JP5266874B2 - Manufacturing method of ceramic electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic electronic component with an external electrode by forming a conductive resin layer in air, which can solve the problem that an insulating resistance of the ceramic blank significantly decreases because of the penetrated moisture from outside through the conductive resin layer in high-temperature and high-humidity environment. <P>SOLUTION: A conductive paste containing metallic powders and a thermo-setting resin is applied to a surface of a ceramic blank 3 connecting to an inner conductor 2 formed in the ceramic blank 3, and the conductive paste are heat-treated and cured. In the method of manufacturing the ceramic component, a maximum temperature for heat-treatment is set in the vicinity of the carbonization initiation temperature of the thermo-setting resin, the oxygen concentration is set to &ge;10<SP>-4</SP>ppm and &ge;2.5&times;10<SP>2</SP>ppm from the glass-transition temperature to the maximum temperature. Accordingly, the ceramic electronic component has excellent insulating resistance, and it is possible to reduce the degradation in the insulting resistance of the ceramic electronic component in the high-temperature and high-humidity environment. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a ceramic electronic component having an external electrode made of a conductive resin.

  One of the typical ceramic electronic components is a multilayer ceramic capacitor. The multilayer ceramic capacitor includes a ceramic body in which inner conductors and ceramic layers are alternately stacked, and the inner conductor exposed at both ends of the ceramic body. The external electrode is disposed so as to be electrically connected.

  Some external electrodes of ceramic electronic components having such a structure include a conductive resin layer in order to improve mechanical strength such as flexibility and drop impact resistance.

  This conductive resin layer is formed by directly applying a conductive paste, which is a mixture of a metal powder such as silver, and a heat-resistant resin such as an epoxy resin, to a ceramic body and performing a high-temperature heat treatment in the atmosphere. ing.

As prior art document information relating to the invention of this application, for example, the one shown in Patent Document 1 is known.
JP-A-6-267784

  However, in such a conventional method of manufacturing a ceramic electronic component, the conductive resin layer deteriorates during the heat treatment for curing the conductive paste, and moisture penetrates from the outside through the external electrode in a high temperature and high humidity environment to insulate the ceramic body. There was a problem that the resistance was significantly reduced.

  The present invention solves such a conventional problem, and the insulation resistance of the ceramic electronic component is good, and the deterioration of the insulation resistance of the ceramic electronic component due to the intrusion of moisture is reduced, so that the highly reliable ceramic electronic component is manufactured. It is intended to provide a method.

In order to achieve the above object, the present invention provides a method for manufacturing a ceramic electronic component in which an external electrode is provided on a ceramic body having an internal conductor, the external electrode having a conductive resin layer, and the conductive resin In the step of forming a layer, after applying a conductive paste containing a metal powder and a thermosetting resin, the conductive paste is cured by heat treatment, and the oxygen concentration is 10 at least at the highest temperature in the heat treatment. This is a method for producing a ceramic electronic component having a concentration of from ⁻⁴ ppm to 2.5 × 10 ² ppm.

As described above, according to the method for producing a ceramic electronic component of the present invention, the oxygen concentration is 10 ⁻⁴ ppm or more to 2.5 × 10 ² ppm or less at least at the highest temperature in the heat treatment for curing the conductive paste. Thus, a dense conductive resin layer can be formed without impairing the adhesion between the thermosetting resin of the conductive resin layer and the metal powder.

  As a result, the insulation resistance of ceramic electronic parts is excellent, and in high temperature and high humidity environments, moisture can be prevented from entering the ceramic body through external electrodes, and the deterioration of insulation resistance of ceramic electronic parts can be reduced. Can be improved.

(Embodiment)
A multilayer ceramic capacitor will be specifically described as the ceramic electronic component according to the embodiment of the present invention.

  FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.

  As shown in FIG. 1, the multilayer ceramic capacitor is obtained by providing an external electrode 4 on a rectangular ceramic body 3 having an internal conductor 2.

  The ceramic body 3 is formed by alternately laminating ceramic layers 1 and internal conductors 2, and the ceramic layer 1 is composed of ceramic particles of a dielectric material mainly composed of barium titanate, strontium titanate, or the like. The inner conductor 2 contains a metal such as nickel, palladium, or platinum as a main component.

