JP2011029272A - Method of manufacturing electronic component, and inspection method of electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electronic component for less variations in quality and improved yield by suppressing fluctuation in oxygen deficit quantity. <P>SOLUTION: The method for manufacturing the electronic component includes an annealing step in which an elemental body having an electrode and a sintered body containing perovskite type oxide is annealed so that the sintered body is oxidized. It includes a first measuring step of measuring Raman spectrum of the perovskite type oxide before an annealing step, a second measuring step of measuring Raman spectrum of the perovskite type oxide after the annealing step, and an evaluation step of acquiring a shift amount of a peak in a lattice oscillation region based on the Raman spectrums measured by the first measuring step and the second measuring step. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic component manufacturing method and an electronic component inspection method.

  Electronic components such as chip capacitors are usually manufactured by firing a laminate of a ceramic layer containing a dielectric and the like and an internal electrode such as a base metal. Thus, when baking a ceramic layer and an internal electrode simultaneously, in order to prevent the oxidation of the base metal which is a main component of an internal electrode, baking is performed in a reducing atmosphere. When firing in a reducing atmosphere in this manner, it is known that oxygen deficiency occurs in the oxide contained in the ceramic layer, and as a result, the insulation resistance and the like are significantly reduced. For this reason, annealing (reoxidation treatment) to compensate for oxygen deficiency is usually performed by performing reoxidation treatment on the sintered body after firing in a reducing atmosphere.

  If this re-oxidation treatment is performed at a high temperature for a long time, there is a problem that an electrode containing a base metal such as Ni is oxidized. For this reason, the reoxidation treatment is preferably performed at a low temperature and in a short time. On the other hand, the amount of oxygen vacancies in the above-described oxide has a great influence on the lifetime of electronic components. For this reason, it is necessary to establish a measurement technique capable of ascertaining the oxygen deficiency in the oxide as accurately as possible.

  However, since the amount of oxygen vacancies generated by firing in a reducing atmosphere is small, it is difficult to directly measure the amount of oxygen vacancies. For this reason, the present situation indirectly evaluates whether or not the amount of oxygen vacancies has been reduced by reoxidation treatment using a destructive test such as an accelerated life test. Thus, the fact that a method for directly grasping the amount of oxygen vacancies has not been established causes a decrease in yield and a prolonged manufacturing process, particularly in the mass production process of electronic components.

  Under such circumstances, for example, Non-Patent Document 1 proposes a method using a cathode luminescence method as a method for measuring the amount of oxygen deficiency in barium titanate.

G.Koschek and E.Kubalek, “Micron-scaled Spectral-ResolvedCathodoluminescence of Grains in Bariumtitanate Ceramics”, phys. Stat. Sol. (A) 79, 131, p.131-139, (1983)

  However, the method using the cathode luminescence method of Patent Document 1 described above is intended for pure barium titanate, and determines the amount of oxygen deficiency from the height of the peak. In this method, when a sintered body containing various components, such as a sintered body included in an electronic component, is used, the peak positions are different for each component, so that the peaks overlap each other. It is extremely difficult to specify the position and height of the peak corresponding to. For this reason, it is extremely difficult for the method of Patent Document 1 to measure the amount of oxygen vacancies in a sintered body containing a plurality of components.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an electronic component inspection method capable of easily measuring the amount of oxygen deficiency contained in an electronic component. In addition, the present invention provides a method for manufacturing an electronic component that can suppress a variation in the amount of oxygen vacancies and can improve the yield with little variation in quality.

  In order to achieve the above object, in the present invention, the manufacture of an electronic component including an element body, which includes an annealing step of oxidizing the sintered body by annealing the element body having a sintered body containing a perovskite oxide and an electrode. A first measurement step of measuring a Raman spectrum of a perovskite oxide before the annealing step, a second measurement step of measuring a Raman spectrum of the perovskite oxide after the annealing step, and a first measurement step And an evaluation step for obtaining a peak shift amount in the lattice vibration region from the respective Raman spectra measured in the second measurement step.

