JP2009170566A - Multilayer ceramic substrate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent form defects such as warp, distortion and waviness of an obtained multilayer ceramic substrate when manufacturing the multilayer ceramic substrate using a so-called non-contraction process. <P>SOLUTION: Of a plurality of restraining green layers 28-33 provided in a raw laminate 2 to be the multilayer ceramic substrate by being calcined, the restraining green layers 28 and 33 at the outermost position in a laminate direction exert higher restraining force than that of the restraining green layers 29-32 at intermediate positions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multilayer ceramic substrate and a method for manufacturing the same, and more particularly to an improvement for improving the accuracy of the form of the multilayer ceramic substrate manufactured using a so-called non-shrink process.

  As a conventional method for producing a multilayer ceramic substrate that is of interest to the present invention, there is one described in, for example, Japanese Patent Application Laid-Open No. 2001-291955 (Patent Document 1).

  In Patent Document 1, in a method for manufacturing a multilayer ceramic substrate by a so-called non-shrink process, in particular, in a raw laminate that is fired to obtain a multilayer ceramic substrate, a green layer for a substrate containing a low-temperature sintered ceramic material, and a substrate A plurality of constraining green layers including inorganic material powders that are disposed in contact with the principal surface of a specific one of the green layers and that are not sintered at the sintering temperature of the low-temperature sintered ceramic material. When a part of the material contained in the ceramic layer for penetration penetrates into the constraining green layer, the inorganic material powder contained in the constraining green layer is in a fixed state. A method for manufacturing a multilayer ceramic substrate in which the constraining layer is left without being removed is described.

  In Patent Document 1, when the thicknesses of the plurality of substrate green layers stacked in the raw laminate are different from each other, the thicker substrate green layer tends to shrink more greatly in the firing step. For this reason, means for solving the problem that the obtained multilayer ceramic substrate may be warped, and form defects such as distortion and waviness may occur. That is, in Patent Document 1, a constraining green layer in contact with a thicker substrate green layer is thicker, and a constraining green layer in contact with a thinner substrate green layer is made thinner, so that a plurality of substrate green layers are formed. The respective shrinkage ratios are made equal to each other, thereby making it difficult to cause a defective shape of the obtained multilayer ceramic substrate.

However, in order not to cause a form defect by the above-described method, the thickness of each constraining green layer must be accurately adjusted based on the thickness of each of the plurality of base green layers. However, such adjustment is relatively difficult, and many types of green sheets to be used as constraining green layers having different thicknesses must be prepared, resulting in a problem that the process becomes complicated. become.
JP 2001-291955 A

  Accordingly, an object of the present invention is to provide a method for manufacturing a multilayer ceramic substrate that can solve the above-described problems.

  Another object of the present invention is to provide a multilayer ceramic substrate obtained by the manufacturing method described above.

  The present invention relates to a plurality of substrate green layers containing and laminated with a low-temperature sintered ceramic material, and a sintering temperature of the low-temperature sintered ceramic material disposed so as to be in contact with the principal surfaces of the plurality of substrate green layers. A raw laminate comprising a plurality of constraining green layers formed by dispersing inorganic material powder that is not sintered in an organic binder, and a substrate green layer and / or a wiring conductor provided in connection with the constraining green layer. A step of producing a body, and a step of firing a raw laminated body while exerting a restraining force for restraining shrinkage on the green layer for the substrate by the restraining green layer under a condition in which the low-temperature sintered ceramic material is sintered. In order to solve the above technical problem, a plurality of restraining greases provided in the raw laminate are firstly directed to a method for manufacturing a multilayer ceramic substrate. Of the layers, the constraining green layer at the outermost positions in the stacking direction is characterized in that is to have a higher binding than constraining green layer in an intermediate position.

  When the raw laminate described above includes five or more constraining green layers, the constraining force is preferably increased stepwise as the constraining green layer is closer to the outermost position in the stacking direction. .

  In order to generate the difference in restraining force as described above between the plurality of restraining green layers included in the raw laminate, in the first exemplary embodiment, the restraining green layer at the outermost position in the stacking direction is used. Is thicker than the constraining green layer in the middle position, and in the second exemplary embodiment, the ratio of the inorganic material powder to the organic binder in the constraining green layer in the outermost position in the stacking direction is In the third exemplary embodiment, the ratio of the inorganic material powder to the glass component in the outermost constraining green layer in the stacking direction is higher than the ratio of the inorganic material powder to the organic binder in the constraining green layer. The ratio is higher than the ratio of the inorganic material powder to the glass component in the constraining green layer in the middle position, and in the fourth exemplary embodiment, The particle size of the inorganic material powder in constraining green layer at the outermost positions in the stacking direction is smaller than the particle size of the inorganic particle in the constraining green layer in an intermediate position.

