JP5382514B2 - Photosensitive paste and electronic component - Google Patents

Description

  The present invention relates to a photosensitive paste and an electronic component, and more particularly, a photosensitive paste suitable for forming an insulating layer of an electronic component such as a laminated coil component, and a ceramic multilayer substrate and a coil formed using the photosensitive paste. The present invention relates to electronic parts such as parts.

  With the increase in the density and high-speed signals of high-frequency electronic devices, electronic components incorporated in these electronic devices are required to have a manufacturing technique that can be finely processed with a thick film and has good dimensional accuracy.

  In particular, in laminated coil parts, etc., an insulating layer and a conductive pattern are stacked and the conductive patterns are electrically connected to each other through via holes. Therefore, with the miniaturization of the coil, the through holes for forming the via holes are also highly accurate. Fine processing is required.

  For this reason, in this type of electronic component, conventionally, an insulating layer is widely formed using a photosensitive paste suitable for fine processing.

  And in patent document 1, it is the photosensitive paste which contains an inorganic component and a photosensitive organic component at least, Comprising: The silica type | system | group whose content rate of the low softening point glass powder and a silica component is 80-95 mol% as an inorganic component A photosensitive paste containing composite oxide particles and having a silica composite oxide particle ratio of 15 to 40% by volume in the inorganic component has been proposed.

  Patent Document 1 discloses a filler having a core-shell structure in which silica-based composite oxide particles contain titania or zirconia, the core portion is composed of a silica component, and the shell portion is composed of titania or zirconia.

  Moreover, when forming an insulating layer using a photosensitive paste, the photosensitive paste which has a glass material as a main component which can ensure favorable insulation and can be baked at low temperature is widely used. And in order to ensure the mechanical strength of the insulating layer after sintering, it is necessary to improve glass strength.

  Non-Patent Document 1 introduces a pre-stress method as a method for improving the strength of a ceramic with a glass phase.

  In this pre-stress method, crystal particles such as quartz having a thermal expansion coefficient larger than that of a glass material (hereinafter referred to as “glass matrix”) as a base material are dispersed and mixed in the glass matrix and compressed into the glass matrix. By applying the stress, the strength of the glass is improved.

  That is, according to Non-Patent Document 1, since the glass matrix and crystal particles such as quartz have different coefficients of thermal expansion, the degree of shrinkage differs in the cooling process after firing, and the crystal particles having a large coefficient of thermal expansion have a tensile stress. And a compressive stress is generated in the glass matrix having a small coefficient of thermal expansion. And the compressive stress which arose in the glass matrix turns into prestress, and can improve the intensity | strength of glass.

JP 2007-183565 (paragraph numbers [0011], [0014], [0086])

Ceramic Editorial Committee Lecture Subcommittee, “Mechanical Properties of Ceramics”, Ceramic Association of Japan, Technical Hall Co., Ltd., issued on May 1, 1979, p. 25-47

  However, Patent Document 1 discloses a filler having a core-shell structure as described above, but the filler has a small coefficient of thermal expansion because the content of the core portion in the filler is as large as 85 to 95 mol%. The stress generated in the core portion becomes dominant and sufficient glass strength cannot be obtained. That is, the thermal expansion coefficient of the silica serving as the core part is usually smaller than the thermal expansion coefficient of the glass matrix, but since the content of the core part in the filler is as large as 85 to 95 mol%, The generated stress is dominant, compressive stress is generated, and tensile stress is generated in the glass matrix having a large thermal expansion coefficient. Therefore, the glass strength cannot be improved.

  On the other hand, in the pre-stress method described in Non-Patent Document 1, when the particle size of crystal particles such as quartz added to the glass matrix is small, the crystal particles are melted in the glass matrix, which is sufficient for the crystal particles. Tensile stress cannot be generated. For this reason, the glass matrix cannot obtain a sufficient compressive stress, and it is difficult to obtain a desired high glass strength. On the other hand, when the crystal grain size is large, it is possible to increase the tensile stress, but the amount of the glass matrix is reduced where the crystal particles are present, so the bond strength is weakened and the glass strength is reduced. Cause a decline.