  In the method of manufacturing an electronic component according to the present invention, the amount of oxygen deficiency in the perovskite oxide is changed from the shift amount of the peak of the Raman spectrum measured before and after the annealing step without destroying the element body that becomes the electronic component. It can be measured easily. Therefore, according to the method for manufacturing an electronic component of the present invention, it is possible to manufacture an electronic component in which quality fluctuations are sufficiently suppressed with a high yield.

In the present invention, one of the reasons why the amount of oxygen vacancies in the perovskite oxide in a sintered body containing a plurality of components can be measured is that a Raman spectrum in the lattice vibration region is used. That is, in a piezoelectric material and a dielectric material, Raman spectroscopy has been conventionally used to analyze a phonon band structure, and a Raman spectrum in a wave number region of 1000 cm ⁻¹ or less has been used for this analysis. However, since the Raman spectrum belonging to such a region hardly changes even when the oxygen deficiency changes, it is extremely difficult to obtain information on the oxidation deficiency.

However, in the present invention, a Raman spectrum in a lattice vibration region of 1000 cm ⁻¹ or more, which is different from the wave number region used for phonon band analysis, is employed. The inventors have paid attention to such a wave number region, and found that the wave number of the peak appearing in the lattice vibration region varies depending on the change in the amount of oxygen vacancies in the perovskite oxide, thereby completing the present invention. It is a thing.

  In the present invention, it is preferable to adjust the annealing conditions in the annealing step according to the shift amount. This makes it possible to reduce the amount of oxygen vacancies in the perovskite oxide, further reducing the quality variation and further improving the yield.

  In another aspect, the present invention provides an inspection method for an electronic component comprising a sintered body containing a perovskite oxide and an electrode, the method comprising measuring a Raman spectrum in a lattice vibration region of the perovskite oxide Provide a part inspection method.

  According to the electronic component inspection method of the present invention, it is possible to easily measure the amount of oxygen vacancies contained in an electronic component without performing a destructive test of the electronic component. Therefore, for example, in an electronic component mass production process, if the electronic component inspection method of the present invention is performed, an electronic component including a sintered body with a sufficiently reduced amount of perovskite oxide oxygen vacancies can be stably supplied. Can do.

  In this invention, it is preferable to have the process of calculating | requiring the oxygen deficiency amount of a perovskite type oxide based on the measured shift amount of the peak of the said Raman spectrum. As a result, variations in the quality of electronic components are sufficiently reduced, and electronic components having a long life can be stably supplied.

  ADVANTAGE OF THE INVENTION According to this invention, the inspection method of the electronic component which can measure the oxygen deficiency amount contained in an electronic component easily and rapidly can be provided. In addition, it is possible to provide a method of manufacturing an electronic component that can improve the yield with less variation in quality by sufficiently suppressing fluctuations in the amount of oxygen deficiency.

It is a schematic cross section which shows the ceramic component sheet | seat used for the manufacturing method of the electronic component which concerns on suitable embodiment of this invention. It is sectional drawing which shows typically the element | base_body which has a sintered compact containing the perovskite type oxide and internal electrode used in the manufacturing method of the electronic component which concerns on suitable embodiment of this invention. It is sectional drawing which shows typically the multilayer ceramic capacitor obtained by the manufacturing method of the electronic component which concerns on suitable embodiment of this invention. It is a figure which shows the Raman spectrum before annealing in the sintered compact of the element body of Example 1, and the Raman spectrum after annealing. It is a graph which shows the annealing temperature-peak position relationship in Example 1 and Example 2. FIG. It is a graph which shows the annealing temperature-peak position relationship in Example 3 and Example 4. It is a figure which shows the Raman spectrum of the lattice vibration area | region before and behind annealing of the piezoelectric element of Example 5. FIG.

  In the following, preferred embodiments of the present invention will be described with reference to the drawings as the case may be. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  The method of manufacturing an electronic component according to the present embodiment includes an element forming step of forming an element having a sintered body containing a perovskite oxide and an electrode, and a Raman spectrum of the perovskite oxide included in the sintered body. A first measuring step for measuring, an annealing step for annealing the element body and re-oxidizing the sintered body, a second measuring step for measuring the Raman spectrum of the perovskite oxide, a first measuring step, and a second measuring step. An evaluation step for obtaining a peak shift amount in the lattice vibration region from each Raman spectrum measured in the measurement step, and an electrode formation step for obtaining an electronic component by forming a terminal electrode on the element body. Hereinafter, a case where a multilayer ceramic capacitor is manufactured as an example of an electronic component will be described.

