JP4599706B2 - Manufacturing method of multilayer ceramic substrate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a multilayer ceramic substrate, for example, a method for manufacturing a multilayer ceramic substrate having a cavity for mounting and accommodating an electronic component.
[0002]
[Prior art]
In recent years, there has been a growing demand for electronic devices that are smaller, lighter, more multifunctional, and more reliable, and in response to this, improvements in mounting technology on substrates have also been demanded. As an effective method for improving the technology for mounting on a substrate, the most typical method is to increase the density of wiring on the substrate.
[0003]
Therefore, in order to cope with the higher density of wiring on such a substrate, a multilayer ceramic substrate manufactured by stacking, pressing, and firing a plurality of ceramic green sheets formed by printing a conductor film or the like Development is underway. However, in order to proceed with higher density of wiring on the multilayer ceramic substrate without any problem, in the stage of firing the green sheet laminate obtained by laminating a plurality of ceramic green sheets, the ceramic green sheet or firing it is performed. Therefore, precise control technology is required for the dimensions and shape of the ceramic layer obtained in this way.
[0004]
As a method for enabling this, Japanese Patent No. 2554415 discloses that the upper and lower surfaces of a green sheet laminate in which glass ceramic green sheets are laminated contain inorganic material powder having a sintering temperature higher than that of the glass ceramic green sheets. A method of peeling and removing the unsintered inorganic material powder constituting the shrinkage suppression layer after forming, pressing, and firing the layer is disclosed, and Japanese Patent No. 2617643 discloses the method described above. A method is further disclosed in which pressure is further applied from above and below the green sheet laminate.
[0005]
According to these methods, since shrinkage hardly occurs in the main surface direction of the green sheet, that is, the xy direction, the dimensional accuracy of the obtained substrate can be increased, and high density wiring can be achieved with high reliability. Can do.
[0006]
On the other hand, in the multilayer ceramic substrate, in addition to the above-described improvement in dimensional accuracy, higher density of wiring, and higher reliability, it is required to reduce the size and height of itself. In order to realize these, it is effective to form a cavity for mounting electronic components on a multilayer ceramic substrate.
[0007]
However, in the case of a multilayer ceramic substrate in which such cavities are formed, warping and undulation such that the end surface side where the openings of the cavities are located in a concave shape are likely to occur in the firing step for obtaining them.
[0008]
In order to solve this problem, Japanese Patent Application Laid-Open No. 9-202665 discloses that in the firing step, a load body is partially placed on the green sheet laminate to be a multilayer ceramic substrate having a cavity, or inside the cavity. There is described a method for manufacturing a multilayer ceramic substrate in which a load body smaller than the cavity is placed and warpage and undulation are unlikely to occur.
[0009]
[Problems to be solved by the invention]
However, if the method described in Japanese Patent No. 2617643 or Japanese Patent Laid-Open No. 9-202665 is to be carried out, it is necessary to fire while applying a relatively large pressure to the green sheet laminate to be fired. Therefore, special equipment capable of such pressure firing is required, and there are problems in terms of equipment cost and production efficiency.
[0010]
Further, in recent years, in a multilayer ceramic substrate, the number of input / output terminals for mounting on a motherboard and for electrical connection has increased dramatically as the wiring density becomes higher. In addition, with the increase in functionality and performance, it is necessary to arrange a large number of circuit elements with high precision, and it is also necessary to incorporate circuit elements such as capacitors and inductors at high density. Has been.
[0011]
In particular, under the circumstances as described above, a relatively large difference in the degree of shrinkage tends to occur between the one end face side and the other end face side of the green sheet laminate. If pressure is not applied, there is a high possibility that warping will occur.
[0012]
The present invention has been made in view of the above-described problems, and in the method for manufacturing a multilayer ceramic substrate having a cavity, it is possible to suppress shrinkage in the xy direction and warp without being particularly pressurized during firing. The purpose is to make it difficult to produce undulations.
