JP2012094671A - Electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic component capable of improving the effect of suppressing vibration noise generated on a substrate.SOLUTION: A ceramic capacitor 10 of the present invention includes a ceramic capacitor element 11 and a pair of connection terminals 12. The ceramic capacitor element 11 comprises: a dielectric assembly 21 having a plurality of dielectric layers 26 and a plurality of internal electrodes 27; and external electrodes 22 provided on respective end faces 23a and 23b of the dielectric assembly 21. Each of the connection terminals 12 comprises: an electrode connection part 41 connected to each of the external electrodes 22; an external connection part 42 which is connected to a substrate 13 and is arranged to face the dielectric assembly 21; and an intermediate part 43 which connects the electrode connection part 41 to the external connection part 42 in such a manner that a gap is formed between a lower face (lateral face 24b) of the dielectric assembly 21 and the external connection part 42. Each connection terminal 12 is made of a porous metal plate. The average porosity of the connection terminals 12 is higher than 30% but not higher than 80%, and the average pore diameter is greater than 1 μm but not greater than 30 μm.

Description

  The present invention relates to an electronic component mounted on a circuit board, and is particularly suitable for a multilayer ceramic capacitor.

  In various types of portable information processing devices such as notebook personal computers, PDAs (Personal Digital Assistants), and mobile phones, capacitors, inductors, varistors, or composite components that combine these are mounted on the circuit board as electronic components. The size of the entire circuit board is reduced by mounting electronic components at high density. A multilayer ceramic capacitor is used as a capacitor mounted on such a circuit board.

  In the multilayer ceramic capacitor, dielectrics and internal electrodes are alternately stacked. Ferroelectric materials such as barium titanate having a relatively high dielectric constant are generally used for the ceramic material forming the dielectric. When an AC voltage is applied to such a multilayer ceramic capacitor, the ceramic material that forms the dielectric is accompanied by electrostriction, so the thickness of each dielectric layer changes according to the voltage change, and the size of the ceramic capacitor Changes. As a result, the ceramic capacitor causes mechanical distortion corresponding to the magnitude of the applied voltage. For this reason, when an AC voltage is applied to the ceramic capacitor, the ceramic capacitor vibrates due to the electrostriction phenomenon of the dielectric.

  The vibration of the ceramic capacitor due to the electrostriction phenomenon propagates to the substrate on which the ceramic capacitor is mounted. By the vibration transmitted to the substrate, the substrate resonates and the vibration is amplified, and vibration sound (sound) is generated in the substrate. That is, the ambient air vibrates due to the vibration of the capacitor to generate sound, and the vibration transmitted to the substrate also causes the substrate to resonate and generate sound. When the sound pressure generated due to the vibration of the capacitor increases, the vibration sound is recognized by the human ear as an audible sound.

  Further, the vibration of the ceramic capacitor tends to increase the vibration sound transmitted to the substrate and increase the vibration sound of the substrate as the ceramic material having a large number of dielectrics and a large electrostriction is used. In particular, in order to obtain a larger capacitance, when a plurality of ceramic capacitors are connected in parallel on the substrate, etc., because the plurality of ceramic capacitors vibrate at the same period, the vibration transmitted to the substrate is amplified. Vibration noise is more likely to occur.

  Therefore, in order to reduce the vibration noise of the substrate, a multilayer ceramic capacitor in which a pair of connection terminals is provided in contact with the terminal electrode of the ceramic capacitor element has been proposed (for example, see Patent Documents 1 and 2). According to the multilayer ceramic capacitors described in Patent Documents 1 and 2, the metal terminals are surface-mounted on the substrate by floating the ceramic capacitor elements from the substrate, and the electrode connection portions of the pair of connection terminals and the terminal electrodes of the ceramic capacitor elements By providing a structure with a gap between them, the vibration generated in the ceramic capacitor element is suppressed from propagating to the substrate, and the generation of the vibration noise caused by the ceramic capacitor is suppressed.

JP 2004-153121 A JP 2005-64377 A

  However, like a conventional multilayer ceramic capacitor, the metal plate itself used as the connection terminal is hard and highly elastic. Therefore, the vibration generated in the ceramic capacitor element cannot be sufficiently absorbed by the metal plate only by bending and molding the metal plate. Therefore, there is a problem that the vibration propagating to the substrate cannot be sufficiently suppressed and the effect of suppressing the vibration sound generated on the substrate is small.

