JP2003031944A - Multilayered printed wiring board and method of manufacturing line signal line thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board and a method of manufacturing its line signal lines which is superior in elevating the packaging density of the wiring board and mechanical strength and manufactures them with a few steps at a low cost. SOLUTION: The printed wiring board has a core board (100), formed by stacking a surface layer (20) on the surface of an inner board (10). At least a buildup layer (30) is formed on the surface of the core board, plating blind through-holes (22), for taking out line signal lines (11) formed on the inner board (10) surface are formed into the surface layer (20) of the core board, blind plating through-holes (31) for taking out line signal lines (21), formed on the surface of a surface layer of a core board (1100) are formed into the buildup layer (30), and only one buildup layer is stacked on the surface of the core board to form transmission lines L1-L3 of the three-layer structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board formed by laminating a plurality of glass cloth substrates, and more particularly to a line signal line forming structure in such a multilayer printed wiring board and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a multilayer printed wiring board which has its front surface or back surface used or has electronic components mounted therein at a high density is usually required to have the required mechanical strength and workability. And the like, it is formed by laminating a plurality of substrates made of a glass cloth material, and is called a core substrate or a core printed wiring board. The method for manufacturing such a multilayer printed wiring board is already known, for example, from Japanese Patent Laid-Open No. 2001-85843.

By the way, with the recent strong demand for miniaturization of electronic devices, as represented by, for example, mobile phones and notebook computers, high density is achieved even for printed wiring boards on which various electronic components are mounted. Is required. Therefore, as a high-density printed wiring board that meets such demands, for example, the 12th Circuit Assembly Academic Lecture Meeting "Examples of adoption of build-up printed wiring board in notebook computer", Akihiko Yakitani, Yasushi Masaoka, Yutaka Igarashi, Yasuo Kaneko , 2001 Japan Mounting Technology Roadmap, 200
According to the Japan Electronics and Information Technology Industries Association, published in March 1st, so-called build-up printed wiring boards are already known.

In the above-mentioned conventional technique, a metal plate (R) is formed by sticking a thin resin layer on one surface of a core substrate formed by laminating a plurality of so-called glass cloth materials.
CC: Resin Coated Copper) A problem with the transmission line in a known 1-2 layer connection build-up printed wiring board formed by laminating one build-up layer, specifically, a ground layer or a power supply layer. In order to solve the problems that the characteristic impedances are difficult to be equalized due to the difference in distance (that is, the characteristic impedances are different) and crosstalk noise is easily generated, two layers of RCC are laminated on the surface of the core substrate 1- It has a three-layer connection structure. That is,
In this 1-3 layer connection structure, the conductive layer formed between the surface of the core substrate and the first buildup layer (insulating layer) is L
3. A conductive layer formed between the buildup layer (insulating layer) and the second buildup layer (insulating layer) laminated thereon is L2, and on the surface of the second buildup layer. The formed conductive layer is L1, and these conductive layers are respectively L1 = signal layer and L2 = power source (or ground).
The layer, L3 = signal layer, has a three-layer structure.

[0005]

However, in the above-mentioned prior art, the following problems have still been pointed out.

That is, according to the above-mentioned conventional technique, the signal layers L1 and L2 forming the line signal line are structured so that the power source (or ground) layer L2 is sandwiched between them, so that the characteristic impedance can be improved. Although it is possible to achieve the sameness and suppress the generation of crosstalk noise, however, as described above, two resin layers (RCC) are laminated on the front surface and / or the back surface of the core substrate, respectively. Since it has a structure, there is a problem in mechanical strength as a completed printed wiring board. That is, the RCC layer is weak in strength with respect to the core substrate formed by laminating a plurality of substrates made of glass cloth material, and when the RCC layer is incorporated into an electronic device, for example, the mounting state becomes unstable. . Further, regarding the manufacturing process, there is also a problem that the working process is increased because laser processing, plating treatment, etching treatment and the like are sequentially repeated after laminating each RCC layer by a laminating press.

