JP2002219644A - Method for manufacturing ceramic electronic parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing ceramic electronic parts allowing reliably rounding a ridge part of a ceramic element and efficiently manufacturing the ceramic electronic parts with high reliability without occurrence of breaking, chipping or cracks. SOLUTION: The ceramic element 2 together with a grinding medium 3 are injected into a barrel 1 with a ratio of total volume of the ceramic element 2 and the grinding medium 3 within 20-50% of an inner volume of the barrel 1 and then the barrel 1 is rotated. In a process to grind/chamfer the ceramic element. 2, a volume ratio of the ceramic element 2 and the grinding medium 3 (=ceramic element/grinding medium) is set at 0.8 or smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a ceramic electronic component, and more particularly, to a method for manufacturing a ceramic electronic component including a step of polishing and chamfering a ceramic element.

[0002]

2. Description of the Related Art One of typical ceramic electronic components is, for example, a multilayer ceramic capacitor as shown in FIG. In this multilayer ceramic capacitor, a plurality of internal electrodes 52 are disposed so as to face each other with a ceramic layer 51 interposed therebetween, and one end of the ceramic element 60 is alternately drawn to different end faces. It has a structure in which a pair of external electrodes 53 are provided so as to be electrically connected to the internal electrodes 52.

Conventionally, a multilayer ceramic capacitor having such a structure is obtained by laminating a plurality of ceramic green sheets to which an internal electrode paste is applied, and pressing the laminated ceramic green sheets in a thickness direction (mother laminated body). Is formed, and this laminate is cut into individual ceramic elements, degreased and fired under predetermined conditions, and the ceramic element (sintered body) is externally attached to an end face from which the internal electrode is drawn out. Manufactured by applying electrodes.

Incidentally, in the multilayer ceramic capacitor manufactured by the above-mentioned conventional method, the capacitor element 6
Since the ridge line A of 0 (FIG. 3) is sharp (square),
The following problems may occur. If the ridge A forming the periphery of the end face from which the internal electrode 52 is drawn out is sharp, the coating thickness of the external electrode 53 becomes insufficient near the ridge A, and the ceramic element 60 closes the ridge A. When exposed, the external electrode 53 may be disconnected, and sufficient connection reliability cannot be secured. If the ridge A of the fired ceramic element 60 is sharp, it may be difficult to handle the ceramic element 60 during processing. In addition, chipping or cracking (so-called chipping) is likely to occur in the ridge line portion A, and careful handling is required, so that productivity is reduced.

Therefore, in order to solve such a problem, the edge of the ceramic element is conventionally rounded (chamfered) so that chipping hardly occurs and the thickness of the external electrode is made uniform. Is being done.

Conventionally, as a method for rounding (chamfering) a ridge portion of a ceramic element,
A wet barrel polishing method in which a ceramic element is put into a barrel (a rotating container) together with a polishing medium such as alumina balls, silica balls, zirconia balls, an abrasive, water, etc., and the barrel is rotated to perform polishing is widely used. ing.

According to this wet barrel polishing method,
The ridge of the ceramic element can be polished to make it round. However, in this wet barrel polishing method, cracks, chips, cracks, etc. are likely to occur in the ceramic element during the polishing process, and it is difficult to secure a high yield. For this reason, the rotation speed of the barrel has to be reduced, and the productivity is poor.

The present invention has been made to solve the above problems, and it is possible to surely round the ridge of the ceramic element, and further, the ceramic element is free from cracks, chips, cracks and the like during the polishing process. It is an object of the present invention to provide a method of manufacturing a ceramic electronic component that is unlikely to occur and can ensure a high yield with high productivity.

[0009]

In order to achieve the above-mentioned object, the present inventors have conducted various experiments and studies to find the ratio of the volume of the ceramic element to be polished to the volume of the barrel (rotating container) and the polishing. Knowing that the volume of the medium and the volume ratio of the ceramic element and the polishing medium affect the polishing effect and the occurrence of cracks, chips, cracks, etc. of the ceramic element in the polishing process, further repeated experiments and studies, and completed.

