JP2008159725A - Ceramic multi-layered substrate, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic multi-layered substrate having a high dimensional accuracy and a manufacturing method of the same which suppresses the warp or waviness of an insulating layer positioned between a cavity opened on the upper surface and another cavity opened on the lower surface while suppressing the generation of crack on the rims of bottom part of the cavities. <P>SOLUTION: The ceramic multi-layered substrate is constituted of laminates of first insulating layers, each having a cavity formation through hole penetrating into the laminating direction, which are laminated on the upper side and the lower side of a composite laminate 11, in which a first insulating layer 50 and a second insulating layer 51, having a calcination contraction finishing temperature lower than a calcination contraction starting temperature of the first insulating layer 50, are laminated alternately. Also, at least one part of a first cavity 101a or a cavity forming the through hole opened on the upper surface and a second cavity 101b or the cavity forming the through hole opened on the lower surface are superposed when seen from the upper side thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a ceramic multilayer substrate provided with a cavity opened on the upper surface and a cavity opened on the lower surface, and a method of manufacturing the same.

  In order to realize a package structure of an electronic component such as a semiconductor element, for example, a ceramic multilayer substrate provided with a cavity opened on an upper surface is used. According to this structure, an electronic component can be accommodated in the cavity, which can contribute to reducing the size and thickness of the electronic device.

  On the other hand, a shrinkage suppression layer containing inorganic material powder having a sintering temperature higher than that of the glass ceramic green sheet is formed on both the upper and lower surfaces of the green sheet laminate in which the glass ceramic green sheets are laminated, and the shrinkage suppression layer is sintered. Obtained by suppressing the shrinkage in the main surface direction (xy direction) of the green sheet by the method of peeling off and removing the unsintered inorganic material powder constituting the shrinkage suppression layer It is known that the dimensional accuracy of a substrate can be increased (see Patent Document 1).

  However, when this method is applied to the ceramic multilayer substrate provided with the cavity, there is a problem that the method warps toward the upper surface side where the cavity opens.

Therefore, it has been proposed to suppress warpage by using a composite laminate of a second shrinkage suppression layer having relatively low rigidity and a first shrinkage suppression layer having high rigidity as the shrinkage suppression layer. (See Patent Document 2).
Japanese Patent No. 2554415 JP 2002-151855 A

  Here, in order to achieve further miniaturization and thinning, the ceramic multilayer substrate may include a cavity opened on the upper surface and a cavity opened on the lower surface, and these cavities may partially overlap in a top view.

  In such a case, depending on the method described in Patent Document 1 and Patent Document 2 in which the shrinkage suppression layer is disposed only on the upper surface and the lower surface of the ceramic multilayer substrate, the first cavity and the second cavity Since the effect of suppressing the firing shrinkage cannot be given to the green sheet laminate (insulating layer) in between, the warp and undulation of this part (cavity bottom part) cannot be suppressed.

  The present invention has been made in view of the above circumstances, and a ceramic multilayer substrate with high dimensional accuracy in which warpage and undulation of an insulating layer located between a cavity opened on the upper surface and a cavity opened on the lower surface are suppressed, and the manufacture thereof It aims to provide a method.

  According to the present invention, the first insulating layer and the second insulating layer whose firing shrinkage end temperature is lower than the firing shrinkage start temperature of the first insulating layer are stacked on the upper and lower sides of the composite laminate. The first insulating layer having a cavity forming through-hole penetrating in the laminating direction is laminated, and the first cavity by the cavity forming through-hole opened on the upper surface and the cavity opened on the lower surface The second cavity formed by the formation through-hole is a ceramic multilayer substrate characterized in that at least a part thereof overlaps when viewed from above.

  Here, in the ceramic multilayer substrate, it is preferable that the first insulating layer is disposed in an uppermost layer and a lowermost layer of the composite laminate.