Therefore, in the present invention, in view of the above problems in the prior art, specifically, the characteristic impedance of the line signal line which is a transmission line that can be manufactured in a smaller number of steps can be obtained. An object of the present invention is to provide a multilayer printed wiring board capable of realizing the sameness and suppressing the generation of crosstalk noise, and a method for manufacturing a structure for taking out the line signal line thereof.

[0008]

In order to achieve the above-mentioned object, according to the present invention, first, a surface layer is laminated on the surface of an inner substrate on which a line signal line is formed, and a line signal is formed on the surface of the surface layer. A core substrate comprising at least two layers of layers formed with lines, and a multilayer printed wiring board having at least one buildup layer formed on the surface of the core substrate, wherein the surface layer of the core substrate of the two stages Has a first non-through hole for taking out a line signal line formed on the surface of the inner substrate, and the build-up layer has a line signal formed on the surface of the surface layer of the core substrate. A second non-penetrating through hole for taking out the wire is formed, and thus, on the surface of the substrate, the surface of the two-stage core substrate, and the surface of the build-up layer, respectively.
The present invention provides a multilayer printed wiring board having line signal lines.

According to the present invention, in the above-mentioned multilayer printed wiring board, the core substrate composed of the two layers is
Line signal lines are also formed on the back surface of the inner substrate, and a back layer is laminated on the back surface to form a three-stage core substrate.
At least one other build-up layer is also formed on the back surface of the back layer, and the back layer of the three-stage core substrate is
A third non-penetrating through hole for taking out the line signal line formed on the back surface of the inner substrate is formed, and the other build-up layer is formed on the surface of the back layer of the three-stage core substrate. A fourth non-penetrating through hole for taking out the line signal line is formed.
Line signal lines may be formed on the back surface of the three-stage core substrate and the front surface of the other buildup layer, respectively.

Further, in the present invention, in the above-mentioned multilayer printed wiring board, the through-holes for connecting the upper and lower surfaces of the three-stage core board are formed, or the upper and lower surfaces of the core board are connected. It is preferable that the plated through hole is set to the ground potential.

In addition, according to the present invention, also in order to achieve the above object, in the multilayer printed wiring board in which a plurality of substrates having line signal lines are laminated to form a core substrate, the line signal lines are provided. And (B) forming a non-through hole by laser processing on the surface layer of the core substrate; and (B) plating the non-through hole formed on the surface layer of the core substrate to form a non-through hole. Forming a through-hole; (C) forming a build-up layer on the surface of the core substrate on which the non-through-hole is formed; (D) forming a non-through hole by laser processing on the surface of the build-up layer;
(E) The non-penetrating holes formed in the build-up layer are plated to form non-penetrating through holes, and thus the line signal line formed on the lower surface of the surface layer of the core substrate having the plated through holes is formed as described above. A method of manufacturing a line signal line of a multilayer printed wiring board is provided, which is taken out to the surface of a core substrate and then the line signal line formed on the surface of the surface layer of the core substrate is taken out to the surface of the buildup layer.

In the present invention, in the above-mentioned manufacturing method, it is preferable that, in the step (A), the laser processing for forming the through hole in the surface layer of the core substrate is performed by a carbon dioxide gas laser.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. First, FIG. 1 shows the internal structure of a multilayer printed wiring board according to an embodiment of the present invention by its cross section.

In FIG. 1, reference numeral 100 is a so-called
The core substrate 100 is a core substrate, and the core substrate 100 is a single-layer substrate made of a glass cloth material (glass cloth resin-impregnated cloth) called FR-4 or the like, or a plurality of laminated substrates.
It is a so-called printed wiring board that uses the front surface or the back surface, or has inside thereof, although not shown, for example, active elements such as ICs, electronic components including chip capacitors, chip resistors and the like are mounted at high density. is there. The inner substrate 10 forming the core substrate 100 has a first line signal line 11 formed on its surface, and a substrate made of another glass cloth material is laminated on the surface. Thus, the surface layer 20 is formed. In addition, the surface layer 20
The second line signal line 21 is also formed on the surface of the. That is, these laminated substrate 10 and surface layer 20 are laminated.
Thus, the core substrate 100, which is a substrate made of a multi-layer glass cloth material, is configured.