  In the element forming process, first, a plurality of ceramic component sheets are prepared. FIG. 1 is a schematic cross-sectional view showing an example of a ceramic component sheet suitably used in the manufacturing method of the present embodiment. The ceramic component sheet 20 can be produced by the following procedure, for example.

  A paste containing a ceramic powder (ceramic paste) and a paste containing an electrode material (electrode paste) are applied on one surface 10a of the commercially available substrate film 10, respectively.

  The ceramic paste can be prepared, for example, by kneading a dielectric material (ceramic powder) and an organic vehicle. As the dielectric material, various compounds that become perovskite oxides upon firing, for example, carbonates, nitrates, hydroxides, organometallic compounds, and the like can be appropriately selected and used. Further, it may contain a perovskite oxide. As the dielectric material, a powder having an average particle size of 0.4 μm or less, preferably about 0.1 to 3.0 μm can be used.

  The electrode paste can be prepared by kneading a conductive material made of various conductive metals or alloys, various oxides, organometallic compounds, or resinates that become conductive materials after firing, and an organic vehicle.

  As the conductor material used when manufacturing the electrode paste, it is preferable to use Ni metal, Ni alloy, or a mixture thereof. In order to improve adhesion, the electrode paste may contain a plasticizer. Examples of the plasticizer include phthalic acid esters such as benzylbutyl phthalate (BBP), adipic acid, phosphoric acid ester, and glycols.

  The organic vehicle contained in the ceramic paste and the electrode paste is prepared by dissolving a binder resin in an organic solvent. Examples of the binder resin used in the organic vehicle include ethyl cellulose, acrylic resin, butyral resin, polyvinyl acetal, polyvinyl alcohol, polyolefin, polyurethane, polystyrene, or a copolymer thereof.

  As an organic solvent used for the preparation of the organic vehicle, for example, organic solvents such as terpineol, alcohol, butyl carbitol, acetone, toluene, xylene, and benzyl acetate can be used alone or in combination of two or more. Examples of the alcohol include methanol, ethanol, propanol and butanol.

  The ceramic paste may contain additives selected from various dispersants, plasticizers, antistatic agents, dielectrics, glass frit, insulators, and the like as necessary. In the manufacturing method of the present embodiment, the amount of oxygen vacancies can be measured with high accuracy even if a plurality of dielectric materials are included or components other than the dielectric materials are included.

  The above-mentioned ceramic paste is applied onto the surface 10a of the base film 10 by, for example, a doctor blade device. Then, the applied ceramic paste is dried in a commercially available drying apparatus at a temperature of, for example, 50 to 100 ° C. for 1 to 20 minutes to form a ceramic green sheet 22.

  Next, an electrode paste is printed on the surface 22a of the formed ceramic green sheet 22 so as to form a predetermined pattern using, for example, a screen printing apparatus. And the apply | coated electrode paste is dried for 1 to 20 minutes at the temperature of 50-100 degreeC in a commercially available drying apparatus, and the electrode green sheet 24 is formed. Thereby, the ceramic component sheet 20 in which the base film 10, the ceramic green sheet 22, and the electrode green sheet 24 are sequentially laminated can be obtained.

  Subsequently, using the produced ceramic component sheet 20, a laminate is produced according to the following procedure. The base film 10 of the ceramic component sheet 20 is peeled off to obtain the green sheet 26. The green sheet 26 and the ceramic component sheet 20 are laminated so that the surface 22b of the green sheet 26 and the electrode green sheet 24 of another ceramic component sheet 20 face each other. Thereafter, the base film 10 is peeled from the laminated ceramic component sheet 20. By repeating such a procedure and laminating the green sheets 26, a laminate can be obtained. That is, after laminating the ceramic component sheet 20 on the green sheet 26, a laminate is produced by repeating the procedure of peeling the base film 10 a plurality of times.

