JPH1187917A - Ceramic multilayered wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered wiring board for preventing the short-circuit of a wide area metallization layer or the like electrically connected to a via and the wide area metallization layer adjacent through a relatively thin ceramic layer, even when the built-in via is deformed. SOLUTION: For this ceramic multilayered wiring board 1, metal plane layers 10 and 12 which are the wide area metallization layers and a wiring pattern 14 are provided between ceramic layers 2-8 whose thickness is respectively 50 μm, the upper end of via 18 penetrating through in a thickness direction inside the clearance 16 of the wiring pattern 14 is electrically connected with the metal plane layer 12 and an opening part 11 which is almost concentric with the via 18 is formed around a position crossing with the axial direction of the via 18 on the metal plane layer 10 adjacent to the metal plane layer 12 through the ceramic layer 4. Even when the via 18 is expanded or contracted and deformed along the axis by pressing in the thickens direction before baking and a heat contraction difference after the baking by forming the opening part 11, the short-circuit of the metal plane layers 10 and 12 with each other is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic multilayer wiring board formed by laminating a wide metallization layer and a wiring pattern between a plurality of relatively thin ceramic layers.

[0002]

2. Description of the Related Art Generally, in order to obtain a ceramic multilayer wiring board, as shown in FIG.
Metallization paste layers 86 and 88 for a wide area metallization layer and a metallization paste layer for a wiring pattern (not shown), which are spread in substantially the entire plane direction between 2 and 84, are laminated.
In the green sheet 84, the paste layer 88
A via ink metallization 89 is formed to connect the paste layer (not shown) with a paste layer (not shown) in the thickness direction. Then, the green sheets 82 to 84, the metallized paste layers 86 and 88, and the like are laminated, and the obtained laminate 80 is pressed and fired. After firing, the green sheets 82 to 84 are formed into ceramic layers 92 to 94, the metallized paste layers 86 and 88 are formed into wide metallized layers 96 and 98 such as a metal plane layer for power supply, and the ink metallized 89 is formed into vias. The reference numeral 99 indicates a ceramic multilayer wiring board 90.

[0003]

The relative deformation difference due to compression in the thickness direction by a press performed before firing the laminate 80 and the relative heat shrinkage difference after firing,
The following problems may occur. That is, FIG.
As shown in (B), the via 99 expands along its axial direction.
(Extend) and push up a part of the wide area metallization layer 98.
Therefore, the wide area metallized layer 98 and the wide area metallized layer 96 may be short-circuited at a position immediately above the via 99. At this time, the upper surface 9 of the substrate 90 above the via 99
1 may be formed with a convex portion 100 indicated by a broken line.

[0005] As shown in FIG.
9 shrinks along the axial direction, so that a wide area metallization layer 96,
Part of 98 is recessed downward. For this reason, the wide area metallization layer 96 and the wide area metallization layer 98 may come into contact with each other at that position and cause a short circuit. In this case, the wiring board 90
In some cases, a recess 102 is formed in the upper surface 91 of the substrate. These projections 100 and depressions 102 are formed by the ceramic layers 92, 9.
No. 3 tends to appear remarkably as it becomes thinner. The short circuit between the wide area metallization layers 96 and 98 causes the wiring board 9
0 cannot form the original circuit and cannot perform its original function. Further, when the protrusions 100 and the recesses 102 are formed on the upper surface 91 of the substrate 90, there is a problem that electronic components such as IC chips cannot be accurately mounted at the positions. In particular, such a problem is caused when the thickness of the ceramic layer is 60
This was remarkable in a ceramic layer as thin as μm or less.

[0005] The present invention solves the above-mentioned problems of the prior art. Even if the vias are deformed in the axial direction, the wide metallized layers such as the metal plane layers, or the wide metallized layers and the wiring patterns can be formed. It is an object of the present invention to provide a ceramic multilayer wiring board that can prevent a short circuit, can accurately mount an electronic component on an upper surface, and can reduce the thickness of a ceramic layer.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for buffering via deformation in a wide metallized layer or a wide metallized layer adjacent to a wiring pattern via a ceramic layer. Is formed with an idea of forming the opening. That is, the ceramic multilayer wiring board of the present invention is a ceramic multilayer wiring board in which a wide metallization layer and a wiring pattern are formed between a plurality of ceramic layers, and the wide metallization layers are
Alternatively, a via that conducts between the wiring patterns or between the global metallization layer and the wiring pattern in the thickness direction of the substrate, and a wide area adjacent to the global metallization layer or the wiring pattern through which at least one end of the via conducts via a ceramic layer. An opening provided in the wide area metallization layer including a position in the metallization layer that intersects the axial direction of the via.

