JP4743411B2 - Manufacturing method of laminated electronic component - Google Patents

Description

  The present invention relates to a method for manufacturing a laminated electronic component.

  In general, a multilayer electronic component such as a multilayer ceramic capacitor is manufactured by the following process. First, a dielectric paste obtained by adding a binder, a plasticizer, and a solvent to dielectric powder as a raw material is applied on a PET film to form a dielectric green sheet. Next, internal electrodes are printed on the dielectric green sheet. Further, a plurality of dielectric green sheets having internal electrodes are laminated and pressed to make a sheet laminate. Next, the sheet laminate is cut into a plurality of chip regions to obtain a laminated green chip. Further, the laminated green chip is subjected to binder removal processing for removing the binder and the like, and is fired under predetermined conditions. Thereafter, a known process such as terminal electrode formation is performed to obtain a laminated electronic component.

  In such a method of manufacturing a laminated electronic component, sharp edges due to the cutting process occur at the end of the laminated green chip obtained by cutting. There is a possibility that end face cracks such as chipping and peeling of the laminate occur before and after.

  Therefore, a technique is known in which the laminated green chip is barrel-polished to round the corners of the chip end.

Patent Document 1 proposes performing dry barrel polishing after thermally decomposing 20% to 80% of the plasticizer component contained in the laminated green chip. According to this document, chipping or peeling is likely to occur on the chip surface when the thermal decomposition rate of the plasticizer component exceeds 80%, and adhesion between chips occurs when the thermal decomposition rate is less than 20%. (See paragraph number 0019 of the same document). However, actually, even when the thermal decomposition rate of the plasticizer is about 20%, chipping or peeling of the laminate occurs.
JP 2004-172526 A

  An object of the present invention is to provide a method for manufacturing a laminated electronic component capable of reducing chip end face cracks and preventing adhesion between chips in barrel polishing.

  In order to solve the above-described problems, a method for manufacturing a laminated electronic component according to the present invention includes a step of solidifying and drying a laminated green chip, and then a step of barrel polishing the laminated green chip.

  In the step of solidifying and drying the laminated green chip, the decomposition amount of the plasticizer component contained in the laminated green chip is 7.0% to 14.4% based on the total amount of the resin binder component and the plasticizer component contained in the laminated green chip. A step of heat-treating the laminated green chip so as to be 0%.

  As described above, the method for manufacturing a multilayer electronic component according to the present invention includes a step of solidifying and drying the multilayer green chip, and then a step of barrel polishing the multilayer green chip. The solidification drying process of the laminated green chip plays a role of solidifying the laminated green chip so that the laminated green chip can be easily polished, and at the time of polishing, the plasticizer component in the laminated green chip is eluted into the solvent and the chips are separated from each other. Plays a role to prevent adhesion.

  The step of solidifying and drying the laminated green chip includes a step of performing a heat treatment on the laminated green chip. A part of the plasticizer component contained in the laminated green chip can be thermally decomposed by the heat treatment. According to the inventor's study, if the amount of decomposition of the plasticizer component is large, the laminated green chip becomes too hard and weak against impact, and end face cracks may occur frequently during barrel polishing. On the other hand, if the amount of decomposition of the plasticizer component is small, the residual organic component increases, and there is a risk that chips adhere to each other during barrel polishing.

  In the present invention, the decomposition amount of the plasticizer component contained in the laminated green chip is 7.0% to 14.0% based on the total amount of the resin binder component and the plasticizer component contained in the laminated green chip. Heat treatment is applied to the laminated green chip. According to the inventor's experiment, it was found that, within such a numerical range, it is possible to reduce chip end face cracks due to barrel polishing and to prevent adhesion between chips.

  As described above, according to the present invention, it is possible to provide a method for manufacturing a laminated electronic component capable of reducing chip end face cracks and preventing adhesion between chips in barrel polishing.

  Hereinafter, an embodiment when the present invention is applied to a method of manufacturing a multilayer ceramic capacitor will be described.

  First, a dielectric paste is prepared by adding a binder, a plasticizer and a solvent to a dielectric powder as a raw material. As the binder, butyral resin or the like can be used. As the plasticizer, dioctyl phthalate (dioctyl phthalate) can be used. Moreover, as a solvent, Solmix, n-propanol, xylene, etc. can be used.

  Next, a dielectric paste is applied on the PET film to form a dielectric green sheet. Further, a plurality of internal electrodes are formed on the dielectric green sheet with a conductive paste by a screen printing method or the like. Further, a plurality of dielectric green sheets having internal electrodes are laminated so that the positions of the internal electrodes are shifted and the positions where the internal electrodes are not shifted are alternately stacked, and pressed to produce a sheet laminate. In addition, as a method for producing a sheet laminate, a method for producing a sheet laminate by repeating a dielectric green sheet forming step and an internal electrode printing step on a flexible support as many times as necessary. Can also be adopted.

