Electronic component

Abstract

The purpose of the present invention is to provide an electronic component in which a strong bond is formed at a junction interface where a low-temperature fired ceramic having a low dielectric constant and a low-temperature fired ceramic having a high dielectric constant are co-sintered. The electronic component includes a low-dielectric-constant ceramic layer and a high-dielectric-constant ceramic layer. The low-dielectric-constant ceramic layer is formed of a first low-temperature fired ceramic, and the high-dielectric-constant ceramic layer is formed of a second low-temperature fired ceramic. Furthermore, the electronic component includes, at a boundary between the low-dielectric-constant ceramic layer and the high-dielectric-constant ceramic layer, a junction layer containing a crystal of BaAl2Si2O8. Since the electronic component includes the junction layer, a strong bond is formed between the first low-temperature fired ceramic and the second low-temperature fired ceramic, and even when an impact is applied to the electronic component, defects such as delamination and cracks are less likely to occur at the boundary between the low-dielectric-constant ceramic layer and the high-dielectric-constant ceramic layer.

Description

Electronic component

[0001] The present invention relates to an electronic component.

[0002] As a ceramic material for a ceramic multilayer wiring board, a glass-ceramic material (LTCC material) capable of low-temperature firing is known. The LTCC material in the frequency range of the GHz order is used for high-frequency filter applications.

[0003] For miniaturization of electronic components, it is desirable that the capacitive element be formed of a high dielectric constant material layer, and for suppressing dielectric loss, it is desirable that the coil layer be formed of a low dielectric constant material layer. Although several co-sinterings of a high dielectric constant LTCC material and a low dielectric constant LTCC material have been developed (for example, Patent Document 1), in the co-sintering of different materials, peeling occurs at the bonding interface between different materials, and defects such as cracks are likely to occur, and problems such as characteristic variations due to precipitation of different phases also occur.

[0004] International Publication No. 2009 / 113475

[0005] Patent Document 1 discloses, as a low dielectric constant LTCC material, one obtained by adding a glass of Mg ２ SiO ４ as a main component to Li ２ O - RO (R; Ba, Sr, Ca) - MgO - ZnO - B ２ O ３ - SiO ２ and, as a high dielectric constant LTCC material, one obtained by adding the same glass to BaO - TiO ２ - RE ２ O ３ (RE is a rare earth). All of these exhibit good dielectric properties and bond to each other, but the strength of the bonding interface is low, and cracks and delamination occur in impact tests and the like. This is presumably because sufficient mechanical strength cannot be obtained due to reasons such as the bonding interface becoming rough.

[0006] The present invention solves the above problems, and an object thereof is to provide an electronic component in which a strong bond is formed at the bonding interface where a low dielectric constant low-temperature fired ceramic and a high dielectric constant low-temperature fired ceramic are co-sintered.

[0007] The electronic component of the present invention comprises a low-dielectric-constant ceramic layer and a high-dielectric-constant ceramic layer, wherein the low-dielectric-constant ceramic layer is formed from a first low-temperature fired ceramic, and the high-dielectric-constant ceramic layer is formed from a second low-temperature fired ceramic, wherein the first low-temperature fired ceramic comprises a post-fired glass component (A1) and an oxide of the ceramic crystal component (C1), and the second low-temperature fired ceramic comprises a post-fired glass component (A2) and an oxide of the ceramic crystal component (C2), wherein the post-fired glass component (A1) and the post-fired glass component (A2) are BaO-ZnO-Al ２ O ３ -B ２ O ３ -SiO ２ The proportions of BaO, ZnO, and Al contained in the above-mentioned post-fired glass component (A1) and the above-mentioned post-fired glass component (A2) are as follows: ２ O ３ The proportions of each are 0.1 mol% or more and 10 mol% or less, and the proportions of BaO, ZnO and Al contained in the above-mentioned post-fired glass component (A1) and the above-mentioned post-fired glass component (A2), respectively. ２ O ３ The sum of the proportions is 15 mol% or less, and the SiO contained in the above-mentioned post-fired glass component (A1) ２ and B ２ O ３ The ratio of the proportions (SiO ２ / B ２ O ３ ) is less than 3.4, and the oxide (C1) of the above ceramic crystal component is BaAl ２ Si ２ O ８ It includes, and furthermore, SiO ２ , ZnAl ２ O ４ , Zn ２ SiO ４ and TiO ２ The first low-temperature fired ceramic contains BaAl, which is selected from the group consisting of the above. ２ Si ２ O ８ The proportion of is greater than 0% by weight and 5% by weight or less, and the oxide (C2) of the above ceramic crystal component is Ba ２Ti ９ O ２０ , BaTi(BO ３ ) ２ , BaTi ４ O ９ , BaTi ５ O １１ Ba ４ Ti １３ O ３０ BaZn ２ Ti ４ O １１ and Ba ４ ZnTi １１ O ２７ It includes at least one selected from the group consisting of the following, and at the boundary between the low dielectric constant ceramic layer and the high dielectric constant ceramic layer, BaAl ２ Si ２ O ８ The bonding layer comprises a crystal containing the above, and the bonding layer has a thickness of 1 μm or more and less than 10 μm.

[0008] According to the present invention, it is possible to provide an electronic component in which a strong bond is formed at the joint interface where a low dielectric constant low-temperature fired ceramic and a high dielectric constant low-temperature fired ceramic are co-sintered.

[0009] Figure 1 is a schematic cross-sectional view showing an example of a multilayer ceramic electronic component as an electronic component of the present invention. Figure 2 is an enlarged schematic cross-sectional view showing the multilayer ceramic electronic component shown in Figure 1. Figure 3 is a schematic cross-sectional view showing a multilayer green sheet (unfired state) produced during the manufacturing process of the multilayer ceramic electronic component shown in Figure 1.