  The present invention has been made in view of the above, and an object of the present invention is to provide an electronic component that can improve the effect of suppressing vibration noise generated in a substrate.

  In order to solve the above-described problems and achieve the object, the present inventors have intensively studied electronic components. As a result, the connection terminal that connects the element and the substrate is formed of a porous material, and the average porosity and the average pore diameter are within a predetermined range, so that vibration generated in the element is propagated to the substrate. It has been found that the effect of suppressing vibration noise generated due to the element can be efficiently improved and the effect of suppressing the vibration sound can be improved. The present invention has been completed based on such knowledge.

  An electronic component of the present invention is an element having a dielectric element body having a plurality of dielectric layers and an internal electrode provided via the dielectric layer, and an external electrode provided on an end face of the dielectric element layer And a pair of connection terminals, wherein the connection terminals are connected to the external electrodes, connected to a substrate and provided to face the dielectric element body, and An intermediate portion for connecting the electrode connection portion and the external connection portion so as to have a gap between the lower surface of the dielectric element body and the external connection portion, and is formed using a porous metal plate. The connection terminals have an average porosity of 30% to 80% and an average pore diameter of 1 μm to 30 μm.

  According to this configuration, a porous metal plate is used as the connection terminal, and the average porosity and average pore diameter of the metal plate are within the above ranges, thereby suppressing the vibration generated in the element from propagating to the substrate. Therefore, the effect of suppressing vibration noise generated from the substrate due to the element can be improved.

  According to the present invention, it is possible to improve the effect of suppressing vibration noise generated in the substrate.

FIG. 1 is a perspective view of a ceramic capacitor according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is an explanatory diagram showing dimensions of the connection terminals. FIG. 4 is a partial cross-sectional view schematically showing a part of the intermediate portion of the connection terminal. FIG. 5 is an explanatory diagram showing the volume occupied by the connection terminal when the volume occupied by the pores is removed from the connection terminal. FIG. 6 is a diagram simply showing the configuration of the test apparatus used when measuring the sound pressure.

  DESCRIPTION OF EMBODIMENTS Hereinafter, modes for suitably carrying out the present invention (hereinafter referred to as embodiments) will be described in detail. In addition, this invention is not limited by the content described in the following embodiment and an Example. In addition, constituent elements in the embodiments and examples described below include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the embodiments and examples described below may be appropriately combined or may be appropriately selected and used.

  1 and 2 show a preferred embodiment of a ceramic capacitor which is an electronic component according to an embodiment of the present invention. FIG. 1 is a perspective view of a ceramic capacitor according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA in FIG. As shown in FIGS. 1 and 2, the ceramic capacitor 10 includes a ceramic capacitor element 11 and a pair of connection terminals 12. In the present embodiment, the length direction of the ceramic capacitor element 11 in FIG. 1 is X, the width direction is Y, and the thickness direction is Z.

  The ceramic capacitor 10 is mounted on a circuit board (hereinafter referred to as “substrate”) 13. Although the ceramic capacitor 10 is configured by one ceramic capacitor element 11, the present embodiment is not limited to this, and the ceramic capacitor 10 may be formed by stacking a plurality of ceramic capacitor elements 11.

  The substrate 13 is used in a small processing apparatus such as a notebook personal computer, a PDA, or a mobile phone. Substrate electrodes 14A and 14B are provided on the surface of the substrate 13 on which the ceramic capacitor 10 is mounted. Wirings 15A and 15B extend from the substrate electrodes 14A and 14B. The pair of connection terminals 12 are soldered to the substrate electrodes 14A and 14B by solder 16, respectively.

  The ceramic capacitor element 11 includes a dielectric element body 21 and a pair of terminal electrodes (external electrodes) 22 respectively formed at both ends of the dielectric element body 21. The ceramic capacitor element 11 is a multilayer ceramic capacitor, and is formed in a substantially rectangular parallelepiped shape having both side surfaces and four side surfaces including an upper surface, a lower surface, and both side surfaces.

  In the present embodiment, the “substantially rectangular parallelepiped shape” means not only a cubic shape or a rectangular parallelepiped shape, but also a ridge line portion of the rectangular parallelepiped is chamfered as in the dielectric element body 21, and the ridge portion has an R shape. Needless to say, the shape is included. By making the dielectric element body 21 into an R shape, it is possible to suppress the occurrence of damage at the ridges of the dielectric element body 21. That is, the dielectric element body 21 only needs to have a substantially cubic shape or a rectangular parallelepiped shape.

