JP4670321B2 - Multilayer ceramic electronic components - Google Patents

Description

  The present invention relates to a multilayer ceramic electronic component, and more particularly to a multilayer ceramic electronic component mounted on a printed wiring board.

  As a multilayer ceramic electronic component mounted on a printed wiring board, which is of interest to the present invention, there is one that constitutes a multilayer ceramic substrate as described in, for example, Japanese Patent Application Laid-Open No. 2003-342063 (Patent Document 1).

  Since the multilayer ceramic substrate is used in a state where it is mounted on the printed wiring board, it is provided with at least two mounting electrodes connected to the printed wiring substrate on one main surface of the component main body. Each of these mounting electrodes is soldered to a corresponding conductive land on the printed wiring board. On the multilayer ceramic substrate, chip components are mounted as necessary, and in the case where a cavity is provided, a chip component such as a semiconductor element is accommodated in the cavity.

  In order to meet the demand for reduction in size and weight for electronic devices using such a multilayer ceramic substrate, it is desired that the multilayer ceramic substrate also be reduced in size and weight. In order to meet this demand, in order to realize high-density wiring in a multilayer ceramic substrate and to enable high-density wiring, it is necessary to thin the ceramic layer provided in the multilayer ceramic substrate. In order to further advance these high-density wiring and thinning, it is advantageous to use a glass ceramic composition as a material constituting the ceramic layer.

  However, the glass ceramic composition has a lower strength than alumina and the like, and when the multilayer ceramic substrate is thinned or reduced in height as a result of thinning of the ceramic layer, the mounting process to the printed wiring board There is a problem in that cracks are likely to occur due to mechanical or thermal stresses during or after mounting. In particular, the thickness of the multilayer ceramic substrate greatly affects the strength against cracking of the multilayer ceramic substrate when the printed wiring board is bent after mounting using solder. For this reason, it is difficult to reduce the thickness or height of the multilayer ceramic substrate.

In order to improve the strength of the multilayer ceramic substrate, measures such as mixing ceramic fibers with the glass ceramic composition constituting the ceramic layer, lowering the glass / ceramic mixing ratio, and using glass as crystallized glass are also available. Has been taken. However, such a method by adjusting the material composition is relatively troublesome at the design stage for finding the optimum material composition, and may cause undesirable electrical characteristics. There is a problem.
JP 2003-342063 A

  Accordingly, an object of the present invention is to provide a multilayer ceramic electronic component capable of solving the above-described problems.

  The present invention provides a multilayer ceramic electronic comprising a component body having a structure in which a plurality of ceramic layers each extending in a principal surface direction are laminated, and at least two mounting electrodes formed on one principal surface of the component body. The present invention is directed to a component, and is characterized by having the following configuration in order to solve the technical problem described above.

That is, the component main body further includes a stress relaxation electrode formed along a predetermined interface between ceramic layers made of the same material. The stress relieving electrode is positioned so as to face at least the outermost mounting electrode on the main surface, and the mounting electrode is formed opposite to the center in the stacking direction of the component body. It is located at a position closer to the main surface, is exposed to all end faces of the component main body, and has an area larger than the area of the mounting electrodes facing each other.

In the present invention, it is preferable that a plurality of stress relaxation electrodes are formed along the interface between the same ceramic layers.

  Moreover, it is preferable that the stress relaxation electrode extends to a position facing the inner portion of the mounting electrode facing the inner end portion in the main surface direction.

  The thickness of the stress relaxation electrode is preferably 5 μm or more.

  The stress relaxation electrode preferably has a thermal expansion coefficient equivalent to that of the mounting electrode.

  In the present invention, the stress relaxation electrode has a lower elastic modulus than the ceramic layer and has a property of being easily deformed. Further, as described above, the stress relaxation electrode is exposed on the end face of the component main body, and has an area that is equal to or larger than the area of the mounting electrode facing this.

  Therefore, when the printed wiring board is bent in a state in which the multilayer ceramic electronic component is mounted on the printed wiring board via the mounting electrode, the printed circuit board side is more in response to the stress relaxation electrode. The ceramic layer is bent when the bending of the printed wiring board is transmitted through the mounting electrode. However, as described above, the stress relaxation electrode is more easily deformed than the ceramic layer. Since it has, it absorbs stress by deforming in the thickness direction. As a result, the amount of flexure in the ceramic layer on the opposite side of the printed wiring board from the stress relaxation electrode is reduced, making it difficult for the multilayer ceramic electronic component to break, i.e., completely cracked and difficult to break. Can do.

Further, according to the present invention, the stress relaxation electrodes are exposed to all of the end surface of the component main body, it is possible to increase the deformable degree of stress relaxation electrodes, therefore, it corresponds to greater stress Therefore, the lower limit deflection amount that would cause the multilayer ceramic electronic component to be destroyed can be further increased.

