JP2001024340A - Manufacture of printed wiring board and the printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board where disconnection is not generated in the direction of board thickness. SOLUTION: A first reinforcing pattern 14a and a first circuit pattern 14b are formed on a conductor plate 14 of the upper surface side of a first core member 15, and a second reinforcing pattern and a second circuit pattern are formed on a conductor layer 21 of the lower surface side of a second core member. Each of the reinforcing patterns is made into a shape, capable of preventing contraction in the surface direction of the board without exerting electrical influence on each of the circuit patterns. Conductive pillars 16, 16, etc., of almost conical types are formed on the first circuit pattern 14b. After an insulating board 30 which is yet to be cured is interposed between the conductive pillars 16, 16, etc., and the conductor layer 21 and pressed, the insulating board 30 is cured, and the outer peripheral edge of the obtained multilayer board is trimmed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board, and more particularly to a printed wiring board constituting a so-called multilayer board and a method of manufacturing the printed wiring board.

[0002]

2. Description of the Related Art Conventionally, as one method of forming a multilayer board, a prepreg, that is, an uncured insulating substrate made of a sheet-like thermosetting resin such as an epoxy resin, is coated with a conductive material such as a metal powder in a resin. The conductive layer provided with conductive pillars formed into a substantially conical shape by dispersing the conductive pillars into the prepreg penetrates the conductive pillars, thereby providing electrical conduction in the thickness direction of the insulating substrate. Is formed.

FIG. 11 is a diagram schematically showing a method of forming an electrical connection of an insulating substrate by penetrating conductive pillars (hereinafter, this method is simply referred to as “penetration method”).

As shown in FIG. 11, in this penetration method,
A plurality of substantially conical conductive pillars 102, 102,... Are formed on the first conductive layer 101.
The prepreg 103 of an insulating substrate is provided on the upper side of 2, 102,.
Are arranged (FIG. 11A). Thereafter, the first conductor layer 101 and the prepreg 103 are pressed, and the conductive pillars 102, 102,... Are made to penetrate the prepreg 103. In this state, the prepreg 103 is heated or the like.
To cure.

Next, a second conductor layer 104 is formed on the upper surface of the prepreg 103 in the figure, and is called a “core material”.
Basic elements of a printed wiring board in which conductor layers are formed on both surfaces of an insulating substrate are formed. In order to form a multilayer board, such core materials are laminated via another prepreg to form a multilayer.

[0006]

However, in general, the conductor layer is a metal layer such as a copper foil, and the insulating substrate is made of a resin material such as an epoxy resin, and the two have different coefficients of thermal expansion.
When two material layers with different coefficients of thermal expansion are laminated and heated,
Since each layer expands and contracts at a different rate, distortion occurs at the interface between the layers, which triggers the bending of the substrate and the displacement between the insulating substrate and the conductor layer.

When the substrate is bent or a gap between the insulating substrate and the conductor layer occurs, the conductive pillar 102 and the conductor layer 10
There is a problem in that the contact with 1,104 is broken, the electrical conduction is lost, and the function as a multilayer board suffers a fatal impact. In particular, in the case of a substrate employing the penetration method, both the insulating substrate and the conductor layers 101 and 104 are formed thin in order to meet the demand for high integration. There is a problem that disconnection easily occurs.

The present invention has been made to solve such a problem. That is, an object of the present invention is to provide a printed wiring board and a method for manufacturing the printed wiring board which do not cause disconnection in the thickness direction of the board.

[0009]

SUMMARY OF THE INVENTION The method of the present invention comprises the steps of forming a first reinforcing pattern and a first circuit pattern on a first surface of a first core material; Forming a second reinforcing pattern and a second circuit pattern on the second surface, forming a substantially conical conductive pillar on the first circuit pattern, and interposing an uncured insulating substrate. Inserting the first surface and the second surface so as to face each other, and pressing the first core material, the insulating substrate, and the second core material so that the conductive material is applied to the insulating substrate. A step of electrically connecting the first circuit pattern and the pattern of the second circuit with each other, and a step of curing the insulating substrate to form a multilayer substrate. .

In the above invention, the term "core material" refers to a material obtained by forming a conductive layer on the surface of an insulating substrate, and includes both a material formed by a penetration method and a material formed without a penetration method. .

