JP2002151855A - Method of manufacturing multilayer ceramic board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a multilayer ceramic board having a formed cavity, and free of warpages or undulations. SOLUTION: The manufacturing method comprises laminated glass ceramic green sheets 4, 5 made of a glass-containing ceramic material powder to obtain a green sheet laminate 6 having a cavity 2 with an opening 9 positioned at a first end face 7, providing a first and second shrinkage suppressing layers 10, 11 containing a shrinkage suppressing inorganic material powder having a higher sintering temperature than the ceramic material along the first and second end faces 7, 8 of the laminate 6, thereby manufacturing a composite laminate 1, and baking it so as to obtain a multilayer ceramic board. The first shrinkage suppressing layer 10 is set thicker than the second one 11, so as to have rigidity higher than that of the second layer 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field 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 housing electronic components.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for smaller and lighter electronic devices, multifunctionality, higher reliability, and the like. As an effective method for improving the mounting technology on a substrate, most typically, there is a method of increasing the density of wiring on the substrate.

Therefore, in order to cope with such a high density of wiring on a substrate, a plurality of ceramic green sheets formed by printing a conductive film or the like on a ceramic green sheet are stacked, pressed, and fired. Development of a multilayer ceramic substrate is underway. However, in order to increase the density of wiring in a multilayer ceramic substrate without any problem, in the step of firing a green sheet laminate obtained by stacking a plurality of ceramic green sheets, the ceramic green sheets or the green sheets are fired. There is a demand for a precise control technique for the size, shape, and the like of the ceramic layer obtained.

[0004] As a method for making this possible, Patent No. 25
In Japanese Patent No. 54415, a shrinkage suppression layer containing an inorganic material powder having a higher sintering temperature than that of a glass ceramic green sheet is formed on both upper and lower surfaces of a green sheet laminate in which glass ceramic green sheets are stacked, pressed, and fired. Thereafter, a method of peeling and removing the unsintered inorganic material powder constituting the shrinkage suppression layer is disclosed.
No. 7643 discloses a method in which, in the method described above, pressing is further performed from above and below the green sheet laminate.

According to these methods, since shrinkage hardly occurs in the main surface direction of the green sheet, that is, in the xy direction, the dimensional accuracy of the obtained substrate can be increased, and the wiring density can be increased with high reliability. Can be achieved.

On the other hand, in a multilayer ceramic substrate, in addition to the above-described improvement in dimensional accuracy, higher density and higher reliability of wiring, reduction in size and height of the substrate itself are required. In order to realize these, it is effective to form a cavity for mounting electronic components on the multilayer ceramic substrate.

However, in the case of a multilayer ceramic substrate having such a cavity formed therein, in a firing step for obtaining the same, warpage or undulation may occur such that the end face on which the opening of the cavity is located is concave. Cheap.

To solve this problem, Japanese Patent Application Laid-Open No. 9-20
In the publication No. 2665, in the firing step, a load body is partially placed on a green sheet laminate to be a multilayer ceramic substrate having a cavity, or a load body smaller than the cavity is placed inside the cavity. do it,
A method for manufacturing a multilayer ceramic substrate in which warpage and undulation hardly occur is described.

[0009]

However, the above-mentioned Japanese Patent No. 2617643 and Japanese Patent Application Laid-Open No. 9-20266 have been disclosed.
In order to carry out the method described in Japanese Patent Laid-Open Publication No. 5 (1999) -2005, it is necessary to perform firing while applying a relatively large pressure to the green sheet laminate to be fired. And there is a problem in terms of equipment cost and manufacturing efficiency.

[0010] In recent years, the number of input / output terminals for mounting on a motherboard and electrically connecting the multilayer ceramic substrate to the high-density wiring has increased dramatically. In addition, with the increasing number of functions and higher performance, it is necessary to arrange a large number of circuit elements with high precision, and it is also necessary to incorporate high-density circuit elements such as capacitors and inductors. Have been.

