JP2003163466A - Multilayer printed circuit board and multilayer printed circuit board device provided with the printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer printed circuit board capable of improving a radiation noise reducing effect and a multilayer printed circuit board device provided with the printed circuit board. <P>SOLUTION: The multilayer printed circuit board has a ground layer, a power supply layer 13 and an insulating layer formed between the ground layer and the layer 13. The layer 13 consists of three divided power supply layers 30A, 30B, 30C. The shapes of these layers 30A, 30B, 30C respectively depend on the leading time of integrated circuit elements to be respectively connected to the layers 30A, 30B, 30C. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed circuit board on which integrated circuit elements such as IC (integrated circuit) and LSI (large scale integrated circuit) are mounted, and a multilayer printed circuit provided with this multilayer printed circuit board. The present invention relates to a substrate device.

[0002]

2. Description of the Related Art Conventionally, as a multilayer printed circuit board, there is a multilayer printed circuit board provided with a power source layer, a ground layer, and an insulating layer provided therebetween. In such a multilayer printed circuit board, since the power supply layer and the ground layer behave as parallel plates, there is a problem that radiation noise increases near the resonance frequency.

A multilayer printed circuit board for solving the above problem is disclosed in Japanese Patent Laid-Open No. 11-340629.

The multilayer printed circuit board disclosed in JP-A-11-340629 is a printed circuit board having a structure in which a signal line is sandwiched between a ground conductor layer and a power conductor layer, and the power conductor layer is divided and divided. Inductance elements connect the power supply conductor layers. As a result, in the parallel plate formed by the conductor layer for ground and the conductor layer for power supply, the resonance frequency changes depending on the mode fed by the signal line, or between the conductor layer for ground and the conductor layer for power supply. Radiated noise is reduced as the induced electromagnetic field is attenuated.

[0005]

By the way, Japanese Unexamined Patent Application Publication No. H11-11
According to the multilayer printed circuit board of JP-A-340629, the division of the power conductor layer depends on the routing of the signal line of the signal layer sandwiched between the ground conductor layer and the power conductor layer. In this case, when the integrated circuit element is mounted on the multilayer printed circuit board and the integrated circuit element is switched, a through current flows from the power supply terminal of the integrated circuit element to the ground terminal of the integrated circuit element through the multilayer printed circuit board. Flowing. Since such a shoot-through current excites the ground conductor layer and the power conductor layer as parallel flat plates, there is a problem that radiation noise increases. That is, the above-mentioned multilayer printed circuit board has a problem that the effect of reducing radiation noise is low.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a multilayer printed circuit board and a multilayer printed circuit board device having the same, which can enhance the effect of reducing radiation noise.

[0007]

To achieve the above object, a multilayer printed circuit board according to the present invention comprises a power supply layer, a ground layer, and an insulating layer provided between the power supply layer and the ground layer. In the multilayer printed circuit board having an integrated circuit element mounted on at least one of the front and back surfaces, the power supply layer is composed of a plurality of divided power supply layers, and the shape of the divided power supply layer is each of the divided power supply layers. It is characterized in that it has a shape depending on the rise time of the integrated circuit element to be connected to.

According to the multilayer printed circuit board having the above structure, the power supply layer is composed of a plurality of divided power supply layers, so that the resonance frequency between the power supply layer and the ground layer is shifted to a high frequency band. At this time, since the shape of the divided power supply layer depends on the rise time of the integrated circuit element to be connected to each of the divided power supply layers, the voltage between the power supply layer and the ground layer is higher than the cutoff frequency. The resonance frequency of is shifted. As a result, unnecessary radiation noise is reduced, and the radiation noise reduction effect can be enhanced.

In the multilayer printed circuit board according to one embodiment, the plurality of divided power supply layers are connected to each other by conductors.

According to the multilayer printed circuit board of the above embodiment, since the plurality of divided power supply layers are connected to each other by the conductors, it is only necessary to connect one of the plurality of divided power supply layers to, for example, the power supply device. Power can be supplied to all of the plurality of divided power supply layers.