In the above invention, the circuit pattern is a pattern for forming an electric circuit required when a semiconductor element or the like is mounted.

On the other hand, the reinforcing pattern is a pattern for mechanically reinforcing the substrate to prevent deformation such as shrinkage or bending of the substrate during heating, and does not electrically affect the circuit pattern. Form into a shape or form. As an example of the reinforcing pattern, for example, a frame-like pattern formed in a work area formed on an outer peripheral edge of the circuit pattern, and the like can be given. Further, an intermittent portion for venting gas may be formed in this frame-shaped pattern.

Further, another method of the present invention includes a step of forming a substantially conical conductive pillar on the first conductive layer, and a step of disposing an uncured insulating substrate on the conductive pillar. ,
Pressing the first conductor layer and the insulating substrate to allow the conductive pillar to penetrate the insulating substrate; and forming a second conductor on the surface of the insulating substrate through which the tip of the conductive pillar has penetrated. Forming a layer, forming a first reinforcing pattern and a first circuit pattern on the first conductive layer, and forming a second reinforcing pattern and a second circuit pattern on the second conductive layer.
Forming a circuit pattern, and curing the insulating substrate.

In the above method, the core material is formed.
A multilayer board can be formed by the above method using a plurality of the core materials.

In such a core material, the ratio of the occupied area of the circuit pattern formed on the first surface of the insulating substrate is close to the ratio of the occupied area of the circuit pattern formed on the second surface. Is desirable. This is because if the occupied area of the circuit pattern is close on both sides of the insulating substrate, the shrinkage ratio on each side becomes close, and the force for deformation is offset. Specifically, it is desirable that the difference in the ratio of the occupied area is in the range of 0 to 5% between the first surface and the second surface of the insulating substrate.

The reason why the preferable range of the difference in the ratio of the occupied area of the pattern is set to the above range is that if the range exceeds or falls below this range, a problem arises in that the insulating substrate is warped toward a denser conductor. Because.

On the other hand, if the conductor occupying area is small, the shrinkage of the substrate will increase.

Further, a multilayer board can be formed by further laminating the core material formed by this method. For example, the following method is used.

Forming a substantially conical conductive pillar on the first conductive layer; and forming an uncured first conductive pillar on the conductive pillar.
Disposing an insulative substrate; pressing the first conductive layer and the first insulative substrate to penetrate the conductive pillar through the first insulative substrate; The surface of the insulating substrate through which the tip of the conductive pillar penetrates,
Forming a first conductive layer; and forming a first conductive layer on the first conductive layer.
Forming a second reinforcing pattern and a second circuit pattern on the second conductor layer.
Forming a first core material by curing the insulating substrate; and forming a substantially conical second conductive pillar on the second circuit pattern. Disposing an uncured second insulating substrate on the second conductive pillar; and pressing the first core material and the second insulating substrate to form the second insulating substrate. A step of penetrating the second conductive pillar through an insulating substrate;
Forming a third conductive layer on the surface of the insulating substrate through which the tip of the second conductive pillar penetrates; and forming a third reinforcing pattern and a third circuit pattern on the third conductive layer. A method for manufacturing a printed wiring board, comprising: a step of forming; and a step of curing the second insulating substrate to form a multilayer substrate.

According to the present invention, since the reinforcing pattern is formed, the substrate is prevented from being bent or displaced in the surface direction due to contraction or expansion during heating. As a result, electrical disconnection in the thickness direction of the insulating substrate is prevented.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, a method for manufacturing a printed wiring board according to an embodiment of the present invention will be described. FIG. 1 is a vertical sectional view schematically illustrating a procedure for manufacturing a printed wiring board according to the present embodiment, and FIG. 2 is a flowchart illustrating the procedure.

First, as shown in FIG. 1, a core material, that is, an insulating substrate provided with conductor layers on both surfaces thereof is prepared. FIG.
As shown in FIG. 2A, a thin conductor as a first conductor layer, for example, a thin conductor plate 1 such as a copper foil is prepared (S).
(STEP1), a plurality of substantially conical conductive pillars 2, 2,... Are formed on the conductive plate 1 along a predetermined circuit pattern by printing or the like (FIG. 1B / STEP2). Thereafter, an uncured insulating substrate (prepreg) 3 is arranged on the conductive pillars 2, 2,... (FIG. 1 (c) / S).
TEP3). Then, the conductor plate 1 and the insulating substrate 3 are pressed to apply the conductive pillars 2, 2, 2 to the insulating substrate 3.
(FIG. 1 (d) / STEP4). Further, a metal layer as a second conductor layer, for example, a copper foil layer 4 is formed on the surface of the insulating substrate through which the tips of the conductive pillars 2, 2,. FIG. 1 (e)
/ STEP5). Thereafter, the insulating material 3 is cured by heating or the like to complete the core material 5 (STEP).
6).