In particular, under the above-described circumstances, a relatively large difference is likely to occur in the degree of shrinkage between the one end face side and the other end face side of the green sheet laminate. If no pressure is applied in the firing step, there is a high possibility that a larger warpage will occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in a method of manufacturing a multilayer ceramic substrate having a cavity, it is possible to suppress shrinkage in the xy directions and to pressurize during firing. It is intended to prevent warping and swelling.

[0013]

According to the present invention, there is provided 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 higher sintering temperature than the ceramic material powder, A first glass-ceramic green sheet having a through-hole for forming a cavity by containing a ceramic material powder and a second glass-ceramic green sheet having no through-hole at least at the position of the above-mentioned through-hole, respectively. A step of making;
By laminating the first glass ceramic green sheet and the second glass ceramic green sheet,
Obtaining a green sheet laminate having a cavity formed by a through hole such that an opening is located at the first end face in the laminating direction, and facing the first end face and the first end face of the green sheet laminate. A first and a second containing an inorganic material powder for suppressing shrinkage along the second end face.
Are provided respectively, so that the first and second end faces of the green sheet laminate are the first and second end faces.
Steps of obtaining composite laminates each covered by the shrinkage suppression layer, and pressing the composite laminate in the lamination direction,
Then, a method of manufacturing a multilayer ceramic substrate, comprising a step of firing the composite laminate, is characterized by having the following configuration in order to solve the above-described technical problem.

That is, the present invention is characterized in that in the above-described composite laminate, the first shrinkage suppressing layer has higher rigidity than the second shrinkage suppressing layer.

As described above, there are various embodiments within the scope of the present invention for making the rigidity of the first shrinkage suppressing layer higher than the rigidity of the second shrinkage suppressing layer.

In the first embodiment, the first shrinkage suppression layer is thicker than the second shrinkage suppression layer.

In the second embodiment, the average particle size of the inorganic material powder for shrinkage suppression contained in the first shrinkage-suppressing layer is determined by the average particle size of the inorganic material powder for shrinkage suppression contained in the second shrinkage-suppressing layer. Be smaller.

In the third embodiment, when the first and second shrinkage suppression layers contain an organic binder, the amount of the organic binder contained in the first shrinkage suppression layer is contained in the second shrinkage suppression layer. Less than the amount of organic binder.

In a fourth embodiment, the first shrinkage suppressing layer is made to contain fiber-like inorganic oxide particles.

In the fifth embodiment, the first shrinkage suppressing layer contains glass powder that does not cause viscous flow under the firing conditions in the firing step described above.

The above-described first to fifth embodiments may be implemented in a state where some of them are combined.

In the present invention, the first and second shrinkage suppressing layers provided in the above-described composite laminate are prepared in the state of a green sheet, and are laminated on the green sheet laminate to form the composite laminate. Is preferably produced. That is, in the step of obtaining the composite laminate, the first and second shrinkage suppression layers are formed by molding a slurry in which the shrinkage suppression inorganic material powder is dispersed in an organic binder into a sheet shape. It is preferable that the method includes a step of laminating the first and second inorganic material green sheets prepared as second inorganic material green sheets, respectively, along the first and second end surfaces of the green sheet laminate. .

In the step of firing the composite laminate, a firing temperature of 1000 ° C. or less is preferably applied.

In order to make the advantages of the present invention work more effectively, in the step of firing the composite laminate,
It is preferable that no load is applied in the stacking direction of the composite laminate.

Further, in the present invention, it is preferable that the first shrinkage suppressing layer has a penetrating portion for exposing the opening of the cavity.

In the above case, in the step of pressing the composite laminate, preferably, the peripheral portion of the cavity is pressed, and the bottom portion of the cavity is pressed through the through portion.

