JPH04351804A - Dielectric porcelain composite, and ceramic capacitor and thick film capacitor using said composite - Google Patents

Abstract

PURPOSE:To provide a ceramic capacitor or a thick film capacitor using a dielectric porcelain composite having a baking temperature 800 to 1000 deg.C while the composite can be baked in the atmosphere, neutral atmosphere or reduced atmosphere in a short time and having a low dielectric loss at high frequency. CONSTITUTION:A dielectric porcelain composite is provided with the constitution, in which PbO 1.0 to 25.0 molar % and MgO 10.0 to 200.0 molar % or MnO2 1.0 to 15.0 molar % are added to tentative baked powder of a main component dielectric porcelain composite consisting of Pb(Mg1/3Nb2/3)O3, PbTiO3, Pb(Ni1/2W1/2)O3. Further, the dielectric porcelain composite is also provided with the constitution, in which PbO 1.0 to 25.0 molar % and MgO 10.0 to 250.0 molar % are added to tentative baked powder of the main component dielectric porcelain composite, in which MnO2 is added to a three-component lead solid solution of PbTiO3, Pb(Mg1/3 Nb2/3)O3, PbZrO3.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention has a firing temperature of 800 to 10
The present invention relates to a dielectric ceramic composition that can be fired in a short time at 00°C in a neutral or reducing atmosphere and has low dielectric loss, and to ceramic capacitors and thick film capacitors using the same.

0002

2. Description of the Related Art Materials containing barium titanate as a main component have been used as high dielectric constant materials for ceramic capacitors, which are becoming increasingly smaller and larger in capacity. However, this material must be fired in the atmosphere and at a firing temperature of 1300°C.
Therefore, when manufacturing multilayer ceramic capacitors, it is essential to use expensive noble metals such as platinum or palladium as electrode materials.In particular, as the capacity increases, the cost of raw materials for internal electrode materials increases. This was a factor that pushed up the

On the other hand, in recent years, methods have been developed in which barium titanate-based materials are given reduction resistance and are fired in an atmosphere with low oxygen partial pressure using inexpensive base metals as electrode materials, and lead-based dielectric materials and inexpensive silver The cost of multilayer ceramic capacitors has been reduced by using a silver-palladium alloy electrode material mainly composed of silver and palladium and firing at a low temperature of around 1000°C.

On the other hand, in electronic devices where miniaturization and high reliability are desired, hybrid ICs with high packaging density are being used, and there is an increasing demand for thick film capacitors in place of conventional chip capacitors. To manufacture thick film capacitors, a dielectric material that can be fired at low temperatures and in a short time is required, and lead-based dielectric materials are mainly used as the material for this purpose. Therefore, lead-based dielectrics are being actively developed as materials that can be fired at low temperatures and can be used to increase the capacity of multilayer chip capacitors or to increase the thickness of capacitors.

[0005]

[Problem to be solved by the invention] Now, Pb(Mg1/
3Nb2/3)O3,PbTiO3,Pb(Ni1/2
W1/2) O3-based dielectric composition is disclosed in Japanese Patent Application Laid-open No. 61-155.
As known from Publication No. 249, this is a high dielectric constant ceramic composition that is fired in the atmosphere at temperatures below 1100°C. Need to keep time.

[0006] Also, PbTiO3, Pb(Mg1/3N
b2/3) A dielectric ceramic composition with low dielectric loss in which MnO2 is added to O3, PbZrO3 is disclosed in Japanese Patent Publication No. 46-42544.
As is known from publications such as the above, it is a ferroelectric ceramic composition, but in order to increase the dielectric constant and obtain a sufficiently dense fired body, it is necessary to hold it at a firing temperature of 1250°C or higher for several hours. . Therefore, when forming the dielectric and the electrode by co-firing, an inexpensive base metal with a low melting point cannot be used as the electrode material. On the other hand, when producing thick film capacitors for hybrid ICs, low-temperature, short-time firing is essential, and under such conditions the dielectric material becomes unfired, making it impossible to obtain the desired characteristics. .