  There is no restriction | limiting in particular in the number of lamination | stacking of the green sheet in a laminated body, For example, tens to hundreds of layers may be sufficient. A thick exterior green sheet on which no electrode layer is formed may be provided on both end faces orthogonal to the stacking direction of the stack. This exterior green sheet can be composed of the same components as the ceramic green sheet 22. Moreover, after forming a laminated body, a laminated body is cut | disconnected and it is good also as a green chip.

Next, an element body including a sintered body and an electrode is obtained by firing the laminate (green chip) obtained by the above-described procedure. The firing condition is, for example, 1100 to 1300 ° C. in a reducing atmosphere such as a mixed gas containing humidified nitrogen and hydrogen. The oxygen partial pressure in the atmosphere during firing is preferably 10 ⁻² Pa or less, more preferably 10 ⁻² to 10 ⁻⁸ Pa, in order to suppress oxidation of the metal contained in the electrode green sheet 24. Note that before the firing, it is preferable to perform a binder removal treatment on the laminate. The binder removal process can be performed under normal conditions. For example, when a base metal such as Ni or Ni alloy is used as the conductor material of the internal electrode (electrode green sheet 24), it is preferably performed at 200 to 600 ° C.

  FIG. 2 is a cross-sectional view schematically showing an element body having a sintered body containing a perovskite oxide and an internal electrode, which is produced in the element body forming step in the method of manufacturing an electronic component of the present embodiment. As described above, the element body 100 is obtained by firing the laminated body in a reducing atmosphere. The element body 100 includes an interior portion 40 in which ceramic layers 42 and internal electrodes 44 that are sintered bodies are alternately stacked, and a pair of exterior portions 50 made of a sintered body so as to sandwich the interior portion 40 in the stacking direction. And have.

  In the element forming process, as described above, the element body 100 is formed by firing the laminate. By performing this firing in a reducing atmosphere, oxidation of the base metal contained in the internal electrode 44 can be suppressed. On the other hand, oxygen defects are likely to occur in the sintered body (ceramic layer 42) containing the perovskite oxide. For this reason, in the manufacturing method of this embodiment, the oxygen defect amount contained in a sintered compact is reduced by the following processes.

In the first measurement step, the Raman spectrum of the sintered body provided in the element body 100 is measured. For the measurement, an ordinary commercially available measuring apparatus can be used. The Raman spectrum is measured in the wave number region including the lattice vibration region of the perovskite oxide included in the sintered body. Lattice vibration region varies depending on the kind of perovskite type oxide, usually, 1000 cm ^-1 or more, preferably a wave number region of 1000~4000cm ^-1.

The wave number (peak position) of the peak of the Raman spectrum in the lattice vibration region differs depending on the type of perovskite oxide contained as a main component in the sintered body and the types of subcomponents different from the main component. around 1450 cm ^-1 in the case component barium titanate, peak near 2300 cm ^-1 in the case of lead titanate are detected, respectively.

In the annealing step, the element body 100 is annealed (heat treated) to re-oxidize the sintered body. Thereby, oxygen is supplemented to the crystal structure of the sintered body, and the amount of oxygen vacancies is reduced. As annealing conditions in the annealing step, annealing temperature, annealing time, annealing atmosphere and the like can be mentioned. The annealing temperature of the element body 100 in the annealing step is preferably 700 to 1100 ° C., and the annealing time maintained at the temperature is preferably 1 to 5 hours. The annealing atmosphere is an oxygen partial pressure higher than that of the reducing atmosphere during firing, and preferably an atmosphere having an oxygen partial pressure of 10 ^{−2 to 1} Pa. Specifically, a mixed atmosphere of nitrogen and air may be used. The annealing conditions are preferably adjusted based on the shift amount in the evaluation process described later.

  In the second measurement step, the Raman spectrum of the sintered body provided in the annealed element body is measured. The measurement is preferably performed under the same measurement conditions using the same measurement equipment as in the first measurement step. Also in the second measurement step, the Raman spectrum of the wave number region including the lattice vibration region of the perovskite oxide included in the sintered body is measured as in the first measurement step.

