JP7223638B2 - Multi-cavity ceramic substrate, manufacturing method thereof, and manufacturing method of ceramic substrate - Google Patents

Description

The present invention relates to a multi-cavity ceramic substrate and a manufacturing method thereof. The present invention also relates to a method of manufacturing a ceramic substrate obtained by dividing a multi-cavity ceramic substrate.

A multi-cavity ceramic substrate including a plurality of substrate element portions has a substrate area (also called a product area) that becomes individual ceramic substrates, and an outer peripheral area positioned outside the substrate area. In the substrate region of the multi-cavity ceramic substrate, division grooves are formed that extend longitudinally and laterally along the boundaries of the respective substrate element portions in order to divide the substrate element portions into individual pieces.

For example, Patent Literature 1 discloses a laminated substrate obtained by laminating a plurality of ceramic green sheets on which conductive patterns are printed to form a plate-like molded body, and integrally sintering the conductive patterns and the ceramic green sheets. The main surface of the laminated substrate is provided with a plurality of first division grooves parallel to each other and a plurality of second division grooves perpendicular to the first division grooves. By dividing this laminated substrate along the first and second dividing grooves, a plurality of individual laminated bodies can be obtained. An internal circuit element is formed in each individual piece laminate by a conductor pattern.

In such a laminated substrate, a deformation-suppressing conductor layer made of a conductor pattern is formed around the individual-piece laminated body forming region in order to suppress deformation of the laminated substrate that may occur during sintering.

JP 2004-71852 A JP 2018-170442 A

By the way, in ceramic substrates, tungsten (W) and molybdenum (Mo) are sometimes used as metal materials for forming conductive patterns such as wiring (see, for example, Patent Document 2).

Tungsten and molybdenum have different chemical properties, such as melting points. Therefore, even if a deformation-suppressing conductor layer as disclosed in Patent Document 1 is formed, it may not be possible to sufficiently prevent deformation such as warpage of the substrate that may occur after sintering.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a multi-cavity ceramic substrate that can suppress the occurrence of warping when molybdenum and tungsten are used as metal materials for forming conductive patterns.

A multi-cavity ceramic substrate according to one aspect of the present invention has a substrate region in which a plurality of substrate elements are arranged side by side, and an outer peripheral region positioned outside the substrate region. This multi-cavity ceramic substrate comprises: a plurality of ceramic layers; a first metal layer containing molybdenum formed on at least one of the ceramic layers; It comprises a metal layer containing tungsten formed on at least one of the ceramic layers, and a metal layer for electrolytic plating conduction formed on at least one of the ceramic layers. Then, on at least one of the ceramic layers on which the first metal layer is formed, a second ceramic layer containing molybdenum and not electrically connected to the first metal layer is formed in the outer peripheral region. A metal layer is formed.

In the multi-cavity ceramic substrate according to one aspect of the present invention, the second metal layer is formed in the outer peripheral region on all the ceramic layers on which the first metal layer is formed. good too.

According to the above configuration, it is possible to further reduce warping of the multi-cavity ceramic substrate after sintering.

Further, in the multi-cavity ceramic substrate according to one aspect of the present invention, the substrate element portions are arranged vertically and horizontally in the substrate region, and the substrate element portions are individually arranged in the substrate region. A slit portion extending vertically and horizontally is formed for partitioning, and the second metal layer may not be formed on an imaginary extension line of the slit portion in the outer peripheral region.

According to the above configuration, the substrate can be easily cut in the dividing step performed when obtaining the individual ceramic substrates from the multi-piece ceramic substrate.

In the multi-cavity ceramic substrate according to one aspect of the present invention, the second metal layer is provided at a position corresponding to at least a central position in the width direction of the adjacent substrate element portions, and It may have a diameter of 1/2 or more of the width of the substrate element portion.

According to the above configuration, it is possible to reduce the amount of molybdenum used by reducing the total area of the second metal layer, while avoiding a decrease in the effect of improving the warpage of the substrate during sintering.

Another aspect of the present invention relates to a method of manufacturing a multi-cavity ceramic substrate having a substrate region in which a plurality of substrate elements are arranged side by side and an outer peripheral region located outside the substrate region. This manufacturing method includes a ceramic layer forming step of forming each of a plurality of ceramic layers, and forming a first metal layer containing molybdenum on at least one of the ceramic layers formed by the ceramic layer forming step. and a tungsten-containing metal layer forming step of forming a tungsten-containing metal layer on at least one of the ceramic layers formed in the ceramic layer forming step. In this manufacturing method, the molybdenum-containing metal layer forming step and the tungsten-containing metal layer forming step are performed alternatively to each other. Then, in the molybdenum-containing metal layer forming step, a second metal layer that is not electrically connected to the first metal layer is formed in the outer peripheral region.

