# US 2015/0103467 A1 · Multilayer ceramic capacitor and method of manufacturing the same

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- Number: US 2015/0103467 A1
- Document ID: US20150103467A1
- Status: Published application
- Kind: A1
- Application number: 14/574,796
- Filed: 2014-12-18
- Published: 2015-04-16
- Earliest claimed: 2012-07-10
- Assignees: Murata Manufacturing Co., Ltd.
- Applicants: Murata Manufacturing Co., Ltd.
- Inventors: Takafumi OKAMOTO
- Web page: https://patentgrep.com/patent/US20150103467A1

## CPC

- H01G 4/1227: {based on alkaline earth titanates}
- C04B 35/4682: {based on BaTiO3 perovskite phase}
- C04B 35/6261: {Milling}
- H01G 4/30: Stacked capacitors (H01G4/33 takes precedence)
- C04B 2235/3206: Magnesium oxides or oxide-forming salts thereof
- C04B 2235/3208: Calcium oxide or oxide-forming salts thereof, e.g. lime
- C04B 2235/3213: Strontium oxides or oxide-forming salts thereof
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3224: Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
- C04B 2235/3227: Lanthanum oxide or oxide-forming salts thereof
- C04B 2235/3244: Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
- C04B 2235/3262: Manganese oxides, manganates, rhenium oxides or oxide-forming salts thereof, e.g. MnO
- C04B 2235/6025: Tape casting, e.g. with a doctor blade
- C04B 2235/6582: Hydrogen containing atmosphere
- C04B 2235/6588: Water vapor containing atmospheres
- Y10T 29/435: Solid dielectric type
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A multilayer ceramic capacitor includes a multilayer body including a plurality of stacked dielectric layers including a dielectric ceramic that includes a plurality of crystal grains and a plurality of internal electrodes disposed at a plurality of interfaces between the dielectric layers, and external electrodes. The multilayer body includes a Ba and Ti containing perovskite compound, La, Mg, Mn and Al, and satisfies conditions such that in a case in which a content of Ti is set to 100 molar parts, a fraction of each content of La, Mg, Mn and Al relative to the content of Ti is such that La is about 0.2 to about 1.2 molar parts, Mg is about 0.1 molar part or less, Mn is about 1.0 to about 3.0 molar parts and Al is about 0.5 to about 2.5 molar parts, and an average number of crystal grains included in each of the dielectric layers in the stacking direction is one or more to three or less.

## Claims

### Claim 1

(canceled)

### Claim 2

A multilayer ceramic capacitor comprising:
a multilayer body including a plurality of stacked dielectric layers including a dielectric ceramic that includes a plurality of crystal grains and a plurality of internal electrodes disposed at a plurality of interfaces between the dielectric layers; and
an external electrode provided on an outer surface of the multilayer body and electrically connected to some of the plurality of inner electrode; wherein
the multilayer body includes a Ba and Ti containing perovskite compound, and La, Mg, Mn and Al;
in a case in which a content of Ti is set to 100 molar parts, a fraction of each content of La, Mg, Mn and Al relative to the content of Ti is such that La is about 0.2 to about 1.2 molar parts, Mg is about 0.1 molar part or less, Mn is about 1.0 to about 3.0 molar parts and Al is about 0.5 to about 2.5 molar parts; and
an average number of the crystal grains included in each of the plurality of dielectric layers in a stacking direction is one or more to three or less.

### Claim 3 (depends on 2)

The multilayer ceramic capacitor according to claim 2, wherein the multilayer body includes a width of about 1.0 mm, a length of about 2.0 mm, and a thickness of about 0.4 mm, and a thickness of each of the plurality of dielectric layer is about 2.0 μm, and a thickness of each of the plurality of internal electrodes is about 1.0 μm.

### Claim 4

A multilayer ceramic capacitor comprising:
a multilayer body including a plurality of stacked dielectric layers including a dielectric ceramic that includes a plurality of crystal grains and a plurality of internal electrodes disposed at a plurality of interfaces between the dielectric layers; and
an external electrode provided on an outer surface of the multilayer body and electrically connected to some of the plurality of inner electrode; wherein
the multilayer body includes a Ba and Ti containing perovskite compound, and La, Mg, Mn and Al;
in a case in which the multilayer body is subjected to a dissolution treatment to form a solution and a content of Ti is set to 100 molar parts, a fraction of each content of La, Mg, Mn and Al relative to the content of Ti is such that La is about 0.2 to about 1.2 molar parts, Mg is about 0.1 molar part or less, Mn is about 1.0 to about 3.0 molar parts and Al is about 0.5 to about 2.5 molar parts; and
an average number of the crystal grains included in each of the plurality of dielectric layers in a stacking direction is one or more to three or less.

