Ceramic multilayer substrate and RFID tag

Abstract

This ceramic multilayer substrate includes a laminate having a plurality of first ceramic layers and a plurality of second ceramic layers, wherein when the thickness of the laminate is Z, and the laminate is divided into a first layer and a second layer, each having a thickness of Z / 2, the ceramic multilayer substrate includes a first electrode disposed on the main surface on the first layer side of the laminate, and a second electrode disposed on the main surface on the second layer side of the laminate. The sintering temperature of the second ceramic layers is higher than the sintering temperature of the first ceramic layers. When the total area of the first electrode is S1, the total volume of the second ceramic layers included in the first layer is K1, the total area of the second electrode is S2, and the total volume of the second ceramic layers included in the second layer is K2, S1 > S2 and K1 > K2.

Description

Ceramic multilayer substrate and RFID tag

[0001] The present invention relates to a ceramic multilayer substrate and an RFID (Radio-Frequency Identification) tag including the same.

[0002] Conventionally, there are ceramic multilayer substrates used in RFID tags. In Patent Document 1, a coil electrode is disposed inside the multilayer substrate, and an electrode connected to the coil electrode is disposed on the top surface of the multilayer substrate, and an RFIC (Radio-Frequency Integrated Circuit) is mounted on this electrode.

[0003] JP 2012-59015 A

[0004] However, when manufacturing a ceramic multilayer substrate, the ceramic multilayer substrate may warp into a convex or concave shape during firing due to the imbalance in electrode arrangement.

[0005] An object of the present invention is to provide a ceramic multilayer substrate and an RFID tag that reduce warpage of the substrate.

[0006] A ceramic multilayer substrate according to one embodiment of the present invention comprises a laminate having a plurality of first ceramic layers and a plurality of second ceramic layers. When the thickness of the laminate is Z and the laminate is divided into a first layer and a second layer at a thickness of Z / 2, the ceramic multilayer substrate comprises a first electrode disposed on a main surface of the laminate facing the first layer, and a second electrode disposed on a main surface of the laminate facing the second layer. The sintering temperature of the second ceramic layer is higher than the sintering temperature of the first ceramic layer. When the total area of ​​the first electrodes is S1, the total volume of the second ceramic layers included in the first layer is K1, the total area of ​​the second electrodes is S2, and the total volume of the second ceramic layers included in the second layer is K2, S1 > S2 and K1 > K2.

[0007] A ceramic multilayer substrate according to one embodiment of the present invention includes a laminate having a plurality of first ceramic layers and a plurality of second ceramic layers. The ceramic multilayer substrate includes a coil electrode laminated on at least one of the first and second ceramic layers within the laminate. The sintering temperature of the second ceramic layer is higher than the sintering temperature of the first ceramic layer. When the thickness of the laminate is Z and the laminate is divided into a first layer and a second layer at a thickness of Z / 2, the total area A1 of the coil electrodes included in the first layer, the total volume K1 of the second ceramic layers included in the first layer, the total area A2 of the coil electrodes included in the second layer, and the total volume K2 of the second ceramic layers included in the second layer satisfy the relationships A1 > A2 and K1 > K2.

[0008] An RFID tag according to one aspect of the present invention includes any one of the ceramic multilayer substrates described above and an RFIC mounted on the ceramic multilayer substrate.

[0009] According to the present invention, it is possible to provide a ceramic multilayer substrate and an RFID tag in which warpage of the substrate is reduced.