According to the manufacturing method described above, in the step of forming the molybdenum-containing metal layer, the second metal layer for reducing warpage can be formed together with the first metal layer for the conductive pattern. As a result, it is possible to manufacture a multi-cavity ceramic substrate having a structure for improving the warpage of the substrate without performing an additional step.

Further, in the above manufacturing method, the substrate element portions are arranged vertically and horizontally in the substrate region, and the substrate region has slit portions extending vertically and horizontally for individually partitioning the substrate element portions. may be formed. In the molybdenum-containing metal layer forming step, the first metal layer is not formed in the region corresponding to the slit portion, and the second metal layer is not formed on the imaginary extension line of the slit portion in the outer peripheral region. It is also possible not to form As a result, it is possible to manufacture a multi-piece ceramic substrate in which the second metal layer is not formed on the imaginary extension line of the slit portion.

Moreover, still another aspect of the present invention relates to a method for manufacturing a ceramic substrate. This manufacturing method includes a step of, after manufacturing a multi-cavity ceramic substrate by the above-described manufacturing method according to one aspect of the present invention, dividing the multi-cavity ceramic substrate into the individual substrate element portions.

As described above, according to the multi-cavity ceramic substrate according to one aspect of the present invention, since the second metal layer containing molybdenum is formed in the outer peripheral region, warpage of the substrate that can occur after sintering is reduced. be able to. As a result, it is possible to reduce the rate of occurrence of defective products in ceramic substrates obtained from multi-cavity ceramic substrates. In particular, it is possible to suitably suppress the occurrence of warpage that may occur in the ceramic substrate obtained from the substrate element portion located on the outermost periphery of the substrate region, and improve the shape of the substrate.

Moreover, according to the method of manufacturing a multi-cavity ceramic substrate according to another aspect of the present invention, it is possible to reduce the warping of the substrate that may occur after sintering. As a result, it is possible to obtain a multi-cavity ceramic substrate having an improved substrate shape.

1 is a schematic plan view showing the configuration of a multi-cavity ceramic substrate according to a first embodiment of the present invention; FIG. 2 is a cross-sectional view showing the internal configuration of a part of the multi-piece ceramic substrate shown in FIG. 1; FIG. FIG. 4 is a schematic plan view showing a configuration of a modification of the multi-piece ceramic substrate according to the first embodiment; FIG. 5 is a cross-sectional view showing the internal configuration of a portion of a conventional multi-piece ceramic substrate. FIG. 3 is a cross-sectional view showing a partial internal configuration of a multi-piece ceramic substrate according to a comparative example; (a) to (c) are diagrams schematically showing the warped shape of a substrate. FIG. 8A is a view showing a conventional example, FIG. 8B is a comparative example, and FIG. FIG. 5 is a schematic plan view showing the configuration of a multi-piece ceramic substrate according to a second embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[First embodiment]
In this embodiment, a multi-piece ceramic substrate 1 will be described as an example. A ceramic substrate 50 obtained from the multi-cavity ceramic substrate 1 is used as a wiring substrate, a circuit substrate, etc. for electronic equipment.

(Structure of multi-cavity ceramic substrate)
FIG. 1 shows a multi-piece ceramic substrate 1 . In FIG. 1, the upper left shows the overall plan configuration of the multi-cavity ceramic substrate 1, and the lower right shows an enlarged view of a portion of the multi-cavity ceramic substrate 1 (specifically, the portion surrounded by the dashed line).

The multi-cavity ceramic substrate 1 has a substantially flat plate-like outer shape. A multi-cavity ceramic substrate 1 has a product area (substrate area) 2 including a plurality of substrate element portions 11 and a peripheral area (peripheral area) 3 positioned outside the product area 2 .

The product area 2 constitutes the central part of the substrate. In the product area 2, a plurality of substrate element portions 11, which are divided into individual ceramic substrates 50, are arranged vertically and horizontally. Internal circuit elements are formed on each substrate element portion 11 by conductive patterns made of various metal layers.

The peripheral area 3 constitutes the peripheral portion of the substrate. The peripheral area 3 is provided so as to surround the product area 2. - 特許庁Since the outer peripheral area 3 does not form an element of the ceramic substrate 50, no internal circuit elements are formed in the outer peripheral area 3. FIG. As will be described later, the second Mo layer 24 and the electroplating conduction wiring 25 are formed in the outer peripheral area 3 .