  The dielectric element body 21 includes an end face 23a and an end face 23b (hereinafter, collectively referred to as “end face 23”) that face each other, and a side face 24a and a side face 24b that are perpendicular to the end face 23 and face each other (hereinafter collectively). The side surface 24a and the side surface 24b may be referred to as an “upper surface” and a “lower surface” respectively. And may be collectively referred to as “side surface 25”). The side surface 24 and the side surface 25 are perpendicular to each other.

  The dielectric body 21 has a plurality of dielectric layers 26 and a plurality (for example, about 100 layers) of internal electrodes 27. The dielectric body 21 is formed by alternately laminating a plurality of dielectric layers 26 and a plurality of internal electrodes 27. The dielectric element body 21 is formed by laminating a plurality of ceramic green sheets (unfired ceramic sheets), and integrally laminating a laminate including a predetermined pattern of conductive paste that becomes the internal electrode 27 between the ceramic green sheets. Thus, it is a substantially rectangular parallelepiped sintered body obtained by cutting, degreasing and firing. The stacking direction of the dielectric layer 26 and the internal electrode 27 is the thickness direction Z of the ceramic capacitor element 11. The dielectric element body 21 is formed in a rectangular parallelepiped shape having both side surfaces and four side surfaces including an upper surface, a lower surface, and both side surfaces, and the size of the dielectric element body 21 is, for example, the length direction X The width direction Y and the thickness direction Z are approximately 3.2 mm, 2.5 mm, and 2.5 mm, respectively. For convenience of explanation, in FIG. 2, the number of stacked layers of the dielectric layers 26 and the internal electrodes 27 is set so as to be visible. However, depending on the desired electrical characteristics, the stacked layers of the dielectric layers 26 and the internal electrodes 27. The number may be changed as appropriate. The number of stacked layers may be, for example, several tens of layers of the dielectric layer 26 and the internal electrode 27, or about 100 to 500 layers. Further, the actual dielectric element body 21 may be integrated so that the interlayer of the dielectric layer 26 cannot be visually recognized.

The dielectric layer 26 is obtained by firing a ceramic green sheet. The dielectric material constituting the dielectric layer 26 is not particularly limited, and examples thereof include calcium titanate, strontium titanate, and barium titanate (BaTiO ₃ ). The dielectric layer 26 may be used by mixing one or more of these dielectric materials. The dielectric layer 26 is particularly preferably composed of BaTiO ₃ as a ferroelectric material having a high dielectric constant from the viewpoint of having a high dielectric constant. The dielectric element body 21 composed of barium titanate or the like as the main component as the dielectric layer 26 has a function as a dielectric substance, and is distorted when an electric field is applied. For this reason, when an AC voltage is applied to the ceramic capacitor element 11, a mechanical strain corresponding to the magnitude of the AC voltage is generated, and this mechanical strain is vibrated and propagates to the substrate 13. Vibrate and the vibration is in the audible frequency band, the vibration of the substrate 13 appears as a vibration sound.

  One end of the internal electrode 27 is exposed from one of the end faces 23 a and 23 b of the dielectric element body 21, is connected to one external electrode 22, and the other end is an open end. Insulated. Internal electrodes 27 respectively connected to a pair of opposing external electrodes 22 are alternately opposed to each other via a dielectric layer 26, and a plurality of layers are stacked at a predetermined interval.

  As a material constituting the internal electrode 27, any conductive material that is usually used as an internal electrode of a multilayer ceramic electronic component can be used. For example, a conductive material mainly composed of Pd, Ag, and Ni is used. Things that are included are used.

  The external electrode 22 is provided so as to cover the end faces 23 a and 23 b of the dielectric element body 21 and a part of the side faces 24 and 25 on the end faces 23 a and 23 b side. The external electrode 22 is connected to the internal electrode 27 at the end faces 23 a and 23 b of the dielectric element body 21. The external electrode 22 can be used as long as it is a conductive material usually used as an external electrode of an electronic component. For example, a material containing Cu as a main component is used. The external electrode 22 is formed by applying and baking a conductive paste containing Cu powder on the end faces 23 a and 23 b of the dielectric element body 21. As a metal component constituting the external electrode 22, in addition to Cu, Ag, Pd, Ni, Sn, or the like may be included as a conductive material. The external electrode 22 may be composed of a plurality of metal electrode layers. For example, a Ni plating layer and a Sn plating layer may be formed on a base electrode mainly composed of Cu.

