KR20120075347A - Dielectric ceramic composition and electronic component - Google Patents

Abstract

PURPOSE: A zinc oxide nanostructure density control method using seed layer and electronic components using the same are provided to facilitate large are growth by controlling density of a structure which is grown up by using concentration and particle size of the impurities. CONSTITUTION: A zinc oxide nanostructure density control method using seed layer comprises the following step of forming zinc oxide seed layer and growing zinc oxide nanostructure using the seed layer. The formation method of the zinc oxide seed layer comprises the following steps: dispersing impurity particles in a zinc oxide precursor solution; spreading the dispersed mixture on a substrate with a spin coating; and heat treating the substrate. In the dispersion step, a dispersing agent or stabilizer is used. In the dispersion step, the impurity particles are different kind metal oxide including TiO2 or Al2O3, etc. Concentration and particle size of the impurities are controlled. The heat treating step is processed at 200-500 deg. Celsius. An electronic component using zinc oxide nanostructure density control method comprises a ceramic condenser(2), a protective resin(4), lead terminals(6,8), a dielectric layer(10), and terminal electrodes(12,14).

Description

Dielectric Ceramic Composition and Electronic Component {DIELECTRIC CERAMIC COMPOSITION AND ELECTRONIC COMPONENT}

TECHNICAL FIELD The present invention relates to dielectric ceramic compositions and electronic components.

In recent years, the miniaturization and complexity of electrical circuits are rapidly progressing along with the rapid progress of high performance electrical equipment. For this reason, further miniaturization and high performance are required for electronic components. That is, a dielectric ceramic composition and an electronic component having a high dielectric constant and a high alternating current breakdown voltage are required to maintain the electrostatic capacity even though miniaturization while maintaining good temperature characteristics.

Conventionally, as high-k dielectric ceramic compositions widely used as magnetic capacitors, multilayer capacitors, high frequency capacitors, high voltage capacitors, and the like, as in Patent Documents 1 to 4 It is known that a main component is a magnetic composition of BaTiO ₃ , BaZr0 ₃ , CaTi0 ₃ , SrTi0 ₃ system.

However, such conventional BaTi0 ₃ , BaZr0 ₃ , CaTi0 ₃ , and SrTi0 ₃ magnetic compositions are ferroelectric, and therefore, it is difficult to secure a high AC breakdown voltage while maintaining high capacitance and low dielectric loss.

Patent Document 1: Japanese Unexamined Patent Publication No. 1994-302219 Patent Document 2: Japanese Patent Laid-Open No. 2003-104774 Patent Document 3: Japanese Unexamined Patent Publication No. 2003-109430 Patent document 4; Japanese Patent Publication No. 2004-238251

This invention is made | formed in view of such a situation, and the objective is to provide the dielectric ceramic composition with high dielectric constant and alternating current breakdown voltage, low dielectric loss, and favorable temperature characteristic and sinterability. It is another object of the present invention to provide an electronic component having a dielectric layer composed of such a dielectric ceramic composition.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to achieve the said objective, the present inventors discovered that the said objective can be achieved by making a composition of a dielectric ceramic composition into a specific component, and making these ratio into a predetermined range, and to complete this invention, Reached.

That is, the dielectric ceramic composition according to the present invention to solve the above problems, the main component represented by the composition formula of (Ba _{1- xy} , Ca _x , Sr _y ) _m (Ti _{1 -za} , Zr _z , Sn _a ) O ₃ , A dielectric ceramic composition having a first subcomponent and a second subcomponent,

X in said composition formula is 0.03≤x≤0.30,

Y in the said composition formula is 0.00 <y≤0.05,

Z in the said composition formula is 0.02 <z <= 0.2,

A in said composition formula is O≤a≤0.2,

Z + a in the said composition formula is 0.04 <= z + a <= 0.3,

M in the said composition formula is 0.97 <= m <= 1.03,

The first accessory ingredient is zinc oxide,

The second accessory ingredient is at least one oxide selected from La, Pr, Pm, Nd, Sm, Eu, Gd and Y,

0.45-10 weight% of the said 1st subcomponent is contained with respect to 100 weight% of said main components,

The second accessory ingredient is a dielectric ceramic composition containing more than 0.0% by weight and 0.3% by weight or less in terms of oxide with respect to 100% by weight of the main component.

