Glass ceramic structure and electronic component

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

Glass ceramic structures and electronic components

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

[0002] Low-temperature co-fired ceramic materials can be co-fired with low-melting-point metal materials that have relatively low resistivity, allowing the formation of multilayer ceramic substrates with excellent high-frequency characteristics. These materials are widely used as substrate materials for high-frequency modules in information and communication terminals.

[0003] Low-temperature sintered ceramic materials include Al ２ O ３ B for ceramic materials such as ２ O ３ -SiO ２ Glass-ceramic composite materials, which are made by mixing glass and ceramic glass materials, are commonly used, but because they contain boron, which is easily volatilized during firing, the composition of the resulting substrates is prone to variation. To solve this problem, non-glass-based low-temperature sintered ceramic materials that do not contain boron have been proposed, but ceramic sintered bodies made by sintering such low-temperature sintered ceramic materials often do not achieve the desired strength characteristics due to their low fracture toughness.

[0004] Patent Document 1 discloses a ceramic sintered body containing crystalline phases of quartz, alumina, fresnoite, sanbornite, and celsian, characterized in that the relationship between the diffraction peak intensity A of the fresnoite (201) plane and the diffraction peak intensity B of the quartz (110) plane measured by powder X-ray diffraction in a diffraction peak angle range of 2θ = 10 to 40°, is A / B ≧ 2.5.

[0005] International Publication No. 2011 / 099397

[0006] In Patent Document 1, the strength of a ceramic sintered body is increased by precipitating crystals such as fresnoite or 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 locations in the ceramic sintered body. Furthermore, because the sintered body in Patent Document 1 is characterized by its material composition, it is necessary to change the composition of the glass ceramic material in order to increase the strength.

[0007] The present invention has been made to solve the above-mentioned problems, and has an object to provide a glass ceramic structure and an electronic component to which fracture toughness is locally imparted.

[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 and having a different crystal content from the first ceramic layer, wherein the second ceramic layer is present on the surface of the glass ceramic structure or between the first ceramic layers in the thickness direction, and the relationship between the shortest distance from the surface of the glass ceramic structure to the second ceramic layer in the thickness direction and the layer thickness of the second ceramic layer is (shortest distance from the surface) / (layer thickness of the second ceramic layer)≦10, and 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 wt% or more and 20 wt% or less, ZnO: 2.7 wt% or more and 20 wt% or less, CuO: 0 wt% or more and 3.4 wt% or less, BaO: 0 wt% or more and 10 wt% or less, and the crystal is ２ O ３ , ZnSi ２ O ４ , 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 MgO, and the proportion of the cross-sectional area of ​​the crystals present in the second ceramic layer in the ceramic cross section is greater than the proportion of the cross-sectional area of ​​the crystals present in the first ceramic layer in the ceramic cross section, with the difference being 10 area % or more and 75 area % or less.

[0009] A 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 internal electrodes, wherein the second ceramic layer is present 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 to each other in the thickness direction, or the first ceramic layer is present between the second ceramic layer and the internal electrode in the thickness direction, the relationship between the shortest distance from the internal electrode to the second ceramic layer in the thickness direction and the layer thickness of the second ceramic layer is (shortest distance from the internal electrode) / (layer thickness of the second ceramic layer)≦10, and 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 wt% or more and 20 wt% or less, ZnO: 2.7 wt% or more and 20 wt% or less, CuO: 0 wt% or more and 3.4 wt% or less, BaO: 0 wt% or more and 10 wt% or less, and the crystal is ２ O ３ , ZnSi ２ O ４ , ZnO, ZnAl ２ O ４ , BaAl ２ Si ２ O ８ , ZnTiO ３ , Al ２ TiO ５ , TiO ２ , Mg ２ SiO４ , MgSiO ３ and MgO, and the proportion of the cross-sectional area of ​​the crystals present in the second ceramic layer in the ceramic cross section is greater than the proportion of the cross-sectional area of ​​the crystals present in the first ceramic layer in the ceramic cross section, with the difference being 10 area % or more and 75 area % or less.

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

[0011] According to the present invention, it is possible to provide a glass ceramic structure and an electronic component to which fracture toughness is locally imparted.

[0012] FIG. 1 is a schematic cross-sectional view showing an example of a first glass ceramic structure. FIG. 2 is a schematic cross-sectional view showing another example of the first glass ceramic structure. FIG. 3A is a schematic cross-sectional view showing an example of crystal distribution in the glass ceramic structure of FIG. 1. FIG. 3B is a schematic cross-sectional view showing another example of crystal distribution in the glass ceramic structure of FIG. 1. FIG. 3C is a schematic cross-sectional view showing another example of crystal distribution in the glass ceramic structure of FIG. 1. FIG. 4 is a schematic cross-sectional view showing an example of a second glass ceramic structure. FIG. 5 is a schematic cross-sectional view showing an example of an electronic component. FIG. 6 is a perspective view showing a method for measuring the bending strength of a glass ceramic structure prepared in an example. FIG. 7 is a schematic cross-sectional view for evaluating the strength of a glass ceramic structure prepared in an example. FIG. 8 is a schematic cross-sectional view for evaluating the strength of a glass ceramic structure prepared in an example.