  In the ceramic capacitor 10, charges are accumulated in the ceramic capacitor element 11 by applying a voltage to the pair of external electrodes 22 of the ceramic capacitor element 11.

  A pair of connection terminals 12 are provided so as to connect the substrate electrodes 14A and 14B and the pair of external electrodes 22, respectively. The connection terminal 12 is connected to a pair of external electrodes 22 by soldering with a solder 28.

  Examples of the metal plate used to form the connection terminal 12 include metals such as titanium, nickel, aluminum, and copper, and alloys containing these metals, such as titanium alloys, copper alloys, and alloys such as stainless steel. However, the present invention is not limited to this.

  In the present embodiment, the connection terminal 12 is made of a metal member and includes an electrode connection portion 41, an external connection portion 42, and an intermediate portion 43. Specifically, the electrode connection portion 41 is connected to the external electrode 22 on the end faces 23 a and 23 b side of the dielectric element body 21 in the length direction X of the ceramic capacitor element 11. The external connection portion 42 is provided on the substrate electrodes 14A and 14B so as to face the dielectric element body 21, and is connected to the substrate electrodes 14A and 14B by the solder 16. The intermediate portion 43 is provided between the electrode connection portion 41 and the external connection portion 42 so as to have a gap between the lower surface (side surface 24 b) of the dielectric element body 21 and the substrate 13. As shown in FIGS. 1 and 2, the connection terminal 12 is provided with the dielectric body 21 so as to have a gap between the external connection portion 42 and the lower surface (side surface 24 b) of the dielectric body 21. It is formed to be bent in an L shape on the side where it is present.

  When a voltage is applied to the pair of external electrodes 22 of the ceramic capacitor element 11, vibration is generated in the dielectric element body 21, but transmission of vibration generated in the dielectric element body 21 to the substrate 13 is suppressed. For this purpose, it is necessary to suppress the vibration generated in the dielectric body 21 at the connection terminal 12 from being transmitted to the substrate 13. In order to suppress the vibration generated in the dielectric body 21 at the connection terminal 12 from being transmitted to the substrate 13, it is necessary to reduce the spring constant K of the connection terminal 12.

  FIG. 3 is an explanatory diagram showing dimensions of the connection terminals. The connection terminal shown in FIG. 3 is a general connection terminal conventionally used. In FIG. 3, the thickness of the connection terminal 31 is t, the width is b, and the distance from the substrate electrode 33 of the substrate 32 to the substrate surface 34 side of the solder 28 that connects the connection terminal 31 and the external electrode 22 of the ceramic capacitor element 11. Let (connecting terminal mounting length) be L. At this time, the spring constant K of the connection terminal 31 can be expressed by the following formula (1). E in the following formula (1) is the Young's modulus of the connection terminal 31.

  As the spring constant K of the connection terminal 31 is smaller, the vibration generated due to the electrostriction of the dielectric element body 21 is suppressed from being transmitted to the substrate 32, and the effect of suppressing the generation of vibration noise is increased. Can do. Since the connection terminal 31 is for electrically connecting the external electrode 22 of the ceramic capacitor element 11 and the substrate electrode 33 of the substrate 32, it needs to be conductive. Although there is a metal material as a material having conductivity, the metal material generally has a high Young's modulus. For this reason, there is a limit in reducing the spring constant K of the connection terminal 31 only by bending and molding a plate-shaped metal material.

  In the present embodiment, the connection terminal 12 is formed using a porous metal plate. FIG. 4 is a partial cross-sectional view schematically showing a part of the intermediate portion 43 of the connection terminal 12. As shown in FIG. 4, the connection terminal 12 has a plurality of pores 44 having different pore diameters. The average porosity of the connection terminal 12 is 30% or more and 80% or less, preferably 50% or more and 78% or less, and more preferably 50% or more and 70% or less. By setting the average porosity of the connection terminal 12 to 30% or more, an effect of absorbing vibration generated in the ceramic capacitor 10 can be obtained. Further, by setting the average porosity of the connection terminal 12 to 80% or less, it is possible to maintain sufficient strength to hold the ceramic capacitor element 11 and to maintain sufficient wettability with the solder 16. . Therefore, by setting the average porosity of the connection terminal 12 within the above range, it is possible to obtain a sufficient effect of holding the ceramic capacitor element 11 while obtaining the effect of absorbing the vibration generated in the dielectric element body 21. it can. The porosity is the ratio of the pore area in the cross-sectional area of the metal plate, and the average porosity is the average porosity in the plurality of cross-sectional areas of the metal plate.