[0010] The electronic components of the present invention will be described below. However, the present invention is not limited to the configurations described below, and may be modified as appropriate without departing from the spirit of the invention. Furthermore, combinations of several of the preferred configurations described below also constitute the present invention.

[0011] Figure 1 is a schematic cross-sectional view showing an example of a multilayer ceramic electronic component as an electronic component of the present invention. As shown in Figure 1, the electronic component 200 comprises a laminate 100 in which two layers of low-dielectric-constant ceramic layers 4 are laminated, two layers of high-dielectric-constant ceramic layers 5 are laminated, and two more layers of low-dielectric-constant ceramic layers 4 are laminated, and chip components 13 and 14 mounted on the laminate 100. The laminate 100 is also a multilayer ceramic substrate.

[0012] The low dielectric constant ceramic layer 4 is a fired body made of the first low-temperature fired ceramic, and the high dielectric constant ceramic layer 5 is a fired body made of the second low-temperature fired ceramic. Therefore, the laminate 100 formed by stacking the low dielectric constant ceramic layer 4 and the high dielectric constant ceramic layer 5, the multilayer ceramic substrate using the laminate 100, and the electronic component 200 comprising chip components 13 and 14 mounted on the multilayer ceramic substrate (laminated body 100) are all electronic components of the present invention.

[0013] The first low-temperature fired ceramic is a low-dielectric-constant ceramic containing a glass component (A1) and an oxide (C1) of the ceramic crystal component after firing. The first low-temperature fired ceramic included in the electronic component of the present invention is a fired body obtained by firing a low-temperature co-fired ceramic (LTCC) material, which is a glass-ceramic material that can be sintered at a firing temperature of 1000°C or less. In this specification, the relative permittivity of the first low-temperature fired ceramic (low-dielectric-constant ceramic) is 7 or less.

[0014] The glass component after firing (A1) is BaO-ZnO-Al ２ O ３ -B ２ O ３ -SiO ２ Therefore, if the post-fired glass component (A1) contains BaO, the dielectric loss of the first low-temperature fired ceramic can be reduced. The proportion of BaO, the proportion of ZnO, and Al contained in the post-fired glass component (A1) ２ O ３ The proportions of each are 0.1 mol% or more and 10 mol% or less, and the proportions of BaO, ZnO and Al contained in the glass component (A1) after firing are also specified. ２ O ３The sum of the proportions is 15 mol% or less. The first low-temperature fired ceramic used in the present invention has a proportion of BaO, ZnO, and Al contained in the glass component (A1) after firing. ２ O ３ Because the proportion of this element is specified to be small, it is a low-temperature fired ceramic with low dielectric loss.

[0015] Of the components contained in the first low-temperature fired ceramic, the post-fired glass component (A1) has high dielectric loss, while the oxide (C1) of the ceramic crystal component has low dielectric loss. Since the dielectric loss of the post-fired glass component (A1) is dominant in the dielectric loss of the first low-temperature fired ceramic, it is important to reduce the dielectric loss of the post-fired glass component (A1). For this reason, the proportion of BaO, ZnO, and Al contained in the post-fired glass component (A1) is important. ２ O ３ By specifying a small proportion of this, the dielectric loss of the first low-temperature fired ceramic is reduced.

[0016] BaO, ZnO, and Al are contained in the glass components before firing in low-temperature co-fired ceramic (LTCC) materials. ２ O ３ As a result of precipitation outside the glass during firing, the proportion of BaO, ZnO, and Al contained in the glass components after firing is reduced. ２ O ３ The proportion of BaO, ZnO, and Al decreases during firing. ２ O ３ By allowing the material to precipitate outside the glass, low-temperature fired ceramics with low dielectric loss can be obtained.

[0017] The proportion of BaO in the glass component (A1) after firing is preferably 0.3 mol% or more and 7.0 mol% or less, and more preferably 0.4 mol% or more and 6.5 mol% or less.

[0018] The proportion of ZnO in the glass component (A1) after firing is preferably 0.5 mol% or more and 6.0 mol% or less, and more preferably 2.0 mol% or more and 5.5 mol% or less.

[0019] Al contained in the glass component (A1) after firing２ O ３ The proportion of O is preferably 0.5 mol% or more and 9.5 mol% or less, and more preferably 1.0 mol% or more and 9.5 mol% or less.

[0020] The sum of the proportions of BaO, ZnO, and Al ２ O ３ contained in the glass component (A1) after firing is, for example, 1.0 mol% or more, preferably 4.0 mol% or more.

[0021] The glass component (A1) after firing may further contain RO (RO is at least one selected from the group consisting of MgO, CaO, and SrO). When the glass component (A1) after firing contains RO, the proportion of RO contained in the glass component (A1) after firing is 0.1 mol% or more and 10 mol% or less, and the sum of the proportions of BaO, RO, ZnO, and Al ２ O ３ contained in the glass component (A1) after firing is preferably 15 mol% or less.

[0022] Further, it is preferable that the glass component (A1) after firing does not contain an alkali metal oxide. By the glass component (A1) after firing not containing an alkali metal oxide, a low dielectric constant ceramic with a small dielectric loss can be obtained. When the glass component (A1) after firing contains an alkali metal oxide, the proportion of the alkali metal oxide contained in the glass component (A1) after firing is preferably 0.1 mol% or less.