[0013] The first glass-ceramic structure, the second glass-ceramic structure, and the electronic component of the present invention will be described below. Note that the present invention is not limited to the following configurations, and may be modified as appropriate within the scope of the present invention. In addition, a combination of multiple individual preferred configurations described below also constitutes the present invention.

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

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

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

[0017] The relationship between the shortest distance in the thickness direction from the surface of the first glass ceramic structure to the second ceramic layer (hereinafter sometimes referred to as "shortest distance from the surface") and the thickness of the second ceramic layer is (shortest distance from the surface) / (thickness of the second ceramic layer)≦10. By satisfying this formula, the first glass ceramic structure is endowed with high fracture toughness at the position where the second ceramic 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, a cross section (WT cross section) of the glass ceramic structure passing through the center of the length (L) direction in the width (W) direction and the stacking (T) direction is exposed by polishing. If necessary, the polished surface is subjected to an etching treatment. Then, the exposed cross section is observed using a scanning electron microscope.

[0019] A line Lc is drawn that extends in the stacking direction T of the first ceramic layer and the second ceramic layer and passes through the center of the glass ceramic structure. Next, multiple lines parallel to line Lc are drawn at equal intervals. The interval between adjacent lines may be determined to be approximately 5 to 10 times the layer thickness of the second ceramic layer to be measured. Also, the same number of lines are drawn on both sides of line Lc. In other words, an odd number of lines are drawn, including line Lc. For example, three lines are drawn, including line Lc.

[0020] Next, the shortest distance from the surface and the thickness of the second ceramic layer are measured on each line, such as line Lc. However, if the second ceramic layer is missing on each line and the first ceramic layers sandwiching the 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 on a line further away from line Lc. The average values ​​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 (the shortest distance from the surface) is 0, the second ceramic layer is present on the surface of the first glass ceramic structure (FIG. 2). FIG. 2 is a schematic cross-sectional view showing another example of a first glass ceramic structure. In FIG. 2, two second ceramic layers 12 are disposed on two main surfaces of a 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, for example, preferably 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, for example, preferably 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 ranges and may be adjusted to satisfy the above formula. Note that if the shortest distance is 0, i.e., if the second ceramic layer is present 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 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 % or more by weight, ZnO: 2.6 wt % or more and 20 wt % or less, CuO: 0 wt % or more and 3.4 wt % or less, BaO: 0 wt % or more and 10 wt % or less. The above compositions are calculated as oxides.

[0024] The second ceramic layer (also referred to as the crystalline layer) has an amorphous portion having a composition within the same range as that of the first ceramic layer, but the crystalline content is different from that of the first ceramic layer, and the second ceramic layer contains more crystals. The type of crystal whose content is different is not particularly limited, and may be crystals contained in the first ceramic layer, crystals not contained in the first ceramic layer but only in the second ceramic layer, or both.

[0025] The crystals contained in the first ceramic layer include, for example, Al ２ O ３ , ZnO, etc. Examples of the crystals contained only in the second ceramic layer include ZnSi ２ O ４ , ZnAl ２ O４ , BaAl ２ Si ２ O ８ , ZnTiO ３ , Al ２ TiO ５ , TiO ２ , Mg ２ SiO ４ , MgSiO ３ , MgO, etc.

[0026] The crystals whose contents differ between the first ceramic layer and the second ceramic layer are Al ２ O ３ , ZnSi ２ O ４ , 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 MgO. The crystals having different contents may be one type or two or more types, but preferably two or more types.

[0027] The proportion of the cross-sectional area of ​​the crystals present in the second ceramic layer relative to the ceramic cross section is greater than the proportion of the cross-sectional area of ​​the crystals present in the first ceramic layer, and the difference (hereinafter sometimes referred to as difference (d1)) is 10 area% or more and 75 area% or less. Here, the cross-sectional area of ​​the crystals is not the cross-sectional area of ​​a specific type of crystal, but the total cross-sectional area of ​​all types of crystals. Since the 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 ​​the crystal in the ceramic cross section can be calculated, for example, as follows. First, the cross section of the sample is observed using a scanning electron microscope (SEM) and an X-ray diffraction analyzer (XRD), and the crystalline and amorphous parts are marked with specific colors. The marked crystalline parts are extracted using image analysis software or image editing software (Photoshop (registered trademark), ImageJ, etc.), and after black and white binarization processing, the cross-sectional areas of the crystalline parts and the amorphous parts are determined. The cross-sectional area of ​​the crystalline parts is divided by the sum of the cross-sectional areas of the crystalline parts and the amorphous parts to calculate the proportion of the cross-sectional area of ​​the crystal in the ceramic cross section.

