JP4407291B2 - Ceramic multilayer substrate - Google Patents

Description

  The present invention relates to a ceramic multilayer substrate, and more particularly to a ceramic multilayer substrate having a highly reliable internal structure and no defects.

  As this type of conventional ceramic multilayer substrate, for example, a multilayer composite ceramic substrate described in Patent Document 1 and a composite multilayer ceramic component described in Patent Document 2 are known.

  A multilayer composite ceramic substrate described in Patent Document 1 is a laminate in which a plurality of insulator sheets on which via holes, conductive patterns and resistance patterns are formed and a dielectric sheet on which via holes and conductive patterns are formed are laminated. In the multilayer composite ceramic substrate in which the capacitor, resistor, and wiring pattern are built in the fired body in which the multilayer body is fired, and electrically connected to the electrode pattern of the capacitor and formed on the outer surface of the fired body Insulation formed by baking the insulator sheet with an overcoat layer made of glass or a composite ceramic containing glass so as to cover at least a part of all the inner layer wiring patterns electrically connected to the via holes It is formed on the body layer. When manufacturing this multilayer composite ceramic substrate, a dielectric sheet smaller than the insulator sheet is sandwiched in the insulator sheet, and a capacitor or the like is embedded in the insulator sheet.

  In addition, the composite multilayer ceramic component described in Patent Document 2 includes a lead-based perovskite high dielectric material and aluminum oxide in an amount of 40 to 60 wt%, lead oxide in an amount of 1 to 40 wt%, silicon oxide in an amount of 2 to 40 wt%, and boron oxide in an amount of 1 to 40 wt%. Glass having a composition such that 30 wt%, Group II element oxide 0.05 to 25 wt%, Group IV element oxide (except silicon and lead) 0.01 to 10 wt%, and a total of 100 wt% A laminated sintered body in which an insulator mainly composed of ceramic and a conductor are integrally laminated and fired, and includes at least one wiring conductor layer, the high dielectric constant material, and a conductor formed therein. And a capacitor element. When manufacturing this composite multilayer ceramic component, a high dielectric constant material is made into a paste, this is printed on an insulator green sheet by screen printing, and this sheet is laminated to form a capacitor element at an arbitrary position. Yes.

  By the way, like the ceramic multilayer substrate described in each of the above patent documents, a functional material layer 2 such as a high dielectric constant material having a function different from that of the base material layer 1 such as an insulator is partially formed inside the base material layer. When the functional material layer 2 is formed in a predetermined shape, the planar shape of the functional material layer 2 is generally formed into a quadrangle as shown in FIG. 10A, for example, and the shape of the end 2A is generally a straight line. It is.

  However, when a functional material layer is partially built in as in the conventional ceramic multilayer substrate described above, a laminated body is formed by laminating a base material layer such as an insulator sheet and a functional material layer, and pressing them. After that, the multilayer body is fired to produce a ceramic multilayer substrate. At the time of pressure bonding, the periphery 2A of the functional material layer 2 swells as shown by a one-dot chain line in FIG. May not have the desired pattern. Further, at the time of firing, warpage due to shrinkage difference (difference in firing shrinkage rate) between the functional material layer 2 and the base material layer 1 is likely to cause substrate deformation such as waviness and delamination. In particular, delamination is a functional material. There existed a subject that it was easy to generate | occur | produce in the edge part 2A of the layer 2. FIG.

JP-A-1-117392 Japanese Patent Publication No. 2-053951

  The present invention has been made in order to solve the above-described problems, and has an object to provide a ceramic multilayer substrate having a built-in functional material layer with high pattern accuracy, free from internal structural defects due to substrate deformation, delamination, and the like. Yes.

  As a result of various investigations on substrate deformation and internal structural defects due to the shrinkage difference between the functional material layer and the base material layer during firing, the present inventors have found that these phenomena are caused by shrinkage between the base material layer and the functional material layer. It was found that the stress caused by the difference was caused by concentration at the boundary between them. Therefore, the present inventor suppresses internal structural defects such as delamination by applying a specific treatment to the end of the functional material layer, and further prevents pattern deformation of the functional material layer due to pressure bonding. I found out that I can do it.

The present invention has been made on the basis of the above knowledge, and the ceramic multilayer substrate according to claim 1 of the present invention includes a base layer formed by laminating a plurality of base ceramic layers, and the base layer. A dielectric ceramic layer having a predetermined shape made of a different material and disposed between the base ceramic layers, and first and second electrodes sandwiching the dielectric ceramic layer, the dielectric ceramic layer comprising: In a state viewed from above, the dielectric ceramic layer is formed with irregularities over its entire length at the end portion reaching the base ceramic layer .

