Glass ceramic structures and electronic components

Abstract

A glass ceramic structure 100 has first ceramic layers 11 which each contain a crystal 13, and a second ceramic layer 12 which contains the crystal 13 and has a different content of the crystal 13 from the first ceramic layers 11, the glass ceramic structure 100 being characterized in that: the second ceramic layer 12 is present on a surface of the glass ceramic structure 100, or alternatively is present between the first ceramic layers 11 in the thickness direction; the relationship between a shortest distance D1 in the thickness direction from the surface of the glass ceramic structure 100 to the second ceramic layer 12 and a layer thickness t of the second ceramic layer 12 satisfies (shortest distance from surface) / (layer thickness of second ceramic layer) ≤ 10; the composition of the first ceramic layers 11 contains 45% by weight to 77.5% by weight of SiO2, 5% by weight to 20% by weight of B2O3, 2.6% by weight to 20% by weight of Al2O3, 2.7% by weight to 20% by weight of ZnO, 0% by weight to 3.4% by weight of CuO, and 0% by weight to 10% by weight of BaO; the crystal 13 is composed of at least one substance that is selected from the group consisting of Al2O3, ZnSi2O4, ZnO, ZnAl2O4, BaAl2Si2O8, ZnTiO3, Al2TiO5, TiO2, Mg2SiO4, MgSiO3, and MgO; the ratio of the cross-sectional area occupied in a ceramic cross-section by the crystal 13 present in the second ceramic layer 12 is larger than the ratio of the cross-sectional area occupied in the ceramic cross-section by the crystal 13 present in the first ceramic layer 11, the difference therebetween being 10% by area to 75% by area.

Description

Technical Field

[0001] The present invention relates to a glass-ceramics structure and an electronic component.

Background Art

[0002] Since a low-temperature sintering ceramic material can be co-fired with a low-melting-point metal material having a relatively small specific resistance, a multilayer ceramic substrate excellent in high-frequency characteristics can be formed, and it is widely used as a substrate material for high-frequency modules in information communication terminals and the like.

[0003] As the low-temperature sintering ceramic material, a glass-ceramics composite material in which a B2O3-SiO2-based glass material is mixed with a ceramic material such as Al2O3 is common. However, since it contains boron which is likely to volatilize during firing, the composition of the obtained substrate is likely to vary. To solve this problem, a non-glass-based low-temperature sintering ceramic material containing no boron has been proposed. However, a ceramic sintered body obtained by sintering such a low-temperature sintering ceramic material may not obtain desirable strength characteristics because its fracture toughness value is small.

[0004] In Patent Document 1, a ceramic sintered body is disclosed which contains each crystal phase of Quartz, Alumina, Fresnoite, Sanbornite, and Celsian, and the relationship between the diffraction peak intensity A of the (201) plane of the Fresnoite and the diffraction peak intensity B of the (110) plane of the Quartz measured in the range of diffraction peak angle 2θ = 10 to 40° by powder X-ray diffraction method is A / B ≧ 2.5.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] In Patent Document 1, the strength of a ceramic sintered body is increased by precipitating crystals such as fresnoite and celsian throughout the ceramic layer. However, because crystals are precipitated throughout the entire structure, the electrical properties are limited to a certain extent, and it is not possible to apply stress to specific parts of the ceramic sintered body. Furthermore, because the sintered body in Patent Document 1 has a distinctive material composition, it is necessary to change the composition of the glass ceramic material in order to impart strength.

[0007] The present invention aims to solve the above problems and to provide glass-ceramic structures and electronic components that are locally equipped with fracture toughness. [Means for solving the problem]

[0008] The first glass-ceramic structure of the present invention is a glass-ceramic structure having a first ceramic layer containing crystals and a second ceramic layer containing crystals, wherein the crystal content differs from that of the first ceramic layer, the second ceramic layer is located on the surface of the glass-ceramic structure or is located between the first ceramic layers in the thickness direction, and the relationship between the shortest distance in the thickness direction from the surface of the glass-ceramic structure to the second ceramic layer and the thickness of the second ceramic layer is (shortest distance from the surface) / (thickness of the second ceramic layer) ≤ 10, the composition of the first ceramic layer is SiO2: 45% by weight or more, 77.5% by weight or less, B2O3: 5% by weight or more, 20% by weight or less, Al2O3: 2.6% by weight or more, 20% by weight or less, ZnO: 2.7% by weight or more, 20% by weight or less, CuO: 0% by weight or more, 3.4% by weight or less, BaO: 0% by weight or more, 10% by weight or less, and the crystals are Al2O3, Zn 2 SiO4. At least one selected from the group consisting of ZnO, ZnAl2O4, BaAl2Si2O8, ZnTiO3, Al2TiO5, TiO2, Mg2SiO4, MgSiO3, and MgO, characterized in that the ratio of the cross-sectional area of ​​the crystals present in the second ceramic layer to the ceramic cross-section is greater than the ratio of the cross-sectional area of ​​the crystals present in the first ceramic layer to the ceramic cross-section, and the difference is between 10 area% and 75 area%.

[0009] The second glass-ceramic structure of the present invention is a glass-ceramic structure having a plurality of first ceramic layers containing crystals, a second ceramic layer containing crystals and having a different crystal content from the first ceramic layers, and an internal electrode, wherein the second ceramic layer is located between the first ceramic layers in the thickness direction, or is located on the surface of the glass-ceramic structure, and the second ceramic layer and the internal electrode are adjacent in the thickness direction, or the first ceramic layer is located between the second ceramic layer and the internal electrode in the thickness direction. Furthermore, the relationship between the shortest distance in the thickness direction from the internal electrode to the second ceramic layer and the thickness of the second ceramic layer is (shortest distance from the internal electrode) / (thickness of the second ceramic layer) ≤ 10, and the composition of the first ceramic layer is SiO2: 45% or more by weight, 77.5% or less by weight, B2O3: 5% or more by weight, 20% or less by weight, Al2O3: 2.6% or more by weight, 20% or less by weight, ZnO: 2.7% or more by weight, 20% or less by weight, CuO: 0% or more by weight, 3.4% or less by weight, BaO: 0% or more by weight, 10% or less by weight, and the crystal is Al2O3, Zn 2 SiO 4. At least one selected from the group consisting of ZnO, ZnAl2O4, BaAl2Si2O8, ZnTiO3, Al2TiO5, TiO2, Mg2SiO4, MgSiO3, and MgO, characterized in that the ratio of the cross-sectional area of ​​the crystals present in the second ceramic layer to the ceramic cross-section is greater than the ratio of the cross-sectional area of ​​the crystals present in the first ceramic layer to the ceramic cross-section, and the difference is between 10 area% and 75 area%.