[0029] When the difference (d1) is 10 area % or more and 75 area % or less, the bending strength of the glass ceramic structure is improved compared to when the difference (d1) is outside the above range.

[0030] Fig. 3A is a schematic cross-sectional view showing an example of the distribution of crystals in the glass ceramic structure of Fig. 1. Fig. 3B is a schematic cross-sectional view showing another example of the distribution of crystals in the glass ceramic structure of Fig. 1. Fig. 3C is a schematic cross-sectional view showing another example of the distribution of crystals in the glass ceramic structure of Fig. 1. In the glass ceramic structure 100A of Fig. 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] 3B , of the crystals 13a and 13b present in the second ceramic layer 12, the crystals 13a are also present in the first ceramic layer 11, and more crystals are contained in the second ceramic layer 12. The crystals 13b are not present in the first ceramic layer 11, and are present only in the second ceramic layer 12. As long as the difference (d1) is within the above range, the first ceramic layer 11 may contain more crystals 13a than the second ceramic layer 12, and the second ceramic layer 12 may not contain crystals 13a.

[0032] 3C , among the crystals 13a, 13b, 13c, and 13d present in the second ceramic layer 12, the crystal 13a is also present in the first ceramic layer 11, and more crystals are contained in the second ceramic layer 12. The crystals 13b, 13c, and 13d are not present in the first ceramic layer 11, but are present only in the second ceramic layer 12. As long as the difference (d1) is within the above range, the first ceramic layer 11 may contain more crystals 13a than the second ceramic layer 12, and the second ceramic layer 12 may not contain crystals 13a.

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

[0034] The first glass-ceramic structure can be produced, for example, by the following method: (1) Production of Green Sheet A: A glass-ceramic material to be the first ceramic layer of the first glass-ceramic structure is mixed with a binder, a plasticizer, etc. to prepare ceramic slurry A. Then, the ceramic slurry A is formed on a substrate film (e.g., a polyethylene terephthalate (PET) film) and dried to produce green sheet A.

[0035] (2) Preparation of Green Sheet B The glass ceramic material used in preparing Green Sheet A and Al ２ O ３ , BaTiO ３ , ZnO and Mg ２ SiO ４A mixed raw material is prepared by mixing the raw material with at least one filler component selected from the group consisting of: The higher the proportion of the filler component in the mixed raw material, the more crystals will precipitate in the second ceramic layer, so the amount of filler component is adjusted according to the desired proportion of crystals. The mixed raw material is mixed with a binder, a plasticizer, etc. to prepare ceramic slurry B. Then, ceramic slurry B is formed on a substrate film and dried to prepare green sheet B.

[0036] (3) Preparation and firing of laminated green sheet Green sheets A are laminated and green sheet B is placed on the surface of the laminate, or green sheet B is sandwiched between green sheets A to prepare a laminated green sheet, which is then fired to react green sheets A and B and generate crystals on the entire or part of the lamination surface of green sheet B. As a result, a second ceramic layer is formed at the position of green sheet B, and a glass ceramic structure (multilayer ceramic substrate) such as that shown in FIG. 1 or FIG. 2 is obtained.

[0037] Al as a filler component ２ O ３ When using Al in the second ceramic layer, ２ O ３ , BaAl ２ Si ２ O ８ and ZnAl ２ O ４ When ZnO is used as a filler component, the amount of ZnAl crystals increases in the second ceramic layer. ２ O ３ , ZnO and ZnSi ２ O ４ The crystallization of Mg as a filler component increases. ２ SiO ４ When using Mg in the second ceramic layer, ２ SiO ４ , MgSiO ３ and MgO crystals increase. BaTiO ３ When using ZnTiO ３ , Al ２ TiO ５ , BaAl２ Si ２ O ８ and TiO ２ The number of crystals increases.

[0038] BaTiO, a filler component ３ Compounds in which Ba is replaced by other alkaline earth metals can also be used as substitutes, since they precipitate crystals with the same basic structure.

[0039] In addition to using green sheet B, it is also possible to form a pattern on green sheet A using ceramic slurry B, which is the raw material for green sheet B, and then stack the patterned green sheet A and fire the resulting laminate to produce a second ceramic layer on the surface or inside of the glass ceramic structure. Methods for forming the pattern include metal mask printing, chemical etching using chemicals, physical etching such as laser processing, inkjet printing, spray coating, etc.