According to a second aspect of the present invention, there is provided the ceramic multilayer substrate according to the first aspect, wherein the dielectric ceramic layer has a wedge shape in which an end portion is thinner toward an outer side. .

  The ceramic multilayer substrate according to claim 3 of the present invention is characterized in that, in the invention according to claim 1 or 2, the average value of the depth of the irregularities is set to 10 to 500 μm. Is.

According to a fourth aspect of the present invention, in the ceramic multilayer substrate according to any one of the first to third aspects , at least one of the first and second electrodes is provided. The area of the electrode is smaller than the area of the dielectric ceramic layer and set to a size that does not reach the concave and convex portions .

Moreover, the ceramic multilayer substrate according to claim 5 of the present invention is the invention according to any one of claims 1 to 4, wherein a conductor is provided on the base material layer, and the conductor is made of Ag or It is characterized by being formed of a conductive metal mainly composed of Cu .

Thus, the base ceramic layer constituting the ceramic multilayer substrate of the present invention is not particularly limited as long as it is formed of a ceramic material, but considering that a low-resistance metal is used as an internal conductor or the like, The base ceramic layer is preferably formed of a low-temperature sintered ceramic material, for example. The low-temperature sintered ceramic material refers to a ceramic material that can be co-fired with a low melting point metal such as Ag, Au, Cu, Ni, Ag / Pd, Ag / Pt at a temperature of 1000 ° C. or lower. Examples of the low-temperature sintered ceramic material include a glass composite material obtained by mixing borosilicate glass with ceramic powder such as alumina, forsterite, and cordierite, and a crystallized glass of ZnO-MgO-Al ₂ O ₃ -SiO ₂ Crystallized glass based material using non-glass based material such as BaO—Al ₂ O ₃ —SiO ₂ based ceramic powder or Al ₂ O ₃ —CaO—SiO ₂ —MgO—B ₂ O ₃ based ceramic powder Can be mentioned.

The functional material layer constituting the ceramic multilayer substrate of the present invention is not particularly limited as long as it is formed of a material having a function (material characteristics such as physical characteristics) different from that of the base ceramic layer. The functional material layer can be formed of, for example, a dielectric material, a resistor material, a magnetic material, or an insulator material. When a capacitor is formed in the base material layer, a dielectric ceramic material is used for the functional material layer. Then, in forming a capacitor on the substrate layer, in the case of forming a substrate ceramic layer using a BaO-Al ₂ O ₃ -SiO ₂ based ceramic powder as a low-temperature co-fired ceramic material as a dielectric ceramic material For example, JP 2000-21967, JP 2000-226255, JP 2000-226256, JP 2000-264722, JP 2000-264723, and JP 2000-264724. It is preferable to use a dielectric ceramic material described in JP-A No. 2000-281436.

The dielectric ceramic material described in Japanese Patent Application Laid-Open No. 2000-2111967 includes 89.0 to 91.5 mol% BaTiO ₃ , 8.0 to 10.5 mol% BaSnO ₃ , Pb (Sn _1/3 Bi _{2). / 3} ) Dielectric ceramic components each containing 0.5 to 2.0 mol% of O ₃ , 10.0 to 55.0 mol% of barium oxide, 1.0 to 50.0 mol% of It is a dielectric ceramic composition formed by mixing 5.0 to 35.0% by weight of a glass component composed of silicon oxide and 30.0 to 60.0 mol% boron oxide.

Dielectric ceramic material described in JP 2000-226255 Laid is represented by _{[(Ba 1-x-y Ca} x Sr y) O ] _{m · (Ti 1-z Zr} z) O 2, m, x , Y, and z are in a relationship of 1.005 ≦ m ≦ 1.03, 0.02 ≦ x ≦ 0.22, 0.05 ≦ y ≦ 0.35, and 0.00 <z ≦ 0.20, respectively. The filled dielectric ceramic component comprises 20.0-60.0 mol% barium oxide, 10.0-55.0 mol% silicon oxide, and 10.0-40.0 mol% boron oxide. It is a dielectric ceramic composition formed by mixing 3.0 to 35.0% by weight of a glass component.

JP dielectric ceramic material according to 2000-226256 JP, 2.5 to 17.5 mol% of BaO, 50.0 to 75.0 mol% of _TiO 2, 15.0-47.5 mol% Of NdO _3/2 , 2.0-20.0 wt% PbTiO ₃ with respect to the main composition, 10.0-65.0 mol% BaO, 1.0-50 A dielectric ceramic composition comprising 3.0 to 30.0% by weight of a glass component obtained by mixing 0.0 mol% of SiO ₂ and 10.0 to 60.0 mol% of B ₂ O ₃ .