  Next, the sheet laminate is cut into a plurality of chip regions to obtain a laminated green chip. As a method for cutting the sheet laminated body, for example, a rotary blade cutting method is used in which a disk-shaped cutting blade is rotated to cut the sheet laminated body.

  FIG. 1 is a perspective view showing a laminated green chip obtained by cutting. As shown in the drawing, the laminated green chip has a rectangular parallelepiped shape defined by the length direction X, the width direction Y, and the thickness direction Z, and a plurality of internal electrodes 4 are formed in the dielectric substrate 2 with a thickness. The structure is embedded with an interval in the direction Z.

  As shown in the figure, a sharp corner 6 is generated at the end of the laminated green chip obtained by the cutting process. Therefore, if the laminated green chip is handled in this state, chipping or peeling of the laminate may occur before and after firing.

  Accordingly, the laminated green chip is solidified and dried, and then the laminated green chip is subjected to wet barrel polishing to round the corner 6 at the end of the chip.

  The step of solidifying and drying the laminated green chip includes a step of performing a heat treatment on the laminated green chip. A part of the plasticizer component contained in the laminated green chip can be thermally decomposed by the heat treatment. According to the inventor's study, when the amount of decomposition of the plasticizer component is large, the laminated green chip becomes too hard and weak against impact, and end face cracks may occur frequently during wet barrel polishing. However, when the amount of decomposition of the plasticizer component is small, the plasticizer component in the laminated green chip is eluted in the solvent during wet barrel polishing, and the chips may adhere to each other with this plasticizer component.

  In the present invention, the decomposition amount of the plasticizer component contained in the laminated green chip is 7.0% to 14.0% based on the total amount of the resin binder component and the plasticizer component contained in the laminated green chip. Heat treatment is applied to the laminated green chip. According to the inventor's experiment, it was found that within such a numerical range, cracks on the chip end face due to wet barrel polishing can be reduced and adhesion between the chips can be prevented.

  Note that by reducing the amount of decomposition of the plasticizer component, the elasticity of the laminated green chip increases, and even when the laminated green chip becomes difficult to polish, the barrel polishing time is longer than usual, for example, 1.5 times the usual. By setting to, the laminated green chip can be reliably polished.

  Next, a method for calculating the amount of thermal decomposition of the plasticizer component will be described.

  The amount of plasticizer decomposition was calculated from the change in weight during heat treatment at 400 ° C., based on the total amount of binder component and plasticizer component contained in the laminated green chip before heat treatment. Note that the solvent (Solmix, n-propanol, xylene) contained in the dielectric paste is almost volatilized in the process until the laminated green chip is cut, and therefore almost remains in the laminated green chip. It is thought that it is not.

表１に、固化乾燥条件による積層グリーンチップの重量変化率、可塑剤分解量を示す。固化乾燥条件「切断後、熱処理なし」では、切断後、熱処理を施していない積層グリーンチップを測定した。一方、固化乾燥条件「固化後、熱処理（１４０℃及び１時間）」では、固化後、１４０℃及び１時間の熱処理を施した積層グリーンチップを測定した。また、固化乾燥条件「固化後、熱処理（１８０℃及び１０時間）」では、固化後、１８０℃及び１０時間の熱処理を施した積層グリーンチップを測定した。 Table 1 below is a table showing the weight reduction rate of the laminated green chip and the amount of plasticizer decomposed by heat treatment according to the solidification drying conditions.

Table 1 shows the weight change rate and plasticizer decomposition amount of the laminated green chip depending on the solidification drying conditions. Under the solidification drying condition “after cutting, no heat treatment”, the laminated green chips that were not heat-treated after cutting were measured. On the other hand, under the solidification drying conditions “heat treatment after solidification (140 ° C. and 1 hour)”, the laminated green chip subjected to heat treatment at 140 ° C. and 1 hour after solidification was measured. In addition, under the solidification drying condition “heat treatment after solidification (180 ° C. and 10 hours)”, a laminated green chip subjected to heat treatment at 180 ° C. and 10 hours after solidification was measured.

  About the lamination | stacking green chip | tip of each solidification drying condition, the temperature rising process to 400 degreeC was performed with the thermogravimetry apparatus, and the weight reduction rate was calculated (refer the column of the weight reduction rate in Table 1).

  When the temperature raising treatment up to 400 ° C. is performed, the binder component and the plasticizer component contained in the laminated green chip are all decomposed or volatilized. The total amount can be obtained as the weight reduction rate due to the temperature raising process.

  When the thermal weight reduction rate of the laminated green chip “no heat treatment after cutting” was measured, it was 7.30%.

  Similarly, when the thermal weight reduction rate of the laminated green chip of “heat treatment after solidification (140 ° C. and 1 hour)” was measured to be 6.76%, 0.54% of the plasticizer was 140 ° C. and It is calculated that it was decomposed by heat treatment for 1 hour.

Therefore, the decomposition amount of the plasticizer component with respect to (binder component + plasticizer component) is calculated as follows.
(0.54 / 7.30) × 100 (%) = 7.4 (%)
Similarly, the amount of plasticizer decomposition can be calculated for the laminated green chip “heat treated (180 ° C. and 10 hours) after solidification”.