  In the evaluation step, the peak shift amount in the lattice vibration region is obtained from the Raman spectra measured in the first measurement step and the second measurement step. According to this shift amount, it can be evaluated whether or not the oxygen deficiency amount of the sintered body is reduced by the annealing step. That is, in the lattice vibration region, if the peak of the Raman spectrum detected in the first measurement process is shifted to a higher wave number side than the peak of the Raman spectrum detected in the second measurement process, sintering is performed by the annealing process. It can be determined that the amount of oxygen deficiency in the body is reduced. The shift amount can be obtained as a wave number width in which the peak apex has moved before and after the annealing step.

  When the shift amount of the peak of the Raman spectrum in the lattice vibration region is small, it can be determined that the oxygen deficiency amount is not sufficiently reduced. In this case, the annealing process may be performed again to re-oxidize the sintered body. In addition, when mass producing electronic components, it is possible to quickly avoid the production of defective products in which the amount of oxygen deficiency is not reduced by adjusting the heat treatment conditions such as temperature and time in the annealing process. As described above, according to the manufacturing method of the present embodiment, the amount of oxygen vacancies in the sintered body can be measured easily and quickly, so that variation in quality is reduced and long-life electronic components are manufactured with high yield. be able to.

  In the electrode forming step, end face polishing is performed by, for example, barrel polishing, sand blasting, or the like on an element body including a sintered body in which the amount of oxygen deficiency is sufficiently reduced and an internal electrode. And a multilayer ceramic capacitor can be obtained by baking a terminal electrode paste on the side surface of the element body to form a terminal electrode.

  FIG. 3 is a schematic cross-sectional view showing a multilayer ceramic capacitor obtained by the manufacturing method of the present embodiment. A multilayer ceramic capacitor 200 shown in FIG. 3 includes an interior portion 40 and a pair of exterior portions 50 that sandwich the interior portion 40 in the stacking direction. In the present embodiment, the multilayer ceramic capacitor 200 has terminal electrodes 60 on the side surfaces facing each other.

  The interior portion 40 includes a plurality of (13 layers in this embodiment) ceramic layers 43 and a plurality (12 layers in this embodiment) of internal electrodes 44 that are sintered bodies. The ceramic layers 43 and the internal electrodes 44 are alternately stacked. Further, the internal electrodes 44 electrically connected to one terminal electrode 60 and the internal electrodes 44 electrically connected to the other terminal electrode 60 are alternately stacked.

  The exterior part 50 is formed of a ceramic layer. This ceramic layer is formed from a green sheet for exterior (sintered body) and contains, for example, the same components as the ceramic layer 43.

  The perovskite oxide contained in the sintered body (ceramic layer 43) of the multilayer ceramic capacitor 200 is supplemented with oxygen by an annealing process. In the manufacturing method of the present embodiment, oxygen supplementation in the annealing process is reliably performed by the first measurement process and the second measurement process, so that the amount of oxygen vacancies in the sintered body can be sufficiently reduced. That is, the amount of oxygen vacancies in the ceramic layer 43 of the multilayer ceramic capacitor 200 is sufficiently reduced as compared with the ceramic layer 42 of the element body 100. Therefore, a decrease in insulation resistance of the ceramic layer 43 is sufficiently suppressed, and a multilayer ceramic capacitor having a long life can be obtained.

  Next, a preferred embodiment according to the electronic component inspection method of the present invention will be described below.

  The electronic component inspection method according to the present embodiment includes a preparation step of preparing an electronic component having a sintered body containing a perovskite oxide and an electrode, and a Raman in a lattice vibration region of the perovskite oxide included in the sintered body. And an inspection process for measuring the spectrum.

  As an electronic component having a sintered body containing a perovskite oxide and an electrode, an element body 100 shown in FIG. 2 or a multilayer ceramic capacitor 200 shown in FIG. 3 can be used. The element body 100 or the multilayer ceramic capacitor 200 can be manufactured by the above-described manufacturing method.

