JP2015204453A - Multilayer ceramic capacitor and mounting board thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer ceramic capacitor and a mounting board thereof.SOLUTION: A multilayer ceramic capacitor includes a ceramic body where a plurality of dielectric layers are laminated in the thickness direction, a plurality of first and second internal electrodes arranged to be exposed alternately from both end faces of the ceramic body via the dielectric layer, in the ceramic body, first and second external electrodes formed on both end faces of the ceramic body, and connected with the first and second internal electrodes, respectively, and first and second terminal electrodes including first and second bodies bonded to both end faces of the ceramic body, and connected with first and second external electrodes, respectively, and first and second leads elongating from the first and second bodies to project farther than the mounting surface of the ceramic body, and including first and second terminal electrodes including the first and second leads having ends formed of a curved surface.

Description

  The present invention relates to a multilayer ceramic capacitor and a mounting substrate thereof.

  Multi-Layered Ceramic Capacitors (MLCCs), one of the multilayer chip electronic components, can be used in various electronic devices due to their small size, high capacity, and easy mounting. it can.

  For example, the multilayer ceramic capacitor includes a video device such as a liquid crystal display (LCD) and a plasma display panel (PDP), a computer, a personal digital assistant (PDA), and a mobile phone. It can be used as a chip-type capacitor that is mounted on a substrate of various electronic products such as a telephone and serves to charge or discharge electricity.

  The multilayer ceramic capacitor may have a structure in which a plurality of dielectric layers and internal electrodes having different polarities are alternately stacked between the dielectric layers.

  At this time, since the dielectric layer has piezoelectricity, when a DC or AC voltage is applied to the multilayer ceramic capacitor, a piezoelectric phenomenon occurs between the internal electrodes to expand and contract the volume of the ceramic body according to the frequency. However, there is a possibility of generating periodic vibration.

  Such vibration is transmitted to the substrate via the external electrode of the multilayer ceramic capacitor and the solder connecting the external electrode and the substrate, and the entire substrate becomes an acoustic reflection surface, which can generate a vibration sound as noise. There is sex.

  The vibration sound corresponds to an audible frequency in the range of 20 to 20,000 Hz that gives an unpleasant feeling to a person. Such a vibration sound that gives an unpleasant feeling to a person is referred to as acoustic noise.

  The solder for connecting the external electrode and the substrate is formed to be inclined at a certain height along the surface of the external electrode from both side surfaces or both end surfaces of the ceramic body.

  At this time, as the volume and height of the solder are increased, the vibration of the multilayer ceramic capacitor is easily transmitted to the substrate, and the magnitude of acoustic noise generated is increased.

Korean Unexamined Patent Publication No. 2010-0087622

  Recently, acoustic noise generated in the multilayer ceramic capacitor may appear greatly in electronic devices due to low noise of components.

  Accordingly, an object of the present invention is to effectively reduce the acoustic noise of a multilayer ceramic capacitor.

  According to an embodiment of the present invention, a ceramic body in which a plurality of dielectric layers are stacked in a thickness direction and the ceramic body are alternately exposed from both end faces of the ceramic body through the dielectric layer. A plurality of first and second internal electrodes arranged in such a manner, and first and second external electrodes formed on both end faces of the ceramic body and connected to the first and second internal electrodes, respectively The first and second main body portions attached to both end surfaces of the ceramic main body and connected to the first and second external electrodes, respectively, and the mounting of the ceramic main body from the first and second main body portions There is provided a multilayer ceramic capacitor including first and second terminal electrodes including first and second lead portions extending so as to protrude from a surface and having end portions formed with curved surfaces.

  According to another embodiment of the present invention, there is provided a multilayer ceramic capacitor mounting substrate including a substrate having first and second electrode pads thereon and the multilayer ceramic capacitor disposed on the substrate. The

  In one embodiment of the present invention, the first and second lead portions of the first and second terminal electrodes may be formed in a cylindrical shape.

  In one embodiment of the present invention, the first and second lead portions of the first and second terminal electrodes may be formed in a semi-cylindrical shape convex toward the mounting surface.

