JP2000340898A - Multilayered ceramic substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a multilayered ceramic substrate which can be positioned accurately, even when a laminate deviation occurs between upper and lower ceramic layers and in which no crack occurs, even when a load caused by stresses due to the difference between the coefficients of thermal expansion of the substrate and a jig, an external force, etc., is impressed upon the substrate via a positioning pin. SOLUTION: A multilayered ceramic substrate 1 is constituted by laminating a plurality of ceramic layers 1a, 1b, and 1c upon another and forming positioning notches 3 which penetrate the ceramic layers 1a, 1b, and 1c on the outer peripheral edge of the ceramic layers. Each notch 3 has a narrower width W1 and a deeper depth D1 in one of the ceramic layers 1a, 1b, and 1c. Therefore, even when a laminate deviation occurs among the ceramic layers 1a, 1b, and 1c, the substrate 1 can be positioned with high accuracy, because the upwardly and downwardly projected widths of the notches 3 are always fixed. In addition, crackings of the substrate 1 can be prevented effectively, because stresses which are generated in the interior sections of the notches 3 can be scattered satisfactorily to the ceramic layers 1a, 1b, and 1c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic multilayer substrate having a plurality of ceramic layers stacked and a positioning notch formed on an outer peripheral edge thereof.

[0002]

2. Description of the Related Art A ceramic multilayer substrate formed by laminating a plurality of ceramic layers is used as a wiring substrate for mounting electronic components such as semiconductor elements and quartz oscillators. FIG. 7 is a perspective view showing an example of such a conventional ceramic multilayer substrate.

[0003] The ceramic multilayer substrate in the example shown in FIG.
Reference numeral 11 denotes a multi-piece wiring board in which a large number of wiring board areas 12 on which electronic components are mounted are integrally formed vertically and horizontally.

This ceramic multilayer substrate 11 is formed by laminating three ceramic layers 11a, 11b and 11c. The outer peripheral edge has a notch 13 for positioning.

The notch 13 is used to position the ceramic multilayer substrate 11 at a predetermined position when performing various processes on the ceramic multilayer substrate 11 or when mounting electronic components. The ceramic layers 11a, 11b,
11c is provided so as to penetrate vertically with substantially the same width and depth.

For positioning of the ceramic multilayer substrate 11, a jig 21 having positioning pins 22 erected at positions corresponding to the respective notches 13 is prepared.
This is performed by placing the ceramic multilayer substrate 11 thereon such that the corresponding positioning pins 22 are inserted into the respective cutouts 13.

At this time, in the ceramic multilayer substrate 11, the movement of each notch 13 in the width direction is restricted by the positioning pin 22. Since the width direction of the notch 13 is formed so as to be orthogonal to each of the opposing sides, movement in all directions parallel to the main surface is restricted. It will be positioned at a predetermined position.

Incidentally, such a ceramic multilayer substrate 11
Is manufactured by punching and stacking three ceramic green sheets to be the respective ceramic layers 11a, 11b and 11c, and sintering them at a high temperature.

[0009]

However, in the ceramic multilayer substrate 11, when the ceramic green sheets are stacked, a stacking deviation of about 0.1 mm at the maximum occurs between the upper and lower ceramic green sheets.

When such a lamination shift occurs, a step of an unspecified size is formed on the side wall of the notch 13 as shown in an enlarged perspective view of a main part in FIG. There has been a problem that the vertical projection width of 13 has large variations. And the notch 13
If the vertical projection width of the
In addition, the positioning accuracy of the positioning pins 22 is low, and the ceramic multilayer substrate is used as a wiring board for mounting recently miniaturized and highly accurate electronic components.
If 11 is adopted, there is a problem that accurate positioning becomes difficult.

Therefore, as shown in an enlarged perspective view of a main part in FIG. 9, a cutout 13 formed in a specific ceramic layer, for example, a ceramic layer 11c which is the uppermost layer, is replaced with another ceramic layer.
The cutouts 13 formed in the ceramic layers 11a, 11b and 11c are smaller than the cutouts 13 formed in the ceramic layers 11a, 11b and 11c. Inner wall is always other ceramic layer 11a
The ceramic multilayer substrate 11 is formed so as to protrude from the inner wall of the notch 13 formed in 11b so that the projection width of the notch 13 in the vertical direction is always constant and accurate positioning can be performed. Proposed.

However, in this case, when the ceramic multilayer substrate 11 positioned on the jig 21 is subjected to a heating step, as shown in FIG.
The load A due to stress or external force generated due to the difference in the coefficient of thermal expansion between the
When the load A is applied in the width direction of the notch 13 through the ceramic layer 11c, the load A is locally concentrated near the depth of the notch 13 of the ceramic layer 11c protruding from the other ceramic layers 11a and 11b. There is a problem that a tensile stress B is generated, and the crack C is generated in the ceramic layer 11c starting from a deep portion of the cutout portion 13 due to the tensile stress B.