The dielectric ceramic material described in JP-A-2000-264722 has bismuth oxide as a main component represented by xBaO-yTiO ₂ -zMe (where x + y + z = 1, Me is an oxide of a lanthanoid element). 3 to 17 wt% and lead oxide 0.5 to 10 wt%, respectively, and a dielectric component obtained by mixing a glass component having the same composition as the glass component contained in the low-temperature sintered ceramic material. It is a body ceramic composition.

  The dielectric ceramic material described in JP 2000-264723 A is 32.0 to 46.0% by weight of strontium titanate, 28.0 to 46.0% by weight of lead titanate, and 8. 8% of calcium titanate. 10 to 16.0% by weight, bismuth oxide 5.0 to 16.0% by weight, titanium oxide 3.0 to 10.0% by weight, and a dielectric ceramic component containing 10% barium oxide. Dielectric ceramic formed by mixing glass components obtained by mixing 0.0 to 65.0 mol%, 1.0 to 55.0 mol% of silicon oxide, and 10.0 to 75.0 mol% of boron oxide. It is a composition.

  The dielectric ceramic material described in JP 2000-264724 A is 85.0 to 90.0 wt% of barium titanate, 8.5 to 12.0 wt% of calcium zirconate, and 0.005 of magnesium titanate. Dielectric ceramics containing 5 wt% or less, cerium oxide 0.5 wt% or less, bismuth oxide 0.1 to 1.0 wt%, and tin oxide 0.1 to 1.0 wt%, respectively. A glass component obtained by mixing 10.0 to 65.0 mol% of barium oxide, 1.0 to 55.0 mol% of silicon oxide, and 10.0 to 75.0 mol% of boron oxide with the components. It is a dielectric ceramic composition formed by mixing.

The dielectric ceramic material described in Japanese Patent Laid-Open No. 2000-281436 is BaO—TiO ₂ — (Nd _1-m Me _m ) O _3/2 (where Me represents a lanthanoid element, and 0 ≦ m ≦ 1. 20.0-65.0 mol% barium oxide, 5.0-50.0 mol% silicon oxide, 10.0-50.0 mol% It is a dielectric ceramic composition formed by mixing 3.0 to 35.0% by weight of a glass component made of boron oxide.

The functional material layer is provided with irregularities over the entire length of the end portion located in the base material layer in a state in which the functional material layer is viewed in plan . The unevenness may be any form as long as each side of the functional material layer is longer than a straight line by repeatedly forming the convex part and the concave part to exhibit various forms such as a wave shape and a jagged shape. The total length of the end portion located in the base material layer is, of course, the function when the entire functional material layer is located in the base material layer and the entire periphery of the end portion is included in the base material layer. This means that a part of the end portion of the conductive material layer is exposed on the end surface of the base material layer. Thus, by providing unevenness over the entire length of the end of the functional material layer located in the base material layer, there is a shrinkage difference between the functional material layer and the base ceramic layer during firing, so that the functional material Even if stress is concentrated on the edge of the layer, this stress can be dispersed in individual irregularities over the entire length of the edge to suppress and prevent delamination from the base ceramic layer at the edge of the functional material layer. it can. Furthermore, since the deformation of the functional material layer due to the crimping is absorbed as the deformation of the unevenness at the end, the deformation of the functional material layer can be remarkably suppressed as compared with the linear end, and the function is extended. The pattern accuracy of the conductive material layer can be greatly improved.

  The average depth of the irregularities is preferably set in the range of 10 to 500 μm, and more preferably in the range of 30 to 300 μm. If the depth of the unevenness is less than 10 μm, the effect of the unevenness may not be exhibited, and if it exceeds 500 μm, the unevenness is too large, and the unevenness may interfere with internal conductors such as via-hole conductors and line conductors provided in the base ceramic layer. This is not desirable.

  The thickness of the functional material layer is preferably formed in the range of 5 to 100 μm, and more preferably in the range of 7 to 50 μm. If the thickness of the functional material layer is less than 5 μm, the deformation due to the shrinkage of the functional material layer is small, so there is no influence by the shrinkage difference with the base ceramic layer, and if it exceeds 100 μm, delamination may not be suppressed, which is preferable. Absent. However, when a capacitor is formed using a dielectric ceramic material as the functional material layer, a larger capacity can be obtained with a thinner thickness.