In the structure of the line signal line in the multilayer printed wiring board according to the present invention, the core substrate 100 described above is used.
A build-up layer 30, which will be described in detail below, is formed on the surface of the surface layer 20. In addition, the core substrate 10
In the surface layer 20 of 0, so-called non-penetrating through holes 22 are formed corresponding to the line signal lines 11 formed on the surface of the inner substrate 10 and taken out, and further, in the buildup layer 30 described above, Although not shown, the core substrate 100
The non-penetrating through holes 31 are also formed in correspondence with the positions of the line signal lines formed on the surface of or the extracted line signal lines 21. In addition,
Reference numeral 32 in the figure is a line signal line formed on the surface of the build-up layer 30.

In the multilayer printed wiring board shown in FIG. 1, the plated through holes 110 are formed so as to penetrate both the upper and lower surfaces of the core substrate 100. When the build-up layer 30 is formed on the surface of the resin, a part of the resin will enter and be filled therein by heating and pressurizing.

By the way, according to the structure of the line signal lines in the above-mentioned multilayer printed wiring board according to the present invention, as is apparent from FIG.
0 is the back side of the surface layer 20, that is, the conductive layer formed on the surface of the inner substrate 10 constituting the core substrate 100 is the line signal layer L3, and the conductive layer formed on the surface of the core substrate 100 is the line signal layer L2. The conductive layer formed on the surface of the build-up layer 30 is used as the line signal layer L3 to form a so-called three-layer transmission line. In this example, the plated through holes 110 formed through both upper and lower surfaces of the core substrate 100 are connected to the power supply potential or the ground (ground) potential via the conductive layer 101 formed on the lower surface of the core substrate 100. , And the line signal layer L2 formed on the surface of the core substrate 100 is used as a power source or a ground layer. Thus, the structure of the line signal line in the multilayer printed wiring board of the present invention is
Similar to the above-mentioned 1-3 layer connection structure according to the conventional technology, two line signal layers (L1 = signal layer, L3 = signal layer) are arranged with a power (or ground) layer = L2 interposed therebetween. It has a three-layer structure.

Next, the manufacturing process of the above-mentioned multilayer printed wiring board according to the present invention, especially the line signal line thereof, will be described with reference to the attached FIG.

First, as shown in FIG. 3 (A), an inner substrate 10 having a predetermined circuit pattern and lands for mounting components (indicated by reference numerals 11 and 21 in the figure) formed on a surface thereof by a predetermined process. And the surface layer 20, and the prepreg 40 between them.
Then, the core substrate 100 is formed.

After that, as shown in FIG. 3B, a through hole 120 is formed in a part of the formed core substrate 100 by, for example, drilling or punching, and at the same time, a predetermined position of the surface layer 20 is formed. At a position (for example, a position where the line signal line 11 formed on the surface of the inner substrate 10 is to be taken out), a high output laser beam typified by, for example, a carbon dioxide gas laser (CO ₂ laser) is used to prevent non-penetration. The hole 130 is formed. In this example, the diameter of the through hole 120 formed by drilling or punching is 0.3 mm.
(However, the outer diameter of the plated through-hole electrode formed on the surface of the substrate is 0.5 mm), while the diameter of the non-through hole 130 formed by the carbon dioxide laser is 0.1 mm (however, it is formed on the surface of the substrate. The outer diameter of the plated through-hole electrode is 0.3 mm).

By the way, as described above, the carbon dioxide laser is utilized in the surface layer 20 forming a part of the core substrate 100, as described above. Because it is made of material. That is, when it is attempted to form the non-through holes 130 in the glass cloth resin-impregnated cloth forming the surface layer 20 with normal laser light, the glass fibers inside the non-through holes 130 are not melted, and the so-called, This is because it remains as “burrs” and the plating process cannot be applied to the inside as it is. Therefore, in order to form a good non-penetrating plated through hole by the subsequent plating process without leaving the above-mentioned burr inside the non-through hole 130 formed by the laser beam, as described above, the carbon dioxide gas laser (CO It is preferable to use a high-power laser beam represented by _two lasers. In the above example, the through hole 120 is described as being formed by drilling or punching, but the present invention is not limited to this, and the through hole 1 is not limited thereto.
20 may also be formed by a high-power laser beam such as a carbon dioxide laser.