The present invention has been devised in view of the above problems, and has as its object to accurately position a ceramic multilayer substrate even if upper and lower ceramic layers are misaligned. Provided is a ceramic multilayer substrate having a cut-out portion in which cracks do not occur even when a load caused by a stress or an external force generated due to a difference in thermal expansion coefficient between a jig and a jig is applied through a positioning pin. It is in.

[0014]

SUMMARY OF THE INVENTION A ceramic multilayer substrate according to the present invention comprises a plurality of ceramic layers stacked on each other, and a notch for positioning penetrating the plurality of ceramic layers formed on an outer peripheral edge thereof. A multilayer substrate, wherein the notch has a narrow width and a deep depth in one of the plurality of ceramic layers.

According to the ceramic multilayer substrate of the present invention, the notch for positioning has a narrow width and a deep depth in one of the multilayer ceramic layers. Even if a layer is misaligned, the inner wall of the notch formed in this one ceramic layer always protrudes from the inner wall of the notch formed in the other ceramic layer in the width direction thereof, As a result, the projection width in the vertical direction of the notch is always constant. At the same time, the inner wall of the positioning notch formed in this one ceramic layer does not always protrude in the depth direction from the inner wall of the notch formed in the other ceramic layer. Therefore, even if a load such as a thermal stress or an external force generated due to a difference in thermal expansion coefficient between the ceramic multilayer substrate and the jig is applied through the positioning pin, the notch formed in the single ceramic layer is formed. There is no large concentration of tensile stress due to the load at the back of the part.

[0016]

Next, a ceramic multilayer substrate of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an example of an embodiment in which the ceramic multilayer substrate of the present invention is applied to a wiring board for mounting electronic components such as a semiconductor element and a quartz oscillator.

The ceramic multilayer board 1 is a multi-piece wiring board in which a large number of wiring board areas 2 on which electronic components are mounted are integrally formed vertically and horizontally.
a, 1b and 1c are laminated and integrated.

Each wiring board region 2 includes a mounting portion 2a for mounting an electronic component on the upper surface of the ceramic layer 1a, a metallized conductor layer 2b to which electrodes of the electronic component are connected on the upper surface of the ceramic layer 1b, and a ceramic layer 1c. The upper surface has a metallized metal layer 2c for sealing. An electronic component such as a semiconductor element is fixed to the mounting portion 2a via an adhesive or the like,
Electrodes of the electronic component are connected to the metallized conductor layer 2b via electrical connection means such as bonding wires, and a metal ring for sealing or a metal lid is joined to the metallized metal layer 2c via a brazing material. You.

The ceramic multilayer substrate 1 has a notch 3 for positioning at the outer peripheral edge.

The notch 3 is used to position the ceramic multilayer substrate 1 at a predetermined position when various processing is performed on the ceramic multilayer substrate 1 or when electronic components are mounted. The ceramic layers 1a, 1b, and 1c are provided at two locations on each side so as to penetrate vertically.

The ceramic multilayer substrate 1 is positioned by positioning the ceramic multilayer substrate 1 on a jig 21 having positioning pins 22 at positions corresponding to the notches 3, respectively. This is performed by placing the pin 22 so as to be inserted.

Incidentally, such a ceramic multilayer substrate 1
The ceramic layers 1a, 1b, 1c are made of ceramics such as aluminum oxide sintered body, aluminum nitride based sintered body, silicon carbide based sintered body, mullite sintered body, silicon nitride based sintered body and glass ceramic. The metallized conductor layer 2b and metallized metal layer 2c are formed of metal powder metallized metal such as tungsten or molybdenum / molybdenum-manganese / copper / silver / silver / palladium.

For example, the ceramic layers 1a, 1b and 1c are made of an aluminum oxide sintered body,
b. If the metallized metal layer 2c is made of tungsten metallized, an appropriate organic binder and a solvent are added to a ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. and mixed to form a slurry. This is formed into a sheet shape by employing a well-known doctor blade method to obtain ceramic green sheets, each of which becomes a ceramic layer 1a, 1b, 1c. Thereafter, these ceramic green sheets are subjected to punching and metallization. Tungsten paste to be used as the conductor layer 2b and the metallized metal layer 2c is printed in a predetermined pattern by screen printing.
It is manufactured by firing at a high temperature of 00 ° C.

In the ceramic multilayer substrate 1 of the present invention, the notch portion 3 has a width W in the uppermost ceramic layer 1c as shown in an enlarged perspective view of a main part in FIG.
1 is larger than the width W2 of the other ceramic layers 1a and 1b.
It is about 0.2 to 8 mm narrower, and its depth D1 is about 0.1 to 4 mm deeper than the depth D2 of the other ceramic layers 1a and 1b.
The width W1 of the notch 3 in the ceramic layer 1c
Is about 1 to 10 mm, and the depth D1 is about 2 to 20 mm.