[0013]
[Means for Solving the Problems]
The invention includes a step of preparing a ceramic material powder containing a glass component, a step of preparing an inorganic material powder for shrinkage suppression having a sintering temperature higher than that of the ceramic material powder, Forming a first glass-ceramic green sheet having a through-hole for forming a second glass-ceramic green sheet having no through-hole at least at the position of the above-mentioned through-hole, and a first glass By laminating the ceramic green sheet and the second glass ceramic green sheet, to obtain a green sheet laminate having a cavity formed by a through-hole so as to position the opening in the first end face in the lamination direction, The 1st end surface of this green sheet laminated body and the 2nd end facing the 1st end surface Are provided with first and second shrinkage suppression layers containing the inorganic material powder for shrinkage suppression, whereby the first and second end faces of the green sheet laminate are the first and second shrinkage suppression layers. A step of obtaining a composite laminate each covered by a step, a step of pressing the composite laminate in the laminating direction, and In a state where no load is applied in the stacking direction of the composite laminate, The present invention is directed to a method for manufacturing a multilayer ceramic substrate including a step of firing a composite laminate, and is characterized by having the following configuration in order to solve the technical problems described above.
[0014]
That is, the present invention provides the above composite laminate, The first shrinkage suppression layer has a through-hole exposing the opening of the cavity; and The first shrinkage suppression layer is characterized by having higher rigidity than the second shrinkage suppression layer.
[0015]
As described above, in order to make the rigidity of the first shrinkage suppression layer higher than that of the second shrinkage suppression layer, there are various embodiments within the scope of the present invention.
[0016]
In the first embodiment, the first shrinkage suppression layer is thicker than the second shrinkage suppression layer.
[0017]
In the second embodiment, the average particle size of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer is made smaller than the average particle size of the inorganic material powder for shrinkage suppression contained in the second shrinkage suppression layer. The
[0018]
In the third embodiment, when the first and second shrinkage suppression layers include an organic binder, the amount of the organic binder contained in the first shrinkage suppression layer is the amount of the organic binder contained in the second shrinkage suppression layer. Less than the amount.
[0019]
In the fourth embodiment, the first shrinkage suppression layer includes fiber-like inorganic oxide particles.
[0020]
In the fifth embodiment, the first shrinkage suppression layer includes glass powder that does not cause viscous flow under the firing conditions in the firing step described above.
[0021]
The first to fifth embodiments described above may be implemented in a state where some of these are combined.
[0022]
In the present invention, the first and second shrinkage suppression layers provided in the composite laminate described above are prepared in a green sheet state, and the composite laminate is manufactured by laminating the first and second shrinkage suppression layers on the green sheet laminate. It is preferable. That is, in the step of obtaining a composite laminate, the first and second shrinkage suppression layers are produced by forming a slurry in which an inorganic material powder for shrinkage suppression is dispersed in an organic binder into a sheet shape. It is preferable to provide a step of laminating these first and second inorganic material green sheets respectively along the first and second end faces of the green sheet laminate, respectively, as second inorganic material green sheets. .
[0023]
In the step of firing the composite laminate, a firing temperature of 1000 ° C. or lower is preferably applied.
[0026]
Moreover, in this invention, since the 1st shrinkage | contraction suppression layer has a penetration part which exposes the opening of a cavity, In the step of pressing the composite laminate, preferably, the peripheral portion of the cavity is pressed and the bottom surface portion of the cavity is pressed through the penetration portion.
[0027]
In addition, after the step of firing the composite laminate, the first and second shrinkage suppression layers are usually removed.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 schematically shows a cross-sectional view of a composite laminate 1 obtained in the middle of manufacturing a multilayer ceramic substrate by carrying out the manufacturing method according to one embodiment of the present invention.
[0029]
In order to obtain such a composite laminate 1, a low-temperature sintered ceramic material powder containing a glass component is prepared, and an inorganic material powder for shrinkage suppression having a sintering temperature higher than that of the low-temperature sintered ceramic material powder is prepared. Is done.
[0030]
Also, the first glass ceramic green sheet 4 having the through hole 3 for forming the cavity 2 and the second glass ceramic green sheet 5 having no through hole, which contain the above-mentioned low-temperature sintered ceramic material powder, Are produced respectively.
[0031]
And the green sheet laminated body 6 is obtained by laminating | stacking the 1st glass ceramic green sheet 4 and the 2nd glass ceramic green sheet 5. FIG. More specifically, in order to obtain the green sheet laminate 6, a plurality of first glass ceramic green sheets 4 are laminated on a laminate of a plurality of second glass ceramic green sheets 5. Therefore, of the first and second end faces 7 and 8 facing each other in the stacking direction of the green sheet laminate 6, the opening 9 of the cavity 2 formed by the through hole 3 is located on the first end face 7. is doing.