  The protective layer 8 is provided on the ceramic body 3 on the upper and lower sides of the alternately laminated ceramic layers 1 and the internal conductors 2 and is made of ceramic particles and has insulating properties.

  The external electrode 4 is electrically connected to the internal conductor 2 exposed at both ends of the ceramic body 3 and is disposed at both ends of the ceramic body 3. The external electrode 4 is a base electrode 6 provided on the surface of the ceramic body 3. And a metal layer 7 formed on the surface of the base electrode 6.

  The base electrode 6 is a conductive resin layer 5 containing conductive metal powder and a thermosetting resin, and the thickness of the conductive resin layer 5 is preferably 2 μm to 80 μm.

  The metal layer 7 is a plating layer made of nickel, copper, tin or the like formed by plating.

  The base electrode 6 may be formed by forming the conductive resin layer 5 on a conductive fired layer (not shown) provided on the surface of the ceramic body 3, and the conductive fired layer is made of silver, copper, nickel. A conductive paste obtained by mixing a metal powder such as glass frit with an organic vehicle is applied onto the ceramic body 3 and fired at a temperature of 600 ° C to 800 ° C.

  Next, a method for manufacturing the conductive resin layer 5 of the external electrode 4 will be described.

  The conductive resin layer 5 is manufactured by applying a conductive paste to the end of the ceramic body 3 by dip coating, printing, transfer, etc., and then curing the conductive paste by heat treatment to form the conductive resin layer 5. To form.

  The conductive paste used for forming the conductive resin layer 5 is a mixture of metal powder, binder resin, curing accelerator, solvent, and the like.

  The metal powder of the conductive paste can be selected from conductive powders of noble metals such as silver and palladium, conductive powders of base metals such as nickel and copper, and conductive powders of alloys of these metals.

  Further, the metal powder preferably contains a low melting point metal, the melting point of the low melting point metal is 130 ° C. or higher and the maximum temperature Tm of the heat treatment of the conductive paste, and the low melting point metal is tin or tin and silver. Further, a metal such as a tin alloy to which copper, zinc, bismuth or the like is added can be used.

  By including a low melting point metal in the conductive paste, a diffusion reaction between the low melting point metal and the metal contained in the internal conductor 2 is likely to occur during the heat treatment for forming the conductive resin layer 5. The electrical bondability between the layer 5 and the inner conductor 2 can be improved.

  The binder resin of the conductive paste contains a thermosetting resin as a main component, and the thermosetting resin is a bisphenol A type, bisphenol F type, phenol novolac type epoxy resin, or a resol type or novolac type phenol. Preferably, the thermosetting resin is selected from a resin, a silicone-modified resin, and the like, and the temperature at which the thermosetting resin starts to be carbonized is 300 ° C. or higher from the usage conditions of the multilayer ceramic capacitor.

  The solvent of the conductive paste is selected depending on the metal powder of the conductive paste, the type and content of the resin, the coating method, and the like.

  Here, the temperature at which the thermosetting resin starts to carbonize is the temperature at which the carbons constituting the skeleton of the thermosetting resin or the functional group attached to the skeleton starts to break.

  The temperature at which carbonization starts is carried out as follows in the case of thermogravimetry.

  First, the conductive paste is dried in an air atmosphere at a temperature of 150 ° C. for 60 minutes, and the solvent contained in the conductive paste is volatilized to obtain a solidified conductive paste.

  Next, the solidified conductive paste is heated at a temperature of 10 ± 1 ° C. per minute from room temperature by flowing a gas in an oxygen concentration atmosphere set at the maximum temperature Tm of heat treatment described later, and solidified. The mass change rate of the conductive paste is measured as a function of temperature and a TG curve is drawn.

  FIG. 3 is a TG curve of thermogravimetry of the conductive paste in the embodiment of the present invention.

  As shown in FIG. 3, the vertical axis represents the rate of mass change based on room temperature of the solidified conductive paste, and the horizontal axis represents the temperature.