  In addition, even when the volume content of the crystal particles is increased, the tensile stress of the crystal particles is increased, and thus the compressive stress of the glass matrix is also increased, but when a material having a large dielectric constant such as zirconia is used for the crystal particles, There is a possibility that the electrical characteristics may fluctuate, and the degree of freedom in material selection becomes narrow. Furthermore, if the volume content of the crystal particles is increased, the volume content of the glass matrix is decreased, so that the sinterability is deteriorated and the strength may be decreased.

  In the method of Non-Patent Document 1, since the thermal expansion coefficient is a substance-specific value, the combination of both the glass matrix and the crystal particles determines the compressive stress generated in the glass matrix, thereby improving the glass strength. There are also limitations. In addition, when crystal particles having a particle size larger than the film thickness of the glass layer after sintering are added to the glass matrix, the smoothness of the glass layer after sintering may be impaired. In addition, in this case, cracks may occur at the interface between the protruding crystal particles and the glass matrix, leading to a decrease in strength.

  The present invention has been made in view of such circumstances, and provides a photosensitive paste having a high glass strength and a high degree of freedom in selecting a filler material, and an electronic component such as a coil component using the photosensitive paste. The purpose is to do.

  The present inventor conducted intensive research to achieve the above object, and the core material is a ceramic filler having a core-shell structure in which the shell portion is formed of a material having a smaller thermal expansion coefficient than the core portion and the glass matrix. The glass strength is high and the filler material can be freely selected by making it contained in the glass material, and by setting the volume content of the ceramic filler, the average particle diameter, and the volume content of the core part in the ceramic filler within a predetermined range. The knowledge that a high-sensitivity photosensitive paste can be obtained was obtained.

  The present invention has been made based on such knowledge, and the photosensitive paste according to the present invention has a core part and a core shell having a shell part made of a material having a larger thermal expansion coefficient than the core part. The ceramic filler of the mold is contained in a glass matrix having a smaller coefficient of thermal expansion than the shell part, and the volume content of the ceramic filler is 1 to 30% by volume, and the core part in the ceramic filler The volume content is 0.1 to 70% by volume, and the average particle size of the ceramic filler is 15 nm to 5000 nm.

In the photosensitive paste of the present invention, the difference (α1-α2) between the thermal expansion coefficient α1 of the shell portion and the thermal expansion coefficient α2 of the core portion exceeds 1 × 10 ⁻⁶ / ° C. It is also preferable that

  Further, in the photosensitive paste of the present invention, the core portion contains at least one selected from quartz glass, aluminum titanate, and cordierite, and the shell portion includes magnesia, zirconia, alumina, and It is also preferable that at least one selected from titania is contained.

  The electronic component according to the present invention is an electronic component obtained by firing a component body in which insulating layers and conductive layers are alternately stacked, and the insulating layer uses any of the photosensitive pastes described above. It is characterized by being formed.

  According to the photosensitive paste, a core-shell type ceramic filler having a core part and a shell part made of a material having a larger thermal expansion coefficient than the core part has a thermal expansion coefficient higher than that of the shell part. While contained in a small glass matrix, the volume content of the ceramic filler is 1 to 30% by volume, and the volume content of the core part in the ceramic filler is 0.1 to 70% by volume, In addition, since the ceramic filler has an average particle size of 15 nm to 5000 nm, due to the difference in shrinkage behavior between the core and the shell, a compressive stress is generated in the core having a small coefficient of thermal expansion, and the shell having a large coefficient of thermal expansion. Tensile stress is generated in. Further, between the shell portion and the glass matrix, tensile stress is generated in the shell portion having a large thermal expansion coefficient, and compressive stress is generated in the glass matrix having a small thermal expansion coefficient. The tensile stress on the shell side that occurs near the interface between the shell and the glass matrix increases due to the tensile stress generated between the shell and the core. As a result, the compressive stress generated in the glass matrix also increases. As a result, the glass strength can be improved.