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

[0041] The laminated green sheets may be fired while sandwiched between constraining green sheets. The constraining green sheets may be made of an inorganic material (e.g., Al) that is not substantially fired at the firing temperature of the glass ceramic material constituting green sheets A and B. ２ O ３ ) as a main component. Therefore, the constraining green sheets do not shrink when the laminated green sheets are fired, and act to suppress shrinkage of the laminated green sheets in the direction of their main surfaces. As a result, the dimensional accuracy of the resulting structure is improved.

[0042] The first glass-ceramic structure has the above-described structure, which imparts high fracture toughness to the location where the second ceramic layer is formed. By concentrating crystal precipitation on the surface in the thickness direction of the glass-ceramic structure or at least a portion of a location close to the surface in the thickness direction, compressive stress and tensile stress can be generated in various locations within the second ceramic layer. This distributes stress in response to localized loads, thereby increasing fracture toughness.

[0043] Next, a second glass ceramic structure will be described. 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 internal electrodes, wherein the second ceramic layers are present between the first ceramic layers in the thickness direction or on the surface of the glass ceramic structure, and the second ceramic layers and the internal electrodes are adjacent to each other in the thickness direction, or the first ceramic layers are present between the second ceramic layers and the internal electrodes in the thickness direction. In the second glass ceramic structure, the first ceramic layers are a main body.

[0044] Fig. 4 is a schematic cross-sectional view showing an example of a second glass ceramic structure. The glass ceramic structure 200 shown in Fig. 4 is formed by laminating a plurality of first ceramic layers 11 and second ceramic layers 12 (four first ceramic layers and two second ceramic layers in Fig. 4). The second ceramic layers 12 are present on the surface of the glass ceramic structure 200 in the thickness direction.

[0045] The second ceramic layer may be two layers, one layer, or three or more layers. The second glass-ceramic structure preferably has two second ceramic layers.

[0046] In the glass ceramic structure 200, internal electrodes 21 are arranged in a plurality of layers. The internal electrodes 21 are arranged between two first ceramic layers 11 adjacent to each other in the thickness direction, or between the first ceramic layer 11 and the second ceramic layer 12 adjacent to each other in the thickness direction. In Fig. 4, the second ceramic layer 12 having a layer thickness t (µm) is arranged at a position at the shortest distance D2 from the internal electrode 21 in the thickness direction, and the first ceramic layer 11 is present between the second ceramic layer 12 and the internal electrode 21. Another second ceramic layer 12 is arranged so that a portion of the second ceramic layer 12 is adjacent to the internal electrode 21 in the thickness direction.

[0047] Via conductors 22 and external electrodes 23, 24 are formed in the glass ceramic structure 200. These constitute, for example, passive elements such as capacitors and inductors, or connection wiring that provides electrical connections between elements.

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

[0049] The via conductors 22 are arranged to penetrate the first ceramic layer 11 and the second ceramic layer 12, and serve to electrically connect the internal electrode 21 to the external electrodes 23 and 24. The via conductors 22 may be arranged to electrically connect two internal electrodes 21 together.

[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 this formula, the second glass ceramic structure is endowed with high fracture toughness at the position where the second ceramic layer is formed.

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

[0052] When the shortest distance from the internal electrode to the second ceramic layer in the thickness direction (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, for example, preferably 0 μm or more and 150 μm or less, more preferably 0 μm or more and 120 μm or less. The thickness of the second ceramic layer is, for example, preferably 3 μm or more and 75 μm or less, 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 and may be adjusted to satisfy the above formula. Note that if the shortest distance is 0, i.e., if the second ceramic layer is in contact with the internal electrode, the value of (shortest distance from the internal electrode) / (layer thickness of the second ceramic layer) will always be 0 regardless of the layer 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 portion, the composition of the crystals, and the content of the crystals of the first ceramic layer and the second ceramic layer may 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 ​​the crystals present in the second ceramic layer to the ceramic cross section is greater than the proportion of the cross-sectional area of ​​the crystals present in the first ceramic layer to the ceramic cross section, and the difference (d2) is 10 area% or more and 75 area% or less. When the difference (d2) is 10 area% or more and 75 area% or less, structural defects occurring around the internal electrodes and their deterioration can be suppressed compared to when the difference (d2) is outside the above range.

[0056] The internal electrodes, via conductors, and external electrodes can be formed using a conductive paste containing Ag or Cu. In the second glass-ceramic structure, the internal electrodes, via conductors, and external electrodes are preferably mainly composed of Cu. The internal electrodes, via conductors, and external electrodes can be formed by printing using a metal mask or by transfer lamination of a Cu pattern.