  The ceramic multilayer substrate of the present invention may be provided with a conductor pattern such as an inner conductor or an outer conductor, but these conductor patterns have a low melting point that can be co-fired with the low-temperature sintered ceramic material. It can be formed of a metal containing a metal as a main component. As the low melting point metal, for example, the above-described Ag and Cu are preferably used.

  When the conductor pattern is formed as the first and second capacitor electrodes, one of the first and second capacitor electrodes has an area smaller than that of the dielectric ceramic layer constituting the capacitor. However, it is preferable that the unevenness at the end is not reached. If the area of both capacitor electrodes is larger than the area of the dielectric ceramic layer, a desired capacitance value cannot be obtained as a capacitor, which is not preferable. In other words, a desired capacitance value can be set by the capacitor electrode having an area smaller than that of the dielectric ceramic layer.

According to the onset bright, no internal structural defects due to delamination or the like from ceramic layers of the ends of the substrate deformation and dielectric ceramic layer due to heat shrinkage difference between the ceramic layer and the dielectric ceramic layers during firing, the pattern accuracy A ceramic multilayer substrate incorporating a high dielectric ceramic layer can be provided.

  Hereinafter, the present invention will be described based on the embodiment shown in FIGS. In each figure, FIG. 1 is a cross-sectional view showing an embodiment of the ceramic multilayer substrate of the present invention, FIG. 2 is a view showing a main part of FIG. 1, (a) is a plan view thereof, (b) is ( FIG. 3 is a cross-sectional view of a), FIG. 3 to FIG. 7 are diagrams showing a manufacturing process of the ceramic multilayer substrate shown in FIG. 1, FIG. 8 is a diagram showing another embodiment of the ceramic multilayer substrate of the present invention, and FIG. It is a top view which shows the carrier film and dielectric material green sheet layer in the case of producing several ceramic multilayer substrates simultaneously.

  For example, as shown in FIG. 1, the ceramic multilayer substrate 10 of the present embodiment has a base layer 11 formed by laminating a plurality of base ceramic layers 11 </ b> A, and has a function different from that of the base layer 11. Functional material layer 12 disposed between the ceramic layers 11A, an internal line conductor 13 formed in a predetermined pattern on an appropriate base ceramic layer 11A, and via holes connecting the upper and lower internal line conductors 13 and 13 And a conductor 14. A first outer conductor 15 is formed in a predetermined pattern on the upper surface of the base material layer 11, and a mounting component 16 such as a chip-type ceramic capacitor or a semiconductor device is connected to the outer conductor 15 via solder (not shown). . A second outer conductor 17 is formed on the lower surface of the base material layer 11, and the ceramic multilayer substrate 10 is mounted on a printed wiring board (not shown) via the outer conductor 17.

  The functional material layer 12 is entirely incorporated in the base material layer 11 and sealed in the base material layer 11. In the present embodiment, the functional material layer 12 is formed of a dielectric ceramic material and is configured as a dielectric ceramic layer of a capacitor. Therefore, hereinafter, the functional material layer 12 will be described as the dielectric ceramic layer 12. As shown in FIG. 1, first and second capacitor electrodes 18 and 19 are formed on the upper and lower surfaces of the dielectric ceramic layer 12.

  FIG. 2 shows the dielectric ceramic layer 12 and the first and second capacitor electrodes 18 and 19 shown in FIG. For example, as shown in FIG. 2A, the dielectric ceramic layer 12 has a recess 12 </ b> A continuously formed over the entire length of the end, and has a concavo-convex shape over the entire length of the end of the dielectric ceramic layer 12. Presents. The average value of the depth of the recess 12A (the depth of the unevenness) is formed in the range of 10 to 500 μm for the reason described above. Moreover, the dielectric ceramic layer 12 is formed in the range of 5-100 micrometers thickness from the reason mentioned above.

  The ceramic multilayer substrate 10 of this embodiment can be produced by firing the raw laminate 20 shown in FIG. The raw laminate 20 includes all the components except for the mounting component 16 of the ceramic multilayer substrate 10. That is, the raw laminate 20 includes a base ceramic green sheet 21A corresponding to the base ceramic layer 11A, a base green sheet layer 21 corresponding to the base layer 11, and a dielectric green sheet corresponding to the dielectric ceramic layer 12. Layer 22, conductive paste layer (internal line conductor layer) 23 corresponding to internal line conductor 13, conductive paste layer (via hole layer) 24 corresponding to via hole conductor 14, first and second external conductors 15, 17 Conductive paste layers (first and second electrodes) corresponding to the conductive paste layers (first and second outer conductor layers) 25 and 27 and the first and second capacitor electrodes 18 and 19, respectively. Layer) 28, 29. The base ceramic green sheet 21A and the dielectric green sheet layer 22 can be formed by the above-described compositions. Each conductive paste layer can be formed of a conductive paste containing the low melting point metal described above as a main component. And the unevenness | corrugation 22B (refer FIG. 5) is formed in the edge part whole periphery of the dielectric material green sheet layer 22. FIG. A method of forming the unevenness 22B will be described later.

  By providing the unevenness 22B over the entire length of the end of the dielectric green sheet layer 22 as described above, the dielectric green which is the boundary with the base ceramic green sheet 21A when the dielectric green sheet layer 22 contracts by firing. Even if the stress is concentrated on the end of the sheet layer 22, this stress can be dispersed in the irregularities 22B of the dielectric green sheet layer 22 to suppress shrinkage deformation around the entire periphery of the end of the sheet layer 22. It prevents delamination between the body ceramic layer 12 and the base ceramic layer 11A, and suppresses warpage from the base ceramic layer 11A around the end of the dielectric ceramic layer 12, that is, delamination and deformation of the substrate. Alternatively, it can be prevented.

  The entire circumference of the end portion of the dielectric ceramic layer 12 is formed in a wedge shape that becomes thinner toward the outside. Since the end portion of the entire circumference is formed in a wedge shape, the influence on other elements, undulation, and the like can be suppressed. Also, a first capacitor electrode 18 having an area smaller than that area is formed on the upper surface of the dielectric ceramic layer 12, and the capacitor electrode 18 does not reach the recess 12 </ b> A on the outer peripheral edge of the dielectric ceramic layer 12. It is formed in size. A desired capacitance value of the capacitor can be obtained by the first capacitor electrode 18.

  Further, when the end of the dielectric green sheet layer 22 swells when the green laminate 20 is formed by pressure bonding, the bulge is dispersed into individual irregularities, so that deformation of the outer peripheral end can be suppressed. As shown in FIG. 2B, there is no possibility that the adjacent via-hole conductor 14 or the internal line conductor 13 is deformed and damaged (disconnected).

  Next, the manufacturing method of the ceramic multilayer substrate 10 of this embodiment is demonstrated, referring FIGS. In order to obtain the ceramic multilayer substrate 10, first, a raw laminate 20 as shown in FIG. 3 is manufactured through the following steps.

  First, a base ceramic slurry is prepared by adding and mixing a binder, a plasticizer, and an organic solvent to a ceramic powder made of a low-temperature sintered ceramic material containing, for example, silicon oxide, alumina, barium oxide, and the like. This base ceramic slurry is applied onto a carrier film (not shown) made of, for example, polyethylene terephthalate by using a doctor blade method to form a predetermined number of base ceramic green sheets 21A.

  Next, the internal line conductor layer 23 is screen-printed on each of the base ceramic green sheets 21A, if necessary, by screen-printing a conductive paste containing a conductive powder mainly composed of Ag or Cu and an organic vehicle. The first and second outer conductor layers 25 and 27 and the first electrode layer 28 are formed and dried. Further, through holes are provided in a predetermined pattern in each base ceramic green sheet 21A, and a via hole layer 24 is formed by filling each through hole with a conductive paste for via hole conductors. Note that at least one of the first and second outer conductor layers 25 and 27 may be formed after obtaining the raw laminate 20.

  In this embodiment, the dielectric ceramic material includes, for example, a dielectric ceramic material obtained by adding glass powder, a binder, a plasticizer, and an organic solvent to a dielectric ceramic powder mainly composed of barium titanate and mixing them. Prepare paste. Then, as shown in FIG. 4A, a dielectric ceramic green sheet 22A is formed on a carrier film 30 made of polyethylene terephthalate using a paste containing a dielectric ceramic material, for example, using a doctor blade method. A portion of the dielectric ceramic green sheet 22A becomes the dielectric ceramic layer 12 after firing.

  Next, as shown in FIG. 4B, the second electrode layer 29 is formed on the dielectric ceramic green sheet 22A by screen printing a conductive paste. Further, as shown in FIG. 4C, the dielectric ceramic green sheet 22A on the carrier film 30 is irradiated with laser light L using a carbon dioxide laser oscillator so as to penetrate only the dielectric ceramic green sheet 22A. By controlling the laser output, as shown in FIG. 5A, a continuous hole is formed along the shape of the dielectric ceramic layer 12 to separate the dielectric green sheet layer 22 from the dielectric ceramic green sheet 22A and to perform dielectric. Concavities and convexities 22 </ b> B are formed on the entire periphery of the end of the body green sheet layer 22. At this time, irregularities of an arbitrary size can be formed by adjusting the processing hole diameter and the hole pitch.

  Thereafter, portions of the dielectric ceramic green sheet 22A shown in FIG. 4 (c) other than the dielectric green sheet layer 22 are removed from the carrier film 30, and FIG. 4 (d) and FIG. The dielectric green sheet layer 22 is left as shown in FIG. At this time, the dielectric green sheet layer 22 is positioned at a predetermined position on the carrier film 30. In this embodiment, a circular hole is continuously formed in the dielectric ceramic green sheet 22A to form the concave portion 22B. However, the concave portion 22B may be formed in another arbitrary shape such as a square as necessary. Can do.

  In the present embodiment, it is preferable that the laser light L is not penetrated through the carrier film 30, but it is actually difficult to control the laser output so as to cut only the dielectric green sheet layer 22. Therefore, as shown in FIG. 6, a hole 30 </ b> A is often formed in the carrier film 30. 6, (a) is a partial cross-sectional view showing the main part of FIG. 4, (b) is a plan view from above showing the main part of FIG. 4, and (c) is the main part of FIG. It is a top view from the lower part which shows a part.

  Even if the hole 30A is formed in the carrier film 30 as shown in FIG. 6, as shown in FIG. 6 (c), the hole 30A is only distributed intermittently in the carrier film 30. In other words, the portion of the dielectric green sheet 22 is not cut off from the carrier film 30. Therefore, the dielectric green sheet layer 22 can be held at a predetermined position by the carrier film 30.

  When the holes 30A are formed in the carrier film 30 by irradiation with the laser light 17, the carrier green sheet 22 is not cut off from the carrier film 30 and the carrier film 30 can be handled easily thereafter. The film 30 preferably has a thickness of 5 μm or more. If the thickness of the carrier film 30 is less than 5 μm, the strength is insufficient and handling as the carrier film 30 is difficult, and the carrier film 30 may be cut by forming the holes 30A. If the strength of the carrier film 30 is insufficient, the film is easily deformed, and the dielectric green sheet layer 22 may not be held on the carrier film 30 with high positional accuracy. Therefore, the thickness of the carrier film 30 is preferably about 20 to 250 μm from the viewpoint of securing the film strength.

  The thickness of the dielectric green sheet layer 22 is preferably such that the dielectric ceramic layer 12 having a thickness of 5 to 100 μm can be formed after firing. With this thickness, the laser output can be controlled without cutting the carrier film 30. As the laser, for example, a He—Ne laser, an excimer laser, a YAG laser, or the like can be used in addition to the carbon dioxide laser.

  Laser processing in this embodiment can perform spot-like processing, has high processing accuracy, does not complicate the process, and can be processed at low cost. However, in addition to laser processing, for example, photolithography technology or photo etching technology can also be used, and punching processing can also be used in a half cut manner using a punching blade. When only the dielectric green sheet layer 22 is left on the carrier film 30, the portion other than the dielectric green sheet layer 22 may be irradiated with laser light to remove the portion.

Next, the dielectric green sheet layer 22 formed on the carrier film 30 is transferred onto a predetermined base ceramic green sheet 21A. In this case, as shown in FIG. 7A, a mold 40 having an opening having a dimension substantially equal to the outer dimension of the carrier film 30 is used. First, the base ceramic green sheet 21A is accommodated in the mold 40, and then the carrier film 30 is laminated on the base ceramic green sheet 21A with the dielectric green sheet layer 22 facing downward. 10 to 2000 kg / cm ²
The carrier film 30 is pressure-bonded onto the base ceramic green sheet 21A. Next, the carrier film 30 is peeled from the pressure-bonded body, and the dielectric green sheet layer 22 and the second electrode layer 29 are transferred to the base ceramic green sheet 21A and integrated.

  At this time, the dielectric green sheet layer 22 is preliminarily positioned on the carrier film 30, and the dielectric green sheet layer 22 and the base ceramic green sheet 21A are positioned based on the outer shape of the carrier film 30. Therefore, the dielectric green sheet layer 22 can be accurately transferred to a predetermined position of the base ceramic green sheet 21A.

Next, as shown in FIG. 7 (b), the base on which the first electrode layer 28 is formed on the base ceramic green sheet 21A to which the dielectric green sheet layer 22 and the second electrode layer 29 are transferred. The material ceramic green sheet 21A is laminated and pressure-bonded in the mold 20 with the first electrode layer 28 facing downward. Subsequently, a predetermined number of base ceramic green sheets 21A are repeatedly laminated, and finally crimped with a pressure of 100 to 2000 kg / cm ² to obtain a raw laminate 20.

