JP2006181738A - Ceramic laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic laminate reduced in the occurrence of a crack by reducing the strain in the vicinity of the side surface of the laminate. <P>SOLUTION: In the ceramic laminate constituted by laminating a plurality of ceramic insulating layers, the ceramic insulating layers are composed of first ceramic insulating layers 1a-1e exposed to the side surface of the ceramic laminate and the second ceramic insulating layers 1f-1i, which are interposed between the first ceramic insulating layers 1a-1e and have a small outer shape as compared with the outer shape of each of the first ceramic insulating layers 1a-1e and are composed of a composition different from that of the first ceramic insulating layers 1a-1e. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ceramic laminate such as a multilayer wiring board used for a semiconductor device, a composite electronic component or the like.

  Conventionally, ceramic laminates such as multilayer wiring boards have been widely used in semiconductor devices and composite electronic components.

Such a conventional ceramic laminate is formed by laminating a plurality of ceramic insulating layers, and a wiring conductor is provided between the insulating layers. Moreover, in order to configure functions such as capacitors and inductors, or to increase the dimensional accuracy, some ceramic insulating layers have different compositions (for example, Patent Document 1, 2).
JP-A-2-309694 JP 2001-15875 A

  However, ceramic laminates made by laminating two or more types of ceramic insulating layers with different compositions have different coefficients of thermal expansion when a thermal history is applied during assembly of electrical circuits, etc. Becomes larger. The strain at the boundary between the ceramic insulating layers having different compositions causes a crack or the like starting from a portion exposed on the side surface of the ceramic laminate.

  Further, since the sintering start temperature is different due to the different composition, the strain becomes large at the boundary during the firing step in the production, and the above-described cracks and the like are generated.

  The present invention has been devised in view of the above-described drawbacks, and an object of the present invention is to provide a ceramic laminate in which generation of cracks is reduced by reducing strain near the side surface.

  The ceramic laminate of the present invention is a ceramic laminate formed by laminating a plurality of ceramic insulating layers, wherein the ceramic insulating layer includes a first ceramic insulating layer exposed on a side surface of the ceramic laminate, and the first ceramic insulating layer. And a second ceramic insulating layer having a composition smaller than that of the first ceramic insulating layer and having a composition different from that of the first ceramic insulating layer. To do.

  In the ceramic laminate of the present invention, the first ceramic insulating layer is thicker than the second ceramic insulating layer.

  Furthermore, the ceramic laminate of the present invention is characterized in that the first ceramic insulating layer has a higher sintering start temperature than the second ceramic insulating layer.

  According to the ceramic laminate of the present invention, since the composition of the first ceramic insulating layer exposed on the side surface of the ceramic laminate is the same, the thermal expansion coefficient becomes uniform near the side surface, and at the boundary of the ceramic insulating layer. This reduces the distortion and reduces the occurrence of cracks and the like.

  Further, according to the ceramic laminate of the present invention, by reducing the thickness of the second ceramic insulating layer that is not exposed to the side surface, the influence of not forming the second ceramic insulating layer near the side surface is reduced, and the flatness Will be better.

  Furthermore, according to the ceramic laminate of the present invention, the sintering start temperature of the first ceramic insulating layer exposed on the side surface is higher than that of the second ceramic insulating layer not exposed. In the firing step, after the sintering in the vicinity of the side surface is completed, the strain due to the shrinkage stress is reduced, and the generation of cracks and the like can be further reduced.

  Hereinafter, the ceramic laminate of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view of a ceramic laminate according to an embodiment of the present invention. A ceramic laminate 1 shown in FIG. 1 is roughly composed of first ceramic insulating layers 1a to 1e and a second ceramic insulation. The layers 1f to 1i are stacked. The ceramic laminate 1 of the present embodiment is a multilayer wiring board having wiring conductors 2 and 3 formed on the surface layer and inside. The surface layer wiring conductor 2 mainly functions as a connection pad serving as an electronic component element mounting portion, and the internal wiring conductor 3 interposed between the insulating layers mainly includes wiring for electrically connecting each circuit element and an inductor. -Functions as a circuit element such as a capacitor. The wiring conductor 2 on the surface layer and the internal wiring conductor, or the internal wiring conductors 3 interposed between different ceramic insulating layers are electrically connected by a via-hole conductor 4.

  As the material for the first ceramic insulating layers 1a to 1e, a glass-ceramic material that can be fired at a relatively low temperature of, for example, 800 ° C. to 1200 ° C. is preferably used, and the thickness thereof is, for example, 10 to 300 μm. Is set. The glass-ceramic material includes glass powder and ceramic powder. The glass powder is contained in an amount of 30 to 100 parts by weight, and the material excluding the glass powder is the ceramic powder.