After the step of firing the composite laminate, the first and second shrinkage suppressing layers are usually removed.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic cross-sectional view showing a composite laminate 1 obtained in the course of manufacturing a multilayer ceramic substrate by implementing a manufacturing method according to an embodiment of the present invention. ing.

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 for suppressing shrinkage having a higher sintering temperature than the low-temperature sintered ceramic material powder. A powder is provided.

A first glass ceramic green sheet 4 having a through hole 3 for forming a cavity 2 containing the above-mentioned low temperature sintered ceramic material powder and a second glass ceramic green sheet having no through hole are provided. The sheet 5 and each are manufactured.

Then, the first glass ceramic green sheet 4 and the second glass ceramic green sheet 5 are laminated to obtain a green sheet laminate 6. More specifically, in order to obtain a 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 first end face 7 has an opening 9 of the cavity 2 formed by the through hole 3.
Is located.

Although not shown, the green sheet laminate 6 includes glass ceramic green sheets 4 and 5.
Of the glass ceramic green sheets 4 and 5, via-hole conductors are formed so as to penetrate specific ones of the glass ceramic green sheets 4 and 5, and external conductor films are formed on the end faces 7 and 8. Is formed. Some of these inner conductor films, via hole conductors, and outer conductor films may provide circuit elements such as capacitors, inductors or resistors. Also, passive components like capacitors or inductors
It is prepared in the form of a block, and such a block component may be incorporated in the green sheet laminate 6.

Along each of the first and second end faces 7 and 8 in the laminating direction of the green sheet laminate 6, the first and second shrinkage suppressing layers 10 containing the above-described shrinkage suppressing inorganic material powder are provided. And 11 are provided respectively. Of these shrinkage suppression layers 10 and 11, in the first shrinkage suppression layer 10 along the first end face 7 where the opening 9 of the cavity 2 is located, the penetrating portion 12 exposing the opening 9 of the cavity 2 It is preferable to be provided in the state which has.
More preferably, the through portion 12 has substantially the same shape as the opening 9 of the cavity 2 as shown in FIG.

The first and second shrinkage suppressing layers 10 described above
And 11 prepare the first and second inorganic material green sheets 13 and 14 by, for example, preparing a slurry in which an inorganic material powder for shrinkage suppression is dispersed in an organic binder and forming the slurry into a sheet. The first and second inorganic material green sheets 13 and 14 are formed together with the first and second glass-ceramic green sheets 4 and 5 to form the first and second inorganic material green sheets 13 and 14. Along the end surfaces 7 and 8, respectively.

As will be described later, each of the first and second shrinkage suppression layers 10 and 11 is constructed to obtain a required thickness. The number of each of the first and second inorganic material green sheets 13 and 14 is adjusted.

Instead of the above-described method, the first and second shrinkage suppressing layers 10 and 11 use the slurry containing the inorganic material powder for shrinkage suppression to form the first and second end faces 7 and 2 of the green sheet laminate 6. 8 may be formed by applying printing or the like to each of them.

Thus, the green sheet laminate 6
The composite laminate 1 in which the first and second end faces 7 and 8 are covered with the first and second shrinkage suppression layers 10 and 11, respectively, is obtained.

Next, the composite laminate 1 is pressed in the laminating direction. In this pressing step, preferably, the peripheral part of the cavity 2 is pressed, and the bottom part of the cavity 2 is pressed via the penetrating part 12. More specifically, the composite laminate 1 is placed in a mold (not shown), and the composite laminate 1 is pressed by applying a hydrostatic pressing method or a rigid pressing method. .

In this case, it is preferable to press the composite laminate 1 in the laminating direction so that the same pressure is applied to the bottom portion of the cavity 2 and the peripheral portion of the cavity 2. For this reason, it is preferable to use a mold having a structure that can apply pressure independently to the bottom surface of the cavity 2 and the periphery of the cavity 2 as a mold for housing the composite laminate 1.