[0023] The preferable proportions of BaO, RO, ZnO, Al ２ O ３ , B ２ O ３ and SiO ２ are as follows. BaO: 0.1 mol% or more and 10 mol% or less RO: 0.1 mol% or more and 10 mol% or less ZnO: 0.1 mol% or more and 10 mol% or less Al ２ O ３ : 0.1 mol% or more and 10 mol% or less B ２ the glass component (A1) after firing is preferably 15 mol% or less. O ３: 20 mol% or more and 45 mol% or less of SiO ２ : 45 mol% or more and 70 mol% or less

[0024] The SiO contained in the fired glass component (A1) ２ and B ２ O ３ The ratio of the proportions (SiO ２ / B ２ O ３ ) is less than 3.4. If the ratio of the proportions of SiO ２ and B ２ O ３ is 3.4 or more, sintering failure occurs and the Q value of the low dielectric constant ceramic becomes low. The ratio of the proportions of SiO ２ and B ２ O ３ is preferably less than 3.3, more preferably less than 3.1. On the other hand, the ratio of the proportions of SiO ２ and B ２ O ３ is preferably 1.4 or more.

[0025] The oxide (C1) of the ceramic crystal component is BaAl ２ Si ２ O ８ contains, and further SiO ２ , ZnAl ２ O ４ and Zn ２ SiO ４ and TiO ２ contains at least two selected from the group consisting of. Since none of these oxides has a high dielectric constant, the dielectric constant of the low dielectric constant ceramic can be adjusted to 7 or less. Also, when the oxide (C1) of the ceramic crystal component has the above composition, when laminating and pressure-bonding a sheet of low dielectric constant low-temperature fired ceramic and a sheet of high dielectric constant low-temperature fired ceramic and co-sintering, there is little reaction between materials and deviation in shrinkage behavior during firing, and defects such as delamination are unlikely to occur. The SiO ２ as the oxide (C1) of the ceramic crystal component can be distinguished from the SiO ２ contained in the fired glass component (A1).

[0026] The SiO as the oxide (C1) of the ceramic crystal component contained in the first low-temperature fired ceramic２ , BaAl ２ Si ２ O ８ , ZnAl ２ O ４ , Zn ２ SiO ４ and TiO ２ The preferred ratio is as follows: SiO ２ :0 weight% or more, 50 weight% or less BaAl ２ Si ２ O ８ : More than 0% by weight and 5% by weight or less ZnAl ２ O ４ :0 weight% or more, 30 weight% or less Zn ２ SiO ４ : 0% by weight or more and 25% by weight or less TiO ２ : 0% by weight or more, 10% by weight or less

[0027] BaAl contained in the first low-temperature fired ceramic ２ Si ２ O ８ The proportion is greater than 0% by weight and less than or equal to 5% by weight. BaAl ２ Si ２ O ８ If the ratio is within the above range, the rate of change in volume due to temperature (TCC) can be reduced. More preferably, it is greater than 0.1% by weight and less than or equal to 3% by weight.

[0028] BaAl ２ Si ２ O ８ This has the effect of increasing the positive TCC of low-temperature fired ceramics, while TiO ２ This has the effect of making the TCC of low-temperature fired ceramics significantly negative. The TCC of low-temperature fired ceramics is BaAl ２ Si ２ O ８ and TiO ２ It is possible to adjust the amount of TiO ２ As the amount increases, the relative permittivity increases, so when preparing low-dielectric ceramics, BaAl ２ Si ２ O ８It is preferable to adjust the TCC by reducing the amount of BaAl contained in the low dielectric constant ceramic. ２ Si ２ O ８ The proportion of TiO ２ If it does not contain [the specified substance], it is preferable that the amount is greater than 0% by weight and 5% by weight or less.

[0029] The proportion of the post-fired glass component (A1) and the oxide of the ceramic crystalline component (C1) contained in the first low-temperature fired ceramic is not particularly limited. For example, the proportion of the post-fired glass component (A1) contained in the low-dielectric constant ceramic can be 10% by weight or more and 55% by weight or less, and the proportion of the oxide of the ceramic crystalline component (C1) can be 45% by weight or more and 90% by weight or less.

[0030] The second low-temperature fired ceramic is a high-dielectric constant ceramic containing a glass component (A2) and an oxide (C2) of the ceramic crystal component after firing. The second low-temperature fired ceramic included in the electronic component of the present invention is a fired body obtained by firing a low-temperature co-fired ceramic (LTCC) material, which is a glass ceramic material that can be sintered at a firing temperature of 1000°C or lower. In this specification, the relative permittivity of the second low-temperature fired ceramic is greater than 7.

[0031] The glass component after firing (A2) is composed of SiO ２ and B ２ O ３ Except for the lack of a limit on the ratio of the proportions, it is the same as the post-fired glass component (A1) described above. For the second low-temperature fired ceramic, it is preferable that the proportion of the post-fired glass component is 10% by weight or more and 55% by weight or less, and the proportion of the oxide of the ceramic crystal component is 45% by weight or more and 90% by weight or less.

[0032] The second low-temperature fired ceramic uses Ba as the oxide (C2) of the ceramic crystal component. ２ Ti ９ O ２０ , BaTi(BO ３ ) ２ , BaTi ４ O ９ , BaTi ５ O １１ Ba ４ Ti１３ O ３０ BaZn ２ Ti ４ O １１ and Ba ４ ZnTi １１ O ２７ It includes at least one selected from the group consisting of the following. All of these oxides have high dielectric constants, which can make the dielectric constant of the calcined body greater than 7.

[0033] The second low-temperature fired ceramic is a form of the oxide (C2) of the ceramic crystal component, Ba ２ Ti ９ O ２０ The ratio, BaTi(BO ３ ) ２ The proportion of BaTi ４ O ９ The proportion of BaTi ５ O １１ The ratio, Ba ４ Ti １３ O ３０ The proportion of BaZn ２ Ti ４ O １１ The proportion and Ba ４ ZnTi １１ O ２７ The sum of the proportions is preferably 5% by weight or more, more preferably 30% by weight or more, and even more preferably 40% by weight or more. ２ Ti ９ O ２０ The ratio, BaTi(BO ３ ) ２ The proportion of BaTi ４ O ９ The proportion of BaTi ５ O １１ The ratio, Ba ４ Ti １３ O ３０ The proportion of BaZn ２ Ti ４ O １１ The proportion and Ba ４ ZnTi １１ O ２７ The sum of the proportions is preferably, for example, 90% by weight or less.