[0032]
Although not shown, the green sheet laminate 6 has an internal conductor film formed along a specific interface between the glass ceramic green sheets 4 and 5, or a specific one of the glass ceramic green sheets 4 and 5. Via hole conductors are formed so as to penetrate the outer surface, or external conductor films are formed on the end faces 7 and 8. A circuit element such as a capacitor, an inductor, or a resistor may be provided by a part of the inner conductor film, the via hole conductor, and the outer conductor film. In addition, passive components such as capacitors or inductors are prepared in the form of blocks, and such block components may be built in the green sheet laminate 6.
[0033]
Along with each of the first and second end faces 7 and 8 in the stacking direction of the green sheet laminate 6, the first and second shrinkage suppression layers 10 and 11 containing the above-described shrinkage suppression inorganic material powder are provided. Each is provided. Among these shrinkage suppression layers 10 and 11, in the first shrinkage suppression layer 10 along the first end surface 7 where the opening 9 of the cavity 2 is located, the through portion 12 that exposes the opening 9 of the cavity 2. It is preferable to be provided in a state having More preferably, the through portion 12 has substantially the same shape as the opening 9 of the cavity 2 as shown in FIG.
[0034]
The first and second shrinkage suppression layers 10 and 11 described above are prepared by, for example, preparing a slurry in which an inorganic material powder for shrinkage suppression is dispersed in an organic binder and molding the slurry into a sheet shape. And second inorganic material green sheets 13 and 14 respectively, and laminating these first and second inorganic material green sheets 13 and 14 together with the first and second glass ceramic green sheets 4 and 5. The green sheet laminate 6 can be provided along the first and second end faces 7 and 8, respectively.
[0035]
In each of the first and second shrinkage suppression layers 10 and 11, as will be described later, the first and second shrinkage suppression layers 10 and 11 that constitute each of the first and second shrinkage suppression layers 10 and 11 are obtained in order to obtain a necessary thickness. And the number of each of the second inorganic material green sheets 13 and 14 is adjusted.
[0036]
In place of the above-described method, the first and second shrinkage suppression layers 10 and 11 are made of a slurry containing an inorganic material powder for shrinkage suppression on the first and second end faces 7 and 8 of the green sheet laminate 6. Each may be formed by applying printing or the like.
[0037]
In this way, the composite laminate 1 is obtained in which the first and second end faces 7 and 8 of the green sheet laminate 6 are covered with the first and second shrinkage suppression layers 10 and 11, respectively.
[0038]
Next, the composite laminate 1 is pressed in the lamination direction. In this pressing step, preferably, the peripheral portion of the cavity 2 is pressed and the bottom surface portion of the cavity 2 is pressed through the through-hole 12. More specifically, the composite laminate 1 is pressed by placing the composite laminate 1 in a mold (not shown) and applying a hydrostatic press method or a rigid press method. .
[0039]
In this case, it is preferable to press the composite laminate 1 in the stacking direction so that the same pressure is applied to the bottom surface of the cavity 2 and the peripheral portion of the cavity 2. Therefore, it is preferable to use a mold having a structure that can apply pressure to the bottom surface of the cavity 2 and the peripheral portion of the cavity 2 independently of each other as the mold for housing the composite laminate 1.
[0040]
Further, the hydrostatic press method described above is more suitable than the rigid press method because it is easy to apply the same pressure to the bottom surface portion of the cavity 2 and the peripheral portion of the cavity 2 at a time in the pressing step. It is.
[0041]
In the case of the rigid body pressing method, a pressing device configured to apply the same pressure to the bottom surface portion of the cavity 2 and the peripheral portion of the cavity 2 may be used, but pressure is applied to the bottom surface portion of the cavity 2. The pressing process may be performed in two stages, namely, a step of applying pressure and a step of applying pressure to the periphery of the cavity 2.
[0042]
As in this embodiment, when the penetrating portion 12 of the first shrinkage suppression layer 10 has substantially the same shape as the opening 9 of the cavity 2, in the above-described pressing step, over the entire bottom surface portion of the cavity 2, It becomes easy to apply a uniform pressure.