  The present invention also includes a step of preparing a first green sheet containing glass powder and ceramic powder, and the end of firing shrinkage from the firing shrinkage start temperature of the first green sheet containing glass powder and ceramic powder. A step of preparing a second green sheet having a low temperature, a step of preparing a firing shrinkage suppression green sheet having a firing shrinkage start temperature higher than a firing shrinkage end temperature of the first green sheet, and the first green sheet And a step of producing a composite green sheet laminate by alternately laminating the second green sheets, and cavity forming through holes penetrating in the laminating direction on the upper side and the lower side of the composite green sheet laminate, respectively. A first green sheet laminate in which a plurality of first green sheets having a plurality of layers are laminated, The cavity forming through holes of the first green sheet laminate on the lower side are arranged so that at least a part thereof overlaps in a top view, and the upper side and the lower side of the first green sheet laminate on the upper side Placing the fired shrinkage-suppressing green sheet on the lower side of the first green sheet laminate, and superimposing the stacked green sheet laminate, the first green sheet laminate, and the firing shrinkage. Removing the firing shrinkage-suppressing green sheet after firing the restraining green sheet at a temperature not lower than the firing shrinkage end temperature of the first green sheet and less than the firing shrinkage start temperature of the firing shrinkage-suppressing green sheet; A method for producing a ceramic multilayer substrate.

  The present invention also includes a step of preparing a first green sheet containing glass powder and ceramic powder, and the end of firing shrinkage from the firing shrinkage start temperature of the first green sheet containing glass powder and ceramic powder. A composite green sheet in which a step of preparing a second green sheet having a low temperature, a step of preparing a firing shrinkage suppression sheet that does not undergo firing shrinkage, and the first green sheet and the second green sheet are alternately laminated. A step of producing a laminate, and a first green sheet laminate in which a plurality of first green sheets each having a cavity-forming through-hole penetrating in the laminating direction are laminated on the upper and lower sides of the composite green sheet laminate. The cavity of each of the upper first green sheet laminate and the lower first green sheet laminate The formation through-hole is disposed so that at least a part thereof overlaps in a top view, and the firing shrinkage is further performed on the upper side and the lower side of the first green sheet laminate on the lower side. A step of arranging and superposing a suppression sheet, and superposing the composite green sheet laminate, the first green sheet laminate, and the firing shrinkage suppression sheet on the firing shrinkage end temperature of the first green sheet. And a step of removing the firing shrinkage-suppressing sheet after firing at a temperature.

  Here, in the method for manufacturing the ceramic multilayer substrate, it is preferable that first green sheets are disposed on the uppermost layer and the lowermost layer of the composite green sheet laminate.

  According to the ceramic multilayer substrate of the present invention, the first cavity opened on the upper surface and the second cavity opened on the lower surface are at least partially overlapped with each other when viewed from above, and the first insulating layer and the second cavity are interposed therebetween. Since the composite laminated body in which the second insulating layer having the firing shrinkage end temperature lower than the firing shrinkage start temperature of the first insulating layer is alternately provided is provided, the second insulating layer is formed. Until the firing shrinkage of the green sheet, the green sheet for forming the second insulating layer is suppressed from shrinking in the plane direction by the green sheet for forming the unsintered first insulating layer, When the green sheet for forming the insulating layer starts firing shrinkage, the green sheet for forming the first insulating layer is suppressed from shrinking in the planar direction by the already sintered second insulating layer. , The first The tee and the thickness of the thin portion between the second cavity (cavity bottom) can be inhibited from warping or waviness occurs, it is possible to sufficiently ensure the flatness.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of an embodiment of the ceramic multilayer substrate of the present invention. The ceramic multilayer substrate shown in FIG. 1 has a firing shrinkage start temperature of the first insulating layer 50 and the first insulating layer 50. Lamination of the first insulating layer having through holes for forming cavities penetrating in the laminating direction on the upper and lower sides of the composite laminated body 11 in which the second insulating layers 51 having low firing shrinkage temperatures are alternately laminated. The bodies 12 and 13 are laminated, and the first cavity 101a formed by the cavity forming through hole opened on the upper surface and the second cavity 101b formed by the cavity forming through hole opened on the lower surface are at least in a top view. It is characterized by a partial overlap.