  If a plurality of stress relaxation electrodes are formed along the interface between the same ceramic layers, the stress that can be relaxed by the stress relaxation electrodes can be increased. In this case as well, the multilayer ceramic electronic component is destroyed. It is possible to further increase the lower limit deflection amount that leads to the above.

  Regarding the positional relationship between the stress relaxation electrode and the inner end in the main surface direction of the mounting electrode opposite to the stress relaxation electrode, the stress relaxation electrode faces the portion inside the inner end in the main surface direction of the mounting electrode. The area of the stress relaxation electrode is widened, and the amount of deflection at the relatively inner portion in the main surface direction of the multilayer ceramic electronic component can be reduced, and the multilayer ceramic electronic component can be destroyed. It can be made difficult to generate more effectively. In addition, when excessive stress is applied, cracks occur starting from the inner end of the mounting electrode and proceeding in the stacking direction toward the inside of the multilayer ceramic electronic component, but the inner end of the stress relaxation electrode If it is located inside the inner end of the mounting electrode, this crack can be stopped by the stress relaxation electrode. From these things, the effect which suppresses destruction of a multilayer ceramic electronic component can be heightened more.

  When the thickness of the stress relaxation electrode is increased to 5 μm or more, the effect of suppressing the destruction of the multilayer ceramic electronic component can be further ensured.

  When the stress relaxation electrode has a thermal expansion coefficient equivalent to that of the mounting electrode, deformation due to non-uniform compressive stress can be suppressed in the firing step for obtaining the multilayer ceramic electronic component.

  FIG. 1 is a sectional view schematically showing a multilayer ceramic electronic component 1 according to a first embodiment of the present invention. The illustrated multilayer ceramic electronic component 1 constitutes a multilayer ceramic substrate used as a substrate for an oscillator.

  The multilayer ceramic electronic component 1 includes a component body 3 having a structure in which a plurality of insulator ceramic layers 2 each extending in the main surface direction are stacked. The component main body 3 further includes a dielectric ceramic layer 4 as a component of the laminated structure. Capacitor forming electrodes 5 and 6 are formed on one main surface side of the dielectric ceramic layer 4, and the capacitor forming electrodes 5 and 6 are commonly opposed to each other via the dielectric ceramic layer 4. A capacitance forming electrode 7 is formed.

  Several external conductor films 9 and 10 are formed on the upper main surface 8 of the component body 3. At least a part of the external conductor films 9 and 10 is used for electrically connecting a chip component (not shown) to be mounted on the multilayer ceramic electronic component 1.

  A plurality of mounting electrodes 12, 13 and 14 are formed on the lower main surface 11 of the component body 3. These mounting electrodes 12 to 14 are used when the multilayer ceramic electronic component 1 is mounted on a printed wiring board (not shown). For example, by soldering, the mounting electrodes 12 to 14 are electrically connected to the conductive lands on the printed wiring board side. Connected and mechanically fixed.

  Several via-hole conductors 15, 16 and 17 are provided inside the component body 3. The via-hole conductor 15 extends so as to electrically connect the external conductor film 9, the capacitance forming electrode 5, and the mounting electrode 12. The via-hole conductor 16 extends so as to electrically connect the external conductor film 10, the capacitance forming electrode 6, and the mounting electrode 13. The via-hole conductor 17 extends so as to electrically connect the capacitance forming electrode 7 and the mounting electrode 14.

In such a multilayer ceramic electronic component 1, the stress relaxation electrodes 18, 19, 20, and 21, which are the characteristic configuration of the present invention, have predetermined interfaces between the insulating ceramic layers 2 made of the same material provided in the component body 3. It is formed along. Stress relaxation electrodes 18 and 19, the center in the stacking direction of the component body 3, provided closer position to the lower major surface 11 of the component body 3, the stress relaxation electrodes 20 and 21, component body 3 It is provided in the closer position to the upper major surface 8. The stress relaxation electrodes 18 and 19 are formed along the interface between the same insulator ceramic layers 2, and the stress relaxation electrodes 20 and 21 are formed along the interface between the same insulator ceramic layers 2. ing.

The stress relaxation electrodes 18 and 20 are located so as to face the mounting electrode 12 located on the outermost side on the lower main surface 11. In addition, a state in which one end of each of the stress relaxation electrodes 18 and 20 is exposed to the end surface 22 of the component main body 3 is illustrated . Further, the stress relaxation electrodes 18 and 20 have an area that is equal to or larger than the area of the mounting electrode 12 with which they are opposed. Further, each of the stress relaxation electrodes 18 and 20 extends to a position facing the inner portion of the mounting electrode 12 facing the inner end portion in the main surface direction.