[0034] In the second low-temperature fired ceramic, the oxide (C2) of the ceramic crystalline component is further TiO ２ , BaAl ２ Si ２ O ８ , ZnAl ２ O ４ and Zn ２ SiO ４ It is preferable that the material contains at least two selected from the group consisting of the above. Including the above crystalline components reduces the differences in reactions between materials and shrinkage behavior during firing, making it less likely for defects such as delamination, pores, and cracks to occur.

[0035] The oxide (C2) component of the ceramic crystal is further TiO ２ , and also, BaAl ２ Si ２ O ８ , ZnAl ２ O ４ and Zn ２ SiO ４ It is more preferable to include at least one selected from the group consisting of BaAl. ２ Si ２ O ８ , ZnAl ２ O ４ and Zn ２ SiO ４ It exhibits the characteristic that its dielectric constant increases as the temperature rises, and TiO ２ This is because it exhibits the characteristic of decreasing dielectric constant as the temperature rises.

[0036] Ba as an oxide (C2) of the ceramic crystalline component contained in the second low-temperature fired ceramic ２ Ti ９ O ２０ , BaTi(BO ３ ) ２ , BaTi ４ O ９ , BaTi ５ O １１ Ba ４ Ti １３ O ３０ BaZn ２ Ti ４ O １１ Ba ４ ZnTi １１ O２７ , BaAl ２ Si ２ O ８ , ZnAl ２ O ４ , Zn ２ SiO ４ and TiO ２ The preferred ratio is as follows: Ba ２ Ti ９ O ２０ : 0% by weight or more and 55% by weight or less BaTi(BO ３ ) ２ : 0% by weight or more and 40% by weight or less BaTi ４ O ９ : 0% by weight or more and 35% by weight or less BaTi ５ O １１ : 0% by weight or more and 30% by weight or less Ba ４ Ti １３ O ３０ : 0% by weight or more and 30% by weight or less BaZn ２ Ti ４ O １１ : 0% by weight or more and 30% by weight or less Ba ４ ZnTi １１ O ２７ : 0% by weight or more and 25% by weight or less BaAl ２ Si ２ O ８ : 0% by weight or more and 40% by weight or less ZnAl ２ O ４ :0 weight% or more, 30 weight% or less Zn ２ SiO ４ : 0% by weight or more and 15% by weight or less TiO ２ : 0.1% by weight or more, 10% by weight or less

[0037] The following applies to both the first and second low-temperature fired ceramics. The low-temperature fired ceramic may further contain CuO and / or Cu. When the low-temperature fired ceramic contains CuO and / or Cu, during firing, BaO-ZnO-Al ２ O ３ -B ２ O ３ -SiO ２ BaAl from glass material ２ Si ２O ４ , ZnAl ２ O ４ , Zn ２ SiO ４ It promotes the precipitation of crystals, and BaO, ZnO and Al in the glass material. ２ O ３ The amount can be reduced. Preferably, the sum of the proportion of CuO and Cu contained in the low-temperature fired ceramic is 1% by weight or less. The proportion of CuO and Cu contained in the low-temperature fired ceramic is obtained by fluorescent X-ray analysis. When the firing of the low-temperature fired ceramic is carried out in an air atmosphere, it exists as CuO in the low-temperature fired ceramic, and when the firing is carried out in a reducing atmosphere, it exists as Cu.

[0038] As shown in Figure 1, the compositions of the multiple low-dielectric-constant ceramic layers 4 of the electronic component 200 may be the same or different, but it is preferable that they be the same. The compositions of the multiple high-dielectric-constant ceramic layers 5 may be the same or different, but it is preferable that they be the same.

[0039] As shown in Figures 1 and 2, the electronic component 200 has BaAl at the boundary between the low dielectric constant ceramic layer 4 and the high dielectric constant ceramic layer 5. ２ Si ２ O ８ The electronic component 200 includes a bonding layer 6 containing BaAl crystals. Because the bonding layer 6 is present, a strong bond is formed between the first low-temperature fired ceramic forming the low-dielectric-constant ceramic layer 4 and the second low-temperature fired ceramic forming the high-dielectric-constant ceramic layer 5. Even when the electronic component is subjected to impact, defects such as delamination and cracks are less likely to occur at the boundary between the low-dielectric-constant ceramic layer 4 and the high-dielectric-constant ceramic layer 5. Furthermore, the bonding layer 6 contains BaAl ２ Si ２ O ８ It is known to have good dielectric properties and is less likely to adversely affect circuit elements in electronic components.

[0040] The bonding layer 6 is made of BaAl ２ Si ２ O ８ It may also be formed only of crystals of BaAl２ Si ２ O ８ It may also contain other components or their crystals. The bonding layer 6 is BaAl ２ Si ２ O ８ It is preferable that the crystals contain 60% by weight or more, and more preferably 90% by weight or more.

[0041] The bonding layer has a thickness of 1 μm or more and less than 10 μm. If the bonding layer is less than 1 μm thick, the bonding strength between the low-dielectric-constant ceramic layer and the high-dielectric-constant ceramic layer is insufficient. If the bonding layer is 10 μm or more thick, it will affect the circuit elements of the low-dielectric-constant ceramic layer and the high-dielectric-constant ceramic layer. Preferably, the thickness is 5 μm or more and less than 10 μm thick.