  The first insulating layers 50 and the second insulating layers 51 constituting the composite laminate 11 are alternately laminated, and each is made of a ceramic sintered body. Examples of the ceramic sintered body include glass ceramics, alumina, mullite, and the like. Glass ceramics are preferable in that a low-resistance conductor such as gold, silver, or copper can be used as the wiring layer. Hereinafter, the case where the 1st insulating layer 50 and the 2nd insulating layer 51 are comprised with glass ceramic is demonstrated.

  The glass ceramics constituting the first insulating layer 50 and the glass ceramics constituting the second insulating layer 51 have different firing shrinkage start temperatures. Specifically, the firing shrinkage end temperature of the green sheet (second green sheet 202) for forming the second insulating layer 51 is equal to the green sheet (first green for forming the first insulating layer 50). In order to form the first insulating layer 50 after the completion of the firing shrinkage of the green sheet (second green sheet 202) for forming the second insulating layer 51 because the firing shrinkage starting temperature of the sheet 201) is lower. The green sheet (first green sheet 201) starts firing shrinkage.

  Here, the firing shrinkage start temperature is defined as the temperature at which the volume shrinks by 0.3% when the target material is fired alone. The term “firing shrinkage end temperature” as used herein refers to a temperature at which the shrinkage amount is 90% or more with respect to the shrinkage amount from the state before firing to the state after firing. The volume shrinkage is determined by TMA (thermomechanical analysis) by individually press-molding the inner restraint portion and the outer conductor portion. At this time, each contracts isotropically and is converted from volumetric shrinkage of TMA to volume shrinkage.

  Thus, when the green sheet (second green sheet 202) for forming the second insulating layer 51 starts firing shrinkage, the first insulating layer 50 that has not yet started firing shrinkage is formed. When the green sheet (first green sheet 201) for forming the first insulating layer 50 is restrained by the green sheet (first green sheet 201) to start firing contraction, it is already fired. Since it is restrained by the second insulating layer 51 that has finished shrinking, as a result, shrinkage in the XY direction due to firing is suppressed.

  The thickness of the second insulating layer 51 is preferably thinner than the thickness of the first insulating layer 50. When the second insulating layer 51 is thicker than the first insulating layer 50, the second cavity is formed when the green sheet (second green sheet 202) for forming the second insulating layer 51 is baked and contracted. This is because a tensile stress is generated at the corner that is the boundary between the bottom of 101b and the side surface of the second cavity 101b, and a crack may occur.

  On the upper side and the lower side of the composite laminate 11, laminates 12 and 13 are provided in which first insulating layers each having a cavity-forming through-hole penetrating in the laminating direction are laminated.

  The laminated body 12 of the first insulating layer and the laminated body 13 of the first insulating layer are configured by laminating insulating layers made of the same glass ceramics as the first insulating layer 50 constituting the composite laminated body 11. Thus, the cavity forming through-holes of the first insulating layer 50 are arranged coaxially so that the first cavity 101a is formed by the cavity forming through-holes opened on the upper surface and the cavity forming holes opened on the lower surface. A ceramic multilayer substrate having a second cavity 101b formed by a through hole is formed.

  The first cavity 101a and the second cavity 101b are at least partially overlapped when viewed from above, and the thickness between them is thin. In FIG. 1, the first cavity 101a and the second cavity 101b have the same diameter and are arranged on the same axis. However, in the present invention, these diameters are different or the central axis is shifted. Even if it is a case, the effect will be exhibited if at least one part has overlapped by the top view.