According to the present invention, it is possible to provide a dielectric ceramic composition having high dielectric constant and alternating current breakdown voltage, low dielectric loss, and good temperature characteristics and sinterability.

An electronic component according to an embodiment of the present invention has a dielectric layer composed of the dielectric ceramic composition.

The electronic component according to the embodiment of the present invention is not particularly limited, but may be a single plate type ceramic capacitor, a through type capacitor, a multilayer ceramic capacitor, a piezoelectric element, a chip inductor, a chip varistor, a chip thermistor, a chip resistor, Other surface mount (SMD) chip electronic components are illustrated.

FIG. 1A is a front view of a ceramic capacitor according to an embodiment of the present invention, and FIG. 1B is a side cross-sectional view of the ceramic capacitor according to an embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on embodiment shown in drawing.

Ceramic Capacitors (2)

As shown in FIG. 1A, the ceramic capacitor 2 according to the embodiment of the present invention includes a dielectric layer 10, a pair of terminal electrodes 12 and 14 formed on an opposite surface thereof, and the terminal. It has the structure which has the lead terminals 6 and 8 connected to the electrodes 12 and 14, respectively, These are covered with the protective resin 4. As shown in FIG. Although the shape of the ceramic capacitor | condenser 2 may be suitably determined according to an objective and a use, it is preferable that it is a disc shaped capacitor | condenser in which the dielectric layer 10 becomes a disk shape. Moreover, what is necessary is just to determine the dimension suitably according to an objective and a use, Usually, about 3-20 mm in diameter, Preferably it is about 3-15 mm.

Although the thickness of the dielectric layer 10 is not specifically limited, What is necessary is just to determine suitably according to a use etc., Preferably it is 0.3-2 mm. By setting the thickness of the dielectric layer 10 to such a range, it can use suitably for a high pressure application.

The terminal electrodes 12 and 14 are made of a conductive material. As a electrically conductive material used for the terminal electrodes 12 and 14, Cu, Cu alloy, Ag, Ag alloy, In-Ga alloy etc. are mentioned, for example.

Dielectric layer 10

The dielectric layer 10 of the ceramic capacitor 2 is made of a dielectric ceramic composition according to the embodiment of the present invention.

The dielectric ceramic composition according to the embodiment of the present invention includes a main component, a first subcomponent represented by a composition formula of (Ba _{1 -xy} , Ca _x , Sr _y ) _m (Ti _{1 -za} , Zr _z , Sn _a ) O ₃ and A dielectric ceramic composition having a second subcomponent.

In the above composition formula, x represents the ratio of Ca and the range is 0.03 ≦ x ≦ 0.30. By containing Ca in this range, the dielectric constant, alternating current breakdown voltage, and sinterability are improved, and the temperature characteristics tend to be good. From this point of view, x is preferably 0.08 ≦ x ≦ 0.16.

Y in the said composition formula represents the ratio of Sr, and the range is 0.00 <y <0.05. By containing Sr in this range, the dielectric constant improves and the temperature characteristic of both the low temperature side and the high temperature side tends to be good. From this point of view, y is preferably 0.006 ≦ y ≦ 0.02.

Z in the said composition formula represents the ratio of Zr, and the range is 0.02 <z <0.2. By containing Zr in this range, the dielectric constant and the alternating current breakdown voltage are improved, the dielectric loss is decreased, and the temperature characteristics of both the low temperature side and the high temperature side tend to be good. From this point of view, z is preferably 0.06 ≦ z ≦ 0.15.

A in the said composition formula shows the ratio of Sn, and the range is 0 <= a <= 0.2. By containing Sn in this range, relative dielectric constant and alternating current breakdown voltage improve and it becomes the tendency for temperature characteristics to become favorable. From this point of view, a is preferably 0 ≦ a ≦ 0.15.

