JP2000101232A - Printed wiring board and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a printed wiring board with high wiring density in which electric resistance is low, connection reliability is high, and a conductor layer generates no unevenness by arranging and laminating a prepreg between the surface side of a conductor circuit of a laminated circuit board and a core base and etching the conductor layer to form a circuit pattern. SOLUTION: This printed wiring board is manufactured by laminating a laminated circuit board 20 composed of resin layer and conductor layer in which a via hole 4 and a condcutor circuit 5 are formed, on a core base 7 in which a through hole, via hole and circuit pattern are formed on a substrate as a base, while the surface on which the conductor circuit 5 is formed is kept facing the core base 7 and prepregs 6 and 6' are in between and by forming a circuit pattern on the surfacial conductor layer. Thus, the reliability of the via hole 4 is high, and the conductor layer and circuit pattern formed on the via hole 4 generates no unevenness. Further, the conductor layer and circuit pattern can be used as a pad for mounting electronic parts, and its wiring density is high and the reliability for printed wiring board is high.

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 a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, various electronic components have been miniaturized with the miniaturization of electronic devices. Further miniaturization and reliability are required for printed wiring boards on which these electronic components are mounted. Further, not only miniaturization of a printed wiring board but also miniaturization of a wiring circuit are required. That is,
With the miniaturization and miniaturization of electronic components mounted on printed wiring boards, wiring circuits have been miniaturized, and the presence of through holes, via holes, etc. in lands to be mounted and fixed by soldering has reduced the amount of solder used for soldering. It has been an obstacle for control and so on. To solve these problems, as shown in FIG. 5, in order to form the outermost layer of the multilayer printed wiring board, a hole is formed, the hole is filled with a conductive filler 33, and a via hole is formed by plating. , Filling the holes with filler material 33)
It is proposed to form a circuit pattern including lands for component mounting on the via holes, or to form via holes and through holes at locations away from the lands and cover these holes with solder resist. Was.

[0003]

However, the conventional method has the problem that the electric resistance of the filler increases.
The problem of noise due to electrical connection by particulate matter, the problem that it is difficult to make the filled surface flat and unevenness occurs in the conductor layer, the problem that the wiring density is low because holes are provided in distant places, And so on. Accordingly, an object of the present invention is to provide a printed wiring board and a method of manufacturing the printed wiring board which have solved the problems such as low electric resistance, high reliability of electric connection, no irregularities in the conductor layer, and high wiring density.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a printed wiring board comprising a core substrate, a prepreg, and a laminated circuit board, and a method for manufacturing the same, comprising: a resin layer having conductive circuits and via holes formed on the same surface; A prepreg is arranged and laminated between the surface side of the conductor circuit of the laminated circuit board composed of the conductor layer and the core substrate, and a circuit pattern is formed by etching the conductor layer by a subtractive method.
It is a printed wiring board that is laminated using a laminated circuit board with highly reliable via holes and conductor circuits formed using ordinary technical methods, and component mounting pads and circuit patterns are formed on the outermost via holes. There is a problem that the component mounting pad on the via hole can be used as a soldering pad, and that the pad can be made small, so that the reliability of electric connection is high, the conductive layer does not have unevenness, and the wiring density is high. An object of the present invention is to provide a printed wiring board and a method of manufacturing the same.

Hereinafter, a printed wiring board according to the present invention and a method for manufacturing the same will be described in detail.

According to the printed wiring board and the method of manufacturing the same according to the present invention, a through hole, a via hole,
The resin layers 1 and 11 are provided on the core substrate 7 on which the circuit pattern is formed.
And via holes 4, 1 made of conductive layers 2, 12, 12 '.
4. Laminated circuit board 20, 2 on which conductor circuits 5, 15 are formed
1 is manufactured by laminating the prepregs 6 and 6 ′ with the surface on which the conductor circuit is formed on the core substrate side and forming a circuit pattern on the conductor layer on the surface.

The base substrate is a substrate composed of a conductor layer and a resin layer. Examples of the conductor layer include copper, aluminum, stainless steel, nickel, chromium, and the like. The resin layer includes epoxy, polyimide, polyester, phenol, and phenol. Glass fiber cloth impregnated with a resin such as bismaleimide / triazine, etc./glass fiber-free resin may be exemplified. The number of layers is not limited, and may be a single-sided, double-sided, or multi-layered one, preferably a single-sided copper-clad substrate, a double-sided copper-clad substrate, or a multilayered copper-clad substrate.

[0008] Through holes, via holes to the core substrate 7,
The method for forming the circuit pattern and the like is not particularly limited, and may be a method based on ordinary techniques.

