JP4517566B2 - Method for manufacturing non-shrinkable ceramic multilayer substrate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a non-shrinkable ceramic multilayer substrate.
[0002]
[Prior art]
FIG. 3 and FIG. 4 show a sectional view of a laminate of a conventional non-shrinkable ceramic multilayer substrate before firing and a sectional view of a completed substrate from which a shrinkage constraining layer has been removed after firing.
[0003]
3 and 4 , 1-1, 1-2,..., 1-n-1, 1-n are formed by using unfired green sheets on which conductive patterns and vias for electrically connecting layers are formed. Each layer of the non-shrinkable ceramic multilayer substrate is shown. Reference numeral 2 denotes a shrinkage constraining layer that prevents shrinkage in the substrate plane direction when firing the entire substrate, and 3 denotes an end face of the ceramic substrate in the stacking direction. 4 in FIG. 4 shows a wall surface inside the substrate that becomes a through hole or cavity structure when completed.
[0004]
In FIG. 3 , although not shown in the drawing, green sheets 1-1, 1-2,..., 1-n-1 in which conductor patterns of each layer and vias that electrically connect the layers are formed in advance are formed. , 1-n are sequentially stacked. On the outermost side, a shrinkage constraining layer 2 for preventing shrinkage in the substrate plane direction during firing is laminated. In order to integrate the stacked layers, baking is performed after heating and pressurization, and then the shrinkage constraining layer 2 is removed, so that a substrate having no shrinkage variation in the substrate plane direction is obtained.
[0005]
In FIG. 4 , the unfired green sheets 1-1, 1-2,... All layer holes for through-holes and through-holes are formed in advance for each layer using a punching machine, etc., and then stacked one after another. The outermost layer shrinks in the direction of the substrate plane during firing. A shrinkage constraining layer 2 for preventing the above is laminated. In order to integrate the stacked layers, baking is performed after heating and pressurization, and then the shrinkage constraining layer 2 is removed, so that a substrate having no shrinkage variation in the substrate plane direction is obtained.
[0006]
Particularly a complicated structure such as a cavity as shown in FIG. 4 in order to accurately obtain, various devices are seen. For example, the shape of the shrinkage constraining layer is matched to the shape of the substrate hole and stacked, and the pressurization prevents deformation and cracking by using a hydrostatic press or a press that uses a die that matches the shape of the counterbore hole. However, an attempt is made to form a non-shrinkable ceramic multilayer substrate with good dimensional accuracy (see, for example, Patent Document 1).
[0007]
[Patent Document 1]
JP 2001-230548 A (page 4-5, FIG. 1)
[0008]
[Problems to be solved by the invention]
However, in the substrate thickness direction, the further away from the shrinkage constraining layer 2, the more the force that tends to shrink in the substrate plane direction when firing the substrate exceeds the force that impedes the shrinkage due to the shrinkage constraining layer 2. Shrinkage is noticeable. In addition, strictly speaking, the contraction increases the thickness of the substrate. This significantly hinders the feature that the non-shrinkable ceramic multilayer substrate does not shrink in the substrate plane direction and the flatness of the substrate.
[0009]
Further, for a structural hole having a wall surface in the substrate thickness direction inside the substrate as shown in FIG. 4 , similarly, the wall surface of the hole in the layer away from the shrinkage constraining layer 2 is shrunk, and the dimension of the hole However, the flatness of the substrate becomes worse at the same time as the original design value.
[0010]
That is, non-shrinkage that can be achieved by sandwiching unfired green sheets 1-1, 1-2,..., 1-n-1, 1-n to be fired with a shrinkage restraining layer 2 that inhibits shrinkage. The ceramic multilayer substrate has a drawback in that shrinkage occurs at the substrate end and the wall surface of the internal hole, and the ceramic multilayer substrate is deformed in the thickness direction of the substrate.
[0011]
In the examples shown in FIGS. 3 and 4 , the case where the shrinkage constraining layer is applied only in the substrate plane direction is shown. However, even if the shrinkage constraining layer is attached to the wall surface of the substrate end face, the through hole, or the counterbore hole, There is a problem of deformation due to the unbalance of the force to be shrunk and the difference in dimensions due to the shrinkage rate difference before and after firing, particularly the shrinkage difference in the thickness direction.
[0012]
[Means for Solving the Problems]
After laminating a fired substrate and unfired green sheet made of one or more green sheets as optional adjacent layers, and laminating an unfired green sheet for shrinkage restraint simultaneously on the outermost layer, after heating and pressing A method for producing a non-shrinkable ceramic multilayer substrate, characterized by firing the substrate.
[0013]
According to the present invention, by laminating a pre-fired substrate using the same material so as to be adjacent to the green sheet to be fired, the pre-fired substrate acts as a shrinkage constraining layer during firing, and the substrate during green sheet firing Shrinkage of the end face can be suppressed. By selecting the number of layers in which the unfired green sheets are continuously laminated, the range and amount of shrinkage deformation of the substrate end portion due to shrinkage restraint by the adjacent fired substrate can be suppressed.