In view of this problem, the present invention provides Pb (Mg
1/3Nb2/3)O3,PbTiO3,Pb(Ni1
/2W1/2) O3-based solid and PbTiO3, Pb
(Mg1/3Nb2/3)O3, PbZrO3-based solid medium does not lose its dielectric constant, can be fired at 800 to 1000℃ in a neutral or reducing atmosphere for a short time, and has low dielectric loss. The object of the present invention is to provide a ceramic composition and a ceramic capacitor and a thick film capacitor using the same.

[0008]

[Means for Solving the Problems] In order to solve the above problems, the dielectric ceramic composition of the present invention has Pb(Mg1/3N
b2/3) xTiy(Ni1/2W1/2)zO3 In the porcelain composition (x+y+z=1),
Pb(Mg1/3Nb2/3)O3,PbTiO3,P
In triangular coordinates with b(Ni1/2W1/2)O3 as the vertex, the compositions A, B, C, expressed by the numbers in [ ] below,
1.0 to 25.0 mol% of PbO and 10.0 to 25.0 mol% of MgO are added as subcomponents to the calcined powder of the main component dielectric ceramic composition consisting of a pentagonal region with vertices D and E. 200
．． It has a structure in which 0 mol % or 1.0 to 15.0 mol % of MnO2 is added.

[A is x=0.025, y=0.950, z=0.
025 B is x=0.125, y=0.850,
z=0.025 C is x=0.600, y=0.
100, z=0.300 D is x=0.400,
y=0.100, z=0.500 E is x=0.
025, y=0.900, z=0.075] Furthermore, the dielectric ceramic composition of the present invention includes PbTix (Mg1/3Nb
2/3) In the ceramic composition represented by yZrzO3+mMnO2 (however, x+y+z=1), m=0.1 to 3
．． It is in the range of 0 wt%, and for the value of m within this range,
PbTiO3,Pb(Mg1/3Nb2/3)O3,P
A main component dielectric ceramic composition consisting of a hexagonal region with compositions A, B, C, D, E, and F as vertices, represented by the numbers in brackets below in triangular coordinates with bZrO3 as the apex. 1.0 to 25% of PbO was added as a subcomponent to the calcined powder.
0 mol % and MgO is added in an amount of 10.0 to 250.0 mol %.

[A is x=0.250, y=0.125,
z=0.625 B is x=0.3125, y=0
．． 0625, z=0.625 C is x=0.50
0, y=0.0625, z=0.4325
D is x=0.500, y=0.450, z=0
．． 050 E is x=0.450, y=0.5
00, z=0.050 F is x=0.250
, y=0.500, z=0.250]

001
1]

[Function] In the dielectric ceramic composition of the present invention, Pb(Mg1/3Nb2/3)O having a perovskite structure
3-PbTiO3-Pb(Ni1/2W1/2)O3-based calcined powder is added with PbO and MgO or MnO2, or PbTi having a perovskite structure is added.
O3, Pb (Mg1/3Nb2/3) O3, PbZrO
3. By adding PbO and MgO to MnO2-based calcined powder, a liquid phase is generated at low temperature by utilizing the eutectic composition of PbO and MgO or MnO2, and these additives By immobilizing at the same time as the site, diffusion into the dielectric material is performed smoothly. Therefore, the formation of grain boundary layers due to additives can be suppressed, and a decrease in dielectric constant and an increase in dielectric loss can be prevented. Therefore, it is possible to obtain a ceramic capacitor and a thick film capacitor that can be fired to a high density in a short time at a low firing temperature of 1000° C. or less in a neutral atmosphere or a reducing atmosphere.

0012

【Example】

(Example 1) Hereinafter, a dielectric ceramic composition according to an example of the present invention, and a ceramic capacitor and a thick film capacitor using the same will be described.

First, chemically highly pure PbO, MgO, Nb2O5, TiO2, and MnO2 were used as starting materials. Weigh the specified amount after correcting the purity of these,
Pure water was added and mixed for 17 hours in a ball mill using agate stones. This was filtered by suction, most of the water was separated, and then dried. After that, it was thoroughly crushed in a Raikai machine, and then 5 wt% of pure water was added to the crushed amount, and it was molded into a cylindrical shape with a diameter of 60 mm and a height of about 50 mm at a pressure of 500 kg/ It was molded in cm2. Place this in an aluminum pot and cover with a homogeneous lid.
It was calcined at 00°C for 2 hours. Next, the calcined product was roughly crushed in an alumina mortar, further crushed in a ball mill for 17 hours, filtered under suction, and then dried. The above steps of calcination, crushing, and drying were repeated several times. This powder was analyzed by X-ray analysis and confirmed to be a perovskite phase.

