or the like will enter and the resistance value will change, or the resistor will be destroyed.

In addition, when the substrate is braked, the force applied by the pressing roller of the substrate dividing device is applied to the scribe groove of the substrate for braking, but since the resin protective film flows into the scribe groove, the pressure is applied. When the pressing force of the roller is applied to the braking groove, the resin protective film intervenes on the braking groove, so the force when scribing the substrate does not concentrate on the scribe groove provided on the substrate, and the There is a problem in that the chip resistor may be broken obliquely, or the chip resistor may be defective due to chipping of the substrate.

Further, since the resin protective film is formed in a band shape so as to extend over a plurality of unit regions, and is then made into a chip,
The amount of resin protective film for each row is almost the same, but since the material of the resin protective film flows into the braking groove,
There is a problem that the thickness of the resin protective film varies among the chips due to the viscosity and surface tension of the resin protective film.

It is an object of the present invention to provide a method for manufacturing a chip type resistor that solves the above problems.

[0015]

In order to solve the above-mentioned object, a method of manufacturing a chip resistor according to the present invention is configured so that vertical and horizontal scribe grooves can be freely braked, and the vertical and horizontal scribe grooves form a unit area. Electrodes that face each other in each of the unit areas are provided on a large number of partitioned substrates.
A step of electrically separating and forming electrodes of unit areas adjacent to each other in a direction substantially orthogonal to the facing direction; and a step of forming a resistor between the electrodes facing each other in each of the unit areas. , A manufacturing method including a step of forming a protective film made of resin so as to cover each resistor independently in each of the unit areas and a step of braking the substrate in each of the unit areas by the scribe groove is adopted. .

[0016]

According to the present invention, in the method of manufacturing the chip-type resistor, when the protective film of the resistor is formed on the substrate, resin is used for the protective film and the unit region is divided by the scribe groove. By forming each resistor independently so as to cover each scribe groove, the protective film does not straddle the scribe groove, so the force when braking the substrate in the scribe groove is the scribe groove provided in the substrate. Therefore, the resin protective film is not applied. Therefore, the following effects are produced.

First, it is necessary to prevent distortion from occurring due to the difference in composition between the substrate and the resin protective film, which deteriorates the adhesion state between the substrate and the resin protective film, and thereby to prevent a gap from being formed between the substrate and the resin protective film. You can As a result, it is possible to prevent the resistance value of the resistor from changing or breaking due to the intrusion of water into the gap between the substrate and the resin protective film, and it is possible to manufacture a chip resistor having high moisture resistance.

Since the substrate can be scribed by the substrate dividing device without any intervening substance on the scribe groove, not only an excessive pressing force is not required but also the substrate can be reliably braked in the scribe groove. It is possible to prevent the substrate from coming off the scribe groove and obliquely cracking, and to prevent the chip resistor from having a defective shape due to the chipping of the substrate. As a result, the number of chip resistors having a defective shape is reduced, and when the chip resistors are manufactured using the same size substrate, the number of chip resistors that can be obtained is increased and the yield is improved.

Further, since the resistors are separately and independently covered,
Not only does the material used for the resin protective film be small, but the resin protective film does not come to the edge of the chipped resistor, preventing the resin protective film from peeling from the edge during manufacturing or mounting. In addition, since the film thickness of the resin protective film is substantially uniform, the heat dissipation characteristics of the resistor are also uniform.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a chip resistor according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a plan view for explaining a part of the steps of the manufacturing method according to the embodiment of the present invention, and FIG. 2 is a view for explaining a part of the steps of the manufacturing method according to the embodiment of the present invention. , A- in FIG.
It is sectional drawing along the A'line.

First, the substrate 1 is obtained by laminating a plurality of green sheets made of alumina or the like and firing the laminated green sheets. The substrate for the braking is provided on the surface of the laminated green sheets before the firing. The vertical and horizontal scribe grooves 3 are formed in a grid pattern by embossing or the like.

Next, the surface of the substrate 1 is divided into a large number of unit areas 2 by the scribe grooves 3, and each unit area 2 is made of, for example, silver palladium so as to face each other and form a pair. A conductive paste is formed by printing so as to cross, for example, a vertical scribe groove among the scribe grooves 3 on the surface of the substrate 1, and the printed substrate is fired to form. At this time, an electrode (not shown) on the back surface is similarly formed by printing and firing at a position on the back surface of the substrate corresponding to the electrode 4 on the front surface of the substrate.

