JP2000340956A - Multilayered wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mutilayered wiring board, having a high degree of freedom in wiring and a simplified manufacturing process by providing a via hole within an inner layer of the board with electric resistance. SOLUTION: A wiring pattern 4 is electrically connected to a wiring pattern 5, through a via hole 2 having electric resistance which is formed by filling a hole formed in an inner layer of a board 1 with a conductive paste and a resistor paste. Since the hole 2 has electric resistance, it is no longer necessary to use a separate chip resistor or the like for resistance connection between the patterns 4 and 5, which then requires an area not larger than that of the hole 2 for the resistance connection between the patterns 4 and 5. This not only increases the degree of flexibility in wiring, but also simplifies the manufacturing process. Further, even a multilayered wiring board, having an insulation layer whose thickness is 100 μm or less, can be formed into a resistor- incorporated multilayered wiring board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board on which various electronic components can be mounted and electrically connected to each other to form an electronic circuit. Regarding the connection structure.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller and denser,
There is a strong demand that multilayer wiring boards be supplied at low cost in the field of consumer equipment as well as in industrial applications. In such a multilayer wiring board, it is important that a plurality of wiring patterns formed at a fine wiring pitch and a myriad of electronic components mounted on the surface of the board can be electrically connected with high connection reliability.

FIG. 6 is a sectional view showing an example of a conventional multilayer wiring board. On the surface and the inner layer of the base material 1, wiring patterns 4 and 5 of a metal conductor are arranged, respectively.
Lands 6 and 7 are formed at ends of the wiring patterns 4 and 5 for electrical connection. Via holes 2 are formed in the substrate 1, and the wiring patterns 5 and the chip resistors 8 on the substrate 1 are electrically connected through the via holes 2. Further, the chip resistor 8 and the wiring pattern 4 are electrically connected via the land 6.

In the multilayer wiring board having such a configuration, the mounting of electronic components on a limited surface of the substrate and the electrical connection wiring between these electronic components and the wiring pattern of the inner layer of the substrate are beginning to have a limit. Efforts are being made to minimize the size of components and to incorporate the board.

[0005] Many studies have been made on the incorporation of electronic components into a substrate, especially for resistors that are frequently used. For example, a method of inserting a chip component into a via hole, a method of filling a resistor paste into a via hole (hereinafter, referred to as a “through hole”) penetrating all layers of a substrate, and a method of forming a wiring pattern of a specific layer centering on a surface layer A method has been proposed in which a part is formed of a resistor by printing or the like.

[0006]

However, the minimization of the electronic components and the incorporation of the substrate into the substrate have the following problems. Minimization of electronic components can increase the number of components mounted on the board surface, but the electrical connection wiring between the electronic components on the surface of the board and the wiring patterns on the inner layer of the board also increases and becomes complicated, and in the worst case, There was a problem that wiring became impossible.

Further, in the conventional method of incorporating electronic components into a substrate, there are cases where chip components are too large to be inserted into a multilayer substrate having an insulating layer thickness of 100 μm or less. This reduces the degree of freedom in wiring. Further, in the case of forming a resistor by printing at the time of pattern formation, there is a problem that the cost increases due to an extra manufacturing process.

The present invention solves the above-mentioned conventional problems. Since the via holes in the inner layer of the substrate have an electric resistance value, the degree of freedom of wiring is high, the manufacturing process is simple, and the insulating layer is formed. It is an object of the present invention to provide a multilayer wiring board that can be of a built-in resistor type even if the multilayer wiring board has a thickness of 100 μm or less.

[0009]

In order to achieve the above object, a multi-layer wiring board according to the present invention comprises a via hole having an electric resistance formed in an inner layer of a substrate, at least one of which is formed in the inner layer of the substrate. The two different wiring layers are electrically connected. According to the multilayer wiring board as described above, since the via hole in the inner layer of the board has an electric resistance value, it is not necessary to separately use a chip resistor or the like for the resistance connection between the wiring layers. For this reason, since the resistance connection between the wiring layers does not require an area larger than the via hole, the degree of freedom in wiring is increased and the manufacturing process is simplified. Furthermore, a multilayer wiring board with a built-in resistor can be used even with a multilayer wiring board having an insulating layer thickness of 100 μm or less.

In the multilayer wiring board, it is preferable that the via hole is formed by filling a hole formed in an inner layer of the board with a conductive paste and a resistor paste. According to the multilayer wiring board as described above, the electric resistance value of the via hole can be controlled by changing the electrical and physical characteristics of the conductive paste and the resistor paste.