  The temperature at the inflection point of the TG curve is defined as a contact a of a tangent A having a maximum tangent slope, a contact b of a tangent B having a minimum value, and a contact b of a tangent B having a minimum value. A temperature corresponding to the intersection of A and tangent line B.

  Subsequently, the temperature at which carbonization starts is calculated from the TG curve.

  The temperature at which carbonization starts is the temperature at the bending point where the temperature is 250 ° C. or higher, and is the temperature Tc corresponding to the intersection point where the tangent line A on the low temperature side and the tangent line B on the high temperature side intersect. Furthermore, the gradient of the tangent of the temperature at which carbonization starts is a value of −0.010 wt% / ° C. or less. When there are a plurality of bending points that satisfy this condition, the lowest temperature is the temperature at which carbonization starts.

  FIG. 2 is a diagram showing the time and temperature of heat treatment for curing the conductive paste and the oxygen concentration in the embodiment of the present invention.

  As shown in FIG. 2, the temperature pattern in the heat treatment for curing the conductive paste is such that the temperature is increased from room temperature to the maximum temperature Tm with a predetermined rising temperature per hour, and when the temperature reaches the maximum temperature Tm, the maximum temperature is reached. The conductive paste is cured by holding at Tm for a certain period of time.

  Thereafter, the temperature is lowered and cooled from the maximum temperature Tm to a normal temperature with a predetermined lowering temperature per hour.

  The temperature gradient of the temperature rise is adjusted as appropriate in order to control the progress of the curing reaction of the conductive paste.

The oxygen concentration pattern in the heat treatment of the conductive paste decreases the oxygen concentration in an inert gas such as argon or nitrogen as the temperature rises, and the oxygen concentration at least at the maximum temperature Tm is 10 ⁻⁴ ppm or more to 2.5 ×. It shall be in the range of 10 ² ppm or less. Further, the oxygen concentration is increased as the temperature falls.

When the oxygen concentration at the maximum temperature Tm is higher than 2.5 × 10 ² ppm, the thermosetting resin is oxidized and deteriorated, and the adhesion between the metal powder contained in the conductive resin layer 5 and the thermosetting resin is deteriorated. The denseness of the conductive resin layer 5 decreases, and moisture easily enters the ceramic body 3 through the external electrode in a high temperature and high humidity environment, and the insulation resistance of the multilayer ceramic capacitor decreases.

When the oxygen concentration at the maximum temperature Tm is smaller than 10 ⁻⁴ ppm, the reduction reaction of the ceramic layer 1 occurs, and the initial insulation resistance of the multilayer ceramic capacitor is lowered.

  The maximum temperature Tm for the heat treatment of the conductive paste is not less than the glass transition temperature Tg of the thermosetting resin and not more than the vicinity of the temperature at which the thermosetting resin starts to be carbonized.

  When the thermosetting resin of the conductive paste is mainly composed of a mixture of an epoxy resin and a phenolic resin as a curing agent, the glass transition temperature of the thermosetting resin is 150 ° C. to 250 ° C., and carbonization starts Has a temperature of 300 ° C. to 450 ° C.

  By setting the maximum heat treatment temperature Tm to the glass transition temperature or higher, the structure of the thermosetting resin of the conductive resin layer 5 can be stabilized, and the adhesion strength between the conductive resin layer 5 and the internal conductor 2 is improved. The electrical connection between the conductive resin layer 5 and the internal conductor 2 can be ensured in a high temperature environment such as a reflow temperature when mounted on a printed circuit board.

  The maximum temperature Tm for the heat treatment is preferably in the vicinity of the temperature at which the thermosetting resin of the conductive resin layer 5 starts to be carbonized, thereby maintaining the denseness of the conductive resin layer 5 and the conductive resin layer 5. Metal diffusion between the metal powder and the metal of the inner conductor 2 is likely to occur, and the electrical connection between the conductive resin layer 5 and the inner conductor 2 can be ensured, and deterioration of insulation resistance in a high temperature and high humidity environment can be reduced. In addition, variation in capacitance can be reduced.