As described above, the width W1 of the positioning notch 3 in the ceramic layer 1c is different from that of the other ceramic layer 1c.
Since the width W2 is smaller by about 0.2 to 8 mm than the width W2 of the ceramic layers 1a, 1b,
Even when a stacking deviation of about 0.1 mm occurs between the ceramic layers 1c, the inner wall of the cutout 3 formed in the ceramic layer 1c always has the other ceramic layers 1a.
The projection width of the notch 3 protrudes from the inner wall of the notch 3 formed in 1b, and the projection width in the vertical direction of the notch 3 is always constant. Therefore, the jig 21 is inserted into the ceramic multilayer substrate 1 such that the corresponding positioning pins 22 are inserted into the respective notches 3.
When placed on top, accurate positioning is possible.

At the same time, the depth D1 of the notch 3 in the ceramic layer 1c is different from the other ceramic layers 1a and 1b.
, The inner wall of the cutout 3 formed in the ceramic layer 1c is always formed in the other ceramic layers 1a and 1b in the depth direction. It does not protrude beyond the inner wall of the notch 3. Therefore, as shown in the enlarged perspective view of the main part in FIG. 3, a load A due to a thermal stress or an external force generated due to a difference in the coefficient of thermal expansion between the ceramic multilayer substrate 1 and the jig 21 passes through the positioning pin 22. Even if applied, the tensile stress B due to this load A is
a and 1b are applied in a distributed manner to the vicinity of the back of the notch 3 formed in the ceramic layer 1c and the vicinity of the back of the notch 3 formed in the ceramic layer 1c.
Cracks are effectively prevented.

In the positioning notch 3, the difference between the width W1 of the narrowed ceramic layer 1c and the width W2 of the other ceramic layers 1a and 1b is equal to 0.
If the thickness is less than 2 mm, the inner wall of the cutout 3 formed in the ceramic layer 1c is always formed in the other ceramic layers 1a and 1b in the width direction when the ceramic layers 1a, 1b and 1c are displaced from each other. There is a tendency that it is difficult to make the projection width of the notch 3 always be constant by projecting from the inner wall of the notch 3. On the other hand, if it exceeds 8 mm, the notch 3 formed in the ceramic layer 1c
Because the inner wall protrudes too much from the inner wall of the notch 3 formed in the other ceramic layers 1a and 1b, the mechanical strength of the ceramic layer 1c in the notch 3 tends to be low. Therefore, it is preferable that the difference between the width W1 of the narrowed ceramic layer 1c and the width W2 of the other ceramic layers 1a and 1b of the positioning notch 3 is in the range of 0.2 to 8 mm.

The positioning notch 3 has a depth D1 in the ceramic layer 1c having a greater depth and a depth D2 in the other ceramic layers 1a and 1b.
Is less than 0.1 mm, the ceramic layers 1a, 1b,
If there is a misalignment in the ceramic layer 1c, the inner wall of the notch 3 formed in the ceramic layer 1c is notch 3 formed in the other ceramic layers 1a and 1b in the depth direction.
There is a greater danger that the stress protrudes from the inner wall of the first portion and stress is greatly concentrated on this portion, and cracks are likely to occur. On the other hand, if it exceeds 4 mm, the stress is largely concentrated in the notch 3 formed in the other ceramic layers 1a and 1b, and there is a large risk of cracks occurring in the other ceramic layers 1a and 1b. Becomes Therefore, the notch 3 for positioning is formed by the depth D1 of the ceramic layer 1c whose depth is deep and the other ceramic layer 1c.
It is preferable that the difference from the depth D2 in a.1b is in the range of 0.1 to 4 mm.

Further, for example, as shown in an enlarged perspective view of a main part in FIG. 4, at least one main surface of each of the ceramic layers 1a, 1b, 1c, in this example, the upper surface of the ceramic layer 1b, If the metallized barrier layer 4 is provided in the vicinity of the deep portion of the notch 3, the metallized barrier layer 4 acts as a barrier to effectively prevent the generation and propagation of cracks in the ceramic layers 1a, 1b and 1c. it can. Therefore, each of the ceramic layers 1a, 1b, 1
It is preferable to provide the metallized barrier layer 4 on at least one main surface of c and near the back of the positioning notch 3. Such a metallized barrier layer 4 may be made of the same material as the metallized conductor layer 2a and the metallized metal layer 2b.

Thus, the ceramic multilayer substrate 1 of the present invention
According to this, even if the upper and lower ceramic layers 1a, 1b, and 1c are misaligned, the ceramic multilayer substrate 1 can be accurately positioned on the jig 21, and the heat between the ceramic multilayer substrate 1 and the jig 21 can be reduced. It is possible to provide the ceramic multilayer substrate 1 in which cracks do not occur even when a load such as thermal stress or external force generated due to a difference in expansion coefficient is applied through the positioning pin 22.

