Multilayer capacitors

Abstract

The stacked capacitor comprises: a body having a pair of end faces opposite to each other and a pair of side faces and a pair of main faces located between the pair of end faces and extending in a first direction opposite to the pair of end faces; a pair of external electrodes arranged on the pair of end faces, the body comprising: an inner layer portion, in which a plurality of internal electrodes and a plurality of dielectric layers are stacked on each other in a second direction in which the pair of main faces are opposite to each other; a pair of outer layer portions, which are arranged on the outside in the second direction relative to the inner layer portion, and on at least one of the pair of end faces, the internal electrode of the inner layer portion protrudes outward in the first direction by a predetermined protrusion amount compared to the outer layer portion, and the ratio of the protrusion amount to the dimension of the outer layer portion in the second direction on one side is 96000ppm to 176000ppm.

Description

Technical Field

[0001] The present invention relates to a stacked capacitor. Background Art

[0002] A known multilayer capacitor includes: a body having a pair of end faces facing each other, a pair of side faces and a pair of main faces located between the pair of end faces and extending in a longitudinal direction facing the pair of end faces; and a pair of external electrodes disposed on the pair of end faces (for example, see Japanese Patent Publication No. 2003-318060). This multilayer capacitor includes an inner layer portion having internal electrodes stacked thereon and an outer layer portion sandwiching the inner layer portion. Summary of the invention

[0003] Here, in the above-mentioned multilayer capacitor, the internal electrode of the inner layer portion sometimes protrudes outward in the length direction by a predetermined amount relative to the outer layer portion. This protrusion amount may affect the performance of the multilayer capacitor, and therefore, it is required to improve the performance of the multilayer capacitor by adjusting the protrusion amount to an appropriate range.

[0004] Therefore, an object of the present invention is to provide a multilayer capacitor having improved performance.

[0005] The stacked capacitor comprises: an element body having a pair of end faces opposite to each other and a pair of side faces and a pair of main faces located between the pair of end faces and extending in a first direction opposite to the pair of end faces; a pair of external electrodes arranged on the pair of end faces, the element body having an inner layer portion in which a plurality of internal electrodes and a plurality of dielectric layers are stacked on each other in a second direction opposite to the pair of main faces, and a pair of outer layer portions arranged on the outer side in the second direction relative to the inner layer portion, in at least one of the pair of end faces, the internal electrode of the inner layer portion protrudes outward in the first direction by a predetermined protrusion amount compared to the outer layer portion, and the ratio of the protrusion amount to the dimension of the outer layer portion in the second direction on one side is 96000ppm to 176000ppm.

[0006] If the protrusion is too large, the possibility of cracks increases. On the other hand, if the protrusion is too small, the deviation of the electrostatic capacitance may be affected due to poor contact between the internal electrode and the external electrode. In contrast, the inventors of the present invention conducted in-depth research and found that there is a correlation between the ratio of the protrusion to the dimension of the second direction of the outer layer of one side and the performance of the stacked capacitor, and found an appropriate range. Specifically, by setting the ratio of the protrusion to the dimension of the second direction of the outer layer of one side to less than 176000ppm, cracks can be suppressed. In addition, by setting the ratio of the protrusion to the dimension of the second direction of the outer layer of one side to more than 96000ppm, the deviation of the electrostatic capacitance can be suppressed. As above, the performance of the stacked capacitor can be improved.

[0007] The ratio may be 165000 ppm or less, or 154000 ppm or less. In this case, cracking can be further suppressed.

[0008] The ratio may be 121000 ppm or more, or 137000 ppm or more. In this case, the variation in electrostatic capacitance can be further reduced.

[0009] Alternatively, the internal electrode may include a main electrode portion that forms an electrostatic capacitor and a connecting portion that connects the main electrode portion to the external electrode, and in a third direction in which a pair of side surfaces are opposite, the width dimension of the connecting portion is smaller than the width dimension of the main electrode portion. In this case, the infiltration of the plating solution near the connecting portion can be suppressed, but on the other hand, cracks and deviations in electrostatic capacitance are likely to occur. In contrast, by setting the ratio to the above range, the infiltration of the plating solution can be suppressed and the deviations in cracks and electrostatic capacitance can be suppressed.

[0010] According to the present invention, a multilayer capacitor having improved performance can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a perspective view showing a multilayer capacitor according to an embodiment of the present invention.

[0012] Figure 2 It is a diagram for explaining the cross-sectional structure of the multilayer capacitor in accordance with the present embodiment.

[0013] Figure 3 It is a diagram for explaining the cross-sectional structure of the multilayer capacitor in accordance with the present embodiment.

[0014] Figure 4 It is a diagram for explaining the cross-sectional structure of the multilayer capacitor in accordance with the present embodiment.

[0015] Figure 5 This is an enlarged cross-sectional view near the end surface.

[0016] Figure 6 This is a table showing experimental conditions and measurement results.