Similarly, the stress relaxation electrodes 19 and 21 are located so as to face the mounting electrode 13 located on the outermost side on the lower main surface 11. Further, the stress relaxation electrodes 19 and 21 are illustrated in a state where one end portions of each of the stress relaxation electrodes 19 and 21 are exposed on the end surface 23 of the component main body 3 and have an area that is equal to or larger than the area of the mounting electrode 13 facing each other. ing. In addition, each of the stress relaxation electrodes 19 and 21 extends to a position facing the inner portion of the mounting electrode 13 facing the inner end portion in the main surface direction.

  In the multilayer ceramic electronic component 1 having such a configuration, as an example, the thickness of each of the stress relaxation electrodes 18 to 21 is 5 μm, and the thickness of each of the mounting electrodes 12 to 14 and the external conductor films 9 and 10 is 8 μm. The thickness of each of the capacitance forming electrodes 5 to 7 is 1.5 μm.

  When the multilayer ceramic electronic component 1 is mounted on the printed wiring board (not shown) via the mounting electrodes 12 to 14, when the printed wiring board is bent, the stress relaxation electrode is The insulator ceramic layer 2 below 18 and 19 bends along with the printed wiring board, but the stress relaxation electrodes 18 to 21 absorb stress by being deformed in the thickness direction. Act on. As a result, the amount of bending in the insulator ceramic layer 2 and the dielectric ceramic layer 4 above the stress relaxation electrodes 18 and 19 is reduced, and further, the insulator ceramic layer above the stress relaxation electrodes 20 and 21 is reduced. In the case of 20, the amount of bending is further reduced. For this reason, it is possible to make it difficult for the multilayer ceramic electronic component 1 to be broken.

  As can be seen from the above-described destruction suppressing action of the multilayer ceramic electronic component 1 by the stress relaxation electrodes 18 to 21, the destruction suppressing action by the stress relaxation electrodes 18 and 19 closer to the mounting electrodes 12 to 14 is particularly important. Therefore, the stress relaxation electrodes 20 and 21 provided close to the upper main surface 8 do not have a serious influence even if they are omitted.

  As in this embodiment, when the stress relaxation electrodes are positioned over a plurality of layers, it is possible to cope with a larger stress. Further, the position in the stacking direction in which the stress relaxation electrode is provided can be arbitrarily changed.

  In manufacturing the multilayer ceramic electronic component 1, as is well known, in order to form the via-hole conductors 15 to 17, a process for producing a ceramic green sheet to be each of the insulator ceramic layer 2 and the dielectric ceramic layer 4. A step of providing a through hole in a specific ceramic green sheet and filling the through hole with a conductive paste, capacitance forming electrodes 5 to 7, external conductor films 9 and 10, mounting electrodes 12 to 14, and stress relaxation electrodes 18 to 21. A process of forming a conductive paste on a specific ceramic green sheet by printing to form each of 21, a process of laminating ceramic green sheets according to a predetermined order and pressing in a laminating direction, and laminating A step of firing the raw laminate is performed.

  Although not shown in the drawing, the internal electrodes such as the capacitance forming electrodes 5 to 7, the external conductor films 9 and 10 and the electrodes or conductive films other than the mounting electrodes 12 to 14 and / or the via hole conductors other than the via hole conductors 15 to 17 are used. Further, the conductor may be appropriately formed on a predetermined ceramic green sheet.

The ceramic green sheet to be the insulator ceramic layer 2 described above is obtained by molding a slurry containing ceramic powder and glass powder or a slurry containing ceramic powder into a sheet. For example, alumina powder is used as the ceramic powder. As the glass powder, for example, anorthite crystallized glass powder, cordierite crystallized glass powder, borosilicate glass powder or SiO ₂ —CaO—Al ₂ O ₃ —MgO—B ₂ O ₃ glass powder is used. .

  The ceramic green sheet to be the dielectric ceramic layer 4 is obtained by forming a slurry containing a dielectric ceramic powder into a sheet shape. As the dielectric ceramic powder, for example, barium titanate powder, calcium titanate powder, alumina powder, titania powder or zirconia powder can be used. Moreover, the glass component may be contained in the slurry similarly to the case of the ceramic green sheet for the insulator ceramic layer 2 mentioned above.

  For example, a doctor blade method is applied to form the slurry into a sheet shape in the case of the ceramic green sheet for either the insulator ceramic layer 2 or the dielectric ceramic layer 4. In addition, in order to obtain a green laminate by pre-molding ceramic green sheets, instead of applying a method of laminating a plurality of ceramic green sheets, for example, repeating slurry spraying, roll coating or printing Thus, a raw laminate may be obtained.

  The conductive component contained in the conductive paste used in the method for manufacturing the multilayer ceramic electronic component 1 described above is fired at a temperature applied in the firing step for obtaining the insulator ceramic layer 2 and the dielectric ceramic layer 4. For example, silver, copper, nickel, or the like can be used.