  Thereafter, the raw laminate 20 is fired to obtain the multilayer ceramic substrate 10. At this time, when the base ceramic green sheet 21A includes a low-temperature sintered ceramic material and the dielectric green sheet layer 22 includes glass powder, the raw laminate 20 is fired at a temperature of 800 to 1000 ° C., for example. . Further, when the inner line conductor layer 23, the via hole layer 24, the first and second outer conductor layers 25 and 27, and the first and second electrode layers 28 and 29 contain Ag or Cu as a main component, they are reducible. Baking in an atmosphere prevents oxidation of these metals.

  For positioning between the base ceramic green sheet 21A and the dielectric green sheet layer 22 and between the base ceramic green sheets 21A, positioning marks (for example, holes or (Printed figure) may be formed in advance, and the transfer and stacking operations may be performed while recognizing the position of the mark with a camera.

  As described above, according to the present embodiment, since the irregularities 12B are provided over the entire length of the end portion located in the base material layer 11 in the dielectric ceramic layer 12, internal structural defects such as substrate deformation and delamination are provided. Thus, the ceramic multilayer substrate 10 incorporating the dielectric ceramic layer 12 with high pattern accuracy can be obtained. Moreover, since the average value of the depth of this unevenness | corrugation 12B was set to 10-500 micrometers, the internal structure defect of the ceramic multilayer substrate 10 can be prevented more reliably. Further, since the internal line conductor 13 and the like are formed of a conductive metal mainly composed of Ag or Cu, the resistance value of the internal line conductor 13 or the like can be reduced. Further, a capacitor can be formed in the ceramic multilayer substrate 10 by the dielectric ceramic layer 12. Furthermore, since the first capacitor electrode 18 is set to an area smaller than that of the dielectric ceramic layer 12, a desired capacitance value can be obtained with certainty.

  FIG. 8 shows another embodiment of the present invention. Also in this embodiment, the same reference numerals are given to the same or corresponding parts as in the above embodiment, and the present invention will be described. In the present embodiment, the functional material layer (for example, a dielectric ceramic layer) 12 is formed thicker than in the above embodiment. Since the dielectric ceramic layer 12 is partially interposed between the base ceramic layers 11A, if the dielectric ceramic layer 12 is thick, the flatness of the base layer 11 is impaired, and a ceramic multilayer substrate having a uniform thickness is obtained. There is a risk of not being able to. The thickness of the dielectric green sheet layer 22 is preferably within, for example, 300 μm. However, when the thickness is exceeded, the flatness of the base ceramic green sheet 21A is impaired in the raw laminate 20 due to the thickness. Therefore, as shown in FIG. 8, a step-adjusting ceramic green sheet 21B for adjusting a step due to the dielectric ceramic layer 12 is interposed, and the flatness of the base ceramic green sheet 21A is improved by the step-adjusting ceramic green sheet 21B. I try to keep it. The step-adjusting ceramic green sheet 21B is formed of the same material as the base ceramic green sheet 21A.

  The ceramic multilayer substrate 10 of the present embodiment can be manufactured in the same procedure as in the above embodiment except that the step-adjusting ceramic green sheet 21B is interposed. Therefore, features of the present embodiment will be described with reference to FIG.

  For example, as shown in FIG. 8 (a), a step-adjustment ceramic green sheet 21B having an opening 21C previously opened by punching or lasering a region corresponding to the dielectric green sheet layer 22 is prepared. When the step-adjusting ceramic green sheet 21B is laminated on the base ceramic green sheet 21A, the dielectric green sheet layer 22 fills the opening 21C of the step-adjusting ceramic green sheet 21B and the upper surface of the step-adjusting ceramic green sheet 21B is flat. become. The step-adjusting green sheet 21B has a via hole layer 23A corresponding to the via hole layer 23 of the base ceramic green sheet 21A. Thereafter, the multilayer ceramic substrate 10 shown in FIG. 8B can be obtained by performing the same process as in the above embodiment. In FIG. 8B, reference numeral 11B denotes a step-adjusting ceramic layer. Also in this embodiment, the same effect as the said embodiment can be expected.

  Any of the step of transferring the dielectric green sheet layer 22 onto the base ceramic green sheet 21A and the step of stacking the step-adjusting green layer 21B onto the base ceramic green sheet 21A may be performed first. .