  In addition, the core-shell structure ceramic filler increases the compressive stress of the glass matrix compared to the case where a ceramic filler made of a single material is added to the glass matrix. It is possible to obtain a large glass strength.

  In addition, the ceramic filler may have a small average particle size, and therefore, the ceramic filler does not protrude from the sintered glass layer, the strength variation is small, and the photosensitive paste that does not impair the smoothness of the glass layer is obtained. Can be obtained. Furthermore, since the ceramic filler has a core-shell structure, the tensile stress on the shell part side at the interface between the shell part and the glass matrix is increased, so that the glass strength is improved only by adding a small amount of the ceramic filler. It is possible to increase the degree of freedom in selecting the ceramic filler material.

  According to the electronic component of the present invention, in the electronic component obtained by firing a component body in which insulating layers and conductive layers are alternately stacked, the insulating layer includes the photosensitive paste according to any one of the above. Since it is formed by use, it is possible to obtain various electronic components such as a coil component and a ceramic multilayer substrate having high strength and small strength variation.

  Specifically, an electronic component having a bending strength of 200 MPa or more and small strength variation between products can be obtained with high efficiency.

It is the top view which showed typically one Embodiment of the photosensitive paste which concerns on this invention. 1 is a perspective view of a laminated coil component as one embodiment (large embodiment) of an electronic component according to the present invention. It is a principal part disassembled perspective view of FIG.

  Next, an embodiment of the present invention will be described in detail.

  FIG. 1 is a plan view schematically showing a photosensitive paste according to the present invention, and the photosensitive paste contains a ceramic filler 2 in a glass matrix 1.

  The ceramic filler 2 has a core-shell structure including a core portion 3 and a shell portion 4 that covers the core portion 3.

  Specifically, the shell part 4 is formed of a material whose thermal expansion coefficient α1 is larger than the thermal expansion coefficient α2 of the core part 3 and the thermal expansion coefficient α3 of the glass matrix 1.

  As described above, the ceramic filler 2 has a core-shell structure, and a material having a thermal expansion coefficient α1 of the shell portion 4 larger than the thermal expansion coefficient α2 of the core portion 3 allows the thermal expansion coefficient α2 to be reduced in the cooling process after firing. A compressive stress is generated in the small core portion 3 as shown by an arrow x, and a tensile stress is generated in the shell portion 4 having a large thermal expansion coefficient α1 as shown in the arrow y direction. Moreover, between the shell part 4 and the glass matrix 1, as shown by the arrow u, a tensile stress arises in the shell part 4 with a large thermal expansion coefficient (alpha) 1, and the glass matrix 1 with a small thermal expansion coefficient (alpha) 3 shows with the arrow v. Thus, compressive stress is generated. And the shell part 4 becomes large in the tensile stress at the interface between the shell part 4 and the glass matrix 1 due to the tensile stress generated between the core part 3, and as a result, the compressive stress generated in the glass matrix 1 is also reduced. growing. That is, between the ceramic filler 2 and the glass matrix 1, in addition to the stress caused by the difference in thermal expansion coefficient (α1-α3) between the shell portion 4 and the glass matrix 1, between the core portion 3 and the shell portion 4. The stress caused by the difference in thermal expansion coefficient (α1−α2) is applied. And thereby, the glass strength of the glass matrix 1 increases, and the strength of the glass layer after sintering can be improved.

  Table 1 exemplifies materials of the core part 3 and the shell part 4 constituting the ceramic filler 2, and the core-shell type ceramic filler of the present invention can be formed by appropriately selecting these materials.

  According to Table 1, for example, when aluminum titanate is used as the core material, alumina, zirconia, cristobalite or the like having a larger thermal expansion coefficient than aluminum titanate can be used as the shell material.