  More specifically, the vicinity of the temperature at which the thermosetting resin starts to carbonize is a temperature range from 30 ° C. to 20 ° C. higher than the temperature at which carbonization starts.

Further, the temperature at which the oxygen concentration is 10 ⁻⁴ ppm or more and 2.5 × 10 ² ppm or less is at least the temperature below the glass transition temperature of the thermosetting resin of the conductive resin layer 5 and the maximum temperature Tm. Preferably, this makes it easier for the thermosetting resin to undergo oxidative deterioration during heat treatment, and increases the effect of preventing moisture from entering the ceramic body 3 in a high-temperature and high-humidity environment. Even in the environment, deterioration of insulation resistance of the multilayer ceramic capacitor can be reduced, and reliability can be improved.

  In addition, it is more preferable that the oxygen concentration in the embodiment of the present invention is set from the maximum temperature Tm to at least the glass transition temperature of the thermosetting resin even in the temperature drop during the heat treatment of the conductive paste.

  Specific examples will be described below.

Example 1
In the multilayer ceramic capacitor of Example 1, the ceramic body is obtained by alternately laminating ceramic layers mainly composed of barium titanate and internal conductors mainly composed of nickel, and external electrodes are formed at both ends of the ceramic body. Formed of a conductive resin layer and a metal layer.

  First, a ceramic slurry and a nickel metal paste are prepared.

  The ceramic slurry is obtained by dispersing ceramic powder in an organic vehicle whose main component is polyvinyl butyral, and the ceramic powder is a dielectric powder of barium titanate whose main particle size is 0.1 to 1.0 μm. In addition, 0.1 to 5 wt% of a trace amount additive such as a manganese compound, silica, or an oxide of a rare earth element is added.

  The nickel metal paste is a mixture of a metal powder mainly composed of nickel, an acrylic organic binder, a solvent, a plasticizer, and the like. The metal powder has an average particle size of 0.01 to 2 μm and is 20% in the nickel metal paste. -70 wt% is contained.

  Next, the ceramic slurry was applied on the substrate and dried to form a green sheet having a thickness of 1 to 3 μm.

  Further, a nickel metal paste was printed on the green sheet by screen printing to form an internal conductor having a thickness of 1 to 2 μm, and a green sheet provided with the internal conductor was formed.

  Subsequently, a plurality of protective layer sheets made of the green sheets are laminated and pressure-bonded, and 160 green sheets provided with the internal conductors are laminated and pressure-bonded thereon, and a plurality of the protective layer sheets are further formed on the sheets. Lamination and pressure bonding were performed to form a laminate.

  Next, this laminate was cut into individual pieces, and then fired in a reducing atmosphere at 1100 to 1300 ° C. to obtain a ceramic body.

  Further, a conductive resin layer of the external electrode is formed on the surface of the ceramic body.

  For forming the conductive resin layer, first, a conductive paste for the conductive resin layer is applied to the substrate and scraped off with a blade to form a thin film of the conductive paste having a certain thickness. Next, the end of the ceramic body was immersed in the thin film, and a conductive paste was applied to both ends of the ceramic body. Further, the conductive paste was cured by heat treatment to form a conductive resin layer.

  The conductive paste for the conductive resin layer contains metal powder and a thermosetting resin.

  The metal powder of the conductive paste is a mixture of silver powder having an average particle diameter of 1 to 10 μm and tin powder having an average particle diameter of 1 to 10 μm, and the metal powder is contained in the conductive paste in an amount of 60 wt% to 90 wt%.

  The thermosetting resin of the conductive paste is a mixture of a bisphenol A type epoxy resin and a resol type phenol resin of a curing agent, and the thermosetting resin is contained in the conductive paste in an amount of 5 wt% to 40 wt%.

This conductive paste has a temperature at which carbonization of the thermosetting resin starts at 330 ° C. and a glass transition temperature of 210 ° C. when nitrogen gas having an oxygen concentration of 8.0 × 10 ⁻¹ ppm is flowed in and measured by thermogravimetry. It is.

