JPH1131882A - Multilayered interconnection board and method for manufacturing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered interconnection board and its manufacturing method, wherein high-density wiring and high-density mounting are possible while maintaining reliable electrical connection. SOLUTION: In a multilayered interconnection board, interconnection patterns 9a, 9b, 9c, and 9d layers are electrically connected with a conductive bump 6 which penetrates an interlayered insulator 7a in the thickness direction, and a plated conductor layer 8 provided on an inside wall surface of a hole penetrating the inter-layer insulator in the thickness direction. Here, the inside of a through-hole where the plated conductor layer 8 is provided is filled with an insulator 10, and the electrical joint of the conductive bump 6 to the plated conductor layer 8 is established via a conductor layer 11 which is allocated on a filled surface of the insulator 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multilayer wiring board and a method for manufacturing the same.

[0002]

2. Description of the Related Art As means for reducing the size of circuit devices, multilayer printed wiring boards having a structure in which insulator layers and wiring pattern layers are alternately laminated are widely used. In this type of multilayer wiring board, in order to respond to demands for higher density and higher functionality of circuits, multilayer wiring pattern layers,
The connection between the wiring pattern layers is made.

FIG. 3 is a cross-sectional view showing an example of a configuration of a main part of a multilayer wiring board having a connecting portion for connecting between wiring pattern layers. In FIG. 3, 1a and 1b are outer layer wiring patterns, and 1c and 1d.
Is the inner layer wiring pattern, and 2 is the wiring pattern 1a, 1c, 1
Interlayer insulator layers 3a and 3b for insulating between d and 1b are connecting portions for electrically connecting the wiring patterns 1a, 1c, 1d and 1b. Here, the interlayer insulating layer 2 is an insulating resin layer such as a resin alone, a resin composition containing a filler, or a material obtained by attaching and containing a resin to a base material such as cloth.

[0004] Such a multilayer wiring board is generally manufactured by the following steps.

FIGS. 4A to 4C schematically show an embodiment of the process. First, as shown in cross section in FIG. 4A, for example, a double-sided copper foil-clad laminate (core substrate) is used. 4) After making a hole in 4, the entire surface including the inner wall surface of the formed hole 3a 'is subjected to chemical plating and further thickened by electroplating.
The reliability is improved by increasing the thickness of the metal layer (conductor layer) 3a on the inner wall surface of a '.

Next, the plating layers and the copper foil on both sides are subjected to, for example, photo-etching to perform required patterning 1c and 1d, and then, as shown in a sectional view in FIG. Then, copper foils 6a and 6b are laminated and arranged via an insulating resin sheet (for example, a prepreg resin sheet) 5, and integrated under pressure.

Then, as shown in cross section in FIG.
After drilling with the copper foils 6a and 6b integrated, chemical plating is applied to the entire surface including the inner wall surface of the formed hole 3b ', and further thickened by electroplating, and the inner wall surface of the hole 3b' is Increase the reliability by increasing the thickness of the metal layer (conductor layer) 3b.

Next, the formed plating layer and copper foil
6a and 6b are subjected to, for example, a photo-etching process to perform required patterning 1a and 1b. Thus, the wiring patterns 1a, 1
The electrical connection between b, 1c, 1d and the patterning of the copper foils 6a, 6b are performed, and the connection portions 3a, 3b for connecting the wiring patterns 1a, 1b, 1c, 1d as shown in FIG. We manufacture multilayer wiring boards with

On the other hand, in order to simplify the electrical connection process between the wiring patterns 1a, 1b, 1c, 1d involving the plating process, for example, the tip of a projecting conductor (conductive bump) made of a conductive paste is used. A method has been proposed in which an insulating resin layer interposed as an interlayer insulator 5 is penetrated in the thickness direction, and an electrical connection is made by contacting or pressing against an opposing wiring pattern surface.

[0010]

However, in the case of the multilayer wiring board having the above-mentioned structure, wiring patterning cannot be performed in the perforated hole area for forming the connection portions 3a and 3b, and the surface mounting of the electronic component must be performed. Can not. That is, in the via connection portion 3a and the through-hole connection portion 3b, since the wiring cannot be patterned, there is a problem that the design / specification of the wiring and the wiring density are restricted. In addition, through-hole connections
In 3b, mounting and mounting of electronic components are restricted, so that mounting density cannot be improved.

The via connection portion 3a and the through-hole connection portion
The problems caused by 3b are that high-density wiring or compaction of multilayer wiring boards, or high-density mounting circuits or
It becomes an obstacle such as shortening. In other words, in recent years, it has been desired to solve, solve, or improve this problem in order to respond to the demand for more compact circuit devices.