It is also possible to have a plurality of via holes having different electric resistance values formed by changing the diameter of the via holes. According to the multilayer wiring board as described above, it is possible to control the electric resistance value of a wide range of via holes.

Further, the electrical connection between the two different wiring layers may be made through a plurality of via holes. According to the multilayer wiring board as described above,
It is possible to control the electric resistance value of a wide range of via holes.

In addition, the wiring pattern is terminated or connected in series or in parallel to a ground layer or a power supply layer in the substrate via the via hole, and is electrically connected to the wiring pattern for transmitting and receiving a high-frequency signal to and from the wiring pattern. It is also possible to match the characteristic impedance of the obtained semiconductor with the electric resistance of the via hole.

According to the multilayer wiring board as described above, since the portion corresponding to the terminating resistor is built in as a via hole, it is possible to cope with high frequency signal transmission without using a terminating resistor separately, The degree of freedom in component arrangement and wiring can be improved.

Further, the multilayer wiring board may be a carrier board for connecting a semiconductor chip and a printed wiring board. According to the multilayer wiring board as described above, the portion corresponding to the terminating resistor is built in as a via hole of the carrier substrate, so that the terminating resistor is used separately from the surface of the printed wiring board on which the carrier substrate is mounted without using a terminating resistor. The degree of freedom in component arrangement and multilayer wiring can be increased.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a multilayer wiring board according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1A is a sectional view showing a connection structure of a via hole portion of a multilayer wiring board according to Embodiment 1 of the present invention. A wiring pattern 4 of a metal conductor is arranged on the surface of the substrate 1, and a wiring pattern 5 of the metal conductor is also arranged on the inner layer. Lands 6 and 7 are formed at ends of the wiring patterns 4 and 5, respectively, for making electrical connection between the wiring patterns 4 and 5.

Further, a via hole 2 is formed in the substrate 1 by filling a resistor 3 into a hole formed by a drill, a laser or the like. The resistor 3 is formed by filling a conductive paste and a resistor paste in the hole, and the resistor 3 and the lands 6 and 7 are electrically connected by press pressure or the like.

FIG. 1B is a circuit diagram showing an electrical function of the multilayer wiring board according to the present embodiment. In this embodiment, a portion corresponding to the resistor 3 is built in the substrate 1. . For the resistor 3, a conductive paste and a resistor paste having electric and physical characteristics such that the electric resistance between the land 6 and the land 7 is in a specific range (for example, 50 ± 5Ω) are selected. . That is, by changing the electrical and physical properties of the conductive paste and the resistor paste,
The electric resistance value of the via hole can be controlled.

For this reason, in the present embodiment, an electrical function equivalent to that of the conventional structure as shown in FIG. 6 is realized without using the chip resistor 8. According to the present embodiment,
Since the resistance connection between the wiring layers does not require an area larger than the via hole, the degree of freedom in wiring is increased and the manufacturing process is simplified. Furthermore, a multilayer wiring board with a built-in resistor can be used even with a multilayer wiring board having an insulating layer thickness of 100 μm or less.

(Embodiment 2) FIG. 2 is a sectional view showing a connection structure of a via hole portion of a multilayer wiring board according to Embodiment 2 of the present invention. In the present embodiment, in the multilayer wiring board of the first embodiment, the hole diameter of the via hole 2 is changed,
This is an embodiment in which the resistance value of the via hole 2 is changed.

That is, if the hole diameter 10 of the via hole 2 is doubled with the same material, the electric resistance value of the via hole 2 can be reduced to ４. By changing the hole diameter of the plurality of via holes 2, the electric resistance value of each via hole 2 can also be changed.

(Embodiment 3) FIG. 3 is a sectional view showing a connection structure of a via hole portion of a multilayer wiring board according to Embodiment 3 of the present invention. The third embodiment is an embodiment in which the resistance value of the via hole 2 is changed by increasing the number of via holes 2 in the multilayer wiring board of the first or second embodiment. That is, the via hole 2 is made of the same material.
By doubling the number of holes, the electric resistance value of the via hole 2 can be reduced to half.

(Embodiment 4) FIG. 4 is a sectional view showing a connection structure of a via hole portion of a multilayer wiring board according to Embodiment 4 of the present invention. In this embodiment, the wiring pattern 4 is terminated via the via hole 2 in parallel with the ground layer 11. The connection between the wiring pattern 4 and the via hole 2 is made via the land 6. The connection between the semiconductor 13 and the via hole 2 is made via the lands 6 and 7, and the terminal 14 of the semiconductor 13 is connected to the land 7 by the solder 9.
Soldered. The via hole 2 is filled with a resistor 3 having a resistance value of 50Ω, and the characteristic impedance of the wiring pattern 4 is 50Ω.