FIG. 3 shows the uncured core material 5 thus obtained.
Is a partially enlarged perspective view of a section taken along a plane passing through vertices of conductive pillars 2, 2,....

As shown in FIG. 3, in the core member 5, flat conductor plates 1 and 4 are provided on the upper and lower surfaces of an uncured insulating substrate (prepreg) 3, and these conductor plates 1 and conductors are provided. The plate 4 is electrically connected to a substantially conical conductive pillar 2, 2,. In this core material 5, the prepreg 3 is cured while being sandwiched between the two conductor plates 1 and 4, so that the conductor plates 1 and 4 serve as a reinforcing material, and the core material 5 is prevented from bending or deforming.

Next, a description will be given of a process of manufacturing a multilayer board further multilayered using such a core material 5. FIG. 4 is a vertical sectional view illustrating a procedure for manufacturing the multilayer board, and FIG. 5 is a flowchart illustrating the procedure.

First, as shown in FIG. 4A, a core material 15 as a first core material is prepared (STEP 8), and a first reinforcing member is attached to a conductor plate 14 as a first surface of the core material 15. A pattern and a first circuit pattern are formed by a method such as an etching process (STEP 9).

FIG. 6 is a plan view of the core material 15. As shown in FIG. 6, the conductor plate 1 disposed on the upper surface side of the core material 15
4, a first reinforcement pattern 14a and a first circuit pattern 14b are formed. Although the first reinforcement pattern is formed on the entire shaded portion shown in the figure, the first circuit pattern 14b is shown in a lattice shape only, and the details of the pattern are omitted.

Similarly, the same core material 25 as the first core material 15 is used.
Is prepared, and the conductor plate 2 as a second surface of the core material 25 is prepared.
First, a second reinforcement pattern and a second circuit pattern are formed by a method such as an etching process (STEP 9). Although not shown, the second reinforcing pattern and the second reinforcing pattern similar to the first reinforcing pattern 14a and the first circuit pattern 14b are provided on the conductor plate 24 disposed on the lower surface side of the core material 25.
Circuit pattern is formed.

Next, as shown in FIG.
A plurality of substantially conical conductive pillars 16, 16, ... at predetermined positions along the first circuit pattern 14b formed by
Is formed by a printing technique or the like (STEP 10). Thereafter, as shown in FIG. 4C, the uncured insulating substrate 3
. 0 are inserted between the first core material 15 and the second core material 25 and the second circuit formed on the lower surface side of the conductive pillars 16, 16,. The pattern and the pattern are arranged to face each other (STEP 11).

In this state, the first pillar 15, the insulating substrate 30, and the second core 25 are pressed to allow the conductive pillars 16, 16,... To penetrate the insulating substrate 30. Thereby, the first circuit pattern 14b is electrically connected to the second circuit pattern formed on the conductor plate 21 (FIG. 3D / STEP 12). At the same time, the insulating substrate 30 is cured by heating or the like (STEP 13).

FIG. 7 is a plan view of the multilayer board 40 thus obtained. 7, details of the circuit pattern are omitted as in FIG. The multilayer board 40 thus obtained is cut (trimmed) on a vertical plane passing through the dotted line in the figure, and the work area formed on the outer peripheral edge is cut out and removed. This trimming removes part or all of the reinforcing pattern.
FIG. 8 is a perspective view of a vertical section passing through the apexes of the conductive pillars 16, 16,... Of the finished product of the multilayer board 40 obtained by trimming.