In the above-described hydrostatic pressing method, the same pressure can be easily applied to the bottom portion of the cavity 2 and the peripheral portion of the cavity 2 at once in the pressing step, and therefore, compared to the rigid pressing method. Is more preferable.

In the case of the rigid press method, a pressing device configured to apply the same pressure to the bottom surface of the cavity 2 and the peripheral portion of the cavity 2 may be used. The pressing process may be performed in two stages, i.e., a stage in which pressure is applied to the substrate and a stage in which pressure is applied to the periphery of the cavity 2.

When the penetrating portion 12 of the first shrinkage suppressing layer 10 has substantially the same shape as the opening 9 of the cavity 2 as in this embodiment, the bottom portion of the cavity 2 is formed in the above-described pressing step. It is easier to apply a uniform pressure over the entire area.

Next, the composite laminate 1 is fired. More specifically, in an ordinary oxidizing atmosphere, first, a degreasing step of decomposing and eliminating organic components contained in the composite laminate 1 is performed, and then a main baking step is performed. In addition, it is preferable that a temperature of about 200 to 600 ° C. is applied in the degreasing step, and a temperature of about 800 to 1000 ° C. is applied in the main baking step. In this firing step, the composite laminate 1 is fired without applying a load in the stacking direction.

In the above-described firing step, the shrinkage suppressing layer 1
Since the inorganic material powder for shrinkage suppression contained in 0 and 11 is not substantially sintered, the shrinkage suppression layers 10 and 11 do not substantially shrink. Therefore, in the green sheet laminate 6, in the firing step, shrinkage occurs only in the thickness direction, and shrinkage in the xy direction is caused by the shrinkage suppression layer 1.
Because it is constrained by 0 and 11, it can be made to occur substantially.

The end surfaces 7 and 8 of the green sheet laminate 6 are covered with shrinkage suppressing layers 10 and 11, respectively, 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 of the cavity 2 is ensured, and deformation and cracking of the peripheral portion of the cavity 2 can be suppressed.

The cavity 2 in the composite laminate 1
Since the shrinkage suppression layer is not formed on the bottom surface of the above, a force that shrinks in the x-y direction acts on this portion, thereby making the end face of the composite laminate 1 on the opening 9 side of the cavity 2 concave. Thus, the entire composite laminate 1 is to be warped. However, if the rigidity of the first shrinkage suppressing layer 10 is made higher than the rigidity of the second shrinkage suppressing layer 11, warpage of the entire composite laminate 1 can be suppressed.

In this embodiment, as described above, since a difference in rigidity is provided between the first shrinkage suppression layer 10 and the second shrinkage suppression layer 11, the first shrinkage suppression layer 10 Is made thicker than the shrinkage suppression layer 11. As described above, the first and second shrinkage suppression layers 10 and 11 are formed of the first and second inorganic material green sheets 13 and 14, respectively.
Therefore, in order to provide such a difference in thickness, the number of stacked first inorganic material green sheets 13 constituting the first shrinkage suppression layer 10 and the number of the first inorganic material green sheets 13 constituting the second shrinkage suppression layer 11 are increased. The number of stacked inorganic material green sheets 14 is different from each other, and the first inorganic material green sheet 1
The number of laminations of No. 3 is made larger than the number of laminations of the second inorganic material green sheets.

When the first shrinkage suppression layer 10 is made 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 that 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, so that the degreasing property in the degreasing step becomes poor. It is not preferable because the number of the first inorganic material green sheets 13 to be reduced is increased or the number of laminating steps is increased.

Further, the thickness of the first shrinkage suppressing layer 10
That is, the thickness of the second shrinkage suppressing layer 11 is three times or less, in other words, the thickness of the second shrinkage suppressing layer 11 is equal to or more than ３ times the thickness of the first shrinkage suppressing layer 10. . The thickness of the second shrinkage suppression layer 11 is
When the thickness is less than 1/3 of the thickness of the second shrinkage suppressing layer 1
In some cases, the thickness of No. 1 is too thin, so that the above-described effect of suppressing shrinkage cannot be sufficiently exerted.