The laminated circuit boards 20 and 21 are composed of resin layers 1 and 11 and conductor layers 2 and 12 having conductor circuits 5 and 15 and via holes 4 and 14 formed on the same surface.
Examples of the resin layer include a material obtained by impregnating a glass fiber cloth with a resin similar to that of the substrate described above, a material containing no glass fiber, and a resin having a thermosetting property and / or a photosetting property.
Examples of the conductor layer include the same examples as the above-described substrate. The method of forming the conductor circuit, the through hole, and the like is not particularly limited, but preferably, a fine via hole is formed by laser drilling.

[0010] The laminating method includes a core substrate 7, a prepreg 6,
When laminating 6 ′ and the laminated circuit boards 20 and 21, they are arranged and laminated via a prepreg such that the surface of the laminated circuit board on which the conductor circuits and via holes are formed faces the core substrate side. Other than the direction and arrangement of the lamination, there is no particular limitation, and a method according to a usual technique may be used.

The method for forming a circuit pattern on the conductor layer after lamination is not particularly limited, if desired, such as drilling for a through hole, drilling for a via hole, plating for electrical connection, etching of the conductor layer, and the like. The method may be a conventional technique.

Further, generally, a solder resist is applied to a portion other than a portion to be soldered by an ordinary technique.

In the printed wiring board manufactured as described above, the reliability of the via hole formed in the outermost layer is high, and the conductive layer / circuit pattern formed on the via hole is used for mounting, fixing, and fixing the electronic component. It can be used as a connection pad and has a high wiring density.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the printed wiring board according to the present invention and a method for manufacturing the same will be described below. The printed wiring board and the method for manufacturing the same according to the present invention are not limited to the following embodiments.

(Example 1) A copper-clad double-sided board in which a glass fiber cloth impregnated with a resin containing an epoxy resin as a main component and a copper foil having a thickness of about 18 µm was attached to both sides of an insulating material having a thickness of about 100 µm was used. Used and commonly used methods (drilling, smearing, copper plating, forming a circuit pattern by subtractive method using photoresist, blackening the copper surface of the circuit pattern, chemical reduction treatment, etc.) A core substrate 7 having a circuit pattern was formed.

A copper fiber comprising a resin layer 11 having a thickness of about 60 μm and a conductor layer (copper foil) 12, 12 ′ having a thickness of about 12 μm adhered to both sides of a glass fiber cloth impregnated with a resin mainly composed of epoxy resin. A window is opened in the copper foil 12 'on one side of the copper-clad double-sided substrate by an etching method using a laminated double-sided substrate (a photo-dry film is laminated at a desired position for forming a via hole, exposed to ultraviolet rays in a photomask pattern, and developed, The copper foil 12 ′ is etched and the dry film is peeled off.) A laser having a smaller diameter than the window (pulse width 200 μS, frequency 1) placed on a processing table of a carbon dioxide laser device
(2.5 Hz, 2.5 Hz, 6 shots) to vaporize and decompose the resin of the resin layer 11 in the window portion, melt the glass fiber, and form a hole where the copper foil 12 on the opposite side is exposed. The inner surface of the hole is smeared by a potassium method, and the copper foils 12 and 12 'on both surfaces are electrically connected to each other through the hole by a normal plating method (electroless copper plating, electrolytic copper plating). The conductive circuit 15 and the via hole 14 are formed on one side by an active method (lamination of a photo-dry film, exposure to ultraviolet rays with a photomask pattern, development, etching of the conductor layer 12 ', and stripping of the dry film).
Was formed. (FIG. 3 (b))

The prepregs 6, 6 'are provided on both sides of the core base material 7.
Are further disposed on both sides of the laminated circuit board.
Are arranged so that the surface on which the conductor circuit 15 and the via hole 14 are formed faces the core base material side (similar to FIG. 4), and are laminated using a vacuum chamber (heating 180 degrees for 120 minutes, pressure 25 kg). A substrate was formed.

A hole for a through hole is drilled in the laminated substrate using a drill, smearing is performed, copper plating is performed, and the outermost conductor layer is etched by a subtractive method to form a circuit pattern. Solder resist was applied to the positions to produce a six-layer printed wiring board.

The printed wiring board thus manufactured is
The reliability of the via hole was high, and highly reliable soldering was achieved using the conductor layer and circuit pattern formed on the via hole as mounting pads for electronic components.