[0010] 1 is a longitudinal sectional view showing an outline of a ceramic multilayer substrate according to a first embodiment; 2 is an exploded perspective view showing a laminated structure of a ceramic multilayer substrate; 3 is an explanatory diagram showing one step in manufacturing a ceramic multilayer substrate according to a comparative example; 4 is an explanatory diagram showing one step in manufacturing a ceramic multilayer substrate according to a comparative example; 5 is an explanatory diagram showing one step in manufacturing a ceramic multilayer substrate according to a comparative example; 6 is an explanatory diagram showing one step in manufacturing a ceramic multilayer substrate according to a comparative example;

[0011] Each of the embodiments described below shows a specific example of the present invention, and the present invention is not limited to this configuration. Furthermore, the numerical values, shapes, configurations, steps, and step orders specifically shown in the following embodiments are examples and do not limit the present invention. Among the components in the following embodiments, components that are not described in the independent claims that represent the highest concepts are described as optional components. Furthermore, in all embodiments, the configurations in each modification are the same, and the configurations described in each modification may be combined with each other.

[0012] 1 and 2, a schematic configuration of a ceramic multilayer substrate 1 according to a first embodiment of the present invention will be described. Fig. 1 is a longitudinal cross-sectional view of the ceramic multilayer substrate 1 according to the first embodiment. Note that the direction along the top surface 13, which corresponds to the first main surface of the ceramic multilayer substrate 1, is defined as the horizontal direction, and the direction perpendicular to the top surface 13 is defined as the vertical direction.

[0013] In the first embodiment, the ceramic multilayer substrate 1 includes a laminate 5 having a plurality of first ceramic layers 3 and a plurality of second ceramic layers 4. The ceramic multilayer substrate 1 further includes a coil electrode 6 laminated on the second ceramic layers 4 within the laminate 5.

[0014] In the first embodiment, the laminate 5 includes, for example, six first ceramic layers 3, and the first ceramic layers 31, 32, 33, 34, 35, and 36 are arranged from the bottom to the top of the laminate 5. The first ceramic layers 31, 32, 33, 34, 35, and 36 are collectively referred to simply as the first ceramic layers 3. The number of first ceramic layers 3 included in the laminate 5 is not limited to six, and may be two or more.

[0015] The first ceramic layer 3 is formed by firing a ceramic green sheet made of, for example, low temperature co-fired ceramics (LTCC).

[0016] In the first embodiment, the laminate 5 includes, for example, seven second ceramic layers 4, and the second ceramic layers 41, 42, 43, 44, 45, 46, and 47 are arranged from the bottom to the top of the laminate 5. The second ceramic layers 41, 42, 43, 44, 45, 46, and 47 are collectively referred to simply as the second ceramic layers 4. The number of second ceramic layers 4 included in the laminate 5 is not limited to seven, and may be two or more.

[0017] The second ceramic layer 4 has a higher sintering temperature than the first ceramic layer 3 and is made of a ceramic material containing, for example, alumina or zirconia as its main component.

[0018] A coil electrode 6 is disposed on the second ceramic layer 4. The coil electrode 6 is wound in a coil shape by connecting conductor patterns 61, 62, 63, 64, and 65 disposed on each second ceramic layer 4 with interlayer connection conductors 7. The interlayer connection conductor 7 is a collective term for the interlayer connection conductors 71 to 76 that connect the conductor patterns 61 to 65.

[0019] In the laminate 5, the layers are stacked in the following order from bottom to top: second ceramic layer 41, conductor pattern 61, first ceramic layer 31, second ceramic layer 42, conductor pattern 62, first ceramic layer 32, second ceramic layer 43, conductor pattern 63, first ceramic layer 33, second ceramic layer 44, conductor pattern 64, first ceramic layer 34, second ceramic layer 45, conductor pattern 65, first ceramic layer 35, second ceramic layer 46, first ceramic layer 36, and second ceramic layer 47.

[0020] First electrodes 81 and 82 are disposed on the upper surface of the laminate 5. Therefore, the first electrodes 81 and 82 are disposed on the second ceramic layer 47. In the first embodiment, two first electrodes are disposed, but one, or three or more may be disposed. The first electrodes 81 and 82 are, for example, electrodes for mounting an IC. The first electrodes 81 and 82 are collectively referred to as the first electrodes 8. The first electrodes 81 and 82 are, for example, squares measuring 0.5 mm on each side.