  The average pore diameter of the connection terminal 12 is 1 μm or more and 30 μm or less, preferably 5 μm or more and 30 μm or less, and more preferably 10 μm or more and 30 μm or less. By setting the average pore diameter of the connection terminal 12 to 1 μm or more, it is possible to suppress the solder 16 from ascending the connection terminal 12 due to a capillary phenomenon, so that it is possible to sufficiently obtain the effect of absorbing vibration generated in the ceramic capacitor 10. it can. Further, by setting the average pore diameter of the connection terminal 12 to 30 μm or less, the strength sufficient to hold the ceramic capacitor 10 can be maintained, and the wettability with the solder 16 can be sufficiently maintained. Therefore, by setting the average pore diameter of the connection terminal 12 within the above range, the strength sufficient to hold the ceramic capacitor 10 can be maintained while obtaining the effect of absorbing the vibration generated in the ceramic capacitor 10. The pore diameter is the inner diameter of each pore that appears as a cross-sectional area, and the average pore diameter refers to the average inner diameter of each pore that appears as a cross-sectional area.

  By setting the average porosity and the average pore diameter of the connection terminal 12 within the above ranges, the connection terminal 12 can substantially reduce the thickness t or the width b in the above formula (1). The spring constant K can be reduced. FIG. 5 is an explanatory diagram showing the volume occupied by the connection terminal 12 when the volume occupied by the pores 44 is removed from the connection terminal 12. As shown in FIG. 5, when the length L and width b of the connection terminal 12 are constant, the volume actually occupied by the thickness t of the connection terminal 12 when the volume of the pores 44 is excluded is the thickness t. Thus, the volume actually occupied by the thickness t of the connection terminal 12 when the volume occupied by the pores 44 is excluded becomes relatively small. Therefore, the volume actually occupied by the connection terminal 12 is a product of the length L, the width b, and the thickness t ′ of the connection terminal 12. For this reason, when the vibration generated in the dielectric body 21 is propagated from the ceramic capacitor element 11 to the substrate 13, the vibration generated in the dielectric body 21 is absorbed in the connection terminal 12, thereby the dielectric body body. It is possible to suppress the vibration generated in 21 from propagating to the substrate 13. By suppressing the vibration generated in the dielectric body 21 from being propagated to the substrate 13, the vibration sound generated in the substrate 13 can be suppressed. Note that the magnitude of the vibration sound is obtained from the sound pressure measured through, for example, a sound collecting microphone described later.

  Although the connection terminal 12 is a porous plate having a plurality of pores, the wettability of the solder 16 with respect to the connection terminal 12 is sufficiently maintained by setting the average porosity and the average pore diameter of the connection terminal 12 within the above ranges. The connection terminal 12 can be fixed to the substrate electrodes 14A and 14B with the solder 16 and can be stably connected. Also, by plating the surface of the connection terminal 12 with, for example, an alloy of Ni and Sn, the wettability with the solder 16 can be ensured as before, and the connection terminal 12 is fixed to the substrate electrodes 14A and 14B with the solder 16 and stable. Can be connected.

  As described above, the porous metal plate used to form the connection terminal 12 is a metal such as titanium, nickel, aluminum, copper, or an alloy containing these metals, such as a titanium alloy, a copper alloy, Alloys such as stainless steel can be used, but the average porosity and the average pore diameter of the connection terminal 12 are within the above ranges, and the connection terminal 12 is particularly limited to this as long as the spring constant K of the connection terminal 12 can be reduced. is not.