  In one embodiment of the present invention, the first and second terminal electrodes have a plurality of unit lead portions formed by separating the first and second lead portions along the width direction of the ceramic body. Can consist of

  In one embodiment of the present invention, the first and second lead portions are formed on the first and second nickel (Ni) plating layers and the first and second nickel plating layers, respectively. 1 and a second tin (Sn) plating layer.

  In one embodiment of the present invention, the first and second conductive electrodes are provided between the first and second external electrodes and the first and second body portions of the first and second terminal electrodes. An adhesive layer or a high temperature soldering part can be formed respectively.

  In one embodiment of the present invention, the first and second external electrodes may be formed to extend from both end faces of the ceramic body to both side faces of the ceramic body and a part of both main faces.

  In one embodiment of the present invention, the first and second external electrodes are formed on the third and fourth nickel (Ni) plating layers and the third and fourth nickel plating layers, respectively. 3 and 4 tin (Sn) plating layers.

  According to one embodiment of the present invention, since the lead portion of the terminal electrode that contacts the substrate extends so as to protrude from the mounting surface of the ceramic body and the end portion is formed with a curved surface, the multilayer ceramic capacitor is formed on the substrate. There is an effect that acoustic noise can be reduced by reducing the contact area with the substrate when mounting and reducing the amount of vibration transmitted from the external electrode to the substrate.

1 is a perspective view schematically showing a multilayer ceramic capacitor according to an embodiment of the present invention. 1 is an exploded perspective view schematically showing a first and second terminal electrodes and a conductive adhesive layer separated from a multilayer ceramic capacitor according to an embodiment of the present invention. It is sectional drawing which follows the A-A 'line of FIG. It is a perspective view which shows the terminal electrode of the multilayer ceramic capacitor by other embodiment of this invention. FIG. 5 is an exploded perspective view schematically showing a first and second terminal electrodes and a conductive adhesive layer separated from a multilayer ceramic capacitor according to still another embodiment of the present invention. 1 is a side sectional view schematically showing a mounting board of a multilayer ceramic capacitor according to an embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for a clearer description.

  FIG. 1 is a perspective view schematically showing a multilayer ceramic capacitor according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating first and second terminal electrodes and a conductive adhesive layer from the multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 3 is a sectional view taken along line AA ′ of FIG. 1.

  1 to 3, the multilayer ceramic capacitor 100 according to the present embodiment includes a ceramic body 110, a plurality of first and second inner electrodes 121 and 122, first and second outer electrodes 131 and 132, and First and second terminal electrodes 141 and 142 are included.

  The ceramic body 110 is obtained by firing a plurality of dielectric layers 111 after laminating them in the thickness direction.

  At this time, the adjacent dielectric layers 111 in the ceramic body 110 can be integrated to such an extent that the boundary cannot be confirmed.

  The ceramic body 110 may be in a hexahedral shape, but the present invention is not limited to this.

  In the present embodiment, for convenience of explanation, the opposing surfaces in the thickness direction in which the dielectric layer 111 is laminated in the ceramic body 110 are upper and lower surfaces, the upper and lower surfaces are connected, and the first and second external electrodes are connected. The surfaces in the length direction on which 131 and 132 are formed are defined as both end surfaces, and the surfaces in the width direction that intersect perpendicularly and face both the end surfaces are defined as both side surfaces.

  The ceramic body 110 is not particularly limited in size, but may be configured to have a size of 2.0 mm (L) × 1.2 mm (W), for example, to implement the high-capacity multilayer ceramic capacitor 100. it can.

  In addition, cover layers 112 and 113 having a predetermined thickness can be formed on the upper and lower surfaces, which are the outermost surfaces of the ceramic body 110, as necessary.

  The thickness of the dielectric layer 111 may be arbitrarily changed according to the capacity design of the multilayer ceramic capacitor 100.

The dielectric layer 111 may include a ceramic material having a high dielectric constant, such as a BaTiO ₃ ceramic powder, but the present invention is not limited thereto.

Examples of the BaTiO ₃ ceramic powder include (Ba _1-x Ca _x ) TiO ₃ , Ba (Ti _1-y Ca _y ) O ₃ , (Ba) in which Ca, Zr and the like are partly dissolved in BaTiO _{3. 1-x} Ca _x ) (Ti _1-y Zr _y ) O _3, Ba (Ti _1-y Zr _y ) O _{3, and the} like, but the present invention is not limited to this.