[0017] Figure 7 It is a graph showing the measurement results.

[0018] Figure 8 It is a graph showing the measurement results.

[0019] Explanation of symbols

[0020] 2 ... element body, 5, 7 ... external electrodes, 11, 13 ... internal electrodes, 11a, 13a ... main electrode portion, 11b, 13b ... connecting portion, 20 ... inner layer portion, 22 ... outer layer portion, C1 ... multilayer capacitor. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same functions, and repeated descriptions are omitted.

[0022] Reference Figure 1 to Figure 3 , the structure of the multilayer capacitor C1 according to the present embodiment will be described. Figure 1 It is a perspective view showing a multilayer capacitor according to the present embodiment. Figure 2 and Figure 3 1 and 2 are diagrams for explaining the cross-sectional structure of the multilayer capacitor according to the present embodiment. In the present embodiment, a multilayer capacitor C1 is described as an example of an electronic component.

[0023] like Figure 1 As shown, the multilayer capacitor C1 includes a rectangular parallelepiped element body 2 and external electrodes 5 and 7 arranged on the outer surface of the element body 2. The external electrodes 5 and 7 are separated. The rectangular parallelepiped shape includes a rectangular parallelepiped shape with chamfered corners and ridges and a rectangular parallelepiped shape with rounded corners and ridges. The external electrodes 5 and 7 are also terminal electrodes.

[0024] The element body 2 has a pair of end faces 2a and 2b facing each other, a pair of main faces 2c and 2d facing each other, and a pair of side faces 2e and 2f facing each other as its outer surface. In this embodiment, the direction in which the pair of end faces 2a and 2b face each other (the first direction D1) is the length direction of the element body 2, the direction in which the pair of main faces 2c and 2d face each other (the second direction D2) is the height direction of the element body 2, and the direction in which the pair of side faces 2e and 2f face each other (the third direction D3) is the width direction of the element body 2.

[0025] The length of the first direction D1 of the element body 2 is greater than the length of the second direction D2 of the element body 2 and the length of the third direction D3 of the element body 2. The length of the second direction D2 of the element body 2 and the length of the third direction D3 of the element body 2 are equal. That is, in the present embodiment, a pair of end faces 2a, 2b are square, and a pair of main faces 2c, 2d and a pair of side faces 2e, 2f are rectangular. The length of the first direction D1 of the element body 2 may also be equal to the length of the second direction D2 of the element body 2 and the length of the third direction D3 of the element body 2. The length of the second direction D2 of the element body 2 and the length of the third direction D3 of the element body 2 may also be different.

[0026] The term "equal" may include values ​​that include a slight difference or manufacturing error within a predetermined range, in addition to being equal. For example, if a plurality of values ​​are within a range of ±5% of the average value of the plurality of values, the plurality of values ​​are defined as being equal.

[0027] The pair of main surfaces 2c and 2d extend in the first direction D1 so as to connect the pair of end surfaces 2a and 2b. The pair of main surfaces 2c and 2d also extend in the third direction D3. The pair of side surfaces 2e and 2f extend in the first direction D1 so as to connect the pair of end surfaces 2a and 2b. The pair of side surfaces 2e and 2f also extend in the second direction D2.

[0028] The element body 2 is formed by stacking a plurality of dielectric layers 21 in a direction (second direction D2) in which a pair of main surfaces 2c and 2d are opposite to each other. In the element body 2, the stacking direction of the plurality of dielectric layers 21 (hereinafter referred to as the "stacking direction") is consistent with the second direction D2. Each dielectric layer 21 is composed of, for example, a sintered body of a ceramic green sheet containing a dielectric material (a dielectric ceramic of BaTiO3 system, Ba(Ti, Zr)O3 system, or (Ba, Ca)TiO3 system). In the actual element body 2, each dielectric layer 21 is integrated to such an extent that the boundaries between the dielectric layers 21 cannot be identified. The third direction D3 may also be the above-mentioned stacking direction.

[0029] Thus, the element body 2 has an inner layer portion 20 in which a plurality of internal electrodes 11, a plurality of internal electrodes 13, and a plurality of dielectric layers 21 are stacked one on another in the second direction D2. In addition, the element body 2 has a pair of outer layer portions 22 arranged on the outer side of the inner layer portion 20 in the second direction D2. Thus, the inner layer portion 20 is sandwiched by the pair of outer layer portions 22 in the second direction D2. In addition, the material constituting the outer layer portion 22 may be different from the material constituting the inner layer portion 20. In different cases, in the present embodiment, the generation of cracks caused by the difference in thermal shrinkage between the inner layer portion 20 and the outer layer portion 22 can be suppressed, so the effect becomes significant. Alternatively, the outer layer portion 22 may be composed of the same material as the inner layer portion 20. Even if the outer layer portion 22 and the inner layer portion 20 are made of the same material, the structure such as the thickness of the sheet and the presence or absence of electrodes sometimes contributes to the difference in shrinkage between the outer layer portion 22 and the inner layer portion 20.