  In the method for manufacturing a multilayer ceramic substrate according to the present invention, among the plurality of constraining green layers provided in the raw laminate, the constraining green layer at the outermost position in the stacking direction forms the outermost layer of the raw laminate. It is preferable.

  The present invention is also directed to a multilayer ceramic substrate obtained by the manufacturing method as described above.

  A multilayer ceramic substrate according to the present invention is a multilayer ceramic substrate obtained by firing a green laminate, and includes a plurality of ceramic layers for a substrate and a ceramic for a substrate including and laminated with a low-temperature sintered ceramic material A portion of the material included in the ceramic layer for the substrate is disposed so as to be in contact with each of the principal surfaces of the plurality of layers, and includes an inorganic material powder that does not sinter at the sintering temperature of the low-temperature sintered ceramic material. A plurality of constraining layers to which the inorganic material powder is fixed by permeation, and a wiring conductor provided in association with the ceramic layer for substrate and / or the constraining layer. The constraining layer located at the outermost position in the substrate is applied to suppress the shrinkage of the green layer for the substrate to be the ceramic layer for the substrate in the firing process. That binding force, are characterized by higher than binding of the constraining layer in an intermediate position.

  When the multilayer ceramic substrate according to the present invention includes five or more constraining layers, it is preferable that the above-described constraining force be higher stepwise as the constraining layer is closer to the outermost position in the stacking direction.

  In the multilayer ceramic substrate according to the present invention, of the plurality of constraining layers, in the first exemplary embodiment, the constraining layer at the outermost position in the stacking direction is thicker than the constraining layer at the intermediate position, In the exemplary embodiment of the present invention, the ratio of the inorganic material powder to the organic binder contained in the constraining green layer that is to be the outermost constraining layer in the stacking direction is such that the constraining layer to be the constraining layer in the intermediate position In the third exemplary embodiment, the ratio of the inorganic material powder to the glass component in the constraining layer at the outermost position in the stacking direction is higher than the ratio of the inorganic material powder to the organic binder contained in the green layer. Higher than the ratio of the inorganic material powder to the glass component in the constraining layer in the intermediate position, and in the fourth exemplary embodiment, The particle size of the inorganic material powder in the layer is smaller than the particle diameter of the inorganic particle in the constraining layer in an intermediate position.

  Of the plurality of constraining layers, the constraining layer at the outermost position in the stacking direction preferably forms the outermost layer of the multilayer ceramic substrate.

  According to the present invention, it is possible to produce a multilayer ceramic substrate that is unlikely to cause form defects such as warping, distortion, and undulation, and that has high accuracy with respect to the form. The reason is as follows.

  If the constraining force that can be exerted by the constraining green layer at the outermost position in the stacking direction increases, the green layer for the substrate at the outermost position contracts in the main surface direction as compared with the green layer for the substrate at the intermediate position. It becomes difficult to do. Therefore, compared with the restraining force exerted by the constraining green layer at the intermediate position, the restraining force exerted by the constraining green layer at the outermost position is increased compared with the base green layer at the intermediate position. Since the substrate green layer at the outer position is less contracted, the substrate green layer at the intermediate position is less likely to contract by being pulled by the substrate green layer at the outermost position. In addition, in multilayer ceramic substrates, it is less likely to cause morphological defects such as warpage, distortion, and undulation that may occur during the ceramic sintering stage, so that the morphological accuracy is increased. Can do. For this reason, the form accuracy of the multilayer ceramic substrate can be increased by increasing the restraining force exerted by the restraining green layer at the outermost position.

  If the restraining force exerted by the constraining green layer at the outermost position is weak, the restraining force exerted by the constraining green layer at the intermediate position is higher. The force determines the form accuracy of the multilayer ceramic substrate. At the intermediate position, the number of green layers for the substrate is large, and the arrangement of the wiring conductors differs depending on the product. Therefore, the amount of warpage differs depending on the product and is not stable. Therefore, when the restraining force exerted by the restraining green layer at the outermost position is low, the form accuracy of the multilayer ceramic substrate is not stable. On the other hand, if the restraining force exerted by the constraining green layer at the outermost position is high as in the present invention, the restraining force by the constraining green layer at the intermediate position is unstable, and the influence of the wiring conductor Even if there is, the form accuracy of the multilayer ceramic substrate can be stabilized.

