KR20010038165A - Conductive paste composition for outer extrod of pile type chip inductor - Google Patents

Abstract

PURPOSE: A conductive paste composition is provided to allow the viscosity and thixotropic index which have an influence to the fluidity to be suitable for dipping process by adjusting the amount of the conductive metallic powder and glass frit, type of organic vehicle and composition ratio. CONSTITUTION: A conductive paste composition is composed of an organic vehicle composed of silver powder 60 to 80 weight%, glass frit 3 to 10 weight%, ethyl cellulose and cellulose acetate propionate 15 to 35 weight%, solvent of 55.0 to 82.0 weight% and additive 3 to 12 weight%. The additive is a caster oil, moist adiabatic dispersing agent and benton. The solvent is formed of a mixture of alcohol, ethylene glycol, mono-propyl ether, diethylene glycol mono-ethyl ether, ethylene glycol 2-ethyl hexyl ether, ester alcohol, and ketone.

Description

Conductive paste composition for outer extrod of pile type chip inductor}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive paste composition for an external electrode of a multilayer chip inductor. In particular, the viscosity and thixotropy index, which affect fluidity by controlling the amount of conductive metal powder and glass frit, the type and composition of organic vehicle, are suitable for dipping. The present invention relates to a conductive paste composition for an external electrode of a laminated chip inductor so as to be within a range.

1 is a perspective view showing the structure of a typical multilayer chip inductor.

In FIG. 1, reference numeral 1 denotes ferrite or ceramic, 2 denotes an internal electrode, and 3 denotes an external electrode.

In general, the conductive paste composition is formed by mixing a conductive metal powder, glass frit and an organic vehicle, and is applied to various components to be electrically connected by screen printing or dipping, and then dried and sintered to form the electrode. It will play the role of.

In a typical multilayer chip inductor, as shown in FIG. 1, internal electrodes are printed and stacked between a ferrite or ceramic sheet by a screen printing method to fabricate a body, and the external electrodes are formed and manufactured by a dipping method.

As the conductive metal powder, gold, silver, palladium (Pd), platinum (Pt) copper, nickel, and the like having excellent electrical conductivity are used, and the glass frit provides bonding strength after firing between the conductive metal powder and the applied part.

The organic vehicle is composed of a binder solid component and a 55.0 to 82.0 wt% solvent, and a cellulose series is generally used as the solid component. The organic vehicle imparts fluidity to the conductive paste composition and at the same time provides a bonding force after drying of the conductive paste composition.

However, when the conventional conductive paste composition is used, problems such as peaks, half-moons, dimples, and pin-holes are not provided because they do not have fluidity and adhesion suitable for dipping. There is a problem that the mechanical and electrical characteristics of the multilayer chip inductor is reduced.

The present invention has been made to solve the above problems of the prior art, the viscosity and thixotropy index affecting the fluidity by adjusting the amount of the conductive metal powder and glass frit and the type and composition of the organic vehicle is suitable for dipping operation It is an object of the present invention to provide a conductive paste composition for an external electrode of a laminated chip inductor which is a value within.

1 is a perspective view illustrating a structure of a general multilayer chip inductor.

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DESCRIPTION OF SYMBOLS 1 Ferrite 2 Internal electrode 3 External electrode

The present invention is characterized in that the organic powder composed of silver powder, glass frit, ethyl cellulose, cellulose acetate propionate, a solvent, and an additive is blended.

Here, the present invention is characterized in that the silver powder is 60 to 80% by weight, the glass frit is 3 to 10% by weight, and the organic vehicle is 15 to 35% by weight.

In addition, the present invention is characterized in that the organic vehicle is 15 to 35% by weight of the ethyl cellulose and cellulose acetate propionate, and 3.0 to 12.0% by weight of the additive is formulated.

In addition, the present invention is characterized in that the additive is castor oil and a dispervict wet dispersant and benton.

In addition, the present invention is characterized in that the solvent is a mixture of one or more of alcohol, ethylene glycol monopropyl ether, diethylene glycol monoethyl ether, ethylene glycol 2-ethyl hexyl ether, ester alcohol, ketone, terpineol.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

The conductive paste composition for an external electrode of the multilayer chip inductor according to the present invention is composed of 60 to 80% by weight of silver powder, 3 to 10% by weight of glass frit and 15 to 35% by weight of the organic vehicle, and has a viscosity of 70 to 100 Kcps. , Thixotropic index of 2 to 3.