[0042] The thickness of the bonding layer is determined as follows: As shown in Figure 2, first, the cross-sections (WT cross-sections) in the width (W) direction and stacking (T) direction, passing through the center in the length (L) direction of the electronic component, are exposed by polishing. If necessary, the polished surface is etched. Then, the exposed cross-sections are observed using a scanning electron microscope (SEM). The thickness of the bonding layer is uniform, and the bonding layer can be distinguished from the low-dielectric-constant ceramic layer and the high-dielectric-constant ceramic layer by observation with the SEM.

[0043] Draw a straight line Lc extending in the thickness direction T of the bonded layer in the exposed cross-section. Next, draw several straight lines parallel to line Lc at equal intervals. The interval between adjacent lines should be determined to be between 5 and 10 times the thickness of the bonded layer to be measured. Also, draw the same number of straight lines on both sides of line Lc. That is, draw an odd number of straight lines including line Lc. For example, draw three straight lines including line Lc.

[0044] Next, the thickness (t) of the bonding layer is measured along each straight line, such as line Lc. The average of these measurements is taken as the thickness of the bonding layer.

[0045] The number of low-dielectric-constant ceramic layers and high-dielectric-constant ceramic layers included in the laminate is not particularly limited. The arrangement of the low-dielectric-constant ceramic layers and high-dielectric-constant ceramic layers in the laminate is sufficient as long as the high-dielectric-constant ceramic layers are sandwiched between the low-dielectric-constant ceramic layers. In Figure 1, the low-dielectric-constant ceramic layer 4 and the high-dielectric-constant ceramic layer 5 are each laminated in two layers, but they may also be one layer each, or three or more layers each. The low-dielectric-constant ceramic layer 4 may be a single layer, or the high-dielectric-constant ceramic layer 5 may be a single layer. The high-dielectric-constant ceramic layer 5 may be present in two or more locations in the lamination direction (T).

[0046] Examples of electronic components of the present invention include a multilayer ceramic electronic component comprising a laminate, a multilayer ceramic substrate using the laminate, and a chip component mounted on the ceramic substrate.

[0047] A laminate comprising multiple low-temperature fired ceramic layers can be used, for example, as a ceramic multilayer substrate for communications or as a multilayer dielectric filter. The electronic component of the present invention has low dielectric loss and a high Q value, making it particularly suitable as an electronic component used in the millimeter-wave band. Even when subjected to impact, defects such as peeling or cracking are less likely to occur at the interface between the high-dielectric-constant ceramic layer and the low-dielectric-constant ceramic layer.

[0048] The laminate 100 may further have conductive layers, as shown in Figure 1. The conductive layers may constitute passive elements such as capacitors and inductors, or connecting wiring that provides electrical connections between elements. Such conductive layers include conductive layers 9, 10, 11 and via-hole conductive layer 12, as shown in Figure 1.

[0049] The conductor layers 9, 10, 11 and the via-hole conductor layer 12 preferably contain Ag or Cu as the main component. By using such low-resistance metals, the occurrence of signal propagation delay associated with the high frequency of electrical signals is prevented. Furthermore, since the low-dielectric-constant ceramic layer 4 and the high-dielectric-constant ceramic layer 5 are fired bodies produced by firing low-temperature co-fired ceramic (LTCC) material, they can be formed by co-firing with Ag and Cu.

[0050] The electronic component of the present invention preferably incorporates Cu wiring, and more preferably incorporates Cu wiring formed by co-firing of low-temperature co-firing ceramic (LTCC) material and Cu.

[0051] The conductive layer 9 is located inside the laminate 100. Specifically, the conductive layer 9 is located at the interfaces between the low dielectric constant ceramic layers 4, the interfaces between the high dielectric constant ceramic layers 5, and the interfaces between the low dielectric constant ceramic layer 4 and the high dielectric constant ceramic layer 5.

[0052] The conductive layer 10 is arranged on one of the main surfaces of the laminate 100.

[0053] The conductive layer 11 is arranged on the other main surface of the laminate 100.

[0054] The via-hole conductor layer 12 is arranged to penetrate the low-dielectric-constant ceramic layer 4 or the high-dielectric-constant ceramic layer 5, and plays a role in electrically connecting conductor layers 9 of different layers, electrically connecting conductor layers 9 and 10, or electrically connecting conductor layers 9 and 11.

[0055] The laminate 100 is manufactured, for example, as follows:

[0056] (A) Preparation of glass composition B ２ O ３ SiO ２ ZnO, Al ２ O ３ The glass composition is prepared by mixing the glass and BaO in a predetermined proportion. RO may be used if necessary.

[0057] (B) Preparation of glass powder The glass composition is melted, and the resulting molten material is rapidly cooled to produce cullet. The cullet is coarsely ground, and then further ground using a ball mill or the like to prepare glass powder having a predetermined particle size.

[0058] (C) Preparation of low-temperature co-fired ceramic (LTCC) material Low-temperature co-fired ceramic (LTCC) material is prepared by mixing glass powder and an oxide of the ceramic crystal component. When producing the first low-temperature fired ceramic, the oxide of the ceramic crystal component (C1) is BaAl ２ Si２ O ８ Using, and further SiO ２ , ZnAl ２ O ４ , Zn ２ SiO ４ and TiO ２ At least one selected from the group consisting of the following is used. When producing the second low-temperature fired ceramic, the oxide (C2) of the ceramic crystal component is Ba ２ Ti ９ O ２０ , BaTi(BO ３ ) ２ , BaTi ４ O ９ , BaTi ５ O １１ Ba ４ Ti １３ O ３０ BaZn ２ Ti ４ O １１ and Ba ４ ZnTi １１ O ２７ At least one selected from the group consisting of the following is used. The oxide (C2) of the ceramic crystal component is further BaAl ２ Si ２ O ８ , ZnAl ２ O ４ , Zn ２ SiO ４ and TiO ２ It is preferable to use at least two types selected from the group consisting of the following. The proportion of glass powder in the low-temperature co-fired ceramic (LTCC) material is preferably 10% by weight or more and 55% by weight or less.

