JPH0715144A - Ceramic multilayer printed circuit board for multi-chip module - Google Patents

Abstract

PURPOSE:To provide a ceramic multilayer printed circuit board for multi-chip module preventing warpage of the printed circuit board on baking. CONSTITUTION:In a circular title printed circuit board, a conductive metal layer for constituting an internal wiring pattern 2 is provided and the area ratio of a formation region 3 of the internal wiring pattern 2 for a printed circuit board area is 80% or less. A conductive metal layer dummy pattern 4 is provided at the outer-periphery side of the internal wiring pattern 2.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a ceramic multilayer substrate for a multi-chip module (MCM).

[0002]

2. Description of the Related Art Semiconductor chips are usually used by being packaged with a plastic material, a ceramic material or the like for the purpose of protection from the external environment and improvement of handleability. For such a semiconductor package, for example, a ceramic multilayer substrate is used.

By the way, recently, in the case where a module is composed of a plurality of semiconductor chips due to the increase in operating speed of semiconductor chips (increasing operating frequency), each chip is individually packaged, and Since signal transmission between chips is performed via the circuit board, good operating characteristics are achieved because the signal transmission path becomes long and the ratio of the wiring layer having a relatively high resistance value on the surface of the circuit board increases. There is a problem that it cannot be obtained, that is, it cannot cope with high-speed operation of a semiconductor chip. Therefore, for example, a so-called multi-chip module (hereinafter, referred to as MC, in which a plurality of semiconductor chips are mounted on a ceramic multilayer substrate and signals are transferred between the chips by an internal wiring layer).
M) is drawing attention.

In such an MCM, for example, as shown in FIG. 4, a disk-shaped ceramic multilayer substrate 1 having a diameter of 5 inches, in which an internal wiring layer 2 is provided, is formed on a part of the MCM. It is manufactured by bonding and arranging Cu and Al inter-chip wiring parts and mounting a plurality of semiconductor chips thereon. An actual MCM is used by cutting out a necessary portion, that is, a portion having the internal wiring layer 2 from the disc-shaped ceramic multilayer substrate 2.

[0005]

[Problems to be Solved by the Invention] MCM as described above
The ceramic multi-layer substrate for use has a disk-like shape with a diameter of 5 inches or more to allow it to flow to the mounting line, etc., but the part actually used, that is, the part with the internal wiring layer is the substrate. Since it is quite small with respect to the area, various problems occur.

For example, an MCM multilayer substrate is also manufactured in the same manner as a normal ceramic multilayer substrate. Specifically, a ceramic green sheet on which a conductor paste is printed is laminated according to a desired wiring pattern, and the laminated body is fired to simultaneously fire the ceramic green sheet and the conductor paste. However, in the ceramic multi-layer substrate for MCM, the printed area of the conductor paste is considerably smaller than the substrate area. Therefore, the shrinkage behavior during firing differs between the portion with the printed layer of the conductor paste and the portion without the printed layer. There is a problem that a large warp occurs in the substrate after the baking. This problem becomes particularly noticeable when the internal wiring layer has a polygonal shape.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a ceramic multilayer substrate for a multi-chip module capable of preventing the substrate from warping during firing.

[0008]

A ceramic multilayer substrate for a multi-chip module of the present invention has a conductive metal layer forming an internal wiring pattern, and the area ratio of the internal wiring pattern forming region to the substrate area is 80%. In the circular ceramic multilayer substrate for a multi-chip module having a percentage of not more than%, a dummy pattern of a conductive metal layer is provided on the outer peripheral side of the formation region of the internal wiring pattern.

[0009]

In the ceramic multilayer substrate for a multi-chip module of the present invention, the dummy pattern is provided on the outer peripheral side of the area where the internal wiring pattern is formed. In this way, by providing the dummy pattern, it is possible to make the shrinkage behavior of the portion having the internal wiring pattern of the ceramic multilayer substrate and that of the outer peripheral portion thereof substantially equal, so that it is possible to reduce the warpage during firing. Becomes Further, in actual use, since the portion including the formation area of the internal wiring pattern is cut out and used, the dummy pattern on the outer peripheral side does not adversely affect the characteristics and the like.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a diagram showing the construction of an embodiment of a ceramic multilayer substrate for a multi-chip module of the present invention, in which (a) is its transverse section and (b) is its longitudinal section. is there. In the ceramic multilayer substrate 1 for MCM shown in the figure, an internal wiring pattern 2 is provided near the center inside thereof. The internal wiring pattern 2 includes a signal wiring layer (including through holes), a power supply layer, a ground layer, etc., and is formed from a firing layer of a conductor paste co-fired with the ceramic multilayer substrate 1, that is, a conductive metal layer. It will be. Since the ceramic multilayer substrate 1 of this embodiment is used to finally manufacture a rectangular MCM, the internal wiring pattern 2 has a quadrangular shape.

A dummy pattern 4 of a conductive metal layer is formed on the outer peripheral side of the formation region 3 of the internal wiring pattern 2. The dummy pattern 4 is the internal wiring pattern 2.
The pattern is set so as to surround the formation region 3 of No. 1 and the non-formation region 5 is formed between the conductive metal layers forming the dummy pattern 4.
In this way, by providing the non-formed region 5 of the conductive metal layer, it is possible to secure the adhesive force between the respective layers of the ceramic multilayer substrate 1.