[0021] The first electrode 81 and one end of the conductor pattern 65 are connected by an interlayer connection conductor 71, and the other end of the conductor pattern 65 and one end of the conductor pattern 64 are connected by an interlayer connection conductor 72. The other end of the conductor pattern 64 and one end of the conductor pattern 63 are connected by an interlayer connection conductor 73, and the other end of the conductor pattern 63 and one end of the conductor pattern 62 are connected by an interlayer connection conductor 74. The other end of the conductor pattern 62 and one end of the conductor pattern 61 are connected by an interlayer connection conductor 75, and the other end of the conductor pattern 61 and the first electrode 82 are connected by an interlayer connection conductor 76. In this way, the first electrodes 81 and 82 are connected to the coil electrode 6.

[0022] A second electrode 9 is disposed on the lower surface of the laminate 5. In the first embodiment, one second electrode is disposed, but two or more second electrodes may be disposed.

[0023] The thickness Z of the laminate 5 is, for example, 0.60 mm. The line width of each of the conductor patterns 61 to 65 of the coil electrode 6 is, for example, 0.15 mm, and the thickness of each of the conductor patterns 61 to 65 of the coil electrode 6 is, for example, 0.03 mm. The pitches of the conductor patterns 61 to 65 do not match in the direction from the top surface 13, which is one main surface of the laminate 5, to the bottom surface 14, which is the other main surface.

[0024] The ceramic multilayer substrate 1 is formed by producing a single large ceramic multilayer substrate 100 as shown in Fig. 3 and dicing it into individual pieces. The individual ceramic multilayer substrates 1 have, for example, a square shape with each side measuring 2.0 mm. The ceramic multilayer substrate 100 has, for example, a rectangular shape, for example, a square shape with each side measuring 10 cm.

[0025] Next, the effect of the second ceramic layer 4 will be described. Figures 4 to 6 are explanatory views showing a step in the manufacture of a ceramic multilayer substrate 100A according to a comparative example. The ceramic multilayer substrate 100A according to the comparative example does not include the second ceramic layer 4. Note that the coil electrodes in the laminate 5A are omitted from the illustration in Figures 4 to 6.

[0026] 4, each of the first ceramic layers 31A and 32A is formed by laminating the above-described sheet-like ceramic green sheets in order. A first electrode 8A is formed on the upper surface of the first ceramic layer 32A.

[0027] Next, the laminate 5A on which the first electrode 8A has been formed is fired, and when the firing temperature exceeds 700°C, the first electrode 8A begins to shrink in two directions, that is, in the thickness direction and in the direction along the top surface of the first ceramic layer 32A, as shown in Fig. 5. When the firing temperature reaches 1000°C, the first ceramic layers 31A and 32A are also sintered and shrink.

[0028] As the firing temperature rises from 700° C. to 1000° C., the first ceramic layers 31A, 32A soften. As a result, the first ceramic layers 31A, 32A are pulled in turn by the horizontal contraction force of the first electrode 8A, causing the entire ceramic multilayer substrate 100 to warp concavely, as shown in FIG.

[0029] Next, reference is made to Figures 7 to 9. Figures 7 to 9 are explanatory views showing a step in the manufacture of a ceramic multilayer substrate 100B having a second ceramic layer 41B. Note that in Figures 7 to 9, the coil electrodes in the laminate 5B are omitted.

[0030] 7, the second ceramic layer 41B is formed by printing on the first ceramic layer 31B, which is the above-described sheet-like ceramic green sheet. The first electrode 8A is further formed on the upper surface of the second ceramic layer 41B.

[0031] The sintering temperature of the second ceramic layer 41B is 1300 to 1500° C. When the second ceramic layer 41B is fired at about 1000° C., the sintering of the second ceramic layer 41B does not progress and there is no shrinkage. Therefore, as shown in FIG. 8 , even if the firing temperature exceeds 700° C. and the first electrode 8B begins to shrink, the second ceramic layer 41B does not soften, so that the first electrode 8B can be prevented from shrinking in the horizontal direction and can shrink only in the thickness direction.