The substrate element portion 11 has a rectangular shape such as a rectangle or a square, and the diameter of one side thereof is approximately 5 mm. In the product area 2 , slits 12 extending vertically and horizontally are formed between adjacent board element parts 11 to individually partition the board element parts 11 . The slit portion 12 is also formed between the outer peripheral area 3 and the outermost substrate element portion 11 . After the multi-cavity ceramic substrate 1 is manufactured, the multi-cavity ceramic substrate 1 is cut at each slit portion 12 to be divided into individual substrate element portions 11 . Thereby, the ceramic substrate 50 is obtained.

It is preferable that the surface of the multi-cavity ceramic substrate 1 is formed with grooves or cuts at positions corresponding to the slit portions 12 . This facilitates the step of dividing the multi-piece ceramic substrate 1 into individual pieces.

FIG. 2 shows a cross-sectional configuration of a portion including the boundary between the product area 2 and the peripheral area 3 of the multi-cavity ceramic substrate 1 (specifically, the AA line portion shown in the enlarged view of FIG. 1).

The multi-cavity ceramic substrate 1 is formed by laminating a plurality of ceramic sheets 21 . The ceramic sheet 21 can be formed of, for example, high-temperature sintered ceramic containing alumina (Al ₂ O ₃ ) as a main component. Alternatively, the ceramic sheet 21 may be formed of a medium temperature fired ceramic (MTCC) such as a glass-ceramic.

FIG. 2 illustrates the multi-cavity ceramic substrate 1 having a total of nine ceramic sheets 21, but the number of ceramic sheets is not limited to this. The number of ceramic sheets 21 is appropriately determined according to the application, specifications, etc. of the finally obtained ceramic substrate 50 . In this embodiment, when the ceramic sheets of each layer are referred to individually, they are called the first ceramic sheet 21a, the second ceramic sheet 21b, . . .

Molybdenum layers (also referred to as Mo layers) 23 and tungsten layers (also referred to as W layers) 22 serving as conductive patterns are formed between the plurality of ceramic sheets 21 . The Mo layer 23 and the W layer 22 are printed on the ceramic sheet 21 so as to have an arbitrary shape (pattern) according to the circuit configuration desired for the finally obtained ceramic substrate 50 .

The Mo layer 23 and the W layer 22 are alternatively formed between the layers of the ceramic sheets 21 . That is, the Mo layer 23 is formed on at least one of the plurality of ceramic sheets 21 (the fourth and fifth ceramic sheets 21d and 21e in the example shown in FIG. 2), and the W layer 22 is The Mo layer 23 is formed on at least one sheet (first to third ceramic sheets 21a, 21b, and 21c in the example shown in FIG. 2) of the ceramic sheets 21 on which the Mo layer 23 is not formed.

Here, the Mo layer formed on the fourth ceramic sheet 21d is 23d, and the Mo layer formed on the fifth ceramic sheet 21e is 23e. The W layer formed on the first ceramic sheet 21a is denoted by 22a, the W layer formed on the second ceramic sheet 21b is denoted by 22b, and the W layer formed on the third ceramic sheet 21c is denoted by 22c. .

The arrangement and combination of the Mo layer and W layer shown in FIG. 2 are examples of the present invention, and the present invention is not limited to this configuration. Therefore, for example, a configuration in which a Mo layer is formed on the first ceramic sheet 21a, a W layer is formed on the second ceramic sheet 21b, and Mo layers are formed on the third to fifth ceramic sheets 21c to 21e. etc. is also possible.

In the multi-cavity ceramic substrate 1 according to this embodiment, an additional Mo layer (that is, the second Mo layer 24 for improving the warpage of the substrate) is provided in the peripheral area 3 on the ceramic sheet 21 on which the Mo layer 23 is formed. formed. This second Mo layer 24 is not electrically connected to the Mo layer 23 formed within the product area 2 . The thickness of the second Mo layer 24 is substantially the same as the thickness of the Mo layer 23, and can be, for example, 5-20 μm.

In the example shown in FIG. 2, second Mo layers 24d and 24e are formed on the fourth and fifth ceramic sheets 21d and 21e. That is, the second Mo layer 24d is formed in the same layer as the Mo layer 23d, and the second Mo layer 24e is formed in the same layer as the Mo layer 23e. Such second Mo layers 24d and 24e are formed in a predetermined pattern in the same process as the process of forming the Mo layers 23d and 24e (eg, printing process).

It should be noted that such a warp-improving second metal layer is not formed on the layer where the W layer 22 is formed. This is because, as will be described later, if the second metal layer made of tungsten is formed in the outer peripheral area 3, the warpage of the substrate after sintering will worsen.