  In particular, with regard to the conductive paste for the stress relaxation electrodes 18 to 21, it is preferable to use a paste having the same composition as the conductive paste for the external conductor films 9 and 10 and the mounting electrodes 12 to 14, for example. Even if they do not have the same composition, it is preferable to use one having at least an equivalent thermal expansion coefficient. Since the thermal expansion coefficient of the insulator ceramic layer 2 sandwiched between the stress relaxation electrodes 18 to 21 and the outer conductor films 9 and 10 and the mounting electrodes 12 to 14 is smaller than the thermal expansion coefficient of both electrodes, When the compressive stress remains, the tensile stress caused by the bending can be offset. Therefore, if the thermal expansion coefficients of the stress relaxation electrodes 18 to 21 and the external conductor films 9 and 10 and the mounting electrodes 12 to 14 are the same, an even compressive stress is applied to the insulator ceramic layer 2, so that the component body 3 can be made difficult to cause.

  The elastic modulus of the stress relaxation electrodes 18 to 21 is substantially the same as that of the outer conductor films 9 and 10 and the mounting electrodes 12 to 14, but compared to the insulator ceramic layer 2 and the dielectric ceramic layer 4. Low. Therefore, as described above, the stress relaxation electrodes 18 to 21 act to absorb stress by being deformed in the thickness direction.

  FIG. 2 is a sectional view schematically showing a multilayer ceramic electronic component 31 according to a second embodiment of the present invention. The illustrated multilayer ceramic electronic component 31 constitutes a multilayer ceramic capacitor.

  The multilayer ceramic electronic component 31 includes a component body 33 having a structure in which a plurality of dielectric ceramic layers 32 extending in the principal surface direction are stacked. The component body 33 also includes first and second capacitance forming electrodes 34 and 35 that face each other with a specific dielectric ceramic layer 32 interposed therebetween. A plurality of sets of first and second capacitance forming electrodes 34 and 35 are provided, and are alternately arranged in the stacking direction of the component main body 33.

  External conductor films 37 and 38 are formed at opposite ends of the upper main surface 36 of the component body 33, respectively. Mounting electrodes 40 and 41 are formed on opposite ends of the lower main surface 39 of the component body 33, respectively. These mounting electrodes 40 and 41 are used when the multilayer ceramic electronic component 31 is mounted on a printed wiring board (not shown). For example, by soldering, the mounting electrodes 40 and 41 are electrically connected to the conductive lands on the printed wiring board side. Connected and mechanically fixed.

  Via hole conductors 42 and 43 are provided inside the component main body 33. The via-hole conductor 42 extends so as to electrically connect the external conductor film 37 and the mounting electrode 40, and is electrically connected to the first capacitance forming electrode 34 at an intermediate portion thereof. The via-hole conductor 43 extends so as to electrically connect the external conductor film 38 and the mounting electrode 41, and is electrically connected to the second capacitance forming electrode 35 at an intermediate portion thereof.

In such a multilayer ceramic electronic component 31, the stress relaxation electrodes 44 and 45, which are a characteristic configuration of the present invention, are formed along a predetermined interface between the dielectric ceramic layers 32 made of the same material provided in the component body 33. Has been. Stress relaxation electrodes 44 and 45, the center in the stacking direction of the component body 33, a closer position to the lower major surface 39 of the component body 33, along the interface between the same dielectric ceramic layer 32 Is formed.

One stress relaxation electrode 44 is positioned so as to face the mounting electrode 40. Further, the state where one end portion of the stress relaxation electrode 44 is exposed to the end face 46 of the component main body 33 is illustrated . Further, the stress relaxation electrode 44 has an area larger than the area of the mounting electrode 40. Further, the stress relaxation electrode 44 extends to a position facing an inner portion of the mounting electrode 40 from the inner end portion in the main surface direction.

Similarly, the other stress relaxation electrode 45 is positioned so as to face the mounting electrode 41. Further, the stress relaxation electrode 45 is shown in a state where one end thereof is exposed to the end surface 47 of the component main body 33, and has an area larger than the area of the mounting electrode 41. Further, the stress relaxation electrode 45 extends to a position facing the inner portion of the mounting electrode 41 from the inner end in the main surface direction.

  When the multilayer ceramic electronic component 31 having such a configuration is mounted on a printed wiring board (not shown) via the mounting electrodes 40 and 41, when the printed wiring board is bent, the multilayer ceramic electronic component 31 is accordingly responded. The dielectric ceramic layer 32 below the stress relaxation electrodes 44 and 45 bends along with the printed wiring board, but the stress relaxation electrodes 44 and 45 absorb stress by being deformed in the thickness direction. Acts like As a result, the amount of deflection in the dielectric ceramic layer 32 above the stress relaxation electrodes 44 and 45 can be reduced, and the multilayer ceramic electronic component 31 can be made less likely to be broken.

