JPH1168322A - Multi-layer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-layer printed wiring board capable of raising density while reducing crosstalk noise and steepening the rise of the waveform of signals. SOLUTION: An inter-line insulation layer 36 for insulating a signal line 40S, a ground line 40G and a power supply line 40P is turned to a high dielectric constant and inter-layer insulation layers 30 and 130 for insulating layers are formed at a low dielectric constant. Since the coupling capacity of the signal lines 40S and 140S of upper and lower layers is lowered because the dielectric constant of the inter-layer insulation layer 30 is low, crosstalk between the signal lines of the upper and lower layers is reduced. Also, since the dielectric constant of the inter-line insulation layer 36 for insulating the signal line 40S, the ground line 40G and the power supply line 40P of the same conductor layer is high, it becomes similar to the case of equivalently bringing the signal line 40S and the ground line 40G and the power supply line 40P close and disposing them and the waveform of the signals (pulses) transmitted through the signal line is not made dull. That is, the leakage of an electric field becomes small and the rise of the waveform of the signals is quickened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power supply line and a ground line in a same conductor layer, or a power supply line or a ground line in a same conductor layer. The present invention relates to a multilayer printed wiring board in which upper and lower conductive circuits are insulated by an interlayer insulating agent.

[0002]

2. Description of the Related Art In a multilayer printed wiring board, it is necessary to reduce crosstalk noise between signal lines and to prevent the rise of signal waveform from becoming dull. Here, the crosstalk noise means that one signal line is affected by a signal on another signal line due to capacitive coupling with an adjacent signal line. The blunt rising of the signal waveform means that when a pulse P is transmitted on one signal line as shown in FIG. 7A and is affected by another signal line, the signal P shown in FIG. ) Means that the rise of the pulse P becomes dull. Here, if there is such a slowdown in the rising, when the pulse is transmitted at the time T1, the time T delayed by the time t on the receiving side is obtained.
2, the rising of the pulse P is detected, and a delay occurs in signal transmission. In order to minimize such transmission delay, it is necessary to make the waveform rise steeply.

As described above, in order to reduce the crosstalk noise between signal lines and to make the rising of the signal waveform sharp, a power supply film 40P is provided on the entire surface as shown in FIG. The power supply layer L1 is formed, the ground layer 340G is provided on the entire surface as the ground layer L4, and the signal lines 40S and 140S are provided in the layers L2 and L3 therebetween. However, in the configuration shown in FIG. 8A, since all of the layers are consumed in the power supply layer L1 and the ground layer L4, there is a certain limit in increasing the density. Therefore, as shown in FIG. 8B, in the same conductor layer L2, the signal line 140S is sandwiched between the ground line 140G and the power supply line 140P.
A configuration in which 0S is sandwiched between a ground line 40G and a power supply line 40P, or a configuration in which a signal line 40S is surrounded by a ground line 40G (or a power supply line) as shown in FIG.

[0004]

However, FIG.
In the configurations shown in FIGS. 8B and 8C, there were problems that the crosstalk noise was large and the rise of the signal waveform was slow. The present inventor has found that the cause of this problem is that the material between the signal line and the power supply line and between the signal line and the ground line and the material between the layers that insulate the signal lines are the same and have the same dielectric constant. It was found that there is.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to reduce crosstalk noise and increase the density of a signal while steeply rising a signal waveform. It is to provide a multilayer printed wiring board.

[0006]

According to a first aspect of the present invention, in order to achieve the above object, a signal line is sandwiched between a power supply line and a ground line in the same conductor layer, or a power supply line is provided in the same conductor layer. In a multilayer printed wiring board having at least two or more layers in which a signal line is surrounded by a line or a ground line, a technical feature is that a material for insulating between lines has a higher dielectric constant than a material for insulating between layers. I do.

According to a second aspect of the present invention, in the first aspect, a plurality of signal lines are surrounded by a power supply line and a ground line, or a plurality of signal lines are surrounded by the power supply line and the ground line in the same conductor layer.

[0008] In claim 3, in claim 1 or 2,
A technical feature is that the material for insulating between the lines and the material for insulating between the layers are obtained by adding inorganic particles to a resin.

According to the first aspect, since the dielectric constant of the material that insulates the layers is low, the coupling capacitance of the signal lines in the upper and lower layers is reduced, so that the crosstalk between the signal lines in the upper and lower layers is reduced. In addition, since the material that insulates between signal lines in the same conductor layer has a high dielectric constant, it is equivalent to being disposed close to a power supply line or a ground line equivalently adjacent to a signal line. The transmitted signal (pulse) is not blunted. That is, the leakage of the electric field is reduced, and the rise of the signal waveform is accelerated.

According to a second aspect of the present invention, a plurality of signal lines are sandwiched between a power supply line and a ground line, or a power supply line or a ground line, thereby increasing the ratio of signal lines in the wiring and increasing the density of the multilayer printed wiring board. Can be achieved.

According to the third aspect of the present invention, since the material for insulating between lines and the material for insulating between layers are formed by adding inorganic particles to a resin, the dielectric constant can be easily adjusted. Here, as the inorganic particles, alumina, titania, glass and the like are preferable.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multilayer printed wiring board according to a first embodiment of the present invention will be described below with reference to the drawings.
First, the configuration of the multilayer printed wiring board will be described with reference to FIG.
This will be described with reference to FIG. The printed wiring board of the first embodiment is configured such that the interlayer insulating layer 130 that insulates the first conductor layer L1 and the second relative layer L2 has a low dielectric constant. Also, the signal line 4 provided on the first conductor layer L1
0S is disposed between the ground line 40G and the power supply line 40P, and the signal line 40S, the ground line 40G, and the power supply line 40P.
The dielectric constant of the line insulating layer 36 that insulates P is configured to be higher than the dielectric constant of the interlayer insulating layer 30 described above.
Similarly, the signal line 140S, the ground line 140G, the power supply line 140P, and the line insulating layer 136 on the second conductor layer L2
Are formed.

Here, the signal line 40S on the first conductor layer L1
And the signal line 140S on the second conductor layer L2, the interlayer insulating layer 130 is configured to have a low dielectric constant, so that the capacitive coupling coefficient between the signal line 40S and the signal line 140S decreases, Crosstalk between both signal lines 40S and 140S is reduced.

The inter-layer insulating layer 36 between the signal line 40S and the power supply line 40P or the ground line 40G has a high dielectric constant, and is equivalently equivalent to the power supply line 40P adjacent to the signal line 40S.
Alternatively, it is equivalent to being disposed close to the ground line 40G, and the waveform of the signal (pulse) transmitted on the signal line 40S is not dulled. That is, the leakage of the electric field is reduced, and the rise of the signal waveform is accelerated.

FIG. 5A and FIG.
This will be described with reference to FIG. FIG. 5A shows the signal line 40.
The magnetic field line distribution when S and the ground line 40P are arranged apart from each other is indicated by a broken line, and the power line distribution is indicated by a solid line. FIG. 5B shows a distribution of magnetic force lines and a distribution of power lines when the signal line 40S and the ground line 40P are arranged close to each other. When the signal line 40S and the ground line 40P are arranged apart from each other as shown in FIG. 5A, the magnetic lines and the power lines from the signal line 40S of the first conductor layer L1 are connected to the second line.
Many intersect with the signal line 140S of the conductor layer L2. On the other hand, when the signal line 40S and the ground line 40P are disposed close to each other as shown in FIG. 5B, the magnetic lines and the power lines from the signal line 40S of the first conductor layer L1
It becomes difficult to cross the signal line 140S of the conductor layer L2. Here, increasing the dielectric constant of the line insulating layer 36 (see FIG. 4A) that insulates the signal line 40S from the ground line 40P is equivalent to increasing the dielectric constant as shown in FIG. 5B. This corresponds to disposing the line 40S and the ground line 40P close to each other,
The signal lines 140S of the second conductor layer L2 are less likely to be affected by the signal lines 40S of the first conductor layer L1. Therefore, FIG.
(A), the signal line 4 as described above with reference to FIG.
The waveform of the signal (pulse) transmitted through the 0S is not dulled, and the transmission speed of the pulse can be equivalently increased.

Subsequently, a method of manufacturing the low dielectric constant interlayer insulating material and the high dielectric constant line insulating material will be described. Here, first, the preparation of the interlayer insulating agent will be described. (A) Alicyclic epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc.
45 parts by weight of EPlCLONHP-7200) and a photosensitive monomer (trade name: Aronix M315, manufactured by Toagosei Co., Ltd.)
10 parts by weight, 0.5 of defoamer (S-NOPCO S-65)
Parts by weight and 3.6 parts by weight of NMP are stirred and mixed.

(B) Polyphenylene ether (PPE)
12 parts by weight, epoxy resin particles (trade name of Sanyo Chemical Industries, Ltd.)
After mixing 7.2 parts by weight of an average particle diameter of 1.0 μm and 3.09 parts by weight of an average particle diameter of 0.5 μm, further add 30 parts by weight of NMP, and stir and mix with a bead mill.

(C) imidazole curing agent (Shikoku Chemicals:
2E4MZ-CN (trade name), 2 parts by weight of photoinitiator (Irgacure 1-907, Ciba-Geigy), 0.2 part by weight of photosensitizer (DETX-S, manufactured by Nippon Kayaku), NM
Pl. Stir and mix 5 parts by weight. These (a),
(B) and (c) are mixed to obtain an interlayer insulating agent. The dielectric constant is about 3.3.

Next, the production of the line insulating agent will be described. (D) 20 parts by weight of bisphenol A type obtained by dissolving 100 parts by weight of a photosensitizing oligomer (molecular weight 4000) obtained by acrylate of 50% of an epoxy group of cresol nopolak type epoxy resin (manufactured by Nippon Kayaku) in methyl ethyl ketone Epoxy resin (Epicoat 100 made by Yuka Shell)
1) 32 parts by weight, 6.4 parts by weight of a polyacrylic monomer which is a photosensitive monomer (Nippon Kayaku R604), 3.2 parts by weight of a polyvalent acrylic monomer which is also a photosensitive monomer (DPE6A, manufactured by Kyoeisha Chemical) , And 0.5 part by weight of a leveling agent (Polyflow No. 75 manufactured by Kyoeisha Chemical Co., Ltd.) with respect to 100 parts by weight of the total weight, and then stirring and mixing.

(E) Imidazole curing agent (Shikoku Chemicals:
3.4 parts by weight of trade name 2E4MZ-CN), 2 parts by weight of a photoinitiator (Irgacure I-907 manufactured by Ciba Geigy),
0.2 parts by weight of a photosensitizer (DETX-S manufactured by Nippon Kayaku)
60 parts by weight of titania (average particle size 1.6 μm), NMP
Stir and mix 1.5 parts by weight. These (d) and (e) are mixed to obtain a line insulating agent. The dielectric constant is about 4.7.

Subsequently, regarding the process of manufacturing a multilayer printed wiring board using the above-described interlayer insulating agent and line-to-line insulating agent,
This will be described with reference to FIGS. (1) A starting material is a copper-clad laminate 20a in which 18 μm copper foils 22 are laminated on both sides of a substrate 20 made of glass epoxy resin or BT (bismaleimide triazine) resin having a thickness of 1 mm (FIG. 1 (A) )). First, this copper clad laminate 20a is drilled to form a through hole 24 for a through hole, and then a plating resist is formed.
Electroless plating is performed to form through-holes 26 (FIG. 1B). Further, copper foil 22 is etched in a pattern according to a conventional method to form inner layer copper patterns 28 on both surfaces of substrate 20 (FIG. 1B). 1 (C)).

(2) The resin insulating agent groups (a), (b) and (c) prepared as described above are stirred and mixed to prepare a resin insulating agent, and then the resin insulating agent is rolled on the surface of the substrate 20. It is applied uniformly by a coater and filled in the through holes 26. After standing for 20 minutes in a horizontal state,
Dried at 30 ° C. for 30 minutes to form an interlayer insulating layer 3 having a thickness of 35 μm.
0 (FIG. 1 (D))

(3) Substrate 20 on which interlayer insulating layer 30 is formed
A photomask film 32 on which a black circle 32a of 85 μmφ is printed is brought into close contact with both sides of
Exposure is performed at 00 mJ / cm ² (FIG. 1E). This is D
By performing spray development with an MTG solution, an opening serving as a via hole of 85 μmφ is formed in the interlayer insulating layer 30. Further, the substrate was 3,000 m long using an ultra-high pressure mercury lamp.
Exposure at J / cm ² , 1 hour at 100 ° C., then 150
By performing heat treatment at 5 ° C. for 5 hours, an opening (opening for forming a via hole) 30 a having excellent dimensional accuracy corresponding to a photomask film is formed. (FIG. 2 (F))

(4) The substrate 20 with the opening 30a formed
Is immersed in chromic acid for 2 minutes to dissolve the epoxy resin particles in the resin matrix to make the surface of the resin interlayer insulating layer 30 rough, and then immersed in a neutralizing solution (manufactured by Shipley Co.) and then washed with water. (FIG. 2 (G)).

(5) This roughening treatment (roughening depth 6 μm)
By applying a palladium catalyst (manufactured by Atotech) to the substrate subjected to the above, a catalyst nucleus is attached to the resin interlayer insulating layer 30 and the via hole opening 30a.

(6) The compositions (d) and (e) of the line insulating layer adjusted as described above are stirred and mixed to prepare a liquid resist. (7) On both surfaces of the substrate that has been subjected to the above-described process of providing catalyst nuclei,
The above liquid resist is applied using a roll coater, and 6
Dry lump for 30 minutes at 0 ° C, resist layer 3 of 30 μm thickness
2 (FIG. 2H).

(8) Next, the photomask film 34 on which the pattern 34a corresponding to the conductor circuit is formed is placed and irradiated with ultraviolet rays of 400 mJ / cm ² (FIG. 2 (I)).

(9) The photomask film 34 is removed, the resist layer is dissolved and developed with DMTG to form a plating resist on the substrate 20 from which the conductor circuit pattern has been removed, and furthermore, 6000 mJ / cm using an ultra-high pressure mercury lamp. Exposure is performed at ² ° C., and heat treatment is performed at 1000 ° C. for 1 hour and then at 150 ° C. for 3 hours to form a permanent resist 36 to be a line insulating layer on the interlayer insulating layer 30 (FIG. 3 (J)) .

(10) The substrate 20 on which the permanent resist 36 has been formed is subjected to a pre-plating treatment (specifically, activation of a catalyst nucleus), and then the resist is formed by electroless plating in an electroless copper plating bath. An electroless copper plating 38 having a thickness of about 15 μm is deposited on the non-formed portion to form an outer layer copper pattern (a ground line 40G and a power line 40 shown in FIG. 4A).
P, the signal line 40S) 40 and the via hole 42 are formed to form the first conductor layer L1 by the additive method. Metal salt: CuSO4 .5H2 O: 8.6 mM Complexing agent: TEA (triethanolamine): 0.15 M Reducing agent: HCHO: 0.02 M Other: Stabilizer (bipyridyl, potassium ferrocyanide, etc.): small amount 6 μm / hour

(11) After the conductor layer L1 is formed by the additive method in this manner, one surface of the substrate 20 is polished with the surface layer of the permanent resist 36 and the via holes 42 by belt sanding using # 600 belt polishing paper. (FIG. 3 (L)) until the top surface of the copper (electroless plating) 38 is aligned. Subsequently, buffing is performed to remove scratches caused by the belt sander (only buffing may be performed). Then, the other surface is polished in the same manner to form a printed wiring board having both surfaces smooth. This printed wiring board is connected to the signal line 40 by the power supply line 40P and the ground line 40G as described above with reference to FIG.
A configuration in which S is sandwiched was adopted.

(12) By repeating (2) to (11),
The multilayer printed wiring board is completed by building up the second conductor layer L2 including the line insulation layer 136, the interlayer insulation layer 130, and the outer copper pattern 140 (FIG. 3).
(M)).