Subsequently, as shown in FIG. 3C, the core substrate 100 obtained above is plated to form the through holes 120 of the core substrate 100 as the plated through holes 110 and the surface layer 20. Forms a non-penetrating plated through hole 22. After that, in order to form the build-up layer 30 on the surface thereof, a resin layer to be a thin insulating film is formed on one surface thereof by, for example, a screen printing method, a curtain coater method, a roll coater method, an electrostatic coating method, or the like. Then, the non-through hole 130 is formed in the resin layer of the buildup layer 30 formed as described above by laser light.

Then, as shown in FIG. 3D, a predetermined circuit pattern and a non-through plating through hole 31 are formed on the surface of the build-up layer 30 and the non-through hole 130 by electroless plating. That is, the non-through plating through hole 31 is formed at the position where the line signal line 21 formed on the surface of the core substrate 100 is to be taken out by the build-up method of the insulating resin layer and the additive plating method.

In addition, one layer of a metal plate (RCC: Resin Coated Copper) formed by sticking a thin resin layer on one surface of the core substrate 100 formed in FIG. 3C is heated and heated under pressure. May be joined together. That is,
Also by this, a laminated RCC resin layer can be formed on the surface of the core substrate 100.

After that, a predetermined circuit pattern is formed on the surface of the laminated RCC by etching or the like, and a part thereof (for example, the position where the line signal line 21 formed on the surface of the core substrate 100 is to be taken out). ), A non-through hole is formed by ordinary laser processing. afterwards,
Further, a plating process is performed to form the non-penetrating plated through holes 31 on the RCC laminated on the surface of the core substrate 100.

Next, the electrical connection structure of the line signal lines of the multilayer printed wiring board manufactured as described above will be described in detail with reference to the attached FIGS. 4 to 6.

First, in FIGS. 4A and 4B, the line signal line of the line signal layer L1 formed on the surface of the buildup layer 30 laminated on the surface of the core substrate 100 as described above. 32 is shown, which are formed adjacent to each other and in parallel. And, in particular, FIG.
In (A), as is clear from the figure, these line signal lines 32 are respectively connected to the non-through plated through holes 31 electrically connected on the surface of the buildup layer 30.
And the surface layer 2 forming the uppermost layer of the core substrate 100.
Through the non-through plating through hole 22 formed in 0,
It is connected to the line signal line 11 forming the line signal layer L3 formed on the surface of the inner substrate 10 which is the inner layer of the core substrate 100.

On the other hand, in FIG. 4B described above, as is clear from the figure, the line signal lines 32 of the line signal layer L1 formed on the surface of the buildup layer 30 are respectively formed in the buildup layer 30. It is connected to the line signal line 21 forming the line signal layer L2 formed on the surface of the core substrate 100 via the non-through plated through hole 31 electrically connected on the surface.

Further, FIG. 5 attached herewith shows a core substrate 100.
The line signal lines 21 forming the line signal layer L2 formed on the surface of the core substrate 100 are shown. As is clear from this figure, these line signal lines 21 respectively form the uppermost layer of the core substrate 100. The line signal layer L formed on the surface of the substrate 10, which is the inner layer of the core substrate 100, through the non-through plated through holes 22 formed in the surface layer 20.
2 is connected to the line signal line 11 forming the line 2.

Further, the attached FIG. 6 shows the build-up layer 3
Along with the line signal line 32 of the line signal layer L1 formed on the surface of 0, the line signal line 11 forming the line signal layer L3 formed on the surface of the inner substrate 10 which is the inner layer of the core substrate 100 is formed. It is shown.

Then, as is apparent from FIGS. 4 to 6, 1 is formed on the surface of the core substrate 100 as described above.
The line signal line of the multilayer printed wiring board manufactured by laminating the build-up layers (insulating layers) 30 of the layers is first composed of the inner substrate 10 forming the core substrate 100 and the surface layer 20 laminated on the surface thereof. Line signal layer L3 in between, and
A line signal layer L2 is provided between the core substrate 100 and the buildup layer (insulating layer) 30, and a line signal layer L1 is further provided on the surface of the buildup layer (insulating layer) 30.
Each is formed, that is, has a three-layer structure of L1 to L3.