According to this, even if the via expands or contracts in the axial direction and a part of the wide metallization layer or the like connected to the via is deformed, the deformed part is formed by the opening provided in the adjacent wide metallization layer. Therefore, short circuit between the wide area metallized layers can be prevented. Further, the deformation of the upper surface of the wiring board is reduced by the thickness of the wide metallization layer in the opening, so that the electronic component can be accurately mounted on the upper surface. The present invention also includes a ceramic multilayer wiring board in which the diameter or width of the opening is at least twice the diameter of the via. Here, the reason for making the value twice or more is 2
If the number is less than twice, the prevention of short circuit may be insufficient. According to this, the short circuit can be more reliably prevented.

[0008] Furthermore, a ceramic multilayer in which the thickness of a ceramic layer formed between the wide metallization layer or wiring pattern that is electrically connected to the via and the wide metallization layer adjacent to the wide metallization layer or wiring pattern is 60 μm or less. A wiring board is also included. According to this, even if the ceramic layer is thinned, the short circuit can be easily prevented, so that a multilayer wiring board having more wiring patterns in the thickness direction can be provided. The thickness of the ceramic layer is 60
When the thickness exceeds μm, the short circuit hardly occurs even if the via is deformed. Therefore, the thickness is set to 60 μm or less. Further, a ceramic multilayer wiring board is provided in which the plurality of vias are provided in parallel with and adjacent to each other, and the opening is provided in the wide area metallization layer including each position intersecting with the axial direction of each via. You can also. According to this, the deformation of the wide area metallization layer or the like due to a plurality of vias adjacent to each other is absorbed by one opening, and it is possible to prevent a short circuit between the wide area metallization layer or the like and the adjacent wide area metallization layer.

[0009] Further, the opening may be located at a position intersecting the axial direction of the via in a wide area metallization layer or a plurality of parallel area metallization layers adjacent to the wiring pattern via a ceramic layer to one end of the via. May be ceramic multilayer wiring boards provided respectively. According to this, even if deformation of the wide area metallization layer or the like due to the via is large, a short circuit between two or more wide area metallization layers is prevented in each opening provided in a plurality of wide area metallization layers adjacent to each other with the ceramic layer interposed therebetween. It becomes possible. In this case, the openings are provided at positions substantially concentric with each other. In addition, by making the size of the opening relatively close to the via and the size of the opening separated from the via relatively small, it is possible to prevent short-circuiting and suppress the reduction of the area of the wide area metallization layer.

[0010] Further, the opening may be formed in a wide metallization layer in which both ends of the via are electrically connected or in a wide metallization layer separated from a wiring pattern in a thickness direction of a substrate adjacent to the wiring pattern via a ceramic layer. Ceramic multilayer wiring boards provided so as to include positions intersecting with. According to this, it is possible to prevent a short circuit between the wide area metallized layer or the wiring pattern which is spaced apart in the thickness direction of the substrate due to deformation of both ends of the via, and the wide area metallized layer adjacent thereto via the ceramic layer. It becomes possible.

Further, the opening is provided at a position of the wide metallization layer which is substantially circular or substantially regular polygonal in a plan view and which is substantially concentric with a center axis of the via in a plan view. It is also possible to use a ceramic multilayer wiring board. According to this, it is possible to reliably prevent the short circuit. In this specification, the wide area metallization layer refers to a metal plane layer for a power supply, for example, in which a conductor is laid over substantially the entire surface in a plane direction perpendicular to the thickness direction of the wiring board.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 relates to a ceramic multilayer wiring board 1 of the present invention. As shown in the sectional view of FIG.
This wiring board 1 includes a plurality of ceramic layers 2 serving as insulating layers.
For example, metal plane layers (wide-area metallization layers) 10 and 12 for power supply and a wiring pattern 14 are disposed between the power-supply metal layers. Each of the ceramic layers 2 to 8 has a thickness of 50 μm and is obtained by firing a green sheet mainly containing alumina.
The wiring pattern 14 is made of tungsten (W) or molybdenum (M
This is obtained by firing a paste layer made of a high melting point metal such as o).