As in this embodiment, when the penetration 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 1
0 completely covers the periphery of the cavity 2, and the binding force for suppressing shrinkage by the first shrinkage suppression layer 10 in the firing step can be exerted over the entire periphery of the cavity 2. The effect of suppressing deformation and cracking in the peripheral portion can be made more perfect.

As described above, by firing the composite laminate 1, a target multilayer ceramic substrate can be obtained in an appropriate state. After the multilayer ceramic substrate is thus obtained, the first and second shrinkage suppression layers 10 and 11 are usually removed.

FIG. 2 is a cross-sectional view schematically showing a composite laminate 21 obtained in the course of manufacturing a multilayer ceramic substrate by implementing a manufacturing method according to another embodiment of the present invention. In FIG. 2, elements corresponding to the elements shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

The composite laminate 21 shown in FIG. 2 is for obtaining a multi-layer ceramic substrate having a plurality of cavities 22, for example, two tiers. As a glass ceramic green sheet, a glass ceramic green sheet 25 having a relatively large through hole 24 and a glass ceramic green sheet 2 having a relatively small through hole 26
7 are used.

Also in this embodiment, the first and second shrinkage suppressing layers 10 are formed along the first and second end faces 7 and 8 in the laminating direction of the green sheet laminate 23.
And 11 are provided respectively. Then, the first shrinkage suppression layer 10 is made thicker than the second shrinkage suppression layer 11.

FIG. 3 is a cross-sectional view schematically showing a composite laminate 31 obtained in the course of manufacturing a multilayer ceramic substrate by performing a manufacturing method according to still another embodiment of the present invention. 3, elements corresponding to the elements shown in FIG. 1 are denoted by the same reference numerals, and overlapping description will be omitted.

The first of the composite laminate 31 shown in FIG.
The second shrinkage suppression layers 32 and 33 have the same thickness as each other. That is, the first and second shrinkage suppression layers 32 and 33 are composed of first and second inorganic material green sheets 34 and 35, respectively. Assuming that 34 and 35 have the same thickness, the first and second inorganic material green sheets 34 and 35 are laminated with the same number of laminations.

In this embodiment, the first shrinkage suppression layer 32
Is higher than the rigidity of the second shrinkage suppression layer 33, the average particle size of the shrinkage suppression inorganic material powder included 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 shrinkage suppression contained in the second shrinkage suppression layer 33, that is, the second inorganic material green sheet 35.

As described above, the average particle size of the shrinkage-suppressing inorganic material powder contained in the first shrinkage-suppressing layer 32 is determined by the average particle size of the shrinkage-suppressing inorganic material powder contained in the first shrinkage-suppressing layer 33. In the case of making smaller, the average particle diameter of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer 32 is:
The average particle size of the inorganic material powder for shrinkage suppression contained in the second shrinkage suppression layer 33 is preferably 0.2 times or more. When 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. , First
The average particle size of the shrinkage-suppressing inorganic material powder contained in the shrinkage-suppressing layer 32 is too small, leading to a reduction in the degreasing property in the degreasing step, and may degrade the characteristics of the obtained multilayer ceramic substrate. It is.

In the embodiment shown in FIG. 3, in order to provide a difference in rigidity between the first shrinkage suppression layer 32 and the second shrinkage suppression layer 33, as described above, the shrinkage suppression inorganic material powder is used. In addition to making the average particle size different, the following method may be employed.

First, the amount of the organic binder contained in the first shrinkage suppressing layer 32 is made smaller than the amount of the organic binder contained in the second shrinkage suppressing layer 33.