  In the multilayer ceramic electronic component 31, the stress relaxation electrode may be formed over a plurality of layers. In particular, when another set of stress relaxation electrodes is formed at positions symmetrical with respect to the illustrated stress relaxation electrodes 44 and 45, the external conductor films 37 and 38 and the mounting electrodes 40 and 41 are respectively provided. Can be reversed, and the direction of the laminated ceramic electronic component in the vertical direction during mounting can be eliminated.

  FIG. 3 is a diagram for explaining various examples of the arrangement of the stress relaxation electrode with respect to the mounting electrode. FIG. 3 shows a view of the multilayer ceramic electronic component 51 as viewed from below. More specifically, (A) shows the lower main surface 53 of the component main body 52, and (B-1) to (B-6) show cross sections through which the stress relaxation electrodes in the component main body 52 pass. ing.

  First, as illustrated in FIG. 3A, the multilayer ceramic electronic component 51 includes twelve mounting electrodes 54 to 65 formed on the lower main surface 53 of the component main body 52. These mounting electrodes 54 to 65 are arranged along the peripheral edge of the lower main surface 53. 3B to 3B, the mounting electrodes 54 to 65 described above are indicated by broken lines.

  In the example shown in FIG. 3B-1, the stress relaxation electrodes 66 and 67 are opposed to the mounting electrodes 54, 58, 61 and 65 located at the corners on the lower main surface 53. , 68 and 69 are arranged.

  In the example shown in FIG. 3B-2, each of the mounting electrodes 55 to 57, 59, 60, and 62 to 64 in addition to the stress relaxation electrodes 66 to 69 shown in FIG. The stress relaxation electrodes 70 to 77 are arranged so as to oppose each other.

  In the example shown in FIG. 3 (B-3), mounting electrodes 54 and 55, mounting electrodes 57 and 58, mounting electrodes 61 and 58 arranged along the long side of the lower main surface 53 of the component body 52, and Longitudinal stress relaxation electrodes 78, 79, 80 and 81 are arranged so as to face 62 and mounting electrodes 64 and 65, respectively.

  In the example shown in FIG. 3B-4, the mounting electrodes 54, 59 and 61 and the mounting electrodes 58, 60 and 65 arranged along the short side of the lower main surface 53 of the component main body 52 are respectively provided. Longitudinal stress relaxation electrodes 82 and 83 are arranged so as to face each other.

  In the example shown in FIG. 3 (B-5), the mounting electrodes 54, 55, 59, 61 and 62 and the mounting electrodes 57, 58 located on the end side in the longitudinal direction of the lower main surface 53 of the component body 52 are used. , 60, 64 and 65 are arranged so as to oppose stress relief electrodes 84 and 85, respectively.

  In the example shown in FIG. 3 (B-6), one stress relaxation electrode 86 is disposed so as to face all of the mounting electrodes 54 to 65 in common. The stress relaxation electrode 86 is formed only in the peripheral region of the component main body 52. Such a formation mode is sufficient in terms of the stress relaxation action of the stress relaxation electrode 86, but the stress relaxation electrode 86 may be formed over the entire predetermined cross section of the component main body 52.

  The stress relaxation electrode shown in FIG. 3 is exposed on all end faces 87 to 90 of the component main body 52 in any of the examples (B-1) to (B-6). Further, the stress relaxation electrode extends to a position facing the inner portion of the mounting electrode opposed to the inner end portion in the main surface direction.

The stress relaxation electrode is positioned so as to face at least the outermost mounting electrode on the main surface of the component main body, and is exposed on all end surfaces of the component main body, and this is the mounting electrode facing this Therefore, an arrangement other than those shown in FIGS. 3B-1 to 3B-6 is also possible.

  Next, experimental examples carried out to confirm the effects of the present invention will be described.

  In this experimental example, when schematically explained, a multilayer ceramic electronic component 101 having a basic structure as shown in cross section in FIG. 4 was produced.

  The multilayer ceramic electronic component 101 includes a component body 103 having a structure in which a plurality of ceramic layers 102 each extending in the principal surface direction are stacked. Three mounting electrodes 105, 106 and 107 are formed on the lower main surface 104 of the component main body 103. The shape and arrangement of the mounting electrodes 105 to 107 will be described later with reference to FIG.

  The component main body 103 includes a stress relaxation electrode 108 formed along a predetermined interface between the ceramic layers 102. The form of the stress relaxation electrode 108 shown in FIG. 4 is merely an example. In this experimental example, as shown in Table 1, the shape of the stress relaxation electrode 108, from the lower principal surface 104 to the stress relaxation electrode 108, is shown. Samples having different dimensions t and thicknesses of the stress relaxation electrode 108 were prepared.

  The symbols “a” to “d” shown in the column of “stress relaxation electrode shape” in Table 1 correspond to (a) to (d) of FIG. The details of various shapes of the stress relaxation electrode 108 shown in FIG. 6 will be described later in relation to the shapes of the mounting electrodes 105 to 107 described below with reference to FIG.