Z + a in the said composition formula represents the total ratio of Zr and Sn, and the range is 0.04 <= z + a <= 0.3. By containing Sn in this range, the dielectric constant and the alternating current breakdown voltage are improved, the dielectric loss is decreased, and the temperature characteristics tend to be good. From this point of view, z + a is preferably 0.06 ≦ z + a ≦ 0.2.

M in the said composition formula shows the molar ratio of Ba, Ca, Sr which are components of A site, and Ti, Zr, Sn which are B site components, and the range is 0.97 <= m <= 1.03. By setting m to this range, the dielectric constant, alternating current breakdown voltage, and sinterability tend to be improved. From this point of view, m is preferably 0.97 ≦ m <1.00.

The first accessory ingredient is zinc oxide. In the dielectric ceramic composition according to the embodiment of the present invention, the first subcomponent contains 0.45 to 10 wt% with respect to 100 wt% of the main component. By making content of a 1st subcomponent into this range, a dielectric constant, alternating current breakdown voltage, and sinterability will improve, and it will become the tendency for temperature characteristics to become favorable. From such a viewpoint, content of a 1st subcomponent becomes like this. Preferably it is 0.8-6 weight%.

The second subcomponent is at least one oxide selected from La, Pr, Pm, Nd, Sm, Eu, Gd and Y, preferably at least one selected from La, Pm, Nd, Sm, Gd and Y. Is an oxide of. The dielectric ceramic composition according to the embodiment of the present invention contains more than 0.0 wt% and less than 0.3 wt% of the second accessory ingredient with respect to 100 wt% of the main component. By making content of a 2nd subcomponent into this range, alternating current breakdown voltage will improve and it will become the tendency for a temperature characteristic to become favorable. In addition, the dielectric ceramic composition according to the embodiment of the present invention has a predetermined composition and an amount of the main component, and has a predetermined amount of the first subcomponent, thereby improving the AC breakdown voltage even if the content of the second subcomponent is relatively small. The temperature characteristic can be made favorable. From such a viewpoint, content of a 2nd subcomponent becomes like this. Preferably it is 0.01 weight% or more and 0.09 weight% or less.

Manufacturing Method of Ceramic Capacitor 2

Next, the manufacturing method of the ceramic capacitor 2 is demonstrated.

First, the dielectric ceramic composition powder which forms the dielectric layer 10 shown in FIG. 1 after baking is manufactured.

Prepare the raw material of the main ingredient and the raw material of each sub ingredient. As the materials of the main component, Ba, Ca, Sr, Ti, Zr, materials which become oxides by the oxides and / or firing of the Sn or, and the like of these composite oxides, such as barium carbonate (BaCO ₃₎ , Calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium dioxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), tin oxide (SnO ₂ ), and the like. In addition, it is also possible to use various compounds which become oxides or a titanium compound after baking, such as a hydroxide, for example. In this case, it is preferable to change content suitably so that the number of elements of a metal element may match.

In addition, although the raw material of a main component may be manufactured by the solid-phase method, and may be manufactured by liquid phase methods, such as a hydrothermal synthesis method and an oxalate method, in terms of manufacturing cost, it is by the solid-phase method. It is preferable to prepare.

It does not specifically limit as a raw material of a 1st subcomponent and a 2nd subcomponent, It can select from a variety of compounds which become said oxide by baking, for example, carbonate, nitrate, hydroxide, an organometallic compound, etc. suitably.

As a method for producing a dielectric ceramic composition according to an embodiment of the present invention, first, a raw material of a main component or a raw material of a main component and a raw material of each subcomponent are blended and wet-mixed using a ball mill made of zirconia balls or the like. When mix | blending a 1st subcomponent at this time, you may mix | blend a 1st subcomponent so that it may become the composition of the dielectric ceramic composition mentioned above, and may mix | blend only a part and may add the remaining 1st subcomponent after plasticization.