  In each of the above-described embodiments, the steps for producing one ceramic multilayer substrate 10 have been illustrated, but usually a plurality of ceramic multilayer substrates 10 are produced simultaneously as shown in FIG. That is, as shown in FIG. 9, a plurality of dielectric green sheet layers 22 are formed in a matrix on a carrier film 30 to obtain a raw laminate in a mother state, and then divided along a dividing line indicated by a one-dot chain line. By doing so, a raw laminate 20 for each multilayer ceramic substrate 10 can be produced.

  Note that the present invention is not limited to the above embodiments. In each of the above embodiments, the dielectric ceramic layer 12 is not provided with a via-hole conductor. However, when it is necessary to provide a via-hole conductor in the functional material layer, a through-hole for the via-hole conductor is formed before and after laser processing. It may be provided and the through hole may be filled with a conductive paste. The point is that the present invention includes any irregularities formed over the entire length of the end portion of the functional material layer of the ceramic multilayer substrate.

  The present invention can be suitably used for a ceramic multilayer substrate incorporating elements such as a capacitor, an inductor, and a resistor.

It is sectional drawing which shows one Embodiment of the ceramic multilayer substrate of this invention. It is a figure which shows the principal part of the ceramic multilayer substrate shown in FIG. 1, (a) is the top view, (b) is the sectional drawing. It is sectional drawing which shows the raw laminated body for manufacturing the ceramic multilayer substrate shown in FIG. (A)-(d) is a figure which shows the process of forming the dielectric material ceramic green sheet part shown in FIG. 2, respectively. (A) is a top view which shows the state which cut | disconnected the dielectric ceramic green sheet part from the dielectric ceramic green sheet on a carrier film, and formed the recessed part, (b) is the state which removed the unnecessary part of the dielectric ceramic green sheet FIG. FIGS. 5A and 5B are diagrams showing states of the dielectric ceramic green sheet portion and the carrier film when the laser beam is irradiated in the step shown in FIG. 4C, where FIG. 5A is a sectional view thereof, and FIG. 5B is a dielectric ceramic green sheet. The top view from a part side, (c) is a top view from the carrier film side. (A) is sectional drawing which shows the process of transcribe | transferring a dielectric material ceramic green sheet part on a base-material ceramic green sheet, (b) laminates | stacks another base-material ceramic green sheet on the base-material ceramic green sheet after transcription | transfer. It is sectional drawing which shows the state which carried out. It is a figure which shows the manufacturing process of a ceramic multilayer substrate when a dielectric ceramic layer is thick, (a) is sectional drawing which shows the process of laminating | stacking the green sheet for level | step adjustments on a dielectric ceramic green sheet part, (b) is (a) It is sectional drawing which shows the ceramic multilayer substrate produced through the process of (). It is a top view which shows the carrier film in which the dielectric ceramic green sheet part used for producing a raw laminated body in a mother state was formed. (A) is a top view which shows the base-material ceramic green sheet and dielectric ceramic green sheet part which comprise the conventional ceramic multilayer substrate, (b) is the dielectric ceramic green when the raw laminated body is crimped | bonded and baked It is a top view which shows typically a deformation | transformation of a sheet | seat part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ceramic multilayer substrate 11 Base material layer 11A Base material ceramic layer 12 Dielectric ceramic layer (functional material layer)
12A Concavity and convexity 13 Internal conductor (conductor)
14 Via-hole conductor (conductor)
15, 17 Outer conductor 18, 19 Capacitor electrode

Claims (5)

A base layer formed by laminating a plurality of base ceramic layers, a dielectric ceramic layer having a predetermined shape made of a material different from the base layer and disposed between the base ceramic layers, and the dielectric A first electrode and a second electrode sandwiching the ceramic layer, and in a state in which the dielectric ceramic layer is viewed in plan, at an end portion of the dielectric ceramic layer reaching the base ceramic layer over the entire length thereof A ceramic multi-layer substrate, wherein irregularities are formed . 2. The ceramic multilayer substrate according to claim 1, wherein the end portion of the dielectric ceramic layer has a wedge shape that becomes thinner toward the outside .   3. The ceramic multilayer substrate according to claim 1, wherein an average depth of the unevenness is set to 10 to 500 μm. These types Symbol first, second electrodes, claims, characterized in that an area of at least one of the electrodes smaller than the area of the dielectric ceramic layers was set to a size which does not reach the recess of the uneven The ceramic multilayer substrate according to any one of claims 1 to 3 . The ceramic multilayer according to any one of claims 1 to 4 , wherein a conductor is provided on the base material layer, and the conductor is formed of a conductive metal mainly composed of Ag or Cu. substrate.

Images