  FIG. 5 shows a lower main surface 104 of a component main body 103 included in the multilayer ceramic electronic component 101. On the lower main surface 104, the mounting electrodes 105 to 107 are formed with the shape and arrangement shown in FIG. In FIG. 5, the unit of the numerical value indicating the dimension is “mm”. In FIG. 6 and FIG. 7 to be described later, the unit of the numerical value indicating the dimension is “mm”.

  Details of the shape of the stress relaxation electrode 108 will be described with reference to FIG.

  The stress relieving electrode 108 shown in FIG. 6A is formed over the entire surface of a predetermined cross section of the component main body 103. As a matter of course, the stress relaxation electrode 108 is positioned so as to face the mounting electrodes 105 to 107, is exposed to the end face of the component main body 103, and the mounting electrodes 105 to 107 facing this. The condition of having an area greater than or equal to is satisfied. Further, the stress relaxation electrode 108 is exposed to all end faces of the component main body 103, and the stress relaxation electrode 108 is an inner end portion in the main surface direction of the mounting electrodes 105 to 107 facing each other. The condition of extending to a position facing the inner part is satisfied.

  Note that the stress relaxation electrode being exposed at the end surface of the component body means that the stress relaxation electrode is completely exposed at the predetermined end surface of the component body, and the end portion is positioned even slightly inside the end surface. What you are doing is not exposed.

  The stress relaxation electrode 108 shown in FIG. 6B is divided into portions facing the mounting electrodes 105 to 107, respectively. However, the stress relaxation electrode 108 shown in FIG. 6B does not satisfy at least the condition that it is exposed to the end face of the component main body 103. Therefore, as will be described later, it is not possible to suppress the destruction of the ceramic electronic component.

  The stress relaxation electrode 108 shown in FIG. 6C is divided into portions facing the mounting electrodes 105 to 107, respectively. As can be understood by referring to FIG. 5 together, the stress relaxation electrode 108 is positioned so as to face the mounting electrodes 105 to 107, is exposed to the end face of the component main body 103, and these are opposed to each other. In addition to the condition that the area is equal to or larger than the area of the mounting electrodes 105 to 107, the condition that all the end faces of the component main body 103 are exposed is satisfied.

  The stress relaxation electrode 108 shown in FIG. 6D is divided into portions facing the mounting electrodes 105 to 107, respectively. The stress relieving electrode 108 shown in FIG. 6D is positioned so as to face the mounting electrodes 105 to 107 as in the case of the stress relieving electrode 108 shown in FIG. In addition to satisfying the condition that all the end faces of the component main body 103 are exposed and the area of the mounting electrodes 105 to 107 being equal to or larger than the area of the mounting electrodes 105 to 107 facing each other, the stress relaxation electrode 108 The condition that the electrodes 105 to 107 extend to a position facing the inner portion from the inner end portion in the main surface direction is satisfied.

  In order to produce the multilayer ceramic electronic component 101 according to each sample as described above, the following steps were performed.

  First, in order to produce a ceramic green sheet to be the ceramic layer 102 of the component main body 103 provided in the multilayer ceramic electronic component 101 as a sample, the following steps were performed.

60 parts by weight of SiO ₂ —CaO—Al ₂ O ₃ —MgO—B ₂ O ₃ glass powder having an average particle size of about 4 μm, 40 parts by weight of alumina powder having an average particle size of about 0.5 μm, and water as a dispersion medium 50 parts by weight, 20 parts by weight of polyvinyl alcohol as a binder, and 1 part by weight of a polycarboxylic acid dispersant are mixed to form a slurry. After removing air bubbles from the slurry, the slurry is formed into a sheet by a doctor blade method. The ceramic green sheet having a predetermined thickness was obtained by molding and then drying. The thickness of the ceramic green sheet was adjusted according to the sample to be obtained so as to conform to the “dimension t” in Table 1 above.

  On the other hand, as a conductive paste for forming the mounting electrodes 105 to 107 and the stress relaxation electrode 108, 48 parts by weight of silver powder having an average particle diameter of about 2 μm, 3 parts by weight of ethyl cellulose as a binder, and as a solvent A solution containing 49 parts by weight of a terpene solvent was prepared.

  Next, using the conductive paste, a plurality of ceramic green sheets including a ceramic green sheet on which the stress relaxation electrode 108 is printed with any of the shapes shown in FIGS. Further, mounting electrodes 105 to 107 were formed on the outer surface of the outermost ceramic green sheet by printing. As shown in Table 1, regarding the stress relaxation electrode 108, not only the above-described shape but also the dimension t and thickness were varied depending on the sample. In Comparative Example 1, the stress relaxation electrode 108 was not formed.