As the material of the second ceramic insulating layers 1f to 1i, a glass-ceramic material is preferably used similarly to the first ceramic insulating layers 1a to 1e, and the thickness thereof is set to 2 to 150 μm, for example. . And
Although the first ceramic insulating layers 1a to 1e constitute the side surfaces of the ceramic laminate 1, the second ceramic insulating layers 1f to 1i are the outer shapes (when viewed in plan) of the first ceramic insulating layers 1a to 1e. Since the outer shape is smaller than that of the outer peripheral shape, the cross section as shown in FIG. 1 is not exposed to the side surface of the ceramic laminate 1.

  In the present embodiment, for example, the first ceramic insulating layer is made of a material having a composition of 55 parts by weight of glass powder, and the second ceramic insulating layer is made of a material having a composition of 85 parts by weight of glass powder.

As a specific composition of the glass powder, for example, as essential components, 10 to 70 parts by weight of SiO ₂ , 0.5 to 30 parts by weight of Al ₂ O ₃ , 3 to 60 parts by weight of MgO, and optional components 0 to 35 parts by weight of CaO, 0 to 35 parts by weight of BaO, 0 to 35 parts by weight of SrO, 0 to 20 parts by weight of B ₂ O ₃ , 0 to 30 parts by weight of ZnO, 0 to 10 parts of TiO ₂ Examples include parts by weight, 0 to 3 parts by weight of Na ₂ O, and 0 to 5 parts by weight of Li ₂ O.

The ceramic powder includes at least one selected from Al ₂ O ₃ , SiO ₂ , MgTiO ₃ , CaZrO ₃ , CaTiO ₃ , Mg ₂ SiO ₄ , BaTi ₄ O ₉ , ZrTiO ₄ , SrTiO ₃ , BaTiO ₃ and TiO _2. Can be mentioned.

  According to the combination of the glass powder and the ceramic powder having the above composition, low temperature sintering at 1000 ° C. or less is possible, and as a conductor layer, silver (melting point 960 ° C.), copper (melting point 1083 ° C.), gold (melting point) 1063 ° C.) or the like, and a low-loss circuit can be created. Also, the dielectric constant can be controlled, which is suitable for circuit miniaturization and low loss due to high dielectric constant, or high-speed transmission due to low dielectric constant. In addition, by controlling various compositions within the above range, the firing shrinkage behavior can be easily controlled and changed.

  And in the ceramic laminated body 1 of this embodiment, the 1st ceramic insulating layers 1a-1e are exposed to the side surface of the ceramic laminated body 1, and the 2nd ceramic insulating layers 1f-1i are 1st ceramics. The insulating layer has a different composition, is interposed between the first ceramic insulating layers, and has an outer shape smaller than that of the first ceramic insulating layer.

  As described above, since the compositions of the first ceramic insulating layers 1a to 1e exposed on the side surface of the ceramic laminate 1 are the same, the thermal expansion coefficient becomes uniform near the side surface, and the distortion at the boundary of the ceramic insulating layer occurs. And the occurrence of cracks and the like can be reduced.

  Moreover, since the ceramic laminated body 1 of this embodiment has set the thickness of the 2nd ceramic insulating layers 1f-1i which are not exposed to the side surface thinly, it has the influence that the 2nd ceramic insulating layer was not formed in the side surface vicinity. Less and flatness is improved.

  The wiring conductors 2 and 3 and the via-hole conductor 4 are made of a conductive material including any one of silver, copper, and gold. The wiring conductors 2 and 3 are set to have a thickness of 5 to 25 μm, for example. The diameter of the via-hole conductor 3 can be arbitrarily set. When the thickness of the insulating layer in which the via-hole conductor 3 is embedded is 10 to 300 μm, the diameter of the via-hole conductor 3 is set to 50 to 300 μm, for example. In FIG. 1, the wiring conductor 3 formed inside the ceramic laminate 1 includes, for example, first ceramic insulating layers 1a to 1e on the upper surface side of the conductor layer 3, and second ceramic insulating layers 1f to 1f on the lower surface side. 1i is arranged between the first ceramic insulating layers 1a to 1e and the second ceramic insulating layers 1f to 1i. For example, the first ceramic insulating layer is formed on the lower surface side of the conductor layer 3. The layers 1a to 1e are arranged between the second ceramic insulating layers 1f to 1i and the first ceramic insulating layers 1a to 1e so that the second ceramic insulating layers 1f to 1i are arranged on the upper surface side. It doesn't matter. The via-hole conductor 4 is also formed only in the thickness of the first ceramic layer 1a in FIG. 1, but may be formed so as to penetrate the thickness of each of the second ceramic insulating layers 1f to 1i.