  The external electrode 22 of the ceramic capacitor element 11 and the electrode connection portion 41 of the connection terminal 12 are connected by soldering with a solder 28, but this embodiment is not limited to this, and conductive bonding You may make it connect the external electrode 22 and the electrode connection part 41 of the connecting terminal 12 using an agent. By connecting the external electrode 22 and the connection terminal 12 with the solder 28 or the conductive adhesive, it is possible to stably connect while ensuring the electrical conductivity between the external electrode 22 and the connection terminal 12. For this reason, even if the external electrode 22 of the ceramic capacitor element 11 and the electrode connection portion 41 of the connection terminal 12 are connected by the solder 28 or the conductive adhesive, the vibration generated in the ceramic capacitor element 11 is caused by the connection terminal 12. It is possible to stably suppress the propagation of vibrations to the substrate 13 at the connection terminal 12 while maintaining the connection between the external electrode 22 and the connection terminal 12 without disturbing the absorption.

  The widths of the electrode connection part 41, the external connection part 42, and the intermediate part 43 of the connection terminal 12 are the same width A1, respectively, in the length direction X of the ceramic capacitor element 11, and the end face 23a of the dielectric element body 21; This corresponds to the width W of the external electrode 22 provided in 23 b, but the present embodiment is not limited to this, and the connection terminal 12 and the ceramic capacitor are held while the connection terminal 12 holds the ceramic capacitor 10. As long as the effect of suppressing the propagation of the vibration generated in the dielectric element body 21 to the substrate 13 is obtained while maintaining the connection with the element 11, the electrode connection part 41, the external connection part 42, and the intermediate part Each width A1 with 43 may be different. If the connection terminal 12 holds the ceramic capacitor 10 and the vibration generated in the ceramic capacitor element 11 can be sufficiently suppressed from propagating to the substrate 13, the width A <b> 1 of the intermediate portion 41 is set to the external electrode 22. The width W may be wider or narrower.

  The thickness A2 of the connection terminal 12 is preferably 80 μm or more and 120 μm or less, and more preferably 90 μm or more and 110 μm or less. By setting the thickness A2 of the connection terminal 12 to 80 μm or more, the connection terminal 12 can maintain a sufficient strength to hold the ceramic capacitor 10. Further, by setting the thickness A2 of the connection terminal 12 to 120 μm or less, it is possible to sufficiently suppress the vibration generated in the ceramic capacitor element 11 from propagating to the substrate 13.

  As described above, according to the ceramic capacitor 10 according to the present embodiment, the connection terminal 12 is formed of a porous material, and the average porosity and the average pore diameter are within the above ranges. It is possible to efficiently suppress the vibration generated in step 1 from propagating to the substrate 13 and improve the effect of suppressing the vibration noise generated in the substrate 13.

  In addition, when a plurality of ceramic capacitors 10 are mounted on the substrate 13, vibrations transmitted to the substrate 13 are amplified when the plurality of ceramic capacitors 10 vibrate at the same period, so that vibration noise is generated from the substrate 13 due to resonance. However, according to the ceramic capacitor 10 according to the present embodiment, the vibration generated in the ceramic capacitor 10 by the connection terminal 12 can be prevented from propagating to the substrate 13, and thus the plurality of ceramic capacitors 10. Even if it is mounted on the substrate 13, it is possible to suppress an increase in the magnitude of vibration sound generated from the substrate 13 due to resonance of vibrations of the plurality of ceramic capacitors 10.

  As mentioned above, although this embodiment demonstrated the case where it applied to a multilayer ceramic capacitor as an example of a ceramic electronic component, the ceramic electronic component which concerns on this invention is not limited to the said embodiment. The ceramic electronic component according to the present invention can be applied to electronic components such as a piezoelectric vibrator, an inductor, a varistor, and a thermistor as long as the electronic component has a ceramic body.

  The contents of the invention according to the present embodiment will be described in detail below using examples and comparative examples, but the invention according to the present embodiment is not limited to the following examples.

<Examples 1-6, Comparative Examples 1-5>
[Production of ceramic capacitors]
In FIG. 1, the ceramic capacitor element has a length in the length direction X of 3.2 mm, a length in the width direction Y of 2.5 mm, and a length in the thickness direction Z of 2.5 mm. It is. The ceramic capacitor provided with the connection terminals used in Examples 1 to 6 and Comparative Examples 1 to 5 has a dielectric element body 21 in the longitudinal direction X of the ceramic capacitor element 11 like the ceramic capacitor 10 shown in FIG. A pair of porous connection terminals 12 are provided on both end faces 23 a and 23 b of the two so as to be connected to the external electrode 22. Table 1 shows the average porosity and average pore diameter of the connection terminals used in Examples 1 to 6 and Comparative Examples 1 to 5.

