JPH09283875A - Printed wiring substrate for mcm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a MCM substrate capable of separately measuring electric characteristics of each semiconductor element mounted on a MCM(multi-chip module) substrate, and of thereby simply inspecting an electric connection between each semiconductor element and the MCM substrate. SOLUTION: Power sources (potential wire, grounding wire) 3 formed in a MCM substrate 1 are stuctured as respectively electrically independent power sources 3a, 3b corresponding to a plurality of semiconductor elements 2a, 2b mounted. Electrical characteristics of internal diodes 5a, 5b of each of semiconductor element 2a, 2b can come to be measured every semiconductor element using an inspection pad 8, a connection condition between each of the semiconductor elements 2a, 2b and a wire 4 can come to be inspected using the measured electrical characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-chip module (MC which mounts a plurality of semiconductor elements on one substrate.
M: Multi Chip Module), and more particularly to a printed wiring board for MCM in which a power supply circuit connected to each semiconductor element is improved.

[0002]

2. Description of the Related Art With the recent high integration of semiconductor devices, the use of MCMs in which a plurality of semiconductor elements are integrally mounted on a single printed wiring board is increasing. In this MCM, usually, various components including semiconductor elements are mounted on a substrate (hereinafter referred to as an MCM substrate) on which a required pattern wiring is formed by a printed wiring technique in advance, and the various components are electrically connected to the pattern wiring. ing. In this pattern wiring, power supply wirings and ground wirings (hereinafter collectively referred to as power supply wirings) connected to each semiconductor element are integrally formed and made common, and an external connection terminal is provided in a part of this power supply wiring. It is provided so that power is supplied to each semiconductor element through the external connection terminal.

[0003]

SUMMARY OF THE INVENTION Such conventional MC
In M, once a plurality of semiconductor elements are mounted on the MCM substrate, the respective semiconductor elements are electrically connected to each other through the common power supply wiring, so that the individual semiconductor elements and M
There is a problem that it becomes difficult to inspect the electrical connection with the CM board. The reason is that, as a method of electrically inspecting the connection between the semiconductor element and the MCM board, usually, the characteristics of the protection diode interposed between the input / output terminal of the semiconductor element and the input / output buffer circuit can be measured. Although generally performed, in the MCM substrate having the common power supply wiring as described above, the protection diodes of the plurality of semiconductor elements are connected in parallel via the power supply wiring,
It becomes impossible to measure the electrical characteristics of each protection diode independently. Therefore, due to variations in the protection diode characteristics of each semiconductor element, the semiconductor element and MCM
This is because it is difficult to determine the quality of the connection between the boards.

An object of the present invention is to enable the electrical characteristics of each semiconductor element mounted on an MCM board to be individually measured, thereby facilitating the inspection of the electrical connection between each semiconductor element and the MCM board. An object of the present invention is to provide an MCM substrate that can be manufactured.

[0005]

The MCM substrate of the present invention comprises:
The power supply wiring formed on the MCM substrate and connected to the plurality of semiconductor elements mounted on the MCM substrate is electrically independent for each semiconductor element. Here, the power supply wiring includes a wiring to which a required potential is supplied and a ground wiring facing the wiring, and at least a part of the power supply wiring is electrically independent of each other corresponding to the plurality of semiconductor elements. There is. In this case, it is preferable that the power supply wiring is individually formed in the region where each semiconductor element is mounted. Further, it is preferable that the respective power supply wirings are configured so that they can be electrically connected to each other by connection lines.

[0006]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view schematically showing an embodiment of the present invention, and FIG. 2 is a schematic sectional configuration diagram thereof. The MCM board 1 is formed as a multilayer printed wiring board in which an insulating layer and a wiring layer are formed in multiple layers by, for example, a ceramic lamination technique, and the power supply wiring 3 is configured by using a part of the multilayer wiring layer. are doing. Further, a plurality of semiconductor elements 2, in this embodiment, two semiconductor elements 2a and 2b are mounted on the MCM substrate 1, and the M
The surface wiring 4 formed on the surface of the CM substrate 1 is surface-mounted, and the surface wiring 4 is electrically connected.
The surface wirings 4 have a pattern configuration in which signal wirings and power supply wirings are mixed, and are connected to external terminals (external leads) provided in each semiconductor element 2 by soldering or the like.

