JP2757949B2 - Chip electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-like electronic component such as a chip resistor and a chip capacitor.

[0002]

2. Description of the Related Art Conventional chip-shaped electronic components such as chip resistors and chip capacitors have side electrode layers provided at both ends of a chip main body as current-carrying terminals of internal electronic elements. Conventionally, as the side electrode layer, a metal-based material obtained by applying and firing a conductive paste containing a metal such as silver or palladium has been generally used. Further, on the surface of the side electrode layer, in order to make soldering at the time of mounting more robust,
A plating layer of nickel, solder, or the like was provided.

[0003] In recent years, with the advance of electronic technology, high-precision electronic components have been required, and the chip-type electronic components have also been required to have higher precision. However, for example, in a chip resistor, a resistor layer formed of a metal oxide provided on an insulating substrate such as a ceramic is re-oxidized by a high temperature when the metal-based side electrode layer is provided, There is a problem that the sheet resistance value of the resistor layer changes.

That is, in a conventional chip resistor, as shown in FIG. 2, a pair of surface electrode layers 4a is provided on both ends of an insulating substrate 1, and a resistor is provided so as to extend over the pair of surface electrode layers 4a. A layer 2 is provided. The resistor layer 2 is trimmed to adjust a resistance value to a desired value. After a protective layer 3 is provided so as to cover the resistor layer 2, both ends of the insulating substrate 1 are provided. Since the metal-based side electrode layer 7 is provided by being applied and fired, the resistance value adjusted by the trimming described above is shifted to a desired resistance value by heat (about 800 ° C. or more) during firing in the side electrode layer formation step. Will occur. Therefore,
The resistance of the obtained chip resistor had a slight error from the desired value.

Therefore, in recent years, a resin-based electrode layer formed by heating and curing a mixture of metal particles such as silver in a thermosetting resin such as an epoxy resin has been proposed as a side electrode layer. Such a resin-based electrode material has a temperature of 150 ° C.
Since the hardening can be performed at a relatively low temperature, the problem of the deviation of the resistance value after the trimming is almost eliminated.

[0006]

However, as shown in FIG. 3, when a resin-based side electrode layer 15 in which metal particles are mixed in a resin as described above is to be applied to a chip resistor, it is difficult to use a resin. If the compounding ratio of the metal particles becomes too high, the metal particles reduce the adhesion to the insulating substrate 1 so that a gap is formed between the insulating substrate 1 and the side electrode layer 15, There is a problem of peeling or falling off.

On the other hand, when the mixing ratio of the metal particles in the resin is reduced, the adhesion to the insulating substrate 1 is improved, but the nickel provided on the surface of the side electrode layer 15 to increase the mounting strength by soldering or the like is provided. In addition, there is a problem that the adhesion to the plating layer 6 such as solder is reduced, and the plating layer 6 cannot be formed uniformly, or peeling occurs even if the plating layer 6 is formed (see FIG. 3).

As described above, when the resin-based side electrode layer is used, there is a contradictory factor that the mixing ratio of the metal particles must be large or small, and the mixing adjustment of the resin and the metal particles is extremely difficult. It is difficult, and even if it is blended so that the adhesion between the temporary insulating substrate and the plating layer can be balanced, sufficient adhesion cannot be obtained, and the product obtained in this manner is not necessarily reliable enough. Was.

An object of the present invention is to solve the above problems and to provide a chip-shaped electronic component having a highly reliable resin-based internal electrode layer without peeling, falling off, or the like.

[0010]

Means for Solving the Problems The present inventor has conducted intensive studies in view of the above-mentioned state of the art, and as a result, when the density of the metal particles in the side electrode layer is reduced toward the chip body and increased toward the plating layer. Found that the adhesiveness of the side electrode layer was improved in both the chip body and the plating layer, and that the peeling of the side electrode layer and the peeling of the plating layer could be prevented in a chip-shaped electronic component having a resin-based electrode layer.

That is, the present invention relates to a chip-shaped electronic component having a side electrode layer on the side surface of a chip body, wherein the side electrode layer contains a synthetic resin and metal particles, and the metal particles are formed on the surface layer of the side electrode layer. The present invention relates to a chip-shaped electronic component characterized by being distributed so as to have a low density in a lower layer.

In the present invention, the side electrode layer is made of a conductive resin containing a resin and metal particles. As the resin, for example, an epoxy resin, a phenol resin,
A thermosetting resin such as a polyimide resin, an ultraviolet curable resin, and the like can be widely used. The curing temperature of the thermosetting resin is, for example, 400 ° C. in order to reduce a change in resistance value.
About 200 ° C. or less, and more preferably about 200 ° C. or less.

As the metal particles, one or more types of metal particles can be widely used without any particular limitation. More specifically, for example, silver, nickel, copper, etc. Particles may be mentioned.

In the present invention, the blending ratio of the metal particles in the lowermost layer of the side electrode layer, ie, the bonding layer with the chip body, is preferably less than about 60% by weight, and as the weight approaches 0% by weight, the chip body becomes smaller. And the adhesive force between them is increased. If the mixing ratio of the metal particles is 60% by weight or more, the adhesion is insufficient, which is not preferable.

In the present invention, the mixing ratio of the metal particles in the surface layer of the side electrode layer, that is, the bonding layer with the plating layer is preferably about 60 to 80% by weight. When the ratio is below the above range, the adhesion to the plating layer becomes insufficient. On the other hand, when the ratio is above the range, the resin component is too small to form the layer.

