JP7243175B2 - Apparatus for Determining Quality of Multilayer Ceramic Capacitor and Method for Determining Quality Thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for judging the quality of a multilayer ceramic capacitor and a method for judging the same, and more particularly, to a device for judging the quality of a multilayer ceramic capacitor for judging whether the electrical characteristics of the multilayer ceramic capacitor are good or bad based on the result of measuring the insulation resistance of the multilayer ceramic capacitor. and its quality judgment method.

In general, multilayer ceramic capacitors used in electronic devices and the like are usually measured for electrical characteristics such as capacitance and insulation resistance in an inspection process before being shipped to the market. Then, based on the measurement results, the laminated ceramic capacitors are sorted into non-defective products and defective products.
In particular, in a method for measuring the insulation resistance of a multilayer ceramic capacitor, first, charging terminals are brought into contact with the multilayer ceramic capacitors held, for example, in the holding portions of the turntable, and the multilayer ceramic capacitor is intermittently charged with a DC voltage. is transported intermittently on the turntable. In this case, the charging terminal contacts the multilayer ceramic capacitor only while the turntable is stopped, and no charging terminal contacts the multilayer ceramic capacitor until the turntable rotates and contacts the next charging terminal. Therefore, the charging of the multilayer ceramic capacitor in the charging region is intermittent.
Next, the insulation resistance is measured by applying a measuring terminal to the laminated ceramic capacitor that has been fully charged. Then, based on the measurement results of the insulation resistance, the laminated ceramic capacitors are sorted into non-defective products and defective products (see FIG. 2 of Patent Document 1, for example).

Japanese Patent Application Laid-Open No. 4-254769 (page 1, column 2, line 5 to page 2, column 3, line 21, FIG. 2)

However, in such a conventional quality judgment of laminated ceramic capacitors, if the voltage range in which the laminated ceramic capacitor is used is, for example, DC: 750 V or higher, a problem may occur.
Specifically, in the conventional process of measuring the insulation resistance described above, since the charging of the multilayer ceramic capacitor in the charging region is intermittent, the multilayer ceramic capacitor remains charged until the next step. It is transported to the insulation resistance measurement position and the insulation resistance is measured.
On the other hand, the discharge side (negative side) measurement terminal at the discharge position is short-circuited to the GND electrode of the mounting substrate, and the potential is 0 V (zero volt). When the potential difference between laminated ceramic capacitors exceeded, for example, 3 KV/mm, sparks (dielectric breakdown) were generally likely to occur.
In this case, when the voltage range in which the multilayer ceramic capacitor is used is, for example, DC: 750 V or higher, the external electrodes of the multilayer ceramic capacitor and the terminals for measuring the insulation resistance in contact with the external electrodes of the multilayer ceramic capacitor are used. Since the potential difference between (the measurement terminal) and , becomes large, a larger spark may occur.
As a result of intensive research by the inventor of the present invention, the noise generated by this large spark can cause, for example, communication troubles between the control personal computer of the measuring equipment and the IR meter, making it impossible to measure the insulation resistance, and It was found that there was a problem that the

SUMMARY OF THE INVENTION Therefore, it is a primary object of the present invention to provide a device for judging quality of a multilayer ceramic capacitor and a method for judging quality thereof, which can solve the above problems.
In other words, when measuring the insulation resistance of a multilayer ceramic capacitor, the energy of the spark generated between the measurement terminals and the multilayer ceramic capacitor can be suppressed, and the noise generated by this spark can be suppressed. An object of the present invention is to provide an apparatus and a method for judging whether the apparatus is good or bad.

The present invention according to claim 1 provides a plurality of laminated ceramics having a laminate having a plurality of laminated dielectric layers and a plurality of laminated internal electrode layers, and an external electrode connected to the plurality of internal electrodes A conveying means for holding and conveying capacitors, an applying circuit and charging terminals for continuously charging a plurality of laminated ceramic capacitors with a DC voltage equal to or higher than the rated voltage of the laminated ceramic capacitors, and the charged laminated ceramic capacitors. A device for judging quality of a laminated ceramic capacitor, comprising: a discharge circuit for discharging electric charge within a predetermined range with respect to an applied voltage; and a measuring terminal for measuring insulation resistance of the laminated ceramic capacitor after discharging. Then, an application circuit continuously charges a plurality of multilayer ceramic capacitors with a DC voltage higher than the rated voltage of the multilayer ceramic capacitors for a certain period of time, and a discharge circuit temporarily discharges the charged multilayer ceramic capacitors with the applied voltage. is discharged in a predetermined range, the measurement terminal is brought into contact with the external electrode for the laminated ceramic capacitor after discharge, and the measurement terminal is brought into contact with the external electrode, and then the application circuit is applied again to the laminated ceramic capacitor. is charged with a DC voltage equal to or higher than the rated voltage of the multilayer ceramic capacitor, and then the insulation resistance is measured to determine the quality of the multilayer ceramic capacitor.
The present invention according to claim 2 is an invention dependent on the device for judging quality of laminated ceramic capacitors according to claim 1, wherein the conveying means includes a conveying rotor.
The present invention according to claim 3 is an invention dependent on the device for judging quality of a laminated ceramic capacitor according to claim 1 or claim 2, wherein the discharge circuit includes a resistor. .
The present invention according to claim 4 is an invention dependent on the device for judging quality of a multilayer ceramic capacitor according to claim 1, wherein the discharge resistor for discharging electric charge within a predetermined range with respect to the applied voltage It is a device for judging quality of a multilayer ceramic capacitor that discharges electric charge in the range of 50% or more and 70% or less with respect to