The warp-improving second Mo layer 24 may be formed on at least one of the ceramic sheets 21 on which the conductive pattern Mo layer 23 is formed. As a result, warpage of the multi-cavity ceramic substrate 1 after sintering can be reduced compared to the case where the second Mo layer 24 is not formed.

Note that the second Mo layer 24 for improving warpage is all of the ceramic sheets 21 on which the Mo layers 23 for conductive patterns are formed (in the example shown in FIG. 2, both the fourth and fifth ceramic sheets 21d and 21e). is preferably formed on a sheet of As a result, warping of the multi-cavity ceramic substrate 1 after sintering can be greatly reduced.

Further, at least one sheet among the plurality of ceramic sheets 21, which is not formed with the Mo layer 23 and the W layer 22 (in the example shown in FIG. 2, the sixth to eighth ceramic sheets 21f, 21g, and 21h), electrolytic plating conduction wirings 25 (25f, 25g and 25h in the example shown in FIG. 2) are formed.

The wiring 25 for electrolytic plating conduction is printed on the predetermined ceramic sheet 21 so as to have a predetermined shape (pattern).

As shown in FIG. 2, the electrolytic plating conduction wiring 25 extends not only to the product area 2 but also to the outer peripheral area 3 . For example, the electrolytic plating conduction wiring 25 is formed in a frame shape so as to surround the product area 2 in the peripheral area 3 . The electrolytic plating conduction wiring 25 extending to the outer peripheral area 3 has a terminal portion (not shown) electrically connected to a plating power source.

Further, the electrolytic plating conduction wiring 25 extending to the product area 2 is connected to an internal metal layer forming a metal plating layer 27 (for example, a metal plating layer 27i) inside the multi-cavity ceramic substrate 1 . As a result, electric power supplied from the plating power source during electrolytic plating can be supplied to this metal layer through the electrolytic plating conduction wiring 25 .

The electrolytic plating conduction wiring 25 can be made of metal such as tungsten (W), molybdenum (Mo), copper (Cu), and silver (Ag). For example, in the example shown in FIG. 2, the electrolytic plating conduction wiring 25f formed on the sixth ceramic sheet 21f is made of Mo. Also, the electrolytic plating conduction wirings 25g and 25h formed on the seventh and eighth ceramic sheets 21g and 21h are made of W. As shown in FIG.

In the present embodiment, the electrolytic plating conduction wiring 25 is formed of a ceramic sheet in a layer relatively close to the uppermost ninth ceramic sheet 21i on which the metal plating layer 27 is formed (specifically, the sixth to eighth ceramic sheets). formed on sheets 21f, 21g and 21h). As a result, the electrical connection between the electrolytic plating conduction wiring 25 and the metal plating layer 27 can be realized more easily.

The metal plating layer 27 is formed on the surface (exposed portion) of the multi-cavity ceramic substrate 1 . In this embodiment, a metal plated layer 27i is formed on the uppermost ninth ceramic sheet 21i. A metal plating layer 27 is formed on the product area 2 . The metal plated layer 27 is connected to other components via a bonding material such as brazing material or solder. That is, the metal plated layer 27 serves as a joint with other parts. During the electroplating process, portions of the electroplating conduction wiring 25g that are not covered with the eighth ceramic sheet 21h are also plated. As a result, a metal plating layer 27g is partially formed on the electrolytic plating conduction wiring 25g (see FIG. 2).

The metal plating layer 27 is a metal layer formed of tungsten (W), molybdenum (Mo), copper (Cu), silver (Ag), or the like, and is plated with nickel (Ni), gold (Au), or the like. formed by application. In this embodiment, the metal plated layer 27 is formed by coating the surface of a metal layer made of W or Mo by electrolytic Ni plating, and then coating the Ni plating coating with Au plating by electrolytic Au plating. be.

(Regarding the planar shape of the second Mo layer)
Next, the planar shape of the second Mo layer 24 will be described with reference to FIG. Schematically, the second Mo layer 24 has a shape that surrounds the outer peripheries of the substrate element portions 11 arranged vertically and horizontally. By forming the second Mo layer 24 into such a shape, it is possible to suppress the occurrence of warpage after sintering in the entire region of the multi-cavity ceramic substrate 1 . As described above, the second Mo layer 24 is not electrically connected with the Mo layer 23 . In addition, the second Mo layer 24 is a metal layer that exists independently without being electrically connected to other metal layers such as the W layer 22 and the electroplating conduction wiring 25 .