On the other hand, the leading ends of the protruding conductors (conductive bumps) penetrate through the interposed insulating resin layer and contact or press contact with the opposing wiring pattern surfaces to form the wiring patterns 1a, 1b, 1c. , 1d has a simple process, and can improve the wiring density and the mounting density. However, when higher reliability is required, there is a case where the reliability may be concerned in the connection configuration between the inner layer wiring patterns.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a multilayer wiring board capable of high-density wiring and high-density mounting and having high reliability of electrical connection, and a method of manufacturing the same. And

[0014]

According to a first aspect of the present invention, there is provided a conductive bump for penetrating an interlayer insulator in a thickness direction, and plating provided on an inner wall surface of a hole penetrating the interlayer insulator in a thickness direction. A multilayer wiring board having a configuration in which wiring layers are electrically connected by a conductive layer, wherein the inside of the through hole provided with the plated conductive layer is filled with an insulator, and The multilayer wiring board is characterized in that the electrical connection by the conductive bumps is performed via a conductive layer disposed on the filling surface of the insulator.

A second aspect of the present invention provides a step of forming a through hole in a thickness direction at a predetermined position of a core wiring board, forming an inner wall surface of the through hole as a plated conductor layer to form a through hole connection portion, Filling the inside of the through-hole with an insulator, forming a core wiring board by arranging a conductor layer that is conductive to the through-hole connection portion on at least one of the filled insulator surfaces, A step of positioning and arranging a conductive foil having conductive bumps for interlayer connection provided on one main surface thereof via an insulating sheet on a wiring board surface to form a laminate; A step of forming a conductive foil-clad laminate in which the tip of the conductive bump penetrating the sheet is in contact with and electrically connected to the conductive layer conducting to the through-hole connecting portion; and wiring patterning of the conductive foil And the step of A method for manufacturing a multilayer wiring board according to claim.

In the present invention, the core wiring board may be, for example, a single-sided wiring board, a double-sided wiring board, or a multilayer of three or more layers formed by a combination thereof, depending on the multilayer wiring board to be processed. Drilling of the through-hole forming a part of the connection portion is performed by, for example, drilling. The conductor layering of the inner wall surface of the through hole is performed by using a combination of general electroless plating and electroplating. Further, as an insulator that fills the through hole with the inner wall surface being a conductor layer, for example, An epoxy resin, a phenol resin, or a composition in which an inorganic filler is blended with these resins is exemplified. In general, it is desirable to fill the through holes with an insulator made of the same material as the insulator constituting the core wiring board.

The conductor layer (eg, foil) includes, for example, an electrolytic copper foil or an aluminum foil having a thickness of about 18 to 35 μm. It is appropriately selected depending on the size and the like. The formation of the conductive bumps (conductive protrusions) on one main surface of the conductive foil is performed by, for example, using a metal mask, screen printing a conductive resin paste and drying after printing as appropriate to obtain a predetermined size ( (Bottom diameter, height).

The conductive resin paste is prepared by mixing a conductive powder such as silver, gold, copper and solder powder, an alloy powder or a composite (mixed) metal powder thereof, and a resin binder component. Pastes. Examples of the resin binder component generally include, for example, thermoplastic resins such as polycarbonate resins, polysulfone resins, polyester resins, and phenoxy resins, and thermosetting resins such as phenol resins, polyimide resins, and epoxy resins. In addition, acrylic acid esters such as methyl methacrylate, diethyl methyl methacrylate, trimethylolpropane triacrylate, diethylene glycol diethyl acrylate, methyl acrylate, ethyl acrylate, diethylene glycol ethoxylate acrylate, acrylate of ε-caprolactone-modified dipentaerythritol, An ultraviolet curable resin such as a methacrylic acid ester or an electron beam irradiation curable resin may be used.

Further, examples of the insulating sheet disposed on the surface of the core wiring board include a thermoplastic resin film (sheet) and a thermosetting resin sheet.
About 100 μm is preferable. Here, examples of the thermoplastic resin sheet include sheets such as a polycarbonate resin, a polysulfone resin, a thermoplastic polyimide resin, a tetrafluoroethylene resin, a hexafluoropropylene resin, and a polyetheretherketone resin. The thermosetting resin (prepreg) sheet kept in a state before curing includes epoxy resin, bismaleimide triazine resin, polyimide resin, phenol resin, polyester resin, melamine resin, or butadiene rubber, butyl rubber, natural rubber, neoprene Examples include sheets of raw rubber such as rubber and silicone rubber. These synthetic resins may be used alone or may contain an insulating inorganic or organic filler, and may further contain a glass cloth or mat,
A sheet formed by combining with a reinforcing material such as an organic synthetic fiber cloth, a mat, or paper may be used.