According to the device for judging quality of a laminated ceramic capacitor and the method for judging quality thereof of the present invention, it is possible to suppress the energy of sparks generated between the measuring terminals and the laminated ceramic capacitor when measuring the insulation resistance of the laminated ceramic capacitor. There is an effect that it is possible to obtain a device for judging quality of a laminated ceramic capacitor and a method for judging quality thereof, which can suppress noise generated by the spark.

The above object, other objects, features and advantages of the present invention will become more apparent from the following description of the mode for carrying out the invention with reference to the drawings.

1 is an external perspective view showing an example of a laminated ceramic capacitor according to the present invention; FIG. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, showing the multilayer ceramic capacitor according to the present invention; FIG. 2 is a cross-sectional view taken along line III-III of FIG. 1, showing a multilayer ceramic capacitor according to the present invention; (a) is a diagram showing a structure in which a counter electrode portion of an internal electrode layer of a laminate in a multilayer ceramic capacitor according to the present invention is divided into two. (b) is a diagram showing a structure in which the counter electrode portion of the internal electrode layer of the laminate in the multilayer ceramic capacitor according to the present invention is divided into three. (c) is a diagram showing a structure in which the counter electrode portion of the internal electrode layer of the laminate in the multilayer ceramic capacitor according to the present invention is divided into four. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view schematically showing an example of a device for judging quality of a laminated ceramic capacitor according to the present invention; FIG. 6 is an explanatory diagram illustrating a cross-sectional view of a main portion (especially, a portion indicated by a portion A surrounded by a dashed line in FIG. 5) to show the structure of a conveying means for the laminated ceramic capacitor shown in FIG. 5; . FIG. 6 is a time variation diagram of the voltage across the laminated ceramic capacitor according to the insulation resistance measuring method of the device for judging quality of the laminated ceramic capacitor shown in FIG. be. FIG. 9 is an explanatory diagram of a main part for specifically explaining the structure of the device for judging quality of a laminated ceramic capacitor according to the present invention shown in FIGS. 5, 6, 8, etc.; FIG. 5 is a time variation diagram of the voltage across the multilayer ceramic capacitor at the charging station and the charging/measuring station before insulation resistance measurement, and the multilayer ceramic according to the present invention shown in FIGS. 5, 6, 8, etc. FIG. 4 is an explanatory diagram of a main part showing the action and effect of the capacitor quality determination device; 1 is a model diagram showing an equivalent circuit of a laminated ceramic capacitor used in a device for judging quality of a laminated ceramic capacitor according to the present invention; FIG. FIG. 2 is an explanatory diagram of a principal part showing an example of a pass/fail judgment device of a comparative example for explaining the function and effect of the pass/fail judgment device for laminated ceramic capacitors according to the present invention; FIG. 12 is a time change diagram of the voltage across the multilayer ceramic capacitor according to the insulation resistance measuring method of the pass/fail judgment device of the comparative example shown in FIG. 11;

In the mode for carrying out the present invention, first, an example of a laminated ceramic capacitor to which the present invention can be applied will be described in detail below.
FIG. 1 is an external perspective view showing an example of a laminated ceramic capacitor according to the present invention. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, showing the multilayer ceramic capacitor according to the present invention. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1, showing a multilayer ceramic capacitor according to the present invention. FIG. 4(a) is a diagram showing a structure in which the counter electrode portion of the internal electrode layer of the laminate in the multilayer ceramic capacitor according to the present invention is divided into two. FIG. 4(b) is a diagram showing a structure in which the counter electrode portion of the internal electrode layer of the laminate in the multilayer ceramic capacitor according to the present invention is divided into three. FIG. 4(c) is a diagram showing a structure in which the counter electrode portion of the internal electrode layer of the laminate in the multilayer ceramic capacitor according to the present invention is divided into four.

As shown in FIGS. 1 to 4, a multilayer ceramic capacitor 10 includes a laminate 12 having a rectangular parallelepiped shape.

(Laminate 12)
The laminate 12 includes a plurality of laminated dielectric layers 14 and a plurality of internal electrode layers 16, and has a first main surface 12a and a second main surface 12b facing in the lamination direction x, and a main surface 12b facing in the lamination direction x. A first side face 12c and a second side face 12d facing each other in the orthogonal width direction y, and a first end face 12e and a second end face 12f facing each other in the length direction z orthogonal to the stacking direction x and the width direction y. ,including. Further, it is preferable that the laminate 12 has rounded corners and ridges. A corner portion is a portion where three adjacent surfaces of the laminate 12 intersect, and a ridge portion is a portion where two adjacent surfaces of the laminate 12 intersect. Furthermore, unevenness or the like is formed on a part or the whole of the first main surface 12a and the second main surface 12b, the first side surface 12c and the second side surface 12d, and the first end surface 12e and the second end surface 12f. may have been