More specifically, as shown in the enlarged view of FIG. 1, the second Mo layer 24 is partially formed with the second slit portion 13 where the second Mo layer 24 is not formed. The second slit portion 13 is formed at a position corresponding to the slit portion 12 . That is, the second Mo layer 24 is not formed on the imaginary extension line to the outer peripheral area 3 of the slit portion 12 formed in the product area 2 . This eliminates the need to cut the second Mo layer 24 made of metal when dividing the multi-cavity ceramic substrate 1 into the individual ceramic substrates 50, thereby facilitating the division of the substrates.

In the example shown in FIG. 2, two second Mo layers 24d and 24e are formed on the fourth and fifth ceramic sheets 21d and 21e. In such a configuration, it is preferable that both of the two second Mo layers 24d and 24e have planar shapes as shown in FIG. This makes it possible to further reduce the warping of the substrate after sintering. However, in another embodiment of the present invention, the shapes of the two second Mo layers 24d and 24e do not have to be aligned.

FIG. 3 shows a modification of the planar shape of the second Mo layer 24a in the multi-cavity ceramic substrate 1. As shown in FIG. In the example shown in FIG. 1, the second Mo layer 24 has a substantially frame shape surrounding the entire outer periphery of the product area 2 . That is, the width of the second slit portion 13 formed in the second Mo layer 24 is approximately the same as the width of the slit portion 12, and is very small.

On the other hand, in the modification shown in FIG. 3, a plurality of substantially rectangular second Mo layers 24a are formed adjacent to the sides of the outermost substrate element portion 11, respectively. According to the configuration according to the modification, it is possible to reduce the amount of molybdenum used as the material of the second Mo layer 24a.

In addition, as shown in FIG. 3, the second Mo layer 24a is preferably provided at a position corresponding to at least the central position in the width direction of the adjacent substrate element portions 11 . Specifically, the second Mo layer 24a adjacent to the side edge extending in the horizontal direction (L1 direction) of the substrate element portion 11 is provided so as to straddle the horizontal center line C1 of the substrate element portion 11. is preferred. Moreover, the second Mo layer 24a adjacent to the side edge extending in the vertical direction (L2 direction) of the substrate element portion 11 is preferably provided so as to straddle the vertical center line C2 of the substrate element portion 11. As shown in FIG.

Further, it is preferable that the second Mo layer 24a has a diameter of 1/2 or more of the width of the substrate element portion 11 . Specifically, if the lateral width of the substrate element portion 11 is L1, and the longitudinal width thereof is L2, then the longitudinal diameter W1 of the second Mo layer 24a adjacent to the side extending in the lateral direction is W1≧ It is preferable that L1×(1/2). Moreover, it is preferable that the longitudinal diameter W2 of the second Mo layer 24a adjacent to the side extending in the longitudinal direction satisfies W2≧L2×(1/2).

According to the above configuration, it is possible to reduce the total area of the second Mo layer 24a and reduce the amount of molybdenum used, while avoiding a decrease in the effect of improving the warpage of the substrate during sintering.

(Manufacturing method of multi-cavity ceramic substrate)
Next, a method for manufacturing the multi-piece ceramic substrate 1 will be described.

The manufacturing method of the multi-cavity ceramic substrate 1 includes at least the following steps.
(1) A sheet forming step (ceramic layer forming step) for forming each of a plurality of ceramic sheets 21 (21a to 21i in the example shown in FIG. 2).
(2) Mo layer forming step (23d, 23e in the example shown in FIG. 2) of forming Mo layer 23 (23d, 23e in the example shown in FIG. 2) on at least one of the ceramic sheets 21 formed in the sheet forming step of (1) above ( molybdenum-containing metal layer forming step)
(3) A W layer forming step of forming a W layer 22 (22a to 22c in the example shown in FIG. 2) on at least one of the ceramic sheets 21 formed in the sheet forming step of (1) above ( Tungsten-containing metal layer forming step)

In the sheet forming step (1), for example, a raw material powder containing a powder of a ceramic component as a main component is kneaded with an appropriate organic solvent and a binder to prepare a slurry, and the slurry is molded by a doctor blade method, a lip coater method, or the like. It is carried out by forming it into a sheet by a method. The formed sheet is cut into a predetermined shape and size. Thereby, the sheet material forming each ceramic sheet 21 is formed.

In the Mo layer forming step (2) and the W layer forming step (3), a predetermined conductive pattern is formed on the ceramic sheet 21 obtained in the sheet forming step (1). Formation of the conductive pattern is performed using a known printing method such as a screen printing method. As a result, a conductive pattern forming a circuit element or the like is printed on a desired portion of the surface of the ceramic sheet 21 .