As described above, according to the structure of the multilayer printed wiring board of the present invention and the method of manufacturing the line signal line thereof, even if the wiring board is made higher in density, the characteristic impedances thereof are made the same and the crosstalk noise is increased. The transmission line capable of suppressing the occurrence of the above is formed by only stacking one build-up layer on the surface of the core substrate, that is, in a smaller number of steps as compared with the conventional 1-3 layer connection structure. It can be manufactured at low cost. In this case, in the above three-layer structure of the line signal layer, for example, as shown in the attached FIG. 2, the central line signal layer L2 is a ground (or power supply) layer, and line signals are provided above and below the line signal layer L2. The layers L1 and L3 will be arranged. That is, according to the transmission line having such a three-layer structure, the line signal layers L1 and L3 are arranged at substantially equal distances with respect to the central line signal layer L2. The occurrence will be suppressed. Therefore, the core substrate 1
The thickness of the surface layer 20 of 00 is equal to the thickness of the build-up layer (insulating layer) 30 described above, or the same characteristic impedance is obtained in consideration of the difference in the dielectric constant and the like.
It is preferable to appropriately design and select.

Further, FIG. 7 attached herewith shows a multilayer printed wiring board according to another embodiment of the present invention by its sectional structure. As is clear from this figure, the multilayer printed wiring boards according to other embodiments are
A transmission line is further formed on the lower surface side of the multilayer printed wiring board described above. Specifically, another one buildup layer (insulating layer) 30 ′ is further laminated on the back surface of the core substrate 100 described above, and the bottom layer 20 ′ of the lowermost layer of the core substrate 100 is also non-coated. Through-plated through-holes 22 'are formed and the build-up layer 3 is formed.
A non-through plating through hole 31 'is also formed in 0'.

Even in the multilayer printed wiring board having the above structure, the inner (second layer from the bottom) substrate 1 forming the core substrate 100 is similar to the above-described electrical connection structure.
A line signal layer L3 ′ is provided between 0 ′ and the back layer 20 ′ laminated on the back surface thereof, and a line signal layer L2 ′ is provided between the core substrate 100 and the other buildup layer 30 ′. Then, a line signal layer L1 'is formed on the back surface of the other buildup layer 30', thereby forming a three-layer structure of L1 'to L3'. As for the electrical connection, as shown in FIG. 2, the central line signal layer L2 ′ is used as a ground (or power supply) layer, and the line signal layers L1 ′ and L3 ′ are provided above and below the line signal layer L2 ′. Is preferably arranged.

In the multilayer printed wiring board according to the present invention described variously above, the build-up layers laminated on the front surface and / or the back surface of the core substrate formed by laminating a plurality of substrates made of glass cloth material are Since only one layer is required for each, the multilayer printed wiring board obtained by laminating these (these) build-up layers is superior to the above-mentioned prior art wiring board in terms of mechanical strength. It will be apparent to those skilled in the art that the above will be excellent. Also from this, it is possible to obtain the effect of improving the quality of the multilayer printed wiring board, the accuracy of the manufacturing process such as drilling and positioning, and improving the yield and the mounting rate in mounting the components. Becomes

[0036]

As is apparent from the above detailed description, according to the method for manufacturing a multilayer printed wiring board and its line signal line according to the present invention, even if the wiring board is made higher in density, It is possible to manufacture a transmission line that can suppress the occurrence of crosstalk noise at a low cost with fewer steps by stacking only one build-up layer on the surface of the, and making its characteristic impedance the same. Further, the produced multilayer printed wiring board also has an excellent effect of having excellent mechanical strength due to its structure.

[Brief description of drawings]

FIG. 1 is a sectional view showing an internal structure of a multilayer printed wiring board according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of an electrical connection structure of line signal lines of line signal layers L1 to L3 in the multilayer printed wiring board.

FIG. 3 is a cross-sectional view for explaining the manufacturing process of the line signal line in the multilayer printed wiring board of the present invention.