[0057] The second glass ceramic structure can be produced, for example, by the following method. The production of green sheet A and green sheet B can be performed in the same manner as the production of the first glass ceramic structure. The internal electrodes, via conductors, and external electrodes are formed on some of the green sheets A using a conductive paste containing Ag or Cu. The green sheets A are stacked, and green sheet B is placed on the surface of the stack to produce a laminated green sheet, which is then fired to react green sheet A and green sheet B, generating crystals on the entire or part of the stack surface of green sheet B. As a result, a glass ceramic structure such as that shown in FIG. 4 is obtained.

[0058] The laminated green sheet is fired at 1000°C or less, similar to the preparation 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 a material that is resistant to oxidation, such as Ag, is used for the internal electrodes, and a low-oxygen atmosphere, such as a nitrogen atmosphere, is preferred when a material that is resistant to oxidation, such as Cu, is used. The firing atmosphere for the laminated green sheet may also be a reducing atmosphere.

[0059] The second glass-ceramic structure has the above-described structure, and thus has high fracture toughness at the position where the second ceramic layer is formed. By disposing the second ceramic layer near or adjacent to the internal electrode, when a structural defect such as an internal fracture occurs in the first ceramic layer, the crack can be prevented from extending to the internal electrode, and a decrease in reliability such as a short circuit or disconnection can be suppressed.

[0060] Next, the electronic component 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 includes, for example, a multilayer ceramic substrate, which is an example of the first glass ceramic structure and the second glass ceramic structure, and chip components, such as an LC filter, a capacitor, an inductor, a patch antenna, a coupler, and a multilayer balun, mounted on the multilayer ceramic substrate.

[0062] Fig. 5 is a schematic cross-sectional view showing an example of an electronic component. As shown in Fig. 5, chip components 30 may be mounted on a glass ceramic structure (multilayer ceramic substrate) 200 in a state where they are electrically connected to external electrodes 23. In this way, an electronic component 300 including the glass ceramic structure 200 is formed.

[0063] The electronic component 300 may be mounted on a mounting substrate (for example, a motherboard) so as to be electrically connected via the external electrodes 24 .

[0064] Although the above describes an example in which the second glass ceramic structure is applied to a multilayer ceramic substrate, the first glass ceramic structure and the second glass ceramic structure may also be applied to chip components mounted on a multilayer ceramic substrate, i.e., the first glass ceramic structure and the second glass ceramic structure may also be applied to LC filters, capacitors, inductors, patch antennas, couplers, multilayer baluns, etc.

[0065] The first glass ceramic structure and the second glass ceramic structure may be applied to applications other than the multilayer ceramic substrate and the chip component.

[0066] The present specification discloses the following:

[0067] <1> A glass ceramic structure having a first ceramic layer containing crystals and a second ceramic layer containing crystals and having a different crystal content from the first ceramic layer, wherein the second ceramic layer is present between the first ceramic layers in a thickness direction or is present on a surface of the glass ceramic structure, the relationship between the shortest distance from the surface of the glass ceramic structure to the second ceramic layer in the thickness direction and the layer thickness of the second ceramic layer is (shortest distance from the surface) / (layer thickness of the second ceramic layer)≦10, and 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% or more by weight and 20% or less by weight, ZnO: 2.7% or more by weight and 20% or less by weight, CuO: 0% or more by weight and 3.4% or less by weight, BaO: 0% or more by weight and 10% or less by weight, and the crystal is ２ O ３ , ZnSi ２ O ４ , 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 MgO, wherein the crystals present in the second ceramic layer have a larger cross-sectional area ratio in the ceramic cross section than the crystals present in the first ceramic layer, the difference being 10 area % or more and 75 area % or less.

[0068] <2> The glass ceramic structure according to <1>, wherein the crystals are of two or more types.

[0069] <3> The glass ceramic structure according to <1> or <2>, which has two second ceramic layers.

[0070] <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 internal electrodes, wherein the second ceramic layer is present between the first ceramic layers in a thickness direction or is present on a surface of the glass ceramic structure, the second ceramic layer and the internal electrode are adjacent to each other in the thickness direction, or the first ceramic layer is present between the second ceramic layer and the internal electrode in the thickness direction, the relationship between the shortest distance from the internal electrode to the second ceramic layer in the thickness direction and the layer thickness of the second ceramic layer is (shortest distance from the internal electrode) / (layer thickness of the second ceramic layer)≦10, and 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 % or more by weight and 20% or less by weight, ZnO: 2.7% or more by weight and 20% or less by weight, CuO: 0% or more by weight and 3.4% or less by weight, BaO: 0% or more by weight and 10% or less by weight, and the crystal is ２ O ３ , ZnSi ２ O ４ , 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 MgO, wherein a ratio of a cross-sectional area of ​​the crystals present in the second ceramic layer to a cross-section of the ceramic is greater than a ratio of a cross-sectional area of ​​the crystals present in the first ceramic layer to a cross-section of the ceramic, the difference being 10 area % or more and 75 area % or less.