  Next, the raw laminate obtained as described above is cut to have a planar size of 3.2 mm × 1.3 mm after firing, and then fired at a temperature of 880 ° C. for 30 minutes. The multilayer ceramic electronic component 101 according to each sample was obtained. The obtained multilayer ceramic electronic component 101 had a thickness of 200 μm.

  Next, the multilayer ceramic electronic component 101 according to each sample was mounted on a printed wiring board 109 as shown in FIG. 7 by a solder reflow method. FIG. 7 is a plan view showing a part of the printed wiring board 109. In FIG. 7, the multilayer ceramic electronic component 101 is indicated by a broken line. As shown in FIG. 7, the printed wiring board 109 includes conductive lands 110, 111, and 112 corresponding to the mounting electrodes 105, 106, and 107 included in the multilayer ceramic electronic component 101, respectively. The thickness of the printed circuit board 109 was 1.6 mm.

  Next, the printed wiring board 109 on which the multilayer ceramic electronic component 101 was mounted as described above was placed on a support base providing two fulcrums 113 and 114 having a span S of 90 mm as shown in FIG. At this time, the side on which the multilayer ceramic electronic component 101 was mounted was made to face downward.

  Next, the printed wiring board 109 is pressed downward at the center between the fulcrums 113 and 114 as indicated by an arrow 115 to bend the printed wiring board 109, and the amount of bending and the multilayer ceramic electronic component 101 can occur. The relationship with destruction was investigated.

  More specifically, when the amount of bending is expressed as the amount of displacement in the direction of arrow 115 at the center of the printed wiring board 109, this is expressed as 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, and 2. For each of the ten samples, whether or not the multilayer ceramic electronic component 101 is broken at each strain amount while increasing in steps such as 5 mm, 3.0 mm, 3.5 mm, and 4.0 mm. evaluated. The destruction of the multilayer ceramic electronic component 101 means a state in which the multilayer ceramic electronic component 101 is completely cracked and divided.

  The “minimum amount of bending at which breakage occurs” shown in Table 1 above is the amount of bending that was given when at least one sample was broken when the amount of bending of the printed wiring board 109 was increased stepwise. Show.

  In this experimental example, the fracture occurrence rate was also evaluated. The fracture occurrence rate is a ratio indicating how many of the 10 samples were broken under the condition of each deflection amount increased stepwise, and this was expressed as a percentage.

  Comparing the “destructive minimum deflection amount” shown in Table 1, the results are superior to those of Comparative Examples 1 and 2 according to Examples 1-3 and 5-8. In the following, Examples 1 to 8 and Comparative Examples 1 and 2 are compared with each other.

  FIG. 9 is a diagram illustrating the relationship between the amount of deflection and the failure occurrence rate for Examples 1 to 3 and Comparative Example 1.

  Referring to FIG. 9, Examples 1 to 3 have not only “destructive minimum deflection amount” larger than Comparative Example 1, but also a lower failure occurrence rate.

  Further, when comparing between Examples 1 to 3, Examples 1 to 3 have the same “stress relaxation electrode shape” and “stress relaxation electrode thickness” as shown in Table 1, and “dimension t Only is different. In Example 1, the “minimum amount of occurrence of fracture” is larger than in Examples 2 and 3, and excellent results are obtained. On the other hand, Examples 2 and 3 have the same “1.0 mm” with respect to the “minimum amount of occurrence of breakage”. From this, it can be seen that when the stress relaxation electrode is provided at a position close to the mounting electrode, it is possible to increase the “minimum amount of bending at which fracture occurs”.

  FIG. 10 is a diagram showing the relationship between the amount of deflection and the failure occurrence rate for Examples 2 and 4 to 6 and Comparative Example 1.

  Referring to FIG. 10, according to Examples 2 and 4 to 6, the fracture occurrence rate is lower than that of Comparative Example 1. Here, in particular, when Example 4 and Comparative Example 1 are compared with each other, the “destructive minimum deflection amount” shown in Table 1 is shown in FIG. Comparing the indicated failure occurrence rates, the failure occurrence rate is 40% in Example 4 and 70% in Comparative Example 1 at a deflection amount of 1.0 mm. That is, it can be seen that Example 4 has a lower rate of destruction and is less likely to break than Comparative Example 1.

  Further, when comparing between Examples 2 and 4 to 6, as shown in Table 1, these samples differed in “thickness of stress relaxation electrode”, and in the order of Examples 4, 2, 5, and 6. It is thicker. This is reflected in the “minimum occurrence amount of fracture occurrence” shown in Table 1. As the “stress relaxation electrode thickness” becomes thicker, the “minimum occurrence amount of fracture occurrence” becomes larger. Also, the “stress relaxation electrode thickness” has an influence on the failure occurrence rate shown in FIG. That is, as the “stress relaxation electrode thickness” becomes thicker, the fracture occurrence rate tends to be lower.