  Meanwhile, a ceramic additive, an organic solvent, a plasticizer, a binder, a dispersant, and the like can be further added to the dielectric layer 111 together with the ceramic powder.

  As said ceramic additive, a transition metal oxide or carbide, rare earth elements, magnesium (Mg), aluminum (Al), etc. can be used, for example.

  The first and second internal electrodes 121 and 122 are formed on the ceramic sheet forming the dielectric layer 111 and stacked, and then fired alternately inside the ceramic body 110 via the single dielectric layer 111. Placed in.

  The first and second internal electrodes 121 and 122 are a pair of electrodes having different polarities, and are disposed to face each other in the stacking direction of the dielectric layer 111 and are disposed in the middle. The layers 111 can be electrically isolated from each other.

  One end of each of the first and second internal electrodes 121 and 122 is exposed from both end surfaces of the ceramic body 110.

  As described above, the ends of the first and second internal electrodes 121 and 122 that are alternately exposed from both end surfaces of the ceramic body 110 are respectively connected to the first and second external electrodes 131 and 132 at both ends of the ceramic body 110. They can be connected and electrically coupled.

  At this time, the first and second internal electrodes 121 and 122 are formed of a conductive metal, and for example, nickel (Ni) or a nickel (Ni) alloy can be used as the material thereof. It is not limited to.

  With the above configuration, when a predetermined voltage is applied to the first and second external electrodes 131 and 132, electric charges are accumulated between the first and second internal electrodes 121 and 122 facing each other.

  At this time, the capacitance of the multilayer ceramic capacitor 100 is proportional to the overlapping area of the first and second internal electrodes 121 and 122 that overlap in the stacking direction of the dielectric layer 111.

  The first and second external electrodes 131 and 132 are for external electrodes containing copper (Cu) in order to have good electrical characteristics and provide high reliability such as excellent heat cycle resistance and moisture resistance. Although the conductive paste can be formed by firing, the present invention is not limited to this.

  The first and second external electrodes 131 and 132 are formed on both end surfaces of the ceramic body 110, respectively, and are connected to and electrically connected to the exposed ends of the first and second internal electrodes 121 and 122, respectively. Can.

  In addition, the first and second external electrodes 131 and 132 may be formed to extend from both end surfaces of the ceramic body 110 to both side surfaces of the ceramic body 110 and a part of both main surfaces as necessary.

  Further, the surfaces of the first and second external electrodes 131 and 132 can be plated as necessary to form a plating layer.

  At this time, the plating layer is formed by plating nickel (Ni) on the first and second external electrodes 131 and 132, and tin (Sn) on the nickel plating layer. And a tin plating layer formed in the same manner.

  The first and second terminal electrodes 141 and 142 may include first and second body portions 141a and 142a and first and second lead portions 141b and 142b.

  The first and second main body portions 141a and 142a are attached to the first and second external electrodes 131 and 132 on both end faces of the ceramic main body 110, and are respectively connected to the first and second external electrodes 131 and 132. It is a part that is connected and electrically connected.

  The first and second lead portions 141b and 142b are portions extending from the lower ends of the first and second main body portions 141a and 142a so as to protrude downward from the mounting surface of the ceramic main body 110, respectively. This is a portion that is electrically connected in contact with an electrode pad or a circuit pattern during mounting.

  At this time, the first and second lead parts 141b and 142b may have a curved lower end part in contact with the substrate.

  In addition, the first and second lead portions 141b and 142b may be formed to have a circular cross section so as to minimize the contact area with the substrate, but the present invention is not limited thereto. Absent.

  For example, as shown in FIG. 4, the terminal electrode 141 ′ of the present invention protrudes downward in a semicircular shape from the lower end of the main body 141 a ′ and the main body 141 a ′ attached on the external electrode. In this case, the lead portion 141c ′ may be formed in a semi-cylindrical shape having a flat surface 141b ′ at the upper end and projecting downward.

  That is, the lead portion of the terminal electrode according to the present invention may be changed into various shapes within a range where the portion in contact with the substrate has a curved surface.