In the ceramic multilayer substrate 1 for MCM shown in FIG. 1, on the outer peripheral side of the formation region 3 of the internal wiring pattern 2,
By providing a plurality of ring-shaped dummy patterns 4 concentrically, a region 5 in which a conductive metal layer is not formed, that is, a joint between ceramic layers is provided between the dummy patterns 4. The non-formed region 5 of the conductive metal layer is formed, for example, in FIG.
It is possible to further increase the number by dividing the ring-shaped dummy pattern 4 into a plurality as shown in FIG.
Further, as shown in FIG. 3, the ring-shaped dummy pattern 4 is formed.
It is also possible to form the non-formed region 5 of the conductive metal layer by providing a white portion (non-printed portion of the conductor paste) 6 therein.

In the ceramic multi-layer substrate 11 for MCM as described above, the required number of ceramic green sheets constituting the same are prepared, and when the conductor paste is printed on the green sheets according to the internal wiring pattern 2, the dummy pattern 4 is used. At the same time, print the conductor paste. Then, after stacking such green sheets, firing is performed under the conditions according to the ceramic green sheets used, and the ceramic layers of the multilayer substrate and the conductive material to be the internal wiring pattern and dummy pattern are simultaneously fired. It is made.

In the MCM ceramic multilayer substrate 11 of the above-described embodiment, the rectangular internal wiring pattern 2 is used.
Since the dummy pattern 4 of the conductive metal layer is provided so as to surround the outer peripheral side of the formation region 3 of the, the ceramic portion corresponding to the formation region 3 of the internal wiring pattern 2 and the ceramic portion on the outer peripheral side thereof are formed. The shrinkage behavior during firing can be made almost the same. This makes it possible to prevent warpage of the ceramic multilayer substrate 1 during simultaneous firing. In particular, when the formation region 3 of the internal wiring pattern 2 has a polygonal shape such as a quadrangular shape, warpage becomes remarkable, so that the formation of the dummy pattern 4 is effective. The shape of the formation region 3 of the internal wiring pattern 2 is not limited to a quadrangular shape, and the effect of the present invention can be obtained even if the shape is a circle or a similar shape, but particularly in the case of a polygonal shape such as a quadrangle. The present invention is effective.

Further, since the non-formation region 5 is provided between the conductive metal layers for the dummy pattern 4, the adhesion failure between the ceramic layers does not occur. Further, when the ceramic multilayer substrate 1 for MCM is actually used, since the portion including the formation region 3 of the internal wiring pattern 2 is cut out and used, the dummy pattern 4 on the outer peripheral side thereof does not adversely affect the characteristics and the like.

The constituent material of the ceramic multilayer substrate 1 is not particularly limited, and aluminum nitride,
Various ceramic materials such as silicon nitride and aluminum oxide can be applied. Also, internal wiring pattern 2
The area ratio of the formation region 3 to the substrate area is 80% or less. When the above area ratio exceeds 80%, warpage does not become a problem. In other words, the effect of the dummy pattern 4 can be remarkably obtained when the area ratio of the formation region 3 of the internal wiring pattern 2 to the substrate area is 80% or less.

Next, a specific example of the ceramic multilayer substrate for MCM according to the above-mentioned embodiment and the evaluation result thereof will be described.

Example 1 A rectangular AlN green sheet obtained by sheet forming was subjected to formation of predetermined through holes and filling of the conductive paste into the through holes, and then the internal wiring pattern 2 shown in FIG. The conductor paste was pattern-printed so that the dummy pattern 4 was formed.

Next, a desired number of AlN green sheets are laminated, processed into a circular shape, degreased, and dried in a nitrogen atmosphere.
Firing was performed at 00 to 1900 ° C. to obtain an intended aluminum nitride multilayer substrate for MCM. The area ratio of the formation region 3 of the internal wiring pattern 2 to the substrate area in this embodiment is about 50%.

When the amount of warpage of the thus obtained aluminum nitride multilayer substrate for MCM was measured, the amount of warpage was 0.0
It was 1 mm / cm or less, and it was confirmed that a sound aluminum nitride multilayer substrate was obtained.

Comparative Example 1 An aluminum nitride multilayer substrate for MCM was produced in the same manner as in Example 1 except that the conductor paste was printed only on the internal wiring pattern (no dummy pattern was printed). The warp amount of this aluminum nitride multilayer substrate for MCM was 2 mm / cm or more, which was impractical.

[0023]

As described above, according to the present invention, it is possible to provide a sound ceramic multi-layer substrate for MCM with good reproducibility by forming a dummy pattern with almost no warpage.

[Brief description of drawings]

FIG. 1 is a diagram showing a ceramic multilayer substrate for MCM according to an embodiment of the present invention, in which FIG.
(B) is a longitudinal sectional view.

FIG. 2 is a diagram showing a modified example of a dummy pattern.

FIG. 3 is a diagram showing another modification of the dummy pattern.

FIG. 4 is a view showing a conventional ceramic multilayer substrate for MCM.

[Explanation of symbols] 1 ... Ceramic multilayer substrate for MCM 2 ... Internal wiring pattern 3 ... Internal wiring pattern formation area 4 ... Dummy pattern 5 ... Dummy conductive metal layer non-formation area

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H05K 3/46 Z 6921-4E

Claims (2)

[Claims] 1. A circular ceramic multi-layer substrate for a multi-chip module, comprising a conductive metal layer forming an internal wiring pattern, wherein an area ratio of a region for forming the internal wiring pattern to a substrate area is 80% or less, A ceramic multilayer substrate for a multi-chip module, wherein a dummy pattern of a conductive metal layer is provided on the outer peripheral side of the area where the internal wiring pattern is formed. 2. The ceramic multilayer substrate for a multi-chip module according to claim 1, wherein the dummy pattern has a region where the conductive metal layer is not formed. .