In the multilayer printed circuit board according to one embodiment, the divided power supply layer has a rectangular shape, and the long side length L1 of the divided power supply layer is expressed by the following equation (1). ε _r : Relative permittivity of the insulating layer T _r : Satisfies the signal rise time of the integrated circuit element.

According to the multilayer printed circuit board of the above-described embodiment, the divided power supply layer has a rectangular shape, and the length L1 of the long side of the divided power supply layer satisfies the expression (1). The reduction effect can be surely enhanced.

In the multilayer printed circuit board according to one embodiment, the divided power supply layer has a polygonal shape, and the outer peripheral length L2 of the divided power supply layer is expressed by the following equation (2). ε _r : Relative permittivity of the insulating layer T _r : Satisfies the signal rise time of the integrated circuit element.

According to the multilayer printed circuit board of the above-described embodiment, the divided power supply layer has a polygonal shape, and the outer peripheral length L2 of the divided power supply layer satisfies the expression (2). The effect can be surely enhanced.

Further, the multilayer printed circuit board device of the present invention is characterized by including the multilayer printed circuit board and the integrated circuit element mounted on at least one of the front and back surfaces of the multilayer printed circuit board. .

According to the multilayer printed circuit board device having the above structure, since the multilayer printed circuit board is provided, the resonance frequency between the power supply layer and the ground layer shifts above the cutoff frequency. As a result, unnecessary radiation noise is reduced, and the radiation noise reduction effect can be enhanced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multilayer printed circuit board of the present invention and a multilayer printed circuit board device having the same will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a schematic sectional view of a multilayer printed circuit board device according to an embodiment of the present invention, and FIG. 2 is a schematic plan view of the multilayer printed circuit board device as seen from above.

The above-mentioned multilayer printed circuit board device is shown in FIG.
As shown in FIG. 2, the multilayer printed circuit board 10 and the surface of the multilayer printed circuit board 10 (the upper surface in FIG. 1)
And a plurality of integrated circuit elements 20 mounted on.

The multilayer printed circuit board 10 has a signal layer 11 and a ground layer 1 in order from the front side (upper side in FIG. 1).
2, a power supply layer 13 and a signal layer 14 are provided. An insulating layer 15 is provided between these layers.

The integrated circuit element 20 is connected to the signal layer 11 and has a ground terminal 22 and a power supply terminal 23 in the same package. The ground terminal 22 is connected to the ground layer 12 via a through hole 24, and the power supply terminal 23 is connected to the power supply layer 13 via a through hole 25.

The power supply layer 13 is composed of three divided power supply layers 30A, 30B and 30C as shown in FIG. The X mark in FIG. 3 indicates a portion to which the through hole 25 is connected.

Next, the relationship between the shape of the divided power supply layer and the radiation noise will be described.

During the switching operation of the integrated circuit element 20, a through current flows from the power supply terminal 23 to the ground terminal 22 via the multilayer printed circuit board 10. This through current excites the ground layer 12 and the power supply layer 13 as a parallel plate, and the radiation noise increases. Especially in the vicinity of the resonance frequency, the radiation noise becomes high. The resonance frequency is the power supply layer 13
It depends on the planar shape of the ground layer 12 and the ground layer 12, and the resonance frequency can be shifted to a high frequency band by configuring the power layer with a plurality of divided power layers.

Assuming that the rise time of the clock of the integrated circuit device 20 is _Tr , the frequency characteristic of the high frequency component of the through current is such that the high frequency component is sufficiently attenuated at the point that the attenuation rate changes from -20 dB to -40 dB. ing. The cutoff frequency f at the change point has a value represented by the following equation (3).

When the dielectric constant of the insulating layer 15 of the multilayer printed circuit board 10 is ε _r , the cutoff frequency f
The wavelength λ at is a value represented by the following equation (4).