As described above, according to the method of the present invention, since the reinforcing pattern is formed on the two conductor plates 14 and 21 which sandwich the uncured insulating substrate (prepreg) 30, the insulating pattern is formed. When the conductive substrate 30 is cured by heating, the reinforcing pattern functions to prevent the insulating substrate 30 from shrinking in a direction parallel to the surface of the insulating substrate 30, that is, in the left and right directions in the figure. Therefore, the bending of the multilayer board 40 caused by the shrinkage and the displacement in the substrate surface direction between the insulating board and the conductor board are prevented. By preventing the bending and the displacement, the contact between the conductive pillar and the conductor plate is not broken, the disconnection in the thickness direction of the multilayer plate 40 is prevented, and the reliability as the multilayer plate is reduced. improves.

Further, when forming a circuit pattern such that the area occupancy of the circuit pattern disposed on both surfaces of the insulating substrate is as small as possible between the back surface and the front surface of the insulating substrate, Due to the difference in the coefficient of thermal expansion, the force acting between the insulating substrate and the conductor plate forming the circuit pattern is close to the front surface and the rear surface of the insulating substrate, and these cancel each other out so that apparent bending does not occur. Therefore, bending and deformation of the multilayer board are prevented, and disconnection in the thickness direction of the board and displacement of the laminated insulating boards and circuit patterns in the board surface direction are prevented, so that the reliability of the multilayer board is improved. In addition, since the shrinkage and displacement of the substrate when mounting various semiconductor elements on the multilayer board are prevented, the reliability at the time of mounting is improved.

(Second Embodiment) The second embodiment of the present invention will be described below.
As an embodiment of the present invention, a method of sequentially forming multiple layers from the core material will be described. Note that, in the present embodiment, the description of the same parts as those in the first embodiment will be omitted.

FIG. 9 is a vertical sectional view showing a procedure for sequentially forming multiple layers based on a core material, and FIG. 10 is a flowchart showing the procedure.

First, as shown in FIG.
Is prepared (STEP 8 '). This core material 35 is the same core material as used in the first embodiment. Next, a first reinforcing pattern 34a and a first circuit pattern 34b are formed on the conductor plate 34 on the upper surface side of the core material 35 by a technique such as etching (STEP 9 '). The first reinforcement pattern 34a formed here and the first circuit pattern 3
4b is the same as the first reinforcing pattern 14a and the first circuit pattern 14b formed in the first embodiment, respectively.

Next, a plurality of substantially conical conductive pillars 36, 3 are provided at predetermined positions on the first circuit pattern 34b.
Are formed by a printing technique or the like (FIG. 7B / ST).
EP10 '). Next, as shown in FIG. 9C, an uncured insulating substrate (prepreg) 40 is arranged on the conductive pillars 36, 36,... (STEP 11 '). In this state, by pressing the core material 35 and the insulating substrate 40, the conductive pillars 36, 36,.
0 (FIG. 7 (d) / STEP 12 '). At this point, the tips of the conductive pillars 36, 36,... Penetrate the insulating substrate 40 and are exposed on the upper surface in the figure.
Next, a conductor layer 50 is formed on the upper surface of the insulating substrate 40 by a plating technique or the like (STEP 13 '). Thereafter, the insulating substrate 40 is cured by heating or the like (STEP
14 '). Next, a circuit pattern and a reinforcing pattern are further formed on the conductor layer 50 (STEP 15 ').

When the multilayer board 60 thus formed is sufficiently multilayered, trimming is performed (STEP 17 '), and the process is terminated (STEP 1).
8 ').

On the other hand, if further multilayering is required, the above steps (STEPs 10 'to 15') are repeated.

When a multilayer board having a desired layer is obtained by repeating these operations (STEP 16 ′), the above-mentioned first layer is obtained.
The outer peripheral edge is trimmed in the same manner as in the first embodiment (ST
EP17 '), the conductor layers 31, 34, 50, ...
Is obtained (STEP 18 ').

According to the invention of this embodiment, since the insulating substrate and the conductor layer are laminated one by one, a multilayer board of a desired hierarchy can be formed.

[0042]

According to the present invention, since the reinforcing pattern is formed, the substrate is prevented from being bent or displaced in the surface direction due to contraction or expansion during heating. As a result, electrical disconnection in the thickness direction of the insulating substrate is prevented.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view schematically illustrating a procedure for manufacturing a printed wiring board according to an embodiment.

FIG. 2 is a flowchart of a procedure for manufacturing a printed wiring board according to the embodiment.

FIG. 3 is a partially enlarged perspective view of a portion of the core material according to the present embodiment cut along a plane passing through a vertex of a conductive pillar.