### Claim 5 (depends on 4)

The multilayer ceramic capacitor according to claim 4, wherein the multilayer body includes a width of about 1.0 mm, a length of about 2.0 mm, and a thickness of about 0.4 mm, and a thickness of each of the plurality of dielectric layer is about 2.0 μm, and a thickness of each of the plurality of internal electrodes is about 1.0 μm.

### Claim 6

A multilayer ceramic capacitor comprising:
a multilayer body including a plurality of stacked dielectric layers including a dielectric ceramic that includes a plurality of crystal grains and a plurality of internal electrodes disposed at a plurality of interfaces between the dielectric layers; and
an external electrode provided on an outer surface of the multilayer body and electrically connected to some of the plurality of inner electrode; wherein
the plurality of dielectric layers include a Ba and Ti containing perovskite compound, and La, Mg, Mn and Al;
in a case in which a content of Ti is set to 100 molar parts, a fraction of each content of La, Mg, Mn and Al relative to the content of Ti is such that La is about 0.2 to about 1.2 molar parts, Mg is about 0.1 molar part or less, Mn is about 1.0 to about 3.0 molar parts and Al is about 0.5 to about 2.5 molar parts; and
an average number of the crystal grains included in each of the dielectric layers in a stacking direction is one or more to three or less
an average number of the crystal grains included in each of the plurality of dielectric layers in the stacking direction being one or more to three or less.

### Claim 7 (depends on 6)

The multilayer ceramic capacitor according to claim 6, wherein the multilayer body includes a width of about 1.0 mm, a length of about 2.0 mm, and a thickness of about 0.4 mm, and a thickness of each of the plurality of dielectric layer is about 2.0 μm, and a thickness of each of the plurality of internal electrodes is about 1.0 μm.

### Claim 8

A method for manufacturing a multilayer ceramic capacitor which includes a multilayer body provided with a plurality of stacked dielectric layers including a dielectric ceramic that includes a plurality of crystal grains and a plurality of internal electrodes disposed at a plurality of interfaces between the dielectric layers, the method comprising the steps of:
preparing a ceramic slurry by blending powder including a Ba and Ti containing perovskite compound, an La containing compound powder, an Mg containing compound powder, an Mn containing compound powder and an Al containing compound powder into a slurry in which a content of Ti is set to 100 molar parts, a fraction of each content of La, Mg, Mn and Al relative to the content of Ti is such that La is about 0.2 to about 1.2 molar parts, Mg is about 0.1 molar part or less, Mn is about 1.0 to about 3.0 molar parts and Al is about 0.5 to about 2.5 molar parts;
obtaining a ceramic green sheet by forming the ceramic slurry into a sheet;
providing an unfired multilayer body by stacking the ceramic green sheet and a conductor pattern which defines the plurality of internal electrodes after firing; and
firing the unfired multilayer body to provide the multilayer body which is configured in such a manner that each of the plurality of internal electrodes are disposed between adjacent pairs of the plurality of dielectric layers, and an average number of the crystal grains included in each of the dielectric layers in a stacking direction is one or more to three or less.

### Claim 9 (depends on 8)

The method according to claim 8, wherein each powder was weighed such that the fraction of the content of Ba relative to the content of Ti is 102.5 molar parts relative to 100 molar parts of Ti.

### Claim 10 (depends on 8)

The method according to claim 8, wherein the blending was performed by mixing in a ball mill while using water as a medium, pre-firing and pulverizing to provide a ceramic powder.

### Claim 11 (depends on 8)

The method according to claim 8, wherein in the Ba and Ti containing perovskite compound, Ca and Sr are included in a site of Ba, and Zr and Hf are included in a site of Ti.

### Claim 12 (depends on 8)

The method according to claim 8, wherein the step of preparing the ceramic slurry includes adding R2O3 (R=La, Gd, Dy), Al2O3, MgCO3 and MnCO3 to the perovskite compound powder.

### Claim 13 (depends on 8)

The method according to claim 8, wherein the step of preparing the ceramic slurry includes adding a polyvinyl butyral-based binder and an organic solvent, and wet blending by a ball mill to prepare the ceramic slurry.

### Claim 14 (depends on 8)

The method according to claim 8, wherein the step of forming the ceramic slurry into the sheet by a doctor blade method.

### Claim 15 (depends on 8)

The method according to claim 8, wherein a thickness of the sheet is about 2.0 μm.

### Claim 16 (depends on 8)

The method according to claim 8, wherein the step of firing is performed at temperature of about 1160° C. to about 1260° C.

### Claim 17 (depends on 8)

The method according to claim 8, further comprising forming external electrodes on end surfaces of the fired multilayer body.

### Claim 18 (depends on 8)

The method according to claim 8, wherein the fired multilayer body includes a width of about 1.0 mm, a length of about 2.0 mm, and a thickness of about 0.4 mm, and a thickness of each of the plurality of dielectric layer is about 2.0 μm, and a thickness of each of the plurality of internal electrodes is about 1.0 μm.