JPH06168841A - Debinder method of laminated electronic part - Google Patents

Abstract

PURPOSE:To provide a debinder method in which crack or peeling does not occur after a debinder of a chip element. CONSTITUTION:A slurry is formed by mixing a dielectric porcelain powder and a binder solution, and a conductive pattern serving as an internal electrode is printed on green sheets obtained from the slurry, and a stacked body is formed by stacking up these sheets. After the stacked body is cut to a chip element with a predetermined size, the stacked body is loaded into a debinder oven, an internal pressure of the oven is increased to 10 atm, and then the temperature is increased at the rate of 20 deg.C per hour, and after the oven temperature reaches 200 deg.C, the pressure is started to reduce and is returned to an atmospheric pressure. Then, the oven temperature is kept at the peak temperature set according to the used binder for a certain time, and a debinder is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for debinding a laminated electronic component such as a laminated capacitor.

[0002]

2. Description of the Related Art A laminated electronic component such as a laminated capacitor has a conductor formed inside the laminated body so as to be superposed in the thickness direction. In order to manufacture such laminated electronic components, organic binders (ethyl cellulose, PVA, etc.), plasticizers (polyethylene glycol, etc.), dispersants (glycerin, ethyl oleate, etc.) and solvents (acetone, toluene, ethyl alcohol) are generally used. , Water, etc.) and a raw material powder are mixed to form a slurry, and a green sheet obtained from this is stacked with conductive patterns printed by screen printing or the like.

The obtained laminated body is cut and divided into desired dimensions to form chips, and the binder is usually removed before the chip element is fired to remove the organic binder and the like. This debinding is often performed mainly in a heated gas.

[0004]

By the way, when examining and examining the chip body after debinding, cracks and peeling may occur on the side surface. As a result of investigating the cause, the chip body expands. I found out that

That is, FIG. 2 is a graph showing the rate of expansion of a chip element body on which a certain conductive pattern is formed and a chip element body stacked without being formed, when the temperature is raised under normal pressure. In the case of this example, as the former curve 1 shows, the expansion reaches a peak when the temperature of the heating gas is 200 ° C. On the other hand, as a comparison, when the chip body having no conductive pattern is similarly measured, No swelling was observed, as the latter curve 2 shows.

From the above observation results, it is considered that the expansion occurs when the binder in the conductive pattern comes off from the chip body.

Therefore, an object of the present invention is to provide a debinding method in which cracks and peeling do not occur after debinding a chip element.

[0008]

DISCLOSURE OF THE INVENTION In view of the fact that the expansion of the chip body occurs when the binder comes out of the chip body, the inventors of the present invention conducted research and found that the expansion of the chip body was maximized. If the internal pressure of the debinding furnace is set higher than the atmospheric pressure until the temperature reaches the maximum temperature, and the internal pressure of the furnace is reduced from the maximum temperature to return to the atmospheric pressure, the expansion of the chip body can be suppressed. The present invention has been achieved by finding that the above-mentioned problems are solved.

Therefore, according to the present invention, a chip having a conductive pattern formed by stacking green sheets prepared from a slurry obtained by kneading a raw material powder and a binder solution and superposing the green sheets inside the obtained stack. In the debinding method for laminated electronic components, in which the material is charged into the debinding furnace and the temperature is increased to perform debinding, the internal pressure of the debinding furnace is higher than atmospheric pressure from room temperature to the temperature at which the expansion of the chip body is maximized. Is kept high, the furnace pressure is reduced from the temperature at which the expansion is maximized, the furnace pressure is returned to atmospheric pressure, and the temperature is continuously raised, and the furnace temperature is kept at a peak temperature set by the characteristics of the binder used for a certain period of time. The present invention provides a method for debinding a laminated electronic component, which comprises terminating the debinding.

[0010]

In the method of the present invention, the expansion of the chip body is severe, and the temperature is from room temperature to the temperature T _{max at} which the expansion is maximum.
Since the binder removal is performed under high pressure, the binder in the conductive pattern can be removed while suppressing the expansion of the chip body.

Since there is no expansion after T _max , the pressure is returned to atmospheric pressure so that the binder in the chip body can be easily removed. The reason why it is necessary to return from high pressure to normal pressure is that if it is done under high pressure to the end, gas will remain in the chip as it is, debinding will not proceed smoothly and carbonization will occur. Causes delamination and deterioration of sinterability during firing. Therefore, after the electrode binder has undergone initial decomposition and the internal gas is easily released to the outside, it is desirable to return to normal pressure.

[0012]

EXAMPLE FIG. 1 is a profile showing the relationship between the furnace pressure and the furnace temperature in the debinding furnace used in this example and the time. With reference to this figure, in this example, the multilayer chip capacitor is An example will be described below. (1) A dielectric ceramic powder and a binder solution are kneaded to prepare a ceramic slurry, and the slurry is processed into a sheet using a doctor blade method to form a ceramic green sheet. (2) A conductive paste is applied to the obtained ceramic green sheet by screen printing to form a conductive pattern to be an internal electrode. (3) The sheet on which the conductive pattern is formed is punched into a certain shape, and a plurality of the sheets are stacked to form a laminated body. (4) The laminated body is cut and divided into chip elements having a predetermined size, and these chip elements are loaded into a binder removal furnace. (5) After loading the chip body, as shown in FIG. 1, first, the internal pressure of the furnace is raised to 10 atm at room temperature and then 20 ° C.
The temperature is raised at a rate of / hr, and when the temperature inside the furnace reaches 200 ° C., decompression is started and the pressure is returned to atmospheric pressure.

On the other hand, the furnace temperature is kept at the peak temperature Tp set by the characteristics of the binder used for a certain period of time, and then the binder removal is completed.

The temperature at which the high pressure and the reduced pressure to be applied first are selected depending on the binder used in the conductive paste, and are not limited to the above 10 atm and 200 ° C.

[0015]

As described above, according to the method of the present invention, the expansion of the chip element body during the debinding process can be suppressed, so that a good laminated electronic component free from cracks and peeling after debinding can be obtained. Obtainable.

[Brief description of drawings]

FIG. 1 is a profile showing a relationship between furnace pressure and furnace temperature in a debinding furnace used in one example of the present invention, and time.

FIG. 2 is a graph showing a rate of expansion of a chip element body on which a conductive pattern is formed and a chip element body that is stacked without being formed when the temperature is raised under normal pressure.

[Explanation of symbols]

1 curve showing expansion coefficient of chip element with conductor pattern formed 2 curve showing expansion coefficient of chip element without laminated conductor pattern T _p peak temperature

Claims (1)

[Claims] 1. A green sheet prepared from a slurry obtained by kneading a raw material powder and a binder solution is laminated, and a chip material having a conductive pattern formed inside the obtained laminated body is removed. Charge into the binder furnace,
In a method for debinding a laminated electronic component in which debindering is performed by raising the temperature, the internal pressure of the debinding furnace is kept higher than atmospheric pressure from room temperature to a temperature at which the expansion of the chip body is maximized, and the expansion is maximized. From this temperature, the furnace pressure is reduced to return to atmospheric pressure and the temperature continues to rise, and the furnace temperature is kept at the peak temperature set by the characteristics of the binder used for a certain period of time to finish debinding. Debinding method for laminated electronic parts.