[0059] (D) Preparation of Green Sheets Low-temperature co-fired ceramic (LTCC) material is mixed with a binder, plasticizer, etc. to prepare a ceramic slurry. Then, the ceramic slurry is molded onto a base film (for example, polyethylene terephthalate (PET) film) and dried to produce a green sheet.

[0060] (E) Fabrication of Laminated Green Sheets Laminated green sheets (unfired state) are fabricated by laminating green sheets. Figure 3 is a schematic cross-sectional view showing a laminated green sheet (unfired state) fabricated in the manufacturing process of the multilayer ceramic electronic component shown in Figure 1. As shown in Figure 3, the laminated green sheet 110 is made by laminating two layers of green sheets 23 for low dielectric constant ceramic layers, two layers of green sheets 24 for high dielectric constant ceramic layers, and then laminating two more layers of green sheets 23 for low dielectric constant ceramic layers. The green sheets 23 for low dielectric constant ceramic layers become low dielectric constant ceramic layers 4 after firing. The green sheets 24 for high dielectric constant ceramic layers become high dielectric constant ceramic layers 5 after firing. Conductor layers including conductor layers 9, 10, 11 and via-hole conductor layer 12 may be formed on the green sheets 23 for low dielectric constant ceramic layers and the green sheets 24 for high dielectric constant ceramic layers.

[0061] (F) Firing of the laminated green sheet The laminated green sheet 110 is fired. As a result, a laminate 100 as shown in Figure 1 is obtained. By firing, BaAl is produced from the first low-temperature fired ceramic. ２ Si ２ O ８ Crystals of BaAl precipitate at the boundary between the low dielectric constant ceramic layer 4 and the high dielectric constant ceramic layer 5. ２ Si ２ O ８ A bonding layer 6 containing crystals is formed.

[0062] The firing temperature of the laminated green sheet 110 is not particularly limited as long as it is a temperature at which the low-temperature co-firing ceramic (LTCC) materials constituting the green sheet 23 for the low-dielectric-constant ceramic layer and the green sheet 24 for the high-dielectric-constant ceramic layer can be sintered, and may be, for example, 1000°C or lower.

[0063] The firing atmosphere for the laminated green sheet 110 is not particularly limited, but when using materials that are difficult to oxidize, such as Ag, for the conductive layers 9, 10, 11 and the via-hole conductive layer 12, an air atmosphere is preferred, and when using materials that are easily oxidized, such as Cu, a low-oxygen atmosphere such as a nitrogen atmosphere is preferred. Furthermore, the firing atmosphere for the laminated green sheet 110 may also be a reducing atmosphere.

[0064] The laminated green sheet 110 may be fired while sandwiched between restraining green sheets. The restraining green sheet is an inorganic material (for example, Al) that does not substantially sinter at the sintering temperature of the low-temperature co-fired ceramic (LTCC) material constituting the green sheet 23 for the low-dielectric-constant ceramic layer and the green sheet 24 for the high-dielectric-constant ceramic layer. ２ O ３ It contains as its main component. Therefore, the restraining green sheet does not shrink when the laminated green sheet 110 is fired, and acts to suppress shrinkage in the main surface direction relative to the laminated green sheet 110. As a result, the dimensional accuracy of the resulting laminate 100 (especially the conductor layers 9, 10, 11 and the via-hole conductor layer 12) is improved.

[0065] Chip components 13 and 14 may be mounted on the laminate 100 in a state where they are electrically connected to the conductor layer 10. This constitutes an electronic component 200 having the laminate 100.

[0066] Examples of chip components 13 and 14 include LC filters, capacitors, inductors, and the like.

[0067] The electronic components 200 may be mounted on a substrate (e.g., a motherboard) so as to be electrically connected via the conductive layer 11.

[0068] In this specification, the composition of glass in the fired body is determined by wavelength-dispersive X-ray spectroscopy (WDS) analysis of glass regions identified by scanning transmission electron microscopy (STEM) and electron diffraction on a flake of the fired body sample. The crystal species and amount of crystals in the fired body are determined by XRD of the surface of the fired body sample for the low dielectric constant ceramic layer portion. For the high dielectric constant ceramic layer portion, the low dielectric constant ceramic layer is removed from the surface of the fired body sample by polishing, exposing the high dielectric constant ceramic layer, and the composition is determined by XRD of the surface.

[0069] The following are examples that more specifically disclose the low-temperature fired ceramics and electronic components of the present invention. However, the present invention is not limited to these examples.

[0070] Fabrication of High Dielectric Constant Ceramics (A) Preparation of Glass Powder The glass powders (all in powder form) that will be the glass components contained in samples No. H1 to H3 and H5 to H6 shown in Tables 1 and 2 were prepared by the following method. First, the glass raw material powders were mixed to obtain a glass composition. The glass composition was placed in a Pt crucible and melted in an air atmosphere at 1600°C for 30 minutes or more. Then, the obtained molten material was rapidly cooled to produce cullet. As a raw material for alkaline earth metal oxide (BaO), carbonate (BaCO3) was used. ３ ) was used. Carbonate (BaCO3) ３ The cullet is converted to alkaline earth metal oxide (BaO) upon calcination, and Table 2 shows the amount of BaO converted to the total amount. After coarse grinding the cullet, it was placed in a container with ethanol and PSZ balls (diameter: 5 mm) and mixed in a ball mill. By adjusting the grinding time during mixing in the ball mill, a glass powder with a median particle size of 1.0 μm was obtained. Here, "median particle size" refers to the median particle size D50 measured by laser diffraction and scattering.