Second, the first shrinkage suppressing layer 32 contains fiber-like inorganic oxide particles. In this case, the fibrous inorganic oxide particles may be contained only in the first shrinkage suppression layer 32, or the fibrous inorganic oxide particles may be contained in both the first and second shrinkage suppression layers 32 and 33. Is included, the content of the fibrous inorganic oxide particles contained in the first shrinkage suppression layer 32 is set to be larger than the content of the fibrous inorganic oxide particles in the second shrinkage suppression layer 33. It may be.

Third, the first shrinkage suppression layer 32 contains 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 the first and second shrinkage suppression layers 32 may be used.
When such a glass powder is contained in both of the first and second shrinkage suppressing layers 32, the content of the glass powder in the first shrinkage suppressing layer 32 is set to be larger than the content of the glass powder in the second shrinkage suppressing layer 33. You may.

In each of the embodiments described with reference to FIGS. 1 to 3, the second glass ceramic green sheet 5 does not have a through hole for a cavity. At least some of the glass ceramic green 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 EXAMPLES Hereinafter, experimental examples implemented to confirm the effects of the present invention will be described.

Example 1 In Example 1, a composite laminate was manufactured with the structure shown in FIG. 1, and the composite laminate was fired to obtain a multilayer ceramic substrate. In addition, as the composite laminate, a substrate to be an aggregate substrate from which a plurality of multilayer ceramic substrates can be taken out by dividing after firing was produced.

First, a composite laminate having a plane dimension of 100 mm □ in which a plurality of cavities are distributed was prepared. In this composite laminate, alumina powder having the same average particle diameter as each other was used as the inorganic material powder for shrinkage suppression contained in the first and second shrinkage suppression layers. Further, the thickness of the first shrinkage suppression layer was set to 2.0 times the thickness of the second shrinkage suppression layer. The ratio of the area occupied by the opening of the cavity on the first end face was set to 0.3.

Next, this composite laminate was added to both molds.
Put in a bag made of tics, and use this bag to form a vacuum pack
State. And the compound vacuum-packed with the mold
The laminate was placed in a water tank of an isostatic press,
2000kgf / cm at temperature ^TwoPress with pressure
Was.

Next, after the pressed composite laminate is taken out of the bag and the mold, a degreasing step at 450 ° C. for 4 hours and a temperature of 860 ° C. are performed while applying no load to the composite laminate. The main firing step was performed at a temperature of 20 minutes.

Next, the first and second shrinkage suppressing layers were removed.

In this way, it is possible to manufacture a collective substrate that is to be a multilayer ceramic substrate having a cavity in a state in which it does not substantially shrink in the xy directions and suppresses warpage and undulation of the entire substrate. did it. Further, the flatness of the bottom surface of the cavity was not impaired, the deformation and cracking of the peripheral portion of the cavity were suppressed, and a cavity capable of performing component mounting without problems could be formed.

More specifically, the flatness at the bottom of the cavity is about 2 when expressed in the vertical / horizontal directions.
It was 0 μm / 10 mm. Further, the amount of warpage in the entire substrate was 200 μm or less at 100 mm □.

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. Note that, as in the case of Example 1, a composite laminate to be an aggregate substrate was prepared.

First, a composite laminate having a plane dimension of 100 mm □ in which a plurality of cavities are distributed was prepared. In this composite laminate, while making the thickness of the first shrinkage suppression layer and the thickness of the second shrinkage suppression layer the same,
Alumina powder having an average particle size of 1.2 μm is used as the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer, and the average particle size is used as the inorganic material powder for shrinkage suppression contained in the second shrinkage suppression layer. About 1.0 μm alumina powder was used. The ratio of the area occupied by the opening of the cavity on the first end face was set to 0.3.

Next, a pressing step and a firing step were performed in the same manner as in Example 1, and after firing, the first and second shrinkage suppression layers were removed.

In this way, the aggregate substrate to be a multilayer ceramic substrate having a cavity is not substantially shrunk in the xy directions as in the case of the first embodiment, and the warpage and undulation of the entire substrate are suppressed. It was able to be manufactured in the state where it was done.
The flatness of the bottom surface of the cavity and the amount of warpage in the entire substrate were almost the same as in Example 1.