When the split power supply layer has a rectangular shape, resonance at the lowest frequency occurs at a frequency where the long side length L1 of the split power supply layer is equal to a half wavelength. Therefore, if the long side length L1 of the divided power supply layer satisfies the following expression (5), the power supply layer 1
The high frequency component of the through current at the resonance frequency between the antenna 3 and the ground layer 12 is sufficiently attenuated, and the radiation noise can be reduced.

When the divided power supply layer has a polygonal shape, if the outer peripheral length L2 of the power supply layer satisfies the following expression (6), the penetration at the resonance frequency between the power supply layer and the ground layer 12 is performed. The high frequency component of the current is sufficiently attenuated, and the radiation noise can be reduced.

Further, the power supply terminal 2 of the integrated circuit element 20.
When the divided power supply layers 30A, 30B, 30C connected to 3 do not satisfy the above formula (5) or formula (6),
Divide the power division layer. By performing this division for all of the plurality of divided power supply layers, the power supply layer and the ground layer 12
The resonance frequency between and can be moved to a frequency where the high frequency component of the through current is sufficiently attenuated, and the radiation noise can be reduced.

If the printed circuit board having the ground layer and the power supply layer has the above-described effect of reducing the radiation noise, the effect of reducing the radiation noise is 4
It can also be obtained in printed circuit boards with more layers than layers.

Next, the effect of reducing radiation noise was confirmed by simulation analysis. This simulation analysis employs an equivalent circuit model in which the power supply / ground layer of the multilayer printed circuit board 10 is represented by a lumped constant circuit of a capacitance C, an inductance L and a resistance R. FIG. 4 shows the equivalent circuit model. Here, both the power supply layer and the ground layer were divided into square areas, and the C, L, and R values of each area were calculated by the following formula.

Here, ε, μ, 1, d, ρ, and t are the permittivity of the insulating layer between the power / ground layers, the magnetic permeability of the insulating layer between the power / ground layers, the length of one side of the divided region, and the power source, respectively. / Thickness of insulating layer between ground layers, resistivity of power supply / ground conductor, thickness of power supply / ground conductor.

The upper limit of the simulation analysis frequency is set to 1 GHz, and 1/10 of the simulation analysis wavelength is set.
The substrate was divided by l = 10 mm to form the equivalent circuit as follows.

Substrate by SPICE simulation
S-parameter reflection characteristics S at the upper observation point₁₁Calculate
I put it out. This reflection characteristic S₁₁Is the wave incident on the observation point
The ratio of reflected waves is shown. Also, the power layer and
When resonance occurs with the land layer, the impeder at the observation point
Since the impedance becomes low and a part of the incident wave is radiated, S
₁₁Becomes smaller.

Then, for example, the rising time T _r of the clock signal is 800 ps and the relative permittivity ε _r of the insulating layer is 4.
6 In this case, the cutoff frequency f is about 400M
Hz and the wavelength λ is about 350 mm. As described above, when the wavelength λ of the cutoff frequency f is about 350 mm, the rectangular power supply layer 113 shown in FIG. 5 has a long side length of 240 mm, which does not satisfy the formula (5).

FIG. 7 shows the simulation analysis value of S ₁₁ with the X mark (the place where the through hole is connected) in FIG. 5 as the observation point. As can be seen from FIG. 7, the lowest resonance frequency (hereinafter referred to as “first resonance frequency”)
Is about 295 MHz. At this time, no matter which X mark in FIG. 5 is selected as an observation point, the first resonance frequency becomes the same value of about 295 MHz. In this case, the first resonance frequency (29
5 MHz) is a frequency lower than the cut-off frequency f (400 MHz), the high frequency component of the through current is not sufficiently attenuated, and the radiation noise increases near the first resonance frequency.

In the power supply layer 113 shown in FIG. 5, the above equation (5) is used.
Is not satisfied, the rectangular power supply layer 113 is divided into
As shown in FIG. 6, two rectangular divided power supply layers 130 are provided.
A and 130B are formed. This rectangular divided power supply layer 13
0A and the long side of the divided power supply layer 130B have a length of 150 m.
Since m, the above formula (5) is satisfied.