[0043]
Next, the composite laminate 1 is fired. More specifically, in a normal oxidizing atmosphere, first, a degreasing process for decomposing and disappearing organic components contained in the composite laminate 1 is performed, and further a main firing process is performed. In the degreasing step, a temperature of about 200 to 600 ° C. is preferably applied, and in the main baking step, a temperature of about 800 to 1000 ° C. is preferably applied. In this firing step, the composite laminate 1 is fired without applying a load in the laminating direction.
[0044]
In the firing step described above, the shrinkage-suppressing inorganic material powder contained in the shrinkage-suppressing layers 10 and 11 is not substantially sintered, so that the shrinkage-suppressing layers 10 and 11 are not substantially shrunk. Therefore, in the green sheet laminate 6, shrinkage occurs only in the thickness direction in the firing step, and shrinkage in the xy direction is constrained by the shrinkage suppression layers 10 and 11, so that it does not substantially occur. Can be.
[0045]
Further, the end faces 7 and 8 of the green sheet laminate 6 are respectively covered with the shrinkage suppression layers 10 and 11, and the peripheral portion and the bottom portion of the cavity 2 in the composite laminate 1 are pressed before firing. Therefore, in the firing step, flatness at the bottom surface portion of the cavity 2 is ensured, and deformation and cracking of the peripheral portion of the cavity 2 can be suppressed.
[0046]
In addition, since the shrinkage | contraction suppression layer is not formed in the bottom face part of the cavity 2 in the composite laminated body 1, the force which shrink | contracts to an xy direction acts on this part, and, thereby, the cavity 2 in the composite laminated body 1 The entire composite laminate 1 is warped so that the end face on the opening 9 side is concave. However, if the rigidity of the first shrinkage suppression layer 10 is made higher than the rigidity of the second shrinkage suppression layer 11, the warpage of the composite laminate 1 as a whole can be suppressed.
[0047]
In this embodiment, as described above, since the difference in rigidity is given between the first shrinkage suppression layer 10 and the second shrinkage suppression layer 11, the first shrinkage suppression layer 10 has the second shrinkage suppression. It is made thicker than layer 11. As described above, the first and second shrinkage suppression layers 10 and 11 are composed of the first and second inorganic material green sheets 13 and 14, respectively. The number of stacked first inorganic material green sheets 13 constituting the first shrinkage suppression layer 10 and the number of stacked second inorganic material green sheets 14 constituting the second shrinkage suppression layer 11 are different from each other. The number of stacked first inorganic material green sheets 13 is made larger than the number of stacked second inorganic material green sheets 14.
[0048]
In the case where the first shrinkage suppression layer 10 is thicker than the second shrinkage suppression layer 11, the thickness of the first shrinkage suppression layer 10 is not more than three times the thickness of the second shrinkage suppression layer 11. It is preferable. When the thickness of the first shrinkage suppression layer 10 exceeds three times the thickness of the second shrinkage suppression layer 11, the thickness of the first shrinkage suppression layer 10 becomes unnecessarily thick. This is not preferable because the number of the first inorganic material green sheets 13 to be reduced or the number of the lamination processes increases.
[0049]
Moreover, setting the thickness of the first shrinkage suppression layer 10 to be three times or less the thickness of the second shrinkage suppression layer 11 in other words means that the thickness of the second shrinkage suppression layer 11 is the first shrinkage suppression layer 10. It is to make it 1/3 times or more of the thickness of. When the thickness of the second shrinkage suppression layer 11 is less than 1/3 times the thickness of the first shrinkage suppression layer 10, the thickness of the second shrinkage suppression layer 11 becomes too thin, and the shrinkage suppression effect as described above. May not be sufficiently exhibited, which is not preferable.
[0050]
As in this embodiment, when the penetrating portion 12 provided in the first shrinkage suppression layer 10 has substantially the same shape as the opening 9 of the cavity 2, the first shrinkage suppression layer 10 is around the cavity 2. The part is completely covered, and the restraining force for suppressing the shrinkage by the first shrinkage suppression layer 10 in the firing process can be exerted over the entire peripheral part of the cavity 2, and the deformation or cracking in the peripheral part of the cavity 2 It is possible to make the effect of suppressing the image more perfect.