[0071] The glass raw material powders (all in powder form) that constitute the glass component of sample No. H4 shown in Table 3 were prepared and pulverized until the median particle size was 1-2 μm to obtain glass powder. Sample No. H4 is the glass ceramic composition of sample number 50 in International Publication No. 2009 / 113475. In Tables 1, 2, and 3, samples marked with * are comparative examples.

[0072] (B) Preparation of high dielectric constant green sheets Next, glass powders of samples No. H1 to H6 shown in Tables 1, 2, and 3, and oxides of ceramic crystal components (central particle size 1.0 μm) were placed in ethanol and mixed in a ball mill. A binder solution of polyvinyl butyral dissolved in ethanol and a dioctyl phthalate (DOP) solution, which is a plasticizer, were then mixed to form a slurry. The slurry was formed onto a PET film using a doctor blade and dried at 40°C to obtain a high dielectric constant green sheet with a thickness of 50 microns. The proportions of glass powder and oxides of ceramic crystal components were adjusted so that the composition after firing matched the values ​​shown in Tables 1 and 2.

[0073] (C) Preparation and Evaluation of Samples for Evaluation 1. Relative Permittivity and Q Value As a sample for measuring relative permittivity and Q value, 20 sheets of green sheet were cut to 50 mm x 50 mm, stacked, placed in a mold, and pressed together with a press machine. This pressed body was fired in air at 900°C to 950°C for 60 minutes to obtain low-temperature fired ceramic. The relative permittivity and Q value (reciprocal of dielectric loss) of the obtained low-temperature fired ceramic were measured at 25°C and 3 GHz using the perturbation method. The measurement conditions were as follows: [Measurement equipment and measurement conditions] Network analyzer: Keysight 8757D Signal generator: Keysight synthesized sweeper 83751 Resonator: Self-made jig (resonance frequency: 3 GHz) Prior to the measurement, the network analyzer and signal generator were connected and cable loss was measured. Furthermore, the resonator was calibrated using a standard substrate (quartz, relative permittivity: 3.73, Q value: 9091 @ 3 GHz, thickness: 0.636 mm).

[0074] 2. Temperature Curve Coefficient (TCC) of Capacitance As a sample for evaluating TCC, 20 sheets of green sheet were cut to 10 mm x 10 mm and stacked, placed in a mold, and pressed together with a press machine. Pure Cu paste was printed on the entire surface of the upper and lower main surfaces of this pressed body as the counter electrodes for the capacitor. After drying, it was fired in a reducing atmosphere at 900°C to 950°C for 60 minutes. After firing, the sample was placed in a temperature bath and the relative permittivity was measured using an LCR meter (Agilent, model number: E4980A) in the range of -40°C to 125°C to determine the temperature curve coefficient (TCC) of capacitance and evaluate the temperature dependence of the relative permittivity. These results are shown in Tables 1 and 2.

[0075]

[0076]

[0077]

[0078] Fabrication of Low Dielectric Constant Ceramics (A) Preparation of Glass Samples No. L1 to L3 shown in Tables 4 and 5 and sample numbers L4 to L5 shown in Table 6 (all in powder form) were prepared using the same method as in "(A) Preparation of Glass Powder" for the fabrication of high dielectric constant ceramics. Samples No. L4 to L5 are the glass ceramic compositions of sample numbers 101 and 102 in International Publication No. 2009 / 113475, respectively. In Tables 4, 5, and 6, samples marked with * are comparative examples.

[0079] (B) Preparation of low dielectric constant green sheets Next, low dielectric constant green sheets were obtained in the same manner as in "(B) Preparation of high dielectric constant green sheets" in the preparation of high dielectric constant ceramics, except that glass powder and oxides of ceramic crystalline components (central particle size 1.0 μm) were used in the combinations shown in Tables 4, 5, and 6.

[0080] (C) Preparation of evaluation samples and evaluation Low-temperature fired ceramics were obtained using the same method as in "(C) Preparation and evaluation of evaluation samples" in the preparation of high-dielectric constant ceramics, and the relative permittivity, Q value, TCC, and composition of the obtained low-temperature fired ceramics were determined. These results are shown in Tables 4 and 5.

[0081]

[0082]

[0083]

[0084] Samples for evaluating the sinterability of electronic components comprising a high-dielectric-constant ceramic layer and a low-dielectric-constant ceramic layer were prepared using the following procedure. The high-dielectric-constant and low-dielectric-constant green sheets prepared above were cut to 50 mm x 50 mm, and stacked in the order of eight low-dielectric-constant green sheets, four high-dielectric-constant green sheets, and eight low-dielectric-constant green sheets as shown in Table 7. These were placed in a mold and pressed together using a press machine. This pressed body was fired in a reducing atmosphere at 900°C to 950°C for 60 minutes to obtain a fired body. In Table 7, samples marked with * are comparative examples.

[0085] The resulting fired body was embedded in resin and hardened. The cross-section was then polished, and the boundary between the high-dielectric-constant ceramic layer and the low-dielectric-constant ceramic layer was observed using a scanning electron microscope (SEM) to check for defects such as delamination, pores, and cracks. Furthermore, if a bonding layer was formed at the boundary between the high-dielectric-constant ceramic layer and the low-dielectric-constant ceramic layer, its thickness was measured. The results are shown in Table 7.