The ceramic multilayer substrate 1 of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the example of the above-described embodiment, the notch 3 has a small width and a large depth in the uppermost ceramic layer 1c. As shown in the main part enlarged perspective view, the width of the lowermost ceramic layer 1a may be narrow and the depth may be deep, and as shown in the main part enlarged perspective view in FIG. The ceramic layer 1b may have a narrow width and a large depth. Further, the cutouts 3 as shown in FIGS. 2, 5, and 6 may be provided in a single ceramic multilayer substrate 1.

In the case where the positioning notch 3 is narrow and deep in the uppermost ceramic layer 1c as shown in FIG.
This is applied, for example, to the metallized metal layer 2c of each wiring board region 2.
If it is used for positioning when brazing a metal ring or metal lid for sealing, the metallized metal layer 2c and the metal ring or metal lid for sealing can be accurately aligned.

The notch 3 for positioning is provided in FIG.
In the case where the lowermost ceramic layer 1a has a small width and a large depth as shown in FIG. 1, for example, when the electronic component is mounted on the mounting portion 2a of each wiring board region 2, If used for positioning, the mounting portion 2a and the electronic component can be accurately positioned.

In the case where the positioning notch 3 has a small width and a large depth in the intermediate ceramic layer 1b as shown in FIG. When the electronic component is used for positioning when mounting the electronic component on the mounting portion 2a and when electrically connecting the electronic component and the metallized conductor layer 2b, the metallized conductor layer 2b and the electronic component are accurately electrically connected. It is possible.

In the above-described embodiment, the ceramic multilayer substrate 1 has three ceramic layers 1a, 1b, 1c.
However, it goes without saying that the present invention can be applied to a case where the ceramic multilayer substrate 1 is composed of two ceramic layers or four or more ceramic layers. In such a case, the width of the positioning notch 3 in one arbitrary ceramic layer may be narrow and the depth may be large.

[0037]

As described above, according to the ceramic multilayer substrate of the present invention, the notch for positioning has a narrow width and a deep depth in one of the ceramic layers. Even when the upper and lower ceramic layers are misaligned, the inner wall of the notch formed in one of the ceramic layers always has a greater width than the inner wall of the notch formed in the other ceramic layer in the width direction. Also, the projection width of the notch portion in the up-down direction is always constant, so that the positioning pin of the jig is inserted into this notch portion to enable high-precision positioning. At the same time, the inner wall of the notch for positioning formed in one ceramic layer does not always protrude in the depth direction from the inner wall of the notch formed in the other ceramic layer. Even if a load due to thermal stress or external force generated due to a difference in the coefficient of thermal expansion between the substrate and the jig is applied through the positioning pin, the deep portion of the notch formed in one of the ceramic layers The stress due to the load does not concentrate significantly on the other ceramic layers, and is well dispersed in the other ceramic layers.
The generation of cracks in the ceramic multilayer substrate can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an embodiment in which a ceramic multilayer substrate of the present invention is applied to a wiring board for mounting electronic components.

FIG. 2 is an enlarged perspective view of a main part of the ceramic multilayer substrate shown in FIG.

FIG. 3 is an enlarged perspective view of a main part corresponding to FIG. 2 for explaining how stress is applied to the ceramic multilayer substrate shown in FIG. 1;

FIG. 4 is an enlarged perspective view of a main part showing another example of the embodiment of the ceramic multilayer substrate of the present invention.

FIG. 5 is an enlarged perspective view of a main part showing another example of the embodiment of the ceramic multilayer substrate of the present invention.

FIG. 6 is an enlarged perspective view of a main part showing another example of the embodiment of the ceramic multilayer substrate of the present invention.

FIG. 7 is a perspective view showing an example of a conventional ceramic multilayer substrate.

8 is an enlarged perspective view of a main part of the ceramic multilayer substrate shown in FIG. 7;

FIG. 9 is an enlarged perspective view of a main part showing an example of a conventional ceramic multilayer substrate.

10 is an enlarged perspective view of a main part corresponding to FIG. 9 for explaining cracks generated in the ceramic multilayer substrate shown in FIG. 9;

[Explanation of symbols]

 1 ... Ceramic multilayer substrate 1a-1c ... Ceramic layer 3 ... Notch for positioning

Claims (1)

[Claims] 1. A ceramic multilayer substrate comprising a plurality of ceramic layers laminated and a positioning notch formed through the plurality of ceramic layers at an outer peripheral edge thereof, wherein the notch comprises: A ceramic multilayer substrate, wherein one of the plurality of ceramic layers has a small width and a large depth.