The dimensions of the laminate 12 are such that the dimension L in the length direction z connecting the first end face 12e and the second end face 12f is 0.6 mm or more and 3.2 mm or less, and the first side face 12c and the second side face 12d is 0.3 mm or more and 2.5 mm or less in the width direction y, and the dimension T in the stacking direction x connecting the first main surface 12a and the second main surface 12b is 0.5 mm or more and 2.5 mm or less. is preferably

(Dielectric layer 14)
The laminate 12 includes an outer layer portion 14 a made up of a plurality of dielectric layers 14 and an inner layer portion 14 b made up of a plurality of dielectric layers 14 and a plurality of internal electrode layers 16 . The outer layer portion 14a is located on the side of the first main surface 12a and the second main surface 12b of the laminate 12, and is located between the first main surface 12a and the second main surface 12b and the first main surface 12a or the first main surface 12a. 2 is a dielectric layer 14 located between the internal electrode layer 16 close to the main surface 12b of the second substrate. A region sandwiched between the two outer layer portions 14a is the inner layer portion 14b.

As the ceramic material of the dielectric layer 14 of the laminate 12, for example, a dielectric ceramic composed mainly of BaTiO ₃ , CaTiO ₃ , SrTiO ₃ , CaZrO ₃ or the like can be used. In addition, subcomponents such as Mn compounds, Fe compounds, Cr compounds, Co compounds, and Ni compounds may be added to these main components.

The thickness of the dielectric layer 14 is preferably 0.7 μm or more and 4.0 μm or less. The number of dielectric layers is preferably 300 or more and 1200 or less including the outer layer portion 14a. The thickness of the outer layer portion 14a is preferably 50 μm or more and 200 μm or less.

(Internal electrode layer 16)
The internal electrode layers 16 are alternately laminated with a plurality of dielectric layers 14, and are alternately laminated with a plurality of first internal electrode layers 16a exposed on the first end surface 12e and with a plurality of dielectric layers 14. and a plurality of second internal electrode layers 16b exposed at two end faces 12f.

The first internal electrode layer 16a includes a first counter electrode portion 18a facing the second internal electrode layer 16b and a first electrode portion 18a extending from the first counter electrode portion 18a to the first end surface 12e of the laminate 12. 1 lead electrode portion 20a. The first lead-out electrode portion 20a of the first internal electrode layer 16a has an end portion led out to the surface of the first end surface 12e of the laminate 12 to form an exposed portion.

The second internal electrode layer 16b includes a second counter electrode portion 18b facing the first internal electrode layer 16a and a second electrode portion 18b extending from the second counter electrode portion 18b to the second end face 12f of the laminate 12. 2 lead-out electrode portions 20b. The second lead-out electrode portion 20b of the second internal electrode layer 16b has an end portion led out to the surface of the second end face 12f of the laminate 12 to form an exposed portion.

The counter electrode portion 18 is composed of a first counter electrode portion 18a of the first internal electrode layer 16a and a second counter electrode portion 18b of the second internal electrode layer 16b. Although the shapes of the first counter electrode portion 18a and the second counter electrode portion 18b are not particularly limited, they are preferably rectangular. However, the corner portions of the first counter electrode portion 18a and the second counter electrode portion 18b may be rounded or formed obliquely in a tapered shape, for example.

The extraction electrode portion 20 is composed of a first extraction electrode portion 20a of the first internal electrode layer 16a and a second extraction electrode portion 20b of the second internal electrode layer 16b. Although the shape of the first extraction electrode portion 20a and the second extraction electrode portion 20b is not particularly limited, it is preferably rectangular. However, the corners of the first extraction electrode portion 20a and the second extraction electrode portion 20b may be rounded or may be tapered and obliquely formed, for example.

The width of the first counter electrode portion 18a of the first internal electrode layer 16a and the second counter electrode portion 18b of the second internal electrode layer 16b, and the width of the first lead electrode portion 20a of the first internal electrode layer 16a The width of the second extraction electrode portion 20b of the second internal electrode layer 16b and the second lead electrode portion 20b may be the same, or one of them may be formed to have a narrower width.

In addition, the laminate 12 includes the first internal electrode layers 16a and the second internal electrode layers 16b, and the first counter electrode portions 18a and 18a where the first internal electrode layers 16a and the second internal electrode layers 16b face each other. The second counter electrode portion 18b, the side portion 22a ( W gap) and between the first and second counter electrode portions 18a and 18b and the first end face 12e and second end face 12f, and the first internal electrode layer 16a and the second internal electrode layer 16a and an end portion 22b (L gap) of the laminate 12 including the first lead-out electrode portion 20a and the second lead-out electrode portion 20b of either one of the internal electrode layers 16b.

Further, as shown in FIG. 4, the internal electrode layer 16 is provided with a floating internal electrode layer 16c that is not led out to either the first end surface 12e or the second end surface 12f. A structure in which the counter electrode portion 18 is divided into a plurality of parts may be employed. For example, there are a double structure (see FIG. 4(a)), a triple structure (see FIG. 4(b)), and a quadruple structure (see FIG. 4(c)). Needless to say, a structure of four or more units may be used. In this way, by dividing the counter electrode portion 18 into a plurality of pieces, a plurality of capacitor components are formed between the opposing internal electrode layers 16, and these capacitor components are connected in series. Therefore, the voltage applied to each capacitor component is lowered, and the multilayer ceramic capacitor 10 can be made to have a high withstand voltage.