[0030] like Figure 2 and Figure 3 As shown, the multilayer capacitor C1 includes a plurality of internal electrodes 11 and a plurality of internal electrodes 13. The internal electrodes 11 and 13 are made of a conductive material (e.g., Ni or Cu) commonly used as an internal conductor of a multilayer electronic component. The internal electrodes 11 and 13 are made of a sintered body of a conductive paste containing the conductive material. The internal electrodes 11 and 13 function as internal conductors arranged in the element body 2.

[0031] The internal electrodes 11 and 13 are arranged at different positions (layers) in the second direction D2. That is, the internal electrodes 11 and 13 are alternately arranged in the element body 2 to face each other with a gap in the second direction D2. The internal electrodes 11 and 13 have different polarities.

[0032] like Figure 3 As shown, each internal electrode 11 includes a main electrode portion 11a and a connecting portion 11b. The main electrode portion 11a is a portion that forms an electrostatic capacitor by being opposite to the main electrode portion 13a of the internal electrode 13 described below. The connecting portion 11b is a portion that connects the main electrode portion 11a and the external electrode 5. The connecting portion 11b extends from one side (one short side) of the main electrode portion 11a and is exposed at the end face 2a. The internal electrode 11 is exposed at the end face 2a, and is not exposed at the end face 2b, a pair of main faces 2c, 2d, and a pair of side faces 2e, 2f. The main electrode portion 11a and the connecting portion 11b are formed integrally.

[0033] The main electrode portion 11a has a rectangular shape with the first direction D1 as the long side direction and the third direction D3 as the short side direction. That is, the length of the main electrode portion 11a of each internal electrode 11 in the first direction D1 is greater than the length in the third direction D3. The connecting portion 11b extends from the end portion on the end face 2a side of the main electrode portion 11a to the end face 2a. The length of the connecting portion 11b in the first direction D1 is smaller than the length of the main electrode portion 11a in the first direction D1. The length of the connecting portion 11b in the third direction D3 is equal to the length of the main electrode portion 11a in the third direction D3. The connecting portion 11b is connected to the external electrode 5 at the end portion exposed at the end face 2a. The length of the connecting portion 11b in the third direction D3 may be smaller than the length of the main electrode portion 11a in the third direction D3.

[0034] like Figure 3 As shown, each internal electrode 13 includes a main electrode portion 13a and a connecting portion 13b. The main electrode portion 13a is a portion that forms an electrostatic capacitor by being opposite to the main electrode portion 11a of the internal electrode 11 described below. The connecting portion 13b is a portion that connects the main electrode portion 13a and the external electrode 7. The main electrode portion 13a is opposite to the main electrode portion 11a via a portion (dielectric layer) of the element body 2 in the second direction D2. The connecting portion 13b extends from one side (one short side) of the main electrode portion 13a and is exposed at the end face 2b. The internal electrode 13 is exposed at the end face 2b, and is not exposed at the end face 2a, a pair of main faces 2c, 2d, and a pair of side faces 2e, 2f. The main electrode portion 13a and the connecting portion 13b are formed integrally.

[0035] The main electrode portion 13a is in a rectangular shape with the first direction D1 as the long side direction and the third direction D3 as the short side direction. That is, the length of the main electrode portion 13a in the first direction D1 of each internal electrode 13 is greater than the length in the third direction D3. The connecting portion 13b extends from the end portion on the end face 2b side of the main electrode portion 13a to the end face 2b. The length of the connecting portion 13b in the first direction D1 is smaller than the length of the main electrode portion 13a in the first direction D1. The length of the connecting portion 13b in the third direction D3 is equal to the length of the main electrode portion 13a in the third direction D3. The connecting portion 13b is connected to the external electrode 7 at the end portion exposed at the end face 2b. The length of the connecting portion 13b in the third direction D3 may be smaller than the length of the main electrode portion 13a in the third direction D3.

[0036] In addition, the internal electrodes 11 and 13 may also have Figure 4 Shape shown. Figure 4 The internal electrodes 11 and 13 shown have a shape in which the connecting portions 11b and 13b are narrowed relative to the main electrode portions 11a and 13a. Thus, in the third direction D3, the width dimension of the connecting portion 11b is smaller than the width dimension of the main electrode portion 11a. In the third direction D3, the width dimension of the connecting portion 13b is smaller than the width dimension of the main electrode portion 13a.

[0037] When viewed in the first direction D1, the external electrode 5 is located at the end portion of the end surface 2a of the element body 2. The external electrode 5 includes an electrode portion 5a located at the end surface 2a, an electrode portion 5b located at a pair of main surfaces 2c and 2d, and an electrode portion 5c located at a pair of side surfaces 2e and 2f. That is, the external electrode 5 is formed on the five surfaces 2a, 2c, 2d, 2e, and 2f.