Next, between the opposing electrodes 4 is electrically insulated from the resistors in the unit regions vertically adjacent to each other,
For example, a resistor film paste made of ruthenium oxide or the like is printed and then fired to form the resistor 5. The process up to this point is the same as the conventional method for manufacturing a chip resistor.

Next, the epoxy is separately provided so as to individually cover the resistors 5 provided in each of the unit areas 2 and separately so that the main portion of each of the unit areas 2 does not reach the scribe groove 3. A resin protective film 6 made of a system resin or the like is screen-printed and then dried and cured to form the film.

Next, using a substrate dividing device as described in Japanese Examined Patent Publication No. Sho 63-32602 or Japanese Utility Model Publication No. 3-56004, the substrate 1 is divided by the scribe groove 3 into each unit area 2. To obtain a resistance element substrate that is made into a chip.

Finally, in order to electrically connect the electrode 4 on the front surface and the electrode on the back surface of the resistance element substrate formed into a chip,
For example, an epoxy-based thermosetting resin is mixed with a conductive filler such as fine metal powder to give conductivity, and a conductive polymer is applied in the form of a paste dissolved in a solvent, followed by dry curing. Then, the side electrodes are formed to manufacture the chip resistor.

According to such a manufacturing method, when the substrate 1 is scribed, the resin protective film 6 is formed on the scribe groove 3.
Since there is no intervening force, the pressing force of the roller of the substrate dividing device is concentrated on the scribe groove 3 provided on the substrate 1 at the time of braking, so that not only an excessive pressing force is required but also the substrate 1 is not moved on the scribe groove 3. You can brake reliably. As a result, the number of chip resistors having a defective shape is reduced, and when the chip resistors are manufactured on the same size substrate, the number of chip resistors to be taken increases, that is, the yield is significantly improved.

Further, since the resistors are separately and independently covered with the resin protective film, not only the material used for the resin protective film is small, but also the resin protective film does not come to the end portion of the chip-shaped resistor. Therefore, it is possible to prevent the resin protective film from peeling off from the edge during manufacturing or mounting, and since the film thickness of the resin protective film is almost uniform, the heat dissipation characteristics of the resistor that changed depending on the amount of resin. Will also be uniform.

Although the resin protective film 6 is formed by screen printing, not only the resin protective film is printed but also a dropping method in which a plurality of needle-shaped dropping devices such as syringes are provided for each unit region, A method of transferring with a brush or a roller having hygroscopicity may be used, and a thermosetting resin that is dried and cured is used as the resin, but an ultraviolet curable resin that is cured by irradiation with ultraviolet rays may be used, and further, an electrode, Materials such as resistors are not particularly limited to those described as long as they have similar firing temperatures and characteristics.

[Brief description of drawings]

FIG. 1 is a plan view illustrating a manufacturing method of the present invention.

FIG. 2 is a cross-sectional view taken along the line A-A ′ of FIG.

FIG. 3 is a plan view illustrating a conventional manufacturing method.

4 is a cross-sectional view taken along the line B-B ′ of FIG.

[Explanation of symbols]

 1 ... Substrate 2 ... Unit area 3 ... Scribing groove 4 ... Electrode 5 ... Resistor 6 ... Resin protective film 10 ... Substrate 11 ... Unit area 12 ... Scribe groove 13 ... Electrode 14 ... Resistor 15 ... Glass protective film

Claims (1)

[Claims] 1. A substrate which is freely braked by vertical and horizontal scribe grooves and is divided into a large number of unit areas by the vertical and horizontal scribe grooves, and electrodes which are opposed to each other in each of the unit areas are opposed to each other. An electrode of a unit area adjacent in a direction substantially orthogonal to the direction is formed to be electrically separated from each other, a step of forming a resistor between the electrodes facing each other for each unit area, Manufacture of a chip-type resistor including a step of forming a protective film made of resin so as to independently cover each resistor in each unit area, and a step of braking the substrate in each unit area by the scribe groove. Method.