  In this invention, when the raw laminate includes five or more constraining green layers, the restraining force is increased stepwise as the constraining green layer is closer to the outermost position in the stacking direction. The restraining force exerted by the constraining green layer in the intermediate position is strengthened by the restraining force exerted by the constraining green layer in the outermost position, thereby strengthening the form in which the constraining green layer in the middle position and the green layer for the substrate are pulled. Even if it is unstable, the form accuracy of the multilayer ceramic substrate can be more reliably stabilized.

  Note that the effects of improving and stabilizing these morphological precisions are more prominent when the outermost constraining layer forms the outermost layer of the multilayer ceramic substrate.

  FIG. 1 is a cross-sectional view showing a multilayer ceramic substrate 1 according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a raw laminate 2 produced to obtain the multilayer ceramic substrate 1 shown in FIG. The multilayer ceramic substrate 1 is obtained by firing a raw laminate 2.

  Referring to FIG. 1, a multilayer ceramic substrate 1 includes a plurality of base ceramic layers 3 to 7 including a low-temperature sintered ceramic material and laminated. The multilayer ceramic substrate 1 includes a plurality of constraining layers 8 to 13 arranged so as to be in contact with the principal surfaces of the plurality of base ceramic layers 3 to 7, respectively. The constraining layers 8 to 13 include an inorganic material powder that does not sinter at the sintering temperature of the low-temperature sintered ceramic material described above, and a part of the material contained in the base ceramic layers 3 to 7 in contact therewith penetrates. The inorganic material powder is fixed.

  In this embodiment, the constraining layers 8 and 13 are arranged so as to form the outermost layer of the multilayer ceramic substrate 1, and the constraining layer is formed along all the interfaces between each of the plurality of substrate ceramic layers 3 to 7. Although 9-12 are arrange | positioned, the interface between the ceramic layers 3-7 for base | substrates in which a constraining layer is not arrange | positioned may exist.

  The multilayer ceramic substrate 1 further includes a wiring conductor 14 provided in association with the base ceramic layers 3 to 7 and / or the constraining layers 8 to 13. As the wiring conductor 14, for example, an external conductor film 15 provided on the outer surface of the multilayer ceramic substrate 1, an internal conductor film 16 extending along the main surfaces of the substrate ceramic layers 3 to 7 inside the multilayer ceramic substrate 1, In addition, there is a via-hole conductor 17 extending so as to penetrate in the thickness direction of the base ceramic layers 3 to 7 and the constraining layers 8 to 13.

  In such a multilayer ceramic substrate 1, the thicknesses T <b> 3 to T <b> 7 of the base ceramic layers 3 to 7 are the same, but attention is paid to the thicknesses T <b> 8 to T <b> 13 of the constraining layers 8 to 13. Thicknesses T8 and T13 of certain constraining layers 8 and 13 are thicker than thicknesses T9 to T12 of constraining layers 9 to 12 in the middle position.

  In order to obtain the multilayer ceramic substrate 1 described above, the raw laminate 2 shown in FIG. 2 is produced.

  The raw laminate 2 includes a plurality of base green layers 23 to 27 that include a low-temperature sintered ceramic material and are laminated. The base green layers 23 to 27 become the above-described base ceramic layers 3 to 7 after firing. Accordingly, the thicknesses T23 to T27 of the base green layers 23 to 27 are the same.

  The raw laminate 2 also includes a plurality of constraining green layers 28 to 33 disposed so as to be in contact with the principal surfaces of the plurality of base green layers 23 to 27, respectively. The constraining green layers 28 to 33 have a composition in which an inorganic material powder that is not sintered at the sintering temperature of the low-temperature sintered ceramic material is dispersed in an organic binder. The constraining green layers 28 to 33 become the constraining layers 8 to 13 described above after firing. Accordingly, the thicknesses T28 and T33 of the constraining green layers 28 and 33 at the outermost position in the stacking direction are set to be thicker than the thicknesses T29 to T32 of the constraining green layers 29 to 32 at the intermediate position. In the process, a higher restraining force can be exerted to suppress shrinkage.

  The raw laminate 2 includes the wiring conductor 14 provided in association with the base green layers 23 to 27 and / or the constraining green layers 28 to 33. As described above, the wiring conductor 14 includes the outer conductor film 15, the inner conductor film 16, and the via-hole conductor 17. At this stage, the wiring conductor 14 is made of an unsintered conductive paste.

  In order to produce the raw laminate 2, the following method is usually employed.