  The ceramic laminate 1 described above is manufactured by, for example, the following method.

  First, the first ceramic insulating layers 1a to 1e and the second ceramic insulating layers 1f to 1i are formed as ceramic green sheets. The ceramic green sheet is made into a slurry by mixing an organic binder, an organic solvent, and a plasticizer as necessary, for example, into a powder obtained by combining the glass powder and the ceramic powder described above, and using this slurry, a doctor blade method or the like. It is obtained by tape forming and cutting to a predetermined dimension.

In the present embodiment, for example, the composition of the powder used in the first ceramic insulating layer 1a~1e the glass powder, the SiO ₂ 33 parts by weight, the _Al 2 _{O 3} 3.4 parts by weight, 13 weight MgO Parts, CaO 15 parts, BaO 0.3 parts, B ₂ O ₃ 0.2 parts, Li ₂ O 0.1 parts, ceramic powder from Al ₂ O ₃ 45 parts by weight It was made. The composition of the powder used for the second ceramic insulating layer 1f~1i the glass powder, the SiO ₂ 40 parts by weight, _Al 2 _{O 3} and 2 parts by weight, 15 parts by weight of MgO, 1 part by weight of CaO, BaO 15 parts by weight, 20 parts by weight of B ₂ O ₃ , 1 part by weight of ZnO, 0.5 parts by weight of TiO ₂ , 0.5 parts by weight of Na ₂ O, 5 parts by weight of Li ₂ O, ceramic powder Was made of a material containing 15 parts by weight of MgTiO ₃ . A slurry obtained by adding an acrylic binder as an organic binder and toluene as an organic solvent to a powder obtained by combining the glass powder and the ceramic powder described above is prepared, and the first ceramic insulating layers 1a to 1e and the second ceramic insulating are respectively prepared. Ceramic green sheets to be the layers 1f to 1i were formed.

  Next, the first ceramic insulating layers 1a to 1e and the second ceramic insulating layers 1f to 1i are bonded together, and through holes are formed in the obtained sheet using a method such as punching with a mold, and the through holes are formed. The via-hole conductor 4 is formed by filling the hole with a conductor paste, and the conductors 2 and 3 are formed by depositing the conductor paste on the main surface of the sheet by a screen printing method or the like.

  The material of the wiring conductors 2 and 3 and the via-hole conductor 4 is formed, for example, by adding ethyl cellulose as an organic binder and 2-2-4-trimethyl-3-3-pentadiol monoisobutyrate as an organic solvent to silver powder. A paste was used.

  And each sheet | seat obtained in this way is laminated | stacked according to a predetermined | prescribed lamination | stacking order, a lamination sheet is formed, and the ceramic laminated body 1 of this embodiment is obtained by baking with a predetermined | prescribed temperature profile. .

  According to the ceramic laminate 1 of the present embodiment, the first ceramic insulating layers 1a to 1e start sintering by having a composition with less glass powder compared to the second ceramic insulating layers 1f to 1i. The temperature is set high. Since the sintering start temperature of the first ceramic insulating layers 1a to 1e exposed on the side surfaces is higher than that of the second ceramic insulating layers 1f to 1i that are not exposed, the sintering start temperature in manufacturing is performed. After the sintering in the vicinity of the side surface is completed, the strain due to the shrinkage stress is reduced, and the ceramic laminate 1 with less occurrence of cracks and the like can be obtained.

  That is, the obtained laminated sheet is in a first temperature region that is lower than the sintering start temperature of the first ceramic insulating layers 1a to 1e and higher than the sintering start temperature of the second ceramic insulating layers 1f to 1i. By heating, the second ceramic insulating layers 1f to 1i are greatly contracted in the thickness direction as compared to the surface direction. Thereafter, the laminated sheet is heated in a second temperature region that is higher than the sintering start temperature of the first ceramic insulating layers 1a to 1e, whereby the first ceramic insulating layers 1a to 1e are compared in the plane direction. Then, the ceramic laminate 1 is obtained by greatly shrinking in the thickness direction and sintering the first and second ceramic insulating layers. That is, when the second ceramic insulating layers 1f to 1i contract, the contraction in the surface direction of the second ceramic insulating layers 1f to 1i is suppressed by the rigidity of the unsintered first ceramic insulating layers 1a to 1e. Further, when the first ceramic insulating layers 1a to 1e contract, the contraction in the surface direction of the first ceramic insulating layers 1a to 1e is suppressed by the rigidity of the second ceramic insulating layers 1f to 1i. As a result, the shrinkage in the surface direction of the laminated sheet is suppressed, and the ceramic laminate 1 can be prevented from warping and can have high dimensional accuracy.

