JP2822123B2 - Ni-containing nonmagnetic conductive paste and electronic component having the conductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Ni-containing non-magnetic conductive paste and an electronic component having the conductor, and more particularly to a conductive paste capable of obtaining various conductors utilizing the special properties of a Ni-containing non-magnetic alloy, and a method for producing such conductive paste. Electronic components used.

[0002]

2. Description of the Related Art Conductors such as electronic components such as multilayer ceramic capacitors, resistors, and multilayer wiring boards are made of Ag, Ag.
─ It is formed by applying a conductive paste containing a metal such as Pd, Ni, Cu or the like by printing or the like. For example, in a multilayer ceramic capacitor, a plurality of sets of internal electrode patterns are formed by printing a conductive paste containing Ni powder on dielectric ceramic green sheets, and these are further laminated so that the internal electrode patterns of each set face each other. Then, after crimping, each set is cut. The individual body obtained by the cutting is fired in a non-oxidizing atmosphere, and terminal electrodes connected to each internal electrode are formed on the end face of the fired body by applying and baking an Ag paste.

[0003] A multilayer ceramic capacitor component or the like is actually used by being soldered to a printed circuit board. At this time, a terminal electrode made of Ag is dissolved in molten solder and melted out, which is a so-called “solder corrosion”. The phenomenon of "we" may occur, and a connection failure with the internal electrode may occur. In order to prevent this, a Ni layer that is hardly melted in solder is provided on the Ag terminal electrode by electrolytic plating, and solder electrolytic plating with good wettability to solder is continuously performed thereon. .

In order to perform such electrolytic plating of Ni and electrolytic plating of solder, a so-called rotary barrel method is used. That is, an anode is provided in a plating solution tank, and a cathode is provided in a rotatable barrel. A chip component to be plated is placed in the barrel, and plating is performed while rotating. On this occasion,
In the barrel, so-called dummy, which is an iron spherical body or a columnar body having almost the same dimensions as these chip parts, is mixed in approximately the same number as the chip parts, and the connection efficiency between the cathode of the barrel and the chip parts is increased. It is improved by the intervention of a dummy. The Ni electroplating and the solder electroplating are performed by changing the plating bath, but the dummy and the chip component must be separated after the completion of the solder electroplating. To perform this separation, the dummy and chip parts are washed together in a barrel and then taken out together.
After being dried, it is put on a separator.

The dummy sorter accommodates the dummy and chip components and sequentially supplies them in a fixed number, a work supply section which is continuous with the work supply section, and which is circulated in the horizontal direction, and is provided in the middle of the transfer belt. The dummy and chip components supplied from the work supply unit are subjected to the action of the magnetic drum while being conveyed by the conveyor belt, whereby the iron dummy is attracted to the magnetic drum. It is carried away, and only the chip component is left and transported as it is, and collected at a predetermined location.

[0006]

However, in such a sorting method using a dummy sorter, since the terminal electrodes of the chip components have a magnetic Ni plating layer, some of them are attracted to a magnetic drum. It is carried along with the dummy and scraped off the magnetic drum. Then, the dummy in which these chip components are mixed is again subjected to the dummy sorting machine, and the same operation as above is repeated. In such a sorting method, the accuracy of the sorting is low, the yield is low, and there is a problem in productivity due to the necessity of repeatedly performing the sorting operation.

An object of the present invention is to prevent the phenomenon of “solder erosion” by coating an electrode made of Ag or the like.
Another object of the present invention is to provide a conductive paste for forming a conductive film having good separability from an iron dummy and an electronic component including the conductive material.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a Ni-containing non-magnetic conductive paste containing a non-magnetic alloy composed of Ni, Co, and Fe.

The present invention also relates to the above-mentioned Ni-containing non-magnetic conductive material.
N having a conductor obtained by baking a paste coating film
An electronic component having an i-containing nonmagnetic conductor is provided.

In the present invention, the nonmagnetic alloy consisting of Ni, Co, and Fe refers to 28 to 29% of Ni and 17 to 17% of Co.
It is composed of 18% and the balance of Fe, and the trade names are Kovar and Fernico. These are described in the Dictionary of Physical and Chemical Sciences (page 745). The fact that Kovar is conductive and non-magnetic is described in the Handbook of Metals (5th edition (1990 edition), p. 645).

[0011] These alloy powders are mixed with a resin component such as a vinyl resin, a dispersant such as a higher fatty acid, a solvent and, if necessary, a ceramic powder such as barium titanate to produce a conductive paste. Further, for example, in the case of forming a terminal electrode after firing a ceramic capacitor chip body, a conductive paste obtained by further adding glass to the above composition can be used.

The electronic component with a Ni-containing non-magnetic conductor according to the present invention is an electronic component with a conductor of the above-mentioned conductive paste. The types of the electronic component include ceramic components such as multilayer ceramic capacitors and the like. Small products such as resistors can be used, and magnetic separation after barrel plating for these products can be applied in exactly the same manner.

Further, the above-mentioned Ni-containing non-magnetic conductor used in the present invention does not cause the “solder erosion” phenomenon.
It is also effective to use it as a conductor of a multilayer wiring board, and since it has a similar thermal expansion coefficient to that of a semiconductor silicon substrate or hard glass, it can also be used as a conductor used in these.