[0032] 9, even when the firing temperature reaches 1000°C and the first ceramic layer 31B begins to shrink, the second ceramic layer 41B does not soften, so that the first ceramic layer 31B is prevented from shrinking in the horizontal direction and is allowed to shrink only in the thickness direction. In this way, by including the second ceramic layer 41B in the laminate 5B, it is possible to prevent the ceramic multilayer substrate 100B from warping due to the shrinkage force of the first electrode 8B.

[0033] 1, the total area of ​​the first electrodes 8 arranged on the upper surface 13 of the laminate 5 is larger than the total area of ​​the second electrodes 9 arranged on the lower surface 14 of the laminate 5, and therefore the horizontal tensile force generated during firing is greater on the upper surface 13 than on the lower surface 14 of the laminate 5. In this way, the horizontal tensile force generated in the laminate 5 differs between the upper surface 13 and the lower surface 14, making the laminate 5 more likely to warp.

[0034] Therefore, the laminate 5 of embodiment 1 suppresses warping of the laminate 5 by increasing the density of the second ceramic layer 4 within the laminate 5 on the side with the larger electrode area arranged on the upper surface 13 and lower surface 14 of the laminate 5, respectively.

[0035] Similarly, depending on whether the total area of ​​the conductor patterns 61 to 65 of the coil electrode 6 located on the upper surface 13 side inside the laminate 5 is larger or the total area of ​​the conductor patterns 61 to 65 located on the lower surface 14 side inside the laminate 5 is larger, a bias will occur in the horizontal tensile force generated during firing, making the laminate 5 more likely to warp.

[0036] Therefore, the laminate 5 of embodiment 1 suppresses warping of the laminate 5 by increasing the density of the second ceramic layer 4 within the laminate 5 on the side of the laminate 5 where the total area of ​​the conductor patterns 61 to 65 arranged inside the laminate 5 is larger in the vertical direction.

[0037] When the laminate 5 is divided into a first layer Ly1 and a second layer Ly2 at half the thickness (Z / 2) of the laminate 5, where A1 is the total area of ​​the conductor patterns 63, 64, and 65 of the coil electrode 6 included in the first layer Ly1, K1 is the total volume of the second ceramic layers 44, 45, 46, and 47, and A2 is the total area of ​​the conductor patterns 61 and 62 of the coil electrode 6 included in the second layer Ly2, and K2 is the total volume of the second ceramic layers 41, 42, and 43, A1 > A2 and K1 > K2.

[0038] With this configuration, more of the second ceramic layers 4 are arranged on the side of the laminate 5 where there are more conductor patterns of the coil electrodes 6 in the vertical direction, thereby preventing warping of the ceramic multilayer substrate 1.

[0039] As described above, the ceramic multilayer substrate 1 of the first embodiment is a ceramic multilayer substrate 1 including a laminate 5 having a plurality of first ceramic layers 3 and a plurality of second ceramic layers 4. When the thickness of the laminate 5 is Z and the laminate 5 is divided into a first layer Ly1 and a second layer Ly2 by a thickness of Z / 2, the ceramic multilayer substrate 1 includes a first electrode 8 disposed on an upper surface 13 of the laminate 5 on the first layer Ly1 side and a second electrode 9 disposed on a lower surface 14 of the laminate 5 on the second layer Ly2 side. The sintering temperature of the second ceramic layers 4 is higher than the sintering temperature of the first ceramic layers 3. When the total area of ​​the first electrodes 8 is S1, the total volume K1 of the second ceramic layers 4 included in the first layer Ly1 is S2, the total area of ​​the second electrodes 9 is S2, and the total volume K2 of the second ceramic layers 4 included in the second layer Ly2 are S1 > S2 and K1 > K2.