[0014] This dielectric powder contains PbO as an accessory component,
After adding MgO or MnO2 and mixing with a Raikai machine, add 6wt% polyvinyl alcohol aqueous solution to 6w of powder amount.
t% was added, and the mixture was granulated through a 32-mesh sieve, and molded into a disk shape with a diameter of 13 mm and a height of about 5 mm at a molding pressure of 500 kg/cm2. Next, this molded product was heated to 600°C in the atmosphere.
After holding for 1 hour to remove the binder, the container was placed in a magnesia porcelain container, covered with a homogeneous lid, and heated to a predetermined temperature at 240°C in a neutral or reducing atmosphere using an atmospheric belt furnace.
After raising the temperature at 0℃/hrs and holding it at the maximum temperature for 10 minutes,
The temperature was lowered at 400°C/hrs.

[0015] The fired product obtained as described above has a thickness of 1
It was processed into a disk shape of mm in diameter, Cr-Ag was deposited on both sides as electrodes, and the dielectric constant and tan δ were measured under an electric field of 1 KHz and 1 V/mm.

The following (Table 1) shows the material composition of this example,
The dielectric properties and dielectric loss of the fired product are shown when the firing atmosphere is nitrogen, which is a neutral atmosphere.

[0017]

[Table 1]

Table 2 below shows the dielectric properties and dielectric loss of the dielectric ceramic composition when the firing atmosphere is a nitrogen-hydrogen mixed gas having an oxygen partial pressure of 10 -8 atm or more.

[0019]

[Table 2]

As shown in Tables 1 and 2 above, according to the examples, high-permittivity dense particles were obtained despite short-time firing at 800 to 1000°C and under various atmosphere firings. A fired body is obtained, and MgO or Mn is used as an auxiliary agent.
By adding O2, a fired product having low dielectric loss can be obtained even when fired in a neutral atmosphere or a reducing atmosphere.

FIG. 1 shows the composition range of the main component of the present invention.
(Mg1/3Nb2/3)O3,PbTiO3,Pb(
Although this is shown in the triangular composition diagram whose main component is Ni1/2W1/2)O3, the scope of claims in the present invention is defined as Pb(Mg1/3Nb2/3)xTiy(
In the ceramic composition represented by Ni1/2W1/2)zO3 (where x+y+z=1), Pb(Mg1/3Nb
2/3) O3, PbTiO3, Pb(Ni1/2W1/
2) Composition A, B, C, D, E represented by the numerical values in brackets below in triangular coordinates with O3 as the vertex. Based on the calcined powder, 1.0 to 25.0 mol% of PbO and 10.0 to 200.0 mol% of MgO or Mn are added as subcomponents.
A dielectric ceramic composition characterized in that 1.0 to 15.0 mol% of O2 is added [A is x=0.025, y=0.950, z=0.
025 B is x=0.125, y=0.850,
z=0.025 C is x=0.600, y=0.
100, z=0.300 D is x=0.400,
y=0.100, z=0.500 E is x=0.
025, y=0.900, z=0.075], the reason for the specific limitation will be described. As shown in the comparative examples (Table 1) and (Table 2), in compositions outside the scope of the invention, compositions with a small amount of auxiliary additives and firing temperatures lower than 800°C result in insufficient firing, resulting in dense particles. If a fired body cannot be obtained, and if the composition contains a large amount of additives and the firing temperature is higher than 1000℃, the dielectric constant will decrease significantly due to the reaction of the additive with the dielectric, and the dielectric loss will increase. have. Furthermore, a composition in which x, y, and z are outside the specified ranges has the disadvantage that a high dielectric constant and low dielectric loss cannot be obtained. As mentioned above, if the composition is outside the limited range, the dielectric constant of the fired product will be less than 2000 or the dielectric loss will be more than 1.5% under the main firing conditions, making it impossible to obtain the desired characteristics as a capacitor. It's for a reason.

