JPH07312302A - Chip-like electronic part - Google Patents

Abstract

PURPOSE:To form a satisfactory electrode layer with a simplified plating process or without plating, by sequentially forming a silver-containing conductive resin layer, a nickel-containing conductive resin layer and a solder-plating layer. CONSTITUTION:Ag-containing conductive resin paste is applied onto both lateral sides of an alumina base plate 1 so as to cover an upper electrode layer 2 and a lower electrode layer 3, and is pre-dried by a tunnel-type drying furnace with hot air circulation. Then, Ni-containing conductive resin paste is applied onto the pre-dried layer of Ag-containing conductive resin paste and is pre-dried. The Ni-containing conductive resin paste is then cured by the tunnel-type drying furnace with hot air circulation. Thus, Ag-containing conductive resin layers 6, 6 and Ni-containing conductive resin layers 7, 7 are formed. Then, solder- plating layers 8, 8 are formed on the Ni-containing conductive resin layers 7, 7 by electroplating. Thus, lateral side electrode layers 9, 9 for connecting the upper electrode layers 2, 2 with the lower electrode layers 3, 3 are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to chip-shaped electronic parts such as resistors, capacitors and oscillators.

[0002]

2. Description of the Related Art This type of chip-shaped electronic component has a side electrode layer formed on its side surface, and is used by connecting the side electrode layer to a printed circuit board or the like by soldering. For example, the chip resistor has a pair of upper surface electrode layers 1 facing the upper surface of the insulating substrate 11, as shown in the sectional view of FIG.
2 and 12 are formed, a pair of lower surface electrode layers 13 and 13 are formed on the lower surface of the insulating substrate 11 so as to face the upper surface electrode layers 12 and 12, and a resistance is formed so as to extend over the upper surface electrode layers 13 and 13. A layer 14 is formed, a protective layer 15 is formed on the resistance layer 14, and side surface electrode layers 16 are formed so as to connect the upper surface electrode layers 12 and 12 and the lower surface electrode layers 13 and 13 to the side surfaces of the insulating substrate 11. , 16 are formed. Then, on the side surface electrode layers 16 and 16, plating layers 17 and 17 including a nickel plating layer 17a and a solder plating layer 17b are formed. Conventionally, the side surface electrode layers 16 and 16 are made of Ag and P by using glass as a binder.
The Ag paste or Ag-Pd paste mixed with metal powder such as d is printed and baked, or the conductive resin paste mixed with the above metal powder is printed and cured using a thermosetting resin such as an epoxy resin as a binder. Is formed.

[0003]

The side surface electrode layers 16 and 16 in the above-mentioned conventional chip-shaped electronic component are formed from a paste of Ag and glass, or Ag and a thermosetting resin. Even if the electrode layers 16 and 16 are soldered to the printed circuit board as they are, satisfactory alloying cannot be obtained and the fusion between the side electrode layers 16 and 16 and the solder is insufficient, resulting in poor connection. The chip-shaped electronic component may fall off from a predetermined position on the printed board. Therefore, the nickel plating layer 17a for the base and the solder plating layer 17b are sequentially formed on the side surface electrode layers 16 and 16 to obtain solderability.

As described above, it is indispensable to interpose the nickel plating layer 17a and the solder plating layer 17b on the side surface electrode layer in the conventional chip-shaped electronic component in order to enable soldering. Required a plating treatment step. In order to carry out the plating process, a large facility is required, and there are many factors that reduce productivity such as complicated process control. In addition, auxiliary equipment such as waste liquid treatment relating to environmental problems is required, resulting in a large increase in manufacturing cost.

An object of the present invention is to provide a technique capable of forming a good electrode layer even if the plating process is simplified or omitted.