[0010] The electronic component of the present invention includes the glass-ceramic structure described above. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide glass-ceramic structures and electronic components that are locally equipped with fracture toughness. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of the first glass-ceramic structure. [Figure 2] Figure 2 is a schematic cross-sectional view showing another example of the first glass-ceramic structure. [Figure 3A] Figure 3A is a schematic cross-sectional view showing an example of the crystal distribution in the glass-ceramic structure shown in Figure 1. [Figure 3B] Figure 3B is a schematic cross-sectional view showing another example of the crystal distribution in the glass-ceramic structure shown in Figure 1. [Figure 3C] Figure 3C is a schematic cross-sectional view showing another example of the crystal distribution in the glass-ceramic structure shown in Figure 1. [Figure 4] Figure 4 is a schematic cross-sectional view showing an example of a second glass-ceramic structure. [Figure 5] Figure 5 is a schematic cross-sectional view showing an example of an electronic component. [Figure 6] Figure 6 is a perspective view showing the method for measuring the flexural strength of the glass-ceramic structure fabricated in the example. [Figure 7] Figure 7 is a schematic cross-sectional view used to evaluate the strength of the glass-ceramic structure fabricated in the example. [Figure 8] Figure 8 is a schematic cross-sectional view used to evaluate the strength of the glass-ceramic structure fabricated in the example. [Modes for carrying out the invention]

[0013] Hereinafter, the first glass-ceramics structure, the second glass-ceramics structure, and the electronic component of the present invention will be described. Note that the present invention is not limited to the following configurations, and may be appropriately modified without departing from the gist of the present invention. Also, combinations of a plurality of the individual preferred configurations described below are also within the scope of the present invention.

[0014] The first glass-ceramics structure of the present invention has a first ceramics layer containing crystals and a second ceramics layer containing crystals with a different crystal content from the first ceramics layer, and the second ceramics layer exists between the first ceramics layers in the thickness direction or exists on the surface of the glass-ceramics structure. In the first glass-ceramics structure, the first ceramics layer is the main body.

[0015] FIG. 1 is a schematic cross-sectional view showing an example of the first glass-ceramics structure. The glass-ceramics structure 100 shown in FIG. 1 is formed by laminating three first ceramics layers 11 and two second ceramics layers 12. In FIG. 1, the second ceramics layer 12 with a layer thickness t (μm) is disposed at a position with the shortest distance D1 from one main surface 100a of the glass-ceramics structure 100, and another second ceramics layer 12 is disposed at a position with the shortest distance D1 from the other main surface 10b of the glass-ceramics structure 100.

[0016] The second ceramics layer may be two layers, one layer, or three or more layers. The first glass-ceramics structure preferably has two second ceramics layers.

[0017] The relationship between the shortest distance in the thickness direction from the surface of the first glass-ceramics structure to the second ceramics layer (hereinafter sometimes referred to as "the shortest distance from the surface") and the layer thickness of the second ceramics layer is (the shortest distance from the surface) / (the layer thickness of the second ceramics layer) ≤ 10. By satisfying the above formula, the first glass-ceramics structure is imparted with higher fracture toughness at the position where the second ceramics layer is formed.

[0018] The shortest distance from the surface and the thickness of the second ceramic layer are determined as follows: As shown in Figure 1, first, the cross-sections (WT cross-sections) in the width (W) and stacking (T) directions, passing through the center in the length (L) direction of the glass-ceramic structure, are exposed by polishing. If necessary, the polished surface is etched. Then, the exposed cross-sections are observed using a scanning electron microscope.

[0019] A straight line Lc is drawn extending in the stacking direction T of the first and second ceramic layers and passing through the center of the glass-ceramic structure. Next, several straight lines are drawn at equal intervals parallel to line Lc. The interval between adjacent lines should be determined to be between 5 and 10 times the thickness of the second ceramic layer to be measured. Also, the same number of straight lines are drawn on both sides of line Lc. That is, an odd number of straight lines are drawn in total, including line Lc. For example, three straight lines are drawn in total, including line Lc.

[0020] Next, the shortest distance from the surface and the thickness of the second ceramic layer are measured along each straight line, such as line Lc. However, if the second ceramic layer is missing along each straight line, and the first ceramic layers sandwiching this second ceramic layer are connected, or if the magnified image of the measurement position is unclear, the shortest distance from the surface and the thickness of the second ceramic layer are measured along a straight line further away from line Lc. The average values ​​of these measurements are taken as the shortest distance from the surface and the thickness of the second ceramic layer.

[0021] When the shortest distance in the thickness direction from the surface of the first glass-ceramic structure to the second ceramic layer (shortest distance from the surface) is 0, the second ceramic layer is located on the surface of the first glass-ceramic structure (Figure 2). Figure 2 is a schematic cross-sectional view showing another example of the first glass-ceramic structure. In Figure 2, two second ceramic layers 12 are arranged on two main surfaces of the glass-ceramic structure 110.

[0022] The shortest distance in the thickness direction from the surface of the first glass-ceramic structure to the second ceramic layer is preferably, for example, 0 μm or more and 150 μm or less, and more preferably 0 μm or more and 120 μm or less. The thickness of the second ceramic layer is preferably, for example, 3 μm or more and 75 μm or less, and more preferably 5 μm or more and 60 μm or less. The shortest distance and the thickness of the second ceramic layer are not limited to the above range, but can be adjusted to satisfy the above formula. Note that if the shortest distance is 0, that is, if the second ceramic layer is on the surface of the first glass-ceramic structure, the value of (shortest distance from the surface) / (thickness of the second ceramic layer) will always be 0 regardless of the thickness of the second ceramic layer. In this case, the thickness of the second ceramic layer is preferably 3 μm or more and 75 μm or less.