  When the thermal weight reduction rate of the laminated green chip without cutting after heat treatment is A, and the thermal weight reduction rate of the laminated green chip subjected to heat treatment after solidification is B, the plasticizer decomposition amount X by the heat treatment is expressed by the following formula: Given in.

実施例１〜３及び比較例１、２についてのデータは、次のようにして得た。 X = [(A−B) / A] × 100 (%) (1)
According to the formula (1), the amount of plasticizer decomposition was controlled by heat treatment conditions (140 to 160 ° C., 1 to 3 hours), and the end face cracks and chip adhesion amount were evaluated. The results are shown in Table 2 below.

Data for Examples 1 to 3 and Comparative Examples 1 and 2 were obtained as follows.

<Examples 1-3>
A dielectric paste containing butyral resin (abbreviated as PVB) as a binder component, dioctyl phthalate (abbreviated as DOP) as a plasticizer component, and solmix, n-propanol and xylene as solvents was prepared.

  Next, the multilayer green chip manufacturing process described above was performed using this dielectric paste to obtain a multilayer green chip.

  And the laminated | stacked green chip | tip after a cutting | disconnection was heated at 140 degreeC, the processing time was changed and the plasticizer decomposition amount was controlled.

  Next, 1000 g of the laminated green chip and 1500 g of the medium after heat treatment were put in a 2 L container and filled with pure water, and barrel polishing was performed for 240 minutes at 85 rpm. At that time, the adhesion state between the chips was examined.

  Thereafter, the laminated green chip was separated from the media, the laminated green chip was removed and fired, and the appearance of the obtained laminated chip was confirmed with a microscope.

<Comparative Examples 1 and 2>
In Comparative Example 1, the laminated green chip after cutting was subjected to heat treatment at 120 ° C. and 1.5 hours, and in Comparative Example 2, the laminated green chip after cutting was subjected to heat treatment at 180 ° C. and 10 hours. Other points were the same as those in Examples 1 to 3. In the same manner as in Examples 1 to 3, the state of adhesion between the chips was examined during barrel polishing. Furthermore, the external appearance of the obtained multilayer chip | tip was confirmed after baking.

  Furthermore, the above formula (1) was applied to each of Examples 1 to 3 and Comparative Examples 1 and 2, and the amount of decomposition of the plasticizer component relative to the total organic component was calculated from the thermal weight reduction rate. In addition, regarding the determination of chip adhesion, when the chip adhesion rate was less than 1000 ppm, it was judged as good (◯), and when it was 1000 ppm or more, it was judged as bad (Δ).

  From Table 2, when the plasticizer degradation amount is 7.0% or more, the chip adhesion result is good (Examples 1 to 3), but when the plasticizer degradation amount is less than 7.0%, the chip adhesion determination result is poor. (Comparative Example 1)

  In addition, when the plasticizer decomposition amount is 14.0% or less, the occurrence rate of end face cracks can be kept low (Examples 1 to 3), but when the plasticizer decomposition amount exceeds 14.0%, the occurrence rate of end face cracks. Increase rapidly (Comparative Example 2).

  Therefore, it can be seen that the amount of plasticizer decomposition should be 7.0% or more and 14.0% or less in order to reduce chip end face cracks and prevent adhesion between chips.

  Note that by reducing the amount of plasticizer decomposition, residual organic components increase, and even if chip-to-chip adhesion occurs, chip-to-chip adhesion can be achieved by separating the chip from the media while applying vibration. It is possible to avoid it.

It is a perspective view which shows the lamination | stacking green chip obtained by cutting.

Explanation of symbols

2 Dielectric substrate 4 Internal electrode

Claims (2)

A method for producing a laminated electronic component comprising a step of solidifying and drying a laminated green chip and then a step of barrel polishing the laminated green chip,
In the step of solidifying and drying the laminated green chip, the decomposition amount of the plasticizer component contained in the laminated green chip is 7.0% to 14.4% based on the total amount of the resin binder component and the plasticizer component contained in the laminated green chip. Including a step of heat-treating the laminated green chip so as to be 0%,
Furthermore, the heat treatment is performed in a range where the processing temperature is 140 ° C. or higher and 160 ° C. or lower and the processing time is 1 hour or longer and 3 hours or shorter,
The decomposition amount (X) of the plasticizer is defined as A, which is the thermal weight reduction rate of the laminated green chip obtained by pyrolyzing the total amount of the resin binder component and the plasticizer component, and the heat of the laminated green chip subjected to the heat treatment. When the weight reduction rate is B,
X = [(A−B) / A] × 100 (%)
Represented by
A method for manufacturing a laminated electronic component. A method for manufacturing a laminated electronic component according to claim 1 or 2,
The resin binder component is mainly composed of butyral resin,
The plasticizer is mainly composed of dioctyl phthalate,
A method for manufacturing a laminated electronic component.

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