A void 16 having a required diameter is formed in the wiring pattern 14, and a via 18 penetrates substantially the center of the void 16 along the thickness direction of the substrate 1. The via 18 has an upper end formed on the lower metal plane layer 12.
, And the lower end (not shown) is connected to another wiring pattern or a wide area metallization layer such as a metal plane layer, and conduction is established between these. The via 18 has a height in the gap 16 between the ceramic layers 6 and 8.
A via cover (not shown) connecting the upper and lower parts is interposed. The gap 16 serves to insulate between the via 18 and the wiring pattern 14 and is formed at the same time when the metal paste layer serving as the wiring pattern 14 is formed by screen printing.

The upper metal plane layer 1 shown in FIG.
The circular opening 11 is formed in the vicinity including the position where the axial direction of the via 18 at 0 crosses. As shown in FIG. 1B, the opening 11 is formed at a position substantially concentric with the via 18 in plan view. The opening 11 is formed at the same time when the metal paste layer that becomes the metal plane layer 10 is formed by screen printing.
By forming such an opening 11, as described above, even when the via 18 expands relatively in the axial direction and pushes up the lower metal plane layer 12, it is indicated by the broken line in FIG. As described above, the raised top portion approaches or enters the opening 11, but does not contact the upper metal plane layer 10. Even when the via 18 contracts relatively in the axial direction and pulls the metal plane layers 12 and 10 downward, as shown by the dashed line in FIG. Since it is the lowest part of the deformed portion in the layer 10, it does not contact the lower metal plane layer 12.

Therefore, in the manufacturing process of the substrate 1, the via 1
No matter which of the above deformations occurs, the upper and lower metal plane layers 10 and 12 do not short-circuit each other as in the conventional case. The diameter of the opening 11 is 0.5 mm, which is five times the diameter of the via 18 of 0.1 mm. The diameter of the opening 11 must be at least twice as large as the diameter of the via 18 in order to prevent the short circuit, and is preferably three times or more. The connection with the via 18 is not limited to the metal plane layer 12, but may be a wiring pattern similar to the wiring pattern 14. The short circuit occurs due to the deformation of the via 18 because the metal plane layer 10 adjacent to the ceramic layer 4 is present.

FIG. 2 relates to different types of openings.
(A) shows a square-shaped opening 20 with rounded corners whose center is substantially concentric with the same via 18 as described above. FIG.
As shown in (B), when the two vias 18 are adjacent to each other in parallel with each other, an oval opening 22 is formed in the metal plane layer 10 so as to surround each via 18 substantially at the center. Further, as shown in FIG. 2 (C), in a similar case, two circular portions
An opening 24 in the form of a cocoon may be formed by connecting 6 and 26.

In particular, like the opening 24, each via 1
By utilizing the circular portion 26 having the center at approximately 8,
This is desirable because the short circuit can be prevented without significantly reducing the area of the metal plane layer 10. When three or more vias 18 are adjacent to each other in parallel with each other, a modified oval opening following the opening 22 or FIG.
It is desirable to form an opening 28 having a substantially L-shape as shown in (D), or an opening having a deformed shape such as a substantially L-shape utilizing the above-mentioned circular portion 26 or a substantially rectangular shape.

FIG. 3 relates to a different form of ceramic multilayer wiring board. The wiring board 30 shown in FIG. 3A has three ceramic layers 31 to 35 each having a thickness of 50 μm.
Metal plane layers (wide area metallization layers) 36 to 38 and wiring patterns 39 are provided. The upper end of the via 41 penetrating vertically through the space 40 of the wiring pattern 39 is
It is electrically connected to the third metal plane layer 38 from the top. The lower end of the via 41 is electrically connected to a wiring pattern (not shown) or a metal plane layer. Also, 1 from the top
Circular openings 42 and 43 are formed concentrically with the via 41 in the vicinity including the position intersecting the axial direction of the via 41 in the layers and the second metal plane layers 36 and 37. In this case, the diameter of the opening 43 close to the via 41 is set relatively smaller than that of the opening 42 remote from the via 18. However, the diameter of the opening 43 is twice or more the diameter of the via 41.