(Example 2) Similar to Example 1 above, calcination and
PbO and M are added as subcomponents to the crushed and dried dielectric powder.
gO or MnO2 was added, wet mixed in a ball mill, and then dried. A vehicle in which a resin containing ethyl cellulose as a main component was dissolved in a solvent was added, and the mixture was kneaded with a three-stage roll to prepare a dielectric paste. On the other hand, in order to form a thick film capacitor having a shape of 2 x 2 mm2 on an alumina substrate with a purity of 96%, a copper electrode was printed as a lower electrode and dried. Next, the dielectric paste was printed and dried twice to a thickness of 0.050 to 0.060 mm as a dielectric layer, and a copper electrode, which was the same as the lower electrode, was printed and dried as an upper electrode. A printed thick film having a three-layer structure of -dielectric material-electrode was formed and fired in nitrogen using a belt furnace at a maximum temperature of 800 to 1000°C for a holding time of 10 minutes. The dielectric constant of the thick film capacitor obtained in this way, ta
nδ was measured at 1 KHz under an electric field of 1 V/mm. (Table 3) shows the material composition of this example, and the dielectric properties and dielectric loss of the fired product fired at 900° C. in nitrogen.

[0023]

[Table 3]

As shown in Table 3 above, the fired product of the material composition of this example is a dense fired product with a high dielectric constant and low dielectric loss despite being fired at a low temperature for a short time. A thick film capacitor is obtained.

The reason for limiting the scope of the claims is that, as in Example 1, as shown in the comparative example in Table 3, for compositions outside the limited range, the dielectric constant of the fired product is 1000 under the main firing conditions.
This is because the dielectric loss is less than 1.0% or more than 1.0%, making it impossible to obtain desired characteristics as a thick film capacitor.

In this example, it was shown that firing was possible in nitrogen, but it is easily inferred that firing is also possible in a neutral atmosphere such as argon or helium.

[0027] The electrode used in this example has a temperature of 800 to 10 in a neutral atmosphere or a reducing atmosphere.
An electrode that can be fired at 00°C is appropriately selected and used.

(Example 3) A dielectric ceramic composition according to another example of the present invention, and a ceramic capacitor and a thick film capacitor using the same will be described below.

First, as starting materials, chemically highly pure PbO, MgO, Nb2O5, TiO2, ZrO2, M
nO2 was used. After correcting the purity of these, a predetermined amount was weighed, pure water was added, and the mixture was mixed for 17 hours in a ball mill using agate cobblestones. This is filtered by suction to remove most of the moisture, dried, and then thoroughly crushed using a Raikai machine. 5wt% of pure water is added to the crushed amount, and the mixture is molded into a cylinder with a diameter of 60mm and a height of approximately 50mm under a pressure of 500kg. /cm2. Place this in an aluminum pot, cover with a homogeneous lid, and
Calcining was performed at 50 to 1150°C for 2 hours. Next, the calcined product was roughly crushed in an alumina mortar, further crushed in a ball mill for 17 hours, filtered under suction, and then dried. Calcining, crushing,
Drying was repeated several times. This powder was analyzed by X-ray analysis and confirmed to be a perovskite phase.

[0030] This dielectric powder contains PbO as an accessory component,
After adding MgO and mixing with a Raikai machine, 6 wt% aqueous solution of polyvinyl alcohol was added to 6 wt% of the powder amount.
Granulated through a mesh sieve and molded at a pressure of 500 kg/
It was molded into a disk shape with a diameter of 13 mm and a height of about 5 mm. Next, this molded product is held in the atmosphere at 600°C for 1 hour to remove the binder, then placed in a magnesia porcelain container with a homogeneous lid, and heated in the atmosphere, neutral atmosphere, or reducing atmosphere using an atmospheric belt furnace. up to a specified temperature of 2400℃/
After raising the temperature at hrs and holding it at the maximum temperature for 10 minutes, it was heated to 2400 hrs.
The temperature was lowered at °C/hrs.

[0031] The fired product obtained as described above has a thickness of 1
It was processed into a disk shape of mm in diameter, Cr-Ag was deposited on both sides as electrodes, and the dielectric constant and tan δ were measured under an electric field of 1 MHz and 1 V/mm.

The following (Table 4) shows the material composition of this example,
The dielectric properties and dielectric loss of the fired product in the atmosphere are shown.