  As described above, the core material and the shell material can be selected as necessary, and the degree of freedom of material selection is remarkably wide.

If there is a difference in the behavior of heat shrinkage between the shell portion 4 and the core portion 3, the difference in thermal expansion coefficient (α1-α2) is not particularly limited, but is sufficient for the shell portion 4. In order to produce a high tensile strength, it is preferable that the difference in thermal expansion coefficient (α1-α2) exceeds 1 × 10 ⁻⁶ / ° C. From such a viewpoint, it is preferable to use quartz glass, aluminum titanate, and cordierite as the core portion 3, and it is preferable to use magnesia, zirconia, alumina, and titania as the shell portion 4.

  In the photosensitive paste of the present invention, the volume content of the ceramic filler 2 is 1 to 30% by volume, the volume content of the core part 3 in the ceramic filler 2 is 0.1 to 70% by volume, The average particle size is 15 nm to 5000 nm.

  The reason will be described below.

(1) Volume content rate of ceramic filler 2 By making the photosensitive paste contain the ceramic filler 2, the glass strength can be improved. However, when the volume content of the ceramic filler 2 is less than 1% by volume, the effect of adding the ceramic filler 2 cannot be exhibited, and it is difficult to improve the glass strength. On the other hand, when the volume content of the ceramic filler 2 exceeds 30% by volume, the volume content of the ceramic filler 2 is increased and the skeleton structure of the glass matrix 1 is weakened, which may cause a decrease in glass strength.

  Therefore, in the present embodiment, the blending amounts of the ceramic filler 2 and the glass matrix 1 are adjusted so that the volume content of the ceramic filler 2 is 1 to 30% by volume.

(2) Volume content of the core part 3 in the ceramic filler 2 As described above, the ceramic filler 2 has a core-shell structure, and the thermal expansion coefficient α1 of the shell part 4 is larger than the thermal expansion coefficient α2 of the core part 3. The glass strength can be improved by selecting the material. However, when the volume content of the core portion 3 in the ceramic filler 2 is less than 0.1% by volume, the volume content of the core portion 3 is small, so that the ceramic filler 2 is substantially the same as a single material. Only the glass strength can be obtained. On the other hand, when the volume content of the core part 3 in the ceramic filler 2 exceeds 70% by volume, the volume content of the core part 3 becomes excessive, and sufficient tensile stress cannot be generated in the shell part 4. Since the stress of the core part 3 acts directly on the glass matrix 1, the glass strength cannot be improved. In particular, when the thermal expansion coefficient α3 of the glass matrix 1 is larger than the thermal expansion coefficient α2 of the core portion 3, tensile stress is generated in the glass matrix 1, and there is a possibility that the glass strength is lowered.

  Therefore, in the present embodiment, the blending amounts of the core part 3 and the shell part 4 are adjusted so that the volume content of the core part 3 in the ceramic filler 2 is 0.1 to 70% by volume.

(3) Average particle diameter of ceramic filler 2 In the present invention, the thermal expansion coefficients α1 and α2 of the core portion 3 and the shell portion 4, the volume content of the ceramic filler 2, and the volume content of the core portion 3 in the ceramic filler 2 In addition, the average particle diameter D of the ceramic filler 2 obtained by adding the diameter d of the core portion 3 and the thickness t of the shell portion 4 is also important. That is, when the average particle diameter D of the ceramic filler 2 is less than 15 nm, the average particle diameter D becomes too small, and the ceramic filler 2 melts and diffuses during firing, making it impossible to obtain a desired high strength glass. On the other hand, when the average particle diameter D of the ceramic filler 2 exceeds 5000 nm, the interface between the glass matrix 1 and the ceramic filler 2 may be cracked or the smoothness of the glass layer may be impaired, and the strength variation also increases.

  Therefore, in the present embodiment, the average particle size of the ceramic filler 2 is used so that the average particle size is 15 nm to 5000 nm.