The first internal electrode layers 16a and the second internal electrode layers 16b are made of, for example, metals such as Ni, Cu, Ag, Pd, and Au, and alloys containing at least one of these metals, such as Ag—Pd alloys. suitable conductive material.

In the present embodiment, the first counter electrode portion 18a and the second counter electrode portion 18b are opposed to each other with the dielectric layer 14 interposed therebetween, thereby forming a capacitance and exhibiting capacitor characteristics.

The thickness of each of the first internal electrode layers 16a and the second internal electrode layers 16b is preferably, for example, 0.2 μm or more and 2.0 μm or less. The number of internal electrode layers 16 is preferably 15 or more and 200 or less.

(External electrode 24)
The external electrode 24 is connected to the first internal electrode layer 16a, is connected to the first external electrode 24a arranged on the first end face 12e, and is connected to the second internal electrode layer 16b, is connected to the second end face 12f. and a second external electrode 24b disposed thereon. In addition, the first external electrode 24a and the second external electrode 24b are partially formed on the first main surface 12a and on the second main surface 12b, on the first side surface 12c and on the second main surface 12b. It is preferable that it is arranged so as to extend to a part of the second side surface 12d. It is preferable that the first external electrode 24a and the second external electrode 24b are formed to extend to at least a portion of the second main surface 12b located on the mounting surface side.

It is preferable that the first external electrode 24a and the second external electrode 24b have a base electrode layer 26 and a plating layer 28 .

The base electrode layer 26 has a first base electrode layer 26a and a second base electrode layer 26b. The underlying electrode layer 26 includes at least one selected from a baking layer, a conductive resin layer, a thin film layer, and the like.

The baking layer contains a glass component and a metal. The glass component of the baking layer contains at least one selected from B, Si, Ba, Mg, Al, Li and the like. The metal of the baking layer includes, for example, at least one selected from Cu, Ni, Ag, Pd, Ag--Pd alloy, Au and the like. The baking layer may be multiple layers.

The baking layer is obtained by applying a conductive paste containing glass and metal to the laminated body 12 and baking it. .

Thicknesses of the first baking layer and the second baking layer at the central portion in the stacking direction x of the first base electrode layer 26a and the second base electrode layer 26b located on the first end face 12e and the second end face 12f is, for example, preferably 15 μm or more and 160 μm or less. Further, when the base electrode layer 26 is provided on the first main surface 12a and the second main surface 12b, the first side surface 12c and the second side surface 12d, the first main surface 12a and the second main surface 12d are formed. The first baking layer and the second baking layer at the center in the length direction z, which are the first base electrode layer 26a and the second base electrode layer 26b located on the surface 12b, the first side surface 12c and the second side surface 12d. The thickness of the baked layer 2 is preferably, for example, 5 μm or more and 40 μm or less.

The conductive resin layer contains thermosetting resin and metal. The conductive resin layer may be multiple layers. The conductive resin layer may be arranged on the baking layer so as to cover the baking layer, or may be arranged directly on the laminate 12 .

As the thermosetting resin for the conductive resin layer, various known thermosetting resins such as epoxy resin, phenol resin, urethane resin, silicone resin, and polyimide resin can be used. Among them, epoxy resin is one of the most suitable resins because of its excellent heat resistance, moisture resistance, adhesion, and the like.

The thermosetting resin contained in the conductive resin layer is preferably contained at 25 vol % or more and 65 vol % or less with respect to the volume of the entire conductive resin.

Moreover, it is preferable that the conductive resin layer contains a curing agent together with the thermosetting resin. When an epoxy resin is used as the base resin, various known compounds such as phenol-based, amine-based, acid anhydride-based, and imidazole-based curing agents can be used as curing agents for the epoxy resin.

The metal contained in the conductive resin layer is mainly responsible for the electrical conductivity of the conductive resin layer. Specifically, contact between metals contained in the conductive resin layer forms an electric path inside the conductive resin layer.

The shape of the metal contained in the conductive resin layer is not particularly limited. The metal contained in the conductive resin layer may have a spherical shape or a flat shape, but it is preferable to use a mixture of spherical metal powder and flat metal powder. Moreover, the average particle size of the metal contained in the conductive resin layer is not particularly limited. The average particle size of the metal contained in the conductive resin layer may be, for example, 0.3 μm or more and 10 μm or less.

Ag, Cu, or alloys thereof can be used as the metal contained in the conductive resin layer. Also, metal powder whose surface is coated with Ag can be used. When using a metal powder whose surface is coated with Ag, it is preferable to use Cu or Ni as the metal powder. In addition, it is also possible to use Cu that has undergone an anti-oxidation treatment.

The reason why Ag conductive metal powder is used as the metal of the conductive resin layer is that Ag has the lowest specific resistance among metals and is therefore suitable as an electrode material. Because it is expensive. The reason for using the Ag-coated metal is that the base metal can be made inexpensive while maintaining the above characteristics of Ag.