[0006]

The present inventor has been made to achieve the above technical problems, and relates to the following chip-shaped electronic parts. A chip-shaped electronic component having an electrode layer on a side surface of a chip base, wherein the electrode layer is formed by sequentially forming a silver-containing conductive resin layer, a nickel-containing conductive resin layer, and a solder plating layer. Electronic components. In a chip-shaped electronic component having an electrode layer on a side surface of a chip substrate, the electrode layer is formed by sequentially forming a silver-containing conductive resin layer, a nickel-containing conductive resin layer, and a solder-containing conductive resin layer. Chip-shaped electronic parts to be.

In the present invention, the content ratio of Ag in the silver-containing conductive resin layer forming a part of the electrode layer is 6
It is about 0 to 90% by weight, preferably about 70 to 85% by weight. If the Ag content is less than 60% by weight, the conductivity when used as an electrode layer will be low, and if it exceeds 90% by weight, the adhesion to the adherend when used as an electrode layer will be low, which is not preferable. . The silver-containing conductive resin layer can be formed by, for example, applying an Ag-containing conductive resin paste obtained by kneading Ag powder with a thermosetting resin and a solvent and thermosetting. At this time, in addition to Ag powder, Ni, A
A conductive powder such as u, Pt, Cu, Al, or Pd may be appropriately added as long as the conductivity of the electrode is not unnecessarily hindered.

In the present invention, the nickel content of the nickel-containing conductive resin layer forming a part of the electrode layer is about 60 to 90% by weight, preferably about 70 to 85% by weight. When the content of Ni is less than 60%, the conductivity of the electrode layer is lowered and the solderability is deteriorated, which is not preferable.
Adhesion to the contained conductive resin layer is low, which is not preferable. The nickel-containing conductive resin layer can be formed, for example, by applying a Ni-containing conductive resin paste obtained by kneading Ni powder with a thermosetting resin and a solvent and thermosetting.
At this time, besides Ni powder, Ag, Au, Pt, Cu, A
Conductive powders such as l and Pd may be appropriately added as long as the solderability is not unnecessarily reduced.

The form of the conductive powder such as Ag powder and Ni powder used when forming the silver-containing conductive resin layer and the nickel-containing conductive resin layer is, for example, spherical, dendritic, flake-shaped, or amorphous. Any of these may be used, and a dendritic form is particularly preferable in terms of enhancing conductivity. The average particle size of the conductive powder is preferably as small as possible in order to increase the density and increase the conductivity, and is about 30 μm or less, more preferably 1 μm or less.
It is about 10 μm.

The thermosetting resin used for forming the silver-containing conductive resin layer or the nickel-containing conductive resin layer is not particularly limited, and widely known ones can be used. More specifically, for example, heat resistant materials such as epoxy resin, acrylic resin, polyimide resin and phenol resin can be mentioned.
One kind or two or more kinds can be effectively used. Among these thermosetting resins, epoxy resins are preferable in terms of curing temperature and heat resistance. The compounding ratio of the thermosetting resin is about 10 to 40%, preferably about 10 to 25% with respect to the total weight of the silver-containing or nickel-containing conductive resin paste excluding the solvent.

Any solvent can be used without particular limitation as long as it is capable of dispersing or dissolving the thermosetting resin and evaporating at the time of heating for forming the conductive resin paste into the electrode layer. Specific examples include various organic solvents such as terpineol, butyl carbitol acetate, and ethylene glycol dimethyl ether. The blending amount of the solvent varies depending on the type of the solvent, the type and blending ratio of the thermosetting resin, the kneading conditions, etc., and is adjusted so that the conductive resin paste after the kneading has a viscosity within a coatable range. Is preferred.

The Ag powder or Ni powder and the thermosetting resin are adjusted in viscosity with a solvent and sufficiently kneaded with a disper, a ball mill, a triple roll or the like to form a conductive resin paste. The conductive resin paste is applied to an object to be coated, heated for a certain period of time to cure the thermosetting resin, and then returned to room temperature to form an electrode layer.