A plastic powder can be obtained by granulating the obtained mixture and plasticizing the obtained molded product in an air atmosphere. As the plasticity conditions, for example, the plasticity temperature is preferably 1000 to 1300 ° C, more preferably 1150 to 1250 ° C, and the plasticity time is preferably 0.5 to 4 hours. The raw material of the main component and the raw material of the subcomponent may be calcined, respectively, and then mixed to form a dielectric ceramic composition powder.

Next, the obtained plastic powder is coarsely pulverized. In the case where only a part of the first subcomponent is blended, the remaining first subcomponent is added here so as to be the composition of the dielectric ceramic composition described above in combination with the raw material of the first subcomponent added before plasticity.

The plastic powder or the plastic powder and the raw material of the subcomponent are wet-pulverized by a ball mill or the like, mixed and dried to obtain a dielectric ceramic composition powder. As described above, by producing the dielectric ceramic composition powder by the solid phase method, it is possible to reduce the manufacturing cost while realizing desired characteristics.

Subsequently, an appropriate amount of a binder is added to the obtained dielectric ceramic composition powder, and the granulated product obtained by granulation is compression molded into a disc having a predetermined size to obtain a green molded body. Then, by firing the obtained green molded body, a sintered body of the dielectric ceramic composition is obtained. On the other hand, as baking conditions, although it does not specifically limit, Preferably holding temperature is 1200-1400 degreeC, More preferably, it is 1280-1360 degreeC, It is preferable to make baking atmosphere into air.

Terminal electrodes 12 and 14 are formed by printing a terminal electrode on the main surface of the obtained sintered body of the dielectric ceramic composition and firing as necessary. Thereafter, the lead terminals 6 and 8 are bonded to the terminal electrodes 12 and 14 by soldering or the like, and finally, the element body is covered with the protective resin 4 to thereby cover the parts of FIGS. 1A and 1. A single plate ceramic capacitor as shown in (B) is obtained.

The ceramic capacitor of the present invention manufactured in this manner is mounted on a printed board or the like via the lead terminals 6 and 8 and used for various electronic devices.

As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, Of course, it can change in various ways within the range which does not deviate from the summary of this invention.

Although the above-described embodiment exemplifies a single plate ceramic capacitor having a single dielectric layer as the electronic component according to the present invention, it is not limited to the single plate ceramic capacitor as the electronic component according to the present invention, and the dielectric paste contains the above dielectric ceramic composition. And a multilayer ceramic capacitor produced by an ordinary printing method or sheet method using an electrode paste, or the dielectric layer of the through capacitor may be produced using the above dielectric ceramic composition.

<Examples>

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

Sample 1 to 58

BaCO ₃ , CaCO ₃ , SrCO ₃ , TiO ₂ , ZrO ₂ and SnO ₂ were prepared as raw materials of the main components. In addition, Zn0 ₂ as a raw material of the first subcomponent, La ₂ O ₃ , Pr ₆ O ₁₁ , Pm ₂ O ₃ , Nd ₂ O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O as raw materials of the second subcomponent. ₃ and Y ₂ O ₃ were prepared, respectively. And these prepared raw materials were weighed so that it might become the composition shown to the samples 1-58 of Table 1 and Table 2. This raw material blend was subjected to wet mixing and agitation for 3 hours using a ball mill, and dehydrated and dried, then calcined at 1170 to 1210 ° C to cause a chemical reaction.

Subsequently, after coarsely pulverizing this, it grind | pulverizes with a pot mill again to about 0.5-2 micrometers, and after dehydrating and drying, polyvinyl alcohol (PVA) is added to this as an organic binder, and granulation granulation is carried out. To granule powder. This granulated powder was molded at a pressure of 300 MPa to form a disc shaped molded article having a diameter of 16.5 mm and a thickness of 1.15 mm.