[0014]

The non-magnetic alloy made of Ni, Co, and Fe does not dissolve in solder, is non-magnetic, and has a thermal expansion coefficient close to that of glass and silicon. Therefore, it is suitable as a conductor for various electronic parts requiring these properties. . For example, it is not possible to cause the phenomenon of "solder erosion" because it does not easily melt in molten solder.
Since it has properties similar to the i-plated film and is a non-magnetic material thereon, it can be easily separated from an iron dummy by a magnetic action.

[0015]

Next, embodiments of the present invention will be described. Example 1 Dielectric ceramic material powder containing barium titanate as a main component, dispersant (oleic acid, etc.), plasticizer (DOP)
Etc.), a resin (polyvinyl butyral, etc.), an organic binder containing a solvent, etc. are kneaded to prepare a slurry.
ET film (polyethylene terephthalate film)
Apply and dry on top. And it peeled off from a PET film and produced the ceramic green sheet of 100 mm square which has a thickness of about 40 micrometers. On this ceramic pattern sheet, several thousand internal electrode patterns for a multilayer ceramic capacitor are printed using a Ni conductive paste containing Ni as a main component, 20 sheets of this sheet are stacked, and further, the internal electrodes are printed on the upper and lower sides. Nine sheets, each of which has not been made, are stacked and crimped. This is 1.92mm long and 0.96m wide
By cutting into a size of m, a multilayer ceramic capacitor body chip was prepared.

Separately, 29Ni @ 18Co-53Fe (number is%) alloy powder having an average particle size of 2 μm 90 g ethyl cellulose 16 g dielectric ceramic material powder containing barium titanate as a main component 10 g butyl carbitol 94 g monooleic acid ( (Dispersant) 0.5 g Dioctyl phthalate (DOP) 1.0 g was mixed and stirred, and then kneaded with a three-roll kneader to prepare a conductive paste.

After the conductive paste is applied to the end face of the multilayer ceramic capacitor element chip, hydrogen gas is applied for 2 hours.
% In a nitrogen gas atmosphere containing 1%. The dimensions of the obtained chip were 1.64 mm in length, 0.8 mm in width, and 0.83 mm in thickness.

Next, about 120,000 of the above chips and approximately the same number of 1.5 mm-diameter iron spherical dummies were placed in the barrel of a barrel plating tank, and solder electrolytic plating was performed.
A plated film having a thickness of 2 mm was formed to obtain a multilayer ceramic capacitor chip. After washing with water, the multilayer ceramic capacitor chip and the dummy were taken out of the barrel, dried, and then subjected to a separation operation once by a dummy separator described in the section of “Prior Art”. As a result, no mixing of the multilayer ceramic capacitor chip was found in the dummy scraped off the magnetic drum.

Example 2 In Example 1, 28Ni @ 17Co-55Fe (numerical%) alloy powder was used instead of 29Ni @ 18Co-53Fe alloy powder in the above-described composition of the conductive paste used therein, and barium titanate was used. Borosilicate glass frit is used without using a dielectric ceramic material powder whose main component is 1.
A conductive paste to which 0 g was added was prepared, and the prepared conductive paste was applied to a corresponding portion on a multilayer ceramic capacitor chip body baked under the above conditions without applying anything, and baked at 1150 ° C. Similarly, a multilayer ceramic capacitor chip was prepared. These chips were also separated from the dummy in the same manner as in Example 1. However, no mixing of the multilayer ceramic capacitor chip was found in the dummy scraped off from the magnetic drum.

COMPARATIVE EXAMPLE In Example 2, a commercially available Ag conductive paste was used in place of the conductive paste used therein, and the Ag conductive paste was baked at 800 ° C., and Ni electrolytic plating was performed thereon. Thereafter, a multilayer ceramic capacitor chip was prepared in the same manner except that the solder electrolytic plating was performed, and these were also separated from the dummy in the same manner as in Example 2. The multilayer ceramic capacitor chip was placed in the dummy scraped off from the magnetic drum. 250 capacitor chips were mixed.

[0021]

According to the present invention, a conductive paste containing a non-magnetic alloy composed of Ni, Co, and Fe can be provided. Therefore, the conductor obtained by using the conductive paste does not cause the "solder erosion" phenomenon, Since it is magnetic and has a similar thermal expansion coefficient to glass, silicon, etc., conductors suitable for various electronic components can be obtained by utilizing these properties, and the performance and performance of these electronic components can be obtained.
Productivity can be increased. For example, when a multilayer ceramic capacitor chip is manufactured, if used instead of Ni electrolytic plating provided on an Ag electrode, the underlying Ag
Even electrodes that are susceptible to “solder erosion”, such as electrodes, prevent this phenomenon and are non-magnetic, so they can be accurately separated when separated from dummy after barrel electrolytic solder plating, and the yield rate High, and productivity can be increased.

Claims (2)

(57) [Claims] 1. A Ni-containing nonmagnetic conductive paste containing a nonmagnetic alloy composed of Ni, Co, and Fe. 2. The non-magnetic conductive pen containing Ni according to claim 1.
Having a conductor obtained by baking the coated film of the paste
Electronic component with non-magnetic conductor.