[0040] With the ceramic multilayer substrate 1 having this configuration, when the laminate 5 is divided into a first layer Ly1 and a second layer Ly2, each half the thickness in the thickness direction, the first layer Ly1, which has a larger total area of ​​the electrodes arranged on the first layer Ly1 and the second layer Ly2, respectively, has a larger total volume of the second ceramic layer 4 than the second layer Ly2, thereby preventing warping of the laminate 5 when it is fired.

[0041] In addition, in FIG. 1, when the total electrode volume of the first electrode 8 is M1 and the total electrode volume of the second electrode 9 is M2, M1>M2.

[0042] Since the total volume of the second ceramic layer 4 of the first layer Ly1 on the first electrode 8 side, which has a larger total electrode volume than the second electrode 9, is larger than that of the second layer Ly2, warping can be prevented from occurring when the laminate 5 is fired.

[0043] The ceramic multilayer substrate 1 of the first embodiment is a ceramic multilayer substrate 1 including a laminate 5 having a plurality of first ceramic layers 3 and a plurality of second ceramic layers 4. The ceramic multilayer substrate 1 includes a coil electrode 6 laminated on the second ceramic layer 4 inside the laminate 5. The sintering temperature of the second ceramic layer 4 is higher than the sintering temperature of the first ceramic layer 3. When the thickness of the laminate 5 is Z and the laminate 5 is divided into a first layer Ly1 and a second layer Ly2 by a thickness of Z / 2, the total area A1 of the coil electrodes 6 included in the first layer Ly1, the total volume K1 of the second ceramic layers 4 included in the first layer Ly1, the total area A2 of the coil electrodes 6 included in the second layer Ly2, and the total volume K2 of the second ceramic layers 4 included in the second layer Ly2 satisfy A1 > A2 and K1 > K2.

[0044] According to the ceramic multilayer substrate 1 having this configuration, when the laminate 5 is divided into a first layer Ly1 and a second layer Ly2, each of which is half the thickness in the thickness direction, the first layer Ly1, which has the larger total area of ​​the coil electrodes 6, has a larger total volume of the second ceramic layer 4 than the second layer Ly2, and therefore, warping of the laminate 5 can be suppressed when it is fired.

[0045] The thicknesses of the conductor patterns 61 to 65 of the coil electrode 6 are substantially the same. Therefore, in the ceramic multilayer substrate 1, when the total electrode volume of the coil electrodes 6 included in the first layer Ly1 is V1 and the total electrode volume of the coil electrodes 6 included in the second layer Ly2 is V2, V1 > V2.

[0046] Between the first layer Ly1 and the second layer Ly2, the first layer Ly1, which has a larger total electrode volume of the coil electrode 6, has a larger total volume of the second ceramic layer 4, so warping can be prevented from occurring when the laminate 5 is fired.

[0047] Furthermore, the number of laminated second ceramic layers 4 in the first layer Ly1 is greater than the number of laminated second ceramic layers 4 in the second layer Ly2. As a result, the number of laminated second ceramic layers 4 in the first layer Ly1 having a larger total surface area of ​​the surface electrodes or a larger total area of ​​the coil electrodes 6 is greater than the second layer Ly2, which makes it possible to suppress warping of the laminate 5 when it is fired.

[0048] Furthermore, the total thickness of the second ceramic layers 4 in the first layer Ly1 is greater than the total thickness of the second ceramic layers 4 in the second layer Ly2. As a result, the total thickness of the second ceramic layers 4 in the first layer Ly1 having a larger total area of ​​the surface electrodes or a larger total area of ​​the coil electrodes 6 is greater than that of the second layer Ly2, which makes it possible to suppress warping when firing the laminate 5.

[0049] 10, an RFID tag 21 may be configured by attaching an RFIC 10 to first electrodes 81 and 82 of a ceramic multilayer substrate 1. In this case, the coil electrode 6 functions as a coil antenna, and the RFIC 10 can perform wireless communication.