  The temperature pattern of the heat treatment is that the maximum temperature is 330 ° C., the temperature at which carbonization starts, and after the temperature is raised from room temperature to the maximum temperature with a temperature gradient of 7 ° C. to 60 ° C. per minute, the maximum temperature is held for 10 minutes to 60 minutes. The temperature is lowered to room temperature with a temperature gradient of 7 ° C. to 60 ° C. per minute and cooled.

  The oxygen concentration in the heat treatment was controlled by adjusting the injection amounts of nitrogen gas and oxygen gas during temperature rise and fall from room temperature.

The oxygen concentration pattern at the time of temperature increase in the heat treatment is decreased exponentially from the atmospheric atmosphere at room temperature, the oxygen concentration is 210 × 10 ⁴ ppm at 210 ° C., 2.5 × 10 ² ppm at 270 ° C., 330 It was made to be 8.0 × 10 ⁻¹ ppm at a temperature.

  The oxygen concentration pattern when the temperature of the heat treatment was lowered was set so that the oxygen concentration with respect to the temperature of the heat treatment was the same as when the temperature was raised.

  Next, electrolytic plating of nickel and tin was sequentially performed to form a metal layer on the conductive resin layer, an external electrode was provided, and a 6.3 V 1 μF multilayer ceramic capacitor was fabricated.

(Example 2 to Example 5)
Examples 2 to 5 were produced in the same manner as Example 1 except that the oxygen concentration pattern of the heat treatment of the conductive paste was different from Example 1.

  The maximum temperature of the heat treatment is 330 ° C., which is the same as in Example 1.

  In Examples 2 to 5, the oxygen concentration pattern was the same as that in Example 1 until the temperature was raised to 270 ° C., and the oxygen concentration pattern was made different at temperatures higher than 270 ° C.

The oxygen concentration of Example 2 was kept constant at 2.5 × 10 ² ppm at a temperature higher than 270 ° C.

In Example 3, the oxygen concentration was gradually decreased at a temperature higher than 270 ° C., and was set to 1.0 × 10 ² ppm at 330 ° C. Examples 4 and 5 were set to 2.1 × 10 ⁻³ ppm and 1.0 × 10 ⁻⁴ ppm at 330 ° C., respectively.

(Example 6, Example 7)
Example 6 and Example 7 were produced in the same manner as Example 1 except that the temperature pattern and oxygen concentration pattern of the heat treatment of the conductive paste were different from Example 1.

  In the temperature pattern of the heat treatment of Example 6 and Example 7, the maximum temperature is 270 ° C. lower than that of Example 1, and after the temperature is increased from room temperature to the maximum temperature with a temperature gradient of 3 ° C. to 60 ° C. per minute, the maximum temperature Is kept for 60 minutes to 180 minutes, cooled to room temperature with a temperature gradient of 3 ° C. to 60 ° C. per minute, and cooled.

In Example 6, the oxygen concentration pattern was exponentially reduced from the ambient air atmosphere at room temperature to 2.5 × 10 ² ppm at 210 ° C. and 1.0 × 10 ⁻⁴ ppm at 270 ° C. In Example 7, 1.0 × 10 ⁴ ppm at 210 ° C. and 2.5 × 10 ² ppm at 270 ° C. were set.

(Comparative Examples 1 to 5)
Comparative Example 1 and Comparative Example 2 were produced in the same manner as Example 6 except that Example 6 and the oxygen concentration pattern in the heat treatment of the conductive paste were different.

The oxygen concentration patterns of Comparative Example 1 and Comparative Example 2 are the same as those of Example 6 from room temperature to 210 ° C., and are 2.5 × 10 ² ppm at 210 ° C., and Comparative Example 1 is 4 × 10 ⁻⁶ at 270 ° C. ppm and Comparative Example 2 were set to 3.0 × 10 ⁻⁵ ppm.

  Comparative Examples 3 to 5 were produced in the same manner as Example 7 except that Example 7 and the oxygen concentration pattern in the heat treatment of the conductive paste were different.