The metal contained in the conductive resin layer is preferably contained in an amount of 35 vol % or more and 75 vol % or less with respect to the volume of the entire conductive resin.

The first conductive resin layer and the second conductive resin layer at the central portion in the stacking direction x of the first base electrode layer 26a and the second base electrode layer 26b located on the first end face 12e and the second end face 12f. The thickness of the resin layer is preferably, for example, 10 μm or more and 120 μm or less. Further, when the base electrode layer 26 is provided on the first main surface 12a and the second main surface 12b, the first side surface 12c and the second side surface 12d, the first main surface 12a and the second main surface 12d are formed. The first conductive resin layer at the center in the length direction z, which is the first base electrode layer 26a and the second base electrode layer 26b located on the surface 12b, the first side surface 12c and the second side surface 12d and the thickness of the second conductive resin layer is preferably, for example, 5 μm or more and 40 μm or less.

Since the conductive resin layer contains a thermosetting resin, it is more flexible than the base electrode layer 26 made of, for example, a plated film or a baked product of a conductive paste. Therefore, even if the multilayer ceramic capacitor 10 is subjected to physical impact or impact due to thermal cycles, the conductive resin layer functions as a buffer layer to prevent the multilayer ceramic capacitor 10 from cracking. can be done.

The thin film layer is formed by a thin film forming method such as a sputtering method or a vapor deposition method, and is a layer with a thickness of 1 μm or less on which metal particles are deposited.

(Plating layer 28)
The plating layer 28 has a first plating layer 28a and a second plating layer 28b. The first plating layer 28a is arranged to cover the first base electrode layer 26a. The second plating layer 28b is arranged to cover the second base electrode layer 26b.

The plated layer 28 contains, for example, at least one selected from Cu, Ni, Ag, Pd, Ag--Pd alloy, Au, and the like.

The plating layer 28 may be formed of multiple layers. A two-layer structure of a Ni-plated layer and a Sn-plated layer is preferred. The Ni plating layer can prevent the base electrode layer 26 from being eroded by solder when mounting the multilayer ceramic capacitor 10, and the Sn plating layer improves the wettability of the solder when mounting the multilayer ceramic capacitor 10. can be improved and easily implemented.

The thickness of each plated layer 28 is preferably 2 μm or more and 15 μm or less.

The external electrodes 24 may be formed only by the plating layer 28 without providing the base electrode layer 26 .
A structure in which the plating layer 28 is provided without providing the base electrode layer 26 will be described below.

Each of the first external electrode 24 a and the second external electrode 24 b may not be provided with the base electrode layer 26 and the plated layer 28 may be directly formed on the surface of the laminate 12 . That is, the laminated ceramic capacitor 10 may have a structure including the plated layers 28 electrically connected to the first internal electrode layers 16a or the second internal electrode layers 16b. In such a case, the plating layer 28 may be formed after disposing a catalyst on the surface of the laminate 12 as a pretreatment.

The plating layer 28 preferably includes a lower plating layer formed on the surface of the laminate 12 and an upper plating layer formed on the surface of the lower plating layer.

Each of the lower plated layer and the upper plated layer preferably contains at least one metal selected from, for example, Cu, Ni, Sn, Pb, Au, Ag, Pd, Bi or Zn, or an alloy containing the metal.

The lower plated layer is preferably formed using Ni, which has solder barrier properties, and the upper plated layer is preferably formed using Sn or Au, which has good solder wettability.

Further, for example, when the first internal electrode layers 16a and the second internal electrode layers 16b are formed using Ni, the lower plated layers are preferably formed using Cu, which has good bonding properties with Ni. . The upper plated layer may be formed as necessary, and each of the first external electrode 24a and the second external electrode 24b may be composed of only the lower plated layer.

The plating layer 28 may have an upper plating layer as the outermost layer, or may have another plating layer formed on the surface of the upper plating layer.

In the structure in which the plating layer 28 is provided without providing the base electrode layer 26, the thickness of each plating layer 28 is preferably 1 μm or more and 15 μm or less.

Plating layer 28 preferably does not contain glass. It is preferable that the metal ratio per unit volume of the plating layer 28 is 99% by volume or more.

The dimension in the length direction z of the multilayer ceramic capacitor 10 including the laminate 12 and the external electrodes 24 is defined as _LM dimension. The L _M dimension is preferably 0.6 mm or more and 3.2 mm or less. The dimension in the width direction y of the multilayer ceramic capacitor 10 including the laminate 12 and the external electrodes 24 is defined as _WM dimension. The W _M dimension is preferably 0.3 mm or more and 2.5 mm or less. The dimension in the stacking direction x of the multilayer ceramic capacitor 10 including the multilayer body 12 and the external electrodes 24 is defined as the T _M dimension. The T _M dimension is preferably 0.5 mm or more and 2.5 mm or less.