  When the element body 100 is used as an electronic component, in the inspection process, a Raman spectrum in the lattice vibration region of the perovskite oxide included in the sintered body (ceramic layer 42) of the element body 100 is measured. From the wave number (peak position) of the peak of the Raman spectrum in this lattice vibration region, the amount of oxygen vacancies in the sintered body can be determined. At this time, if a calibration curve showing the correlation between the oxygen deficiency amount and the peak position is prepared in advance for a sintered body having a specific composition, the amount of oxygen deficiency in the sintered body having an equivalent composition is determined. It is also possible to do.

  The element body 100 may be reoxidized according to the result of the Raman spectrum in the inspection process. Thereafter, the Raman spectrum in the lattice vibration region of the perovskite oxide included in the element body 100 is measured, and the peak position of the Raman spectrum before the reoxidation treatment is compared with the peak position of the Raman spectrum after the reoxidation treatment. The presence or absence of a reduction in oxygen deficiency can be determined. It is also possible to quantify the amount of oxygen deficiency in the sintered body.

  As described above, the inspection method of the present embodiment can determine the oxygen deficiency amount in the sintered body easily, quickly and with high accuracy without destroying the electronic component. Therefore, it is particularly useful as a mass production inspection method from the viewpoint of yield improvement, quality variation reduction, and manufacturing process shortening.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, although the multilayer ceramic capacitor has been described in the above embodiment, for example, a multilayer piezoelectric element including a piezoelectric ceramic made of a sintered body containing a perovskite oxide and an electrode may be used. That is, if the electronic component includes a sintered body containing a perovskite oxide and an electrode, the effects of the present invention can be enjoyed by applying the manufacturing method or the inspection method of the present invention.

  Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.

(Examples 1 and 2)
<Preparation of element body>
As raw materials, BaTiO ₃ based ceramic powder, additives shown in Table 1, polyvinyl butyral (PVB) as an organic binder, and methanol as a solvent were prepared. Next, 10 parts by weight of an organic binder and 130 parts by weight of a solvent were kneaded with a ball mill to form a slurry with respect to 100 parts by weight of the ceramic powder.

  A dielectric green sheet was formed by applying a dielectric slurry on a commercially available base film so that the thickness of the fired ceramic layer was 1.0 μm. Next, Ni paste was printed on the dielectric green sheet and dried to obtain a ceramic component sheet 20 having a green sheet 26 as shown in FIG.

  A plurality of green sheets 26 obtained by peeling the base film 10 from the ceramic component sheet 20 were laminated to produce a laminate. On the end face perpendicular to the stacking direction of the stack, an exterior green sheet on which no electrode layer was formed was stacked. The laminated body thus obtained was cut into a predetermined size to obtain a green chip. The green chip was debindered and then fired under predetermined conditions to obtain an element body 100 as shown in FIG. In Example 1, firing was performed at 1150 ° C. for 1 hour in a mixed gas atmosphere of nitrogen and hydrogen (hydrogen content: 3% by volume). On the other hand, in Example 2, firing was performed at 1200 ° C. for 1 hour in a mixed gas atmosphere of nitrogen and hydrogen (hydrogen content: 1% by volume). The composition of the sintered body included in the element body 100 of Example 1 and Example 2 was as shown in Table 1.

<Measurement of Raman spectrum>
A plurality of element bodies 100 of Example 1 and Example 2 were prepared, and a Raman spectrum of the ceramic layer 42 portion of each element body 100 was measured using a commercially available Raman spectroscopic analyzer. The measurement was performed for the wave number including the lattice vibration region of barium titanate, and the peak position (wave number: cm ⁻¹ ) in the lattice vibration region was obtained.

<Annealing treatment and measurement of Raman spectrum>
Next, reoxidation treatment (annealing) of 200 to 1050 ° C. for 2 hours was performed on each element body in a mixed gas atmosphere of nitrogen and air (oxygen partial pressure: 10 ⁻¹ Pa). The Raman spectrum of the ceramic layer portion of the element body after annealing was measured again, and the peak position (wave number: cm ⁻¹ ) in the lattice vibration region was determined. Table 2 shows the measurement results of the peak wavenumber (peak position) before and after annealing and the peak shift amount. FIG. 4 shows the Raman spectrum before annealing (dotted line) and the Raman spectrum after annealing (annealing temperature: 800 ° C., solid line) in the sintered body of the base body of Example 1. In FIG. 4, the peak shift amount associated with the reoxidation process is “a”.

