LAMINATED ELECTRONIC COMPONENT AND MOUNTING STRUCTURE THEREOF
20190206628 ยท 2019-07-04
Assignee
Inventors
Cpc classification
H05K3/3442
ELECTRICITY
Y02P70/50
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H01G4/232
ELECTRICITY
International classification
H05K1/18
ELECTRICITY
H01G4/232
ELECTRICITY
Abstract
A laminated electronic component includes a rectangular parallelepiped shaped stacked body including dielectric layers and internal electrode layers which are alternately laminated and a pair of first conductors and a pair of second conductors which are disposed on an outer surface of the stacked body. The first conductors are disposed in portions which include centers of long sides of a first principal surface which is positioned in a direction of lamination of the dielectric layers and the internal electrode layers of the stacked body, and do not include a vertex of the stacked body so as to extend from first side surfaces to the first principal surface. The second conductors are disposed on second side surfaces, and the first conductors and the second conductors are spaced apart from each other on an outer surface and electrically connected to each other via the internal electrode layers.
Claims
1. A laminated electronic component comprising: a stacked body having a rectangular parallelepiped shape, the stacked body comprising dielectric layers and internal electrode layers which are alternately laminated; and a pair of first conductors and a pair of second conductors disposed on an outer surface of the stacked body, the stacked body comprising a pair of first and second principal surfaces which has a rectangular shape and is positioned in a direction of lamination of the dielectric layers and the internal electrode layers, a pair of first side surfaces adjacent to long sides of the pair of first and second principal surfaces, and a pair of second side surfaces adjacent to short sides of the pair of first and second principal surfaces, the pair of first conductors being disposed in portions which include centers of the long sides of the first principal surface or the second principal surface, and do not include a vertex of the stacked body, and the pair of first conductors comprising side surface sections which extend from the long sides on the pair of first side surfaces, and projection sections which extend from the long sides or the short sides on the first principal surface, the pair of second conductors being disposed on the pair of first side surfaces or the pair of second side surfaces, and the pair of first conductors and the pair of second conductors being spaced apart from each other on the outer surface and electrically connected to each other via the internal electrode layers.
2. The laminated electronic component according to claim 1, wherein a length in the direction of lamination of each of the side surface sections of the pair of first conductors is equal to or less than 0.4 time a length in the direction of lamination of the stacked body.
3. The laminated electronic component according to claim 1, wherein the side surface sections of the pair of first conductors, and the pair of second conductors are respectively disposed on different side surfaces among the pair of first side surfaces and the pair of second side surfaces.
4. The laminated electronic component according to claim 3, wherein the side surface sections of the pair of first conductors are disposed on the pair of first side surfaces, and the pair of second conductors is disposed on the pair of second side surfaces.
5. The laminated electronic component according to claim 1, wherein the side surface sections of the pair of first conductors and the pair of second conductors are disposed on one of the pair of first side surfaces.
6. The laminated electronic component according to claim 1, wherein the pair of second conductors is disposed over an entirety in the direction of lamination of the pair of first side surfaces or the pair of second side surfaces.
7. A mounting structure, comprising: the laminated electronic component according to claim 1; and a substrate which is joined with the projection sections of the pair of first conductors of the laminated electronic component.
8. The laminated electronic component according to claim 1, wherein when a length of the long sides is denoted by L and a length of the pair of first conductors along the long sides is denoted by W, a ratio of W to L is equal to or less than 0.35.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DESCRIPTION OF EMBODIMENTS
[0025] A laminated electronic component and a mounting structure will be described with reference to the drawings. Moreover, in each drawing, the same reference numerals are given to the same members and portions and duplicate description will be omitted. Some of the reference numerals are omitted in some drawings. In addition, for ease of description, xyz coordinate axes are attached to each drawing.
First Embodiment
[0026] As illustrated in
[0027] A first principal surface 7A and a second principal surface 7B which are a pair of opposed rectangular principal surfaces are positioned in the direction of lamination of the stacked body 2 in the laminated electronic component 1 of the embodiment. Both of the first principal surface 7A and the second principal surface 7B are configured of a pair of long sides 8 and a pair of short sides 9. The stacked body 2 has a pair of opposed first side surfaces 10 adjacent to the long sides 8 and a pair of opposed second side surfaces 11 adjacent to the short sides 9 of the first and second principal surfaces 7A and 7B
[0028] The first conductor 3 has a side surface section 3a disposed on the first side surface 10 and a projection section 3b extending from the side surface section 3a on the first principal surface 7A. The side surface section 3a is disposed closer to the first principal surface 7A than a center portion of the first side surface 10 in the direction of lamination. The second conductor 4 is disposed on the second side surface 11 and is spaced apart from the first conductor 3. That is, the first conductor 3 and the second conductor 4 are spaced apart from each other and are not connected to each other on the outer surface of the stacked body 2.
