JP2010283164A - Method of manufacturing electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a laminated ceramic electronic component that suppresses elution of elements constituting a green sheet as ions and suppresses a defect of a capacitor element body, and whose breakdown voltage, dielectric loss, and high-temperature load lifetime are excellent. <P>SOLUTION: The method of manufacturing the electronic component having a dielectric layer consisting essentially of a perovskite compound represented by general formula ABO<SB>3</SB>, wherein A represents an element of an A site, B represents an element of a B site, and O represents an oxygen element includes a process of preparing a saturated solution of an ion of the element of the A site; a process for preparing an unbaked green chip including a green sheet to become the dielectric layer after baking; and a process for polishing the green chip in the saturated solution. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an electronic component, and more specifically, an electronic component that can effectively suppress defects (chips, chipping, etc.) of the electronic component and has good withstand voltage, dielectric loss, and high-temperature load life. It relates to the manufacturing method.

  Examples of electronic components mounted on electronic devices include multilayer ceramic electronic components such as capacitors, bandpass filters, inductors, multilayer three-terminal filters, piezoelectric elements, PTC thermistors, NTC thermistors, or varistors. ing. Capacitor element bodies constituting these multilayer ceramic electronic components are manufactured, for example, by simultaneously firing a green sheet and a green chip composed of a predetermined pattern of internal electrode pattern layers.

  The green chip thus obtained often has a rectangular parallelepiped shape. For this reason, chamfering is normally performed on the green chip in order to suppress component defects (chips, chipping, etc.) due to collision between components in the manufacturing process.

  For example, barrel polishing is used as the chamfering method. Barrel polishing includes dry barrel polishing and wet barrel polishing. Dry barrel polishing is a method of polishing an object without using a polishing liquid. In this dry barrel polishing, there is a problem that chipping and chipping are likely to occur in the polishing step because there is no water or an organic solvent that serves as a buffer during polishing.

  On the other hand, wet barrel polishing means that the object to be polished, a polishing liquid such as water or an organic solvent, and a medium such as a grinding stone as necessary are put into a container at a certain ratio, rotated, etc. This is a method of polishing by giving the motion. Thereby, a target object can be grind | polished because a target object and / or a target object and a medium mutually rub against each other.

  Patent Document 1 adopts wet barrel polishing for ceramic raw chips, puts a liquid such as water or inert solvent and ceramic raw chips into a container, and rotates or vibrates the corners of the ceramic raw chips. A method of rounding is disclosed.

  With such a wet barrel, it is possible to suppress component defects (chips, chipping, etc.) due to collision between components in the manufacturing process. However, conventionally, it has not been a problem that this wet barrel leads to a decrease in withstand voltage of electronic parts such as a capacitor obtained by firing a green chip and other electrical characteristics.

Japanese Patent Laid-Open No. 7-14743

  The present invention has been made in view of such a situation, and an object thereof is to provide a method for manufacturing an electronic component that suppresses chipping or chipping of the electronic component and has good withstand voltage, dielectric loss, and high temperature load life. It is to be.

As a result of intensive studies on the wet barrel, the present inventors have found the following problems and have completed the present invention. That is, the problem that the element which comprises a green sheet ionizes and elutes by using water as a polishing liquid was discovered. In particular, in a green sheet mainly composed of a compound represented by ABO ₃ containing an alkaline earth metal such as barium titanate, calcium titanate or strontium titanate, the cation (Ba ²⁺ ) constituting the A site is in water. It has been found that the A / B adjusted with the raw material changes due to the diffusion of A / B, and the A / B tends to decrease.

  Thus, when it becomes B site rich, sintering becomes easy to proceed and grain growth tends to proceed. As a result, the number of dielectric particles occupying one dielectric layer is reduced, and as a result, there are problems that grain boundaries are reduced and reliability such as withstand voltage, dielectric loss and high temperature load life is lowered.

Then, in order to solve the above-mentioned subject, the manufacturing method of the multilayer ceramic electronic component concerning the present invention,
A method of manufacturing an electronic component having a dielectric layer mainly composed of a perovskite compound represented by the general formula ABO ₃ in the case where A represents an A-site element, B represents a B-site element, and O represents an oxygen element. Because
Producing a saturated solution of ions of the element at the A site;
Preparing an unfired green chip including a green sheet that becomes the dielectric layer after firing;
Polishing the green chip in the saturated solution;
It is characterized by having.