  According to the present embodiment, since the first and second lead portions 141b and 142b of the first and second terminal electrodes 141 and 142 are formed with curved surfaces, the first and second lead portions 141b and 142b and The area where the first and second electrode pads 221 and 222 are in contact with each other is reduced.

  Accordingly, acoustic noise can be reduced by reducing the amount of vibration generated by the piezoelectricity of the multilayer ceramic capacitor 100 and transmitted to the substrate via the first and second external electrodes 131 and 132.

  Further, the surface of the first and second lead portions 141b and 142b can be plated as necessary to form a plating layer.

  By the plating layer, soldering can be performed more efficiently when the first and second lead portions 141b and 142b are mounted on the substrate.

  At this time, the plating layer includes a nickel plating layer formed by plating nickel (Ni) on the first and second lead portions 141b and 142b, and tin (Sn) plating on the nickel plating layer. And a tin plating layer formed in the same manner.

  On the other hand, a conductive adhesive layer made of a conductive paste containing a conductive resin is provided between the main body portions 141a, 142a of the first and second terminal electrodes 141, 142 and the first and second external electrodes 131, 132. 151, 152 or a high temperature solder can be formed.

  FIG. 5 is an exploded perspective view schematically showing the first and second terminal electrodes and the conductive adhesive layer separated from a multilayer ceramic capacitor according to still another embodiment of the present invention.

  Hereinafter, in order to avoid duplication about the part similar to multilayer ceramic capacitor 100 'by one Embodiment of this invention mentioned above, the specific description is abbreviate | omitted and the 1st and 2nd terminal electrode 161 which has a different structure , 162 will be specifically described.

  Referring to FIG. 5, the first and second terminal electrodes 161 and 162 of the present embodiment include first and second body portions 161a and 162a and a plurality of unit lead portions 161b, 161c, 162b, and 162c. Can do.

  The first and second main body portions 161a and 162a are attached to the first and second external electrodes 131 and 132 on both end faces of the ceramic main body 110 and connected to the first and second external electrodes 131 and 132, respectively. It is a part electrically connected.

  The unit lead portions 161b, 161c, 162b, 162c are portions formed so as to protrude downward from the mounting surface of the ceramic body 110 from the lower ends of the first and second body portions 161a, 162a, respectively. This is a portion that is electrically connected to an electrode pad or a circuit pattern when mounted on a substrate.

  At this time, the unit lead parts 161 b, 161 c, 162 b, 162 c can be formed at predetermined intervals 163, 164 along the width direction of the ceramic body 110.

  In the first and second terminal electrodes 161 and 162 of the present invention, the number of unit lead portions 161b, 161c, 162b, and 162c is not limited to that illustrated. If necessary, three or more unit lead parts may be formed on the first and second body parts 161a and 162a of the first and second terminal electrodes 161 and 162, respectively.

  According to the present embodiment, since the lead portions of the first and second terminal electrodes 161 and 162 are configured to be separated into a plurality of unit lead portions, the lead portion and the first and first terminal portions are compared with the above-described embodiment. The area where the two electrode pads 221 and 222 come into contact with each other becomes smaller.

  Accordingly, the acoustic noise can be further reduced by further reducing the amount of vibration generated by the piezoelectricity of the multilayer ceramic capacitor 100 ′ and transmitted to the substrate via the first and second external electrodes 131 and 132. .

  FIG. 6 is a side cross-sectional view schematically showing a multilayer ceramic capacitor mounting board according to an embodiment of the present invention.

  Referring to FIG. 6, the mounting substrate 200 of the multilayer ceramic capacitor 100 according to the present embodiment includes a substrate 210 on which the multilayer ceramic capacitor 100 is mounted, and first and second substrates formed on the top surface of the substrate 210. Electrode pads 221, 222.

  In the multilayer ceramic capacitor 100, the first and second lead portions 141b and 142b of the first and second terminal electrodes 141 and 142 formed so as to protrude from the lower surface, which is the mounting surface of the ceramic body 110, are provided on the substrate 210. The first and second electrode pads 221 and 222 can be electrically connected to the substrate 210 using the solder 231 and 232 in a state of being in contact with the first and second electrode pads 221 and 222.