FIG. 4 is a diagram particularly illustrating the electrical connection structure of the line signal line of the line signal layer L1 in the multilayer printed wiring board manufactured as described above.

FIG. 5 is a diagram particularly illustrating an electrical connection structure of line signal lines of the line signal layer L2 in the multilayer printed wiring board manufactured as described above.

FIG. 6 is a diagram particularly illustrating an electrical connection structure of the line signal line of the line signal layer L3 in the multilayer printed wiring board manufactured as described above.

FIG. 7 is a cross-sectional view showing the internal structure of a multilayer printed wiring board according to another embodiment of the present invention.

[Explanation of symbols]

100 core substrate 10 Inside board 11, 21, 32 line signal line 20 surface 22, 31 Non-penetrating plated through hole 30 Build-up layer 110 through hole L1 to L3 line signal layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kiyoshi Ozeki             1-31-1 Nishigotanda, Shinagawa-ku, Tokyo Sun             Standing AIC Co., Ltd. (72) Inventor Kenshiro Fukusato             1065 Kugeta, Ninomiya-cho, Haga-gun, Tochigi Prefecture             Hitachi AIC Co., Ltd. (72) Inventor Yasuhiro Iwasaki             1065 Kugeta, Ninomiya-cho, Haga-gun, Tochigi Prefecture             Hitachi AIC Co., Ltd. F-term (reference) 5E346 AA04 AA12 AA15 AA43 BB02                       BB06 CC04 CC09 CC32 DD02                       DD03 DD12 DD23 DD33 EE33                       FF07 FF13 GG15 GG17 GG28                       HH03 HH11

Claims (5)

[Claims] 1. A core substrate having at least two layers in which a surface layer is laminated on the surface of an inner substrate on which line signal lines are formed and line signal lines are formed on the surface of the surface layer, and a core substrate of the core substrate. In a multilayer printed wiring board having at least one build-up layer formed on a surface thereof, a line signal line formed on a surface of the inner substrate is taken out as a surface layer of the two-stage core substrate. A non-penetrating through hole is formed, and a second non-penetrating through hole for taking out a line signal line formed on the surface of the surface layer of the core substrate is formed in the build-up layer. A multi-layer printed wiring board, wherein line signal lines are formed on the surfaces of the two-stage core substrate and the surface of the build-up layer, respectively. 2. The multilayer printed wiring board according to claim 1, wherein the core substrate composed of the two layers has line signal lines formed on the back surface of the inner substrate and a back layer on the back surface. To form a three-stage core substrate, at least one other build-up layer is formed on the back surface of the back layer, and the inner layer of the inner substrate is formed on the back layer of the three-stage core substrate. A third non-through hole for taking out the line signal line formed on the back surface is formed, and the line signal line formed on the surface of the back layer of the three-stage core substrate is formed in the other buildup layer. Fourth non-penetrating through holes to be taken out are formed, and thus line signal lines are formed on the back surface of the inner substrate, the back surface of the three-stage core substrate, and the front surface of the other buildup layer, respectively. Multi layer pre Wiring board. 3. The multilayer printed wiring board according to claim 2, wherein plated through holes that connect the upper and lower surfaces of the core substrate are formed in the three-stage core substrate. Board. 4. The multilayer printed wiring board according to claim 3, wherein the plated through holes connecting the upper and lower surfaces of the core substrate are at ground potential. 5. A method for producing the line signal line in a multilayer printed wiring board, comprising a plurality of substrates having line signal lines formed thereon to form a core substrate, comprising: (A) the core substrate. Forming a non-through hole by laser processing on the surface layer of (B); plating the non-through hole formed on the surface layer of the core substrate to form a non-through hole; (C) forming the non-through hole Forming a build-up layer on the surface of the core substrate; (D) forming a non-through hole on the surface of the build-up layer by laser processing; and (E) plating the non-through hole formed on the build-up layer. To form a non-penetrating through hole, so that the line signal line formed on the lower surface of the surface layer of the core substrate having the plated through hole is taken out to the surface of the core substrate, and the core substrate is Method for producing a line signal line for a multilayer printed wiring board surface layer of the line signal lines formed on the surface, characterized in that retrieving the surface of the buildup layer of.