According to the first aspect of the invention, the electrical connection between the wiring patterns is performed by using the conductive bumps and the plated conductor layer provided on the inner wall surface of the through hole, and the inside of the through hole is filled with an insulator. At the same time, the electrical bonding of the conductive bumps to the plated conductive layer is performed via the conductive layer disposed on the filling insulator surface. That is, since the through-hole type interlayer connection portion is filled with the insulator, the degree of freedom in designing the multilayer wiring pattern can be easily secured, and the effective mounting area can be increased.

According to the second aspect of the present invention, a multi-layer wiring board having a high-density wiring having a multi-layer wiring pattern having a high degree of freedom in design and having an effective area as a mounting area substantially enlarged, A multilayer wiring board can be provided with high yield.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIGS.

FIG. 1 is a sectional view showing the structure of a main part of a multilayer wiring board according to a first embodiment of the present invention. In FIG. 1, reference numeral 6 denotes a conductive bump penetrating the interlayer insulator 7a in the thickness direction, and reference numeral 8 denotes a plated conductor layer provided on an inner wall surface of a hole penetrating the interlayer insulator 7b in the thickness direction. In other words, this multilayer wiring board has outer wiring patterns 9a and 9b and inner wiring patterns 9c and 9c.
9d is electrically connected by the conductive bump 6,
A configuration is adopted in which some inner layer wiring patterns 9c and 9d are electrically connected to each other by a plated conductor layer 8 provided on the inner wall surface of the through hole.

More specifically, the structure of the multilayer wiring board will be described in more detail. A through-hole connecting portion is provided by a plated conductor layer 8 on the inner wall surface of a hole penetrating in the thickness direction between the wiring patterns 9c and 9d on both surfaces. After that, a double-sided wiring board having a conductor layer (for example, a plating layer) 11 which is electrically connected to the wiring patterns 9c and 9d while filling the inside of the through hole with an insulator 10 is used as a core wiring board 12. Has been adopted. Then, on both sides of the double-sided wiring board (core substrate) 12, outer layer wiring patterns 9a and 9b having conductive bumps 6 as interlayer connection parts are arranged.

In this configuration example, the wiring patterns 9a, 9b, 9
The connections between c and 9d are made at three places between the wiring patterns 9a and 9c, between the wiring patterns 9b and 9d, and between the wiring patterns 9a, 9b, 9c and 9d. Since there is no wiring pattern forming area and the mounting surface area, a form that is effectively used as a whole is adopted.

Next, an example of a method for manufacturing a multilayer wiring board having the above-described structure will be described.

First, a glass epoxy resin-based core wiring board 12 having a thickness of about 0.6 mm, an electrolytic copper foil having a thickness of 18 μm, and a diameter of 0.3 mm
A 0.3mm thick metal screen plate, a silver powder-phenolic resin-based conductive paste, and a glass epoxy resin-based prepreg (uncured) approximately 60μm thick, each of which is made by drilling holes at predetermined positions I do.

Next, a through hole having a diameter of about 0.3 mm is formed in a predetermined position (location) of the core substrate 12 by drilling, and the inner wall surface of the formed through hole is formed by electroless plating and electroplating. The conductor layer 8 forming the connection part is formed. Thereafter, an epoxy resin-based composition is provided in the through hole.
After filling with 10 and drying and curing, the conductive layer 11 is selectively formed on the filling surface of the resin 10 and the connecting surfaces of the inner wiring patterns 9c and 9d by, for example, electroplating.
Arrange (formation of core wiring board).

On the other hand, a metal screen plate is positioned and arranged on one main surface of the electrolytic copper foil, and
For example, a silver powder-phenol resin-based conductive paste is printed at a position facing the interlayer connection surface of the substrate. The printed conductive paste is dried at 165 ° C for 15 minutes, and then printed at the same position using the same metal screen plate.
After the drying process is repeated three times, a heating effect process is performed to provide conical conductive bumps 6 (bottom diameter 0.3 mm, height 0.25 mm).

Then, a conductive bump 6 for interlayer connection is provided on one main surface of the core wiring board via an insulating sheet (for example, a prepreg made of glass epoxy resin) 7a forming an interlayer insulating sheet. The body layer (electrolytic copper foil) is positioned and arranged to form a laminate. That is, the laminate was set on a heating die press via a contact plate, and heated at 175 ° C. and 40 kg /
Press for 1 hour at a pressure of about ² cm
The epoxy resin-based prepreg is hardened, and the tip of each conductive bump 6 penetrating the glass-epoxy resin-based prepreg is brought into contact with the connected portion (conductor layer) 11 of the core wiring board 12 facing each other. By making connection, an electrolytic copper foil on both surfaces and inner wiring patterns 9c and 9d are electrically connected to produce a copper foil-clad laminate.