[0050] Next, a ceramic multilayer substrate 1D according to Modification 1 of Embodiment 1 will be described with reference to Fig. 11. The conductor patterns 61 to 65 of the coil electrode 6 of the ceramic multilayer substrate 1 described above are arranged at uneven pitches in the vertical direction, but the conductor patterns 61 to 63, 65 of the coil electrode 6 of the ceramic multilayer substrate 1D according to Embodiment 2 are arranged at equal pitches.

[0051] As shown in FIG. 11, the conductor patterns 61 to 63 and 65 of the coil electrode 6 are arranged at equal pitches, so that when the coil electrode 6 is used as an antenna, good communication characteristics can be obtained.

[0052] Second Embodiment Next, a ceramic multilayer substrate 1E according to a second embodiment will be described with reference to Fig. 12. Fig. 12 is a longitudinal sectional view showing an outline of the ceramic multilayer substrate 1E according to the second embodiment.

[0053] The thickness of the second ceramic layer 4 in the ceramic multilayer substrate 1 of embodiment 1 was constant, but in the ceramic multilayer substrate 1E of embodiment 2, the thickness of each of the first ceramic layer 3 and the second ceramic layer 4 is made constant by changing the thickness of each of the first ceramic layer 3 and the second ceramic layer 4 according to the distance from the main surfaces (upper surface 13, lower surface 14) of the laminate 5E.

[0054] 12 , the sum of the thicknesses of a pair of the first ceramic layer 3 and the second ceramic layer 4 is constant. For example, the sum of the thicknesses of the second ceramic layer 46 and the first ceramic layer 35, the sum of the thicknesses of the second ceramic layer 45 and the first ceramic layer 34, the sum of the thicknesses of the second ceramic layer 44 and the first ceramic layer 33, the sum of the thicknesses of the second ceramic layer 43 and the first ceramic layer 32, and the sum of the thicknesses of the second ceramic layer 42 and the first ceramic layer 31 are all the same.

[0055] Since the total area S1 of the first electrodes 8 arranged on the upper surface 13 of the laminate 5E is larger than the total area S2 of the second electrodes 9 arranged on the lower surface 14, the thickness of the second ceramic layer 4 increases and the thickness of the first ceramic layer 3 decreases as one approaches the first electrode 8 from the second electrode 9 in the vertical direction.

[0056] According to the ceramic multilayer substrate 1E of embodiment 2, by making the second ceramic layer 4 on the side of the laminate 5E with the larger surface electrode area thicker, the density of the second ceramic layer 4 on the side of the laminate 5E with the larger surface electrode area can be increased, and warping of the ceramic multilayer substrate 1 can be suppressed.

[0057] Third Embodiment Next, a ceramic multilayer substrate 1F according to a third embodiment will be described with reference to Fig. 13. Fig. 13 is a longitudinal sectional view showing an outline of a ceramic multilayer substrate 1F according to the third embodiment.

[0058] In the ceramic multilayer substrate 1F of the third embodiment, the first ceramic layers 3 have the same thickness, and the second ceramic layers 4 have the same thickness. Since the total area S1 of the first electrodes 8 arranged on the upper surface 13 of the laminate 5F is larger than the total area S2 of the second electrodes 9 arranged on the lower surface 14, a recess 16 is formed in the lower part of the laminate 5F to adjust the amount of the second ceramic layer in the laminate 5F.

[0059] The second electrode 9 may be disposed inside the recess 16 or may be disposed on the surface of the laminate 5F outside the recess 16.

[0060] According to the ceramic multilayer substrate 1F of embodiment 3, by forming a recess 16 on the side of the laminate 5F with a smaller surface electrode area, the relative density of the second ceramic layer 4 on the side of the laminate 5F with a larger surface electrode area can be increased, and warping of the ceramic multilayer substrate 1 can be suppressed.

[0061] Although the present invention has been described in various embodiments with a certain degree of detail, the disclosure of these embodiments may vary in structural details, and variations in the combination and order of elements in the various embodiments may be realized without departing from the scope and spirit of the invention as claimed.