[Evaluation]
(Measurement of vibration sound volume (sound pressure))
When each ceramic capacitor was mounted on a substrate and an AC voltage was applied, the magnitude (sound pressure) of vibration sound generated from the substrate was measured. FIG. 6 is a diagram simply showing the configuration of the test apparatus used when measuring the sound pressure. As shown in FIG. 6, the test apparatus 50 includes an anechoic box 51, a sound collecting microphone (trade name: MI-1233, manufactured by Ono Sokki Co., Ltd.) 52, a power supply device 53, and an FFT analyzer (trade name: DS2100). , Manufactured by Ono Sokki Co., Ltd.). The ceramic capacitor 55 to be measured is installed in the anechoic box 51 in a state of being installed on the substrate 56. A substrate 56 provided with a ceramic capacitor 55 is provided with a pair of positive and negative electrodes at both ends thereof.

  The anechoic box 51 is formed in a box shape, and a sound absorbing material 57 is provided on the inner wall thereof. The sound-absorbing material 57 uses glass wool or the like, and the surface of the sound-absorbing material 57 is formed into a corrugated shape, thereby increasing the contact area of the sound wave and enhancing the sound-absorbing effect.

  The power supply device 53 is connected to a pair of positive and negative electrodes of the substrate 56 via a pair of wires 58, and the substrate 56 is suspended from the wires 58 and the ceramic capacitor 55 is placed in the anechoic box 51. It is arrange | positioned in the center part of the anechoic box 51 so as to oppose the bottom face. The power supply unit 53 applied an AC voltage of 3 Vp-p to the ceramic capacitor 55 with a frequency of 1 kHz to 10 kHz and a DC bias of 20 V.

  The sound collecting microphone 52 is provided on the bottom surface in the anechoic box 51 and is arranged so as to maintain a predetermined distance from the ceramic capacitor 55 installed in the central portion of the anechoic box 51. The FFT analyzer 54 analyzed the magnitude (sound pressure) of the vibration sound collected by the sound collection microphone 52.

  In the test apparatus 50, when the power supply device 53 applies a predetermined AC voltage toward the substrate 56, vibration is generated in the ceramic capacitor 55, vibration of the ceramic capacitor 55 is transmitted to the substrate 56, and vibration sound is generated from the substrate 56. To do. The vibration sound was collected using the sound collection microphone 52, and the collected vibration sound was analyzed by the FFT analyzer 54, whereby the magnitude (sound pressure) of the vibration sound generated from the substrate 56 was measured.

  Table 1 shows the measurement results of the sound pressure generated from the substrates on which the ceramic capacitors of Examples 1 to 5 and Comparative Example 1 are installed. In addition, as in the ceramic capacitor 10 shown in FIG. 1, a pair is provided so as to be connected to the external electrode 22 on both end surfaces 23 a and 23 b of the dielectric element body 21 in the longitudinal direction X of the ceramic capacitor element 11. In the ceramic capacitor provided with the connection terminals used in Examples 1 to 6 made of high quality metal, the sound pressure generated when the ceramic capacitor of Comparative Example 1 was used was used as a reference. If the sound pressure could be lower than the sound pressure of the vibration sound generated when the ceramic capacitor of Comparative Example 1 was used, it was judged that the effect of suppressing the sound pressure was good.

(Strength)
For the strength of the connection terminal, the height from the substrate to the ceramic capacitor element was measured after the ceramic capacitor element connected to the connection terminal was connected to the substrate. Thereafter, a load equal to or close to the compressive strength applied at the time of mounting was applied for a predetermined time from the upper side of the ceramic capacitor element, and the height from the substrate to the ceramic capacitor element was measured again. Table 1 shows the observation results of the strength of the connection terminals of each ceramic capacitor. Note that the strength of the connection terminal is sufficient if the fluctuation in height before and after applying compressive strength is within 5%, considering the actual mounting of the ceramic capacitor on the circuit board. (Circled in Table 1).