  First, a green sheet for a substrate, which is each of the green layers 23 to 27 for the substrate, is prepared. The green sheet for a base is made by adding an organic vehicle and a plasticizer from an organic binder and a solvent to a low-temperature sintered ceramic material, and mixing them to make a slurry. It can be obtained by molding into a sheet by the method and drying.

  As the low-temperature sintered ceramic material, for example, a glass ceramic in which alumina and borosilicate glass are mixed, a Ba-Al-Si-B oxide ceramic that generates a glass component during firing, silver, In order to enable simultaneous firing even when the wiring conductor 14 is formed of a low melting point metal such as copper, it can be fired at a temperature of, for example, 1000 ° C. or less, and a part thereof (for example, a glass component) during firing. That can penetrate into the constraining green layers 28 to 33 are used.

  In order to facilitate the penetration of the above materials, the thicknesses T23 to T27 of the base green layers 23 to 27 are 5 to 150 μm after firing, that is, in the state of the base ceramic layers 3 to 7. It is preferable to be selected within the range.

The constraining green layers 28 to 33 include an inorganic material powder that does not sinter at the sintering temperature of the low-temperature sintered ceramic material as described above. For example, alumina powder or zirconia powder is used as the inorganic material powder. It is preferable. While using high intensity | strength alumina powder and zirconia powder as inorganic material powder, and increasing these content, the intensity | strength of the multilayer ceramic substrate after baking can be raised. In addition, as the inorganic material powder, TiO ₂ powder, SiO ₂ , Nb ₂ O ₅ powder, Ta ₂ O ₅ powder, or the like can also be used.

  The constraining green layers 28 to 33 are prepared by adding an organic vehicle and an organic vehicle composed of an organic binder and a solvent and a plasticizer to the above-described inorganic material powder and mixing them to form a slurry. It can be formed by coating on the surface of the green sheet for use and drying.

  The thicknesses T28 to T33 of the constraining green layers 28 to 33 are premised on satisfying the above-described conditions, but the thicknesses T28 and T33 of the constraining green layers 28 and 33 at the outermost positions are fired. Later, that is, in each of the constraining layers 8 and 13, it is preferably selected within a range of 1 to 15 μm, and the thicknesses T29 to T32 of the constraining green layers 29 to 32 at the intermediate positions are determined after firing. In other words, it is preferably selected within the range of 1 to 10 μm in the state of the constraining layers 9 to 12.

  The wiring conductor 14 is formed by applying a conductive paste. More specifically, for the outer conductor film 15 and the inner conductor film 16, the conductive paste is a predetermined one of the base green layers 23 to 27 or a predetermined one of the constraining green layers 28 to 33, for example, by screen printing. Printed on top. On the other hand, in the via-hole conductor 17, through holes are provided in predetermined ones of the base green layers 23 to 27 and predetermined green layers 28 to 33, and a conductive paste is filled in the through holes. Formed by.

  As the conductive component contained in the conductive paste, for example, Cu, Ag, Ni or Pd, oxides thereof, or alloys containing these metals can be used. preferable.

  The conductive paste for forming the outer conductor film 15 is mainly composed of Cu, and includes ceramic materials contained in the base green layers 23 to 27 and inorganic contained in the constraining green layers 28 to 33. It is preferable to use a material added with materials. In particular, the inorganic material contained in the constraining green layers 28 to 33 is preferably used in a state of being attached to the surface of the Cu particles. When such a conductive paste is used for forming the external conductor film 15, it is possible to substantially prevent sintering shrinkage of the conductive paste alone, and the conductive property of the wiring conductor 14 after firing is reduced. Degradation can be minimized.

  Next, ceramic green sheets to be each of the green layers 23 to 27 for the substrate are laminated according to a predetermined order and direction and pressed to obtain a raw laminate 2 as shown in FIG.

  Next, the raw laminate 2 is fired under conditions under which the low-temperature sintered ceramic material is sintered, whereby the multilayer ceramic substrate 1 is obtained.

  In the firing step described above, the constraining green layers 28 to 33 themselves do not substantially shrink. Therefore, the constraining green layers 28 to 33 exert a constraining force that suppresses contraction in the principal surface direction of the base green layers 23 to 27. For this reason, the green layers 23 to 27 for the substrate are substantially shrunk only in the thickness direction as the low-temperature sintered ceramic material contained therein is sintered while the shrinkage in the principal surface direction is suppressed. The base ceramic layers 3 to 7 in the obtained multilayer ceramic substrate 1 are formed. On the other hand, in the constraining green layers 28 to 33, a part of the material such as the glass component contained in the base green layers 23 to 27 permeates, thereby restraining the inorganic material powder in a fixed state. Layers 8-13 are formed.