[0038] The electrode portions 5a, 5b, and 5c adjacent to each other are connected and electrically connected to each other at the ridgeline of the element body 2. The electrode portion 5a and the electrode portion 5b are connected at the ridgeline between the end face 2a and each of the main faces 2c and 2d. The electrode portion 5a and the electrode portion 5c are connected at the ridgeline between the end face 2a and each of the side faces 2e and 2f.

[0039] The electrode portion 5a is arranged to completely cover the portion of each connecting portion 11b exposed at the end surface 2a, and the connecting portion 11b is directly connected to the external electrode 5. That is, the connecting portion 11b connects the main electrode portion 11a and the electrode portion 5c. Thus, each internal electrode 11 is electrically connected to the external electrode 5.

[0040] When viewed in the first direction D1, the external electrode 7 is located at the end portion of the end surface 2b of the element body 2. The external electrode 7 includes an electrode portion 7a located at the end surface 2b, an electrode portion 7b located at a pair of main surfaces 2c and 2d, and an electrode portion 7c located at a pair of side surfaces 2e and 2f. That is, the external electrode 7 is formed on the five surfaces 2b, 2c, 2d, 2e, and 2f.

[0041] The electrode portions 7a, 7b, and 7c adjacent to each other are connected and electrically connected to each other at the ridgeline of the element body 2. The electrode portion 7a and the electrode portion 7b are connected at the ridgeline between the end face 2b and each of the main faces 2c and 2d. The electrode portion 7a and the electrode portion 7c are connected at the ridgeline between the end face 2b and each of the side faces 2e and 2f.

[0042] The electrode portion 7a is arranged to cover all the portions of the connecting portions 13b exposed at the end surface 2b, and the connecting portions 13b are directly connected to the external electrode 7. That is, the connecting portion 13b connects the main electrode portion 13a and the electrode portion 7c. Thus, each internal electrode 13 is electrically connected to the external electrode 7.

[0043] Figure 5 It is an enlarged cross-sectional view near the end face 2a. In addition, Figure 5 In the figure, only one end face 2a is shown, but the following description also applies to the other end face 2b. Figure 5 As shown, the internal electrode 11 of the inner layer portion 20 protrudes outward in the first direction relative to the outer layer portion 22 by a predetermined protrusion amount β. In addition, when setting the reference lines ST1 and ST2 for determining the protrusion amount β, the reference line ST1 is set relative to the outermost portion in the first direction D1 of the end surface 2a on the inner layer portion 20 side. In addition, the reference line ST2 is set relative to the outermost portion in the first direction D1 of the end surface 2a on the outer layer portion 22 side. In addition, the length of the outer layer portion 22 in the first direction D1 is expressed as a dimension α. ​​This dimension α is substantially the same as the dimension L described below.

[0044] Next, the dimensional relationship of the multilayer capacitor C1 is described. Figure 2 As shown, the length of the element body 2 in the first direction D1 is set to dimension L1. The size of the gap in the first direction D1 between the internal electrode 11 and the end face 2b, and the size of the gap in the first direction D1 between the internal electrode 13 and the end face 2a are set to dimension LGap. Dimension L can be set to 370 to 6100 μm, preferably 1450 to 3600 μm. In addition, dimension L is a dimension based on the outermost part of the end faces 2a and 2b in the first direction D1. Dimension LGap can be set to 30 to 280 μm, preferably 100 to 200 μm. In addition, the radius of curvature of the fillet of the corner of the element body 2, that is, dimension R, can be set to 10 to 350 μm, preferably 75 to 200 μm.

[0045] The height of the element body 2 in the second direction D2 is defined as dimension T. The size of the gap in the second direction D2 between the inner layer portion 20 and the main surfaces 2c and 2d, that is, the thickness of the outer layer portion 22 in the second direction D2 is defined as dimension TGap. Dimension T can be set to 170 to 3100 μm, preferably 600 to 2900 μm. Dimension TGap can be set to 20 to 240 μm, preferably 90 to 200 μm.

[0046] like Figure 3 As shown, the width of the element body 2 in the third direction D3 is set to dimension W. The size of the gap in the third direction D3 between the main electrode portions 11a, 13a of the internal electrodes 11, 13 and the side surfaces 2e, 2f is set to dimension WGap. The size of the gap in the third direction D3 between the connecting portions 11b, 13b of the internal electrodes 11, 13 and the side surfaces 2e, 2f is set to dimension W2Gap. In addition, the width of the connecting portions 11b, 13b is set to dimension WD. Dimension W can be set to 170 to 5400 μm, preferably 600 to 2900 μm. Dimension WGap can be set to 30 to 280 μm, preferably 100 to 200 μm. Dimension W2Gap can be set to 30 to 700 μm, preferably 230 to 560 μm.

[0047] like Figure 4 As shown, the thickness of the dielectric layer 21 is set to dimension t1, and the thickness of the internal electrodes 11 and 13 is set to dimension t2. Dimension t1 can be set to 0.6 to 6.5 μm, preferably 1.6 to 2.2 μm. Dimension t2 can be set to 0.6 to 1.2 μm, preferably 0.8 to 1.0 μm.

