JPH06216477A - Wiring board and electronic circuit device using the same - Google Patents

Abstract

PURPOSE:To perform a wiring operation and a high-speed transmission operation with good efficiency even when a signal is transmitted by a differential signal. CONSTITUTION:In a multilayer printed-circuit board 1, an LSI 2 is mounted and wiring patterns connected to package pins 3 for the LSI 2 are formed at least on one face. In the printed-circuit board, the pattern for a line handling a differential signal or a power supply is formed as a two-layer laminated wiring pattern constituted of many layers in such a way that an insulating layer 6 is sandwiched between a metal layer 5 and a metal layer 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for mounting an electronic component such as an LSI and a device using the same, and more particularly to a technique effective for performing signal transmission in a differential format. Is.

[0002]

2. Description of the Related Art There is a multilayer printed circuit board technique as a means for increasing the density of electronic circuit packaging. Regarding this technology,
For example, as described in "Printed Circuit Board Technology and Its Quality Assurance" published by Applied Technology Publishing Co., Ltd., pages 277 to 279, it has a multilayer metal wiring structure in which an inner layer substrate and an outer layer substrate are bonded together, and through holes are formed between outer layers. A typical configuration is to connect layers by technology.

By the way, for example, when mounting an LSI,
As signal transmission between them, single-ended signal transmission has been conventionally used. However, single-ended (each consisting of one signal line and ground line)
Signal transmission due to is susceptible to noise. Therefore,
It is conceivable to use a differential signal transmission method (comprising a ground line, one positive signal line and one negative signal line), which is excellent in high speed and noise resistance.

[0004]

According to a study by the present inventor, when handling a differential signal, two signal lines are required for one signal, and therefore wiring related to signals on a printed circuit board is required. Is doubled, and there is a problem that the wiring efficiency on the substrate deteriorates.

Therefore, an object of the present invention is to provide a technique capable of performing efficient wiring and high-speed transmission even if signal transmission is performed by a differential signal.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0007]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, an electronic component such as an IC is mounted, and a wiring pattern connected to pins of the electronic component is formed on at least one surface, and the wiring pattern is mutually insulated in the thickness direction. Thus, at least two layers are formed.

[0009]

According to the above-mentioned means, by forming the signal line or the power supply line in at least two layers, the differential signal has a function equivalent to that of the twisted pair cable while the area of the wiring pattern for one line is sufficient. The differential signal can be transmitted.

Therefore, it is possible to perform high-speed transmission while eliminating the influence of noise without lowering the packaging density.

[0011]

First Embodiment FIG. 1 is a side view showing a wiring board according to the present invention.

A QFP (Quad Flat Packa) is provided on top of the multilayer printed circuit board 1 (which is not limited to a multilayer).
A two-layer laminated wiring pattern 4 for connecting to the package pin 3 of the g) type LSI 2 is formed. The two-layer laminated wiring pattern 4 has the same pattern shape with the first metal layer 5 formed on the surface of the substrate and the insulating layer 6 for electrically insulating the upper and lower sides interposed therebetween. Metal layer 7
Are formed in a stacked state.

The package pin 3 has a two-layer structure so that it can be connected to the two-layer laminated wiring pattern 4, and strip-shaped metal layers 3b and 3c are vertically stacked with an insulating layer 3a interposed therebetween. Is processed into an S-shape. Then, at the tip portion, the lower metal layer 3b has the same length as the insulating layer 3a,
The metal layer 3c is stretched so that it can be connected to the metal layer 7. Further, the two-layer laminated wiring pattern 4 is extended from the insulating layer 6 so as to be connected to the metal layer 3b.

The two-layer laminated wiring pattern 4 is used for a differential signal as described above when handling a signal, and is used for supplying a positive or negative voltage when used as a power supply line. In the case of the power line, different voltages (for example, 5V and 1
2V) may be supplied to the metal layer 5 and the metal layer 7. If matching of transmission impedance is required, it is necessary to examine the thickness and width of the two-layer laminated wiring pattern 4.

As described above, since the wiring on the multilayer printed board 1 is the two-layer laminated wiring pattern 4, it is not necessary to arrange the two wirings side by side for the differential signal line, which is the same as the single end. Transmission with a differential signal becomes possible at a mounting density.

FIG. 2 is a perspective view showing a wiring structure at an end portion for making an external connection or a semiconductor device having a pin having a normal shape.

When connecting to an external circuit via a connector or the like (or connecting a package pin to a semiconductor device not having a multi-layer structure), the wiring of the terminal portion cannot have a two-layer shape. Therefore, only the ends are formed into parallel wirings by the metal wirings 8a and 8b of one layer, and the metal wiring 5 is connected to the two-layer laminated wiring pattern 4 for the metal wiring 8a.

To the metal wiring 8b, the space between the metal wirings 8a and 8b is filled with an insulating layer 9, and a conductor 10 is provided so as to cover the upper surface and the rear end of the metal wiring 8b for connection. The conductor 10 can be formed by using, for example, a plating technique.