The oxygen concentration patterns of Comparative Example 3 and Comparative Example 4 are the same as those of Example 7 from room temperature to 210 ° C., and are set to 1.0 × 10 ⁴ ppm at 210 ° C., and Comparative Example 3 is 5.0 × at 270 ° C. 10 ² ppm and Comparative Example 4 were set to 1.0 × 10 ³ ppm. In Comparative Example 5, heat treatment was performed in an air atmosphere.

  Next, 300 samples were measured for each of the multilayer ceramic capacitors of Examples 1 to 7 and Comparative Examples 1 to 5, and the average value of the initial insulation resistance values was calculated.

Further, those having an initial insulation resistance value of 1.0 × 10 ⁸ Ω or more were selected, and a high-temperature and high-humidity load test with a temperature of 85 ° C. and a humidity of 85% and a rated voltage of 6.3 V applied to 500 samples was performed. After a period of time, an insulation resistance value after the test of less than 5.0 × 10 ⁶ Ω was regarded as abnormal, and the failure rate of the insulation resistance value was calculated.

  The results are shown in Table 1.

As shown in Table 1, Examples 1 to 7, the initial insulation resistance value was ^{1.8 × 10 9 Ω~2.2 × 10 9} Ω, failure rate of the high-temperature high-humidity load test Was 0.0%, which was good.

On the other hand, Comparative Example 1 and Comparative Example 2 have initial insulation resistance values of 6.4 × 10 ⁷ Ω and 7.9 × 10 ⁸ Ω, respectively, which are lower than those of Examples 1 to 7. As described above, when the oxygen concentration is lower than 1.0 × 10 ⁻⁴ ppm at the maximum temperature in the heat treatment for curing the conductive paste, the initial insulation resistance of the multilayer ceramic capacitor is deteriorated. The resistance is getting worse.

In Comparative Examples 3 to 5, the failure rate of the high-temperature and high-humidity load test is 3.0%, 8.4%, and 25.0%, respectively, which are larger than those of Examples 1 to 7. Yes. Thus, when the oxygen concentration is higher than 2.5 × 10 ² ppm at the maximum temperature in the heat treatment for curing the conductive paste, the failure rate of the high-temperature and high-humidity load test increases, and the failure rate increases as the oxygen concentration increases. It is getting worse.

As described above, when the oxygen concentration is 10 ⁻⁴ ppm or more and 2.5 × 10 ² ppm or less at the highest temperature in the heat treatment for curing the conductive paste, the initial insulation resistance of the multilayer ceramic capacitor is high, In addition, it is possible to reduce the occurrence of defects in insulation resistance in the high temperature and high humidity load test.

(Example 8)
Example 8 was produced in the same manner as in Example 1 except that the oxygen concentration pattern of the heat treatment of the conductive paste was different from that in Example 1.

  The temperature pattern of the heat treatment in Example 8 is the same as that in Example 1, and the maximum temperature is 330 ° C.

The oxygen concentration pattern at the time of temperature increase in the heat treatment is decreased exponentially from a normal temperature air atmosphere to 8.0 × 10 ⁻¹ ppm at 210 ° C., and at a temperature higher than this, the oxygen concentration is 8.0. The constant was set to × 10 ^-1 ppm.

  Next, as in Example 1, a high temperature and high humidity load test with a temperature of 85 ° C., a humidity of 85%, and a rated voltage of 6.3 V was performed for Example 8 for 1000 hours. Furthermore, about Example 1 and Example 8, the test time of the high-temperature, high-humidity load test was 2000 hours, and the defect rate of the insulation resistance value was calculated.

  The results are shown in Table 2.

  As shown in Table 2, in Example 1 and Example 8, the failure rates after 2000 hours of the high temperature and high humidity load test were 0.3% and 0.0%, respectively.

In Example 1 and Example 8, the oxygen concentration at the maximum temperature of the heat treatment is the same at 8.0 × 10 ⁻¹ ppm, but in Example 8, the oxygen concentration is 8.0 × 10 ⁻¹ ppm. The temperature is in the range from the glass transition temperature to the maximum temperature, which makes it difficult for the insulation resistance deterioration in the high temperature and high humidity load test to occur for a long time.