In the manufacturing method according to this embodiment, the Mo layer forming step (2) and the W layer forming step (3) are performed alternatively. That is, only one of the Mo layer 23 and the W layer 22 is printed on one ceramic sheet 21 .

In the Mo layer forming step (2), a second Mo layer which is not electrically connected to the Mo layers 23 (23d and 23e in the example shown in FIG. 2) is placed in the peripheral area 3 of the multi-cavity ceramic substrate 1. Layers 24 (24d, 24e in the example shown in FIG. 2) are formed. Here, the Mo layer 23 functions as a conductive pattern in each substrate element portion 11 . Also, the second Mo layer 24 is formed in order to suppress warpage that may occur during sintering of the substrate. That is, in the Mo layer forming step (2), Mo 23 for a conductive pattern is printed on the product area 2 on one ceramic sheet 21, and the second Mo for improving warpage is printed on the outer peripheral area 3 of the same ceramic sheet 21. Layer 24 is printed.

In the Mo layer forming step (2) and the W layer forming step (3), regions corresponding to the slit portions 12 extending vertically and horizontally for individually partitioning each substrate element portion 11 in the product area 2 are It is preferable not to form the Mo layer 23 or the W layer 22 . Furthermore, in the Mo layer forming step (2), it is preferable not to form the second Mo layer 24 on the imaginary extension line of the slit portion 12 in the outer peripheral area 3 . As a result, second slit portions 13 in which the Mo layer is not partially formed are formed in the formation region of the second Mo layer in the peripheral area 3 .

By forming the slit portion 12 and the second slit portion 13 as described above, the substrate can be easily cut in the subsequent step of dividing the substrate into individual ceramic substrates 50 .

In addition to the above steps (2) and (3), a metal layer (for example, a Mo layer or a W layer) that will become the electroplating conduction wiring 25 is formed in a predetermined shape (pattern) on another ceramic sheet 21. A printing step may be performed. Similarly, a step of printing a metal layer (for example, a Mo layer or a W layer), which will become the metal plating layer 27 after electroplating, on the ceramic sheet 21 in a predetermined shape (pattern) may be performed. As a result, the ceramic sheet 21 on which the metal layer to be the electrolytic plating conduction wiring 25 or the metal layer to be the metal plating layer 27 is formed is obtained.

Each ceramic sheet 21 printed with a metal layer of a predetermined shape in each of the above steps is then laminated in a predetermined order and pressed. In one example, using the seventh ceramic sheet 21g as a base, the sixth to first ceramic sheets 21f to 21a are sequentially laminated and pressed together to form the first laminate. Also, the ninth ceramic sheet 21i is laminated and pressure-bonded on the basis of the eighth ceramic sheet 21h to form a second laminate. After that, the seventh ceramic sheet 21g of the first laminate and the eighth ceramic sheet 21h of the second laminate are pressure-bonded.

Thereby, a flat laminate having a thickness of about 0.5 to 1.0 mm is obtained. A via hole (not shown) is formed in each ceramic sheet 21, and metal layers (that is, W layer 22, Mo layer 23, electrolytic plating conduction wiring 25, and metal plating layer) formed between the ceramic sheets 21 27) are appropriately connected and configured to function as circuit elements later.

After that, dividing grooves may be formed at positions corresponding to the slit portions 12 on the surface of the flat laminate. Then, this flat laminate is fired.

The plate-like laminate sintered by the firing step is then subjected to electrolytic plating. Thereby, the metal plating layer 27 (the metal plating layer 27i in the example shown in FIG. 2) is formed on the uppermost ceramic sheet 21 (the ninth ceramic sheet 21i in the example shown in FIG. 2). Electroplating can be performed using a conventionally known method. The metal plating layer 27 having a Ni plating coating and an Au plating coating can be formed by performing the electroplating process multiple times.

Through the steps described above, the multi-piece ceramic substrate 1 is manufactured.

Furthermore, when manufacturing the ceramic substrate 50 from the multi-cavity ceramic substrate 1, a step of dividing the multi-cavity ceramic substrate 1 into individual substrate element portions 11 is performed. At this time, if dividing grooves are formed on the surface of the multi-cavity ceramic substrate 1, the substrate can be cut easily and accurately. Thereby, the ceramic substrate 50 is obtained.

(Warpage improvement effect by the second metal layer)
Next, the warpage improvement effect obtained in the multi-cavity ceramic substrate 1 according to this embodiment will be described. For comparison, warping after sintering that occurs in a conventional multi-cavity ceramic substrate 801 and a multi-cavity ceramic substrate 901 according to a comparative example will also be described.