  In particular, as in Examples 2, 5 and 6, when “stress relaxation electrode thickness” is 5 μm or more, better results were obtained for both “minimum amount of occurrence of fracture” and fracture rate. Yes.

  Further, the “stress relaxation electrode shape” shown in Table 1 is compared. As shown in Table 1, Examples 2, 7 and 8 have the same “dimension t” and “stress relaxation electrode thickness” but different “stress relaxation electrode shapes”. However, even if the “stress relaxation electrode shape” is different, the “destructive minimum deflection amount” is the same. Therefore, as far as Table 1 is seen, it is impossible to find the difference due to the “stress relaxation electrode shape”.

  Therefore, when the failure occurrence rate under the deflection amount of 1.5 mm that is the “minimum deflection amount at which fracture occurs” is compared, in Example 2, it is 30% as shown in FIG. In Example 7, it was 50%, and in Example 8, it was 40%. From these facts, it can be seen that superior results were obtained in the order of Examples 7, 8, and 2 in terms of the effect of preventing destruction. In other words, with regard to the “stress relaxation electrode shape”, it can be seen that (a) shown in FIG. 6 is the best, followed by (d) and (c) in this order.

  Further, when attention is paid to Comparative Example 2, as shown in Table 1, the “stress relaxation electrode shape” is (b) shown in FIG. 6, and the stress relaxation electrode 108 is formed on any end face of the component main body 103. Not exposed. Thus, even if the stress relaxation electrode 108 is provided, if it is not exposed at any end face of the component main body 103, the stress relaxation electrode 108 is provided as shown in Table 1. It has been confirmed that the comparative example 1 and the “minimum amount of occurrence of breakage” do not change, and the breakage occurrence rate is not substantially improved at all.

1 is a cross-sectional view schematically showing a multilayer ceramic electronic component 1 according to a first embodiment of the present invention. It is sectional drawing which shows schematically the multilayer ceramic electronic component 31 by 2nd Embodiment of this invention. It is the figure which looked at the multilayer ceramic electronic component 51 from the bottom which shows some examples about arrangement | positioning of the electrode for stress relaxation with respect to the electrode for mounting which can be applied in this invention. It is sectional drawing which shows the basic structure of the multilayer ceramic electronic component 101 produced in the experiment example schematically. FIG. 5 is a view showing the multilayer ceramic electronic component 101 shown in FIG. 4 from the lower main surface 104 side of the component main body 103. It is a figure which shows four types of shapes about the electrode 108 for stress relaxation employ | adopted in the experiment example. It is a top view which shows a part of printed wiring board 109 used in the experiment example. It is a figure for demonstrating operation which bends the printed wiring board 109 in order to evaluate destruction of the multilayer ceramic electronic component 101 in an experiment example. It is a figure which shows the relationship between the amount of bending, and the failure occurrence rate about Examples 1-3 produced in the experiment example, and the comparative example 1. FIG. It is a figure which shows the relationship between the deflection amount and the failure occurrence rate about Example 2 and 4-6 produced in the experiment example, and the comparative example 1. FIG.

Explanation of symbols

1, 31, 51, 101 Multilayer ceramic electronic component 2 Insulator ceramic layer 3, 33, 52, 103 Component body 4, 32 Dielectric ceramic layer 8, 11, 36, 39, 53, 104 Main surface 12-14, 40 , 41, 54 to 65, 105 to 107 Mounting electrodes 18 to 21, 44, 45, 66 to 86, 108 Stress relief electrodes 22, 23, 46, 47, 87 to 90 End face 102 Ceramic layer 109 Printed wiring board

Claims (5)

A multilayer ceramic electronic component comprising: a component main body having a structure in which a plurality of ceramic layers each extending in a main surface direction are laminated; and at least two mounting electrodes formed on one main surface of the component main body. And
The component body further includes a stress relaxation electrode formed along a predetermined interface between the ceramic layers made of the same material,
The stress relieving electrode is positioned so as to face at least the outermost mounting electrode on the main surface, and is opposed to the center of the component main body in the stacking direction. A multilayer ceramic electronic component located at a position closer to the main surface on which an electrode is formed, exposed to all end surfaces of the component body, and having an area equal to or larger than an area of the mounting electrode facing the main body. The multilayer ceramic electronic component according to claim 1, wherein the plurality of stress relaxation electrodes are formed along an interface between the same ceramic layers. 3. The multilayer ceramic electronic component according to claim 1, wherein the stress relaxation electrode extends to a position facing an inner portion of the mounting electrode facing the inner end portion in the main surface direction. 4. . The thickness of the stress relaxation electrodes is 5μm or more, the laminated ceramic electronic component according to any of claims 1 to 3. It said stress relaxation electrodes has a thermal expansion coefficient equivalent to that of the mounting electrode, the laminated ceramic electronic component according to any of claims 1 to 4.

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