In addition to the conductive powders such as Ag powder and Ni powder, the thermosetting resin and the solvent, various additives such as antioxidants, fillers and pigments for preventing the conductive powders from being oxidized. It may be used in a range that does not reduce the conductivity of the obtained electrode layer and the fusion property with solder. In the present invention, when the solder plating layer is formed on the nickel-containing conductive resin layer, the solder plating layer is formed by various known plating methods such as electroplating, hot dipping, metallikon, and electroless plating. You can

When the solder-containing conductive resin layer is formed on the nickel-containing conductive resin layer in the present invention, the content of the solder in the solder-containing conductive resin layer is 60 to 90% by weight. %, Preferably about 70 to 85% by weight. If the solder content is less than 60% by weight, the conductivity of the electrode layer is low, which is not preferable, while if it exceeds 90% by weight, the adhesion to the lower layer is low, which is not preferable. Similarly to the silver-containing conductive resin layer and the nickel-containing conductive resin layer, the solder-containing conductive resin layer is kneaded with a thermosetting resin, a solvent, etc., and applied as a solder-containing conductive resin paste. It can be formed by coating and heat curing.

[0015]

EXAMPLES The features of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. (Preparation of Ag-containing conductive resin paste) Average particle size 5 μm
Ag powder and epoxy resin of Ag: Epoxy resin = 1
80% by weight of this mixture and 20% by weight of terpineol were sufficiently kneaded with a disper to obtain an Ag-containing conductive resin paste. (Preparation of Ni-containing conductive resin paste) Average particle size 5 μm
Ni powder and epoxy resin Ni: epoxy resin = 1
The mixture was mixed in a weight ratio of 3: 3, and 80% by weight of this mixture and 20% by weight of terpineol were sufficiently kneaded with a disper to obtain a Ni-containing conductive resin paste. (Preparation of conductive resin paste containing solder) Average particle size 5 μm
Solder powder and epoxy resin of Ni: Epoxy resin = 1
80% by weight and 20% by weight of terpineol were sufficiently kneaded with a disper to obtain a solder-containing conductive resin paste. (Formation and Evaluation of Electrode Layer) The electrode layer was evaluated as a side surface electrode layer in the chip resistor. (Embodiment 1) As shown in the perspective view and the sectional view in FIGS. 1 and 2, a pair of Ag-glass based upper electrode layers 2 and 2 opposed to both sides of the upper surface of a rectangular plate-shaped alumina substrate 1 are provided. Formed on the lower surface of the alumina substrate 1, the upper electrode layer 2,
2 and a pair of Ag so as to face each other with the alumina substrate 1 interposed therebetween.
-Glass-based lower surface electrode layers 3 and 3 are formed, a resistance layer 4 is formed so as to extend over the upper surface electrode layers 2 and 2, and the resistance layer is covered and the alumina substrate 1 of the upper surface electrode layers 2 and 2 is formed. The glass protective layer 5 was formed so that the side portions were exposed. And
The Ag-containing conductive resin paste is applied to the upper electrode layer 2
And the lower surface electrode layer 3 so as to partially cover the lower surface electrode layer 3 and were applied to both side surfaces of the alumina substrate 1, and preliminarily dried in a hot air circulation tunnel type drying furnace at a peak temperature of 120 ° C. for 7 minutes. Then, the Ni-containing conductive resin paste is applied onto the layer obtained by pre-drying the Ag-containing conductive resin paste and pre-dried under the same conditions as above, and then in a hot-air circulation tunnel type drying furnace. It was cured at a peak temperature of 200 ° C. for 60 minutes to form Ag-containing conductive resin layers 6 and 6 having a layer thickness of about 10 μm and Ni-containing conductive resin layers 7 and 7 having a layer thickness of about 10 μm. Next, solder plating layers 8 having a layer thickness of about 10 μm were formed on the Ni-containing conductive resin layers 7 by electroplating. In this way, the side surface electrode layers 9, 9 connecting the upper surface electrode layers 2, 2 and the lower surface electrode layers 3, 3 were formed.