  The multilayer ceramic substrate 1 thus obtained has a high dimensional accuracy with respect to the principal surface direction. In addition, the multilayer ceramic substrate 1 is less prone to form defects such as warping, distortion, and undulation, and has a high accuracy in form. The reason is as follows.

  The thicknesses T28 and T33 of the constraining green layers 28 and 33 in the outermost position are thicker than the thicknesses T29 to T32 of the constraining green layers 29 to 32 in the intermediate position, and therefore the constraining green layer in the outermost position. The restraining force exerted by 28 and 33 is higher than the restraining force exerted by the constraining green layers 29 to 32 in the intermediate position. Therefore, the substrate green layers 23 and 27 at the outermost position are less contracted than the substrate green layers 24 to 26 at the intermediate position, and are pulled by the substrate green layers 23 and 27 at the outermost position. In this way, the base green layers 24 to 26 at the intermediate positions are also difficult to contract. For this reason, the form accuracy of the multilayer ceramic substrate 1 can be increased by increasing the restraining force exerted by the restraining green layers 28 and 33 at the outermost position.

  The multilayer ceramic substrate 1 obtained as described above is subjected to a surface treatment such as Ni and / or Au electroless plating on the outer conductor film 15 as necessary, and then a desired electronic component. (Not shown) is mounted on the multilayer ceramic substrate 1 so as to be electrically connected to the external conductor film 15. Examples of electronic components mounted in this way include active elements such as transistors, ICs, and LSIs, and passive elements such as chip capacitors, chip resistors, chip thermistors, and chip inductors.

  FIG. 3 is a sectional view showing a multilayer ceramic substrate 1a according to the second embodiment of the present invention. FIG. 4 shows a raw laminate 2a produced to obtain the multilayer ceramic substrate 1a shown in FIG. It is sectional drawing. 3 and 4 correspond to FIGS. 1 and 2, respectively. In FIGS. 3 and 4, elements corresponding to those shown in FIGS. 1 and 2 are denoted by the same reference numerals. The overlapping description is omitted.

  In the second embodiment, the thicknesses T3 to T7 of the ceramic layers 3 to 7 for the base are not the same as each other, and therefore the thicknesses T23 to T27 of the green layers 23 to 27 for the base are not the same. It is characterized by. More specifically, the thickness T4 of the substrate ceramic layer 4 is the largest among the ceramic layers 3 to 7 for the substrate, the thickness T6 of the ceramic layer 6 for the substrate is the second largest, and the ceramic layers 3 and 7 for the substrate. Thicknesses T3 and T7 are the third thickest, and the thickness T5 of the base ceramic layer 5 is the thinnest. The relationship between the thicknesses T23 to T27 of the green layers 23 to 27 for the substrate is the same as the relationship between the thicknesses T3 to T7 of the ceramic layers 3 to 7 for the substrate.

  When the thickness relationship is as described above, the thickest substrate green layer 24 inherently has the highest shrinkage capacity in the firing step. The layers 23 and 27 and the base green layer 25 are arranged in this order. Therefore, when no countermeasure is taken, there is a case where a defective shape such as warpage is caused in the multilayer ceramic substrate 1a as a result of the firing process.

  In order to suppress this defective shape, in the technique described in Patent Document 1 described above, each of the constraining green layers 28 to 33 has a thickness T28 to T according to the thickness T23 to T27 of each of the base green layers 23 to 27. T33 is made different so that the restraining forces that the restraining green layers 28 to 33 exert on the base green layers 23 to 27 to suppress shrinkage are different from each other.

  On the other hand, in this embodiment, the thicknesses T28 and T33 of the constraining green layers 28 and 33 at the outermost position are simply made thicker than the thicknesses T29 to T32 of the constraining green layers 29 to 32 at the intermediate position. Therefore, it is intended to suppress morphological defects such as warpage. That is, basically, the respective thicknesses T28 to T33 of the constraining green layers 28 to 33 can be determined irrespective of the thicknesses T23 to T27 of the base green layers 23 to 27.

  FIG. 5 is a sectional view showing a multilayer ceramic substrate 1b according to the third embodiment of the present invention. FIG. 6 is a cross-sectional view showing a raw laminate 2b produced to obtain the multilayer ceramic substrate 1b shown in FIG. 5 and 6, elements corresponding to those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted.