In the manufacturing process of the wiring board 30, when the via 41 relatively expands along the axial direction, even if the metal plane layer 38 is pushed up, as shown by a broken line in FIG. The ascending top part is the opening 43
Approximately stays near. Even if the opening 43 rises conically upward, the upper end of the deformed portion remains near the opening 42 of the uppermost metal plane layer 36. Therefore, the three metal plane layers 36 to 38
No short circuit is caused between them. on the other hand,
In the manufacturing process of the wiring board 30, when the via 41 relatively shrinks along its axial direction, the third metal plane layer 38 from the top is pulled downward as shown by the dashed line in the figure. Then, the opening 43 that is the lowermost end of the deformed portion in the second metal plane layer 37 remains above the recess of the plane layer 38. In addition, since the opening 42 of the uppermost metal plane layer 36 has a larger diameter than the opening 43, it hardly deforms downward.

Therefore, by forming the openings 42 and 43, even in the wiring board 30 in which the three metal plane layers 36 to 38 are adjacent to each other, a short circuit between them can be reliably prevented. Moreover, since the flatness of the upper surface 30a of the wiring board 30 is also maintained, various electronic components can be accurately mounted on the upper surface 30a. The opening 4
Conversely, even if the diameter of the opening 42 is smaller than that of the opening 43, the short circuit can be prevented in correspondence with the case where the via 41 contracts in the axial direction. Further, the opening 43 close to the via 41 may be circular, and the other opening 42 may be non-circular such as a regular polygon. Furthermore, three or more openings can be formed in each metal plane layer so as to be substantially concentric along the thickness direction of the wiring board. In addition, via 41
The metal plane layer 38 that is electrically connected to the wiring pattern 39
Even with a wiring pattern similar to that described above, the above short circuit can be prevented.

FIG. 3B shows another ceramic multilayer wiring board 4.
Regarding 5. The substrate 45 has a thickness of 50 μm from above.
m ceramic layers 46-48, 49a-49e, 48 '
46 ′, and two metal plane layers 54, 56 and 56 ′, 54 ′ (wide metallization layer) above and below, and six wiring patterns 50a to 50f in the thickness direction. The layers are stacked vertically symmetrically. A void 51 formed at a predetermined position of each of the wiring patterns 50a to 50f
A via 52 penetrates the inside. The upper and lower ends of the via 52 are connected to upper and lower metal plane layers 56 and 56 ', and these are electrically connected to each other.

The uppermost and lowermost metal plane layers 5
In the vicinity including the position at which the via 52 intersects with the axial direction of the via 52, circular openings 58, 58 ′ that are substantially concentric with the via 52 in plan view are formed. Since the vias 52 are long along the thickness direction of the wiring board 45, the vias 52 are pressed at the time of pressing before firing or the ceramic layers 49 after firing.
Due to the difference in shrinkage from a to 49e, expansion and shrinkage tend to occur along the axial direction. For example, when the via 52 relatively expands in the axial direction, the upper and lower metal plane layers 56 and 56 'are pushed up and down as shown by broken lines in the figure. However, the uppermost and lowermost ends of this deformed portion are each opening 5
Stay near 8,58 '. Therefore, the upper metal plane layers 54 and 56 and the lower metal plane layers 54 'and 56' do not short-circuit with each other.

On the contrary, when the via 52 is relatively contracted along the axial direction, the upper and lower metal plane layers 56 and 56 'which are electrically connected to the via 52 are also located on the center side, as shown by the dashed line in the figure. Pulled. Accordingly, the uppermost and lowermost metal plane layers 54 and 54 'are similarly deformed. However, since the openings 58 and 58' are formed in the respective deformed portions, no short circuit occurs as described above. In addition, even if the via 52 is deformed by the opening 58, a convex portion or a dent is not easily formed on the upper surface 54 a of the wiring board 45. Therefore, it is also possible to accurately fix electronic components such as an IC chip mounted on the upper surface 54a. It should be noted that the same effects as described above can be obtained even if the metal plane layers 56 and 56 ′ that conduct vertically with the via 52 are changed to the wiring pattern 50 n.

The present invention is not limited to the embodiments described above. For example, as shown in FIG. 4, wide metallization layers 66 and 68 are provided in the middle of a plurality of ceramic layers 61 to 65, and wiring patterns 70 and 7 are formed above and below them.
Also, the present invention is applied to a ceramic multilayer wiring board 60 in which the components 4 are arranged and laminated. Vias 72 and 76 are connected to the wide area metallization layers 66 and 68 from above or below, and are electrically connected to a wide area metallization layer and the like (not shown). Each via 72, 76
Are the voids 71, 7 formed in the wiring patterns 70, 74.
5 vertically penetrates substantially the center.