  In the present embodiment, the first ceramic insulating layer has a composition with a sintering start temperature of 783 ° C., and the second ceramic insulating layer has a composition with a sintering start temperature of 690 ° C. As a result, the firing shrinkage of the laminated sheet As a result, the linear shrinkage rate in the surface direction was as small as 3%, and a ceramic laminate 1 with little warpage and deformation could be obtained.

  Further, in the laminated sheet, since the thickness of the second ceramic insulating layers 1f to 1i is set to be thin, the second ceramic insulating layers 1f to 1i that start sintering first have a small stress due to the shrinkage and are not fired. Even in the first ceramic insulating layers 1a to 1e, which do not have high rigidity as a material in the bonded state, shrinkage in the surface direction is more effectively suppressed.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible within the range which does not deviate from the summary of this invention.

  For example, in the above-described embodiment, the ceramic green sheet is used for forming the first ceramic insulating layers 1a to 1e, and this is used by being bonded to the ceramic green sheet used for forming the second ceramic insulating layer. However, instead of this, the first inorganic composition in the form of a paste is used to form the first ceramic insulating layers 1a to 1e, and this is used as the ceramic green sheet used for forming the second ceramic insulating layer. It may be formed directly on the main surface by printing or the like. In this case, the first ceramic insulating layer having a small thickness can be formed relatively easily by applying a paste or the like, compared with the case where the first ceramic insulating layer having a small thickness is formed of a ceramic green sheet or the like. There is also an advantage that the workability when forming the first ceramic insulating layer ceramic becomes good and the productivity of the multilayer circuit board can be improved.

  Furthermore, in the above-described embodiment, the first ceramic insulating layer and the second ceramic insulating layer are alternately laminated to form the ceramic laminated body, but instead, a plurality of first ceramic insulating layers are formed. You may make it form a ceramic laminated body by laminating | stacking a ceramic insulating layer and several 2nd ceramic insulating layers continuously in the thickness direction.

  In addition, the present invention can also be employed in the production of a plurality of mother boards for taking. The plurality of mother boards for taking are divided into a plurality of multilayer circuit boards by cutting along the boundary of each base region corresponding to the ceramic laminate. In this case, the first ceramic insulating layers 1a to 1e are also exposed on the side surface of the plurality of mother boards to be taken, and the second ceramic insulating layers 1f to 1i are first exposed on the side faces of the plurality of mother boards. If it is interposed between the ceramic insulating layers and has a small outer shape compared to the outer shape of the first ceramic insulating layer, the thermal expansion coefficient becomes uniform near the side surface, and at the boundary of the ceramic insulating layer The distortion is reduced and the occurrence of cracks and the like can be reduced.

  Further, in this case, the second ceramic insulating layers 1f to 1i are not formed along the boundaries of the base regions of the mother substrate for taking a plurality of parts. Can be configured.

  In the above-described embodiment, a multilayer wiring board is configured as the ceramic multilayer body 1, but in addition to this, a multilayer ceramic capacitor, a multilayer ceramic inductor, a multilayer ceramic resonator, a multilayer dielectric filter, or the like is configured. It is also possible.

It is sectional drawing of the ceramic laminated body which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ceramic laminated body 1a-1e ... 1st ceramic insulating layer 1f-1i ... 2nd ceramic insulating layer 2, 3 ... Wiring conductor 4 ... Via-hole conductor

Claims (3)

In a ceramic laminate formed by laminating a plurality of ceramic insulating layers,
The ceramic insulating layer includes a first ceramic insulating layer exposed on a side surface of the ceramic laminate,
The second ceramic insulating layer is interposed between the first ceramic insulating layers and has a smaller outer shape than the first ceramic insulating layer and has a different composition from the first ceramic insulating layer. The ceramic laminated body characterized by the above-mentioned. 2. The ceramic laminate according to claim 1, wherein the first ceramic insulating layer is thicker than the second ceramic insulating layer. 2. The ceramic laminate according to claim 1, wherein the first ceramic insulating layer has a sintering start temperature higher than that of the second ceramic insulating layer.

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