(Comparative Example) In this comparative example, a composite laminate was produced with the structure shown in FIG. 3 except for the points described later, and the composite laminate was fired to obtain a multilayer ceramic substrate. In addition, as in the case of Examples 1 and 2, a composite laminate was to be formed, which was to be an aggregate substrate from which a plurality of multilayer ceramic substrates could be taken out by dividing after firing.

That is, as compared with Example 2, the average particle diameter of the alumina powder contained in the first shrinkage suppressing layer and the average particle diameter of the alumina powder contained in the second shrinkage suppressing layer were made the same. Except for this, an aggregate substrate as a sample was obtained in the same manner as in Example 2.

According to this comparative example, the aggregate substrate to be a plurality of multilayer ceramic substrates having cavities is x-
Although it could be manufactured in a state where it did not substantially shrink in the y direction, the amount of warpage in the entire substrate was 1000 μm or more at 100 mm □.

[0079]

As described above, according to the present invention, the first and second end faces in the laminating direction of the green sheet laminate to be a multilayer ceramic substrate having a cavity formed after firing are formed. And a second shrinkage suppression layer provided along the first end face where the opening of the cavity is located, and the second shrinkage suppression layer provided along the second end face. Since it is higher than the rigidity of the layer, when firing the composite laminate composed of the green sheet laminate and the first and second shrinkage suppression layers, not only can the shrinkage in the xy direction be suppressed, Despite having the cavity, the degree of restraint for suppressing the warp for each of the first and second end faces of the green sheet laminate can be made substantially equal, so Substantially not the state of kneading, it is possible to produce a multilayer ceramic substrate.

Further, according to the present invention, by providing a difference in rigidity between the first shrinkage suppressing layer and the second shrinkage suppressing layer, warpage and undulation in the entire multilayer ceramic substrate after firing are substantially eliminated. Thus, even if the area of the opening of the cavity changes, it is possible to cope with this by adjusting the rigidity of the shrinkage suppression layer.

In the present invention, the first shrinkage suppressing layer comprises:
The average particle diameter of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer may be made larger than the second shrinkage suppression layer, Smaller than the diameter, the amount of the organic binder contained in the first shrinkage suppression layer is made smaller than the amount of the organic binder contained in the second shrinkage suppression layer, or the first shrinkage suppression layer has a fibrous shape. If the inorganic oxide particles are contained or the first shrinkage suppressing layer is made to contain glass powder that does not cause viscous flow under the firing conditions in the firing step, the difference in rigidity as described above is reduced to the first level. Can be easily provided between the second shrinkage suppressing layer and the second shrinkage suppressing layer.

In the present invention, if the shrinkage suppression layer is made 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. Can be.

In the step of firing the composite laminate, when a firing temperature of 1000 ° C. or lower is applied, the ceramic material powder contained in the glass ceramic green sheet and the inorganic material powder for shrinkage suppression contained in the shrinkage suppression layer are reduced. Each material can be easily selected, and the range of materials for wiring conductors provided in connection with the multilayer ceramic substrate can be widened.

Further, according to the present invention, the composite laminate can be fired without applying a load in the laminating direction of the composite laminate, so that special equipment such as firing while applying pressure is not required. Therefore, it is possible to avoid an increase in equipment cost and a decrease in manufacturing efficiency.

Further, in the present invention, when the first shrinkage suppression layer has a penetrating portion for exposing the opening of the cavity, when the composite laminate is pressed in the laminating direction, the press is extended to the bottom portion of the cavity. The ability to exert an action facilitates applying a uniform pressure to the entire composite laminate. In this case, if the peripheral part of the cavity is pressed and the bottom part of the cavity is pressed through the penetrating part, the flatness of the bottom part of the cavity is not impaired, and the peripheral part of the cavity is not damaged. A high-quality multilayer ceramic substrate can be more easily obtained with deformation and cracks suppressed.