The silver powder is a spherical particle having a particle size of 10 μm or less and a plate-shaped powder having a particle size of 30 μm or less are used in a ratio of 4: 6, and the amount within the range of 60 to 80 wt% based on 100 wt% of the total conductive paste composition. But more preferably amounts in the range from 65 to 77% by weight.

On the other hand, when the content of silver powder in the conductive paste composition is less than 60% by weight, the electrical properties of the conductive paste composition are poor, and when it exceeds 80% by weight, poor workability is caused by the increase in viscosity.

Glass frit is provided to provide a bonding force in the sintering of the component to which the dipping method is applied, for example, the laminated chip inductor and the conductive paste composition, wherein the lead-boron-silicate (Pb) having a softening point of 500 to 550 ° C is used. Si-B) glass frit is used.

In the above, the glass frit is less than 3% by weight and the bonding strength between the laminated chip inductor element and the conductive paste composition is lowered. When the glass frit exceeds 10% by weight, the plating frit is caused by an overflow phenomenon of the glass frit.

The organic vehicle is prepared by dissolving a binder solid component in a solvent. The organic binder is composed of 15 to 35% by weight of ethyl cellulose and cellulose acetate propionate, 3.0 to 12.0% by weight of an additive, and 55 to 82.0% by weight of a solvent. .

In the above, the additive of the organic binder is provided for maintaining the dispersibility and adhesion of the conductive paste composition, caster oil, dispervict wet dispersant and benton are used. In addition, the solvent of the organic binder is considered to maintain the proper viscosity of the conductive paste composition and the dissolving power of the binder solid component, alcohol, ethylene glycol monopropyl ether, diethylene glycol monoethyl ether, ethylene glycol 2-ethyl hexyl ether, ester alcohol, One or more of ketone and tipineol are mixed and formed.

On the other hand, the ethyl cellulose and cellulose acetate propionate are included in the amount in the range of 10 to 35% by weight relative to 100% by weight of the total organic binder, preferably in the range of 15 to 27% by weight.

In the above, the content of ethyl cellulose and cellulose acetate propionate in the organic vehicle is less than 12% by weight, poor workability due to the decrease in viscosity of the conductive paste composition, and poor content and binder solid content due to the weakening of the bonding force when drying the conductive paste composition. Insufficiency causes dimples, and if it exceeds 32% by weight, the bonding strength between the chip body and the conductive paste composition is weakened due to a poor workability due to high viscosity and a blister phenomenon due to residual binder components during firing.

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Silver powder 60 75 67 70 72 70 79 Glass frit 7 6 10 3 8 5 6 Organic vehicle A 33 19 B 23 C 27 D 20 E 25 15 F G H Viscosity (kcps) 72 90 75 70 78 77 95 Thixotropic index 2.2 2.7 2.2 2.0 2.2 2.6 2.2 Electrical conductivity 0 0 0 0 0 0 0 Appearance 0 0 0 0 0 0 0 Internal condition 0 0 0 0 0 0 0 Adhesion 0 0 0 0 0 0 0

division Ethyl cellulose Cellulose acetate propionate menstruum Caster oil Dispervic Dispersant Benton A 17 5 67 3 2 3 B 7 22 60 2 2 2 C 8 7 80 One 2 One D 6 14 68 7 2 7 E 12 12 63 2 9 2 F 5 5 80 2 4 2 G 18 22 50 2 3 2 H 12 12 54 3 4 3

Looking at the method of the present invention with reference to Table 1 and Table 2,

First, a silver powder having a particle size of 10 μm or less and a plate shape of 30 μm or less of a 4: 6 silver powder was first mixed with an inorganic binder in the ratio shown in Table 1, followed by an organic binder prepared in the ratio shown in Table 2. Secondary mixing at the ratio shown in Table 1 and then uniformly mixing in a three-roll mill to prepare the conductive paste composition of each example.

Thereafter, each of the conductive paste compositions prepared above was shown in Table 1 by examining the electrical conductivity, appearance, internal state, and adhesion properties by the method described below.