That is, a method of manufacturing a ceramic electronic component according to the present invention (claim 1) is a method of manufacturing a ceramic electronic component manufactured by firing a ceramic element and then providing an external electrode. The ceramic element and the polishing medium are charged into the barrel such that the total volume of the polishing medium is in the range of 20 to 50% of the inner volume of the barrel, and the barrel is rotated to polish and chamfer the ceramic element. The method is characterized in that a step of providing roundness to the ridge portion of the ceramic element is provided.

The ceramic element is put into the barrel together with the polishing medium so that the total volume of the ceramic element and the polishing medium is in the range of 20 to 50% of the inner volume of the barrel, and the barrel is rotated. The ceramic element can be reliably polished and chamfered, and the ridge portion can be rounded, while suppressing or preventing the element from cracking, chipping, or cracking.

It is preferable that the total volume of the ceramic element and the polishing medium is in the range of 20 to 50% of the internal volume of the barrel, because the total volume of the ceramic element and the polishing medium is 20% of the internal volume of the barrel. If less than, the movement of the ceramic element and the polishing medium will be random, it will not be possible to sufficiently round the ridge of each ceramic element,
If the total volume of the ceramic element and the polishing medium exceeds 50% of the internal volume of the barrel, the movement of the ceramic element and the polishing medium in the barrel becomes insufficient, and the ridge of each ceramic element may be sufficiently rounded. By being unable to do so.

According to a second aspect of the present invention, in the step of polishing and chamfering the ceramic element, the volume ratio of the ceramic element to the polishing medium (= ceramic element / polishing medium) is set to 0.8. It is characterized as follows.

In the step of polishing and chamfering the ceramic element, the ceramic element is efficiently polished by setting the volume ratio of the ceramic element to the polishing medium (= ceramic element / polishing medium) to 0.8 or less. It becomes possible to perform chamfering. If the volume ratio of the ceramic element to the polishing medium exceeds 0.8, the amount of the ceramic element with respect to the amount of the polishing medium becomes too large, and the number of times the polishing medium collides with the ceramic element decreases, and the ceramic element has a sufficient ridge line. Can not be rounded.

According to a third aspect of the invention, there is provided a method of manufacturing a ceramic electronic component, wherein the step of polishing and chamfering the ceramic element is performed after the step of firing the ceramic element.

By performing the step of polishing and chamfering the ceramic element after the step of firing the ceramic element, the edge of the ceramic element can be rounded to prevent occurrence of chipping. .

In a fourth aspect of the present invention, the step of polishing and chamfering the ceramic element is performed before the step of firing the ceramic element and in a dry manner. And

The step of polishing and chamfering the ceramic element is performed on the unfired ceramic element.
By performing the polishing in a dry manner, it becomes possible to prevent the occurrence of chipping by rounding the ridge portion of the ceramic element and to form a crack (gap) at the interface between the internal electrode and the ceramic. Can be prevented from occurring. The term “dry polishing” is a concept meaning that the polishing is performed in a state in which a liquid such as water, a solvent, and a dispersant does not substantially exist in the barrel.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be shown and features thereof will be described in more detail.

[Embodiment 1] In this embodiment 1, as shown in FIG. 1, a plurality of internal electrodes 12 are arranged so as to face each other with a ceramic layer 11 interposed therebetween. In this example, a multilayer ceramic capacitor having a structure in which a pair of external electrodes 13 and 13 are provided so as to be electrically connected to the internal electrodes 12 on both end surfaces of the ceramic element 2 drawn to the end surfaces on different sides is taken as an example. explain.

<Preparation of Ceramic Element> First, a plurality of ceramic green sheets each having an internal electrode pattern formed by applying an electrode paste are laminated, and further, a ceramic green sheet having no internal electrode pattern disposed on both upper and lower surfaces thereof. The sheets are stacked and pressed in the thickness direction to form a laminate (unfired mother laminate), and the mother laminate is cut to cut out individual unfired ceramic elements. The step of forming the ceramic element can be performed by a well-known method used in manufacturing a conventional multilayer ceramic capacitor.