[0014]
Also, before the lamination, the holes other than the electrical connection via holes between the layers are formed in some of the unfired green sheets, or the holes other than the electrical connection via holes between the layers are laminated before the lamination. A method for producing a non-shrinkable ceramic multi-layer substrate, wherein the non-shrinkable ceramic multilayer substrate is formed on a substrate in advance or the above two items are simultaneously performed.
[0015]
According to the present invention, even when holes other than via holes for electrical connection are formed in some layers or all layers inside the substrate, the holes other than via holes for electrical connection between layers are partially laminated before lamination. By forming the green substrate on an unfired green sheet and laminating a pre-fired substrate on the adjacent layer, it is possible to suppress the range and amount of shrinkage restraint due to shrinkage restraint. Also, the range and amount of shrinkage deformation of the hole shape can be suppressed by using a pre-fired substrate in which holes other than via holes for electrical connection between layers are formed in advance before lamination. Naturally, the range and amount of shrinkage deformation can be similarly suppressed by previously making holes other than vias for electrical connection in both the unfired green sheet and the fired substrate.
[0016]
Furthermore, the present invention provides a method for producing a non-shrinkable ceramic multilayer substrate, wherein the substrate made by the above-described method is used as a pre-fired substrate.
[0017]
That is, a non-shrinkable ceramic multilayer substrate having a cavity structure and a through hole is produced by the above-described method, and the substrate is sandwiched between green sheets of the same material as a fired substrate, and a shrinkage constraining layer is laminated on the outside, In this method, the substrate is baked after heating and pressing. By making this method, it is possible to create a closed space, a bent through hole, and an overhanging cavity structure with little dimensional variation.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 of the present invention is characterized in that the unfired green sheet laminate is at least one green previously fired with the unfired green sheet laminate so that the unfired green sheet laminate is the outermost layer in contact with the shrinkage suppression layer. A composite laminate is formed by alternately laminating a plurality of fired substrates made of sheets, and a shrinkage suppression layer containing an unsintered hard-sintering component is laminated on both sides of the composite laminate, and heating and pressing are performed. A method for producing a non-shrinkable ceramic multilayer substrate, wherein the substrate is fired so that the composite laminate is integrated later, and the pre-fired substrate serves as a shrinkage constraining layer during firing, and the substrate end face during green sheet firing The shrinkage can be suppressed. Further, by selecting the number of layers in which the green sheets are continuously laminated, it is possible to suppress the range and amount of shrinkage deformation of the substrate end portion due to shrinkage restraint by the adjacent fired substrate.
[0019]
The invention according to claim 2 of the present invention is characterized in that the composite laminate is formed after forming holes not filled with a conductive material in at least one of the unfired green sheets. It is a manufacturing method of the non-shrinkable ceramic multilayer board | substrate of description, It can suppress the range and quantity which the said hole shrinks and deform | transforms by previously forming holes other than the via hole for electrical connection between layers in an unfired green sheet. Therefore, a hole having an accurate shape can be easily created.
[0020]
The invention according to claim 3 of the present invention is characterized in that the composite laminate is formed after forming holes not filled with a conductive material in at least one of the fired substrates. This is a method for producing a non-shrinkable ceramic multilayer substrate, and by previously forming holes other than the electrical connection via holes between layers before lamination in the fired substrate, the range and amount of shrinkage deformation of the holes can be suppressed, Precisely shaped holes can be easily created.
[0021]
A fourth aspect of the present invention is the non-shrinkable ceramic multilayer substrate according to the first aspect, wherein the non-shrinkable ceramic multilayer substrate prepared in the first, second and third embodiments is used as a fired substrate. By using a substrate produced by the production method according to claims 1 to 3 as a fired substrate, a multilayer substrate having more layer shapes can be easily produced.
[0022]
(Embodiment 1)
1, 2, and 3 show a cross-sectional view of a laminate of the non-shrinkable ceramic multilayer substrate of the present invention and a cross-sectional view of the completed substrate from which the shrinkage constraining layer after firing has been removed.
[0023]
In FIG. 1, 1-1, 1-2,..., 1-n-1, 1-n are not shown in the figure, but conductor patterns of each layer and vias for electrically connecting the layers are formed in advance. Each layer of the non-shrinkage ceramic multilayer substrate laminated | stacked using the unbaked green sheet is shown. Reference numeral 2 denotes a shrinkage constraining layer that prevents shrinkage in the substrate plane direction when firing the entire substrate, and 3 denotes an end face of the ceramic substrate in the stacking direction. Reference numeral 5 denotes a pre-fired substrate on which a conductor pattern and vias for electrically connecting layers are formed in advance.