  On the other hand, voltages having different polarities are applied to the first and second external electrodes 131 and 132 formed at both ends of the multilayer ceramic capacitor 100 with the multilayer ceramic capacitor 100 mounted on the substrate 210 as described above. The ceramic body 110 expands and contracts in the thickness direction due to the inverse piezoelectric effect of the dielectric layer 111, and both end portions of the first and second external electrodes 131 and 132 are Poisson effects. As a result, the ceramic body 110 contracts and expands contrary to the expansion and contraction in the thickness direction.

  Such contraction and expansion generates vibration. In addition, the vibration is transmitted from the first and second external electrodes 131 and 132 to the substrate 210, whereby sound is radiated from the substrate 210 and becomes acoustic noise.

  However, according to the present embodiment, since the end portions of the lead portions 141b and 142b of the first and second terminal electrodes 141 and 142 are formed with curved surfaces, the first and second lead portions 141b and 142b and the first lead electrodes 141b and 142b The contact area between the first and second electrode pads 221 and 222 is reduced. As a result, the first and second electrode pads 221 and 222 are generated by the piezoelectricity of the multilayer ceramic capacitor 100 and transmitted to the substrate through the first and second external electrodes 131 and 132. The acoustic noise can be reduced by reducing the amount of vibration.

  Further, according to the present embodiment, the solder 231 and 232 are fixed to the surface of the cylindrical portion of the first and second lead portions 141b and 142b, so that a sufficient surface area is secured to which the solder 231 and 232 are fixed. Therefore, even if the amount of the solder 231 and 232 is reduced, the fixing strength of the first and second external electrodes 131 and 132 is not reduced.

  In the mounting substrate 200 of the multilayer ceramic capacitor 100 according to the present embodiment, the solders 231 and 232 are connected to the first and second lead portions 141b and 142b of the first and second terminal electrodes 141 and 142, respectively. 2 enters the groove provided between the two electrode pads 221 and 222.

  Therefore, the solder 231 and 232 do not contact the ceramic main body 110 and the first and second external electrodes 131 and 132 of the multilayer ceramic capacitor 100, but only the lower edge surfaces of the first and second lead portions 141b and 142b. Can be formed to a minimum height.

  Therefore, in the multilayer ceramic capacitor 100 according to the present embodiment, the heights of the solders 231 and 232 are minimized, and the elastic force of the first and second terminal electrodes 141 and 142 acts efficiently. Acoustic noise can be reduced by reducing the transmission of vibrations generated from the substrate to the substrate 210.

  Recently, as electronic products have become smaller and thinner, substrates have been reduced, and high-density mounting of electronic components has been demanded.

  In particular, in the case of general-purpose passive components, the mounting area increases as the mounting quantity increases. Therefore, the correspondence to high-density mounting is increasing.

  According to the present embodiment, the volumes of the solders 231 and 232 are reduced to the minimum by the first and second lead portions 141b and 142b of the first and second terminal electrodes 141 and 142 whose lower end portions are curved. By reducing the areas of the first and second electrode pads 221 and 222 formed on the substrate 210, high-density mounting is possible without damaging the mechanical strength such as the fixing strength of the external electrodes.

  In addition, even if a plurality of multilayer ceramic capacitors are mounted on a substrate at a narrow pitch, a solder bridge that connects the multilayer ceramic capacitors does not occur, so that the reliability of the components can be improved. There is an effect that can be done.

  The embodiment of the present invention has been described in detail above, but the scope of the present invention is not limited to this, and various modifications and variations can be made without departing from the technical idea of the present invention described in the claims. It will be apparent to those having ordinary knowledge in the art.