[0051]
As described above, the target multilayer ceramic substrate can be obtained in an appropriate state by firing the composite laminate 1. After the multilayer ceramic substrate is obtained in this manner, the first and second shrinkage suppression layers 10 and 11 are usually removed.
[0052]
FIG. 2 is a cross-sectional view schematically showing a composite laminate 21 obtained in the middle of manufacturing a multilayer ceramic substrate by performing a manufacturing method according to another embodiment of the present invention. In FIG. 2, elements corresponding to those shown in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.
[0053]
A composite laminate 21 shown in FIG. 2 is used to obtain a multilayer ceramic substrate having a plurality of cavities 22, for example, two tiers, and is a first glass ceramic green having through holes laminated in a green sheet laminate 23. As the sheet, a glass ceramic green sheet 25 having a relatively large through hole 24 and a glass ceramic green sheet 27 having a relatively small through hole 26 are used.
[0054]
Also in this embodiment, the first and second shrinkage suppression layers 10 and 11 are provided along the first and second end faces 7 and 8 in the stacking direction of the green sheet laminate 23, respectively. The first shrinkage suppression layer 10 is thicker than the second shrinkage suppression layer 11.
[0055]
FIG. 3 is a cross-sectional view schematically showing a composite laminate 31 obtained in the course of manufacturing a multilayer ceramic substrate by carrying out a manufacturing method according to still another embodiment of the present invention. In FIG. 3, elements corresponding to those shown in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.
[0056]
The first and second shrinkage suppression layers 32 and 33 included in the composite laminate 31 shown in FIG. 3 have the same thickness. That is, the first and second shrinkage suppression layers 32 and 33 are respectively composed of the first and second inorganic material green sheets 34 and 35. For example, the first and second inorganic material green sheets If 34 and 35 have the same thickness, the first and second inorganic material green sheets 34 and 35 are stacked with the same number of layers.
[0057]
In this embodiment, in order to make the rigidity of the first shrinkage suppression layer 32 higher than the rigidity of the second shrinkage suppression layer 33, the shrinkage contained in the first shrinkage suppression layer 32, that is, the first inorganic material green sheet 34. The average particle size of the inorganic material powder for suppression is made smaller than the average particle size of the inorganic material powder for shrinkage suppression contained in the second shrinkage suppression layer 33, that is, the second inorganic material green sheet 35.
[0058]
As described above, the average particle diameter of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer 32 is made smaller than the average particle diameter of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer 33. In this case, the average particle diameter of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer 32 is 0.2 times the average particle diameter of the inorganic material powder for shrinkage suppression contained in the second shrinkage suppression layer 33. The above is preferable. The average particle size of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer 32 is less than 0.2 times the average particle size of the inorganic material powder for shrinkage suppression contained in the second shrinkage suppression layer. The average particle size of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer 32 becomes too small, leading to a reduction in degreasing properties in the degreasing process, and deteriorating the characteristics of the obtained multilayer ceramic substrate. Because there is.
[0059]
In the embodiment shown in FIG. 3, in order to give a difference in rigidity between the first shrinkage suppression layer 32 and the second shrinkage suppression layer 33, as described above, the average particle size of the inorganic material powder for shrinkage suppression In addition to different diameters, the following method may be employed.
[0060]
First, the amount of the organic binder contained in the first shrinkage suppression layer 32 is made smaller than the amount of the organic binder contained in the second shrinkage suppression layer 33.
[0061]
Secondly, the first shrinkage suppression layer 32 includes fiber-like inorganic oxide particles. In this case, the fiber-like inorganic oxide particles may be included only in the first shrinkage suppression layer 32, or the fiber-like inorganic oxide particles may be contained in both the first and second shrinkage suppression layers 32 and 33. Is included, the content of the fiber-like inorganic oxide particles contained in the first shrinkage suppression layer 32 is made larger than the content of the fiber-like inorganic oxide particles in the second shrinkage suppression layer 33. It may be.