[0029] In the embodiment, as illustrated in
[0030] As illustrated in
[0031] As illustrated in
[0032] In
[0033] As described above, the lead-out sections 6a are disposed so as to be alternately exposed to any one of the pair of first side surfaces 10 and are electrically connected to the side surface sections 3a of the first conductors 3. The lead-out sections 6b are disposed so as to be alternately exposed to any one of the pair of second side surfaces 11 and are electrically connected to the second conductors 4. The internal electrode layers 6 including the lead-out sections 6a and 6b are disposed such that conduction is not disposed between the first conductors 3 and between the second conductors 4. Moreover, in
[0034] The internal electrode layer 6 (
[0035]
[0036] Since an exposed section of the lead-out section 6a in the first side surface 10 is directivity connected to the first conductor 3, from the viewpoint that symmetry of vibration is maintained and factors causing vibration of the substrate can be reduced when being mounted, it is preferable that the center portions 8c of the long sides 8 are included.
[0037] Moreover, structures of the dielectric layers 5 and the internal electrode layers 6 illustrated in
[0038] The dimensions of each portion will be described with reference to
[0039] The mounting structure of the laminated electronic component of the embodiment will be described.
[0040] In
[0041] On the other hand, as illustrated in
[0042] As illustrated in
[0043] For example, in a laminated ceramic capacitor which is one of the laminated electronic components, as the dielectric layer 105, a ferroelectric material such as barium titanate is used, and as the internal electrode layer 106, a metal material such as Ni is used. In addition, usually, the external electrode 103 is formed by baking Cu paste as a base electrode and applying Ni and Sn plating on a surface thereof.
[0044] In the laminated electronic component of the related art, as illustrated in
[0045] When an AC voltage together with a DC voltage (DC bias) is applied to the laminated ceramic capacitor which is mounted in such a state, a piezoelectric property occurs in the dielectric layers 105 due to the electrostriction effect by the DC voltage and piezoelectric vibration occurs due to the AC voltage. Furthermore, the piezoelectric vibration of the laminated ceramic capacitor is transmitted to the substrate 12 via the solders 114, and the substrate 12 vibrates. When the substrate 12 resonates at a resonance frequency in an audible range, a vibration sound called acoustic noise occurs.
[0046] As an example, in a case of a mounting structure of the related art in which the laminated ceramic capacitor which is the laminated electronic component of the related art is mounted on the substrate 12, acoustic noise was measured. For the measurement, as the laminated ceramic capacitor, Type 1005 laminated ceramic capacitor (capacity 10 F, rated voltage 4V, hereinafter, referred to as an evaluation component) and as the substrate 12, a substrate formed of a FR material of 10040 mm and thickness of 0.8 mm were used. The laminated ceramic capacitor was mounted on a center of the substrate 12 using solder of SnAgCu (SAC) type. After mounting the evaluation component on the substrate 12, a mounting state was observed with a microscope, and it was confirmed that a fillet height of the solder 114 was 460 m and a gap C between the substrate 12 and the evaluation component was 45 m.
[0047] As illustrated in
[0048] Moreover, in
[0049] Next, simulation of the piezoelectric vibration of the laminated ceramic capacitor was performed. First, in a state where the DC voltage (DC bias) of 4V is applied to the evaluation component, impedance is measured. A measurement result is illustrated in
[0050] Simulation of the impedance was performed by using a model (dielectric material: barium titanate based material, internal electrode: Ni, external electrode: Cu, stacked body dimensions: 1100620620 m, and external electrode thickness 20 m) based on the evaluation component. For piezoelectric resistance peaks existing in a frequency region of 2 GHz or more, fitting of material parameters of the evaluation component was performed so as to match an actually measured value.
[0051] The parameters (elastic stiffness c.sub.ij and piezoelectric constant e.sub.ij) of the dielectric layer 105 obtained by fitting are indicated in Table 1. From Table 1, it can be seen that there is anisotropy (c.sub.11>c.sub.33 and c.sub.22>c.sub.33) in the material characteristic of the dielectric layer 105 of the evaluation component. This may be caused by a compression stress by the internal electrode layers 106.