[0033]

[Table 4]

[0034] In addition, the dielectric properties of the dielectric ceramic composition are also evaluated when the firing atmosphere is nitrogen, which is a neutral atmosphere, and when the firing atmosphere is a nitrogen-hydrogen mixed gas having an oxygen partial pressure of 10-8 atm or more. The characteristics and dielectric loss are shown below (
Table 5) and (Table 6).

[0035]

[Table 5]

[0036]

[Table 6]

As shown in the above (Table 4), according to the examples, despite short-time firing at 800 to 1000°C, by adding PbO and MgO or MnO2 to the auxiliary agents, high A dense fired body with a low dielectric constant and low dielectric loss can be obtained. Furthermore, for the composition within the scope of the patent when fired in the air, a sintered body having the above characteristics was obtained even when fired in a neutral atmosphere or a reducing atmosphere as shown in Tables 5 and 6. .

FIG. 2 shows the composition range of the main component of the present invention.
TiO3,Pb(Mg1/3Nb2/3)O3,Pb(
It is shown in the triangular composition diagram whose main component is PbTix(Mg1/3Nb2/3)O3.
Porcelain composition expressed as rzO3+mMnO2 (where x
+y+z=1), m is in the range of 0.1 to 3.0 wt%, and for the value of m within this range, PbTiO3
, Pb(Mg1/3Nb2/3)O3, Pb(Ni1/
2W1/2) In triangular coordinates with O3 as the vertex, the following [
] PbO as a subcomponent for the calcined powder of a dielectric ceramic composition as a main component consisting of a hexagonal area with compositions A, B, C, D, E, and F as vertices, represented by the numerical values in 1.0~
25.0 mol% and MgO 10.0 to 250.0 mol%
A dielectric ceramic composition characterized in that [A is x=0.250, y=0.125,
z=0.625 B is x=0.3125, y=0
．． 0625, z=0.625 C is x=0.50
0, y=0.0625, z=0.4325
D is x=0.500, y=0.450, z=0
．． 050 E is x=0.450, y=0.5
00, z=0.050 F is x=0.250
, y=0.500, z=0.250], the reason for the specific limitation will be described. (Table 4), (Table 5), (Table 6
), in compositions outside the scope of the invention, compositions in which the amount of additives added and firing temperatures lower than 800°C result in insufficient firing and a dense fired body cannot be obtained. Compositions in which a large amount of additives are added and firing temperatures higher than 1000° C. have the drawback that the dielectric constant decreases due to the reaction of the additives with the dielectric material, and dielectric loss increases. Furthermore, a composition in which x, y, and z are outside the specified ranges has the disadvantage that a high dielectric constant and low dielectric loss cannot be obtained. As mentioned above, if the composition is outside the limited range, specifically, the dielectric constant of the fired body is 200 or less and the dielectric loss is 1 under the main firing conditions.
．． This is because it becomes 0% or more and the desired characteristics as a capacitor cannot be obtained.

(Example 4) Calcination and
PbO and M are added as subcomponents to the crushed and dried dielectric powder.
gO or MnO2 was added, wet mixed in a ball mill, and then dried. A vehicle in which a resin containing ethyl cellulose as a main component was dissolved in a solvent was added, and the mixture was kneaded with a three-stage roll to prepare a dielectric paste. On the other hand, in order to form a thick film capacitor having a shape of 2 x 2 mm2 on an alumina substrate with a purity of 96%, an electrode paste was printed and dried as a lower electrode. Next, the dielectric paste was printed and dried twice to a thickness of 0.050 to 0.060 mm as a dielectric layer, and the same electrode paste as the lower electrode was printed and dried as an upper electrode. A printed thick film having a three-layer structure of -dielectric material-electrode was formed and fired using a belt furnace at a maximum temperature of 800 to 1000°C for a holding time of 10 minutes. The dielectric constant, tan δ, of the thick film capacitor thus obtained was measured under an electric field of 1 KHz and 1 V/mm. (Table 7) shows the material composition of this example and the temperature at 900°C in the atmosphere.
The dielectric properties and dielectric loss of the fired product are shown below.