In the present invention, the metal particles in the external electrode layer may be appropriately mixed so as to be distributed within the above-mentioned range of the mixing ratio. If the mixing ratio of the metal particles in the lowermost layer and the mixing ratio of the metal particles in the surface layer belong to the above-mentioned ranges, respectively. The mixing ratio of the metal particles in the layer between them is not particularly limited.

As described above, the method of providing the side electrode layer in the present invention may be, for example, a multilayer structure having two or more layers. It is only necessary to form a resin layer having a low density of metal particles on the lowermost layer, form a resin layer having a high density of metal particles on the surface layer, and provide the side electrode layer.

[0018]

The resin side electrode layer has a high mixing ratio of a resin component having high adhesion to the chip body such as ceramics on the bonding surface side with the chip body, and the plating layer on the bonding surface side with the plating layer. Since the mixing ratio of the metal particles having high adhesion is arranged to be high, the side electrode layer can maintain a good adhesion state to both the chip body and the plating layer.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings using a chip resistor as an example, but the present invention is not limited to this.

FIG. 1 is a sectional view of a chip resistor according to the present invention. In FIG. 1, reference numeral 1 denotes an insulating substrate, 2 denotes a resistor layer, 3 denotes a protective layer, 4a denotes a front electrode layer, 4b denotes a back electrode layer, 5 denotes a side electrode layer, and 6 denotes a plating layer. Show.

In this embodiment, the resistor layer 2, the protective layer 3, the front electrode layer 4a and the back electrode layer 4b can be provided without any particular difference from the method used in a conventional chip resistor. It is provided in such a manner. A pair of surface electrode layers 4 are provided so as to face both ends of the surface of the insulating substrate 1.
a is formed by printing and baking. Here, the insulating substrate 1
The back surface electrode layer 4b is provided on the back surface of the substrate by printing and baking at a position symmetrical to the electrode layer 4. Next, the resistor layer 2 is formed so that both ends partially overlap between the pair of surface electrode layers 4a.
Is formed by printing and baking. Then, after the resistor layer 2 is trimmed and the resistance value is adjusted, a protective layer 3 is provided so as to cover the resistor layer 2, and a chip body is formed.

On both sides of the chip body 3 formed in this way, resin-based side electrode layers 5 are provided. The side electrode layer 5 includes a lower layer 5a and an upper layer 5b.

In this embodiment, first, as the lower layer 5a, a conductive resin prepared by mixing and adjusting about 30% by weight of metal particles is applied to an epoxy-based thermosetting resin paste having a curing temperature of 150 ° C., and heated at 150 ° C. for 10 minutes. And temporarily dried.

On the lower layer 5a, as an upper layer 5b, metal particles 70 are added to an epoxy-based thermosetting resin paste.
Apply a conductive resin mixed and adjusted to about
After heating at 10 ° C. for 10 minutes, it was further heated and cured at 200 ° C. for 30 minutes to provide the side electrode layer 5.

Next, a nickel plating layer 6a and a solder plating layer 6b were sequentially formed on the exposed portion of the surface electrode layer 4a, the surface of the side electrode layer 5, and the surface of the back electrode layer 4b, and a plating layer 6 was provided. Since the metal particles are arranged at a high density on the surface of the side electrode layer 5 serving as the base of the plating layer 6, it is possible to easily form a uniform and good plating layer as in the normal plating performed on the metal layer. it can.

The chip resistor thus obtained is:
It was of high quality without peeling of the side electrode layer and without peeling of the plating layer.

In the case of the chip resistor as in the above-described embodiment, when a resin-only layer is provided further below the lower layer 5a, the adhesion to the chip body can be further increased, and the side electrode layer can be formed. There is no worry about peeling.

In the above embodiment, the lower layer 5a of the side electrode layer 5
Although the same type of resin and metal particles are used for the lower layer 5b and the upper layer 5b, different types of resin and / or metal particles may be used for the lower layer 5a and the upper layer 5b.

In the above embodiment, the chip resistor was described. However, similar results were obtained when the side electrode layer was applied to a chip multilayer ceramic capacitor in the same manner as in the above embodiment.

[0030]

The chip-like electronic component of the present invention has extremely high precision and high reliability without peeling and falling off of the side electrode layer and without peeling of the plating layer provided on the side electrode layer. And is highly practical.

[Brief description of the drawings]

FIG. 1 is a sectional view of a chip resistor showing one embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional chip resistor.

FIG. 3 is a partial cross-sectional view showing a conventional chip resistor having a resin-based side electrode layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Resistor layer 3 Protective layer 5, 15 Resin side electrode layer 6 Plating layer

Claims (2)

(57) [Claims] 1. A chip-shaped electronic component having a side electrode layer on a side surface of a chip main body, wherein the side electrode layer contains a synthetic resin and metal particles, and the metal particles have a high density on a surface layer of the side electrode layer and a metal layer on a lower layer. A chip-shaped electronic component, which is distributed so as to have a low density. 2. A multilayer structure having at least two side electrode layers, wherein the lowermost layer of the multilayer structure contains less than 60% by weight of metal particles, and the surface layer contains 60 to 80% by weight of metal particles.
The chip-shaped electronic component according to claim 1, wherein the electronic component is contained.