<Barrel Polishing> Next, the unfired ceramic element is chamfered and barrel-polished to round the ridge A (FIG. 1). In carrying out this barrel polishing, first, as shown in FIG.
A barrel 1 having a polygonal cylindrical cross section in a direction orthogonal to the rotation axis X direction and having a bottom is prepared. In addition, barrel 1
A cover 1a is provided, and is configured to be rotatable around the center axis X as a rotation axis. Further, the inner surface of the barrel 1 has flexibility like, for example, a fluororesin,
In addition, it is preferable to use a material to which other substances are unlikely to adhere. This barrel 1 is not essentially different from that conventionally used for polishing a ceramic element in a process of manufacturing a ceramic electronic component.

Then, the ceramic element 2, the polishing medium 3, and the cushioning material 4 are charged into the barrel 1 at a predetermined ratio.

In the first embodiment, as the polishing medium 3, an alumina ball having a diameter of 4 mm and a
What mixed the silica ball of mm was used. There is no particular limitation on the type of the polishing medium, and zirconia balls or the like can be used.

As the buffer material 4, organic fine powder was used. Although 100 cc of the organic fine powder was introduced, in the case of the first embodiment, it is preferable that the organic fine powder be in the range of 50 to 150 cc.

In the first embodiment, the ceramic element 2 and the polishing medium 3 are barreled at such a ratio that the volume ratio of the ceramic element 2 to the polishing medium 3 (= ceramic element / polishing medium) becomes 0.5. 1 and the ratio of the total volume of the ceramic element 2 and the polishing medium 3 to the internal volume of the barrel 1 ((ceramic element volume +
The polishing medium volume) / the barrel inner volume) was changed at the ratio shown in Table 1.

[0027]

[Table 1]

Then, the ceramic element 2, the polishing medium 3,
The barrel 1 in which the buffer material 4 was loaded was rotated in the direction of arrow Y under the condition of 180 rpm × 20 minutes, so that barrel polishing of the ceramic element 2 was performed. Note that the barrel polishing was performed under a condition in which a liquid such as water, a solvent, and a dispersant does not substantially exist, that is, under dry conditions.

<Measurement of Chip / Crack Occurrence Rate> After barrel polishing under each condition was completed, the ceramic element was fired, and the resulting ceramic element (sintered body) 2 was examined for chip / crack occurrence rate. (However, the number of samples n = 500). The results are shown in Table 1.

As shown in No. 1 of Table 1, the ceramic element 2
Under the condition that the ratio of the total volume of the polishing medium 3 to the internal volume of the barrel 1 ((ceramic element volume + polishing medium volume) / barrel internal volume) is 0.15 (percentage: 15%), chipping / cracking occurs. Was observed. This is the ceramic element 2
Since the ratio of the total volume of the polishing medium 3 to the internal volume of the barrel 1 is small, the movement of the ceramic element 2 and the polishing medium 3 becomes random, and the ridge A of the ceramic element 2 can be sufficiently rounded. It is because there was not.

Also, as in Nos. 5 and 6, the ratio of the total volume of the ceramic element 2 and the polishing medium 3 to the internal volume of the barrel 1 ((ceramic element volume + polishing medium volume) / barrel internal volume) Was set to 0.6 (percentage: 60%) or more, chipping and cracking occurred. This is because the ratio of the total volume of the ceramic element 2 and the polishing medium 3 to the internal volume of the barrel 1 becomes too large, so that the ceramic element 2 and the polishing medium 3 become difficult to move in the barrel 1, and the ridge A has a sufficient roundness. This is because it was not possible to attach.