  In the third embodiment, five or more constraining layers 8 to 13 or five or more constraining green layers 28 to 33 are provided, and the thickness of the constraining layer or the constraining green layer closer to the outermost position in the stacking direction is stepwise. It is characterized by being made thicker. That is, the relationship of thickness T8 = thickness T13> thickness T9 = thickness T12> thickness T10 = thickness T11 is satisfied. Therefore, the restraining force is higher stepwise as the restraining layer or the restraining green layer is closer to the outermost position in the stacking direction. That is, there is a relationship of thickness T28 = thickness T33> thickness T29 = thickness T32> thickness T30 = thickness T31.

  According to this embodiment, the shape in which the restraining green layers 29 to 32 and the base green layers 23 to 27 in the intermediate position are pulled by the restraining force exerted by the restraining green layers 28 and 33 in the outermost position is strengthened. Therefore, even if the restraining force exerted by the restraining green layers 29 to 32 at the intermediate position is unstable, the form accuracy of the multilayer ceramic substrate 1b can be more reliably stabilized.

  FIG. 7 is a sectional view showing a multilayer ceramic substrate 1c according to the fourth embodiment of the present invention. FIG. 8 is a cross-sectional view showing a raw laminate 2c produced to obtain the multilayer ceramic substrate 1c shown in FIG. 7 and 8, elements corresponding to those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted.

  In the fourth embodiment, the restraining green layers 28 to 33 are provided with a difference in restraining force between the restraining green layers 28 and 33 at the outermost position and the restraining green layers 29 to 32 at the intermediate position. It is characterized by not being based on the thickness T28 to T33, but based on the composition of the constraining green layers 28 to 33. That is, in the fourth embodiment, the thicknesses T8 to T13 of the constraining layers 8 to 13 are the same, and the thicknesses T28 to T33 of the constraining green layers 28 to 33 are the same, but the stacking direction The ratio of the inorganic material powder to the organic binder in the constraining green layers 28 and 33 in the outermost position in the region is higher than the ratio of the inorganic material powder to the organic binder in the constraining green layers 29 to 32 in the intermediate position. Thus, the constraining green layers 28 and 33 at the outermost position can be applied with a higher restraining force than the constraining green layers 29 to 32 at the intermediate position.

  7 and 8 are also referred to for explaining the fifth and sixth embodiments of the present invention.

  In the fifth embodiment, when the constraining green layers 28 to 33 include a glass component, the ratio of the inorganic material powder to the glass component in the constraining green layers 28 and 33 in the outermost position in the stacking direction is in the middle position. The constraining green layers 29 to 32 are made higher than the inorganic material powder for the glass component, so that the constraining green layers 28 and 33 at the outermost position are higher than the constraining green layers 29 to 32 at the intermediate position. High restraint force can be given.

  In the sixth embodiment, the particle size of the inorganic material powder in the constraining green layers 28 and 33 in the outermost position in the stacking direction is larger than the particle size of the inorganic material powder in the constraining green layers 29 to 32 in the intermediate position. So that the constraining green layers 28 and 33 in the outermost position can provide a higher restraining force than the constraining green layers 29 to 32 in the intermediate position.

  FIG. 9 is a sectional view showing a multilayer ceramic substrate 1d according to the seventh embodiment of the present invention. FIG. 10 is a cross-sectional view showing a raw laminate 2d produced to obtain the multilayer ceramic substrate 1d shown in FIG. 9 and 10, elements corresponding to those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted.

  In the seventh embodiment, the constraining layers 8 and 13 at the outermost position in the stacking direction do not form the outermost layer of the multilayer ceramic substrate 1d, and similarly, the constraining green layer 28 and the outermost layer at the outermost position. 33 is characterized by not forming the outermost layer of the raw laminate 2d.

  The effects of improving and stabilizing the form accuracy of the multilayer ceramic substrate according to the present invention and improving the strength are that the constraining layer located at the outermost position forms the outermost layer of the multilayer ceramic substrate as in the first to sixth embodiments. Or the constraining green layer at the outermost position forms the outermost layer of the raw laminate, which appears more prominently. In the seventh embodiment shown in FIGS. 9 and 10, the constraining layers 8 and 13 at the outermost position do not form the outermost layer of the multilayer ceramic substrate 1d, or the restraining layers are at the outermost position. Even if the green layers 28 and 33 do not form the outermost layer of the raw laminated body 2d, it is meaningful to clearly show that it is within the scope of the present invention.

  As mentioned above, although the illustrated embodiment of the present invention has been described, other various modifications are possible within the scope of the present invention.

  For example, the illustrated structure of the multilayer ceramic substrate 1 and the raw laminated body 2 is merely an example, and the number of laminated layers, arrangement of wiring conductors, and the like can be variously changed.