FIG. 8 shows S _{11 of the} divided power supply layer 130A.
The simulation analysis value of is shown. As can be seen from FIG. 8, the power supply layer 113 is divided into the divided power supply layers 13
By forming 0A and 130B, the first resonance frequency is moved from 295 MHz to 470 MHz. The first resonance frequency (470 MHz) shown in FIG. 8 is higher than the cutoff frequency f (400 MHz). Further, since the divided power supply layers 130A and 130B have the same shape, the resonance frequency has the same value. Therefore, the first resonance frequency (470 MHz) in the divided power supply layers 130A and 130B is the cutoff frequency f (40
0 MHz), the high frequency component of the through current is sufficiently attenuated, and the radiation noise can be reduced.

Further, when the wavelength λ of the cutoff frequency f is about 350 mm, the outer peripheral length of the polygonal power supply layer 213 shown in FIG. 9 is 560 mm, and therefore the above expression (6) is not satisfied.

FIG. 11 shows the simulation analysis value of S _{1 1} with the X mark (the place where the through hole is connected) in FIG. 9 as the observation point. From FIG. 11, the first resonance frequency is about 36.
It can be confirmed that the frequency is 5 MHz. In this case, the first resonance frequency (365 MHz) is equal to the cutoff frequency f (400
MHz), the high frequency component of the through current is not sufficiently attenuated, and the radiation noise increases near the first resonance frequency.

Since the power supply layer 213 shown in FIG. 9 does not satisfy the above equation (6), the polygonal power supply layer 213 is divided into
As shown in FIG. 10, a rectangular divided power supply layer 230A and a polygonal divided power supply layer 230B are formed. as a result,
The long side of the rectangular divided power supply layer 230A has a length of 100.
mm, which satisfies the above formula (5). Further, the polygonal divided power supply layer 230B has an outer circumference of 320 mm, which satisfies the above expression (6).

FIG. 12 shows S _{11 of the} divided power supply layer 230A.
And the simulation analysis value of S ₁₁ of the divided power supply layer 230B is shown in FIG.

In FIG. 12, the first resonance frequency is about 690 MH.
It can be confirmed that the first resonance frequency is about 625 MHz in FIG. In this way, the polygonal power supply layer 213 is divided, and as shown in FIG. 10, the rectangular power supply layer 230A and the polygonal power supply layer 230B are divided.
By forming and, the first resonance frequency becomes higher than the cutoff frequency f (400 MHz). As a result, the high frequency component of the through current is sufficiently attenuated, and the radiation noise can be reduced.

In the above embodiment, the integrated circuit element 20 is provided on the surface (upper surface in FIG. 1) of the multilayer printed circuit board 10.
Although the integrated circuit element 20 may be mounted on the back surface (lower surface in FIG. 1) of the multilayer printed circuit board 10, or on both the front and back surfaces of the multilayer printed circuit board 10. Integrated circuit elements may be implemented. In short, the integrated circuit element may be mounted on at least one of the front and back surfaces of the multilayer printed circuit board 10.

The integrated circuit device may be an IC or LSI, for example, and may be a crystal clock oscillator or the like.

In the above embodiment, the divided power supply layer 3 is used.
Although 0A, 30B and 30C are not connected to each other, the divided power supply layers 30A, 30B and 30C may be connected to each other by a conductor. In this case, the divided power supply layers 30A, 3
Power can be supplied to all of the divided power supply layers 30A, 30B, and 30C by simply connecting one of the 0B and 30C to a power supply device, for example.

[0047]

As is apparent from the above, in the multilayer printed circuit board according to the present invention, the shape of the plurality of divided power supply layers constituting the power supply layer is such that the integrated circuit element to be connected to each of the divided power supply layers rises. Since the shape depends on time, the resonance frequency between the power supply layer and the ground layer shifts to the cutoff frequency or higher, and the effect of reducing radiation noise can be enhanced.

In the multilayer printed circuit board according to one embodiment, since the plurality of divided power supply layers are connected to each other by conductors, a plurality of divided power supply layers can be connected to, for example, a power supply device. Power can be supplied to all of the divided power supply layers.

In the multilayer printed circuit board according to one embodiment, when the divided power supply layer has a rectangular shape, the long side length L1 of the divided power supply layer is expressed by the following equation (1). ε _r : Relative permittivity T _r of the insulating layer: Since the rise time of the signal of the integrated circuit element is satisfied, the effect of reducing radiation noise can be surely enhanced.

In the multilayer printed circuit board according to one embodiment, when the divided power supply layer has a polygonal shape, the outer peripheral length L2 of the divided power supply layer is expressed by the following equation (2). ε _r : Relative permittivity T _r of the insulating layer: Since the rise time of the signal of the integrated circuit element is satisfied, the effect of reducing radiation noise can be surely enhanced.

Further, since the multilayer printed circuit board device of the present invention is provided with the above-mentioned multilayer printed circuit board, the resonance frequency between the power supply layer and the ground layer shifts to the cutoff frequency or higher, and the radiation noise is reduced. The reduction effect can be enhanced.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a multilayer printed circuit board device according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of the multilayer printed circuit board device of FIG.

FIG. 3 is a schematic plan view of a power supply layer of the multilayer printed circuit board according to the embodiment of the present invention.

FIG. 4 is a diagram showing an equivalent circuit model of a power supply / ground layer.

FIG. 5 is a schematic plan view of an example of a rectangular power supply layer.

FIG. 6 is a schematic plan view showing an example of the power supply layer of FIG. 5 after division.

7 is a diagram showing a graph of a simulation analysis result of S ₁₁ of the power supply layer of FIG.

8 is a diagram showing a graph of a simulation analysis result of S ₁₁ of the divided power supply layer of FIG.

FIG. 9 is a schematic plan view of an example of a polygonal power supply layer.

FIG. 10 is a schematic plan view showing an example of the power supply layer of FIG. 9 after division.

11 is a diagram showing a graph of S ₁₁ simulation analysis results of the power supply layer of FIG. 9;

12 is a diagram showing a graph of a simulation analysis result of S ₁₁ of one of the divided power supply layers in FIG.

13 is a diagram showing a graph of a simulation analysis result of S ₁₁ of the other divided power supply layer in FIG.

[Explanation of symbols]

10 Multilayer printed circuit board 12 ground layer 13 Power layer 15 Insulation layer 20 integrated circuit elements 30A, 30B, 30C split power supply layer

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Claims (5)

[Claims] 1. A multilayer printed circuit board comprising a power supply layer, a ground layer, and an insulating layer provided between the power supply layer and the ground layer, and an integrated circuit element being mounted on at least one of the front and back surfaces. In the above, the power supply layer is composed of a plurality of divided power supply layers, and the shape of the divided power supply layer is a shape depending on the rise time of the integrated circuit element to be connected to each of the divided power supply layers. A multilayer printed circuit board characterized by the above. 2. The multilayer printed circuit board according to claim 1, wherein the plurality of divided power supply layers are connected to each other by conductors. 3. The multilayer printed circuit board according to claim 1, wherein the divided power supply layer has a rectangular shape, and the long side length L1 of the divided power supply layer is expressed by the following equation (1). ε _r : relative permittivity T _r of the insulating layer: a multilayer printed circuit board characterized by satisfying the signal rise time of the integrated circuit element. 4. The multilayer printed circuit board according to claim 1, wherein the divided power supply layer has a polygonal shape, and the outer peripheral length L2 of the divided power supply layer is expressed by the following equation (2). ε _r : relative permittivity T _r of the insulating layer: a multilayer printed circuit board characterized by satisfying the signal rise time of the integrated circuit element. 5. A multilayer printed circuit board according to any one of claims 1 to 4, and the integrated circuit device mounted on at least one of the front and back surfaces of the multilayer printed circuit board. Multilayer printed circuit board device.