  That is, as will be described later, the upper side of the green sheet stack (first green sheet stack 22a) and the first insulating layer stack 13 for forming the first insulating layer stack 12 are formed. When a fired shrinkage-suppressing green sheet or a fired shrinkage-suppressing sheet is superimposed on the lower side of the green sheet laminate (first green sheet laminate 22b) for firing, the shrinkage-inhibiting effect of these sheets does not work. Second insulation having a firing shrinkage end temperature lower than the firing shrinkage start temperature of the green sheet for forming the first insulating layer 50 in the thin portion between the first cavity 101a and the second cavity 101b By disposing a green sheet for forming the layer 51, shrinkage in the XY direction is suppressed, and warping and undulation at the bottom of the cavity are suppressed. Can. This is particularly effective when the thickness of the composite laminate 11 is 0.4 mm or less.

  In the drawing, the surface layer wiring conductor 71 and the inner layer wiring conductor 72 made of Cu, Ag, Au, Pt, Pd, etc., and the surface layer wiring conductor 71 and the inner layer wiring conductor 72 and the inner layer wiring conductor 72 formed in each layer are electrically connected. The via hole conductor 73 to be connected is shown. Circuit elements such as capacitors, inductors or resistors may be provided by the surface layer wiring conductor 71, the inner layer wiring conductor 72, the via hole conductor 73, and the like. Although not shown, passive components such as capacitors or inductors are prepared in the form of blocks, and such block components may be incorporated.

  FIG. 2 is a schematic cross-sectional view of another embodiment of the ceramic multilayer substrate of the present invention, and includes a composite laminate 11 having a configuration different from that of the composite laminate 11 shown in FIG. In the configuration shown in FIG. 1, the first insulating layer 50 is disposed at the bottom of the first cavity 101a, and the second insulating layer 51 is disposed at the bottom of the second cavity 101b. 2, the first insulating layer is disposed on the uppermost layer of the composite laminate 11 that is the bottom of the first cavity 101a and the lowermost layer of the composite laminate 11 that is the bottom of the second cavity 101b. It is what.

  According to this configuration, the start of firing shrinkage of the first green sheet 201 to be the first insulating layer 50 is after the end of firing shrinkage of the second green sheet 202 to be the second insulating layer 51. In addition, the carbon content remaining in the insulating layer during the firing process can be effectively removed from the system, so that the insulating layer can be prevented from peeling off or expanding due to the volatilization of the carbon inside the insulating layer at the final stage of firing. In addition, there is an advantage that a high yield with good electrical characteristics can be obtained. Furthermore, since the bottoms of the first cavity 101a and the second cavity 101b are made of the same material as the first insulating layer 50, the mutual adhesiveness is high, and the mechanical reliability of the substrate can be improved.

  In addition, the first insulating layer stack 12 and the first insulating layer stack 13 are only the first insulating layer 50 and not different materials, so that different materials can be bonded. The problem of residual stress generated after firing at the interface can be reduced and the mechanical reliability of the ceramic multilayer substrate can be improved. However, in the case where too many layers are laminated, in order to enhance the shrinkage suppression effect, as shown in FIG. As described above, the second insulating layer 51 may be disposed on the first insulating layer stack 12 and the first insulating layer stack 13.

  Next, a method for manufacturing the ceramic multilayer substrate shown in FIG. 2 will be described based on the explanatory view shown in FIG.

  First, a first green sheet 201 that becomes the first insulating layer 50 after firing is prepared, and a second green sheet 202 that becomes the second insulating layer 51 after firing is prepared. The second green sheet 202 has a firing shrinkage end temperature lower than the firing shrinkage start temperature of the first green sheet 201.

  The first green sheet 201 is an insulating material that is the main component of the ceramic multilayer substrate. Therefore, in order to satisfy desired properties, the green sheet contains various ceramic powders such as alumina, silica, barium titanate, calcium titanate, zirconia, and zirconium titanate in addition to the glass powder.