[0062] A ceramic multilayer substrate according to a first aspect of the present invention includes a laminate having a plurality of first ceramic layers and a plurality of second ceramic layers. When the thickness of the laminate is Z and the laminate is divided into a first layer and a second layer at a thickness of Z / 2, the ceramic multilayer substrate includes a first electrode disposed on a main surface of the laminate facing the first layer, and a second electrode disposed on a main surface of the laminate facing the second layer. The sintering temperature of the second ceramic layers is higher than the sintering temperature of the first ceramic layers. S1 represents the total area of ​​the first electrodes, K1 represents the total volume of the second ceramic layers included in the first layer, S2 represents the total area of ​​the second electrodes, and K2 represents the total volume of the second ceramic layers included in the second layer, where S1 > S2 and K1 > K2.

[0063] According to this aspect of the ceramic multilayer substrate, when the laminate is divided into a first layer and a second layer, each half the thickness in the thickness direction, the first layer, which has a larger total area of ​​the electrodes arranged on the first layer and the second layer, has a larger total volume of the second ceramic layer than the second layer, thereby preventing the laminate from warping when fired.

[0064] A ceramic multilayer substrate according to a second aspect of the present invention includes a laminate having a plurality of first ceramic layers and a plurality of second ceramic layers. The ceramic multilayer substrate includes a coil electrode laminated on at least one of the first and second ceramic layers within the laminate. The sintering temperature of the second ceramic layer is higher than that of the first ceramic layer. When the thickness of the laminate is Z and the laminate is divided into a first layer and a second layer at a thickness of Z / 2, the total area A1 of the coil electrodes included in the first layer, the total volume K1 of the second ceramic layers included in the first layer, the total area A2 of the coil electrodes included in the second layer, and the total volume K2 of the second ceramic layers included in the second layer satisfy the relationships A1 > A2 and K1 > K2.

[0065] According to this embodiment of the ceramic multilayer substrate, when the laminate is divided into a first layer and a second layer, each half the thickness in the thickness direction, the first layer, which has a larger total area of ​​the coil electrodes, has a larger total volume of the second ceramic layer than the second layer, so that warping of the laminate 5 can be suppressed when it is fired.

[0066] According to the third aspect, in the ceramic multilayer substrate of the first aspect, when the total electrode volume of the first electrodes is M1 and the total electrode volume of the second electrodes is M2, M1>M2.

[0067] According to the fourth aspect, in the ceramic multilayer substrate of the second aspect, when the total electrode volume of the coil electrodes included in the first layer is V1 and the total electrode volume of the coil electrodes included in the second layer is V2, V1 > V2.

[0068] According to a fifth aspect, in the ceramic multilayer substrate of any one of the first to fourth aspects, the number of second ceramic layers stacked in the first layer is greater than the number of second ceramic layers stacked in the second layer.

[0069] According to a sixth aspect, in the ceramic multilayer substrate of any one of the first to fifth aspects, the total thickness of the second ceramic layers in the first layer is greater than the total thickness of the second ceramic layers in the second layer.

[0070] According to a seventh aspect, in the ceramic multilayer substrate of the second or fourth aspect, the coil electrode includes a plurality of conductor patterns respectively arranged on a plurality of second ceramic layers, and the pitches of the plurality of conductor patterns are non-uniform in the direction from one main surface of the laminate to the other main surface.

[0071] According to an eighth aspect, the ceramic multilayer substrate of the first or third aspect further comprises a coil electrode laminated on at least one of the first and second ceramic layers inside the laminate.

[0072] According to a ninth aspect, the ceramic multilayer substrate according to any one of the second, fourth, and seventh aspects further comprises a first electrode disposed on a main surface of the laminate on the first layer side.

[0073] According to a tenth aspect, in the ceramic multilayer substrate of the eighth or ninth aspect, the first electrode is an electrode for mounting an IC.