FIG. 4 is a vertical sectional view illustrating a manufacturing procedure of the multilayer board according to the embodiment.

FIG. 5 is a flowchart of a manufacturing procedure of the multilayer board according to the embodiment.

FIG. 6 is a plan view of a completed core material according to the embodiment.

FIG. 7 is a plan view of the multilayer board according to the embodiment.

FIG. 8 is a perspective view of a vertical cross section passing through the apex of a conductive pillar of a finished product of a multilayer board obtained by trimming.

FIG. 9 is a vertical cross-sectional view showing a procedure for sequentially forming multiple layers based on a core material according to a second embodiment of the present invention.

FIG. 10 is a flowchart of a procedure for sequentially forming multiple layers based on a core material according to a second embodiment of the present invention.

FIG. 11 is a vertical cross-sectional view of a core material schematically illustrating a method of forming an electrical conduction of an insulating substrate by penetrating conductive pillars.

[Explanation of symbols]

 5 core material, 4 conductor plate (first conductor layer), 14a first reinforcement pattern, 14b first circuit pattern, 2 conductive pillar, 30, 40 ... an insulating substrate.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E346 AA06 AA11 AA12 AA15 AA22 AA24 AA32 AA35 AA43 BB01 BB16 BB20 DD02 DD12 DD32 EE02 EE06 EE14 FF24 FF35 GG28 HH07

Claims (6)

[Claims] A step of forming a first reinforcing pattern and a first circuit pattern on a first surface of a first core material; and a step of forming a second reinforcing pattern and a second circuit pattern on a second surface of a second core material. Second
Forming a substantially pillar-shaped conductive pillar on the first circuit pattern; interposing an uncured insulating substrate with the first surface and the second surface;
And a step of pressing the first core material, the insulating substrate, and the second core material to cause the conductive pillar to penetrate the insulating substrate, thereby forming the first core material, the insulating substrate, and the second core material. Electrically connecting the circuit pattern to the pattern of the second circuit, and curing the insulating substrate to form a multi-layer substrate. . A step of forming a substantially conical conductive pillar on the first conductive layer; a step of disposing an uncured insulating substrate on the conductive pillar; Pressing an insulating substrate and allowing the conductive pillar to penetrate the insulating substrate; and forming a second conductive layer on a surface of the insulating substrate through which the tip of the conductive pillar has penetrated; Forming a first reinforcement pattern and a first circuit pattern on the first conductor layer; forming a second reinforcement pattern and a second circuit pattern on the second conductor layer; Curing the insulating substrate. A method for manufacturing a printed wiring board, comprising: A step of forming a substantially conical conductive pillar on the first conductive layer; a step of disposing an uncured first insulating substrate on the conductive pillar; Pressing a conductive layer and the first insulating substrate to penetrate the first insulating substrate through the conductive pillar; and a surface of the first insulating substrate through which the tip of the conductive pillar penetrated. Forming a second conductive layer thereon; forming a first reinforcing pattern and a first circuit pattern on the first conductive layer; and forming a second reinforcing layer on the second conductive layer. A step of forming a pattern and a second circuit pattern; a step of curing the insulating substrate to form a first core material; a substantially conical second conductive pillar on the second circuit pattern Forming an uncured second insulating substrate on the second conductive pillar Arranging; pressing the first core material and the second insulating substrate to allow the second conductive pillar to penetrate the second insulating substrate; Forming a third conductor layer on a surface of the conductive substrate through which the tip of the second conductive pillar penetrates; forming a reinforcing pattern and a third circuit pattern on the third conductor layer; Curing the second insulating substrate to form a multi-layer substrate. 4. The method of manufacturing a printed wiring board according to claim 1, wherein
Wherein the reinforcing pattern is formed around the first circuit pattern. 5. An insulating substrate, a first circuit pattern formed on a first surface of the insulating substrate, and a second circuit pattern formed on a second surface of the insulating substrate. A second circuit pattern in which a difference between an occupied area of the second surface and an occupied area of the first circuit pattern on the first surface is 0 to 5%. Printed wiring board. 6. An occupation of at least two laminated insulating substrates, and circuit patterns disposed on both surfaces of each of the insulating substrates, the circuit patterns facing each other via each of the insulating substrates. A printed wiring board, wherein the difference in the area is 0 to 5%.