[0071] <5> The glass ceramic structure according to <4>, wherein the crystals are of two or more types.

[0072] <6> The glass ceramic structure according to <4> or <5>, which has two second ceramic layers, and the internal electrode is present between the second ceramic layers in the thickness direction.

[0073] <7> An electronic component comprising the glass ceramic structure according to any one of <1> to <6>.

[0074] Examples that more specifically disclose the glass-ceramic structure of the present invention are given below, but the present invention is not limited to these examples.

[0075] (Preparation of Glass Ceramic Structure) (A) Preparation of Green Sheet A ２ O ３ / SiO ２ / Al ２ O ３ / ZnO / CuO glass frit with SiO ２ Quartz powder is mixed and fired to produce a composition of SiO2 in terms of oxide. ２ 74.21% by weight, B ２ O ３ 10.76 wt%, Al ２ O ３ A mixed powder material containing 6.03 wt% Cu, 6.02 wt% ZnO, 0.47 wt% CuO, and 2.50 wt% BaO was prepared (Composition 1 in Table 5). The prepared mixed powder material was mixed with a toluene / ethanol mixed solvent and a dispersant, mixed in a ball mill with PSZ balls (diameter: 5 mm), and then a butyral-based binder solution and a plasticizer dissolved in a toluene / ethanol mixed solvent were added and further mixed to obtain the desired slurry. The resulting slurry was cast onto a carrier film with 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 The glass frit used in the green sheet A was changed to 10% by weight or more and 95% by weight or less, and Al was used as a filler component. ２ O ３(Green sheet B1), ZnO (Green sheet B2), Mg ２ SiO ４ (Green sheet B3) or BaTiO ３ A powder mixture was prepared by mixing 5% by weight or more and 90% by weight or less of one of the following: (Green Sheet B1) (Green Sheet B2) (Green Sheet B3) (Green Sheet B4). The prepared powder mixture was mixed in a ball mill with PSZ balls (diameter: 5 mm), and then a butyral-based binder solution dissolved in a toluene / ethanol mixed solvent and a plasticizer were added and further mixed to obtain the target slurry. The obtained slurry was cast onto a carrier film with a doctor blade and dried to obtain green sheets with thicknesses of 5, 10, and 50 μm after firing for Green Sheets B1 to B4, respectively.

[0077] (C) Preparation of Glass Ceramic Structure The glass ceramic structure was prepared by the following procedure. Fifty green sheets A cut to 78 mm x 58 mm were stacked, and two green sheets B1 cut to the same dimensions were laminated on the surface of the green sheet A laminate, or at a position 50 μm or 100 μm in the thickness direction from the surface of the green sheet A laminate. The laminate was subjected to isostatic pressing at 160 MPa to prepare a pressed body. The pressed body was cut into individual pieces measuring 35 mm x 6 mm and then fired in a reducing atmosphere at 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 a sample). Samples were also prepared using green sheets B2 to B4 in the same manner.

[0078] (D) Cross-sectional observation of glass ceramic structure A cross-section of the sample prepared above was exposed using a blade dicing. Energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) were used to observe layers with different crystal contents in the vicinity of the portion where any of green sheets B1 to B4 was laminated. In the layer with different crystal content, crystals whose content was different from the portion where green sheet A was laminated were observed, and / or crystals that were not present in the portion where green sheet A was laminated and precipitated only in the layer with different crystal content were observed.

[0079] In the sample using green sheet B1, Al ２ O ３ , BaAl ２ Si ２ O ８ and ZnAl ２ O ４ In the sample using green sheet B2, the amount of ZnAl crystals increased. ２ O ３ , ZnO and ZnSi ２ O ４ In the sample using green sheet B3, the Mg crystals increased. ２ SiO ４ , MgSiO ３ In the sample using green sheet B4, the amount of ZnTiO ３ , Al ２ TiO ５ , BaAl ２ Si ２ O ８ and TiO ２ The number of crystals increased.

[0080] The flexural strength was measured and evaluated for samples in which the cross-sectional area of ​​the crystals in the ceramic cross section was 5 area%, 10 area%, 40 area%, and 75 area% larger than that of the surrounding layers. The cross-sectional area ratio of the crystals was calculated as follows. First, the cross-section of the sample 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 black-and-white binarization, the cross-sectional areas of the crystalline and amorphous regions were calculated. The cross-sectional area of ​​the crystalline region was divided by the sum of the cross-sectional areas of the crystalline and amorphous regions to calculate the cross-sectional area ratio of the crystals in the sample cross section.