[0062]
Thirdly, the first shrinkage suppression layer 32 includes glass powder that does not cause viscous flow under the firing conditions in the firing step. In this case, only the first shrinkage suppression layer 32 may contain glass powder that does not cause viscous flow, or both the first and second shrinkage suppression layers 32 and 33 have such glass powder. When it contains, you may make it make content of the glass powder in the 1st shrinkage | contraction suppression layer 32 more than content of the glass powder in the 2nd shrinkage | contraction suppression layer 33.
[0063]
In each of the embodiments described with reference to FIGS. 1 to 3, the second glass ceramic green sheet 5 has no through hole for the cavity. At least some of the sheets 5 may have through holes at positions that do not correspond to the positions of the through holes of the first glass ceramic green sheet.
[0064]
[Experimental example]
Below, the experiment example implemented in order to confirm the effect by this invention is demonstrated.
[0065]
Example 1
In Example 1, a composite laminate was produced with the structure shown in FIG. 1, and the composite laminate was fired to obtain a multilayer ceramic substrate. In addition, as a composite laminated body, what should become an assembly board | substrate which can take out a several multilayer ceramic substrate by dividing after baking was produced.
[0066]
First, a composite laminate having a planar dimension of 100 mm □ in which a plurality of cavities are distributed was produced. In this composite laminate, alumina powder having the same average particle diameter was used as the shrinkage-inhibiting inorganic material powder contained in the first and second shrinkage suppression layers. The thickness of the first shrinkage suppression layer was 2.0 times the thickness of the second shrinkage suppression layer. Further, the ratio of the area occupied by the opening of the cavity in the first end face was set to 0.3.
[0067]
Next, the composite laminate was placed in a plastic bag together with the mold, and the bag was vacuum packed. And the composite laminated body vacuum-packed with the metal mold | die is put in the water tank of a hydrostatic pressure press apparatus, and is 2000 kgf / cm at the temperature of 60 degreeC. ² Was pressed under the pressure of
[0068]
Next, after the pressed composite laminate is taken out from the bag and the mold, a degreasing process for 4 hours at a temperature of 450 ° C. and a temperature of 860 ° C. are performed while applying no load to the composite laminate. A main baking process for 20 minutes was performed.
[0069]
Next, the first and second shrinkage suppression layers were removed.
[0070]
In this way, an aggregate substrate to be a multilayer ceramic substrate having cavities could be produced in a state where the substrate did not substantially shrink in the xy direction and warpage and undulation of the entire substrate were suppressed. In addition, the flatness of the bottom surface of the cavity was not impaired, deformation and cracking of the peripheral part of the cavity were suppressed, and a cavity capable of mounting components without problems could be formed.
[0071]
More specifically, the flatness at the bottom of the cavity was about 20 μm / 10 mm when displayed in the vertical / horizontal direction. Further, the amount of warpage in the entire substrate was 200 μm or less at 100 mm □.
[0072]
(Example 2)
In Example 2, a composite laminate was produced with the structure shown in FIG. 3, and the composite laminate was fired to obtain a multilayer ceramic substrate. In addition, as a composite laminated body, the thing which should become an aggregate substrate was produced similarly to the case of Example 1.
[0073]
First, a composite laminate having a planar dimension of 100 mm □ in which a plurality of cavities are distributed was produced. In this composite laminate, the average particle diameter is used as the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer while making the thickness of the first shrinkage suppression layer and the thickness of the second shrinkage suppression layer the same. Was 1.2 μm alumina powder, and alumina powder having an average particle size of about 1.0 μm was used as the inorganic material powder for shrinkage suppression contained in the second shrinkage suppression layer. Further, the ratio of the area occupied by the opening of the cavity in the first end face was set to 0.3.
[0074]
Next, the press step and the firing step were performed in the same manner as in Example 1, and the first and second shrinkage suppression layers were removed after firing.
[0075]
In this way, the collective substrate to be a multilayer ceramic substrate having a cavity is not substantially shrunk in the xy direction as in the case of Example 1, and the warpage and undulation of the entire substrate are suppressed. We were able to make it. The flatness of the bottom surface of the cavity and the amount of warpage in the entire substrate were the same as those in Example 1.
[0076]
(Comparative example)
In this comparative example, except for the points described later, a composite laminate was produced with a structure as shown in FIG. 3, and this composite laminate was fired to obtain a multilayer ceramic substrate. As in the case of Examples 1 and 2, a composite laminate was prepared that would be a collective substrate from which a plurality of multilayer ceramic substrates could be taken out by dividing after firing.
[0077]
That is, except that the average particle size of the alumina powder contained in the first shrinkage suppression layer and the average particle size of the alumina powder contained in the second shrinkage suppression layer were the same as in Example 2. Thus, an aggregate substrate to be a sample was obtained by the same method as in Example 2.
[0078]
According to this comparative example, it was possible to produce a collective substrate to be a plurality of multilayer ceramic substrates having cavities without substantially shrinking in the xy direction. It was 1000 μm or more at 100 mm □.
[0079]
【The invention's effect】
As described above, according to the present invention, the first and second contractions along the first and second end faces in the stacking direction of the green sheet laminate to be a multilayer ceramic substrate in which a cavity is formed after firing. Each of the suppression layers is provided, and the rigidity of the first shrinkage suppression layer provided along the first end face where the opening of the cavity is positioned is higher than the rigidity of the second shrinkage suppression layer provided along the second end face. Therefore, when the composite laminate composed of the green sheet laminate and the first and second shrinkage suppression layers is baked, not only the shrinkage in the xy direction can be suppressed but also the cavity can be provided. Regardless, since the degree of restraint for suppressing the warpage to each of the first and second end faces of the green sheet laminate can be made substantially equal, the warpage and the undulation are substantially reduced. In the absence, it is possible to produce a multilayer ceramic substrate.
[0080]
Further, in the present invention, by giving a difference in rigidity between the first shrinkage suppression layer and the second shrinkage suppression layer, warpage and waviness in the entire fired multilayer ceramic substrate are substantially eliminated. Therefore, even if the area of the opening of the cavity changes, this can be dealt with by adjusting the rigidity of the shrinkage suppression layer.
[0081]
In this invention, the first shrinkage suppression layer is made thicker than the second shrinkage suppression layer, or the average particle diameter of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer is determined as the second shrinkage suppression layer. The average particle size of the shrinkage-suppressing inorganic material powder contained in the first shrinkage-suppressing layer is made smaller than the average particle size of the shrinkage-suppressing inorganic material powder, or less than the amount of the organic binder contained in the second shrinkage-suppressing layer. The first shrinkage suppression layer may contain fiber-like inorganic oxide particles, or the first shrinkage suppression layer may contain glass powder that does not cause viscous flow under the firing conditions in the firing step. For example, the difference in rigidity as described above can be easily provided between the first shrinkage suppression layer and the second shrinkage suppression layer.
[0082]
In the present invention, if the shrinkage suppression layer is composed of an inorganic material green sheet, for example, the thickness of the shrinkage suppression layer as described above can be easily adjusted by changing the number of laminated inorganic material green sheets.
[0083]
Further, in the step of firing the composite laminate, when a firing temperature of 1000 ° C. or lower is applied, each material of the ceramic material powder included in the glass ceramic green sheet and the inorganic material powder for shrinkage suppression contained in the shrinkage suppression layer The selection of the material for the wiring conductor provided in association with the multilayer ceramic substrate can be widened.
[0084]
In addition, according to the present invention, since the composite laminate can be fired without applying a load in the stacking direction of the composite laminate, no special equipment such as firing while applying pressure is required. It is possible to avoid an increase in cost and a decrease in manufacturing efficiency.
[0085]
Also, in this invention According to The first shrinkage suppression layer has a through portion that exposes the opening of the cavity. Because When pressing the composite laminate in the stacking direction, it can exert a pressing action on the bottom of the cavity . Therefore It becomes easy to apply a uniform pressure to the entire composite laminate. In this case, if the peripheral portion of the cavity is pressed and the bottom surface portion of the cavity is pressed through the penetration portion, the flatness of the bottom surface portion of the cavity is not impaired, and the peripheral portion of the cavity is not damaged. A multilayer ceramic substrate with excellent quality can be obtained more easily while suppressing deformation and cracking.
[0086]
In the present invention, after firing the composite laminate, the first and second shrinkage suppression layers are usually removed, but the first and second shrinkage suppression layers are removed in this way. For example, since materials such as the inorganic material powder for shrinkage suppression used in the shrinkage suppression layer do not affect the characteristics of the obtained multilayer ceramic substrate, inexpensive materials can be used without problems. Will be able to.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a composite laminate 1 obtained in the middle of manufacturing a multilayer ceramic substrate by performing a manufacturing method according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view schematically showing a composite laminate 21 obtained in the course of manufacturing a multilayer ceramic substrate by performing a manufacturing method according to another embodiment of the present invention.
FIG. 3 is a cross-sectional view schematically showing a composite laminate 31 obtained in the middle of manufacturing a multilayer ceramic substrate by performing a manufacturing method according to still another embodiment of the present invention.
[Explanation of symbols]
1,21,31 Composite laminate
2,22 cavity
3,24,26 Through hole
4, 25, 27 First glass ceramic green sheet
5 Second glass ceramic green sheet
6,23 Green sheet laminate
7 First end face
8 Second end face
9 Opening
10, 32 First shrinkage suppression layer
11, 33 Second shrinkage suppression layer
12 Penetration part
13, 34 First inorganic material green sheet
14, 35 Second inorganic material green sheet

Claims (10)

Preparing a ceramic material powder containing a glass component;
Preparing an inorganic material powder for shrinkage suppression having a higher sintering temperature than the ceramic material powder;
A first glass ceramic green sheet having a through hole for forming a cavity by containing the ceramic material powder and a second glass ceramic green sheet having no through hole at least at the position of the through hole, respectively. Manufacturing process;
A green having a cavity formed by the through hole so as to position an opening at the first end face in the stacking direction by stacking the first glass ceramic green sheet and the second glass ceramic green sheet. First and second containing a sheet laminate, and containing the shrinkage-suppressing inorganic material powder along the first end face of the green sheet laminate and the second end face facing the first end face. Providing a shrinkage suppression layer, thereby obtaining a composite laminate in which the first and second end faces of the green sheet laminate are respectively covered by the first and second shrinkage suppression layers;
Pressing the composite laminate in the laminating direction;
Next, a step of firing the composite laminate in a state where no load is applied in the stacking direction of the composite laminate,
In the composite laminate, the first shrinkage suppression layer has a through portion that exposes the opening of the cavity, and the first shrinkage suppression layer has higher rigidity than the second shrinkage suppression layer. Made to have,
A method for producing a multilayer ceramic substrate.   The method for producing a multilayer ceramic substrate according to claim 1, wherein the first shrinkage suppression layer is thicker than the second shrinkage suppression layer.   The average particle size of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer is made smaller than the average particle size of the inorganic material powder for shrinkage suppression contained in the second shrinkage suppression layer. Item 3. A method for producing a multilayer ceramic substrate according to Item 1 or 2.   The first and second shrinkage suppression layers include an organic binder, and the amount of the organic binder contained in the first shrinkage suppression layer is greater than the amount of the organic binder contained in the second shrinkage suppression layer. The method for producing a multilayer ceramic substrate according to claim 1, wherein the method is reduced.   5. The method of manufacturing a multilayer ceramic substrate according to claim 1, wherein the first shrinkage suppression layer includes fiber-like inorganic oxide particles.   The method for producing a multilayer ceramic substrate according to claim 1, wherein the first shrinkage suppression layer includes a glass powder that does not cause viscous flow under firing conditions in the firing step.   In the step of obtaining the composite laminate, the first and second shrinkage suppression layers are produced by forming a slurry in which the shrinkage suppression inorganic material powder is dispersed in an organic binder into a sheet shape. And a step of laminating the first and second inorganic material green sheets along the first and second end surfaces of the green sheet laminate, respectively. A method for producing a multilayer ceramic substrate according to any one of claims 1 to 6.   The method for producing a multilayer ceramic substrate according to claim 1, wherein a firing temperature of 1000 ° C. or lower is applied in the step of firing the composite laminate. 9. The multilayer ceramic according to claim 1, wherein in the step of pressing the composite laminate, a peripheral portion of the cavity is pressed and a bottom surface portion of the cavity is pressed through the penetration portion. A method for manufacturing a substrate. After the step of firing the composite laminate, the first further comprising first and second step of removing the shrinkage suppression layers, a method for manufacturing a multilayer ceramic substrate according to any one of claims 1 to 9.

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