  FIG. 5 is a graph showing the annealing temperature-peak position relationship in Example 1 and Example 2. In FIG. 5, the value at the annealing temperature of 0 ° C. indicates the wave number of the peak before annealing. From the results of FIG. 5, it was confirmed that the peak of the Raman spectrum in the lattice vibration region shifts to the high wavenumber side by annealing at 600 ° C. or higher in the compositions of Example 1 and Example 2.

<Insulation test>
Between the adjacent internal electrodes 44 of each element body after annealing, the resistance value of the sintered body (ceramic layer 42) was measured. The measurement was performed by placing the element body in a temperature environment of 25 ° C. and 180 ° C., respectively. The results were as shown in Table 3.

  As shown in Table 3, it was confirmed that the insulation resistance of the sintered body was improved by annealing. In particular, when the annealing temperature was 700 to 1000 ° C., the insulation resistance of the sintered body could be increased.

<HALT test>
Next, the HALT test of each element body after annealing was performed according to the following procedure. The annealed element was heated to 140 ° C., and a voltage of 40 V was applied between adjacent internal electrodes 44. After confirming that the resistance value of the sintered body (ceramic layer 42) is 1 × 10 ⁵ Ω or more, the voltage is continuously applied, and the time until the resistance value decreases by an order of magnitude from the initial value is determined. It was measured. The results were as shown in Table 3.

As shown in Table 4, it was confirmed that the insulation resistance could be kept high for the longest time when the annealing temperature was 800 ° C. On the other hand, the sintered body of the element body before annealing had low insulation resistance from the beginning, and the initial value was less than 1 × 10 ⁵ Ω. This is due to the large amount of oxygen defects in the sintered body. It was confirmed that by setting the annealing temperature to 600 ° C. or higher, the amount of oxygen vacancies in the sintered body was sufficiently reduced, and an electronic component (multilayer ceramic capacitor) having a long life was obtained.

(Examples 3 and 4)
Element bodies of Examples 3 and 4 were produced using the same raw materials as in Examples 1 and 2. The sintering conditions were the same as in Example 2 for both Example 3 and Example 4. Thereafter, the Raman spectrum of the sintered body was measured in the same manner as in Examples 1 and 2, and the peak wave number (peak position) in the lattice vibration region was obtained. Furthermore, annealing was performed in the same manner as in Example 2, the Raman spectrum of the sintered body after the annealing treatment was measured, and the wave number of the peak in the lattice vibration region was obtained. The amount of peak shift accompanying annealing was also obtained. These results were as shown in Table 5.

  FIG. 6 is a graph showing the annealing temperature-peak position relationship in Example 3 and Example 4. In FIG. 6, the value of the annealing temperature “0 ° C.” indicates the peak position before annealing. From the results of FIG. 6, in Example 3 and Example 4 as well as Example 1 and Example 2, as the annealing temperature increases, the peak position of the Raman spectrum in the lattice vibration region shifts to the high wavenumber side. It was confirmed that It was confirmed that the amount of oxygen vacancies in the sintered body was reduced by performing re-oxidation at an annealing temperature of 600 to 1000 ° C.

(Example 5)
<Production of piezoelectric element>
As starting materials, powder materials of lead oxide (PbO), titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), and niobium oxide (Nb ₂ O ₅ ) were prepared. These raw materials are made into a piezoelectric ceramic composition having a composition of Pb [(Zn _1/3 Nb _2/3 ) _0.1 (Ti _0.5 Zr _0.5 ) _0.9 ] O ₃ after firing. Each starting material was weighed and blended to prepare a mixed material.