  Further, in the present invention, among the plurality of constraining green layers 28 to 33 provided in the raw laminate 2 or the like, the constraining green layers 28 and 33 that are at the outermost positions in the stacking direction are the constraining greens that are at the intermediate positions. Although it is an essential condition to have a higher restraining force than the layers 29 to 32, if this condition is satisfied, for example, the restraining force is different between the restraining green layers 28 and 33 at the outermost position. Alternatively, the restraining force may be different between the restraining green layers 29 to 32 in the intermediate position.

  In the embodiment in which the constraining green layer at the outermost position in the stacking direction forms the outermost layer of the raw laminate among the plurality of constraining green layers provided in the raw laminate. The linear expansion coefficient of the green layer for use may be smaller than the linear expansion coefficient of the constraining green layer and the base green layer at the intermediate position. In this case, the effect that the strength of the fired multilayer ceramic substrate is improved can be obtained.

  Further, at least one of the fourth to sixth embodiments may be combined with each of the first to third and seventh embodiments.

  Next, an example of an experiment conducted for confirming the effect of the present invention will be described.

As a sample, a multilayer ceramic substrate provided with 10 ceramic layers for a substrate was prepared. In this multilayer ceramic substrate, the constraining layer is disposed so as to form an outermost layer along the interface between the ceramic layers for the substrate. The ceramic layer for the substrate was composed of a Ba—Al—Si—B based oxide ceramic, and each thickness was 20 μm after firing. On the other hand, the constraining layer contains Al ₂ O ₃ powder as an inorganic material powder, and further contains BaO—Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ —CaO with respect to 60 parts by weight of this Al ₂ O _3. It was set as the composition containing 40 weight part of glass components made into a component. The thickness of the constraining layer at the outermost position and the thickness of the constraining layer at the intermediate position were set as shown in Table 1. The planar dimensions of the multilayer ceramic substrate according to each sample were 4 inches (about 10 cm) square.

  About the multilayer ceramic substrate which concerns on each sample, the curvature amount and bending strength were measured. The bending strength was determined based on a three-point bending strength test method according to “JIS R 1601”. These results are shown in Table 1.

  Referring to Table 1, according to Samples 2 and 3 in which the thickness of the constraining layer at the outermost position is larger than the thickness of the constraining layer at the intermediate position, the thickness of the constraining layer at the outermost position is It can be seen that the amount of warpage is small and the bending strength is increased as compared with Sample 1 in which the thickness of a certain constraining layer is equal.

1 is a cross-sectional view showing a multilayer ceramic substrate 1 according to a first embodiment of the present invention. It is sectional drawing which shows the raw laminated body 2 produced in order to obtain the multilayer ceramic substrate 1 shown in FIG. It is sectional drawing which shows the multilayer ceramic substrate 1a by 2nd Embodiment of this invention. It is sectional drawing which shows the raw laminated body 2a produced in order to obtain the multilayer ceramic substrate 1a shown in FIG. It is sectional drawing which shows the multilayer ceramic substrate 1b by 3rd Embodiment of this invention. It is sectional drawing which shows the raw laminated body 2b produced in order to obtain the multilayer ceramic substrate 1b shown in FIG. It is sectional drawing which shows the multilayer ceramic substrate 1c by 4th, 5th or 6th embodiment of this invention. It is sectional drawing which shows the raw laminated body 2c produced in order to obtain the multilayer ceramic substrate 1c shown in FIG. It is sectional drawing which shows the multilayer ceramic substrate 1d by 7th Embodiment of this invention. It is sectional drawing which shows the raw laminated body 2d produced in order to obtain the multilayer ceramic substrate 1d shown in FIG.

Explanation of symbols

1, 1a, 1b, 1c, 1d Multilayer ceramic substrate 2, 2a, 2b, 2c, 2d Raw laminated body 3-7 Ceramic layer for substrate 8-13 Constraining layer 14 Wiring conductor 23-27 Green layer for substrate 28-33 Constraining green layer T3 to T7 Thickness of ceramic layer for substrate T8 to T13 Thickness of constraining layer T23 to T27 Thickness of green layer for substrate T28 to T33 Thickness of constraining green layer

Claims (14)