Next, an example of a device for judging quality of a laminated ceramic capacitor according to the present invention will be described below.
FIG. 5 is a plan view schematically showing an example of a device for judging quality of a laminated ceramic capacitor according to the present invention. FIG. 6 shows a cross-sectional view of the main part (particularly, the part indicated by the dashed-dotted line in FIG. 5) in order to show the structure of the conveying means for the laminated ceramic capacitor shown in FIG. It is an explanatory diagram.
As shown in FIG. 5, this laminated ceramic capacitor pass/fail determination apparatus (hereinafter simply referred to as "pass/fail determination apparatus") 30 includes, for example, a transport guide table 32 as transport guide means. The transport guide table 32 includes, for example, a circular rotor 34 in a plan view, and the rotor 34 is intermittently rotatable about its central axis 36 in, for example, the A direction shown in the drawing. Although the shape of the rotor 34 is not particularly limited, it is preferably circular in plan view. Further, although the rotor 34 is illustrated here as an example of the conveying guide means, any conveying means other than the rotor, such as an endless belt or a conveying pallet, may be used. Further, the driving form of the conveying guide means may be either intermittent driving or continuous driving.

The rotor 34 has, for example, three holding portion groups 38A, 38B and 38C arranged along the circumferential direction of the rotor 34 . The three holding portion groups 38A, 38B and 38C are arranged at equal intervals in the radial direction of the rotor 34. As shown in FIG.
One holding portion group 38A includes, for example, 24 holding portions 38a, 38a, 38a, . Similarly, the holding portion group 38B includes 24 holding portions 38b, 38b, 38b, . , 38c arranged at equal intervals along the circumferential direction of the rotor 34. As shown in FIG.
Each holding portion 38a of the holding portion group 38A, each holding portion 38b of the holding portion group 38B, and each holding portion 38c of the holding portion group 38C are arranged on the same radius of the rotor 34 at the same intervals. are arranged as follows.

Further, each of the holding portions 38a of the holding portion group 38A, each of the holding portions 38b of the holding portion group 38B, and each of the holding portions 38c of the holding portion group 38C has, for example, a holding hole 40 having a rectangular shape in plan view and a rectangular cross section (hereinafter referred to as , simply referred to as "cavity 40"). The cavity 40 is a through hole penetrating the upper surface (one main surface) and the lower surface (the other main surface) of the rotor 34, and the shape and size of the cavity 40 are determined according to the shape and size of the multilayer ceramic capacitor 10. , can be arbitrarily changed as appropriate.

On the other hand, on the back surface of the rotor 34, for example, suction grooves are processed, and air is sucked from a characteristic selector (not shown) arranged under the rotor 34, for example, the lamination shown in FIGS. The ceramic capacitors 10 are held one by one in the cavity 40 by suction. In this case, the external electrodes 24 of the multilayer ceramic capacitor 10 are accommodated so as to face the upper surface and the lower surface (both main surfaces) of the rotor 34 . That is, the multilayer ceramic capacitor 10 is arranged in the cavity 40 of the rotor 34 so that the one external electrode 24a and the other external electrode 24b are exposed to the upper surface and the lower surface of the rotor 34, respectively.
A uniaxial motor (not shown), for example, is attached to the central shaft 36 of the rotor 34 . The rotor 34 rotates one step at a time for each cavity 40, and intermittently conveys the multilayer ceramic capacitor 10 in the direction A as shown in FIG.

The rotor 34 has a plurality of charging stations 50 and 52 and a charging/measuring station 60 spaced apart along the circumference of the rotor 34, as shown in FIG. At charging stations 50 and 52, multilayer ceramic capacitors 10 (hereinafter also simply referred to as "workpieces 10") are charged, and at charging/measuring station 60, charging and measurement are performed.

As shown in FIGS. 6 and 7, each of the plurality of charging stations 50 and 52 has, for example, two probes 70a and 70b (not shown in FIG. 5) that move up and down with respect to the external electrodes 24a and 24b of the workpiece 10. provided as possible. As the rotor 34 rotates, the cavity 40 holding the workpiece 10 is conveyed to the charging station 50, and when the workpiece 10 stops, the two probes 70a and 70b are connected to the external electrodes 24a and 24b of the workpiece 10. is brought into contact with the work 10 to charge the work 10 . Two probes 70a, 70b are used as charging terminals.
Although the shape of the probes 70a and 70b is not particularly limited, for example, a roller shape, a cylindrical shape using a spring on the outside, or the like can be used as appropriate. Also, the material of the probes 70a and 70b is not particularly limited as long as it is chargeable.

For example, as shown in FIG. 8, the pass/fail determination device 30 can continuously charge a plurality of laminated ceramic capacitors 10 with a DC voltage equal to or higher than the rated voltage of the laminated ceramic capacitors 10 by means of an application circuit 80. It's becoming Although the DC voltage is not particularly limited, it is preferably several times or more the rated voltage of the laminated ceramic capacitor 10 . This application circuit 80 is connected to the positive electrode side of a power supply (E) 82, the external electrode 24b of the workpiece 10 conveyed to the charging station 52, and the external electrode 24b of the workpiece 10 conveyed to the charging/measuring station 60. It is connected between the probes 70b and 72b that are in contact with each other to turn ON/OFF the voltage application, and also controls the current value to supply a certain amount of current (for example, 50 mA or less) to the multilayer ceramic capacitor 10. is applied to

Further, in this pass/fail judgment apparatus 30, the negative electrode of the power supply (E) 82, the external electrode 24a of the work 10 conveyed to the charging station 52, and the outside of the work 10 conveyed to the charging/measuring station 60 are connected. Probes 70a and 72a that contact electrode 24a are connected. Further, between the negative electrode side of the power supply (E) 82 and the probe 72a that contacts the external electrode 24a of the workpiece 10 conveyed to the charging/measuring station 60, an IR electrode for measuring insulation resistance is provided. A meter 84 is connected.