100 multilayer ceramic capacitor 110 ceramic body 111 dielectric layer 112, 113 cover layer 121, 122 first and second internal electrodes 131, 132 first and second external electrodes 141, 142, 161, 162 first and second Terminal electrodes 141a, 142a, 161a, 162a first and second body parts 141b, 142b, 161b, 162b first and second lead parts 151, 152 first and second conductive adhesive layers 200 mounting substrate 210 Substrate 221, 222 First and second electrode pads 231, 232 Solder

Claims (16)

A ceramic body in which a plurality of dielectric layers are laminated in the thickness direction;
A plurality of first and second internal electrodes arranged to be alternately exposed from both end faces of the ceramic body through the dielectric layer in the ceramic body;
First and second external electrodes formed on both end faces of the ceramic body and connected to the first and second internal electrodes, respectively;
First and second main body portions attached to both end surfaces of the ceramic main body and connected to the first and second external electrodes, respectively, and mounting surfaces of the ceramic main body from the first and second main body portions First and second terminal electrodes including first and second lead portions that extend so as to protrude further and have end portions formed of curved surfaces;
Multilayer ceramic capacitor.   The multilayer ceramic capacitor according to claim 1, wherein the first and second terminal electrodes have the first and second lead portions formed in a columnar shape.   2. The multilayer ceramic capacitor according to claim 1, wherein the first and second terminal electrodes are formed in a semi-cylindrical shape in which the first and second lead portions are convex toward the mounting surface.   The said 1st and 2nd terminal electrode consists of a several unit lead part in which the said 1st and 2nd lead part was formed separately along the width direction of the said ceramic main body, respectively. Multilayer ceramic capacitor.   The first and second lead portions include first and second nickel (Ni) plating layers, and first and second tin (Sn) formed on the first and second nickel plating layers, respectively. The multilayer ceramic capacitor according to claim 1, comprising: a plating layer.   First and second conductive adhesive layers or high temperature soldering formed between the first and second external electrodes and the first and second body portions of the first and second terminal electrodes, respectively. The multilayer ceramic capacitor according to claim 1, further comprising a portion.   2. The multilayer ceramic capacitor according to claim 1, wherein the first and second external electrodes are formed to extend from both end faces of the ceramic body to both side faces of the ceramic body and a part of both main faces.   The first and second external electrodes include third and fourth nickel (Ni) plating layers, and third and fourth tin (Sn) formed on the third and fourth nickel plating layers, respectively. The multilayer ceramic capacitor according to claim 1, comprising: a plating layer. A substrate having first and second electrode pads thereon;
A multilayer ceramic capacitor installed on the substrate;
Including
The multilayer ceramic capacitor is arranged such that a plurality of dielectric layers are laminated in the thickness direction, and are alternately exposed from both end faces of the ceramic body through the dielectric layer in the ceramic body. A plurality of first and second internal electrodes, first and second external electrodes formed on both end faces of the ceramic body and connected to the first and second internal electrodes, respectively, and both ends of the ceramic body The first and second main body portions attached to the surface and connected to the first and second external electrodes, respectively, and the first and second main body portions so as to protrude from the mounting surface of the ceramic main body. A multilayer ceramic capacitor mounting substrate including first and second terminal electrodes including first and second lead portions extending and having curved end portions.   The multilayer ceramic capacitor mounting substrate according to claim 9, wherein the first and second terminal electrodes have the first and second lead portions formed in a columnar shape.   The multilayer ceramic capacitor mounting substrate according to claim 9, wherein the first and second terminal electrodes are formed in a semi-cylindrical shape in which the first and second lead portions are convex toward the mounting surface.   The said 1st and 2nd terminal electrode consists of a several unit lead part in which the said 1st and 2nd lead part was formed separately along the width direction of the said ceramic main body, respectively. Multilayer ceramic capacitor mounting board.   The first and second lead portions include first and second nickel (Ni) plating layers, and first and second tin (Sn) formed on the first and second nickel plating layers, respectively. The multilayer ceramic capacitor mounting substrate according to claim 9, further comprising: a plating layer.   First and second conductive adhesive layers or high temperature soldering formed between the first and second external electrodes and the first and second body portions of the first and second terminal electrodes, respectively. The multilayer ceramic capacitor mounting board according to claim 9, further comprising a portion.   The multilayer ceramic capacitor mounting board according to claim 9, wherein the first and second external electrodes are formed to extend from both end faces of the ceramic body to both side faces of the ceramic body and a part of both main faces. .   The first and second external electrodes include third and fourth nickel (Ni) plating layers, and third and fourth tin (Sn) formed on the third and fourth nickel plating layers, respectively. The multilayer ceramic capacitor mounting substrate according to claim 9, further comprising: a plating layer.

Images