TABLE-US-00001 TABLE 1 Elastic Stiffness and Piezoelectric Constant of Dielectric Layer c.sub.11.sup.E 281.5 10.sup.9 N/m.sup.2 c.sub.12.sup.E 117.2 10.sup.9 N/m.sup.2 c.sub.13.sup.E 57.2 10.sup.9 N/m.sup.2 c.sub.22.sup.E 230.8 10.sup.9 N/m.sup.2 c.sub.23.sup.E 57.2 10.sup.9 N/m.sup.2 c.sub.33.sup.E 104.3 10.sup.9 N/m.sup.2 c.sub.44.sup.E 30.9 10.sup.9 N/m.sup.2 c.sub.55.sup.E 30.9 10.sup.9 N/m.sup.2 c.sub.66.sup.E 68.9 10.sup.9 N/m.sup.2 e.sub.31 22.2 C/m.sup.2 e.sub.32 27.8 C/m.sup.2 e.sub.33 4.75 C/m.sup.2 e.sub.15 2.94 C/m.sup.2 e.sub.24 2.94 C/m.sup.2
[0052] A model of the mounting structure was created and simulation was performed based on the parameters of the obtained dielectric layer 105 and the mounting substrate 21 (fillet height 460 m and a gap between the substrate and the evaluation component 45 m) which is used in the measurement.
[0053] In addition, a vibration mode was calculated in the audible frequency region (20 Hz to 20 kHz) of the evaluation component using the obtained parameters. The model was used in the calculation. A calculation result in 10 kHz is illustrated in
[0054] In the embodiment, it is possible to fix the node-shaped sections 15 of the stacked body to the substrate 12 via the first conductors 3 by providing the first conductors 3 on the node-shaped sections 15 existing in the laminated electronic component 1.
[0055] Even if the lead-out sections 6a exist only in a part of the direction of lamination, that is, in the vicinity of the first principal surface 7A, simulation of acoustic noise was performed using the following model of the embodiment to confirm that the node-shaped sections 15 of the vibration exist and an effect is achieved on reduction of acoustic noise by the embodiment. External dimensions of the stacked body 2 are the same as those of the evaluation component and the internal electrode layers 6 having the lead-out sections 6a are disposed in a range of 90 m the first principal surface 7A in the direction of lamination. As illustrated in
[0056]
[0057] If results obtained by the simulation of the sound pressure in the embodiment are averaged over a frequency region of 5 Hz to 20 kHz, an average value of the sound pressure level was reduced by 19 dBa with respect to the mounting structure of the related art.
[0058] Moreover, in the embodiment, in the simulation described above, a ratio (W1/L1) of W1 (280 m) to L1 (1100 m) was set to 0.25, but even if the ratio is set to 0.35, the sound pressure level can be reduced by approximately 10 dBA with respect to that of the related art. In addition, it is preferable that W1/L1 is equal to or greater than 0.2 from the viewpoint of mountability.
[0059] Moreover, in the mounting structure of the embodiment, the laminated electronic component 1 does not directivity come into contact with the mounting surface of the substrate 12. Particularly, a ratio (C/H0) of C that is the gap between the laminated electronic component 1 and the mounting surface of the substrate 12 to H0 is equal to or greater than 0.05, particularly, is equal to or greater than 0.1.
[0060] Furthermore, according to the results of the vibration mode analysis of the evaluation component described above and the embodiment, since the vibration amplitude is large in the vicinity of the center of each surface constituting the stacked body 2, it is preferable that a ratio (H1/H0) of H1 to H0 is equal to or less than 0.4. In addition, since the vibration amplitude is large in the vicinity of the center even in the principal surface 7, a length P1 of the first conductor 3 in a direction perpendicular to the long side 8 is equal to or less than 0.25 as a ratio (P1/L2) to L2.
[0061] As described above, in the embodiment, the laminated electronic component 1 is fixed to the substrate 12 by the first conductors 3. Therefore, the first conductors 3 are disposed in the node-shaped sections 15 of the laminated electronic component 1, that is, in portions which include the center portions 8c of the long sides 8 of the first principal surface 7A and do not include the vertexes V of the stacked body 2, and thereby acoustic noise can be suppressed. On the other hand, the second conductors 4 are responsible for electrical connection between the internal electrode layers 6 and do not contribute to fixation with the substrate 12. Therefore, the second conductors 4 do not come into contact with the substrate 12, may be disposed in positions spaced apart from the first conductors 3 on the outer surface of the stacked body 2, and may be disposed so as to include the centers of the first and second side surfaces 10 and 11 and the vertexes V of the stacked body 2.