Further, in this pass/fail judgment device 30, as shown in FIG. 8, it is connected to an application circuit 80, for example, a resistor 86 (R). The resistor 86 (R) has one end connected to the application circuit 80 and the other end grounded to the ground point GND. For example, as shown in FIG. 9, the circuit including this resistor 86 (R) changes the charge of the work 10 to the applied voltage after the work 10 conveyed to the charging station 52 is charged. As a discharge circuit that discharges electric charge within a predetermined range, it has a function of discharging the electric charge of the workpiece 10 once charged.
In this discharging circuit, it is preferable to discharge the charge of the laminated ceramic capacitor 10 after charging within a range of 50% or more and 70% or less of the applied voltage. The amount of discharge at this time is appropriately controlled by the value of the resistor 86 (R).

Further, as shown in FIG. 8, the pass/fail determination device 30 is used as a charging terminal for charging the work 10 transported to the charging/measuring station 60, and Probes 72a and 72b used as terminals for measuring the insulation resistance of the workpiece 10 (for example, the insulation resistance IR shown in FIG. 10) are provided. These probes 72a and 72b are used, for example, as charging terminals used in the charging stations 50 and 52 described above, and are formed of the same shape and material as the probes 70a and 70b.

A switch 88 (SW) is connected between the probe 72b, which contacts the external electrode 24b of the multilayer ceramic capacitor 10 conveyed to the charging/measuring station 60, and the ground point GND. After measuring the insulation resistance of the workpiece 10 conveyed to the charging/measuring station 60, the switch 88 (SW) is turned on, and the external electrode 24b of the workpiece 10 is grounded via the switch 88 (SW). Grounded to GND. Therefore, the charges accumulated in the work 10 are discharged.

Next, an example of a method for judging the quality of a laminated ceramic capacitor using the apparatus 30 for judging the quality of a laminated ceramic capacitor will be described below.
First, for example, the multilayer ceramic capacitor 10 shown in FIGS. They are sucked and held one by one.
Next, by rotating the rotor 34, the rotor 34 rotates for each cavity 40, and the work 10 is intermittently conveyed in the A direction as shown in FIG.
Then, when a plurality of works 10 are conveyed to the charging station 50 and the works 10 stop, the two probes 70a and 70b contact the external electrodes 24a and 24b of the work 10, and the work 10 is charging. In this case, a DC voltage several times the rated voltage of the multilayer ceramic capacitor 10 is continuously charged for a certain period of time.
Furthermore, the work 10 is transported to the next charging station 52, and the work 10 is charged in the same manner.

In this pass/fail judgment apparatus 30, as shown in FIGS. 7 and 9, in the charging station 52 immediately before the charging/measuring station 60, the charge of the workpiece 10 after being charged is temporarily reduced to a predetermined range with respect to the applied voltage. , and then charge the workpiece 10 with a DC voltage equal to or higher than the rated voltage, and then measure the insulation resistance.
That is, in charging station 52 immediately before charging/measuring station 60, probe 70b is short-circuited to resistor 86(R) and ground point GND as shown in FIG. Thus, a predetermined amount of discharge is performed immediately before the workpiece 10 is transported to the charging/measuring station 60 . In this case, the amount of discharge is preferably in the range of 50% or more and 70% or less of the applied voltage.
As a result, by discharging a small amount of electric charge in the workpiece 10, for example, as shown in FIG. 7 and FIG. It is possible to lower the potential difference (PD) between

In this pass/fail judgment device 30, if the resistor 86 (R) is not provided, for example, as shown in FIGS. Since the potential difference between the probes 72a and 72b as terminals for measuring the insulation resistance increases, a large spark is generated. As shown in FIGS. 7 and 9, a smaller potential difference (PD) can be used to suppress such sparks.

The workpiece 10 discharged by a predetermined amount at the charging station 52 is further transported to the charging/measuring station 60 . In the workpiece 10 transported to the charging/measuring station 60, the probes 72a and 72b are brought into contact with the external electrodes 24a and 24b of the workpiece 10, respectively, as shown in FIG. On the other hand, a DC voltage several times the rated voltage is charged. The insulation resistance of the workpiece 10 is then measured. In this case, the leakage current from the workpiece 10 is detected by the IR meter 84, and the insulation resistance IR is measured. After that, the voltage of the workpiece 10 is discharged to zero volts. If the insulation resistance IR exceeds the lower limit of the threshold of the processing conditions, it is determined as a non-defective product, and if it is within the lower limit of the threshold, it is determined as a defective product.

In the device for judging quality of a laminated ceramic capacitor according to the present invention and the laminated ceramic capacitor using the same, the circuit for discharge can also use a semiconductor element, for example, in addition to the resistor 86 (R). It is also possible to use an electronic load device using resistors and semiconductor elements as the discharge circuit.