(Example 9 to Example 12)
Examples 9 to 12 were produced in the same manner as in Example 1 except that the temperature pattern and oxygen concentration pattern of the heat treatment of the conductive paste were different from those in Example 1.

The maximum temperatures of Examples 9 to 12 are 300 ° C., 330 ° C., 350 ° C., and 270 ° C., respectively, and the oxygen concentration at the maximum temperature is 8.0 × 10 ⁻¹ ppm, which is the same as that of Example 1.

  The temperature pattern of the heat treatment is that the temperature is raised from room temperature to a maximum temperature with a temperature gradient of 7 ° C. to 60 ° C. per minute, then the maximum temperature is maintained for 10 minutes to 60 minutes, and the temperature gradient of 7 ° C. to 60 ° C. per minute The temperature is lowered and cooled.

Oxygen concentration pattern, Examples 9 11, 1.0 × 10 ⁴ ppm at 210 ° C. from the atmosphere at normal temperature, 270 ° C. at 2.5 × 10 ² ppm, 300 ℃ at 8.0 × 10 ^{- 1} ppm, and kept constant at 8.0 × 10 ⁻¹ ppm above 300 ° C.

In Example 12, it was 2.5 × 10 ² ppm at 210 ° C. and 8.0 × 10 ⁻¹ ppm at 270 ° C.

In all of Examples 9 to 12, the average value of the initial insulation resistance value is 1.9 × 10 ⁹ Ω or more, and the temperature and humidity are 85 ° C., humidity 85%, and rated voltage 6.3 V applied. The failure rate of 1000 hours in the load test was good at 0.0%.

  Next, with respect to 500 samples of each of Examples 9 to 12 and Comparative Example 6, the initial capacitance was measured, and the variation in capacitance was calculated. The variation in capacitance is obtained by dividing the standard deviation value σ of capacitance by the average value of capacitance.

  The results are shown in Table 3.

  As shown in Table 3, the variations in the capacitances of Examples 9 to 12 and Comparative Example 6 were 0.019, 0.012, 0.011, 0.055, and 0.056, respectively.

  The maximum temperature of the heat treatment is 270 ° C. in Example 12 and Comparative Example 6, whereas in Examples 9 to 11, the temperature is 300 ° C. to 350 ° C. near the temperature at which carbonization starts. By setting the maximum temperature near the temperature at which carbonization starts, it is possible to improve the electrical connection between each layer of the inner conductor and the conductive resin layer while reducing the insulation resistance deterioration in the high temperature and high humidity load test. The variation can be reduced.

  According to the method for manufacturing a ceramic electronic component according to the present invention, the adhesiveness between the thermosetting resin of the conductive resin layer and the metal powder is not impaired during the heat treatment for curing the conductive paste. Since the component has excellent insulation resistance and high reliability, it is extremely useful in various electronic devices and electric circuits.

Sectional drawing of the multilayer ceramic capacitor in embodiment of this invention The figure which shows the time and temperature of heat processing which harden the electrically conductive paste in embodiment of this invention, and oxygen concentration The figure which shows the TG curve of the thermogravimetry of the electrically conductive paste in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic layer 2 Internal conductor 3 Ceramic body 4 External electrode 5 Conductive resin layer 6 Base electrode 7 Metal layer 8 Protective layer

Claims (2)

A method of manufacturing a ceramic electronic component in which an external electrode is provided on a ceramic body having an internal conductor, wherein the external electrode has a conductive resin layer, and the step of forming the conductive resin layer includes metal powder and thermosetting After applying a conductive paste containing a conductive resin, the conductive paste is cured by heat treatment, and the oxygen concentration is 10 ⁻⁴ ppm or more to 2.5 × 10 ² at least at the highest temperature in the heat treatment. The method for producing a ceramic electronic component , wherein the maximum temperature is not more than ppm and the maximum temperature is in the vicinity of a temperature at which the thermosetting resin starts to be carbonized . ^2. The production of a ceramic electronic component according to claim 1, wherein the temperature at which the oxygen concentration is 10 ⁻⁴ ppm or more and 2.5 × 10 ² ppm or less is at least the glass transition temperature of the thermosetting resin to the maximum temperature. Method.

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