[0086] For samples without defects at the boundary, a drop test was conducted by dropping the fired body from a height of 1 m onto concrete. The boundary between the high-dielectric-constant ceramic layer and the low-dielectric-constant ceramic layer of the fired body was observed using a scanning electron microscope (SEM) to check for defects such as delamination and cracks. The results are shown in Table 7.

[0087]

[0088] As shown in Table 7, in all of the electronic components of the present invention (samples No. S1, S4, and S8), no peeling or cracking defects occurred after the drop test, and a bonding layer was observed between the high-dielectric-constant ceramic layer and the low-dielectric-constant ceramic layer, indicating that a strong bond was achieved. In sample No. S8, the second low-temperature fired ceramic H5 constituting the high-dielectric-constant ceramic layer is Ba ２ Ti ９ O ２０ The ratio, BaTi(BO ３ ) ２ The proportion of BaTi ４ O ９ The proportion of BaTi ５ O １１ The ratio, Ba ４ Ti １３ O ３０ The proportion of BaZn ２ Ti ４ O １１ The proportion and Ba ４ ZnTi １１ O ２７ Since the sum of the proportions was 40% by weight or less, the bonding layer was thinner compared to samples No. S1 and S4. Among the comparative electronic components (samples No. S2-S3, S5-S7, S9), in samples No. S2-S3 and S5, the first low-temperature fired ceramic L2 constituting the low-dielectric constant ceramic layer was BaAl ２ Si ２ O ８Because it did not contain BaO, or because the glass component of L3 did not contain BaO, there was a defect between the high-dielectric-constant ceramic layer and the low-dielectric-constant ceramic layer. Samples No. S6 to S7, which used the glass-ceramic composition of International Publication No. 2009 / 113475, showed no defects between the high-dielectric-constant ceramic layer and the low-dielectric-constant ceramic layer after co-sintering, but after the drop test, peeling and cracking occurred at the boundary between the high-dielectric-constant ceramic layer and the low-dielectric-constant ceramic layer, indicating insufficient bonding strength. In sample No. S9, the proportion of BaO in the post-sintered glass component (A2) contained in the high-dielectric-constant ceramic layer was greater than 10 mol%, which is thought to have resulted in a larger bonding layer thickness.

[0089] In the examples, the composition of the glass in the fired body was determined by wavelength-dispersive X-ray spectroscopy (WDS) analysis of the glass region identified by scanning transmission electron microscopy (STEM) and electron diffraction on the exfoliated fired body sample. The crystal species and amount of crystals in the fired body were determined by XRD of the surface of the fired body sample for the low dielectric constant ceramic layer portion. For the high dielectric constant ceramic layer portion, the low dielectric constant ceramic layer was removed from the surface of the fired body sample by polishing, exposing the high dielectric constant ceramic layer, and its composition was determined by XRD of the surface.

[0090] 4 Low dielectric constant ceramic layer 5 High dielectric constant ceramic layer 6 Bonding layer 9, 10, 11 Conductor layer 12 Via hole conductor layer 13, 14 Chip component 23 Green sheet for low dielectric constant ceramic layer 24 Green sheet for high dielectric constant ceramic layer 100 Laminate 110 Laminated green sheet 200 Electronic component

Claims

1. An electronic component comprising a low dielectric constant ceramic layer and a high dielectric constant ceramic layer, wherein the low dielectric constant ceramic layer is formed of a first low-temperature fired ceramic, the high dielectric constant ceramic layer is formed of a second low-temperature fired ceramic, the first low-temperature fired ceramic contains a fired glass component (A1) and an oxide (C1) of a ceramic crystal component, the second low-temperature fired ceramic contains a fired glass component (A2) and an oxide (C2) of a ceramic crystal component, the fired glass component (A1) and the fired glass component (A2) are BaO-ZnO-Al ２ O ３ -B ２ O ３ -SiO ２ and the ratios of BaO, ZnO, and Al ２ O ３ contained in the fired glass component (A1) and the fired glass component (A2) are each 0.1 mol% or more and 10 mol% or less, and the sum of the ratios of BaO, ZnO, and Al ２ O ３ contained in each of the fired glass component (A1) and the fired glass component (A2) is 15 mol% or less. The ratio of SiO ２ to B ２ O ３ in the fired glass component (A1) (SiO ２ / B ２ O ３ ) is less than 3.

4. The oxide (C1) of the ceramic crystal component contains BaAl ２ Si ２ O ８ and further contains at least two selected from the group consisting of SiO ２ , ZnAl ２ O ４ , Zn ２ SiO ４ and TiO ２ . The BaAl ２ Si ２ O ８ The proportion of is greater than 0% by weight and 5% by weight or less, and the oxide (C2) of the ceramic crystal component is Ba ２ Ti ９ O ２０ , BaTi(BO ３ ) ２ , BaTi ４ O ９ , BaTi ５ O １１ Ba ４ Ti １３ O ３０ BaZn ２ Ti ４ O １１ and Ba ４ ZnTi １１ O ２７ It includes at least one selected from the group consisting of the following, and at the boundary between the low dielectric constant ceramic layer and the high dielectric constant ceramic layer, BaAl ２ Si ２ O ８ An electronic component comprising a bonding layer containing a crystal, wherein the bonding layer has a thickness of 1 μm or more and less than 10 μm.

2. The post-fired glass component (A1) and the post-fired glass component (A2) further contain RO, the RO is at least one selected from the group consisting of MgO, CaO and SrO, the proportion of RO contained in the post-fired glass component (A1) and the post-fired glass component (A2) is 0.1 mol% or more and 10 mol% or less, and the proportion of BaO, the proportion of RO, the proportion of ZnO and the Al contained in the post-fired glass component (A1) and the post-fired glass component (A2) respectively. ２ O ３ The electronic component according to claim 1, wherein the sum of the proportions is 15 mol% or less.

Images