On the other hand, in the case of Nos. 2 to 4 within the scope of the present invention, the ridge A of the ceramic element 2 could be rounded without generating cracks or chips. As a result, a highly reliable ceramic electronic component in which the external electrode 13 was not disconnected at the ridge A of the ceramic element 2 could be efficiently manufactured. Table 1, N
In the case of o.3, when ((ceramic element volume + polishing medium volume) / barrel inner volume) was 0.3 (percentage: 30%), 1000 cc of water was added and wet barrel polishing was performed. No cracking was observed, but after firing of the ceramic element, cracks (cracks generated at the interface between the internal electrode and the ceramic) of 58% of the sample were observed. From the viewpoint of preventing the occurrence of such defects of the uki, it is preferable to perform the barrel polishing in a dry manner. However, in some cases, good results can be obtained even by wet polishing.

[Second Embodiment] In the second embodiment, barrel polishing was performed under the following conditions using the same ceramic element as that in the first embodiment. Therefore, the description of the configuration and the manufacturing method of the ceramic element is omitted here.

<Barrel Polishing> In the second embodiment, the same barrel 1 as that used in the first embodiment is used as the barrel.
(FIG. 2) was used. Further, as in the case of the first embodiment, a polishing medium and a buffer were also obtained by mixing alumina balls having a diameter of 4 mm, silica balls having the same diameter of 4 mm (polishing media), and organic fine powder (buffer). Using. The amount of the organic fine powder charged was 100 cc.

The ratio ((ceramic element volume + polishing medium volume / barrel internal volume)) of the total amount of the ceramic element volume and the polishing medium volume to the barrel internal volume is 0.40.
(Percentage: 40%), and the ceramic element and the polishing medium were changed so that the volume ratio of the ceramic element to the polishing medium (= ceramic element / polishing medium) became the volume ratio as shown in Table 2. Was.

[0036]

[Table 2]

Then, the barrel in which the ceramic element, the polishing medium, and the cushioning material have been charged is rotated under the condition of 180 rpm × 20 minutes in the same manner as in the first embodiment, and barrel polishing of the ceramic element 2 (dry barrel polishing) ) Was done.

<Measurement of Chip / Crack Occurrence Rate> After the barrel polishing under each condition was completed, the ceramic element was fired, and the resulting ceramic element (sintered body) was examined for the chip / crack occurrence rate. (However, the number of samples n = 500). The results are also shown in Table 2.

As shown in Nos. 5 and 6 in Table 2, under the condition that the volume of the ceramic element / the volume of the polishing medium was 1.0 or more, chipping or cracking was observed in the ceramic element. This is because the ratio of the ceramic element to the polishing medium became too large, the number of times the polishing medium collided with the ceramic element was reduced, and the ridge of the ceramic element could not be sufficiently rounded. .

On the other hand, Nos. 1 to 4 within the scope of the present invention
(Ceramic element volume / polishing medium volume = 0.2-0.
In the case of 8), without cracking or chipping,
The ridge of the ceramic element could be rounded.
As a result, a highly reliable ceramic electronic component in which the external electrode was not disconnected at the ridge of the ceramic element could be efficiently manufactured.

In the first and second embodiments, the case where the ceramic element is an unfired laminate used for manufacturing a multilayer ceramic capacitor has been described as an example.
INDUSTRIAL APPLICABILITY The present invention can be widely applied to a case where a ceramic element is polished in a manufacturing process of various ceramic electronic components and a ridge portion thereof is chamfered.

In the first and second embodiments, the case where the unfired ceramic element is polished and the ridge portion is chamfered is described as an example. However, the chamfer of the fired ceramic element may be chamfered depending on conditions. It is also possible to apply when performing.

In the first and second embodiments, the case where the barrel polishing is performed in a dry manner has been described. However, the present invention can be applied to the case where the barrel polishing is performed in a wet manner depending on conditions.

In the first and second embodiments, a barrel having a hexagonal cylindrical shape is used. However, in the present invention, there is no particular limitation on the shape of the barrel, and barrels having various known shapes may be used. Is possible.

In other respects, the present invention is not limited to the above-described embodiment. The type of the polishing medium and the buffer material, the specific shape and structure of the ceramic element to be polished, and the structure of the ceramic element Various applications and modifications can be made within the scope of the gist of the invention with respect to the type of ceramic to be formed, specific polishing conditions, and the like.