[0040]

[Table 7]

As shown in Table 7 above, the fired product of the material composition of this example is a dense fired product with a high dielectric constant and low dielectric loss despite being fired at a low temperature for a short time. A thick film capacitor is obtained.

Table 8 also shows the material composition of this example, and the dielectric properties and dielectric loss of the fired product fired at 900° C. in nitrogen.

[0043]

[Table 8]

As shown in Table 8 above, the fired product of the material composition of this example is a dense fired product with a high dielectric constant and low dielectric loss despite being fired at a low temperature for a short time. A thick film capacitor is obtained.

[0045] The reason for limiting the scope of the claims is that, as in Example 1, as shown in the comparative examples (Table 7) and (Table 8), with a composition outside the limited range, the fired product cannot be produced under the main firing conditions. This is because the dielectric constant of the capacitor is 200 or less, or the dielectric loss is 1.0% or more, making it impossible to obtain the desired characteristics as a thick film capacitor.

[0046] In this example, it was shown that firing is possible in nitrogen, but it is easily inferred that firing is also possible in a neutral atmosphere such as argon or helium.

[0047] The electrodes used in this example were tested at 80°C in air, neutral atmosphere, or reducing atmosphere.
An electrode that can be fired at 0 to 1000°C is appropriately selected and used.

[0048]

[Effects of the Invention] As described above, according to the present invention, 80
A dielectric material that has a high dielectric constant that can be fired at a temperature of 0 to 1000°C in a short time and even in a neutral atmosphere or a reducing atmosphere, and that can provide multilayer ceramic capacitors and thick film capacitors with low dielectric loss. This exhibits the excellent effect of realizing a porcelain composition.

[Brief explanation of the drawing]

Claims (1)

[Scope of Claims] [Claim 1] A main component dielectric ceramic composition obtained by calcining and pulverizing a lead-based dielectric ceramic composition containing Pb(Mg1/3Nb2/3)O3, PbO and Mg as components
A dielectric ceramic composition characterized by adding O or MnO2. Claim 2: Pb(Mg1/3Nb2/3)xTiy(
In the ceramic composition represented by Ni1/2W1/2)zO3 (where x+y+z=1), Pb(Mg1/3Nb
2/3) O3, PbTiO3, Pb(Ni1/2W1/
2) Composition A, B, C, D, E represented by the numerical values in square brackets below in triangular coordinates with O3 as the vertex. Based on the calcined powder, 1.0 to 25.0 mol% of PbO and 10.0 to 200.0 mol% of MgO or MnO2 are added as subcomponents.
A dielectric ceramic composition characterized in that 1.0 to 15.0 mol% of is added. [A is x=0.025, y=0.950, z=0.
025 B is x=0.125, y=0.850,
z=0.025 C is x=0.600, y=0.
100, z=0.300 D is x=0.400,
y=0.100, z=0.500 E is x=0.
025, y=0.900, z=0.075] [Claim 3
]PbTix(Mg1/3Nb2/3)yZrzO3+
Porcelain composition expressed in mMnO2 (where x+y+z=
1), m is in the range of 0.1 to 3.0 wt%, and for the value of m within this range, PbTiO3, Pb(M
Composition A expressed by the numbers in [ ] below in triangular coordinates with g1/3Nb2/3)O3, PbZrO3 as the apex
, B, C, D, E, and F as the vertices of the calcined powder of the dielectric ceramic composition as the main component, 1.0 to 25.0 mol% of PbO is added as a subcomponent. and 1 MgO
A dielectric ceramic composition characterized in that it is added in an amount of 0.0 to 250.0 mol%. [A is x=0.250, y=0.125,
z=0.625 B is x=0.3125, y=0
．． 0625, z=0.625 C is x=0.50
0, y=0.0625, z=0.4325
D is x=0.500, y=0.450, z=0
．． 050 E is x=0.450, y=0.5
00, z=0.050 F is x=0.250
, y=0.500, z=0.250] [Claim 4] A dielectric layer made of the dielectric ceramic composition according to claim 2 or 3, and 8.
A ceramic capacitor comprising an electrode that can be fired at a temperature of 00 to 1000°C. 5. A dielectric layer comprising the dielectric ceramic composition according to claim 2 or 3 on a ceramic substrate;
A thick film capacitor comprising an electrode that can be fired at 000°C.