  On the other hand, it is necessary to complete the sintering of the second green sheet 202 before the first green sheet 201 starts shrinkage due to firing. Therefore, the glass powder used for the first green sheet 201 has a different composition, and it is preferable to increase the glass content as compared with the green sheet 201 in order to further promote the shrinkage of the green sheet composition itself. As will be described later, the second green sheet 202 is formed thinner than the first green sheet 201, which is the main component of the ceramic multilayer substrate, but the first green sheet 201 is fired in the plane direction even when it is thin. In order to effectively suppress shrinkage, the glass itself is also preferably crystalline. In order to increase the rigidity in the firing process by crystal precipitation, it is necessary to improve the degree of crystallinity, but on the other hand, the problem of remaining voids accompanying crystallization also occurs, so it matches the composition of the first green sheet 201. It is important to select the second green sheet composition.

  The first green sheet 201 and the second green sheet 202 are made of a low-temperature sintered ceramic material. Specifically, a slurry is prepared by mixing glass powder with ceramic powder and dispersing this in an organic binder. The slurry is formed into a sheet shape.

The glass powder contained in the first green sheet 201 and the second green sheet 202 is mainly composed of B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ , MgO, and BaO. As a difference from the green sheet 202, the composition ratio of the glass powder is adjusted in order to adjust the thermal characteristics such as the softening temperature and the crystallization temperature. As the ceramic powder, alumina is mainly used. However, as described above, in order to improve the crystallinity of the second green sheet 202, it is used in combination with calcium zirconate as a crystal nucleation material.

  Specifically, glass powder with an average particle size of 1.8 μm and alumina with 1.4 μm are used for the first green sheet. On the other hand, as the second green sheet, 1.4 μm alumina powder and 0.6 μm calcium zirconate are applied to glass powder having a composition ratio different from that of the first green sheet and having an average particle diameter of 1.8 μm.

  In view of the tensile stress and the like described above, the thickness of the second green sheet 202 is preferably thinner than the thickness of the first green sheet 201. In order to obtain a desired thickness, a plurality of thin green sheets are used. The thicknesses of the first green sheet 201 and the second green sheet 202 are adjusted again.

  Next, the 1st green sheet 201 and the 2nd green sheet 202 are laminated | stacked alternately, and the composite green sheet laminated body 21 is produced. This composite green sheet laminate 21 becomes the composite laminate 11 shown in FIG. 2 after firing.

  The composite green sheet laminate 21 is formed by alternately laminating the first green sheets 201 and the second green sheets 202. Instead of this method, the second insulating layer 51 includes: A slurry containing ceramic powder and glass powder may be formed by applying printing or the like on the first green sheet 201.

  Also, a plurality of first green sheets 201 are laminated to produce first green sheet laminates 22a and 22b. Each of the first green sheets 201 constituting the first green sheet laminates 22a and 22b has a cavity forming through-hole penetrating in the laminating direction, which is coaxially arranged to form a cavity as a whole. Through holes 102a and 102b are formed. The first green sheet laminates 22a and 22b become the first insulation layer laminates 12 and 13 shown in FIG. 2 after firing. Here, the cavity forming through holes 102a and 102b are preferably formed by punching or cutting after a plurality of first green sheets are laminated to produce the first green sheet laminates 22a and 22b.

  On the other hand, firing shrinkage suppression green sheets 203a and 203b having a firing shrinkage start temperature higher than the firing shrinkage end temperature of the first green sheet 201 are prepared. These firing shrinkage-suppressing green sheets 203a and 203b are provided on the upper side of the first green sheet laminate 22a in order to suppress shrinkage in the XY direction during firing of the first green sheet laminates 22a and 22b described later. These are disposed below the first green sheet laminate 22b and are removed after firing the composite green sheet laminate 21 and the first green sheet laminates 22a and 22b. The firing shrinkage-suppressing green sheets 203a and 203b are mainly composed of ceramic powder that does not sinter at the firing temperature of the ceramic multilayer substrate. Specifically, alumina is used, but alumina that is versatile and inexpensive is most suitable. Furthermore, in order to increase the affinity with the firing shrinkage-suppressing green sheet in the firing process of the ceramic multilayer substrate, the glass powder contained in the first green sheet may be contained in the range of 20% by weight or less. Thereby, the shrinkage suppression effect is further enhanced, and a ceramic multilayer substrate with higher dimensional accuracy can be obtained.