By performing connection conversion (layer conversion) between the two-layer laminated wiring pattern 4 and the parallel wiring formed by the metal wirings 8a and 8b in this manner, connection with an external circuit (external substrate) can be easily performed. In addition, there is an advantage that the conventional through-hole technology can be used. Also, in the connector portion of the electronic circuit package, if this one-layer pattern is used,
Connection can be facilitated.

[0020]

Second Embodiment FIG. 3 is a sectional view showing another embodiment of the wiring board of the present invention.

This embodiment is characterized in that a through hole is used and the through hole portion has the same function as the coaxial cable. The multilayer substrate 11 is provided with an inner layer pattern 12 at an intermediate portion, a two-layer laminated wiring pattern 13 having the same structure as the two-layer laminated wiring pattern 4 of the above-described embodiment is formed on the front surface, and a two-layer laminated wiring pattern having the same structure is formed on the back surface. A laminated wiring pattern 14 is formed.

At least one through hole 15 is formed in the thickness direction of the multi-layer substrate 11, and a through hole plating layer 16 is provided on the inner peripheral surface thereof. The embedded conductor 17 is inserted through the center of the through hole 15. The insulating material 18 is filled in the through hole 15 so as to fix the embedded conductor 17 and surround the embedded conductor 17.

This insulating material 18 is provided to electrically insulate the through-hole plating layer 16, and its exposed surface with respect to the two-layer laminated wiring pattern 13 and the two-layer laminated wiring pattern 14. , Are formed to be on the same plane. Furthermore, in order to connect the embedded conductor 17 to the two-layer laminated wiring pattern 13 and the two-layer laminated wiring pattern 14, the embedded conductor 17 and the two-layer laminated wiring patterns 13 and 2 are connected.
Connection metal layers 19a and 19b are provided so as to cover a part of the layer laminated wiring pattern 14.

As described above, since the through hole 15 has the same structure as that of the coaxial cable, the noise resistance is improved and the S / N can be prevented from lowering.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, although the semiconductor device is of the QFP type in the above embodiment, the present invention is not limited to this. Further, although the two-layer type package pin is used in the above-mentioned embodiment, the conventional one may be a pin having a structure of one conductor. In this case, it may be connected to the metal wirings 8a and 8b which are wired in parallel as shown in FIG.

Further, in the above embodiment, the metal laminated wiring pattern and the package pin have two layers. However, the present invention is not limited to this, and may have three or more layers.

In the above embodiment, the electronic component mounted on the substrate is a semiconductor device such as an LSI, but the invention is not limited to this, and circuit elements such as an inductance (or a coil), a capacitor and a resistor. It may be an electronic component in which an active element such as a transistor and a transistor is combined. Further, it may be an electronic component that does not include an active element.

[0029]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

In other words, the wiring board is such that an electronic component such as an IC is mounted and a wiring pattern connected to a pin of the electronic component is formed on at least one surface, and the wiring pattern is mutually insulated in the thickness direction. Since it is formed in at least two layers, it is possible to perform high-speed transmission while eliminating the influence of noise without lowering the packaging density.

[Brief description of drawings]

FIG. 1 is a side view showing a wiring board according to the present invention.

FIG. 2 is a perspective view showing an end wiring structure for connection to the outside or a semiconductor device having a pin having a normal shape.

FIG. 3 is a cross-sectional view showing another embodiment of the wiring board of the present invention.

[Explanation of symbols]

 1 Multilayer Printed Circuit Board 2 LSI 3 Package Pin 3a Insulating Layer 3b, 3c Metal Layer 4 2 Layer Laminated Wiring Pattern 5 Metal Layer 6 Insulating Layer 7 Metal Layer 8a, 8b Metal Wiring 9 Insulating Layer 10 Conductor 11 Multilayer Substrate 12 Inner Layer Pattern 13 2 Layer laminated wiring pattern 14 Two layer laminated wiring pattern 15 Through hole 16 Through hole plated layer 17 Embedded conductor 18 Insulating material 19a, 19b Metal layer for connection

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H05K 3/46 Q 6921-4E

Claims (4)

[Claims] 1. A wiring board on which an electronic component such as an IC is mounted and a wiring pattern connected to a pin of the electronic component is formed on at least one surface, and the wiring pattern is insulated from each other in a thickness direction. A wiring board characterized by being formed into at least two layers. 2. When connecting the multilayer wiring pattern formed in at least two layers and the one-layer wiring pattern wired in parallel, the wiring layers above the multilayer wiring pattern are connected in a direction perpendicular to each other. The wiring board according to claim 1, wherein the wiring board is formed through a connecting member having a plurality of insulating layers and conductor layers. 3. The multi-layer wiring pattern formed in at least two layers is formed on both surfaces of a substrate, and the multi-layer wiring patterns on the upper and lower surfaces are connected via through holes having a coaxial structure. 1. The wiring board according to 1. 4. At least one electronic component is mounted on a substrate having a multilayer wiring pattern formed in at least two layers, and at least one of signal pins or power supply pins of the electronic component is connected to the multilayer wiring pattern. An electronic circuit device characterized by the above.