Here, the power supply wiring 3 is provided for each of the semiconductor elements 2a and 2b.
And are electrically independent of each other. In this embodiment, each power supply wiring 3a, 3b
Are formed so as to occupy as large an area as possible in the regions surrounding the corresponding semiconductor elements 2a and 2b. Then, the power supply wirings 3a and 3b are respectively connected to the portions 4a and 4 of the surface wiring 4 through the through holes 6a and 6b.
b is individually connected to the semiconductor elements 2a and 2b through the surface wirings 4a and 4b.

Therefore, the MCM configured as described above
In the substrate 1, the power supply wirings 3a and 3b corresponding to the semiconductor elements 2a and 2b are electrically independent at least in the state where the semiconductor elements 2a and 2b are mounted. The built-in protection diodes 5a and 5b are electrically independent from each other, and are not connected in parallel via the power supply wiring 3. Therefore, for example, the connection state between the connection terminal 7a provided in the semiconductor element 2a and the wiring of the MCM substrate 1 is determined by the inspection pad 8 on the surface wiring 4 and the power supply wiring 3a to be connected to the connection terminal 7a. The inspection can be performed by measuring the electrical characteristics of the protection diode 5a of the semiconductor element 2a existing between the two. Similarly, the connection state of the connection terminal 7b having the semiconductor element 2b can be inspected by measuring the characteristics of the protection diode 5b existing between the inspection pad 8 on the surface wiring 4 and the power supply wiring 3b.

After the inspection of the wiring state is completed, the power source wirings 3a and 3b, which are independent of each other, are connected by the bridge wiring 9 or the like to complete the MCM substrate 1.
Two common power supply lines 3 will be configured,
Similar to the conventional MCM board, the power supply connection to the MCM board is realized by connecting an external power supply circuit to this power supply wiring.

In the present invention, the power supply wiring of the above embodiment is a power supply wiring to which a required potential is supplied,
Alternatively, it may be applied to at least one of the ground wirings forming a pair therewith. However, by configuring all the power supply wirings including the ground wirings independently as described above, it becomes possible to inspect the connection state at various terminals of the mounted semiconductor element in more detail.

Further, in the above-mentioned embodiment, an example in which two semiconductor elements are mounted is shown, but it goes without saying that the present invention can be similarly applied to the case where three or more semiconductor elements are mounted. Needless to say, the patterns of the power supply wirings formed independently of each other are not limited to those in the above-described embodiment.

[0012]

As described above, according to the present invention, the power supply wiring provided on the MCM substrate is electrically independent of each other to correspond to a plurality of semiconductor elements. , In particular, it becomes possible to independently measure the electrical characteristics of the built-in protection diode,
It is possible to easily inspect the electrical connection state between each semiconductor element and the wiring of the MCM board, and high quality MCM
Will be extremely useful in constructing.

[Brief description of drawings]

FIG. 1 is a plan view schematically showing an embodiment of an MCM substrate of the present invention.

FIG. 2 is a schematic cross-sectional view of FIG.

[Explanation of symbols]

 1 MCM substrate 2 (2a, 2b) Semiconductor element 3 (3a, 3b) Power supply wiring 4 (4a, 4b) Surface wiring 5a, 5b Protection diode 6a, 6b Through hole 7a, 7b Connection terminal 8 Inspection pad

Claims (4)

[Claims] 1. In a printed wiring board for a multi-chip module (MCM) in which a plurality of semiconductor elements are mounted on a single board, power supply wirings connected to the respective semiconductor elements are electrically connected to the respective semiconductor elements. Printed wiring board for MCM, which is characterized in that it is independent. 2. The power supply wiring includes a wiring to which a required potential is supplied and a ground wiring facing the wiring, and at least a part of the power supply wiring corresponds to a plurality of semiconductor elements and is electrically independent of each other. The printed wiring board for MCM according to claim 1. 3. The MC according to claim 1, wherein the power supply wiring is individually formed in a region where each semiconductor element is mounted.
Printed wiring board for M. 4. The printed wiring board for an MCM according to claim 1, wherein each power supply wiring is configured to be electrically connectable to each other by a connecting wire.