FIG. 4 shows a cross-sectional structure of a multi-piece ceramic substrate 801 according to a conventional example. FIG. 5 shows a cross-sectional configuration of a multi-piece ceramic substrate 901 according to a comparative example. These figures show the configuration when each of the substrates 801 and 901 is cut along the line AA shown in the enlarged view of FIG.

In the multi-cavity ceramic substrate 801 shown in FIG. 4, the second Mo layer 24 for improving warpage is not formed in the peripheral area 3 . Other than that, it has the same configuration as the multi-cavity ceramic substrate 1 .

In the multi-cavity ceramic substrate 901 shown in FIG. 5, in addition to the second Mo layers 24d and 24e, W layers 22b and 22c are formed in the outer peripheral area 3 on the second and third ceramic sheets 21b and 21c. 2W layers 29b and 29c are formed. Other than that, it has the same configuration as the multi-cavity ceramic substrate 1 .

When these three types of multi-cavity ceramic substrates were fired under the same conditions, differences in the warped shape of the substrates were observed as shown in FIGS. 6(a) to 6(c). That is, in the comparative example shown in (b), it was confirmed that the warp of the substrate after sintering was worse than the result of the conventional example shown in (a). On the other hand, in the multi-cavity ceramic substrate 1 according to the present embodiment, as shown in (c), the warp of the substrate after sintering is smaller than the result of the conventional example shown in (a). was confirmed.

This is probably because molybdenum (Mo) and tungsten (W) have different properties against heat such as melting point, and the progress of sintering during firing differs. The melting point of Mo is low compared to that of W. Therefore, Mo has the characteristic of being more easily sintered than W. By forming a metal layer containing Mo having such properties in the peripheral area of the substrate, sintering proceeds faster in the metal layer in the peripheral area during firing, and the shape of the substrate faces downward (that is, opposite to warping). direction). On the other hand, when a metal layer containing W is formed in the outer peripheral area of the substrate, the W layer in the outer peripheral area is difficult to sinter during firing, so the shape of the substrate faces upward (that is, in the same direction as the warp). ).

(Summary of the first embodiment)
As described above, the multi-cavity ceramic substrate 1 according to the present embodiment has the product area 2 in which the plurality of substrate element portions 11 are arranged side by side, and the peripheral area 3 located outside the product area 2. . This multi-cavity ceramic substrate 1 is formed by laminating a plurality of ceramic sheets 21 (for example, ceramic sheets 21a to 21i). On each sheet, any one of the Mo layer 23 for the conductive pattern, the W layer 22 for the conductive pattern, and the wiring 25 for electrolytic plating conduction is formed. A second Mo layer 24 containing molybdenum and not electrically connected to the Mo layer 23 is formed in the peripheral area 3 on the ceramic sheets 21d and 21d on which the Mo layer 23 for the conductive pattern is formed. formed.

According to the above configuration, warping after sintering can be reduced compared to the multi-cavity ceramic substrate 1 on which the second Mo layer 24 is not formed. In other words, the second Mo layer 24 can be said to be a metal layer for suppressing warping that may occur after sintering the substrate. As a result, the rate of occurrence of defective products can be reduced in the multi-cavity ceramic substrate 1 and the ceramic substrate 50 obtained therefrom.

In the above embodiment, the conductive pattern W layer 22 can be rephrased as a metal layer containing tungsten. Also, the Mo layer 23 for the conductive pattern can be rephrased as a first metal layer containing molybdenum. Also, the second Mo layer 24 for improving warpage can be rephrased as a second metal layer containing molybdenum.

[Second embodiment]
In the second embodiment, a configuration in which the shape of the second Mo layer formed in the outer peripheral area is different from that in the first embodiment will be described. FIG. 7 shows a multi-piece ceramic substrate 101 according to the second embodiment. In FIG. 7, the upper left shows the plan configuration of the entire multi-cavity ceramic substrate 101, and the lower right shows an enlarged view of a portion of this multi-cavity ceramic substrate 101 (specifically, the portion surrounded by the dashed line).

A multi-cavity ceramic substrate 101 has a product area (substrate area) 2 including a plurality of substrate element portions 11 and a peripheral area (peripheral area) 3 positioned outside the product area 2 . Except for the shape of the second Mo layer 124 formed in the peripheral area 3, the same configuration as in the first embodiment can be applied to the multi-cavity ceramic substrate 101 . Therefore, only the configuration of the second Mo layer 124 will be described below.

In the multi-cavity ceramic substrate 1 according to the first embodiment, the second slit portion 13 is formed at a predetermined portion of the second Mo layer 24 for warpage reduction. In contrast, in the multi-cavity ceramic substrate 101 according to the second embodiment, the second Mo layer 124 for reducing warpage is not formed with slits.