Thereafter, a required etching resist pattern is printed on the copper foil surface of the outer layer of the copper foil-clad laminate by a screen printing method, and unnecessary copper foil is removed by etching using an aqueous solution of diiron chloride as an etchant. By removing the etching resist, a multilayer wiring board having the configuration shown in FIG. 1 is obtained.

In the multilayer wiring board manufactured as described above, the connection resistance of the wiring pattern layer is, for example, 2.1 Ω, and this value takes into account the copper foil pattern resistance (1 mΩ of copper foil pattern resistance per bump). Then, the average of the through-hole connection resistance was 1 mΩ, and both the via connection resistance and the copper foil pattern resistance had little variation.

FIG. 2 is a sectional view showing the structure of a main part of a multilayer wiring board according to a second embodiment. In the case of this configuration example, the connection between the wiring patterns 9a, 9b, 9c, 9d is basically the same as the configuration shown in FIG. Between, wiring pattern 9
It is performed at three places between c and 9d, but the wiring patterns 9c and 9d
Only the connection portion (via connection) by the plated conductor layer 8 is formed between d. In this configuration example, since there is no connection portion extending over four layers of the wiring patterns 9a, 9b, 9c, and 9d, the arrangement of the conductor layer 11 is omitted. However, since there is no space in the wiring board, a configuration is employed in which the wiring pattern forming region and the mounting surface region are effectively used as a whole.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the interlayer insulator layer
Instead of the glass-epoxy resin prepreg, a thermoplastic resin may be used, and the conductive protrusions may be formed of a conductive composition other than silver powder-phenol resin. Further, the core substrate is not limited to the double-sided type, but may be a multilayer type in which the layers are connected by conductive bumps or the like.

[0035]

According to the first aspect of the present invention, the electrical connection between the wiring patterns is made by using the conductive bumps and the plated conductor layer provided on the inner wall surface of the through hole, while the inside of the through hole is made of an insulator. Thus, a multilayer wiring board capable of high-density wiring or high-density mounting is provided.

According to the second aspect of the present invention, a light, thin, short, and multi-layered structure which has a high degree of freedom in designing a wiring pattern, has a substantially expanded mounting area, and is suitable for a highly reliable high-density mounting circuit, etc. Wiring boards are provided with good yield.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a main part of a multilayer wiring board according to a first embodiment.

FIG. 2 is a sectional view showing a configuration of a main part of a multilayer wiring board according to a second embodiment.

FIG. 3 is a cross-sectional view showing an example of a configuration of a main part of a conventional multilayer wiring board.

FIG. 4 schematically shows an embodiment of a conventional method for manufacturing a multilayer wiring board, in which (a) is a cross-sectional view showing a state in which a through-hole connecting portion is provided in a double-sided copper foil-clad laminate, and (b). FIG. 2 is a cross-sectional view showing a state in which wiring patterning is performed on both sides, and FIG. 2C is a cross-sectional view showing a state in which a through hole for forming a through-hole connection portion is provided in a multilayered double-sided copper foil-clad laminate.

[Explanation of symbols]

 6 Conductive bumps (interlayer connection parts) 7a, 7b ... Interlayer insulator 8 ... Plating conductor layers (interlayer connection parts) 9a, 9b, 9c, 9d ... Wiring pattern 10 ... Filled insulator (plating) Filling in the through hole for forming the conductor layer) 11 Conductor layer 12 Core wiring board

Claims (2)

[Claims] An electric connection between wiring pattern layers is provided by a conductive bump penetrating an interlayer insulator in a thickness direction and a plated conductor layer provided on an inner wall surface of a hole penetrating the interlayer insulator in a thickness direction. A multi-layer wiring board having a configuration in which the through hole provided with the plated conductor layer is filled with an insulator, and an electrical connection to the plated conductor layer by a conductive bump is made of an insulator. A multi-layer wiring board, wherein the multi-layer wiring board is formed through a conductor layer disposed on a filling surface of the multi-layer wiring board. 2. A step of providing a hole penetrating in a thickness direction at a predetermined position of the core substrate, forming an inner wall surface thereof as a plated conductor layer to form a through-hole connection portion, and forming a through-hole connection portion provided with the through-hole connection portion. Filling with an insulator, forming a core wiring board by arranging a conductive layer conducting to the through-hole connection portion on at least one of the filled insulator faces, and insulating the core wiring board face from the insulating layer. A step of positioning and arranging a conductive foil having conductive bumps for interlayer connection provided on one main surface via a sheet to form a laminate, and a step of pressing and integrating the laminate to penetrate an insulating sheet. Forming a conductive foil-clad laminate in which the tip of the conductive bump is in contact with and electrically connected to the conductive layer that is electrically connected to the through-hole connecting portion; and a step of wiring patterning the conductive foil. Characterized by many A method for manufacturing a wiring board.