  As shown in Table 1, when a non-porous metal plate was used as a connection terminal as in Comparative Example 1, the sound pressure was higher than in Examples 1-6 and Comparative Examples 2-5, Since the non-porous metal plate is more likely to have solder rising than the porous metal plate, the length L of the above expression (1) of the substantial connection terminal is smaller than that of the porous metal plate. This is considered to be because a sufficient suppression effect is not obtained. Further, when a metal plate having an average porosity of about 25% is used as a connection terminal as in Comparative Example 2 as compared to a metal plate that is not porous as in Comparative Example 1, vibration noise is not sufficiently suppressed. It was confirmed that This is presumably because the vibration noise cannot be sufficiently absorbed by the metal plate. Further, even when a metal plate having an average porosity of about 50% was used as the connection terminal as in Comparative Example 4, if the average pore diameter was as small as about 0.1 μm, vibration noise was not sufficiently suppressed. confirmed. This is because when the average pore diameter of the connection terminal is as small as about 0.1 μm, the solder rises due to the capillary phenomenon, the length L of the above formula (1) of the connection terminal becomes short, and the spring of the connection terminal 12 This is probably because the constant increases. Further, when a metal plate having an average porosity of about 85% and an average pore diameter of about 10 μm is used as a connection terminal as in Comparative Example 3, the average porosity is too high, so that the connection terminal supports the ceramic capacitor element. It was confirmed that the required strength could not be maintained. In addition, even when the average porosity of the metal plate is about 50% as in Comparative Example 5, when the average pore diameter is about 40 μm, the pore diameter is too large, so that the connection terminal maintains the strength necessary to support the ceramic capacitor element. It was confirmed that it was not possible.

  On the other hand, in Examples 1-6, compared with the case where a metal plate which is not porous like Comparative Example 1 is used, vibration noise is suppressed, and the strength required for the connection terminal to support the ceramic capacitor element. It was confirmed that we were able to keep It is considered that the larger the average porosity and average pore diameter of the connection terminal, the smaller the Young's modulus E of the above formula (1), and the smaller the spring constant K of the connection terminal 12. Thereby, the effect which suppresses that the vibration which generate | occur | produced with the ceramic capacitor element propagates to a board | substrate is acquired. However, if the average porosity and average pore diameter of the connection terminals are too large, the connection terminals cannot maintain the strength necessary to support the ceramic capacitor element.

  Therefore, the ceramic capacitor is generated in the ceramic capacitor element 11 by using a porous metal plate having an average porosity of 30% to 80% and an average pore diameter of 1 μm to 30 μm as the connection terminal 12. It has been found that the strength required to support the ceramic capacitor element can be maintained while suppressing the transmitted vibration from propagating to the substrate 13.

  From the above, if the electronic component according to the present embodiment is mounted on a circuit board as a ceramic capacitor, the magnitude of vibration sound generated from the circuit board can be reduced. In addition, when the plurality of ceramic capacitors are mounted on the circuit board, the vibration noise generated from the circuit board can be reduced by the resonance of the vibrations of the plurality of ceramic capacitors. Therefore, the electronic component according to the present embodiment is useful when used as a multilayer ceramic capacitor mounted on a circuit board. In particular, the ceramic capacitor is used in various information processing apparatuses such as a notebook personal computer, a PDA, and a mobile phone. It can be suitably used as a ceramic capacitor mounted on a circuit board such as.

  As described above, the electronic component according to the present invention is useful when used as a multilayer ceramic capacitor mounted on a circuit board, and is used in circuits such as various information processing apparatuses such as notebook personal computers, PDAs, and mobile phones. Suitable for use on substrates.

10 Ceramic Capacitor 11 Ceramic Capacitor Element 12 Connection Terminal 13 Circuit Board (Board)
14A, 14B Substrate electrode 15A, 15B Wiring 16, 28 Solder 21 Dielectric element 22 External electrode (terminal electrode)
24, 25 Side surface 26 Dielectric layer 27 Internal electrode 41 Electrode connection portion 42 External connection portion 43 Intermediate portion 44 Pore

Claims (1)

A dielectric element having a plurality of dielectric layers and an internal electrode provided via the dielectric layer; and an element having an external electrode provided on an end surface of the dielectric element layer;
A pair of connection terminals,
The connection terminal is connected to the external electrode, is connected to the substrate, is connected to the substrate, is provided to face the dielectric element body, the lower surface of the dielectric element body, and the external connection Having an intermediate part for connecting the electrode connection part and the external connection part so as to have a gap between the part, and formed using a porous metal plate,
An electronic component having an average porosity of 30% to 80% and an average pore diameter of 1 μm to 30 μm.

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