[0023] The composition of the first ceramic layer described above is as follows: SiO2: 45% or more by weight, 77.5% or less by weight; B2O3: 5% or more by weight, 20% or less by weight; Al2O3: 2.6% or more by weight, 20% or less by weight; ZnO: 2.7% or more by weight, 20% or less by weight; CuO: 0% or more by weight, 3.4% or less by weight; BaO: 0% or more by weight, 10% or less by weight. The above composition is calculated on an oxide basis.

[0024] The second ceramic layer (also called the crystalline layer) has a non-crystalline portion with the same composition range as the first ceramic layer described above, but differs in its crystal content, with the second ceramic layer containing more crystals. The type of crystals with differing content is not particularly limited; they may be crystals contained in the first ceramic layer, crystals contained only in the second ceramic layer and not in the first, or both.

[0025] Examples of crystals included in the first ceramic layer include Al2O3 and ZnO. Examples of crystals found only in the second ceramic layer include: Zn 2 SiOExamples include ZnAl2O4, BaAl2Si2O8, ZnTiO3, Al2TiO5, TiO2, Mg2SiO4, MgSiO3, and MgO.

[0026] Crystals in which the content differs between the first and second ceramic layers are Al2O3. Zn 2 SiO 4. At least one selected from the group consisting of ZnO, ZnAl2O4, BaAl2Si2O8, ZnTiO3, Al2TiO5, TiO2, Mg2SiO4, MgSiO3, and MgO. The crystals with different content may be one type or two or more types, but two or more types are preferable.

[0027] The proportion of the cross-sectional area of ​​crystals present in the second ceramic layer to the total ceramic cross-section is greater than the proportion of the cross-sectional area of ​​crystals present in the first ceramic layer, and the difference (hereinafter sometimes referred to as difference (d1)) is between 10 area% and 75 area%. Here, the cross-sectional area of ​​the crystal is not the cross-sectional area of ​​a specific type of crystal, but the sum of the cross-sectional areas of all types of crystals. Since the above difference (d1) is a comparison of the cross-sectional areas of all types of crystals, the proportion of a specific type of crystal in the second ceramic layer may be less than the proportion of the same specific type of crystal in the first ceramic layer.

[0028] The proportion of the cross-sectional area of ​​crystals within a ceramic cross-section can be calculated, for example, as follows: First, the sample cross-section is observed using a scanning electron microscope (SEM) and an X-ray diffraction analyzer (XRD), and the crystalline and amorphous regions are marked with specific colors. The marked crystalline regions are extracted using image analysis software or image editing software (such as Photoshop® or ImageJ), and after undergoing black and white binarization, the cross-sectional areas of the crystalline and amorphous regions are determined. Dividing the cross-sectional area of ​​the crystalline regions by the sum of the cross-sectional areas of the crystalline and amorphous regions gives the proportion of the cross-sectional area of ​​crystals within the ceramic cross-section.

[0029] When the above difference (d1) is between 10 area% and 75 area%, the flexural strength of the glass-ceramic structure improves compared to when the above difference (d1) is outside the above range.

[0030] Figure 3A is a schematic cross-sectional view showing an example of the crystal distribution in the glass-ceramic structure shown in Figure 1. Figure 3B is a schematic cross-sectional view showing another example of the crystal distribution in the glass-ceramic structure shown in Figure 1. Figure 3C is a schematic cross-sectional view showing yet another example of the crystal distribution in the glass-ceramic structure shown in Figure 1. In the glass-ceramic structure 100A shown in Figure 3A, the crystals 13a present in the second ceramic layer 12 are also present in the first ceramic layer 11, and the second ceramic layer 12 contains more crystals.

[0031] In the glass-ceramic structure 100B shown in Figure 3B, of the crystals 13a and 13b present in the second ceramic layer 12, crystal 13a is also present in the first ceramic layer 11, and more crystals are contained in the second ceramic layer 12. Crystal 13b is not present in the first ceramic layer 11, but is present only in the second ceramic layer 12. If the above difference (d1) is within the above range, then crystal 13a may be present in greater quantities in the first ceramic layer 11 than in the second ceramic layer 12, or crystal 13a may not be present in the second ceramic layer 12 at all.

[0032] In the glass-ceramic structure 100C shown in Figure 3C, of ​​the crystals 13a, 13b, 13c, and 13d present in the second ceramic layer 12, crystal 13a is also present in the first ceramic layer 11, and more crystals are contained in the second ceramic layer 12. Crystals 13b, 13c, and 13d are not present in the first ceramic layer 11, but are present only in the second ceramic layer 12. If the above difference (d1) is within the above range, crystal 13a may be present in greater quantities in the first ceramic layer 11 than in the second ceramic layer 12, or crystal 13a may not be present in the second ceramic layer 12 at all.

[0033] In Figures 3A, 3B, and 3C, only crystal 13a is present in the first ceramic layer 11, but two or more types of crystals may be present in the first ceramic layer 11. Also, four or more types of crystals may be present in the second ceramic layer 12.

[0034] The first glass-ceramic structure can be fabricated, for example, by the following method. (1) Preparation of Green Sheet A A glass-ceramic material that will become the first ceramic layer of the first glass-ceramic structure is mixed with a binder, plasticizer, etc. to prepare a ceramic slurry A. Then, the ceramic slurry A is molded onto a base film (for example, polyethylene terephthalate (PET) film) and dried to produce a green sheet A.

[0035] (2) Preparation of Green Sheet B A mixed raw material is prepared by mixing the glass ceramic material used in the production of Green Sheet A with at least one filler component selected from the group consisting of Al2O3, BaTiO3, ZnO, and Mg2SiO4. As the proportion of filler component in the mixed raw material increases, more crystals precipitate in the second ceramic layer; therefore, the amount of filler component is adjusted according to the desired proportion of crystals. The mixed raw materials are mixed with a binder, plasticizer, etc. to prepare ceramic slurry B. Then, after forming ceramic slurry B onto a base film, green sheet B is produced by drying.

[0036] (3) Preparation and firing of laminated green sheets Green sheets A are stacked, and green sheet B is placed on the surface of the stack, or green sheet B is sandwiched between green sheets A to create a stacked green sheet. The stacked green sheets A and B are then fired to react, causing crystals to form on the entire or a part of the stacked surface of green sheet B. As a result, a second ceramic layer is formed at the location of green sheet B, and a glass-ceramic structure (multilayer ceramic substrate) as shown in Figure 1 or Figure 2 is obtained.

[0037] When Al2O3 is used as a filler component, the amount of Al2O3, BaAl2Si2O8, and ZnAl2O4 crystals increases in the second ceramic layer. When ZnO is used as a filler component, the second ceramic layer contains ZnAl2O3, ZnO and Zn 2 SiO The number of crystals increases by 4. When Mg2SiO4 is used as a filler component, the amount of Mg2SiO4, MgSiO3, and MgO crystals increases in the second ceramic layer. When BaTiO3 is used as a filler component, the amount of ZnTiO3, Al2TiO5, BaAl2Si2O8, and TiO2 crystals increases in the second ceramic layer.

[0038] Compounds in which the filler component BaTiO3 is replaced with other alkaline earth metals can also be used as substitutes because they precipitate crystals with the same basic structure.

[0039] In addition to using Green Sheet B, it is also possible to create a second ceramic layer on the surface or inside of a glass-ceramic structure by forming a pattern on Green Sheet A with ceramic slurry B, which is the raw material for Green Sheet B, and then firing the resulting laminate obtained by stacking the Green Sheet A with the pattern formed on it. Methods for forming the pattern include metal mask printing, chemical etching using chemicals, physical etching such as laser processing, inkjet printing, and spray coating.

[0040] The firing temperature of the laminated green sheets is not particularly limited as long as it is a temperature at which the glass ceramic materials constituting green sheet A and green sheet B can be fired, for example, 1000°C or lower. The glass ceramic material used in this invention is a low-temperature co-fired ceramic (LTCC) material.

[0041] Furthermore, the laminated green sheets may be fired while sandwiched between restraining green sheets. The restraining green sheets mainly contain inorganic materials (e.g., Al2O3) that are not substantially fired at the firing temperature of the glass ceramic materials constituting green sheet A and green sheet B. Therefore, the restraining green sheets do not shrink during the firing of the laminated green sheets and act to suppress shrinkage in the main plane direction relative to the laminated green sheets. As a result, the dimensional accuracy of the resulting structure is improved.

[0042] The first glass-ceramic structure, having the above-described structure, is endowed with high fracture toughness at the location where the second ceramic layer is formed. By concentrating crystal deposition on the surface in the thickness direction of the glass-ceramic structure, or at least a portion of the area near the surface in the thickness direction, compressive and tensile stresses can be generated at various points within the second ceramic layer. This distributes stress against localized loads, thereby increasing fracture toughness.

[0043] Next, we will describe the second type of glass-ceramic structure. The second glass-ceramic structure of the present invention is a glass-ceramic structure having a plurality of first ceramic layers containing crystals, a second ceramic layer containing crystals and having a different crystal content from the first ceramic layers, and an internal electrode, wherein the second ceramic layer is located between the first ceramic layers in the thickness direction or on the surface of the glass-ceramic structure, the second ceramic layer and the internal electrode are adjacent in the thickness direction, or the first ceramic layer is located between the second ceramic layer and the internal electrode in the thickness direction. In the second glass-ceramic structure, the first ceramic layer is the main element.

[0044] Figure 4 is a schematic cross-sectional view showing an example of a second glass-ceramic structure. The glass-ceramic structure 200 shown in Figure 4 is made up of multiple layers of first ceramic layers 11 and second ceramic layers 12 (in Figure 4, there are four first ceramic layers and two second ceramic layers). The second ceramic layers 12 are located on the surface of the glass-ceramic structure 200 in the thickness direction.

[0045] The second ceramic layer may consist of two layers, one layer, or three or more layers. Preferably, the second glass-ceramic structure has two second ceramic layers.

[0046] The glass-ceramic structure 200 has multiple layers of internal electrodes 21. The internal electrodes 21 are positioned between two adjacent first ceramic layers 11 in the thickness direction, or between an adjacent first ceramic layer 11 and a second ceramic layer 12 in the thickness direction. In Figure 4, a second ceramic layer 12 with a thickness t (μm) is positioned at the shortest distance D2 from the internal electrode 21 in the thickness direction, and a first ceramic layer 11 exists between the second ceramic layer 12 and the internal electrode 21. Another second ceramic layer 12 is positioned adjacent to the internal electrode 21 in the thickness direction in part.

[0047] The glass-ceramic structure 200 has via conductors 22 and external electrodes 23 and 24 formed on it. These can, for example, constitute passive elements such as capacitors and inductors, or they can constitute connecting wiring that provides electrical connections between elements.

[0048] The external electrode 23 is positioned on one main surface of the glass-ceramic structure 200. The external electrode 24 is positioned on the other main surface of the glass-ceramic structure 200.

[0049] The via conductor 22 is positioned to penetrate the first ceramic layer 11 and the second ceramic layer 12, and plays a role in electrically connecting the internal electrode 21 and the external electrodes 23 and 24. The via conductor 22 may also be positioned to electrically connect two internal electrodes 21.

[0050] In the second glass-ceramic structure, the relationship between the shortest distance in the thickness direction from the internal electrode to the second ceramic layer and the thickness of the second ceramic layer is (shortest distance from the internal electrode) / (thickness of the second ceramic layer) ≤ 10. By satisfying the above equation, the second glass-ceramic structure is given high fracture toughness at the location where the second ceramic layer is formed.

[0051] The thickness of the second ceramic layer can be determined in the same way as the first glass-ceramic structure.

[0052] When the shortest distance in the thickness direction from the internal electrode to the second ceramic layer (shortest distance from the internal electrode) is 0, the second ceramic layer is in contact with the internal electrode in the thickness direction.

[0053] The shortest distance in the thickness direction from the internal electrode to the second ceramic layer is preferably, for example, 0 μm or more and 150 μm or less, and more preferably 0 μm or more and 120 μm or less. The thickness of the second ceramic layer is preferably, for example, 3 μm or more and 75 μm or less, and more preferably 5 μm or more and 60 μm or less. The shortest distance from the internal electrode and the thickness of the second ceramic layer are not limited to the above ranges, but should be adjusted to satisfy the above formula. Note that if the shortest distance is 0, that is, if the second ceramic layer is in contact with the internal electrode, the value of (shortest distance from the internal electrode) / (thickness of the second ceramic layer) will always be 0 regardless of the thickness of the second ceramic layer. In this case, the thickness of the second ceramic layer is preferably 3 μm or more and 75 μm or less.

[0054] The composition of the amorphous portions of the first and second ceramic layers, the composition of the crystals, and the crystal content ratio can be the same as those of the first glass-ceramic structure.

[0055] In the second glass-ceramic structure, the proportion of the cross-sectional area of ​​crystals present in the second ceramic layer to the ceramic cross-section is greater than the proportion of the cross-sectional area of ​​crystals present in the first ceramic layer to the ceramic cross-section, and the difference (d2) is between 10 area% and 75 area%. When the above difference (d2) is between 10 area% and 75 area%, structural defects occurring around the internal electrodes and their deterioration can be suppressed compared to when the above difference (d2) is outside the above range.

[0056] Internal electrodes, via conductors, and external electrodes can be formed using a conductive paste containing Ag or Cu. In the second glass-ceramic structure, it is preferable that the main component of the internal electrodes, via conductors, and external electrodes is Cu. The internal electrodes, via conductors, and external electrodes can be formed by printing using a metal mask or by transferring and laminating a Cu pattern.

[0057] The second glass-ceramic structure can be fabricated, for example, by the following method. The preparation of green sheet A and green sheet B can be carried out in the same manner as the preparation of the first glass-ceramic structure. The internal electrodes, via conductors, and external electrodes are formed on a portion of green sheet A using a conductive paste containing Ag or Cu. A laminated green sheet is fabricated by stacking green sheet A and placing green sheet B on the surface of the laminate. The laminated green sheet is then fired to react green sheet A and green sheet B, causing crystals to form on the entire or a part of the laminated surface of green sheet B. As a result, a glass ceramic structure as shown in Figure 4 is obtained.

[0058] The firing of the laminated green sheet is carried out at a temperature of 1000°C or lower, similar to the fabrication of the first glass-ceramic structure. The firing atmosphere for the laminated green sheet is not particularly limited, but an air atmosphere is preferred when using materials that are difficult to oxidize, such as Ag, as internal electrodes, and a low-oxygen atmosphere such as a nitrogen atmosphere is preferred when using materials that are easily oxidized, such as Cu. Furthermore, the firing atmosphere for the laminated green sheet may also be a reducing atmosphere.

[0059] The second glass-ceramic structure, having the above-described structure, is endowed with high fracture toughness at the location where the second ceramic layer is formed. By positioning the second ceramic layer near or adjacent to the internal electrode, when structural defects such as internal fracture occur in the first ceramic layer, it is possible to prevent cracks from extending to the internal electrode, thereby suppressing a decrease in reliability such as circuit short circuits and disconnections.

[0060] Next, the electronic components of the present invention will be described. The electronic component of the present invention includes the first glass-ceramic structure of the present invention and / or the second glass-ceramic structure of the present invention.

[0061] The electronic component of the present invention comprises, for example, a multilayer ceramic substrate which is an example of a first glass-ceramic structure and a second glass-ceramic structure, and a chip component mounted on the multilayer ceramic substrate. Examples of chip components include LC filters, capacitors, inductors, patch antennas, couplers, and multilayer baluns.

[0062] Figure 5 is a schematic cross-sectional view showing an example of an electronic component. As shown in Figure 5, a chip component 30 may be mounted on the glass-ceramic structure (multilayer ceramic substrate) 200 while being electrically connected to an external electrode 23. This constitutes an electronic component 300 comprising the glass-ceramic structure 200.

[0063] The electronic component 300 may be mounted on a circuit board (e.g., a motherboard) so as to be electrically connected via the external electrodes 24.

[0064] The above examples illustrate the application of the second glass-ceramic structure to a multilayer ceramic substrate. However, the first and second glass-ceramic structures may also be applied to chip components mounted on a multilayer ceramic substrate. That is, the first and second glass-ceramic structures may be applied to LC filters, capacitors, inductors, patch antennas, couplers, multilayer baluns, and the like.

[0065] The first glass-ceramic structure and the second glass-ceramic structure may be applied to materials other than multilayer ceramic substrates and chip components.

[0066] This specification discloses the following:

[0067] <1> A glass-ceramic structure comprising a first ceramic layer containing crystals, and a second ceramic layer containing crystals, wherein the crystal content differs from that of the first ceramic layer, The second ceramic layer is located between the first ceramic layers in the thickness direction, or on the surface of the glass ceramic structure. The relationship between the shortest distance in the thickness direction from the surface of the glass-ceramic structure to the second ceramic layer and the thickness of the second ceramic layer is such that (shortest distance from the surface) / (thickness of the second ceramic layer) ≤ 10. The composition of the first ceramic layer described above is SiO2: 45% by weight or more, 77.5% by weight or less; B2O3: 5% by weight or more, 20% by weight or less; Al2O3: 2.6% by weight or more, 20% by weight or less; ZnO: 2.7% by weight or more, 20% by weight or less; CuO: 0% by weight or more, 3.4% by weight or less; BaO: 0% by weight or more, 10% by weight or less. The above crystal is Al2O3, Zn 2 SiO4. At least one selected from the group consisting of ZnO, ZnAl2O4, BaAl2Si2O8, ZnTiO3, Al2TiO5, TiO2, Mg2SiO4, MgSiO3, and MgO. A glass-ceramic structure characterized in that the proportion of the cross-sectional area of ​​crystals present in the second ceramic layer to the ceramic cross-section is greater than the proportion of the cross-sectional area of ​​crystals present in the first ceramic layer to the ceramic cross-section, and the difference is between 10 area% and 75 area%.

[0068] <2> The above crystals consist of two or more types. <1> The glass-ceramic structure described above.

[0069] <3> The above-mentioned second ceramic layer has two layers, <1> or <2> The glass-ceramic structure described above.

[0070] <4> A glass ceramic structure having multiple first ceramic layers containing crystals, a second ceramic layer containing crystals and having a different crystal content from the first ceramic layers, and an internal electrode, The second ceramic layer is located between the first ceramic layers in the thickness direction, or on the surface of the glass ceramic structure. The second ceramic layer and the internal electrode are adjacent in the thickness direction, or the first ceramic layer exists between the second ceramic layer and the internal electrode in the thickness direction. The relationship between the shortest distance in the thickness direction from the internal electrode to the second ceramic layer and the thickness of the second ceramic layer is such that (shortest distance from the internal electrode) / (thickness of the second ceramic layer) ≤ 10. The composition of the first ceramic layer described above is SiO2: 45% by weight or more, 77.5% by weight or less; B2O3: 5% by weight or more, 20% by weight or less; Al2O3: 2.6% by weight or more, 20% by weight or less; ZnO: 2.7% by weight or more, 20% by weight or less; CuO: 0% by weight or more, 3.4% by weight or less; BaO: 0% by weight or more, 10% by weight or less. The above crystal is Al2O3, Zn 2 SiO 4. At least one selected from the group consisting of ZnO, ZnAl2O4, BaAl2Si2O8, ZnTiO3, Al2TiO5, TiO2, Mg2SiO4, MgSiO3, and MgO. A glass-ceramic structure characterized in that the proportion of the cross-sectional area of ​​crystals present in the second ceramic layer to the ceramic cross-section is greater than the proportion of the cross-sectional area of ​​crystals present in the first ceramic layer to the ceramic cross-section, and the difference is between 10 area% and 75 area%.

[0071] <5> The above crystals consist of two or more types. <4> The glass-ceramic structure described above.

[0072] <6> The device has two of the above-mentioned second ceramic layers, and the above-mentioned internal electrode is located between the above-mentioned second ceramic layers in the thickness direction. <4> or <5> The glass-ceramic structure described above.

[0073] <7> <1> ~ <6> An electronic component containing a glass-ceramic structure as described in any of the above. [Examples]

[0074] The following are examples that more specifically disclose the glass-ceramic structure of the present invention. However, the present invention is not limited to these examples.

[0075] (Fabrication of glass-ceramic structures) (A) Preparation of Green Sheet A A mixed powder raw material was prepared by mixing SiO2 quartz powder with a glass frit composed of B2O3 / SiO2 / Al2O3 / ZnO / CuO, and after calcination, the composition, in terms of oxides, was 74.21% by weight of SiO2, 10.76% by weight of B2O3, 6.03% by weight of Al2O3, 6.02% by weight of ZnO, 0.47% by weight of CuO, and 2.50% by weight of BaO (Composition 1 in Table 5). The prepared mixed powder raw material was mixed with a toluene / ethanol mixed solvent and a dispersant, and then mixed with PSZ balls (diameter: 5 mm) in a ball mill. A butyral-based binder solution dissolved in the toluene / ethanol mixed solvent and a plasticizer were then added and mixed further to obtain the desired slurry. The obtained slurry was formed onto a carrier film using a doctor blade and dried to obtain a green sheet A with a thickness of 20 μm after firing.

[0076] (B) Preparation of green sheets B1 to B4 A powder mixture was prepared by mixing 10% to 95% by weight of the glass frit used in Green Sheet A with 5% to 90% by weight of one of the following filler components: Al2O3 (Green Sheet B1), ZnO (Green Sheet B2), Mg2SiO4 (Green Sheet B3), or BaTiO3 (Green Sheet B4). The prepared powder mixture was mixed with PSZ balls (diameter: 5 mm) in a ball mill. A butyral-based binder solution dissolved in a toluene / ethanol mixed solvent and a plasticizer were then added and mixed further to obtain the desired slurry. The obtained slurry was formed onto a carrier film using a doctor blade and dried to obtain green sheets B1 to B4, each with a post-fire thickness of 5, 10, and 50 μm, respectively.

[0077] (C) Fabrication of glass-ceramic structures The glass-ceramic structure was fabricated using the following procedure: Fifty sheets of green sheet A, cut to 78 mm x 58 mm, were stacked, and two sheets of green sheet B1, cut to the same dimensions, were either laminated on the surface of the green sheet A stack, or laminated at a position 50 μm or 100 μm in the thickness direction from the surface of the green sheet A stack. The above laminate was subjected to hydrostatic pressing at 160 MPa to produce a compressed body. After cutting the compressed body into 35 mm x 6 mm pieces, it was fired in a reducing atmosphere at a temperature of 900°C or higher and 1000°C or lower for 60 minutes or more to obtain the desired glass-ceramic structure (hereinafter also referred to as the sample). Samples were prepared in the same manner when using green sheets B2 to B4.

[0078] (D) Cross-sectional observation of glass-ceramic structure The cross-sections of the samples prepared above were exposed using blade dicing. Energy-dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) were used to observe layered layers with different crystal content near the areas where any of the green sheets B1 to B4 were stacked. In the layers with different crystal content, crystals with varying content were observed relative to the area where green sheet A was stacked, and / or crystals that were not present in the area where green sheet A was stacked, but precipitated only in the layers with different crystal content.

[0079] In samples using Green Sheet B1, the crystal structure of Al2O3, BaAl2Si2O8, and ZnAl2O4 increased. In the sample using Green Sheet B2, ZnAl2O3, ZnO and Zn 2 SiO The number of crystals (number 4) had increased. In samples using Green Sheet B3, the crystal content of Mg2SiO4, MgSiO3, and MgO increased. In samples using Green Sheet B4, the crystals of ZnTiO3, Al2TiO5, BaAl2Si2O8, and TiO2 were increased.

[0080] For samples where the proportion of the crystalline cross-sectional area in the ceramic cross-section was 5, 10, 40, and 75 areas higher than the surrounding layer, the flexural strength was measured and evaluated. The proportion of the crystal cross-sectional area was calculated as follows: First, the sample cross-section was observed using a scanning electron microscope (SEM), and the crystalline and amorphous regions were marked with specific colors. The marked crystalline regions were extracted using image analysis software (ImageJ), and after undergoing black and white binarization, the cross-sectional areas of the crystalline and amorphous regions were determined. The proportion of the crystal cross-sectional area in the sample cross-section was determined by dividing the cross-sectional area of ​​the crystalline region by the sum of the cross-sectional areas of the crystalline and amorphous regions.

[0081] (E) Measurement of flexural strength A sample measuring 35 mm in length, 6 mm in width, and 0.6 mm in thickness was prepared using the same procedure as described above, and its flexural strength was measured. Specifically, as shown in Figure 6, the sample (glass-ceramic structure 100) was supported from below at two support points F2 and F3, and a probe Pb was lowered into the center of the sample. The pressing pressure at which fracture occurred was defined as the flexural strength. The distance between support points F1 and F2, and the distance between support points F1 and F3 were both 20 mm, and the pressing speed was 1 mm / min. The measurement was performed using an Autograph AGX-5kNX (Shimadzu Corporation). Figure 6 is a perspective view showing the method for measuring the flexural strength of the glass-ceramic structure prepared in the example. For samples where the flexural strength ratio exceeded 120% compared to a reference sample prepared by laminating and firing only Green Sheet A (with the flexural strength of the reference sample set to 100%), it was determined that Green Sheet B was effective. The results are shown in Tables 1-4. Table 1 shows the percentage increase in the cross-sectional area of ​​the crystals in the second ceramic layer compared to the first ceramic layer, the thickness of the second ceramic layer (t), the distance of the second ceramic layer from the sample surface (D1), and the ratio of the flexural strength of the sample, (D1) / (t), for a sample using green sheet B1. Similar to Table 1, Tables 2-4 show the results when using green sheets B2-B4.

[0082] [Table 1]

[0083] [Table 2]

[0084] [Table 3]

[0085] [Table 4]

[0086] As shown in Tables 1-4, samples with a crystal increase rate of 10% or more and 75% or less, and (shortest distance from the surface) / (thickness of the second ceramic layer) ≤ 10, showed an improvement in flexural strength of 20% or more compared to a reference sample without a second ceramic layer. This is thought to be because the presence of crystals, which are stronger than amorphous materials such as glass, locally imparts fracture toughness and increases strength, and the mixing of materials with different coefficients of thermal expansion disperses externally applied stress. The reason why the strength decreases as the distance from the surface of the ceramic structure increases is thought to be because the area between the stress application point and the second ceramic layer, which is not reinforced, increases.

[0087] Similarly, when Green Sheet A had one of the ceramic compositions 2-7 shown in Table 5, and when the crystal content of the second ceramic layer was between 10% and 75% of the surrounding area, an improvement in the flexural strength of the sample was confirmed.

[0088] [Table 5]

[0089] (Fabrication of ceramic structures with internal electrodes) (A) Preparation of Green Sheet A Green sheet A was obtained in the same manner as described above, except that the thickness was changed so that the thickness after firing was 5 to 50 μm.

[0090] (B) Preparation of green sheets B1 to B4 Green sheets B1 to B4 were obtained in the same manner as described above.

[0091] (C) Preparation of samples for strength verification Twenty-five layers of green sheet A, with a post-firing thickness of 20 μm, were laminated, and then green sheet B1, with post-firing thicknesses of 5 μm, 10 μm, or 50 μm, was laminated on top of that. Subsequently, green sheet A was laminated to an arbitrary thickness between 0 and 50 μm, and an internal electrode (Cu) with a post-firing thickness of 50 μm was formed on top of it. Screen printing using a screen plate was performed to form the internal electrode. Specifically, an appropriate amount of Cu paste was placed on a mask, and the mask and green sheet were brought into contact. Then the Cu paste was spread by squeegeeing, and the Cu paste was printed onto the green sheet through the opening in the mask. Furthermore, after laminating green sheet A to a thickness of 0 to 50 μm on the internal electrodes, green sheet B1 with a thickness of 5 μm, 10 μm, or 50 μm after firing was laminated, and finally, 25 layers of green sheet A with a thickness of 20 μm after firing were laminated to create a laminate. A compressed body was fabricated by hydrostatic pressing of the above laminate at 160 MPa. After cutting the compressed body into 5 mm x 5 mm pieces, it was fired in a reducing atmosphere at 900-1000°C for 60 minutes or more to obtain a ceramic structure with internal electrodes, which was used as a sample for strength verification. Similar samples for strength verification were prepared when using green sheets B2 to B4.

[0092] (D) Strength confirmation test The cross-section of the strength-verification sample prepared above was exposed using blade dicing. When D2=100, as shown in Figure 7, a Vickers hardness tester (manufactured by Matsuzawa) was used to mark the cross-section at a position approximately 20 μm in the thickness direction from the internal electrode 21 observed in the cross-section (marking point P) at 50 gf. Figure 7 is a schematic cross-sectional view for evaluating the strength of the glass-ceramic structure prepared in the example. When D2=0, as shown in Figure 8, the same marking procedure was used as for D2=100, at a position approximately 20 μm in the width direction from the internal electrode 21 observed in the cross-section (marking point P). Figure 8 is a schematic cross-sectional view for evaluating the strength of the glass-ceramic structure prepared in the example. Cracks are generated inside the ceramics by the stamping process, and these cracks were defined as fracture lines BL. When the stamping load exceeds the strength of the ceramics, the fracture line BL extends from the stamping point toward the internal electrode 21 or the second ceramic layer 12. For each sample (glass-ceramic structure 200), we observed whether or not the fracture line BL reached the internal electrode 21. Furthermore, the same experiment was conducted on a ceramic and internal electrode structure formed using only Green Sheet A, without using Green Sheets B1 to B4 (Comparative Example 19). The results are shown in Table 6.

[0093] [Table 6]

[0094] As shown in Table 6, in Comparative Example 19, which does not have a second ceramic layer, and in Comparative Examples 20-27, where (shortest distance from internal electrode) / (thickness of second ceramic layer) is 20, the fracture line reached the internal electrode. However, in Examples 61-92, where (shortest distance from internal electrode) / (thickness of second ceramic layer) ≤ 10, the fracture line did not reach the internal electrode. The ceramic structures of Examples 61-92, similar to the ceramic structures of Examples 1-60, are thought to have increased strength due to the localized presence of crystals with higher strength than amorphous materials such as glass, thereby providing localized fracture toughness, and the mixing of materials with different coefficients of thermal expansion disperses external stress. From the above, it can be concluded that even if a structural defect occurs, crack extension to the internal electrode can be prevented through heat cycle tests, etc., thereby preventing a decrease in reliability such as circuit short circuits and disconnections.

[0095] The ceramic composition of Green Sheet A used in Examples 61-92 and Comparative Examples 19-27 is composition 1 in Table 5. Even when Green Sheet A had ceramic compositions 2-7 as shown in Table 5, if the crystal content of the second ceramic layer was 10% or more and 75% or less compared to the first ceramic layer, the fracture line did not reach the internal electrode, similar to Examples 61-92. [Explanation of symbols]

[0096] 11. First ceramic layer 12. Second ceramic layer 13, 13a, 13b, 13c, 13d crystal 21 Internal electrode 22 via conductors 23, 24 External electrode 30 chip components 100, 100A, 100B, 100C, 110 First glass-ceramic structure 100a One main surface of the first glass-ceramic structure 100b Other main surface of the first glass-ceramic structure 200 Second glass-ceramic structure 300 Electronic Components t Thickness of the second ceramic layer D1 Shortest distance from the surface D2 Shortest distance from internal electrode BL broken wire F1, F2, F3 fulcrum P point Pb probe

Claims

1. A glass-ceramic structure comprising a first ceramic layer containing crystals, and a second ceramic layer containing crystals, wherein the crystal content differs from that of the first ceramic layer, The second ceramic layer is located between the first ceramic layers in the thickness direction, or is located on the surface of the glass ceramic structure. The relationship between the shortest distance in the thickness direction from the surface of the glass-ceramic structure to the second ceramic layer and the thickness of the second ceramic layer is such that (shortest distance from the surface) / (thickness of the second ceramic layer) ≤ 10. The composition of the first ceramic layer is SiO ２ : 45% by weight or more, 77.5% by weight or less, B ２ O ３ : 5% by weight or more, 20% by weight or less, Al ２ O ３ : 2.6% by weight or more, 20% by weight or less; ZnO: 2.7% by weight or more, 20% by weight or less; CuO: 0% by weight or more, 3.4% by weight or less; BaO: 0% by weight or more, 10% by weight or less. where the crystal is Al ２ O ３ , Zn2SiO4, ZnO, ZnAl ２ O ４ , BaAl ２ Si ２ O ８ , ZnTiO ３ , Al ２ TiO ５ , TiO ２ , Mg ２ SiO ４ , MgSiO ３ and at least one selected from the group consisting of MgO, A glass ceramic structure characterized in that the proportion of the cross-sectional area of ​​crystals present in the second ceramic layer to the ceramic cross-section is greater than the proportion of the cross-sectional area of ​​crystals present in the first ceramic layer to the ceramic cross-section, and the difference is between 10 area% and 75 area%.

2. The glass ceramic structure according to claim 1, wherein the aforementioned crystals are of two or more types.

3. The glass-ceramic structure according to claim 1 or 2, having two of the second ceramic layers.

4. A glass ceramic structure having a plurality of first ceramic layers containing crystals, a second ceramic layer containing crystals and having a different crystal content from the first ceramic layers, and an internal electrode, The second ceramic layer is located between the first ceramic layers in the thickness direction, or is located on the surface of the glass ceramic structure. The second ceramic layer and the internal electrode are adjacent in the thickness direction, or the first ceramic layer is located between the second ceramic layer and the internal electrode in the thickness direction. The relationship between the shortest distance in the thickness direction from the internal electrode to the second ceramic layer and the thickness of the second ceramic layer is such that (shortest distance from the internal electrode) / (thickness of the second ceramic layer) ≤ 10. The composition of the first ceramic layer is SiO ２ : 45% by weight or more, 77.5% by weight or less, B ２ O ３ : 5% by weight or more, 20% by weight or less, Al ２ O ３ : 2.6% by weight or more, 20% by weight or less; ZnO: 2.7% by weight or more, 20% by weight or less; CuO: 0% by weight or more, 3.4% by weight or less; BaO: 0% by weight or more, 10% by weight or less. The aforementioned crystal is Al ２ O ３ , Zn2SiO4, ZnO, ZnAl ２ O ４ BaAl ２ Si ２ O ８ ZnTiO ３ Al ２ TiO ５ , TiO ２ Mg ２ SiO ４ MgSiO ３ It is at least one selected from the group consisting of and MgO, A glass-ceramic structure characterized in that the proportion of the cross-sectional area of ​​crystals present in the second ceramic layer to the ceramic cross-section is greater than the proportion of the cross-sectional area of ​​crystals present in the first ceramic layer to the ceramic cross-section, and the difference is between 10 area% and 75 area%.

5. The glass ceramic structure according to claim 4, wherein the aforementioned crystals are of two or more types.

6. The glass ceramic structure according to claim 4 or 5, having two of the second ceramic layers, wherein the internal electrode is located between the second ceramic layers in the thickness direction.

7. An electronic component comprising a glass-ceramic structure according to any one of claims 1, 2, 4, and 5.

8. An electronic component comprising the glass-ceramic structure described in Claim 3.

9. An electronic component comprising the glass-ceramic structure described in Claim 6.

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