  Preferably, the saturated solution is prepared at the highest temperature in the polishing process.

Preferably, the compound represented by ABO ₃ is at least one of BaTiO ₃ , CaTiO ₃ and SrTiO ₃ .

  Preferably, the method further includes a step of firing the green chip after the polishing step.

  Preferably, the saturated solution is a saturated aqueous solution.

  According to the present invention, by barrel-polishing the green chip under specific conditions, it is possible to suppress the elements constituting the green sheet from eluting as ions, and as a result, it is possible to suppress defects in electronic components, It is possible to provide a method for manufacturing an electronic component having good withstand voltage, dielectric loss, and high temperature load life.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 2A is a process schematic diagram showing a manufacturing process of the multilayer ceramic capacitor shown in FIG. FIG. 2b is a process schematic diagram showing a continuation process of FIG. 2a. FIG. 2c is a process schematic diagram showing a continuation process of FIG. 2b. FIG. 3A is a schematic front view of a horizontal centrifugal barrel machine used in the barrel polishing step of the multilayer ceramic capacitor manufacturing method according to one embodiment of the present invention, and FIG. 3B is shown in FIG. FIG. 3C is a schematic view of the horizontal centrifugal barrel machine viewed from the IIIB direction, and FIG. 3C is a cross-sectional view taken along the line IIIC-IIIC of the barrel container shown in FIG. 4A is a perspective view of the green chip before the barrel polishing step used for manufacturing the multilayer ceramic capacitor according to the embodiment of the present invention, and FIG. 4B is the barrel polishing step shown in FIG. It is the schematic sectional drawing which cut | disconnected the front green chip along the IVB-IVB line. FIG. 5A is a perspective view of a green chip after a barrel polishing process used for manufacturing a multilayer ceramic capacitor according to an embodiment of the present invention, and FIG. 5B is a barrel polishing process shown in FIG. It is the schematic sectional drawing which cut | disconnected the subsequent green chip along the VB-VB line. FIG. 6 is an enlarged cross-sectional view in which the corner portion VI of the green chip after the barrel polishing step shown in FIG. 5B is enlarged. 7A is a withstand voltage failure rate with respect to barrel polishing time in the method for manufacturing a multilayer ceramic capacitor according to one embodiment of the present invention, and FIG. 7B is a method for manufacturing the multilayer ceramic capacitor according to one embodiment of the present invention. 7C is a graph showing the relationship between the high temperature load life change rate and the barrel polishing time in the method of manufacturing a multilayer ceramic capacitor according to one embodiment of the present invention. FIG. 8 is a graph showing the relationship between the chip defect rate and the corner R value with respect to the polishing time in the barrel polishing step in the method for manufacturing a multilayer ceramic capacitor according to one embodiment of the present invention.

  The electronic component manufactured by the manufacturing method according to the embodiment of the present invention is not particularly limited, and examples thereof include a multilayer ceramic capacitor, a multilayer chip varistor, and a multilayer thermistor. In this embodiment, a multilayer ceramic capacitor is illustrated.

Overall Configuration of Multilayer Ceramic Capacitor As shown in FIG. 1, a multilayer ceramic capacitor 2 according to an embodiment of the present invention includes a capacitor element body 4 having a configuration in which dielectric layers 10 and internal electrode layers 12 are alternately stacked. Have. A pair of external electrodes 6 and 8 are formed on both side ends of the capacitor element body 4 so as to be electrically connected to the internal electrode layers 12 arranged alternately in the capacitor element body 4.

  The internal electrode layers 12 are laminated so that the side end faces are alternately exposed on the surfaces of the opposite end portions of the capacitor element body 4. The pair of external electrodes 6 and 8 are formed at both ends of the capacitor element body 4 and connected to the exposed end surfaces of the alternately arranged internal electrode layers 12 to constitute a capacitor circuit.

  The capacitor element body is manufactured, for example, by simultaneously firing a green chip composed of a green sheet and a predetermined pattern of internal electrode pattern layers. Hereinafter, the green sheet, the internal electrode pattern layer, and the green chip will be described.