[0062] As illustrated in
[0063] Moreover, in the embodiment, the first conductors 3 may be disposed not only on portions of the first principal surface 7A side but also on the same portions of the second principal surface 7B side as illustrated in
Second Embodiment
[0064] In a second embodiment, as illustrated in
Third Embodiment
[0065] In a third embodiment, as illustrated in
[0066] As described above, the second conductors 4 is only required to be spaced apart from the first conductors 3 in the first side surfaces 10, may be disposed on the same side surfaces as the side surface sections 3a of the first conductors 3, or may be disposed on a boundary between the first side surface 10 and the second side surface 11. In addition, the second conductors 4 may be not only one pair but also two or more pairs.
[0067] In addition, the internal electrode layer 6 including only the lead-out section 6a may be provided. That is, the internal electrode layer 6 including only the lead-out section 6a may be disposed closest to the first principal surface 7A of the stacked body 2, the internal electrode layers 6 including the lead-out section 6a and the lead-out section 6b, and the internal electrode layers 6 including only the lead-out sections 6b may be sequentially disposed and thereby the second conductors 4 may be disposed spaced apart from the long side 8 or the short side 9.
[0068] In each embodiment described above, the shape and the disposition of the internal electrode layers 6 may be appropriately changed according to the disposition of the first conductors 3 and the second conductors 4.
[0069] Moreover, in each embodiment described above, for the first conductors 3 and the second conductors 4, the shapes thereof are mainly formed in rectangular shapes and preferable ranges of the dimensions and ratios are described, but the shapes of the first conductor 3 and the second conductor 4 are not limited to the rectangular shape, and other various shapes and irregular shapes are acceptable. In addition, various changes and modifications can be made without departing from the scope of the invention based on the description regarding the vibration modes and the node-shaped sections 15 of the laminated electronic component 1 confirmed by the simulation described above.
[0070] The invention is particularly suitably used in a case where, for example, a laminated ceramic capacitor, which uses a ferroelectric material such as barium titanate based material for the dielectric layer 5 and uses a metal material such as Ni, Cu, Ag, and AgPd for the internal electrode layer 6, is the laminated electronic component 1. Also in other laminated electronic components 1, it is applicable to a case where it is necessary to suppress excitation of the substrate 12 on which the laminated electronic component 1 is mounted and the like due to the piezoelectric vibration of the laminated electronic component 1 itself. The invention can exert a remarkable effect particularly in the laminated electronic component 1 of a model of Type 1005 or larger (external dimensions of Type 1005 or larger).
[0071] The invention is applicable to various existing laminated electronic components 1. In addition, there is also an advantage that a special jig is not required for mounting on the substrate 12.
[0072] Moreover, in the embodiment, although the laminated ceramic capacitor having a general shape is described as an example of the laminated electronic component 1, in addition, it is applicable to a laminated electronic component 1 of a thin type or having various structures.
[0073] Furthermore, as the first conductor 3 and the second conductor 4, for example, a material which is obtained by plating Ni and Sn on a base electrode made of Cu which is often used as the external electrode of the laminated ceramic capacitor, may be employed, but the first conductor 3 and the second conductor 4 which are composed only of a plating electrode without using the base electrode, can be suitably used. Since the base electrode composed of Cu is relatively soft, the piezoelectric vibration of the stacked body 2 is absorbed and attenuated to some extent, but in a case of only the plating electrode, the piezoelectric vibration of the stacked body 2 is not attenuated by the first conductor 3 and acoustic noise is remarkable. Therefore, it is possible to obtain a larger acoustic noise suppression effect by applying the invention.
REFERENCE SIGNS LIST
[0074] 1: Laminated electronic component
[0075] 2, 102: Stacked body
[0076] 3: First conductor
[0077] 103: External electrode
[0078] 4: Second conductor
[0079] 5, 105: Dielectric layer
[0080] 6, 106: Internal electrode layer
[0081] 7A: First principal surface
[0082] 7B: Second principal surface
[0083] 8: Long side
[0084] 8c: Center of long side
[0085] 9: Short side
[0086] 9c: Center of short side
[0087] 10: First side surface
[0088] 11: Second side surface
[0089] 12: Substrate
[0090] 13: Land pattern
[0091] 14, 114: Solder
[0092] 15: Node-shaped section
[0093] 21: Mounting substrate
[0094] 22: Anechoic box
[0095] 23: Sound collecting microphone
[0096] 24: Amplifier
[0097] 25: FET analyzer