[0081] (E) Measurement of flexural strength A specimen for measuring flexural strength, 35 mm in length, 6 mm in width, and 0.6 mm in thickness, was prepared in the same manner as above, and the flexural strength was measured. ２ , F ３While supporting the sample (glass ceramic structure 100) from below with a support point F, the probe Pb was lowered to the center of the sample, and the pressing pressure at which the sample broke was taken as the bending strength. １ and F ２ Distance from fulcrum F １ and F ３ The distance between the first and second ceramic layers was 20 mm, and the pressing speed was 1 mm / min. Measurements were 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 structures prepared in the examples. Green sheet B was determined to be effective for samples with a flexural strength ratio exceeding 120%, assuming the flexural strength of a reference sample prepared by laminating and firing only green sheet A as 100%. The results are shown in Tables 1 to 4. Table 1 shows the increase in the cross-sectional area of ​​the crystals in the second ceramic layer compared to the first ceramic layer, the thickness (t) of the second ceramic layer, the distance (D1) from the sample surface of the second ceramic layer, and the flexural strength ratio (D1) / (t) of the sample for the sample using green sheet B1. Similar to Table 1, Tables 2 to 4 show the results for the cases using green sheets B2 to B4.

[0082]

[0083]

[0084]

[0085]

[0086] As shown in Tables 1 to 4, samples with an increase in crystallinity of 10% or more and 75% or less by area, and where the ratio of (shortest distance from the surface) / (layer thickness of the second ceramic layer) is 10 or less, showed a 20% or greater improvement in flexural strength compared to a reference sample without a second ceramic layer. This is thought to be because the local 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 expansion coefficients distributes external stress. The reason for the decrease in strength 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 becomes larger, leaving no strengthening.

[0087] Even when green sheet A has a ceramic composition of compositions 2 to 7 shown in Table 5, when the crystal content of the second ceramic layer is 10 area % or more and 75 area % or less compared to the surrounding area, an improvement in the flexural strength of the sample was similarly confirmed.

[0088]

[0089] (Preparation of Ceramic Structure Having Internal Electrodes) (A) Preparation of Green Sheet A Green sheet A was obtained in the same manner as above, except that the thickness was changed so that the thickness after firing would be 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 above.

[0091] (C) Preparation of Strength Confirmation Samples: 25 layers of green sheet A, which would have a thickness of 20 μm after firing, were laminated on top of which was green sheet B1, which would have a thickness of 5 μm, 10 μm, or 50 μm after firing. Green sheet A was then laminated to a thickness of any desired value between 0 and 50 μm, and internal electrodes (Cu), which would have a thickness of 50 μm after firing, were formed on top of the green sheet A. The internal electrodes were formed by screen printing using a screen printing plate. Specifically, an appropriate amount of Cu paste was placed on a mask, and the mask and green sheet were brought into contact. The Cu paste was then spread by squeegeeing, and the Cu paste was printed onto the green sheet through the mask openings. Green sheet A was then laminated on top of the internal electrodes to a thickness of 0 to 50 μm, followed by green sheet B1, which would have a thickness of 5 μm, 10 μm, or 50 μm after firing. Finally, 25 layers of green sheet A, which would have a thickness of 20 μm after firing, were laminated to form a laminate. The laminate was subjected to a hydrostatic press at 160 MPa to produce a bonded body. The bonded body was cut into 5 mm x 5 mm pieces and then fired in a reducing atmosphere at 900 to 1000°C for 60 minutes or more to obtain a ceramic structure with internal electrodes, which was used as a strength confirmation sample. Strength confirmation samples were also produced in the same manner using green sheets B2 to B4.

[0092] (D) Strength Confirmation Test The cross section of the strength confirmation sample prepared above was exposed using a blade dicing. When D2 = 100, as shown in Figure 7, a Vickers hardness tester (manufactured by Matsuzawa) was used to puncture at 50 gf at a position (point P) approximately 20 μm in the thickness direction from the internal electrode 21 observed on the cross section. Figure 7 is a schematic cross-sectional view used to evaluate the strength of the glass ceramic structure prepared in the example. When D2 = 0, as shown in Figure 8, a position (point P) approximately 20 μm in the width direction from the internal electrode 21 observed on the cross section was punctured in the same way as in the case of D2 = 100. Figure 8 is a schematic cross-sectional view used to evaluate the strength of the glass ceramic structure prepared in the example. Cracks were generated inside the ceramic by puncturing, and these cracks were defined as fracture lines BL. When the stamping load exceeds the strength of the ceramic, a fracture line BL extends from the stamped portion toward the internal electrode 21 or the second ceramic layer 12. For each sample (glass ceramic structure 200), it was observed whether the fracture line BL reached the internal electrode 21. A similar experiment was also conducted on a ceramic and internal electrode structure (Comparative Example 19) formed only with green sheet A without using green sheets B1 to B4. The results are shown in Table 6.