  And while arrange | positioning the 1st green sheet laminated body 22a on the upper side of the composite green sheet laminated body 21, and arrange | positioning the 1st green sheet laminated body 22b on the lower side of the composite green sheet laminated body 21, these are overlap | superposed. . At this time, at least a part of the cavity forming through hole 102a of the upper first green sheet laminate 22a and the cavity forming through hole 102b of the lower first green sheet laminate 22b overlap each other in a top view. Arrange as follows. In the case of such an arrangement, the effect of the present invention is exhibited.

  Further, the firing shrinkage suppression green sheet 203a is disposed on the upper side of the upper first green sheet laminate 22a, and the firing shrinkage suppression green sheet 203b is disposed on the lower side of the lower first green sheet laminate 22b. Superimpose these. Here, through-holes 103a and 103b are also formed in the firing shrinkage-suppressing green sheets 203a and 203b, the through-holes 103a are arranged coaxially with the cavity-forming through-holes 102a, and the through-holes 103b are formed through the cavity-forming through holes. It is preferable to be arranged coaxially with the hole 102b. In order to form and arrange in this way, as shown in FIG. 4, the first green sheet laminates 22a and 22b and the fired shrinkage green sheets 203a and 203b are preliminarily superposed, and the superposed first The through-holes 102a and 102b for forming cavities and the through-holes 103a and 103b are preferably formed by punching or cutting the green sheet laminates 22a and 22b and the fired and shrunken green sheets 203a and 203b.

  When the composite green sheet laminate 21, the first green sheet laminates 22a and 22b, and the fired shrinkage-suppressing green sheets 203a and 203b are overlapped and integrated, the peripheral portions of the cavity forming through holes 102a and 102b It is preferable that the first green sheet laminate 22a, 22b is pressed and the composite green sheet laminate 21 is pressed through the cavity forming through holes 102a, 102b. Specifically, the composite laminate 21, the first green sheet laminates 22a and 22b, and the firing shrinkage-suppressing green sheets 203a and 203b are aligned by image recognition, and a rigid press method or an isostatic press method is applied.

  At this time, the first green sheet laminates 22a and 22b, which are peripheral portions of the cavity forming through holes 102a and 102b, and the composite green sheet laminate 21 exposed through the cavity forming through holes 102a and 102b are mutually the same. It is preferable to press in the stacking direction so as to apply pressure.

  For example, in the case of the rigid body pressing method, a press device configured to apply the same pressure to each part independently at the same time may be used, but each part is divided into two stages with a time difference and the same pressure is applied. You may use the press apparatus comprised so that it might apply.

  Further, in the case of the isostatic pressing method, it is easy to apply the same pressure all at once, and it can be suitably used for pressing a laminate having a cavity according to the present invention.

  As shown in the figure, the composite green sheet sheet laminate 21, the first green sheet laminates 22a and 22b, and the shrinkage-suppressing green sheets 203a and 203b are integrated at the interface of each sheet. A paste 710 for the surface layer wiring conductor that becomes the surface layer wiring conductor 71 after baking, and a paste 720 for the inner layer wiring conductor that becomes the inner layer wiring conductor 72 after baking are applied, and the first green sheet 201 and the second green sheet 202 are applied. A via-hole conductor paste 730 is filled so as to penetrate therethrough.

  And it transfers to the baking process which bakes the composite green sheet laminated body 21, the 1st green sheet laminated body 22a, 22b and the baking shrinkage | contraction suppression green sheet 203a, 203b which were piled up. Specifically, a degreasing process for decomposing and eliminating organic components is performed, and then a main baking process is performed.