In this embodiment, since the via hole 2 has an electric resistance value, the semiconductor 1 for transmitting and receiving a high-frequency signal is used.
The characteristic impedance of the wiring pattern 4 and the characteristic impedance of the wiring pattern 4 can be matched by the electric resistance of the via hole 2 to support high-frequency signal transmission. That is, since the terminating resistor conventionally mounted on the substrate surface is incorporated between the wiring layers in the present embodiment, the degree of freedom in arranging components on the substrate surface and wiring can be improved.

Although an example in which the wiring pattern 4 is terminated and connected in parallel with the ground layer 11 through the via hole 2 has been described, the wiring pattern is connected to the power supply layer 12 in the inner layer of the substrate through the via hole 2. The terminals may be connected in parallel.
In any case, the wiring pattern may be terminated and connected in series to the ground layer or the power supply layer in the substrate.

(Embodiment 5) FIG. 5 is a cross-sectional view showing a connection structure of via holes in an embodiment using a multilayer wiring board according to Embodiment 5 of the present invention as a carrier substrate. In the fifth embodiment, the semiconductor chip 13 is formed by the multi-layer wiring board 17 in which the via hole 2 filled with the resistor 3 having a constant resistance value is built in the base material 1 similarly to the multi-layer wiring board shown in the first to third embodiments. And the printed wiring board 16 are BGA (ball
grid array) implementation.

That is, the multilayer wiring board 17 is used as a carrier board, the semiconductor chip 13 and the lands 6a of the multilayer wiring board 17 are connected via the solder balls 15, and the lands 6b of the multilayer wiring board 17 are printed. The lands 7 of the wiring board 16 are similarly connected via the solder balls 15.

According to the present embodiment, since the terminating resistor conventionally mounted on the surface of the printed wiring board 16 is incorporated between the wiring layers of the multilayer wiring board 17 in the present embodiment, the carrier substrate is mounted. It is possible to increase the degree of freedom in arranging components on the surface of the printed wiring board and in multilayer wiring.

[0030]

As described above, according to the present invention, since the via hole in the inner layer of the substrate has an electric resistance value, it is not necessary to use a separate chip resistor or the like for the resistance connection between the wiring layers.
For this reason, since the resistance connection between the wiring layers does not require an area larger than the via hole, the degree of freedom in wiring is increased and the manufacturing process is simplified. Furthermore, a multilayer wiring board with a built-in resistor can be used even with a multilayer wiring board having an insulating layer thickness of 100 μm or less.

[0031]

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a via hole connection structure of a multilayer substrate according to a first embodiment of the present invention. FIG. 1B is a diagram illustrating an electrical function of the multilayer substrate according to the first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a via hole connection structure of a multilayer substrate according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a via hole connection structure of a multilayer substrate according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a high-frequency signal substrate according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a carrier substrate according to a fifth embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating an example of a conventional multilayer substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Via hole 3 Resistor 4, 5 Wiring pattern 6, 7 Land 8 Chip resistance 9 Solder 10 Hole diameter of via hole 11 Ground layer 12 Power supply layer 13 Semiconductor chip 14 Semiconductor terminal 15 Solder ball 16 Printed wiring board 17 Multilayer Wiring board

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (6)

[Claims] At least one of two different wiring layers formed in the substrate inner layer is electrically connected via a via hole having an electric resistance value formed in the substrate inner layer. Multilayer wiring board. 2. The multilayer wiring board according to claim 1, wherein the via hole is formed by filling a hole formed in the substrate inner layer with a conductive paste and a resistor paste. 3. The multilayer wiring board according to claim 1, further comprising a plurality of via holes having different electric resistance values formed by changing the diameter of the via holes. 4. The multilayer wiring board according to claim 1, wherein the two different wiring layers are electrically connected via a plurality of via holes. 5. A wiring pattern is terminated or connected in series or parallel to a ground layer or a power supply layer in an inner layer of a substrate via the via hole, and is electrically connected to the wiring pattern for transmitting and receiving a high-frequency signal to and from the wiring pattern. 5. The multilayer wiring board according to claim 1, wherein the characteristic impedance with the semiconductor is matched by the electric resistance value of the via hole. 6. The multi-layer wiring board is a carrier board for connecting a semiconductor chip and a printed wiring board.
5. The multilayer wiring board according to any one of items 1 to 4.