[0093]

[0094] As shown in Table 6, in Comparative Example 19, which did not have a second ceramic layer, and Comparative Examples 20 to 27, in which the ratio (shortest distance from the internal electrode) / (layer thickness of the second ceramic layer) was 20, the fracture line reached the internal electrode. However, in Examples 61 to 92, in which the ratio (shortest distance from the internal electrode) / (layer thickness of the second ceramic layer) was ≦10, the fracture line did not reach the internal electrode. Similar to the ceramic structures of Examples 1 to 60, the ceramic structures of Examples 61 to 92 are thought to have increased strength due to the local presence of crystals that are stronger than amorphous materials such as glass, thereby imparting local fracture toughness and increasing strength, and the mixing of materials with different expansion coefficients disperses external stress. From the above, even if a structural defect occurs, cracks can be prevented from extending to the internal electrode, even through heat cycle testing, preventing a decrease in reliability such as short circuits and open circuits.

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

[0096] DESCRIPTION OF SYMBOLS 11 First ceramic layer 12 Second ceramic layer 13, 13a, 13b, 13c, 13d Crystal 21 Internal electrode 22 Via conductor 23, 24 External electrode 30 Chip component 100, 100A, 100B, 100C, 110 First glass ceramic structure 100a One main surface of first glass ceramic structure 100b Other main surface of first glass ceramic structure 200 Second glass ceramic structure 300 Electronic component t Layer thickness of second ceramic layer D1 Shortest distance from surface D2 Shortest distance from internal electrode BL Fracture line F １ , F ２ , F ３ Support point P Impact point Pb Probe

Claims

1. A glass ceramic structure having a first ceramic layer containing crystals and a second ceramic layer containing crystals and having a different crystal content from the first ceramic layer, wherein the second ceramic layer is present between the first ceramic layers in the thickness direction or on the surface of the glass ceramic structure, the relationship between the shortest distance from the surface of the glass ceramic structure to the second ceramic layer in the thickness direction and the layer thickness of the second ceramic layer is (shortest distance from the surface) / (layer thickness of the second ceramic layer)≦10, and 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 and 20% by weight or less, Al ２ O ３ % or more by weight and 20% or less by weight, ZnO: 2.7% or more by weight and 20% or less by weight, CuO: 0% or more by weight and 3.4% or less by weight, BaO: 0% or more by weight and 10% or less by weight, ２ O ３ , ZnSi ２ O ４ , ZnO, ZnAl ２ O ４ , BaAl ２ S ２ O ８ , ZnTiO ３ , Al ２ TiO ５ , TiO ２ , Mg ２ SiO ４ , MgSiO ３ and MgO, wherein a ratio of a cross-sectional area of ​​the crystals present in the second ceramic layer to a cross-section of the ceramics is greater than a ratio of a cross-sectional area of ​​the crystals present in the first ceramic layer to a cross-section of the ceramics, the difference being 10 area % or more and 75 area % or less.

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

3. The glass ceramic structure according to claim 1 or 2, comprising two of said 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, wherein the second ceramic layer is present between the first ceramic layers in the thickness direction or is present on the surface of the glass ceramic structure, the second ceramic layer and the internal electrode are adjacent to each other in the thickness direction, or the first ceramic layer is present between the second ceramic layer and the internal electrode in the thickness direction, the relationship between the shortest distance from the internal electrode to the second ceramic layer in the thickness direction and the layer thickness of the second ceramic layer is (shortest distance from the internal electrode) / (layer thickness of the second ceramic layer)≦10, and 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 and 20% by weight or less, Al ２ O ３ % or more by weight and 20% or less by weight, ZnO: 2.7% or more by weight and 20% or less by weight, CuO: 0% or more by weight and 3.4% or less by weight, BaO: 0% or more by weight and 10% or less by weight, ２ O ３ , ZnSi ２ O ４ , ZnO, ZnAl ２ O ４ , BaAl ２ S ２ O ８ , ZnTiO ３ , Al ２ TiO ５ , TiO ２ , Mg ２ SiO ４ , MgSiO ３ and MgO, wherein a ratio of a cross-sectional area of ​​the crystals present in the second ceramic layer to a cross-section of the ceramics is greater than a ratio of a cross-sectional area of ​​the crystals present in the first ceramic layer to a cross-section of the ceramics, the difference being 10 area % or more and 75 area % or less.

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

6. The glass ceramic structure according to claim 4 or 5, comprising two second ceramic layers, and the internal electrode is present between the second ceramic layers in the thickness direction.

7. An electronic component comprising the glass ceramic structure according to any one of claims 1 to 6.

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