Example 2 A copper-clad double-sided board in which a glass foil cloth impregnated with a resin containing an epoxy resin as a main component and a copper foil having a thickness of about 18 μm was adhered to both sides of an insulating material having a thickness of about 100 μm was used. Used and commonly used methods (drilling, smearing, copper plating, forming a circuit pattern by subtractive method using photoresist, blackening the copper surface of the circuit pattern, chemical reduction treatment, etc.) A core substrate 7 having a circuit pattern was formed.

A copper-clad single-sided board in which a resin layer 1 having a thickness of about 60 μm, in which a resin containing an epoxy resin as a main component is impregnated into a glass fiber cloth, is laminated on one side of a conductor layer (copper foil) 2 having a thickness of about 12 μm. The copper-clad single-sided substrate is placed on a processing table of a carbon dioxide gas laser apparatus, and a laser (pulse width 200 μS, frequency 100H) is applied from the resin layer side of the copper-clad single-sided substrate.
z, 2.5 mJ, 6 shots) to vaporize and decompose the resin at the desired position of the via hole in the resin layer 1 to melt the glass fiber to form a hole 3 (FIG. 2A), The inside of the hole is smeared by a potassium method, and a via hole 4 and a conductive circuit 5 electrically connected to the copper foil 2 by a usual additive method (forming a plating resist pattern and performing electroless plating) are connected to the copper foil 2. Formed a laminated circuit board 20 having the opposite surface. (FIG. 2 (b))

The prepregs 6, 6 'are provided on both sides of the core base material 7.
And the conductor circuits 5 of the laminated circuit boards 20, 20 '
The laminated circuit boards are further arranged on both sides such that the surface on which the via hole 4 is formed faces the core base material side (FIG. 4), and laminated using a vacuum chamber (heating at 180 ° C. for 120 minutes, Pressure 25 Kg) A laminated substrate was formed.

A hole for a through hole is formed in the laminated substrate using a drill, a smearing process is performed, copper plating is performed, a circuit pattern is formed by a subtractive method, a solder resist is applied to a desired position, and a through hole 8 is formed. A printed wiring board having six layers (FIG. 1, solder resist is not shown) was manufactured.

The printed wiring board thus manufactured is
The reliability of the via hole was high, and highly reliable soldering could be performed using the conductor layer / circuit pattern formed on the via hole as a mounting pad for electronic components.

[0025]

According to the printed wiring board of the present invention and the printed wiring board manufactured by the method for manufacturing the same, the reliability of the via hole is high, and the conductor layer / circuit pattern formed on the via hole has few irregularities. Since the conductor layer and the circuit pattern can be used as mounting pads for electronic components, the wiring density can be increased and the reliability as a printed wiring board is high.

[0026]

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a printed wiring board and a method of manufacturing the same according to the present invention.

FIG. 2 is a cross-sectional view showing one embodiment of a printed wiring board according to the present invention and a laminated circuit board of a method for manufacturing the printed wiring board, and FIG.
2 is a cross-sectional view in which a hole is formed in a resin layer, and FIG. 2B is a cross-sectional view in which a via hole and a conductive circuit are formed.

FIG. 3 is a cross-sectional view showing one embodiment of a printed wiring board according to the present invention and a laminated circuit board of a method for manufacturing the printed wiring board, and FIG.
FIG. 2 is a cross-sectional view in which a conductor layer is laminated on both surfaces of a resin layer, and FIG. 2B is a cross-sectional view in which a via hole and a conductor circuit are formed.

FIG. 4 is a cross-sectional view of a stacked arrangement showing one embodiment of a printed wiring board and a method of manufacturing the same according to the present invention.

FIG. 5 shows a conventional printed wiring board and a method of manufacturing the same.

[0027]

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 11 Resin layer 2, 12, 12 ', 32 Conductive layer 3 Hole 4, 14 Via hole 5, 15 Conductor circuit 6, 6' Prepreg 7 Core base material 8 Through hole 20, 20 ', 21 Laminated circuit board 33 Filler

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuharu Nagasaki 66-26, Serizawa-cho, Sukagawa-shi, Fukushima Prefecture (72) Inventor Shun-ichi Sakagami, Fukushima-shi, Fukushima-shi, Fukushima 15th F-term (reference) 5E346 AA43 DD32 EE09 FF07 FF13 GG15 GG22 GG28

Claims (1)

[Claims] 1. A printed wiring board comprising a core substrate, a prepreg and a laminated circuit board laminated, and a method for producing the same.
A prepreg is arranged and laminated between the surface side of the conductor circuit and the core substrate of a laminated circuit board comprising a resin layer and a conductor layer in which the conductor circuit and the via hole are formed on the same surface, and the conductor is formed by a subtractive method. A printed wiring board and a method of manufacturing the same, characterized in that a circuit pattern is formed by etching a layer.