With the above configuration, in the device for judging quality of a multilayer ceramic capacitor according to the present invention and the multilayer ceramic capacitor using the same, the charging station 52 immediately before the charging/measuring station 60 controls the inside of the multilayer ceramic capacitor 10. By discharging a small amount of electric charge, it is possible to reduce the potential difference (PD) between the probes 72a and 72b, which are terminals for charging and measuring, and the multilayer ceramic capacitor 10 when the probes 72a and 72b are brought into contact with each other. . Therefore, in the pass/fail judgment of a laminated ceramic capacitor using this pass/fail judging device 30, when measuring the insulation resistance of the laminated ceramic capacitor, the energy of the spark generated between the measurement terminals and the laminated ceramic capacitor can be suppressed. Noise generated by sparks can be suppressed.
That is, the energy of sparks generated between the probes 72a and 72b and the multilayer ceramic capacitor 10 can be suppressed. Therefore, noise generated by sparks can cause, for example, communication troubles between the control computer of the measuring equipment and the IR meter, making it impossible to measure the insulation resistance and stopping the equipment. becomes possible.

In addition, it is possible that a small amount of electric charge in the charged multilayer ceramic capacitor is discharged, which causes a decrease in insulation resistance at regular intervals, making it impossible to measure the correct insulation resistance value (IR value). Although the charge on the component is discharged, the charge remains in the dielectric absorption factor D, as shown for example in FIG. is considered to have been reached. The inventor believes that there is no significant difference in the IR values from the actually measured data.

REFERENCE SIGNS LIST 10 multilayer ceramic capacitor 12 laminate 12a first main surface 12b second main surface 12c first side surface 12d second side surface 12e first end surface 12f second end surface 14 dielectric layer 14a outer layer portion 14b inner layer portion 16 Internal electrode layer 16a First internal electrode layer 16b Second internal electrode layer 16c Floating internal electrode layer 18 Counter electrode portion 18a First counter electrode portion 18b Second counter electrode portion 20 Extraction electrode portion 20a First extraction electrode Part 20b Second extraction electrode part 22a Side part (W gap)
22b end (L gap)
24 external electrode 24a first external electrode 24b second external electrode 26 base electrode layer 26a first base electrode layer 26b second base electrode layer 28 plating layer 28a first plating layer 28b second plating layer

30 Apparatus for judging quality of laminated ceramic capacitor 32 Transfer guide table (transfer guide means)
34 Rotor 36 Central axis of rotor 38A, 38B, 38C Holding portion group 38a, 38b, 38c Holding portion 40 Storage hole (cavity)
50, 52 charging station 60 charging/measuring station 70a, 70b probes (terminals for charging)
72a, 72b other probes (terminals for charging/measurement)
80 application circuit 82 power supply (E)
84 IR meter 86 Resistance (R)
88 switch (SW)

C Main capacitance ESR Equivalent series resistance ESL Equivalent series inductance IR Insulation resistance D Dielectric absorption factor _C0 Dielectric polarization capacity _R0 Internal resistance SW Switch GND Ground point PD Potential difference

x Lamination direction y Width direction z Length direction L Length in the length direction of the laminate W Length in the width direction of the laminate T Length in the lamination direction of the laminate L _M Length in the length direction of the multilayer ceramic electronic component _WM Length in the width direction of the multilayer ceramic electronic component T _M Length in the lamination direction of the multilayer ceramic electronic component

Claims (4)

A transport for holding and transporting a plurality of multilayer ceramic capacitors having a laminate having a plurality of laminated dielectric layers and a plurality of laminated internal electrode layers, and external electrodes connected to the plurality of internal electrodes. means and
an applying circuit and a charging terminal for continuously charging a DC voltage equal to or higher than the rated voltage of the multilayer ceramic capacitors to the plurality of multilayer ceramic capacitors;
a discharging circuit for discharging the charge of the laminated ceramic capacitor after charging within a predetermined range with respect to the applied voltage;
a measuring terminal for measuring the insulation resistance of the laminated ceramic capacitor after discharging;
A device for determining the quality of a multilayer ceramic capacitor,
The application circuit continuously charges the plurality of laminated ceramic capacitors with a DC voltage equal to or higher than the rated voltage of the laminated ceramic capacitors for a certain period of time,
By the discharging circuit, the charge of the laminated ceramic capacitor after charging is once discharged within a predetermined range with respect to the applied voltage,
contacting the measuring terminal with the external electrode for the laminated ceramic capacitor after discharging;
After the measurement terminal is brought into contact with the external electrode, the multilayer ceramic capacitor is again charged with a DC voltage equal to or higher than the rated voltage of the multilayer ceramic capacitor by the application circuit, and then the insulation resistance is measured to measure the multilayer ceramic capacitor. A multi-layer ceramic capacitor pass/fail judgment device for judging pass/fail. 2. The device for judging quality of a laminated ceramic capacitor according to claim 1, wherein said conveying means includes a rotor. 3. The device for judging quality of a laminated ceramic capacitor according to claim 1, wherein said discharge circuit includes a resistor. 2. The quality of the multilayer ceramic capacitor according to claim 1, wherein the discharge resistor that discharges the charge within a predetermined range with respect to the applied voltage discharges the charge within a range of 50% or more and 70% or less with respect to the applied voltage. judgment device.

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