In the multilayer printed wiring board shown in FIG. 4A, one signal line 40S is provided between the power supply line 40P and the ground line 40G.
It is also possible to arrange a signal line between P and P, and to arrange a signal line 40S between the ground line 40G and the ground line 40G.

Further, in the multilayer printed wiring board of the first embodiment, as shown in FIG. 4B, between the power supply line 40P and the ground line 40G, between the power supply line 40P and the power supply line 40P, or
It is also possible to arrange a plurality of signal lines 40S between the ground line 40G and the ground line 40G. By arranging a plurality of signal wirings in this manner, the ratio of signal lines in the wirings can be increased, and the density of the multilayer printed wiring board can be increased.

Next, a multilayer printed wiring board according to a second embodiment of the present invention will be described with reference to FIG. As described above with reference to FIGS. 1 to 3, in the multilayer printed wiring board according to the first embodiment, a high dielectric constant line insulating layer is provided between the inner copper patterns 28 formed directly on the substrate 20. Was not provided. On the other hand, as shown in FIG. 6, in the multilayer printed wiring board of the second embodiment, a high dielectric constant line insulating layer 29 is provided between the inner copper The talk is reduced, and the rise of the signal (pulse) waveform is improved.

[0035]

As described above, in the first aspect, since the dielectric constant of the material that insulates the layers is low, the coupling capacitance between the signal lines in the upper and lower layers is reduced, so that the cross between the signal lines in the upper and lower layers is reduced. Talk is reduced. In addition, since the material that insulates the signal lines of the same conductor layer has a high dielectric constant, the leakage of the electric field is reduced, and the rise of the signal waveform is accelerated.

According to a second aspect of the present invention, a plurality of signal lines are sandwiched between a power supply line and a ground line, or a power supply line or a ground line, thereby increasing the ratio of signal lines in the wiring and increasing the density of the multilayer printed wiring board. Can be achieved.

According to the third aspect of the present invention, since the material for insulating lines and the material for insulating layers are formed by adding inorganic particles to a resin, the dielectric constant can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a process chart showing the manufacture of a multilayer printed wiring board according to a first embodiment of the present invention.

FIG. 2 is a process chart showing the manufacture of the multilayer printed wiring board according to the first embodiment of the present invention.

FIG. 3 is a process chart showing the manufacture of the multilayer printed wiring board according to the first embodiment of the present invention.

FIGS. 4A and 4B are explanatory diagrams illustrating a configuration of a multilayer printed wiring board according to the first embodiment.

FIG. 5A and FIG. 5B are explanatory diagrams showing magnetic field line distribution and power line distribution according to the distance between a signal line and a power supply line.

FIG. 6 is an explanatory diagram illustrating a configuration of a multilayer printed wiring board according to a second embodiment.

FIGS. 7A and 7B are waveform diagrams showing transmission waveforms of pulses on a signal line.

8 (A), 8 (B), and 8 (C) are explanatory diagrams showing a configuration of a multilayer printed wiring board according to a conventional technique.

[Explanation of symbols]

 Reference Signs List 20 board 22 copper foil 28 inner layer copper pattern 30 interlayer insulating layer 36 inter-layer insulating layer 40 outer layer copper pattern 40S signal line 40G ground line 40P power supply line 42 via hole

Claims (3)

[Claims] 1. A structure in which a signal line is sandwiched between a power supply line and a ground line in the same conductor layer, or a signal line is surrounded by a power supply line or a ground line in the same conductor layer. The multilayer printed wiring board having the above-mentioned structure, wherein a material for insulating between lines has a higher dielectric constant than a material for insulating between layers. 2. The multilayer printed wiring board according to claim 1, wherein a plurality of signal lines are surrounded by a power line and a ground line, or a plurality of signal lines are surrounded by a power line and a ground line in the same conductor layer. 3. The multilayer printed wiring board according to claim 1, wherein the material for insulating between the lines and the material for insulating between the layers are formed by adding inorganic particles to a resin.