Green Sheet The dielectric layer 10 in FIG. 1 is obtained by firing the green sheet 10a shown in FIG. 2a. The green sheet in the present invention has a perovskite compound represented by ABO ₃ (A is an A site element, B is a B site element, and O is an oxygen element) as a main component of the raw material. Specific examples of ABO ₃ include BaTiO ₃ , CaTiO ₃ , and SrTiO ₃ .

  Moreover, although it does not specifically limit as an accessory component, An alkaline-earth metal, a transition metal, a rare earth element, a glass composition etc. are mentioned, Specifically, the following compositions are mentioned.

A first subcomponent comprising at least one selected from MgO, CaO, BaO and SrO;
_Second subcomponent mainly containing SiO ₂ and containing at least one selected from MO (wherein M is at least one selected from Mg, Ca, Ba and Sr), Li ₂ O and B ₂ O ₃ When,
A third subcomponent including at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ,
The ratio of each subcomponent to 100 moles of the main component is
1st subcomponent: 0.1-5 mol,
Second subcomponent: 0.1-12 mol,
Third subcomponent: 0 to 0.3 mol (excluding 0),
The subcomponent which is is mentioned.

The subcomponent preferably further contains a fourth subcomponent containing at least one selected from MnO and Cr ₂ O ₃ , and the ratio of the fourth subcomponent to 100 mol of the main component is 0.00. It is 05-1.0 mol.

  The green sheet is obtained by forming a dielectric layer paste into a sheet shape. This paste is obtained by mixing and dispersing ceramic powder, solvent, dispersant, plasticizer, binder, and other components using a ball mill, bead mill, or the like.

Internal electrode layers 12 of the internal electrode pattern layer Figure 1 is obtained by firing the internal electrode pattern layer 12a shown in FIG. 2b. The conductive material contained in the internal electrode pattern layer 12a in the present invention is not particularly limited, but a base metal can be used because the constituent material of the dielectric layer 10 has reduction resistance. As the base metal used as the conductive material, Ni or Ni alloy is preferable. The Ni alloy is preferably an alloy of Ni and one or more elements selected from Mn, Cr, Co and Al, and the Ni content in the alloy is preferably 95% by weight or more.

  The internal electrode layer pattern layer 12a is obtained by forming the internal electrode layer paste into a predetermined pattern. The internal electrode layer paste is obtained by kneading a conductive powder, a solvent, a dispersant, a plasticizer, a binder, an additive powder, and the like with a ball mill or the like to form a slurry.

Green chip A green chip is obtained by forming the above-described dielectric layer paste and internal electrode layer paste as follows.

(Formation of green sheet 10a)
As shown in FIG. 2a, a dielectric layer paste is applied to the surface of a support sheet 20 made of, for example, a PET film by, for example, a doctor blade method to form a green sheet 10a. The green sheet 10a becomes the dielectric layer 10 shown in FIG. 1 after firing.

(Formation of internal electrode layer 12a)
Next, as shown in FIG. 2b, the internal electrode layer paste is applied to the surface of the green sheet 10a formed on the support sheet 20 in a predetermined pattern to form the internal electrode layer 12a. The internal electrode layer 12a becomes the internal electrode layer 12 shown in FIG.

  The method for forming the internal electrode layer 12a in FIG. 2b is not particularly limited as long as the layer can be formed uniformly. For example, a thick film forming method such as a screen printing method or a gravure printing method using an electrode layer paste, or Examples are thin film methods such as vapor deposition and sputtering.

  As shown in FIG. 2c, the green sheet 10a on which the internal electrode layer 12a is formed is peeled off from the support sheet 20 and sequentially laminated to form a laminate 24.

(Cutting of laminated body 24)
A plurality of green chips 42 are formed by cutting the laminate 24 into a lattice shape. The green chip 42 is solidified by removing some plasticizer by solidification drying.

Barrel Polishing Process FIG. 4A is a perspective view of the green chip 42. As shown in FIG. 4A, sharp corners and ridge lines are generated at the end of the green chip obtained after the cutting by the cutting process. Therefore, if the green chip is handled in this state, chipping or peeling of the laminate may occur before and after firing. Therefore, the green chip is solidified and dried, and then the green chip is subjected to wet barrel polishing to round the corners and ridgelines of the chip end.

  First, as shown in FIG. 3C, the solidified and dried green chip is put into the barrel container 54 together with the medium 56 and the polishing liquid. For example, by the horizontal centrifugal barrel machine 50 shown in FIG. Barrel polish.

(Polishing liquid adjustment)
In the present invention, the polishing liquid is a saturated solution of ions of A-site elements constituting the green sheet. Below, the adjustment method of polishing liquid is demonstrated.

The polishing liquid in the present invention is a saturated solution of ions of elements at the A site of the main component ABO ₃ of the dielectric layer of the multilayer ceramic electronic component. Therefore, the saturated solution can be obtained by immersing a substance containing the element at the A site in a solvent. The solvent only needs to dissolve the element at the A site, and examples thereof include water and a mixed solution of water and an organic solvent, preferably ion-exchanged water.

  The substance containing the element at the A site is preferably a green chip of an electronic component according to this manufacturing method. By using the green chip, it is possible to suppress the elution of each element component contained in the green sheet and the internal electrode pattern layer in addition to the element at the A site. In addition, examples of the substance containing an A-site element include compounds containing an A-site element, such as barium titanate or strontium titanate if the A-site element is Ba or Sr.

  Next, a substance containing the element at the A site is immersed in a solvent to prepare a saturated solution of ions of the element at the A site. At this time, the substance containing the element at the A site may be simply immersed in the solvent, or if the substance containing the element at the A site is the green chip of the electronic component according to the manufacturing method, barrel polishing is performed. You may get it. The saturated solution may be repeatedly used after filtration.

  Moreover, the temperature of the solvent when dissolving the substance containing the element at the A site is preferably the highest temperature in the polishing step, and is preferably 5 to 50 ° C., more preferably 25 to 40 ° C. In the polishing process, the temperature of the polishing liquid rises due to frictional heat, so that the solubility of ions of the element at the A site increases. For this reason, in order to suppress the elution of the ions of the A site elements in the polishing step more effectively, it is preferable to prepare a saturated solution of the ions of the A site elements at the highest temperature in the polishing step in advance.

  The method for confirming that the saturated solution has been reached is not particularly limited. For example, the concentration of the solvent at a certain time after the start of immersion is measured, and the concentration of elemental ions at the A site increases with respect to the immersion time. If no more can be seen, it may be determined that a saturated solution of elemental ion at the A site has been prepared.

  Moreover, the saturated solution of the element of A site obtained in this way can be repeatedly used by filtering.

(Barrel polishing)
As shown in FIG. 3A, in the horizontal centrifugal barrel machine 50, a barrel container 54 (partially omitted) is installed on a disk 52, and the center of the disk 52 is rotated (revolved) around the vertical axis. To do. In this embodiment, the barrel container 54 itself is configured not to rotate (rotate), but may be rotated. The embodiment of barrel polishing is not particularly limited.

  FIG. 3B is a schematic view of the horizontal centrifugal barrel machine 50 shown in FIG. 3A as viewed from above (IIIB direction). As shown in FIG. 3B, the same centrifugal force F acts on each barrel container 54 as the disc 52 rotates. Then, as shown in FIG. 3C, due to the action of the centrifugal force F, the green chip 42 is pressed against the outer peripheral side in the barrel container 52 together with the medium 56 and the polishing liquid, and flows while contacting the medium 56. To do.

  As a result, the corner portion and the ridge line portion of the green chip 42 that easily comes into contact with the medium 56 are cut and rounded (R portion). 3C is a cross-sectional view of the barrel container shown in FIG. 3A cut along the line IIIC-IIIC in FIG.

  The shape of the barrel container 54 is usually a cylindrical shape or a polygonal column shape, and may be appropriately changed depending on the polishing conditions. In the present embodiment, it is a hexagonal column shape. In the present embodiment, the inner wall of the barrel container 54 is made of urethane.

  The mass of the medium 56 is determined so that the ratio of the mass of one medium to the mass of one green chip is 0.1 to 6, but the medium 56 is not necessarily used in the present invention.

  The material and shape of the medium 56 are not particularly limited, and may be appropriately changed depending on polishing conditions. In the present embodiment, the material of the medium 56 is preferably ceramics or alloy steel. Further, the shape is preferably a highly symmetric shape such as a spherical shape. Also, the size of the medium 56 is not particularly limited, but when the medium 56 is spherical, the media diameter is preferably 1 to 5 mm.

  Moreover, the centrifugal acceleration which shows the magnitude | size of a centrifugal force can be adjusted by changing the rotation speed of the horizontal centrifugal barrel machine 50. FIG. The centrifugal acceleration is preferably 3.0 to 25G.

  By controlling the barrel polishing conditions, the green chip 42 before barrel polishing shown in FIGS. 4 (A) and 4 (B) is as shown in FIGS. 5 (A) and 5 (B) after barrel polishing. In addition, the corners and ridges of the green chip 42a are rounded.

The green chip 42 after the green chip firing barrel polishing step is washed with water and dried. The capacitor element body 4 shown in FIG. 1 is obtained by performing a binder removal process, a firing process, and an annealing process performed as necessary on the dried green chip.

Formation of External Electrode Capacitor element 4 obtained in this manner is subjected to end face polishing by sandblasting or the like, and external electrode paste is baked to form external electrodes 6 and 8. The conductive material contained in the external electrodes 6 and 8 is not particularly limited, but in the present invention, inexpensive Ni, Cu, and alloys thereof can be used. Further, the thicknesses of the external electrodes 6 and 8 may be appropriately determined according to the use and the like, but it is usually preferably about 10 to 50 μm.

  Then, if necessary, a pad layer is formed on the external electrodes 6 and 8 by plating or the like. The external electrode paste may be prepared in the same manner as the above internal electrode pattern layer paste. Since the above-described barrel polishing can sufficiently secure the coating thickness of the paste at the corner portion of the capacitor element 4, cracks during baking of the external electrodes can also be suppressed.

  The multilayer ceramic capacitor manufactured by the method according to the present invention is mounted on a printed circuit board by soldering or the like, and is used for various electronic devices.

In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change variously. For example, the present invention is not limited to a multilayer ceramic capacitor, and any electronic component having a dielectric layer whose main component is ABO ₃ may be used.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

Example 1
(Preparation of dielectric layer paste)
Prepare the BaTiO ₃ as a main component material, the first to fourth subcomponents below, was added, the dielectric by and wet mixed and pulverized by a ball mill to form slurry, and the slurry was dried, calcined and pulverized A body porcelain composition powder was obtained. In addition, the addition amount of each subcomponent is the addition amount in conversion of each oxide with respect to 100 mol of main components.

MgO (first subcomponent): 1.2 mol,
(Ba, Ca) SiO ₃ (second subcomponent): 0.75 mol,
V ₂ O ₅ (third subcomponent): 0.03 mol,
MnO (4th subcomponent): 0.1 mol.

  And 100 parts by weight of the dielectric ceramic composition powder obtained above, 6 parts by weight of polyvinyl butyral resin (PVB), 3 parts by weight of dioctyl phthalate (DOP) as a plasticizer, 60 parts by weight of methyl ethyl ketone, 40 parts by weight of ethanol and 20 parts by weight of toluene were wet mixed in a ball mill containing zirconia media having a diameter of 1 mm for 20 hours to obtain a paste for green sheets.

(Preparation of internal electrode layer paste)
Next, 44.6 parts by weight of Ni particles, 52 parts by weight of terpineol, 3 parts by weight of ethyl cellulose, and 0.4 parts by weight of benzotriazole are kneaded with three rolls to form a slurry for an internal electrode layer paste. Obtained.

(Production of multilayer ceramic capacitor)
A multilayer ceramic capacitor 1 shown in FIG. 1 was produced using the pastes prepared above as follows.

  First, a green sheet was formed on a PET film using the obtained dielectric layer paste. After the internal electrode layer paste was printed thereon, the sheet was peeled from the PET film. Subsequently, these green sheets and protective green sheets (not printed with the internal electrode layer paste) were laminated and pressure-bonded to obtain a laminate.

(Barrel polishing)
Next, the laminate was cut into a size of 1.6 mm × 0.8 mm × 0.8 mm to obtain a green chip. Thereafter, the green chip was solidified and dried.

Subsequently, the polishing liquid thrown into a barrel container was adjusted. Since the main component of the green sheet of this example is BaTiO ₃ , a saturated solution of Ba ²⁺ ions was prepared as a polishing liquid.

  The polishing liquid in this example was obtained by immersing a green chip having a green sheet having the above-described main component and subcomponent and an internal electrode pattern layer composed of the internal electrode layer paste in ion-exchanged water. .

Confirmation that the saturated aqueous solution of Ba ²⁺ ions could be adjusted was determined by measuring the concentration of Ba ²⁺ ions at regular intervals after the start of immersion, and when the increase in the Ba ²⁺ ion concentration reached its peak. did.

Next, 500 g of the green chip after solidification and drying, 1000 g of the medium 56, and the adjusted polishing liquid 16L were put into a 2 L barrel container. The media had a spherical shape, the material was a ceramic ball made mainly of alumina (Al ₂ O ₃ ) and silica (SiO ₂ ), and the size was 2 mm.

  Next, barrel polishing was performed by a horizontal centrifugal barrel machine 50. The centrifugal acceleration at this time was 3G.

  In this example, in order to investigate the effect of the polishing time on the defect of the capacitor sample and the characteristics of the capacitor sample, each green chip was obtained when the polishing time was 0, 15, 60, 360, and 960 minutes.

  Hereinafter, the firing process of the green chip and the formation process of the external electrode will be described, but the firing and formation of the external electrode were performed by the same method for the green chip of any polishing time.

(Green chip firing process)
The green chip 42 after barrel polishing was washed with water and dried. The dried green chip was subjected to binder removal processing, firing and annealing under the following conditions to obtain a capacitor element body 4.
Debinder treatment condition temperature increase rate: 32.5 ° C./hour,
Holding temperature: 260 ° C.
Temperature holding time: 8 hours,
Atmosphere: in the air.
Firing condition heating rate: 200 ° C./hour,
Holding temperature: 1260-1280 ° C
Temperature holding time: 2 hours,
Cooling rate: 200 ° C./hour,
Atmospheric gas: humidified N ₂ + H ₂ mixed gas (oxygen partial pressure: 10 ⁻⁷ Pa).
Annealing condition heating rate: 200 ° C./hour,
Holding temperature: 1050 ° C.
Temperature holding time: 2 hours,
Cooling rate: 200 ° C./hour,
Atmospheric gas: humidified N ₂ gas (oxygen partial pressure: 1.01 Pa).

  Note that a wetter with a water temperature of 20 ° C. was used for humidifying the atmospheric gas during firing and annealing.

(Formation of external electrodes)
The capacitor element body 4 thus obtained was subjected to end surface polishing by sandblasting or the like, and Cu was applied as an external electrode to form external electrodes 6 and 8.

  The size of the obtained capacitor sample is 1.6 mm × 0.8 mm × 0.8 mm, the number of dielectric layers sandwiched between internal electrode layers is 300, and the thickness of the dielectric layer per layer ( The interlayer thickness was 1.2 μm, and the thickness of the internal electrode layer was 1.2 μm.

  Subsequently, the withstand voltage failure rate, dielectric loss tan δ, and high temperature load life change rate of the capacitor samples were evaluated by the following methods. The results are shown in Tables 1 to 3 and FIG.

(Voltage failure rate)
With respect to 10,000 capacitor samples of each polishing time, the resistivity when a voltage of 150 V was applied was obtained, and the ratio of the number of capacitor samples having a resistivity of 10 ⁶ Ω or less was defined as the withstand voltage (withstand voltage) defect rate. .

(Dielectric loss tan δ)
With respect to 100 capacitor samples at each polishing time, with a digital LCR meter (YHP4274A manufactured by Yokogawa Electric Co., Ltd.) at a reference temperature of 20 ° C., the frequency is 1 kHz, the input signal level (measurement voltage) is 0. The dielectric loss tan δ was measured under the condition of 0.5 Vrms / μm, and the average value was obtained. The smaller the dielectric loss, the better.

(Change rate of high temperature load life (average life))
With respect to 1000 capacitor samples at each polishing time, the high temperature load life was measured by maintaining a DC voltage of 9.0 V / μm at 180 ° C. with respect to the capacitor sample, and the average value (average life) ) In this example, the time from the start of application until the insulation resistance drops by an order of magnitude was defined as the high temperature load life. Table 3 shows the change rate of the high temperature load life of the capacitor sample at each polishing time relative to the high temperature load life of the capacitor sample at a polishing time of 0 minutes.

Comparative Example 1
In barrel polishing, except that the polishing liquid is ion-exchanged water, the capacitor sample is prepared by the same method as the capacitor sample at each polishing time described above, and the corner chip R value of the green chip and the defective defect of the capacitor sample are obtained by the following method. The rate was evaluated. Further, the withstand voltage failure rate, dielectric loss tan δ, high temperature load life change rate, and chip failure rate of the capacitor samples were evaluated by the above methods. The results are shown in Tables 1 to 4 and FIGS. The chip defect rate and the corner R value were evaluated by the following methods.

(Defect rate)
With respect to 10,000 capacitor samples of each polishing time, four surfaces on which the counter electrode was not exposed were observed with a stereomicroscope to inspect for structural defects (chips, chipping, etc.). The smaller the defect defect rate, the better.

(Corner R value)
The shape of the corner after polishing was evaluated as follows. The polished green chip 42a shown in FIG. 5A was cut along the line VB-VB in FIG. Then, the cross section (FIG. 5B) was polished to the center of the green chip, the shape of the corner VI (FIGS. 5 and 6) was observed with a microscope, and the R value defined below was obtained. .

  That is, in FIG. 6, when a line perpendicular to the stacking direction is drawn from the apex of the green chip 42 before polishing, the length from the intersection of the line and the ridge line of the green chip 42a after polishing to the apex is expressed as X It was. Similarly, when a line parallel to the stacking direction was drawn from the apex, the length from the intersection of the line and the edge of the green chip 42a after polishing to the apex was defined as Y. R is an average value of X and Y, that is, R = (X + Y) / 2.

  From Tables 1 to 4 and FIGS. 7 and 8, when the polishing liquid is ion-exchanged water (single), the corner R value increases and the chip defect rate decreases as the polishing time increases, but the withstand voltage failure rate It was found that the dielectric loss and high temperature load life tend to deteriorate. However, when the polishing liquid is a saturated solution of Ba ions, even if polishing is performed with a sufficient polishing time to prevent chipping defects and the like, compared to the case where the polishing liquid is ion-exchanged water, It has been found that the deterioration of dielectric loss and high temperature load life can be suppressed.

2 ... Multilayer ceramic capacitor 4 ... Capacitor element body 6, 8 ... External electrode 10 ... Dielectric layer 10a ... Inner green sheet 11a ... Outer green sheet 12 ... Internal electrode layer 12a ... Internal electrode pattern layer 20 ... Support sheet 24 ... Laminate 42 ... Green chip 42a ... Green chip 50 ... Horizontal centrifugal barrel machine 52 ... Disc 54 ... Barrel container 56 ... Media

Claims (5)

A method of manufacturing an electronic component having a dielectric layer mainly composed of a perovskite compound represented by the general formula ABO ₃ in the case where A represents an A-site element, B represents a B-site element, and O represents an oxygen element. Because
Producing a saturated solution of ions of the element at the A site;
Preparing an unfired green chip including a green sheet that becomes the dielectric layer after firing;
Polishing the green chip in the saturated solution;
The manufacturing method of the electronic component which has this.   2. The method of manufacturing an electronic component according to claim 1, wherein the saturated solution is prepared at the highest temperature in the polishing step. _{3. The} method of manufacturing an electronic component according to claim 1, wherein the compound represented by ABO ₃ is at least one of BaTiO ₃ , CaTiO _3, and SrTiO ₃ .   The method for manufacturing an electronic component according to claim 1, further comprising a step of firing the green chip after the polishing step.   The method for manufacturing an electronic component according to claim 1, wherein the saturated solution is a saturated aqueous solution.

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