That is, the second Mo layer 124 formed in the outer peripheral area 3 is formed in a frame shape without gaps so as to surround the entire product area 2 . Such a second Mo layer 124 has a simpler shape than the second Mo layer 24 . Therefore, the second Mo layer 124 can be easily patterned.

When the multi-cavity ceramic substrate 101 is composed of a laminate of ceramic sheets 21 similar to the configuration shown in FIG. and 124e are formed.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims. Also, configurations obtained by combining configurations of different embodiments described herein are also included in the scope of the present invention.

1: Multi-cavity ceramic substrate 2: Product area (substrate area)
3: Peripheral area (peripheral area)
11: substrate element portion 12: slit portion 13: second slit portion 21: ceramic sheet (ceramic layer)
22: W layer (for conductive pattern) (metal layer containing tungsten)
23: Mo layer (for conductive pattern) (first metal layer containing molybdenum)
24: Second Mo layer (for warpage improvement) (second metal layer containing molybdenum)
25: Wiring for electrolytic plating conduction (metal layer for electrolytic plating conduction)
27: Metal plating layer 50: Ceramic substrate 101: Multi-piece ceramic substrate 124: Second Mo layer (for warpage improvement) (second metal layer containing molybdenum)
C1: center line (center position in the width direction of the board element part)
C2: Center line (center position in the width direction of the board element part)

Claims (7)

A multi-cavity ceramic substrate having a substrate region in which a plurality of substrate element portions are arranged side by side and an outer peripheral region located outside the substrate region,
a plurality of ceramic layers;
a first metal layer containing molybdenum formed on at least one of the ceramic layers;
a metal layer containing tungsten formed on at least one of the ceramic layers on which the first metal layer is not formed;
a metal layer for electroplating conduction formed on at least one layer of the ceramic layers,
On at least one of the ceramic layers on which the first metal layer is formed, a second metal layer containing molybdenum and not electrically connected to the first metal layer is provided in the outer peripheral region. is formed and
No metal layer is formed, or no metal layer containing tungsten is formed in the outer peripheral region of the ceramic layer where the metal layer containing tungsten is formed,
Multi-cavity ceramic substrate. 2. The multi-cavity ceramic substrate according to claim 1, wherein said second metal layer is formed in said peripheral region on all of said ceramic layers on which said first metal layer is formed. The substrate element portions are arranged vertically and horizontally in the substrate region,
Slits extending vertically and horizontally are formed in the substrate region for individually partitioning the substrate elements,
3. The multi-cavity ceramic substrate according to claim 1, wherein said second metal layer is not formed on an imaginary extension line of said slit portion in said peripheral region. The second metal layer is provided at a position corresponding to at least a center position in the width direction of the adjacent substrate element portions, and has a diameter equal to or greater than 1/2 of the width of the substrate element portion. 4. The multi-cavity ceramic substrate according to claim 3. A method for manufacturing a multi-cavity ceramic substrate having a substrate region in which a plurality of substrate element portions are arranged side by side and an outer peripheral region positioned outside the substrate region, the method comprising:
a ceramic layer forming step of forming each of a plurality of ceramic layers;
a molybdenum-containing metal layer forming step of forming a first metal layer containing molybdenum on at least one of the ceramic layers formed in the ceramic layer forming step;
a tungsten-containing metal layer forming step of forming a metal layer containing tungsten on at least one of the ceramic layers formed in the ceramic layer forming step;
The molybdenum-containing metal layer forming step and the tungsten-containing metal layer forming step are performed alternatively to each other,
In the molybdenum-containing metal layer forming step, a second metal layer that is not electrically connected to the first metal layer is formed in the outer peripheral region ,
In the tungsten-containing metal layer forming step, no metal layer is formed in the outer peripheral region,
A method for manufacturing a multi-cavity ceramic substrate. The substrate element portions are arranged vertically and horizontally in the substrate region,
Slits extending vertically and horizontally are formed in the substrate region for individually partitioning the substrate elements,
In the molybdenum-containing metal layer forming step, the first metal layer is not formed in the region corresponding to the slit portion, and the second metal layer is formed on the imaginary extension line of the slit portion in the outer peripheral region. do not,
6. The method of manufacturing a multi-cavity ceramic substrate according to claim 5. 7. A method of manufacturing a ceramic substrate, comprising the step of, after manufacturing a multi-cavity ceramic substrate by the manufacturing method according to claim 5 or 6, dividing the multi-cavity ceramic substrate into the individual substrate element portions.

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