[0074] An RFID tag according to an eleventh aspect includes the ceramic multilayer substrate according to the tenth aspect and an RFIC mounted on the first electrode.

[0075] DESCRIPTION OF SYMBOLS 1 Ceramic multilayer substrate 3 First ceramic layer 4 Second ceramic layer 5, 5A Laminate 6 Coil electrode 7 Interlayer connection conductor 8 First electrode 9 Second electrode 10 RFIC 13 Upper surface 14 Lower surface 16 Recess 21 RFID tag 31, 32, 33, 34, 35, 36 First ceramic layer 41, 42, 43, 44, 45, 46, 47 Second ceramic layer 61, 62, 63, 64, 65 Conductor pattern 71, 72, 73, 74, 75, 76 Interlayer connection conductor 81, 82 First electrode 100 Ceramic multilayer substrate Ly1 First layer Ly2 Second layer

Claims

1. A ceramic multilayer substrate comprising a laminate having a plurality of first ceramic layers and a plurality of second ceramic layers, wherein when the thickness of the laminate is Z and the laminate is divided into a first layer and a second layer at a thickness of Z / 2, the substrate comprises: a first electrode disposed on a main surface of the laminate facing the first layer; and a second electrode disposed on a main surface of the laminate facing the second layer; the sintering temperature of the second ceramic layer is higher than the sintering temperature of the first ceramic layer; and when the total area of ​​the first electrodes is S1, the total volume of the second ceramic layers included in the first layer is K1, the total area of ​​the second electrodes is S2, and the total volume of the second ceramic layers included in the second layer is K2, then S1>S2 and K1>K2.

2. A ceramic multilayer substrate comprising a laminate having a plurality of first ceramic layers and a plurality of second ceramic layers, wherein a coil electrode is laminated on at least one of the first or second ceramic layers inside the laminate, and the sintering temperature of the second ceramic layer is higher than that of the first ceramic layer, and when the thickness of the laminate is Z and the laminate is divided into a first layer and a second layer at a thickness of Z / 2, where A1 is the total area of ​​the coil electrodes included in the first layer, K1 is the total volume of the second ceramic layers included in the first layer, A2 is the total area of ​​the coil electrodes included in the second layer, and K2 is the total volume of the second ceramic layers included in the second layer, A1>A2 and K1>K2.

3. The ceramic multilayer substrate according to claim 1, wherein, when the total electrode volume of the first electrodes is M1 and the total electrode volume of the second electrodes is M2, M1 > M2.

4. The ceramic multilayer substrate according to claim 2, wherein V1 is the total electrode volume of the coil electrodes included in the first layer, and V2 is the total electrode volume of the coil electrodes included in the second layer, and V1 > V2.

5. The ceramic multilayer substrate according to any one of claims 1 to 4, wherein the number of second ceramic layers stacked in the first layer is greater than the number of second ceramic layers stacked in the second layer.

6. The ceramic multilayer substrate according to any one of claims 1 to 5, wherein the total thickness of the second ceramic layers in the first layer is greater than the total thickness of the second ceramic layers in the second layer.

7. The ceramic multilayer substrate according to claim 2 or 4, wherein the coil electrode includes a plurality of conductor patterns respectively arranged on the plurality of second ceramic layers, and the pitches of the plurality of conductor patterns are not consistent in the direction from one main surface to the other main surface of the laminate.

8. The ceramic multilayer substrate according to claim 1 or 3, further comprising a coil electrode laminated on at least one of the first and second ceramic layers inside the laminate.

9. The ceramic multilayer substrate according to any one of claims 2, 4 and 7, further comprising a first electrode disposed on a main surface of the laminate on the first layer side.

10. The ceramic multilayer substrate according to claim 8 or 9, wherein the first electrode is an electrode for mounting an IC.

11. An RFID tag comprising the ceramic multilayer substrate according to claim 10 and an RFIC mounted on the first electrode.

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