[0046]

As described above, according to the method for manufacturing a ceramic electronic component of the present invention (claim 1), the total volume of the ceramic element and the polishing medium is in the range of 20 to 50% of the inner volume of the barrel. The ceramic element is put into the barrel together with the polishing medium and the barrel is rotated, so that the ceramic element is reliably prevented while cracking, chipping, cracks, etc. are prevented and generated in the polishing process. By grinding and chamfering, it is possible to round the ridge. As a result, a highly reliable ceramic electronic component in which the external electrode is not disconnected at the ridge of the ceramic element can be manufactured with high yield.

Further, in the step of polishing and chamfering the ceramic element as in the method of manufacturing a ceramic electronic component according to claim 2, the volume ratio of the ceramic element to the polishing medium (= ceramic element / polishing medium) is set to 0.1. When it is 8 or less, it becomes possible to polish the chamfer efficiently and to perform chamfering. If the volume ratio of the ceramic element to the polishing medium exceeds 0.8, the amount of the ceramic element with respect to the amount of the polishing medium becomes too large, and the number of times the polishing medium collides with the ceramic element decreases, and the ceramic element has a sufficient ridge line. Can not be rounded.

Further, in the case where the step of polishing and chamfering the ceramic element is performed after the step of firing the ceramic element as in the method of manufacturing a ceramic electronic component according to the third aspect of the present invention, the ridgeline of the ceramic element is provided. The rounding of the portion can prevent chipping, which is significant.

Further, the step of polishing and chamfering the ceramic element as in the method of manufacturing a ceramic electronic component according to claim 4 is performed on the unfired ceramic element, and the polishing is performed in a dry manner, whereby the ceramic is obtained. By rounding the ridge of the element, it is possible to prevent the occurrence of chipping and to prevent the formation of cracks (gaps) at the interface between the internal electrode and the ceramic, that is, the occurrence of so-called uki. Thus, the present invention can be made more effective.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a ceramic electronic component (multilayer ceramic capacitor) manufactured by a method for manufacturing a ceramic electronic component according to an embodiment of the present invention.

FIG. 2 is a view showing one step (a barrel polishing step) of a method for manufacturing a ceramic electronic component according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a ceramic electronic component (multilayer ceramic capacitor) manufactured by a conventional method.

[Explanation of symbols]

 A Ridge line of ceramic element 1a Lid of barrel 1 Barrel 2 Ceramic element 3 Polishing medium 4 Buffer material (organic fine powder) 11 Ceramic layer 12 Internal electrode 13 External electrode X Rotation axis of barrel Y Arrow indicating rotation direction of barrel

(72) Inventor Kinya Aoki 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Yoshikazu Takagi 2-26-10 Tenjin, Nagaokakyo-shi Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Yasunobu Yoneda 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. (Reference) FG26 JJ03 JJ15 PP10

Claims (4)

[Claims] 1. A method for manufacturing a ceramic electronic component, comprising: providing an external electrode after firing a ceramic element, wherein the total volume of the ceramic element and the polishing medium is 20 to 50% of the inner volume of the barrel. A step of charging a ceramic element and a polishing medium into a barrel so as to be in a range, rotating the barrel, polishing and chamfering the ceramic element, and providing a rounded edge portion of the ceramic element. A method for producing a ceramic electronic component, comprising: 2. A polishing method according to claim 1, wherein in the step of polishing and chamfering the ceramic element, a volume ratio of the ceramic element to the polishing medium (= ceramic element / polishing medium) is set to 0.8 or less. Of manufacturing ceramic electronic components. 3. The method according to claim 1, wherein the step of polishing and chamfering the ceramic element is performed after the step of firing the ceramic element. 4. The method according to claim 1, wherein the step of polishing and chamfering the ceramic element is performed before the step of firing the ceramic element.
3. The method according to claim 1, wherein the dry process is performed.
The manufacturing method of the ceramic electronic component described in the above.