[0024]
1. The green green sheets 1-1, 1-2,..., 1-n-1, 1-n and the fired substrate 5 are sequentially laminated, and the shrinkage constraining layer 2 is laminated on the outermost side. Then, heat and pressure are applied so as to sandwich the substrate laminated from both sides of the shrinkage constraining layer 2. After firing, when the shrinkage constraining layer 2 is removed, unfired green sheets 1-1, 1-2,..., 1-n-1, which shrink in the thickness direction and do not shrink in the substrate plane direction. A substrate in which 1-n and the already-baked substrate 5 having the same size and shape as before baking are integrated is obtained. This substrate prevents shrinkage during firing of the unfired green sheets 1-1, 1-2,..., 1-n-1, 1-n by sandwiching between the shrinkage constraining layer 2 and the fired substrate 5. In addition, due to the restraining force of the baked substrate 5, it is possible to prevent the shrinkage of the substrate end face 3 in particular, and a substrate with high flatness without shrinkage deformation can be obtained.
[0025]
(Embodiment 2)
In FIG. 2, reference numeral 4 denotes a through-hole inside the substrate and a substrate wall surface of the cavity structure. In particular, this figure shows that green holes 1-1, 1-2,..., 1-n-1, 1-n are formed with through holes or cavity structure holes. The fired substrate 5 also has a through hole and a cavity structure hole formed in advance.
[0026]
2. The unfired green sheets 1-1, 1-2,..., 1-n-1, 1-n and the fired substrate 5 are sequentially laminated, and the shrinkage constraining layer 2 is laminated on the outermost side. Then, heat and pressure are applied so as to sandwich the substrate laminated from both sides of the shrinkage constraining layer 2. After firing, when the shrinkage constraining layer 2 is removed, 1-1, 1-2,..., 1-n-1, 1-n, which are shrunk in the thickness direction and not shrunk in the plane direction of the substrate, A substrate in which the already-baked substrate 5 having the same size and shape as before baking is integrated is obtained. By virtue of the effect of restraining the fired substrate 5 during firing, shrinkage of the through-holes and the wall surface 4 of the cavity structure can also be suppressed, and a clean hole shape can be obtained.
[0028]
【The invention's effect】
As described above, a fired substrate made of one or more green sheets and an unfired green sheet are laminated as arbitrary adjacent layers, and an unfired shrinkage-restraining green sheet is laminated simultaneously on the outermost layer. By firing the substrate after heating and pressing, shrinkage at the end face of the substrate can be suppressed, and a non-shrinkable ceramic multilayer substrate with good dimensional accuracy and small variation can be realized.
[0029]
In addition, some or all of the non-fired green sheets may have holes other than via holes for electrical connection between layers before lamination, or some or all holes other than via holes for electrical connections between layers may be formed before lamination. By forming in advance on the fired substrate, it is possible to suppress shrinkage in holes other than via holes for electrical connection and wall surfaces of through holes, and to realize a non-shrinkable ceramic multilayer substrate with good dimensional accuracy and small variation.
[0030]
Furthermore, by using the non-shrinkable ceramic multilayer substrate produced by the above-described method as a fired substrate, a non-shrinkable ceramic multilayer substrate having an inner space having a wall surface 4 with small dimensional variation by suppressing shrinkage in the plane direction of the substrate. Not only can it be realized, but it can be made of a combination of pre-fired substrates, and can easily form a bent through-hole or a space confined in the interior with a clean plane.
[Brief description of the drawings]
1 is a cross-sectional view of a laminate before firing of a non-shrinkable ceramic substrate according to Embodiment 1 of the present invention, and a cross-sectional view of the substrate after removal of a constraining layer after firing. FIG. 2 is non-shrinkable according to Embodiment 2 of the present invention. Cross-sectional view of the laminate before firing of the ceramic substrate and cross-sectional view of the substrate after removing the constrained layer after firing. FIG. 3 shows a cross-sectional view of the laminate before firing of the conventional non-shrinkable ceramic substrate without holes and the constrained layer after firing. Substrate cross-sectional view after removal [FIG. 4] Cross-sectional view of laminate before firing of non-shrinkable ceramic substrate having conventional holes and cross-sectional view of substrate after removal of constraining layer after firing [Explanation of symbols]
1-1 Unsintered green sheet 1-2 Unsintered green sheet 1-n-1 Unsintered green sheet 1-n Unsintered green sheet 2 Shrinkage constraining layer 3 Substrate edge 4 Wall surface of substrate inner hole 5 Existing Firing substrate

Claims (4)

The unfired green sheet laminate and a plurality of previously fired substrates made of at least one green sheet fired alternately so that the unfired green sheet laminate becomes the outermost layer in contact with the shrinkage suppression layer To form a composite laminate,
Non-shrinkable ceramic, wherein a shrinkage suppression layer containing an unfired hard-sintering component is laminated on both sides of the composite laminate, and the substrate is fired so as to integrate the composite laminate after heating and pressing. A method for producing a multilayer substrate. 2. The method for producing a non-shrinkable ceramic multilayer substrate according to claim 1, wherein the composite laminate is formed after forming holes not filled with a conductive material in at least one of the unfired green sheets. 2. The method for producing a non-shrinkable ceramic multilayer substrate according to claim 1, wherein the composite laminate is formed after forming a hole not filled with a conductive material in at least one of the fired substrates. The method for producing a non-shrinkable ceramic multilayer substrate according to claim 1, wherein the non-shrinkage ceramic multilayer substrate prepared in claims 1, 2 and 3 is used as a fired substrate.

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