Next, the prepared mixed raw material and pure water were mixed with a Zr ball by a ball mill for 10 hours to obtain a slurry. This slurry was sufficiently dried and then press-molded, and calcined at 900 ° C. to obtain a calcined product. Next, the calcined product was finely pulverized with a ball mill, and then dried, and then an appropriate amount of PVA (polyvinyl alcohol) as a binder was added and granulated. The granulated powder was used in place of the BaTiO ₃ ceramic powder, and a piezoelectric slurry containing the granulated powder was prepared in the same manner as in Example 1.

  A piezoelectric green sheet was formed by applying a piezoelectric slurry on a commercially available substrate film so that the thickness of the fired piezoelectric ceramic layer was 100 μm. Next, a Cu paste was printed on the piezoelectric green sheet and dried to obtain a ceramic component sheet 20 having a green sheet 26 as shown in FIG. And the laminated body and the green chip were produced like Example 1. FIG.

The produced green chip was subjected to binder removal processing and then fired under predetermined conditions to obtain an element body similar to the element body 100 shown in FIG. Firing was performed by heating at 950 ° C. for 10 hours in a mixed gas atmosphere of nitrogen and hydrogen (hydrogen content: 100 ppm). Thus, sintering containing as a main component a piezoelectric ceramic composition having a composition of Pb [(Zn _1/3 Nb _2/3 ) _0.1 (Ti _0.5 Zr _0.5 ) _0.9 ] O _3. A laminated piezoelectric element having a body (piezoelectric layer) was obtained.

<Measurement of Raman spectrum>
Using a commercially available Raman spectroscopic analyzer, the Raman spectrum of the sintered body portion (piezoelectric ceramic layer) of the piezoelectric element produced as described above was measured. The measurement was performed for the wave number including the lattice vibration region of PZT, and the peak wave number (peak position) in the lattice vibration region was obtained.

<Annealing treatment and measurement of Raman spectrum>
Next, re-oxidation treatment (annealing) was performed for 2 hours in an atmosphere of mixed gas of nitrogen and air (oxygen partial pressure: 10 ⁻⁵ Pa) at an annealing temperature of 800 ° C. The Raman spectrum of the piezoelectric ceramic part in the annealed piezoelectric element was measured again to determine the peak wave number (peak position) in the lattice vibration region.

  FIG. 7 is a diagram showing the Raman spectrum of the lattice vibration region before and after annealing of the sintered body in the piezoelectric element of Example 5. FIG. 7 shows the Raman spectrum before annealing of the piezoelectric ceramic in the piezoelectric element of Example 5 (dotted line) and the Raman spectrum after annealing (annealing temperature: 800 ° C., solid line). As is clear from FIG. 7, it was confirmed that in the piezoelectric ceramic, the amount of oxygen defects was reduced and the peak position was shifted by the reoxidation treatment. In FIG. 7, the peak shift amount is “a”.

  DESCRIPTION OF SYMBOLS 10 ... Base film, 20 ... Ceramic component sheet, 22 ... Ceramic green sheet, 24 ... Electrode green sheet, 26 ... Green sheet, 40 ... Interior part, 42, 43 ... Ceramic layer, 44 ... Internal electrode, 50 ... Exterior part , 60 ... terminal electrodes, 100 ... element body, 200 ... multilayer ceramic capacitor.

Claims (4)

An electronic component manufacturing method including an annealing step of annealing a sintered body including a perovskite-type oxide and an electrode and oxidizing the sintered body,
A first measurement step of measuring a Raman spectrum of the perovskite oxide before the annealing step;
A second measurement step of measuring a Raman spectrum of the perovskite oxide after the annealing step;
An evaluation method for obtaining a peak shift amount in a lattice vibration region from the respective Raman spectra measured in the first measurement step and the second measurement step.   The method for manufacturing an electronic component according to claim 1, wherein annealing conditions in the annealing step are adjusted according to the shift amount. An inspection method for an electronic component comprising a sintered body containing a perovskite oxide and an electrode,
A method for inspecting an electronic component comprising a step of measuring a Raman spectrum in a lattice vibration region of the perovskite oxide.   The electronic component inspection method according to claim 3, further comprising: obtaining an oxygen deficiency amount of the perovskite oxide based on a shift amount of the peak of the Raman spectrum.

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