  In this main firing step, the first green sheet 201 and the second green sheet 202 and the second green sheet 202 are separately maintained by changing the rate of temperature rise, or separately holding at an intermediate temperature from degreasing to main firing in addition to maintaining the main firing temperature. The first green sheet 201 and the fired shrinkage-suppressing green sheets 203a and 203b can increase the binding force of each other and reduce warpage and undulation.

  It is important that the firing temperature at this time is equal to or higher than the firing shrinkage end temperature of the first green sheet 201 and lower than the firing shrinkage start temperature of the firing shrinkage suppression green sheets 203a and 203b. In order to suppress the firing shrinkage of the first green sheet 201, the temperature of the first green sheet 201 is higher than the temperature at which the firing shrinkage is finished and the firing shrinkage suppression green sheets 203a and 203b start firing shrinkage ( It is important to fire at a temperature below (sintering). When the fired shrinkage-suppressing green sheets 203a and 203b are densified, they cannot be peeled after firing. Therefore, firing within the above range is necessary.

  As in this embodiment, the shapes of the through portions 103a and 103b provided in the firing shrinkage suppressing green sheets 203a and 203b are substantially the same as the opening shapes of the through holes 102a and 102b of the first green sheet laminates 22a and 22b. In this case, the surfaces of the first green sheet laminates 22a and 22b are completely covered, and the restraining force for suppressing the firing shrinkage by the firing shrinkage suppression sheets 203a and 203b in the firing step is applied to the through holes 102a and 102b. The ceramic multilayer substrate can be formed with high dimensional accuracy, and deformation and cracks in the peripheral portions of the first cavity and the second cavity after firing are eliminated. In addition, since the composite green sheet laminate 21 is made of the first green sheet 201 and the second green sheet 202, after firing, the first green sheet 201 and the second green sheet 202 are disposed between the first cavity 101a and the second cavity 101b. Warpage and undulation can be suppressed from occurring in a thin portion (cavity bottom), and sufficient flatness can be ensured.

  After the firing process is completed in this manner, the unsintered fired shrinkage-suppressing green sheets 203a and 203b remaining on the upper and lower surfaces of the fired ceramic multilayer substrate are usually removed by a technique such as blasting.

  Heretofore, the use of the firing shrinkage suppression green sheet has been described, but instead of the firing shrinkage suppression green sheet, a firing shrinkage suppression sheet that does not undergo firing shrinkage can also be employed. The term “not shrinkage by firing” means, for example, that the material has already been sintered and no longer shrinks by firing. As a firing shrinkage suppression sheet, an alumina sintered body, a low-temperature sintered substrate having a high degree of crystallinity of 99% or more and a low residual glass, Examples thereof include a silicon nitride sintered body, a silicon nitride sintered body, carbon, and a tungsten sintered body that are excellent in thermal conductivity. This fired shrinkage suppression sheet is bonded to the first green sheet laminates 22a and 22b using a viscous member such as an acrylic resin having excellent thermal decomposability, so that the X− of the first green sheet laminates 22a and 22b. Firing shrinkage in the Y direction can be suppressed. In this case, the firing temperature can be fired at a temperature at which the first green sheet is sintered as described above. Moreover, when using an alumina sintered compact, there is no restriction | limiting in the baking atmosphere. However, when a silicon nitride sintered body or a silicon nitride sintered body is used, it is limited to firing in a neutral atmosphere or a reducing atmosphere.

It is a schematic sectional drawing of one Embodiment of the ceramic multilayer substrate of this invention. It is a schematic sectional drawing of other embodiment of the ceramic multilayer substrate of this invention. It is a schematic sectional drawing of other embodiment of the ceramic multilayer substrate of this invention. It is explanatory drawing of the manufacturing method of the ceramic multilayer substrate shown in FIG.