The obtained molded object was fired at around 1350 ° C. in air to obtain a magnetic body. Thus, the baking electrode was formed in the silver (Ag) paste on both surfaces of the obtained magnetic body, the lead wire was soldered to this, and the magnetic capacitor was obtained. Table 3 shows the results of measuring the relative dielectric constant, dielectric loss, alternating current breakdown voltage, temperature characteristics, and sinterability of the sample thus obtained.

(Dielectric constant (ε))

The relative dielectric constant ε was calculated from the capacitance measured under a condition of a frequency of 1 kHz and an input signal level (measured voltage) of 1.0 Vrms using a digital LCR meter (4274A manufactured by Agilent Technologies) at a reference temperature of 20 ° C for a capacitor sample. No units). The higher the dielectric constant, the better. In this example, 8000 or more was satisfactory.

(Dielectric loss (tanδ))

The dielectric loss (tanδ) was measured on a capacitor sample under a condition of a frequency of 1 kHz and an input signal level (measured voltage) of 1.0 Vrms using a digital LCR meter (4274A manufactured by Agilent Technologies) at a reference temperature of 20 ° C. The lower the dielectric loss, the better. In this Example, 1.5% or less was satisfactory.

(AC breakdown voltage (AC-Eb))

The AC breakdown voltage (AC-Eb) is an AC breakdown voltage per unit thickness by gradually applying an alternating current at 100 V / s to both ends of the capacitor with respect to the capacitor sample, and measuring the voltage at the leakage current of 100 mA. Was obtained. It is preferable that the alternating current breakdown voltage is higher, and in this embodiment, 4.5 kV / mm or more is satisfactory.

(Temperature characteristic (TC))

For capacitor samples, the capacitance was measured at 85 ° C using a digital LCR meter (4284A, manufactured by YHP) at a frequency of 1 kHz and an input signal level (measured voltage) of 1 Vrms. The rate of change (ΔC / C20) (unit is%) of the capacitance at 85 ° C was calculated. In the present embodiment, ΔC / C20 is + 20% to -56%, which satisfies the Z5U characteristic, as a preferred range.

(Sintering)

About the obtained sintered compact, the sintered compact density was computed from the dimension and weight of the sintered compact after baking, and the thing whose sintered compact density is 5.5 g / cm <3> or more was made into (circle) and less than 5.5 g / cm <3>. The reason why the criterion is less than 5.5 g / cm 3 is that when the strength is less than 5.5 g / cm 3, the strength of the substrate is significantly reduced.

From samples 1 to 7, it was confirmed that when m in the composition formula was 0.97 ≦ m ≦ 1.03 (samples 2 to 6), the relative dielectric constant was higher and the AC breakdown voltage was higher than when m was 0.96 (sample 1). . Moreover, when m in a composition formula is 0.97 <= m <= 1.03 (samples 2-6), it was confirmed that sinterability improves compared with the case where m is 1.04 (sample 7). On the other hand, since sample 7 had low sinterability, the relative dielectric constant, dielectric loss, alternating current breakdown voltage, and temperature characteristics could not be measured.

From samples 8-13, when x in a composition formula is 0.03 <= x <= 0.30 (samples 9-12), it was confirmed that sinterability improves compared with the case where x is 0 (sample 8). On the other hand, since sample 8 had low sinterability, the relative dielectric constant, dielectric loss, alternating current breakdown voltage, and temperature characteristics could not be measured. Moreover, when x in a composition formula is 0.03 <= x <= 0.30 (samples 8-13), it was confirmed that the dielectric constant becomes higher compared with the case where x is 0.4 (sample 13).

From samples 14 to 18, it was confirmed that when y in the composition formula was 0 <0 ≤ 0.05 (samples 15 to 17), the relative dielectric constant was higher than when y was 0 (sample 14). Moreover, when y in a composition formula is 0.00 <y <0.05 (samples 15-17), it was confirmed that relative permittivity becomes high and temperature characteristic becomes favorable compared with the case where y is 0.06 (sample 18).