  Next, the manufacturing method of the said photosensitive paste is demonstrated.

  First, the ceramic filler 2 is produced.

  For example, a core material having a predetermined particle diameter for forming the core portion 3 and a shell material for forming the shell portion 4 are prepared.

  Then, an alkoxide solution of the shell material is prepared, and the core material is added to the alkoxide solution, thereby forming an amorphous shell material layer on the surface of the core material.

  Next, the amorphous shell material layer is fired at a predetermined temperature (for example, 400 to 600 ° C.) to be crystallized, thereby producing a ceramic filler 2 in which the core portion 3 has a volume content of 0.1 to 70% by volume. To do.

  Next, a glass paste having a predetermined composition containing a glass matrix, a photosensitive varnish, a photopolymerization initiator, a solvent, and a sintering aid is prepared.

  Here, the glass matrix is not particularly limited. For example, a B-Si-Li-Al glass material, a B-Si-Li-Ba glass material, and a B-Si-Pb-Al glass material are used. Various glass materials such as Si-BK glass materials can be used.

  The photosensitive varnish and the photopolymerization initiator are not particularly limited, and as the photosensitive varnish, for example, photosensitive polyimide, photosensitive epoxy, and the like can be used. As the photopolymerization initiator, benzyl , Benzoin ethyl ether, benzoylbenzoic acid and the like can be used.

  The solvent is not particularly limited, and ethanol, acetone, xylene and the like can be appropriately used.

  Furthermore, as a sintering aid, a glass material containing Si, such as a Si—B—Ca—Li—Zn-based glass material, can be used.

  Moreover, it is also preferable to contain a thixotropic agent, a dispersing agent, etc. as needed.

  And the ceramic filler 2 is added to the said glass paste so that a volume content rate may become 1-30 volume%, and it kneads | mixes, making it disperse | distribute with a three roll mill, and, thereby, the photosensitive paste is produced.

  As described above, the photosensitive paste of the present invention includes a core-shell ceramic filler 2 having a core portion 3 and a shell portion 4 formed of a material having a larger thermal expansion coefficient than the core portion 3. 4 is contained in the glass matrix 1 having a smaller thermal expansion coefficient than 4, the volume content of the ceramic filler 2 is 1 to 30% by volume, and the volume content of the core portion 3 in the ceramic filler 2 is 0. Since the average particle diameter of the ceramic filler 2 is 15 nm to 5000 nm, the tensile stress on the shell side generated near the interface between the shell part 4 and the glass matrix 1 is 4 due to the tensile stress generated between the core portion 3 and the core portion 3, and as a result, the compressive stress generated in the glass matrix also increases, thereby improving the glass strength. It is possible to achieve.

  And since the compressive stress of the glass matrix 1 increases compared with the case where the ceramic filler 2 which consists of a single material in this way is added to the glass matrix 1, only a small amount of the ceramic filler 2 is added, compared with the past. It becomes possible to obtain a large glass strength.

  In addition, since the ceramic filler 2 may have a small average particle size, the ceramic filler 2 does not protrude from the sintered glass layer, has little variation in strength, and does not impair the smoothness of the glass layer. Can be obtained. Further, since the ceramic filler 2 has a core-shell structure, the tensile stress on the shell portion 4 side at the interface between the shell portion 4 and the glass matrix 1 is increased, so only by adding a small amount of the ceramic filler 2, The glass strength can be improved, and the degree of freedom in selecting the material of the ceramic filler 2 can be expanded.

  FIG. 2 is a perspective view showing an embodiment of a laminated coil component as an electronic component using the photosensitive paste.

  That is, in this laminated coil component, external electrodes 6 a and 6 b are formed on both ends of the component body 5.

  FIG. 3 is an exploded perspective view of the component body 5.