Explanation of symbols

50 ... 1st insulating layer 51 ... 2nd insulating layer 11 ... Composite laminated body 12, 13 ... Laminated body 101a of 1st insulating layer ... 1st cavity 101b ... Second cavity 71: Surface layer wiring conductor 72 ... Inner layer wiring conductor 73 ... Via hole conductor 201 ... First green sheet 202 ... Second green sheet 21 ... Composite green sheet Laminated bodies 22a, 22b ... first green sheet laminated bodies 203a, 203b ... firing shrinkage suppression green sheets (firing shrinkage suppression sheets)
710 ... Surface layer wiring conductor paste 720 ... Inner layer wiring conductor paste 730 ... Via hole conductor paste

Claims (5)

The first insulating layer and the stacking direction on the upper side and the lower side of the composite laminate in which the second insulating layer whose firing shrinkage end temperature is lower than the firing shrinkage start temperature of the first insulating layer are alternately laminated. A first insulating layer stack having a cavity-forming through-hole penetrating into the first cavity and the cavity-forming through-hole opening in the lower surface and the first cavity formed by the cavity-forming through-hole opening in the upper surface; A ceramic multilayer substrate characterized in that at least a part of the second cavity is overlapped in a top view. The ceramic multilayer substrate according to claim 1, wherein the first insulating layer is disposed on an uppermost layer and a lowermost layer of the composite laminate. Preparing a first green sheet containing glass powder and ceramic powder;
Preparing a second green sheet containing glass powder and ceramic powder and having a firing shrinkage end temperature lower than the firing shrinkage start temperature of the first green sheet;
Preparing a firing shrinkage suppression green sheet having a firing shrinkage start temperature higher than a firing shrinkage end temperature of the first green sheet;
Producing a composite green sheet laminate by alternately laminating the first green sheets and the second green sheets;
A first green sheet laminate in which a plurality of first green sheets each having a cavity-forming through-hole penetrating in the laminating direction is laminated on the upper and lower sides of the composite green sheet laminate, Each of the green sheet laminate and the lower first green sheet laminate is disposed so that at least a part thereof overlaps in the top view, and the upper first green sheet laminate Disposing and overlapping the firing shrinkage-suppressing green sheet on the lower side of the first green sheet laminate on the upper and lower sides of the body;
The composite green sheet laminate, the first green sheet laminate, and the firing shrinkage-suppressing green sheet that are superposed are equal to or higher than the firing shrinkage end temperature of the first green sheet, and And a step of removing the firing shrinkage-suppressing green sheet after firing at a temperature lower than the firing shrinkage start temperature. Preparing a first green sheet containing glass powder and ceramic powder;
Preparing a second green sheet containing glass powder and ceramic powder and having a firing shrinkage end temperature lower than the firing shrinkage start temperature of the first green sheet;
A step of preparing a firing shrinkage suppression sheet that does not undergo firing shrinkage;
Producing a composite green sheet laminate by alternately laminating the first green sheets and the second green sheets;
A first green sheet laminate in which a plurality of first green sheets each having a cavity-forming through-hole penetrating in the laminating direction is laminated on the upper and lower sides of the composite green sheet laminate, Each of the green sheet laminate and the lower first green sheet laminate is disposed so that at least a part thereof overlaps in the top view, and the upper first green sheet laminate Placing and stacking the firing shrinkage suppression sheet on the lower side of the first green sheet laminate on the upper side and lower side of the body;
After firing the composite green sheet laminate, the first green sheet laminate, and the firing shrinkage suppression sheet superposed on each other at the firing shrinkage end temperature of the first green sheet, the firing shrinkage suppression sheet And a step for removing the ceramic multilayer substrate. 5. The method for producing a ceramic multilayer substrate according to claim 3, wherein a first green sheet is disposed in an uppermost layer and a lowermost layer of the composite green sheet laminate.

Images