A plurality of green layers for a substrate including and laminated with a low-temperature sintered ceramic material, and arranged so as to be in contact with main surfaces of the plurality of green layers for the substrate, and sintered at the sintering temperature of the low-temperature sintered ceramic material. A raw laminate comprising a plurality of constraining green layers in which inorganic material powder that is not bonded is dispersed in an organic binder, and the substrate green layer and / or a wiring conductor provided in association with the constraining green layer Producing a body;
Firing the raw laminate while exerting a restraining force for restraining shrinkage on the base green layer by the restraining green layer under conditions where the low-temperature sintered ceramic material is sintered. A method for producing a multilayer ceramic substrate, comprising:
Among the plurality of constraining green layers provided in the raw laminate, a constraining green layer at the outermost position in the stacking direction has a higher restraining force than the constraining green layer at an intermediate position. A method for manufacturing a substrate.   The raw laminate includes five or more constraining green layers, and the restraining force is gradually increased as the constraining green layer is closer to the outermost position in the stacking direction. Item 2. A method for producing a multilayer ceramic substrate according to Item 1.   3. The constraining green layer at the outermost position in the stacking direction among the plurality of constraining green layers provided in the raw laminate is thicker than the constraining green layer at an intermediate position. For producing a multilayer ceramic substrate.   Of the plurality of constraining green layers provided in the raw laminate, the ratio of the inorganic material powder to the organic binder in the constraining green layer at the outermost position in the stacking direction is the constraining green layer at an intermediate position The manufacturing method of the multilayer ceramic substrate in any one of Claims 1 thru | or 3 higher than the ratio of the said inorganic material powder with respect to the said organic binder in.   The constraining green layer includes a glass component, and the inorganic material powder with respect to the glass component in the constraining green layer at the outermost position in the stacking direction among the plurality of constraining green layers provided in the raw laminate. 5. The method for producing a multilayer ceramic substrate according to claim 1, wherein the ratio is higher than the ratio of the inorganic material powder to the glass component in the constraining green layer at an intermediate position.   Among the plurality of constraining green layers included in the raw laminate, the inorganic material powder in the constraining green layer at the outermost position in the stacking direction has a particle size of the inorganic in the constraining green layer at an intermediate position. The method for manufacturing a multilayer ceramic substrate according to any one of claims 1 to 5, wherein the method is smaller than the particle size of the material powder.   The constraining green layer at the outermost position in the stacking direction among the plurality of constraining green layers provided in the raw laminate forms the outermost layer of the raw laminate. A method for producing a multilayer ceramic substrate according to any one of the above. A multilayer ceramic substrate obtained by firing a raw laminate,
A plurality of substrate ceramic layers comprising and laminated a low temperature sintered ceramic material;
Included in the ceramic layer for a substrate that is disposed so as to be in contact with the principal surfaces of the plurality of ceramic layers for the substrate, and that does not sinter at the sintering temperature of the low-temperature sintered ceramic material, and is in contact with the inorganic material powder A plurality of constraining layers to which the inorganic material powder is fixed by infiltration of a part of the material to be infiltrated,
A wiring conductor provided in association with the ceramic layer for the substrate and / or the constraining layer,
Among the plurality of constraining layers, for the constraining layer at the outermost position in the stacking direction, the constraining force that can be applied to the base green layer to be the base ceramic layer in the firing step for suppressing shrinkage, A multilayer ceramic substrate that is higher than the restraining force of the constraining layer in the middle position.   The multilayer ceramic substrate according to claim 8, further comprising five or more layers of the constraining layer, wherein the constraining force is higher stepwise as the constraining layer is closer to the outermost position in the stacking direction.   10. The multilayer ceramic substrate according to claim 8, wherein among the plurality of constraining layers, a constraining layer located at an outermost position in the stacking direction is thicker than a constraining layer located at an intermediate position.   Of the plurality of constraining layers, the ratio of the inorganic material powder to the organic binder contained in the constraining green layer that should be the outermost constraining layer in the stacking direction should be the constraining layer in the middle position. 11. The multilayer ceramic substrate according to claim 8, wherein the ratio is higher than the ratio of the inorganic material powder to the organic binder contained in the constraining green layer.   The constraining layer includes a glass component, and the ratio of the inorganic material powder to the glass component in the constraining layer at the outermost position in the stacking direction among the plurality of constraining layers is the glass component in the constraining layer at an intermediate position. 12. The multilayer ceramic substrate according to claim 8, wherein the ratio is higher than the ratio of the inorganic material powder to the substrate.   The particle size of the inorganic material powder in the constraining layer at the outermost position in the stacking direction among the plurality of constraining layers is smaller than the particle size of the inorganic material powder in the constraining layer at the intermediate position. The multilayer ceramic substrate according to any one of 12 above.   The multilayer ceramic substrate according to any one of claims 8 to 13, wherein a constraining layer at an outermost position in the stacking direction among the plurality of constraining layers forms an outermost layer of the multilayer ceramic substrate.

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