  That is, the component body 5 has an insulating substrate 7, and insulating layers 8 a to 8 d formed using the photosensitive paste are sequentially stacked on the insulating substrate 7. In addition, coiled conductor patterns 9a to 9d are formed on the surfaces of the insulating substrate 7 and the insulator layers 8a to 8c, and the conductor patterns 9a to 9d are electrically connected to each other through via holes 10a to 10c. Yes. One end portions of the conductor pattern 9a and the conductor pattern 9d form lead conductors 11a and 11b, and the conductor patterns 9a to 9d are connected to the external electrodes 6a and 6b via the lead conductors 11a and 11b.

  Next, a method for manufacturing the coil component will be described.

  First, for example, a conductive forming photosensitive paste is applied onto an insulating substrate 7 made of alumina or the like by using a screen printing method, a spin coating method, a doctor blade method, or the like to form a conductive film.

  Here, the conductive forming photosensitive paste is not particularly limited, and in the photosensitive paste of the present invention, a conductive powder such as Ag or Cu is used instead of the glass material to be a glass matrix. Can be used containing the same compositional components.

  Next, after the conductor film is dried, it is exposed through a photomask having a predetermined pattern.

  Next, after performing development processing and further removing unnecessary portions of the conductor film, for example, firing treatment is performed in air under predetermined conditions, thereby forming a coiled conductor pattern 9a having a lead conductor 11a.

  Next, the insulating layer forming photosensitive paste of the present invention is applied using a screen printing method, a spin coating method, a doctor blade method or the like so as to cover the conductor pattern 9a on the insulating substrate 7, and an insulating film is formed. Form.

  Next, after the insulating film is dried, the insulating film is exposed and developed through a photomask having a predetermined pattern, and unnecessary portions are removed. An insulating layer 8a having the following is formed.

  Next, the conductive forming photosensitive paste is filled into the through-holes, and the conductive forming photosensitive paste is applied onto the insulating layer 8a, and exposed and developed in the same manner as described above to form the conductive pattern 9b on the insulating layer 8a. Form.

  Thereafter, the same process is repeated, and finally the insulator layer 8d is formed, and then the external electrode conductive paste is applied and baked to form the external electrodes 6a and 6b, whereby the laminated coil component is manufactured.

  As described above, since the insulating layers 8a to 8d are formed of the photosensitive paste in the laminated coil component, a coil component with high strength and small strength variation can be obtained.

  Specifically, an electronic component having a bending strength of 200 MPa or more and small strength variation between products can be obtained with high efficiency.

  The present invention is not limited to the above embodiment. For example, the above manufacturing method is merely an example, and is not limited to the above embodiment. In the above embodiment, the laminated coil component has been described as an example, but it goes without saying that the present invention can also be applied to a ceramic multilayer substrate or an LC composite component.

  Next, examples of the present invention will be specifically described.

[Production of ceramic filler]
[Examples 1 to 10]
Aluminum titanate (Al ₂ TiO ₅ ) particles having a particle size of ₅ to 2000 nm were added to the aluminum alkoxide solution to form an amorphous alumina layer having a thickness of 5 to 2000 nm on the surface of the aluminum titanate.

  Subsequently, the amorphous alumina layer was crystallized by firing at a temperature of 500 ° C., pulverized with a ball mill, mixed with water, and finely filtered to remove coarse particles. And thereby, the ceramic filler of Examples 1-10 whose particle size of a core part is 5-2000 nm, the thickness of a shell part is 4.5-1500 nm, and a filler particle size is 15-5000 nm was produced.

Example 11
Quartz glass particles having a particle size of 20 nm were added to the silicon-based alkoxide solution to form an amorphous silica layer having a thickness of 20 nm on the surface of the quartz glass.

  Next, the amorphous silica layer was crystallized by baking at a temperature of 1200 to 1500 ° C., pulverized with a ball mill, mixed with water, and finely filtered to remove coarse particles. Thus, the ceramic filler of Example 11 having a core part particle size of 20 nm, a shell part thickness of 15 nm, and a filler particle diameter of 50 nm was produced.

Example 12
Zircon particles having a particle size of 20 nm were added to the aluminum alkoxide solution to form an amorphous alumina layer having a thickness of 20 nm on the surface of zircon.

  Subsequently, the amorphous alumina layer was crystallized by firing at a temperature of 500 ° C., pulverized with a ball mill, mixed with water, and finely filtered to remove coarse particles. Thus, the ceramic filler of Example 12 having a core part particle size of 20 nm, a shell part thickness of 15 nm, and a filler particle diameter of 50 nm was produced.

[Comparative Example 1]
A glass paste containing no ceramic filler was used as Comparative Example 1.

[Comparative Examples 2 and 3]
Aluminum titanate and alumina having a particle size of 50 nm were prepared and used as ceramic fillers of Comparative Examples 2 and 3, respectively.

[Comparative Example 4]
A mixed solution was prepared by mixing a titanium alkoxide solution and an aluminum alkoxide solution. Then, alumina particles having a particle diameter of 20 nm were added to the mixed solution to form an amorphous mixed layer made of titania and alumina having a thickness of 20 nm on the surface of the alumina. The layer was crystallized, ground with a ball mill, mixed with water and microfiltered to remove coarse particles. This produced a ceramic filler of Comparative Example 4 having a core part particle size of 20 nm, a shell part thickness of 15 nm, and a filler particle diameter of 50 nm.

[Comparative Examples 5 to 10]
Ceramic fillers of Comparative Examples 5 to 10 were produced in substantially the same manner and procedure as in Example 1.

[Production of ceramic sintered body]
First, a glass paste having a thermal expansion coefficient of 5-6 × 10 ⁻⁶ / ° C. having the component composition shown in Table 2 was prepared.

  Next, the ceramic fillers of the above examples and comparative examples are added to the glass paste so that the volume content is 0 to 50% by volume, and dispersed and kneaded by a three-roll mill. Examples 1 to 12 and Comparative Example 1 10 photosensitive pastes were prepared.

  Subsequently, this photosensitive paste was screen-printed on a film made of polyethylene terephthalate (PET), and then the process of drying → exposure → development → printing →... Was repeated to produce a green sheet having a thickness of 15 μm.

  Next, this green sheet was fired at a temperature of 850 ° C., and samples of Examples 1 to 12 and Comparative Examples 1 to 10 were produced.

  Table 3 shows the thermal expansion coefficient, component composition, filler particle size, filler content of each ceramic filler of Examples 1-12, and Table 4 shows the thermal expansion coefficient, component composition of each ceramic filler of Comparative Examples 1-10. The filler particle size and filler content are shown.

(Sample evaluation)
About each 20 samples of each said Example and a comparative example, the autograph (made by Shimadzu Corp.) was used, the three-point bending test was done based on JISR-1601, and the maximum load was measured. And average bending strength was calculated | required from sample size and the maximum load, and also the standard deviation (sigma) of bending strength was calculated | required.

  Table 5 shows the measurement results. In the table, the average bending strength indicates an average value in 20 samples.

  Since the comparative example 1 is only a glass paste and does not contain a ceramic filler, it was confirmed that the average bending strength was as low as 150 MPa.

  In Comparative Examples 2 and 3, since the ceramic filler is formed only of the core portion, when fired, the compressive stress of the core portion directly acts on the glass matrix, and therefore only a low glass strength of less than 200 MPa can be obtained. It was. In particular, Comparative Example 2 using aluminum titanate in the core portion uses a core material having a coefficient of thermal expansion smaller than that of the glass matrix, so that tensile strength is imparted to the glass matrix, and thus the average bending strength is 80 MPa. And fell extremely.

  In Comparative Example 4, alumina is used for the core part and aluminum titanate is used for the shell part. Since the thermal expansion coefficient of the shell part is smaller than the thermal expansion coefficient of the core part, tensile stress acts on the core part. As a result, compressive stress acted on the shell portion. As a result, tensile strength was imparted to the glass matrix, and the average bending strength was extremely reduced to 60 MPa.

  In Comparative Example 5, the average bending strength was as low as 180 MPa. This is because the volume content of the core part in the ceramic filler is as low as 0.05% by volume and sufficient compressive stress cannot be obtained, so the tensile stress in the shell part is also small, and therefore sufficient compressive stress is applied to the glass matrix. This is probably because the grant was not possible.

  In Comparative Example 6, the volume content of the core portion in the ceramic filler is excessive, such as 80% by volume, and the volume content of the shell portion is small, so that sufficient tensile strength does not occur in the shell portion. The average bending strength was as low as 170 MPa.

  In Comparative Example 7, since the volume content of the ceramic filler in the sample is as low as 0.5% by volume, the effect of adding the ceramic filler 2 cannot be exhibited. Therefore, the average bending strength is as low as 155 MPa, and the standard The deviation σ was 45, and the variation in bending strength also increased.

  In Comparative Example 8, since the volume content of the ceramic filler in the sample was excessive at 50% by volume, the skeleton structure of the glass matrix became weak and the average bending strength was as low as 140 MPa.

  In Comparative Example 9, since the average particle size of the ceramic filler was too small as 10 nm, the ceramic filler was melted and diffused, and the average bending strength was as low as 180 MPa.

  In Comparative Example 10, since the average particle size of the ceramic filler was too large as 7000 nm, the average bending strength was as low as 170 MPa, the standard deviation σ was 45, and the variation in bending strength was also large.

  In contrast, in Examples 1 to 12, the shell part is formed of a material having a larger thermal expansion coefficient than the core part or the glass matrix, and the volume content of the ceramic filler is in the range of 1 to 30% by volume, Since the volume content of the core in the ceramic filler is in the range of 0.1 to 70% by volume, and the average particle size of the ceramic filler is in the range of 15 nm to 5000 nm, the average bending strength is 200 to 330 MPa. It was found that the strength variation was suppressed and the standard deviation σ was 30 or less. In particular, Examples 1-5, 7, 9, 11 and 12 having a ceramic filler volume content of 15-30% by volume and a ceramic filler average particle size of 50-500 nm have an average bending strength of 250 MPa even when fired. As described above, it was found that a photosensitive paste having a standard deviation σ of 20 or less, high strength, and small strength variation can be obtained.

  In addition, when the samples of Examples 1 to 10 were sandwiched between electrodes, the capacitance was measured, and the dielectric constant was measured from the measured capacitance and the thickness of the glass layer, the average value of the dielectric constant was 6. It was found that the increase in dielectric constant can be suppressed.

  Even when the insulating layer is formed using a photosensitive paste, various electronic components such as a laminated coil component and a ceramic multilayer substrate having good mechanical strength can be obtained.

1 Glass matrix (glass material)
2 Ceramic filler 3 Core part 4 Shell part

Claims (4)

A core-shell type ceramic filler having a core part and a shell part made of a material having a larger thermal expansion coefficient than the core part is contained in a glass material having a smaller thermal expansion coefficient than the shell part. With
The volume content of the ceramic filler is 1 to 30% by volume,
The volume content of the core part in the ceramic filler is 0.1 to 70% by volume,
And the photosensitive paste characterized by the average particle diameter of the said ceramic filler being 15 nm-5000 nm. The photosensitive paste according to claim 1, wherein a difference (α1-α2) between a thermal expansion coefficient α1 of the shell portion and a thermal expansion coefficient α2 of the core portion exceeds 1 × 10 ^-6 / K. . The core portion contains at least one selected from quartz glass, aluminum titanate, and cordierite,
3. The photosensitive paste according to claim 1, wherein the shell portion contains at least one selected from magnesia, zirconia, alumina, and titania. In an electronic component formed by firing a component body in which insulating layers and conductive layers are alternately laminated,
An electronic component, wherein the insulating layer is formed using the photosensitive paste according to any one of claims 1 to 3.

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