A circular opening 67 is formed in the vicinity of the upper wide metallization layer 66 including a position intersecting with the axial direction of the lower via 76, and the lower wide metallization layer 68 is provided.
A circular opening 69 is formed in the vicinity including the position intersecting the axial direction of the upper via 72 in FIG.
Therefore, as shown by a broken line and a dashed line in the figure, each via 7
Even if the first and second members 76 expand and contract in the same manner as described above, the wide area metallized layers 66 and 68 which are parallel to each other form the respective openings 67 and
9 prevents short circuits between each other. It is apparent that even if one of the wide metallization layers 66 and 68 is a wiring pattern, a short circuit between the two can be prevented by forming an opening in the other wide metallization layer.

The ceramic layer in the multilayer wiring board is not limited to the above-mentioned alumina, but may be aluminum nitride, glass ceramic, mullite, or the like. Furthermore,
The material of the wide area metallization layer and the wiring pattern is also W or Mo.
Not limited to, Cu and Co and alloys based on these,
Mo-Mn, Ag, Ag-Pd, Ag-Pt, or the like can also be applied. Further, the multilayer wiring board of the present invention includes a pin grid array type wiring board having pins implanted on the upper / lower surfaces thereof, and a surface mount type wiring board such as a multi-chip module having a plurality of electronic components and elements mounted on the upper surface. Is also included. Further, the electronic components mounted on the upper surface may be mounted with elements such as transistors, diodes, and EFTs in addition to the IC chip.

[0027]

According to the ceramic multi-layer wiring board of the present invention, even if the built-in via is deformed to expand or contract in the axial direction, the ceramic layer is formed on the wide metallization layer or the wiring pattern through which the via is conducted. Since the openings are formed at predetermined positions of the wide metallization layers adjacent to each other, the wide metallization layers or the wiring pattern and the wide metallization layers do not contact each other to cause a short circuit.
In particular, since the short circuit can be prevented even when a thin ceramic layer is used, a high-density ceramic multilayer wiring board having more wiring patterns in the thickness direction can be easily obtained. Also, even if the via is deformed, the formation of the opening suppresses the occurrence of a protrusion or a dent on the upper surface of the wiring board, so that an electronic component such as an IC chip is accurately mounted on the upper surface. It is also possible to do.

[Brief description of the drawings]

FIG. 1A is a partial vertical sectional view showing one embodiment of a ceramic multilayer wiring board of the present invention, and FIG. 1B is a sectional view taken along line BB in FIG.

FIGS. 2A to 2D are cross-sectional views similar to FIG. 1B, each showing an opening in a different form.

FIGS. 3A and 3B are partial vertical sectional views showing different forms of ceramic multilayer wiring boards.

FIG. 4 is a partial vertical sectional view showing a ceramic multilayer wiring board of still another form.

FIG. 5 (A) is a partial vertical sectional view showing a conventional multilayer body and a ceramic multilayer wiring board obtained by firing the same, and FIGS. 5 (B) and (C) are partial vertical sectional views showing their deformed states.

[Explanation of symbols]

1,30,45,60 ………………………………………
Multilayer wiring board 2,4,6,8,31-35,46-49,61-65 ...
Ceramic layer 10,12,36-38,54,56,66,68 ……………
Wide area metallization layer 11,20-28,42,43,58,58 ', 67,69 ...
… Openings 14,39,50a to 50f, 70,74 …………………
Wiring pattern 18,41,52,72,76 ………………………………
Via

Claims (3)

[Claims] 1. A ceramic multilayer wiring board in which a wide metallization layer and a wiring pattern are formed between a plurality of ceramic layers, wherein the wide metallization layers, the wiring patterns, or the wide metallization layer and the wiring pattern are formed. A via that conducts in the thickness direction of the substrate between the via, and a position that intersects the axial direction of the via in a global metallization layer or a global metallization layer adjacent to the wiring pattern via a ceramic layer at least one end of the via passes through the ceramic layer. And an opening provided in the wide area metallization layer. 2. The ceramic multilayer wiring board according to claim 1, wherein the diameter or width of the opening is at least twice the diameter of the via. 3. A wide metallized layer or wiring pattern which is electrically connected to the via, and a ceramic layer formed between the wide metallized layer or the wide metallized layer adjacent to the wide metallized layer or wiring pattern has a thickness of 60 μm or less. The ceramic multilayer wiring board according to claim 1 or 2, wherein: