JP3216940B2 - Multi-chip module assembly board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mounting a plurality of LSI bare chips on a small high-density wiring board and mounting the module on a printed circuit board. And a multi-chip module assembly board.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional multi-chip module substrate of this kind has bare chips 21 and 22 such as LSI chips mounted on a fine wiring multilayer substrate 20 composed of a ceramic substrate, a silicon substrate or the like. Then, a method of mounting on a printed board using a lead array 23 arranged on the outer peripheral portion of the board is adopted.

However, in such a method, even if the multi-chip module board is mounted at a high density, the circuit formation limit and the connection limit on the printed board side are limited at the connection portion with the printed board. However, it has been difficult to form a high-density mounting wiring board as a whole.

[0004] Further, it is also difficult to match the impedance at the connection portion, so that it has been difficult to achieve high speed in the entire mounting system.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-chip module assembly board for suitably solving the problems associated with the conventional multi-chip module board mounting as described above.

For this reason, in the multi-chip module assembly board of the present invention, a plurality of LSI bare chips are mounted on a small high-density wiring board, and a plurality of LSI bare chips are mounted on a printed board. multichip modules - has Le substrate, the one of the multi-chip module - in Le substrate at least one layer of circuit wiring patterns - down its insulating base - bent to the outside together with the scan material freely extended to other multi It is configured to be continuously connected to a part of the circuit wiring pattern of the chip module substrate.

Here, it is preferable that the means for continuously connecting the multi-chip module boards be constituted by a flexible circuit board.

[0008]

FIG. 1 is a sectional view conceptually showing a multi-chip module assembly board according to an embodiment of the present invention.
The figure shows an example in which two multi-chip module substrates A and B each having four circuit wiring conductor layers are interconnected.

That is, the circuit wiring pattern 1 of the first layer in one multi-chip module substrate A extends to the outside as a flexible circuit board 7 and the other multi-chip module
And is continuously connected to the circuit wiring pattern 2 of the second layer on the substrate B. Solder bumps 3 for mounting an LSI bare chip are formed on the uppermost layers of these substrates A and B, respectively.

The conductor layers of the two substrates A and B are electrically connected by via holes 4 to form a high-density three-dimensional circuit. A heat radiating plate 6 having cooling fins 5 for effectively radiating the heat generated from the LSI bare chips mounted at high density is provided at the bottom of both substrates A and B.

FIG. 2 shows an example of a device mounted state of a multi-chip module assembly board according to an embodiment of the present invention. An LSI bare chip 8 is mounted on each of the multi-chip module boards A, B and C. Further, since the flexible circuit board 7 for connecting the multi-chip module boards A, B, and C is rich in flexibility, the flexible circuit board is used as shown in FIG. It can be folded and laminated at the portion of the substrate 7 and compactly mounted on the device.

[0012]

According to the multi-chip module assembly board of the present invention, each multi-chip module board is connected.
The bendable circuit wiring pattern layer is formed integrally with the circuit wiring pattern that constitutes the multi-chip module substrate, so no space is required for connection and the size is reduced. Can be achieved.

Therefore, there is no possibility that the distance between the mounted LSI bare chips is shortened and that the speeding up of the substrate obtained by the modularization is not impaired.

Further, while the reliability of connection between the multi-chip module substrates can be improved, mounting such as folding and stacking is possible, which greatly contributes to miniaturization of electronic equipment.

[Brief description of the drawings]

FIG. 1 is a sectional configuration view conceptually showing a multi-chip module assembly board according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a device mounted state of a multi-chip module aggregate board according to an embodiment of the present invention.

FIG. 3 is a view showing a conventional multi-chip module substrate.

[Explanation of symbols]

 Reference Signs List A Multi-chip module board B Multi-chip module board 1 Circuit wiring pattern 2 Circuit wiring pattern 3 Solder bump 4 Via hole 5 Cooling fin 6 Heat sink 7 Flexible circuit board 8 LSI bare chip 9 Spacer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 25/00

Claims (2)

(57) [Claims] A multi-chip module substrate for mounting a plurality of LSI bare chips on a small high-density wiring board and mounting the module on a printed circuit board. At least one circuit wiring pattern on the multi-chip module substrate is extended to be able to bend to the outside together with the insulating base material, and a circuit wiring pattern of a part of another multi-chip module substrate is provided. A multi-chip module assembly board configured to be continuously connected to a component. 2. The multi-chip module assembly board according to claim 1, wherein said means for continuously connecting said multi-chip module boards is formed of a flexible circuit board.