[0048] Next, the size of the protrusion amount β of the inner layer portion 20 is described. The size of the protrusion amount β is affected by the size of the entire multilayer capacitor C1, etc. Therefore, here, the preferred range of the protrusion amount β is described using the ratio of the protrusion amount β to the size of a specified portion of the multilayer capacitor C1. In addition, the range of the ratio of the protrusion amount β is set to a range that can suppress thermal cracks generated relative to the base of the element body 2 and suppress the deviation of the electrostatic capacitance. In the multilayer capacitor C1, the desired protrusion amount β can be obtained by adjusting the firing conditions such as the maximum temperature during firing, the thickness of the internal electrodes 11 and 13, etc. Therefore, even if the shape and size of the multilayer capacitor C1 are the same, by changing the firing conditions or the thickness of the internal electrodes 11 and 13, etc., it is possible to produce samples with different protrusion amounts β.

[0049] In this specification, the generation of thermal cracks is evaluated as follows. Prepare multiple (for example, 20) samples of stacked capacitors C1 of the same shape and size and with the same protrusion amount β. Then, immerse each sample in a solder bath at 400°C for 3 seconds and take it out. Then, perform a crack resistance test based on thermal stress. Observe each sample after the test and evaluate the ratio of the number of samples that have thermal cracks to the total number. Figure 6 In the "Hot crack" item, this ratio is expressed as %. Figure 7 and Figure 8 In the above, the ratio is represented by "base thermal crack %". In addition, the evaluation method of thermal crack is not necessarily limited to the above method.

[0050] In this specification, the deviation of electrostatic capacitance is evaluated as follows. Prepare multiple (for example, 10) samples of stacked capacitors C1 of the same shape and size and with the same protrusion amount β. Then, measure the electrostatic capacitance of each sample. After obtaining the electrostatic capacitance of all samples, calculate the average value. Then, calculate the CV value by dividing the standard deviation by the average value, and evaluate the CV value as the deviation. Figure 6 In the “Capacitance” field, this value is indicated by Figure 7 and Figure 8 In FIG. 5 , this value is represented by “electrostatic capacitance CV.” In addition, the evaluation method of the variation in electrostatic capacitance is not necessarily limited to the above-mentioned method.

[0051] Specifically, the inventors of the present invention have conducted in-depth research and found that a predetermined relationship exists between the ratio of the protrusion amount β to the dimension T in the second direction D2 of the element body 2 (hereinafter sometimes referred to as the "T ratio") and the occurrence of thermal cracks. In addition, the T ratio is a value obtained by the calculation formula "protrusion amount β / T dimension". Specifically, if Figure 7 As shown in FIG. 1 , in the region with a small T ratio, the base thermal crack is suppressed to 0%. In addition, in the region with a large T ratio, the ratio of base thermal crack increases proportionally along the prescribed approximation line AL1 as the T ratio increases. In the region with a small T ratio, the deviation of the electrostatic capacitance decreases along the prescribed approximation line AL2 as the T ratio increases. In addition, in the region with a large T ratio, the deviation of the electrostatic capacitance converges to a prescribed value ( Figure 7 , CV around 0.008), and is suppressed near this value.

[0052] In addition, the inventors of the present invention have conducted in-depth research and found that a predetermined relationship exists between the ratio of the protrusion amount β to the dimension TGap in the second direction D2 of the outer layer 22 (hereinafter sometimes referred to as the "TGap ratio") and the occurrence of thermal cracks. In addition, the TGap ratio is a value obtained by the calculation formula "protrusion amount β / TGap dimension". Specifically, if Figure 8 As shown, in the area with a small TGap ratio, the base thermal cracks are suppressed to 0%. In addition, in the area with a large TGap ratio, the proportion of base thermal cracks increases proportionally along the prescribed approximate line AL3 as the TGap ratio increases. In the area with a small TGap ratio, the deviation of the electrostatic capacitance decreases along the prescribed approximate line AL4 as the T ratio increases. In addition, in the area with a large TGap ratio, the deviation of the electrostatic capacitance converges to a prescribed value ( Figure 8 , CV around 0.008), and is suppressed near this value.

[0053] Figure 7 and Figure 8 is based on Figure 6 The conditions of the multilayer capacitor C1 are not limited to Figure 6 That is, the numerical range described in this specification is not the absolute value of the protrusion amount β, but a range specified by the ratio of the protrusion amount β. Therefore, even if the conditions of the multilayer capacitor are changed, the relationship of the same meaning is established. Figure 6 In the experiment shown, the protrusion amount β of component A and component B is set to Figure 6 (a) The value shown in the "Protrusion" item. In addition, the value of the above-mentioned "LGap" is shown in the "L" item in the "Gap size" column. The same applies to other items. In addition, regarding component C, for components of the same shape and size of the stacked capacitor, 7 components (components C-1 to C-7) with different protrusion amounts β are prepared. Based on these conditions, the T ratio is calculated and shown in the "T dimension ppm" item in the "Protrusion rate" column. In addition, the TGap ratio is calculated and shown in the "Cover thickness ppm" item in the "Protrusion rate" column. In addition, the ratio of the protrusion amount β to the dimension α of the length of the outer layer 22 in the first direction D1 is shown in the "β / αppm" item. A plurality of components A, component B, and components C-1 to C-7 set to these experimental conditions are prepared, and the base thermal cracks and electrostatic capacitance deviations are measured by the above-mentioned method. The measurement results of the electrostatic capacitance deviation are shown in the "Capacitance value / CV" item, and the measurement results of the base thermal cracks are shown in the "400℃ / Thermal crack" item. In addition, Figure 6 In (b), the thickness dimension t1 of the dielectric layer 21 is indicated as "BT thickness t1", the thickness dimension t2 of the internal electrodes 11 and 13 is indicated as "electrode thickness t2", and the number of layers of the internal electrodes 11 and 13 is indicated in the item "Number of layers". In addition, as the material of the dielectric layer 21 of the inner layer portion 20 of each component, barium titanate, calcium titanate, strontium titanate, etc. are used as the main component, and as the material of the outer layer portion 22, barium titanate, calcium titanate, strontium titanate, etc. are used as the main component.

[0054] Specifically, the T ratio is preferably 11000 ppm to 16000 ppm. In addition, the T ratio is more preferably 15000 ppm or less, and further preferably 14000 ppm or less. In addition, the T ratio is more preferably 12000 ppm or more, and further preferably 12500 ppm or more.

[0055] In the multilayer capacitor C1, it is preferred to suppress the occurrence of base thermal cracks to 20% or less. In this regard, by setting the T ratio to 16000 ppm or less, the occurrence of base thermal cracks can be suppressed to 20% or less. For example, Figure 7 In the example shown, a 20% grid is shown, but the 20% line and the approximate line AL1 intersect at a T ratio of about 16000 ppm. Here, the approximate line AL1 is a straight line set based on the plot of the experimental results using a known approximation method (here, the least squares method), and therefore contains errors. In addition, depending on the approximation method, the position of the approximate line AL1 may sometimes change slightly. Therefore, the range of ±4% from the intersection of the line of the evaluation value set relative to the vertical axis (here, the 20% line) and the approximate line AL1 can actually be regarded as a range existing on the evaluation value line in the evaluation considering the error. In addition, the same explanation applies to the subsequent numerical ranges regarding the method of considering the error with respect to this intersection, so the explanation is omitted. Therefore, it was confirmed that the occurrence of base thermal cracks was suppressed to less than 20% by setting the T ratio to less than 16000 ppm.

[0056] In the multilayer capacitor C1, it is more preferable to suppress the occurrence of base thermal cracks to 10% or less. In this regard, by setting the T ratio to 15000 ppm or less, the occurrence of base thermal cracks can be suppressed to 10% or less. For example, Figure 7 In the example shown, it was confirmed that the occurrence of base thermal cracks can be suppressed to 10% or less by setting the T ratio to 15000 ppm or less, taking into account the 10% position of the approximate line AL1 and the error in the approximate line.

[0057] In the multilayer capacitor C1, it is more preferable to suppress the occurrence of base thermal cracks to 0%. In this regard, by setting the T ratio to 14000 ppm or less, the occurrence of base thermal cracks can be suppressed to 0%. For example, Figure 7 In the example shown, it was confirmed that the occurrence of base thermal cracks can be suppressed to 0% by setting the T ratio to 14000 ppm or less, taking into account the 0% position of the approximate line AL1 and the error in the approximate line.

[0058] In the multilayer capacitor C1, it is preferable to suppress the variation of electrostatic capacitance to CV0.02 or less. In this regard, by setting the T ratio to 11000 ppm or more, the variation of electrostatic capacitance can be suppressed to CV0.02 or less. For example, Figure 7 In the example shown, it was confirmed that the variation in electrostatic capacitance can be suppressed to CV0.02 or less by setting the T ratio to 11000 ppm or more, taking into account the position of CV0.02 of the approximate line AL2 and the error in the approximate line.

[0059] In the multilayer capacitor C1, it is preferable to suppress the variation of electrostatic capacitance to CV0.015 or less. In this regard, by setting the T ratio to 12000 ppm or more, the variation of electrostatic capacitance can be suppressed to CV0.015 or less. Figure 7 In the example shown, it was confirmed that the variation in electrostatic capacitance can be suppressed to CV0.015 or less by setting the T ratio to 12000 ppm or more, taking into account the position of CV0.015 of the approximate line AL2 and the error in the approximate line.

[0060] In the multilayer capacitor C1, it is preferable to suppress the variation of electrostatic capacitance to CV0.01 or less. In this regard, by setting the T ratio to 12500 ppm or more, the variation of electrostatic capacitance can be suppressed to CV0.01 or less. Figure 7 In the example shown, it was confirmed that by setting the T ratio to 12500 ppm or more, the variation in electrostatic capacitance can be suppressed to CV0.01 or less by taking into account the position of CV0.01 of the approximate line AL2 and the error in the approximate line.

[0061] Specifically, the TGap ratio is preferably 96000 ppm to 176000 ppm. In addition, the TGap ratio is more preferably 165000 ppm or less, and further preferably 154000 ppm or less. In addition, the TGap ratio is more preferably 121000 ppm or more, and further preferably 137000 ppm or more.

[0062] In the multilayer capacitor C1, it is preferred to suppress the occurrence of base thermal cracks to 20% or less. In this regard, by setting the TGap ratio to 176000 ppm or less, the occurrence of base thermal cracks can be suppressed to 20% or less. For example, Figure 8 In the example shown, it was confirmed that the occurrence of base thermal cracks can be suppressed to 20% or less by setting the TGap ratio to 176000 ppm or less, taking into account the 20% position of the approximate line AL3 and the error in the approximate line.

[0063] In the multilayer capacitor C1, it is more preferable to suppress the occurrence of base thermal cracks to 10% or less. In this regard, by setting the TGap ratio to 165000 ppm or less, the occurrence of base thermal cracks can be suppressed to 10% or less. For example, Figure 8 In the example shown, it was confirmed that the occurrence of base thermal cracks can be suppressed to 10% or less by setting the TGap ratio to 165000 ppm or less, taking into account the 10% position of the approximate line AL3 and the error in the approximate line.

[0064] In the multilayer capacitor C1, it is more preferable to suppress the occurrence of base thermal cracks to 0%. In this regard, by setting the TGap ratio to 154000 ppm or less, the occurrence of base thermal cracks can be suppressed to 0%. For example, Figure 8 In the example shown, it was confirmed that the occurrence of base thermal cracks can be suppressed to 0% by setting the TGap ratio to 154000 ppm or less, taking into account the 0% position of the approximate line AL3 and the error in the approximate line.

[0065] In the multilayer capacitor C1, it is preferable to suppress the variation of electrostatic capacitance to CV0.035 or less. In this regard, by setting the TGap ratio to 96000 ppm or more, the variation of electrostatic capacitance can be suppressed to CV0.035 or less. Figure 8 In the example shown, it was confirmed that by setting the TGap ratio to 96000 ppm or more, the variation in electrostatic capacitance can be suppressed to CV0.035 or less, taking into account the position of CV0.035 of the approximate line AL4 and the error in the approximate line.

[0066] In the multilayer capacitor C1, it is preferred to suppress the variation of electrostatic capacitance to CV0.02 or less. In this regard, by setting the TGap ratio to 121000 ppm or more, the variation of electrostatic capacitance can be suppressed to CV0.02 or less. For example, Figure 8 In the example shown, it was confirmed that the variation in electrostatic capacitance can be suppressed to CV0.02 or less by setting the TGap ratio to 121000 ppm or more, taking into account the position of CV0.02 of the approximate line AL4 and the error in the approximate line described above.

[0067] In the multilayer capacitor C1, it is preferable to suppress the variation of electrostatic capacitance to CV0.01 or less. In this regard, by setting the T ratio to 137000 ppm or more, the variation of electrostatic capacitance can be suppressed to CV0.01 or less. For example, Figure 8In the example shown, it was confirmed that the variation in electrostatic capacitance can be suppressed to CV0.01 or less by setting the TGap ratio to 137000 ppm or more in consideration of the position of CV0.01 of the approximate line AL4 and the error in the approximate line.

[0068] Next, the operation and effects of the multilayer capacitor C1 according to the present embodiment will be described.

[0069] If the protrusion β is too large, the possibility of cracks caused by the difference in thermal shrinkage between the inner layer 20 and the outer layer 22 increases. On the other hand, if the protrusion β is too small, the deviation of the electrostatic capacitance may be affected by the poor contact between the internal electrodes 11, 13 and the external electrodes 5, 7 due to thinning and multi-layering. In contrast, the inventors of the present invention conducted in-depth research and found that there is a correlation between the T ratio of the protrusion β to the dimension T in the second direction D2 of the element body 2 and the performance of the stacked capacitor C1, and found an appropriate range. Specifically, by setting the T ratio of the protrusion β to the dimension T in the second direction D2 of the element body 2 to less than 16000 ppm, cracks can be suppressed. In addition, by setting the T ratio of the protrusion β to the dimension T in the second direction D2 of the element body 2 to more than 11000 ppm, the deviation of the electrostatic capacitance can be suppressed. As described above, the performance of the stacked capacitor C1 can be improved.

[0070] The T ratio may be 15000 ppm or less, or 14000 ppm or less. In this case, cracking can be further suppressed.

[0071] The T ratio may be 12000 ppm or more, or 12500 ppm or more. In this case, the variation in electrostatic capacitance can be further reduced.

[0072] In addition, the inventors of the present invention conducted in-depth research and found that there is a correlation between the TGap ratio of the protrusion amount β relative to the dimension TGap in the second direction D2 of the outer layer 22 on one side and the performance of the stacked capacitor C1, and found an appropriate range. Specifically, by setting the TGap ratio of the protrusion amount β to the dimension TGap in the second direction D2 of the outer layer 22 on one side to 176000 ppm or less, cracks can be suppressed. In addition, by setting the ratio of the protrusion amount β to the dimension TGap in the second direction D2 of the outer layer 22 on one side to 96000 ppm or more, the deviation of the electrostatic capacitance can be suppressed. As described above, the performance of the stacked capacitor C1 can be improved.

[0073] The TGap ratio may be 165000 ppm or less, or 154000 ppm or less. In this case, cracking can be further suppressed.

[0074] The TGap ratio may be 121000 ppm or more, or 137000 ppm or more. In this case, the variation in electrostatic capacitance can be further reduced.

[0075] The internal electrodes 11 and 13 have main electrode portions 11a and 13a that form electrostatic capacitance and connecting portions 11b and 13b that connect the main electrode portions 11a and 13a to the external electrodes 5 and 7. In the third direction D3 relative to a pair of side surfaces 2e and 2f, the width dimension of the connecting portions 11b and 13b may be smaller than the width dimension of the main electrode portions 11a and 13a. In this case, the infiltration of the plating solution near the connecting portions 11b and 13b can be suppressed, but on the other hand, cracks or deviations in electrostatic capacitance are likely to occur. In contrast, by setting the T ratio and the TGap ratio to the above range, the infiltration of the plating solution can be suppressed and the deviations in cracks and electrostatic capacitance can be suppressed.

[0076] The present invention is not limited to the above-mentioned embodiments.

[0077] In the above-mentioned embodiment, the size TGap of the pair of outer layer portions 22 is described as being the same size. However, the size TGap may be different between the upper outer layer portion 22 and the lower outer layer portion 22. In this case, the range of the TGap ratio relative to the size TGap of at least one outer layer portion 22 is sufficient as long as it is included in the above-mentioned range. In addition, a pair of external electrodes 5 and 7 are provided, but the range of the T ratio and the TGap ratio relative to at least one external electrode 5 and 7 is sufficient as long as it is included in the above-mentioned range.

[0078] In addition, in the present invention, as long as at least the range of the TGap ratio is included in the above range, the range of the T ratio does not necessarily need to be included in the above range.

[0079] [evaluate]

[0080] Under the above experimental conditions, Figure 6 The experimental results shown are evaluated. Here, component A, component C-6, and component C-7 are cited as comparative examples, and component B and components C-1 to C-5 are cited as examples. The thermal cracks of component B and components C-1 to C-5 of the example are suppressed to less than 20%, and the deviation of electrostatic capacitance (neglecting two decimal places) is suppressed to less than CV0.035%.

Claims

1. A stacked capacitor, wherein: have: A body having a pair of end faces opposite to each other, a pair of side faces and a pair of main faces located between the pair of end faces and extending in a first direction opposite to the pair of end faces; and a pair of external electrodes disposed on the pair of end surfaces, The element body has: An inner layer portion formed by laminating a plurality of inner electrodes and a plurality of dielectric layers in a second direction in which the pair of main surfaces are opposed to each other; and a pair of outer layer portions, which are arranged on the outer side of the inner layer portion in the second direction, On at least one of the pair of end surfaces, the internal electrode of one of the inner layer portions protrudes outwardly in the first direction relative to the outer layer portion by a predetermined amount, The ratio of the protrusion amount to the dimension of the outer layer portion in the second direction is 122867 ppm to 155533 ppm, The protrusion amount is 18 to 23 μm, The dimension of the outer layer portion in the second direction is 90 to 200 μm. The dimension of the element body in the first direction is 1450 μm to 3600 μm, The dimension of the element body in the second direction is 600 μm to 2900 μm, A ratio of the protrusion amount to a dimension of one of the outer layer portions in the first direction is 5864 ppm to 7446 ppm.

2. The multilayer capacitor according to claim 1, wherein: A ratio of the protrusion amount to a dimension of one of the outer layer portions in the second direction is 154000 ppm or less.

3. The multilayer capacitor according to claim 1 or 2, wherein: A ratio of the protrusion amount to a dimension of one of the outer layer portions in the second direction is 137000 ppm or more.

4. The multilayer capacitor according to any one of claims 1 to 3, wherein The internal electrode includes a main electrode portion forming an electrostatic capacitor and a connection portion connecting the main electrode portion and the external electrode. In a third direction in which the pair of side surfaces are opposed to each other, a width dimension of the connection portion is smaller than a width dimension of the main electrode portion.

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