In the present invention, after firing the composite laminate, the first and second shrinkage suppressing layers are usually removed, and thus the first and second shrinkage suppressing layers are removed. By doing so, the material such as the inorganic material powder for shrinkage suppression used in the shrinkage suppression layer does not affect the properties and the like of the obtained multilayer ceramic substrate. It can be used without any problems.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a composite laminate 1 obtained in the course 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 course 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 (12)

[Claims] 1. A step of preparing a ceramic material powder containing a glass component; a step of preparing a shrinkage-suppressing inorganic material powder having a sintering temperature higher than that of the ceramic material powder; Producing a first glass-ceramic green sheet having a through-hole for forming a cavity and a second glass-ceramic green sheet having no through-hole at least at the position of the through-hole; Glass ceramic green sheet and the second
A green sheet laminate having a cavity formed by the through hole such that an opening is located at the first end face in the laminating direction by laminating the glass sheet and the green sheet laminate. A first and a second shrinkage-suppressing layer containing the shrinkage-suppressing inorganic material powder are respectively provided along the first end face and a second end face opposing the first end face, whereby the green Obtaining a composite laminate in which the first and second end faces of the sheet laminate are respectively covered by the first and second shrinkage suppressing layers; pressing the composite laminate in a laminating direction; Baking the composite laminate. In the composite laminate, the first shrinkage suppression layer has a higher rigidity than the second shrinkage suppression layer. It is the method for manufacturing a multilayer ceramic substrate to have a. 2. The method according to claim 1, wherein the first shrinkage suppression layer is thicker than the second shrinkage suppression layer. 3. The average particle size of the inorganic material powder for shrinkage suppression contained in the first shrinkage suppression layer is smaller than the average particle size of the inorganic material powder for shrinkage suppression contained in the second shrinkage suppression layer. The method for manufacturing a multilayer ceramic substrate according to claim 1, wherein the size is reduced. 4. The first and second shrinkage suppression layers include an organic binder, and the amount of the organic binder included in the first shrinkage suppression layer is equal to the amount of the organic binder included in the second shrinkage suppression layer. 4. The method for producing a multilayer ceramic substrate according to claim 1, wherein the amount is smaller than the amount of the organic binder. 5. The method for manufacturing a multilayer ceramic substrate according to claim 1, wherein said first shrinkage suppression layer includes fiber-like inorganic oxide particles. 6. The method for manufacturing a multilayer ceramic substrate according to claim 1, wherein the first shrinkage suppressing layer includes a glass powder that does not cause viscous flow under firing conditions in the firing step. 7. In the step of obtaining the composite laminate, the first and second shrinkage suppression layers are formed by forming a slurry in which the shrinkage suppression inorganic material powder is dispersed in an organic binder into a sheet. First and second fabricated
And a step of laminating the first and second inorganic material green sheets along the first and second end faces of the green sheet laminate, respectively. 1 to 6
The method for producing a multilayer ceramic substrate according to any one of the above. 8. The method according to claim 1, wherein a firing temperature of 1000 ° C. or less is applied in the step of firing the composite laminate.
8. The method for manufacturing a multilayer ceramic substrate according to any one of items 7 to 7. 9. The method for manufacturing a multilayer ceramic substrate according to claim 1, wherein the step of firing the composite laminate is performed without applying a load in the stacking direction of the composite laminate. . 10. The method for manufacturing a multilayer ceramic substrate according to claim 1, wherein the first shrinkage suppression layer has a through portion exposing an opening of the cavity. 11. In the step of pressing the composite laminate, a peripheral portion of the cavity is pressed,
The method according to claim 10, wherein a bottom portion of the cavity is pressed through the through portion. 12. After the step of firing the composite laminate,
The method for manufacturing a multilayer ceramic substrate according to claim 1, further comprising a step of removing said first and second shrinkage suppression layers.