Next, the chip resistor thus obtained is
The printed circuit board was mounted by soldering at 200 to 250 ° C. As a result, the chip resistor was extremely excellent in the fusion property between the side surface electrode layers 9 and 9 and the solder. (Example 2) In the same manner as in Example 1, the Ag-containing conductive resin paste was applied to both side surfaces of the alumina substrate 1 of the chip resistor, pre-dried, and the Ni-containing conductive resin paste was further formed thereon. Was applied and pre-dried. Then
The above-mentioned solder-containing conductive resin paste was applied onto the layer obtained by pre-drying the Ag-containing conductive resin paste and the Ni-containing conductive resin paste, and similarly pre-dried. afterwards,
Cured in a hot air circulation type tunnel type drying furnace at a peak temperature of 200 ° C. for 60 minutes to obtain an Ag-containing conductive resin layer 6,
6. The Ni-containing conductive resin layers 7 and 7 and the solder-containing conductive resin layer having a layer thickness of about 10 μm were formed. In this way, a chip resistor was obtained in which the side surface electrode layers for electrically connecting the upper surface electrode layers 2 and 2 and the lower surface electrode layers 3 and 3 composed of the above three layers were formed. When the obtained chip resistor was soldered to a printed circuit board in the same manner as in Example 1, it was found that the chip resistor had extremely good solderability.

Although the case where the present invention is applied to a chip resistor has been described above, the present invention is not limited to this, and is used for soldering a chip type multilayer ceramic capacitor, a solid electrolytic capacitor, an oscillator, or the like. It is widely applied to a chip-shaped electronic component having an electrode layer to be formed.

[0018]

In the present invention, when the silver-containing conductive resin layer, the nickel-containing conductive resin layer and the solder plating layer are sequentially formed into the electrode layer, the silver in the silver-containing conductive resin layer is , Its high conductivity can improve electrical contact, and the nickel-containing conductive resin layer is
By forming so as to cover the silver-containing conductive resin layer,
What effectively prevents the silver in the silver-containing conductive resin layer from being taken into the solder and destabilizing the electrical contact of the silver-containing conductive resin layer when soldering to a printed circuit board or the like. Is. The solder plating layer is provided as a surface layer of the electrode layer to improve solder wettability and facilitate soldering. In the formation process of the electrode layer thus formed, the plating process can be performed only by solder plating, which can improve the productivity and save the space for the manufacturing equipment of the chip-shaped electronic component. .

Further, in the present invention, when the silver-containing conductive resin layer, the nickel-containing conductive resin layer and the solder-containing conductive resin layer are sequentially formed into the electrode layer, the plating treatment step can be completely omitted. The manufacturing process of the chip-shaped electronic component can be facilitated, the productivity can be further improved, the space of the equipment can be further saved, and the manufacturing cost can be reduced. As described above, according to the present invention, it is possible to obtain an electrode layer having good solderability even if the plating process is simplified or omitted.

[Brief description of drawings]

FIG. 1 is a perspective view showing a chip resistor according to an embodiment of the present invention.

2 is a cross-sectional view taken along the line XX of the chip resistor of FIG.

FIG. 3 is a sectional view showing a conventional chip resistor.

[Explanation of symbols]

 1 Alumina substrate 2 Upper surface electrode layer 3 Lower surface electrode layer 4 Resistance layer 5 Protective layer 6 Silver-containing conductive resin layer 7 Nickel-containing conductive resin layer 8 Solder plating layer 9 Side electrode layer

Claims (2)

[Claims] 1. A chip-shaped electronic component having an electrode layer on a side surface of a chip substrate, wherein the electrode layer is formed by sequentially forming a silver-containing conductive resin layer, a nickel-containing conductive resin layer and a solder plating layer. Chip-shaped electronic parts characterized by. 2. A chip-shaped electronic component having an electrode layer on a side surface of a chip substrate, wherein the electrode layer sequentially forms a silver-containing conductive resin layer, a nickel-containing conductive resin layer and a solder-containing conductive resin layer. A chip-shaped electronic component characterized by being formed.