In Table 1, the electrical conductivity is a value obtained by screen-printing the conductive paste composition of each example in the form of a printing pattern for resistance measurement, sintering at 650 ° C. for 10 minutes, and then measuring the resistance, and evaluated according to the following criteria. In other words, if the electrical conductivity is less than 10 ⁻³ Ωcm, it is a good judgment, and if the electrical conductivity is 10 ⁻³ Ωcm or more, a non-compliance determination is made.

In Table 1, the appearance state of the conductive paste composition of each embodiment in the multilayer chip inductor by dipping method, dried at 180 ℃ for 10 minutes, sintered at 650 ℃ for 10 minutes and evaluated by the following criteria. That is, if there are no failure modes such as appearance peak phenomenon, dimple phenomenon, half-moon phenomenon, etc., it is determined to be suitable, and in the opposite case, ineligible determination is made.

In Table 1, the internal state is evaluated according to the following criteria by cross-sectioning the multilayer chip inductor described in the above-described evaluation of the external state and observing the inside thereof. That is, when the multilayer chip inductor body, the internal electrode, and the conductive paste composition are coupled without lift, and there is no pin-hole in the conductive paste composition, a determination is made, and the multilayer chip inductor body, the internal electrode, and the conductive paste are When the composition is lifted up and there is a pin-hole inside the conductive paste composition, an ineligibility determination is made.

In Table 1, the adhesion is obtained by nickel and lead plating the multilayer chip inductor chip described in the above evaluation of the appearance condition, and then pulling a 0.4 mm aluminum wire at both ends of the terminal and pulling it at a constant speed, followed by The binding force of the liver is measured and evaluated according to the following criteria. In other words, if the measured adhesion is more than 1.0 kg, it is determined to be eligible, and if the measured adhesion is less than 1.0 kg, it is determined to be ineligible.

The ratio shown in Table 2 after primary mixing of the inorganic powder with a particle size of 10 μm or less and a particle size of 30 μm or less and a 4: 6 silver powder in the same manner as shown in Table 3 below Secondary mixing with the organic binder prepared in the ratio shown in Table 3 and then uniformly mixed in a 3-roll mill to prepare a conductive paste composition of each comparative example.

Thereafter, each of the conductive paste compositions prepared above was shown in Table 3 by examining the electrical conductivity, appearance state, internal state and adhesion properties by the method as described above.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Silver powder 45 62 70 73 85 72 80 Glass frit 13 20 One 4 5 7 2 Organic Vehicle A 42 B 18 C D E 29 F 23 10 G 21 H 18 Viscosity (kcps) 70 78 72 73 120 77 94 Thixotropic index 1.9 2.5 2.0 2.2 3.5 2.3 3.4 Electrical conductivity × × 0 0 0 0 0 Appearance 0 0 0 × × 0 × Internal condition 0 0 0 0 × 0 × Adhesion × × × 0 0 × ×

As described above, the conductive paste composition for the external electrode of the multilayer chip inductor according to the present invention has a viscosity and thixotropy index suitable for dipping work because the amount of the silver powder and the inorganic binder glass frit and the type and composition ratio of the organic vehicle are controlled to have the laminated chip. It can be used for inductor external electrode.

Claims (5)

A conductive paste composition for an external electrode of a laminated chip inductor, comprising a silver powder, glass frit, ethyl cellulose, cellulose acetate propionate, 55.0 to 82.0 wt% solvent, and an organic vehicle composed of additives. The method of claim 1, The silver powder is 60 to 80% by weight, the glass frit is 3 to 10% by weight, the organic vehicle is a conductive paste composition for an external electrode of a laminated chip inductor, characterized in that 15 to 35% by weight. The method according to claim 1 or 2, The organic vehicle is an electrically conductive paste composition for an external electrode of a multilayer chip inductor, wherein the ethyl cellulose and the cellulose acetate propionate are 15 to 35 wt%, and the additive is 3.0 to 12.0 wt%. The method of claim 3, The additive is a conductive paste composition for an external electrode of a laminated chip inductor, characterized in that the caster oil and the dispervict wet dispersant and benton. The method of claim 3, The solvent is external to the multilayer chip inductor, wherein at least one of alcohol, ethylene glycol monopropyl ether, diethylene glycol monoethyl ether, ethylene glycol 2-ethyl hexyl ether, ester alcohol, ketone and terpineol is mixed. Electroconductive paste composition for electrodes.