From samples 19 to 26, when z in the composition formula is 0.02 <z≤0.2 (samples 20 to 25), the relative dielectric constant is higher, the dielectric loss is lowered, and the AC breakdown voltage is higher than when z is 0.02 (sample 19). It was confirmed that the increase. Moreover, when z in a composition formula is 0.02 <z <= 0.2 (samples 20-25), it was confirmed that relative permittivity becomes high and temperature characteristic becomes favorable compared with the case where z is 0.25 (sample 26).

From samples 20-25 and 27-32, when a in composition formula is O <= a≤0.2 (samples 20-25, 27-31), relative dielectric constant becomes high compared with the case where a is 0.25 (sample 32), and temperature It was confirmed that the characteristics became good.

From samples 19 and 33 to 37, when z + a in the composition formula is 0.04 ≦ z + a ≦ 0.3 (samples 33 to 36), the relative dielectric constant is higher than when z + a in the composition formula is 0.02 (sample 19). The dielectric loss was lowered and the AC breakdown voltage was increased. Moreover, when z + a in a composition formula is 0.04 <= z + a <0.3 (samples 33-36), relative dielectric constant becomes high and temperature characteristic becomes favorable compared with the case where z + a in a composition formula is 0.40 (sample 37). I could confirm that.

From the samples 38 to 44, when the content of zinc oxide (first subcomponent) is 0.45 to 10% by weight relative to 100% by weight of the main component (samples 39 to 43), when the content of zinc oxide is 0.3% by weight (sample 38 It was confirmed that the sinterability is good compared to). On the other hand, since Sample 38 had low sinterability, the relative dielectric constant, dielectric loss, alternating current breakdown voltage, and temperature characteristics could not be measured. In addition, when the content of zinc oxide (first subcomponent) is 0.45 to 10% by weight (samples 39 to 43) with respect to 100% by weight of the main component, the relative dielectric constant is higher than that of the case where the content of zinc oxide is 15% by weight. I could confirm it.

From samples 4, 45 to 58, La ₂ O ₃ , Pr ₆ O ₁₁ , Pm ₂ O ₃ , Nd ₂ O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O _3, and Y ₂ O as the second accessory ingredient _When the second accessory ingredient consisting of at least one selected from ₃ is contained in an amount of more than 0.0% by weight and 0.3% by weight or less in terms of oxide with respect to 100% by weight of the main ingredient (Samples 4, 45 to 51, 53 to 57) It was confirmed that the AC breakdown voltage was higher than that in the case where the second subcomponent was not included (sample 52). In addition, when the said 2nd subcomponent contains more than 0.3 weight% and 0.3 weight% or less in oxide conversion with respect to 100 weight% of said main components (samples 4, 45-51, 53-57), the said 2nd It was confirmed that the relative dielectric constant was increased and the temperature characteristic was improved as compared with 0.4 wt% of the subcomponent (sample 58).

2… Single Plate Ceramic Capacitors
4… Protection resin
6, 8... Lead terminals
10... Dielectric layer
12,14... Terminal electrode

Claims (2)

_A dielectric ceramic composition having a main component, a first subcomponent, and a second subcomponent represented by the composition formula (Ba _{1- xy} , Ca _x , Sr _y ) _m (Ti _{1 -za} , Zr _z , Sn _a ) O ₃ ,
X in said composition formula is 0.03≤x≤0.30,
Y in the said composition formula is 0.00 <y≤0.05,
Z in the said composition formula is 0.02 <z <= 0.2,
A in said composition formula is O≤a≤0.2,
Z + a in the said composition formula is 0.04 <= z + a <= 0.3,
M in the said composition formula is 0.97 <= m <= 1.03,
The first accessory ingredient is zinc oxide,
The second accessory ingredient is at least one oxide selected from La, Pr, Pm, Nd, Sm, Eu, Gd and Y,
0.45-10 weight% of the said 1st subcomponent is contained with respect to 100 weight% of said main components,
And the second accessory ingredient is more than 0.0% by weight and 0.3% by weight or less in terms of oxide with respect to 100% by weight of the main ingredient. An electronic component having a dielectric layer composed of the dielectric ceramic composition of claim 1.

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