JPH09260855A - Multilayered wiring board manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-density and high-reliability multilayered wiring board manufacturing method whereby the prepared hole forming step is omitted and poor conduction and poor insulation caused by cutting pieces of an iorg. filler contained in a base to be an insulation layer will not occur. SOLUTION: A Cu foil 3 is hot press-formed so that an insulation layer 5 exists between a core board 1 having a conductor circuit 10 and fail 3 to form a multilayered structure, vias 4 for wiring between the conductor circuit 10 and foil 3 are formed by a laser beam machine to form a multilayered wiring board. The hot press-forming is made with an insulation layer resin 8 inserted between the board 1 and foil 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a high-density multilayer wiring board having via holes.

[0002]

2. Description of the Related Art In recent years, in response to the miniaturization of wiring in printed wiring boards, the increase in the number of layers, and the miniaturization of interlayer connection holes, it has been possible to manufacture a high-density multilayer wiring board by conducting vias between layers. It is being appreciated.

As a method of manufacturing a multilayer wiring board having such a via hole, for example, Japanese Patent Laid-Open No. 61-1336 is used.
There is one described in Japanese Patent Publication No. 96. The steps of the method for manufacturing the multilayer wiring board are shown in FIG.

That is, as shown in (A) of this figure, a pilot hole 21 is formed in a base material 20 to be the insulating layer 5 by machining such as a drill, and as shown in (B) to (C), The base material 20 is heated and pressure-molded via the copper foil 3 and the core base material 1 to form a multilayer, and the pilot hole 21 is filled with a resin and cured at the time of the heat-pressure molding. Then, as shown in (D), an interlayer connection hole 22 smaller than the diameter of the pilot hole 21 is formed by laser processing to the depth of the conductor circuit 10 of the core base material 1. further,
As shown in (E), a conductor pattern by plating and circuit pattern formation such as etching are formed in the interlayer connection hole 22 to obtain a multilayer wiring board in which the via hole 4 is formed.

Interlayer connection hole formed by laser processing as described above
22 is extremely easy to form up to the depth of the conductor circuit 10 of the core base material 1 as compared with machining, and is suitable for manufacturing a high-density multilayer wiring board. Is.

[0006]

However, in the above-mentioned conventional example, the step of forming the pilot hole 21 by machining is required, and the step becomes long and the insulating layer 5 is formed.
Since shavings of the inorganic filler contained in the base material 20 that becomes the base material are generated, there is a problem in that conduction failure and insulation failure of the multilayer wiring board are likely to occur.

In order to eliminate such a defect, if the underhole processing is omitted, the inorganic filler contained in the base material 1 which becomes the insulating layer 5 has a shape protruding to the inner wall of the interlayer connection hole, which is practically used. It is not used, and the same problem cannot be solved by laser processing the prepared hole.

As a countermeasure against the above-mentioned drawback, it is conceivable to form the insulating layer 5 by using a resin containing no inorganic filler, such as glass cloth, as a base material. It is difficult to secure.

Alternatively, the base material 20 to be the insulating layer 5
A method is conceivable in which the inorganic filler such as glass cloth before forming is formed with the pilot holes 21 in advance by laser processing and is then impregnated with resin to form the base material 20 to be the insulating layer 5. However, this method has a drawback that the positional accuracy of the pilot hole 21 tends to be insufficient. Further, even if the base material 20 to be the insulating layer 5 is a prepreg impregnated with an uncured resin,
There are almost similar drawbacks.

The present invention has been made to solve the above problems, and an object thereof is to save the step of forming a pilot hole and to improve the inorganic filler contained in the base material to be an insulating layer. It is an object of the present invention to provide a method for manufacturing a multilayer wiring board having high density and high reliability, which does not cause defective conduction or defective insulation due to scraps.

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 heats and pressurizes a copper foil 3 so as to have an insulating layer 5 between the core substrate 1 having a conductor circuit 10. In the method for manufacturing a multilayer wiring board, the via hole 4 is formed by laser processing, the via hole 4 being formed into multiple layers and connecting the conductor circuit 10 and the copper foil 3 to each other. The insulating layer resin 8 that does not contain an inorganic filler is interposed therebetween to perform heat and pressure molding.

According to such a method for manufacturing a multilayer wiring board, since the insulating layer 5 is formed of the insulating layer resin 8 which does not contain an inorganic filler, when the via hole 4 is processed by laser processing, an inorganic filler or the like is not formed. The inner wall of the via hole 4 is formed smoothly without generating shavings and without causing the inorganic filler to project to the inner wall of the hole.

According to a second aspect of the present invention, in the first aspect of the invention, the insulating layer resin 8 is applied to the core base material 1 and cured, and the cured insulating layer resin 8 is further overlaid. The insulating layer resin 8 is applied and heat-pressed.

According to such a method for manufacturing a multilayer wiring board, the thickness of the insulating layer 5 is substantially ensured by the insulating layer resin 8 that has been cured previously, and the copper foil is further applied by the insulating layer resin 8 that is applied in layers. Adhesion with 3 is surely performed.

According to a third aspect of the present invention, in the first aspect of the invention, after the insulating layer resin 8 is applied to the core base material 1, a spacer 9 is placed on the core base material 1 and heated. It is characterized by being pressure molded.

According to such a method for manufacturing a multilayer wiring board, the spacer 9 suppresses the outflow of the insulating layer resin 8 and secures the thickness of the insulating layer 5. Further, since the insulating layer resin 8 is applied first, this applying operation is easily performed.

According to a fourth aspect of the present invention, in the first aspect of the invention, the spacer 9 is placed on the core base material 1, the insulating layer resin 8 is applied to the core base material 1 and heated. It is characterized by being pressure molded.

According to such a method for manufacturing a multilayer wiring board, the spacer 9 suppresses the outflow of the insulating layer resin 8 and secures the thickness of the insulating layer 5. In addition, first the spacer 9
Since it is mounted, it can be easily mounted at an accurate position.

According to a fifth aspect of the present invention, the copper foil 3 is heat-pressed and formed into a multi-layer with the core base material 1 having the conductor circuit 10 via a prepreg 6 having an inorganic filler, and the conductor circuit is formed. In a method of manufacturing a multilayer wiring board for forming a via hole 4 for interlayer connection between the copper foil 3 and the copper foil 3, an interlayer conduction connection pin 7 is provided between the conductor circuit 10 of the core base material 1 and the prepreg 6. The feature is that they are arranged and heated and pressed.

According to such a method for manufacturing a multilayer wiring board, the via holes 4 are formed by the connection pins 7 for interlayer conduction, and the drilling of the via holes 4 is omitted.

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

The first embodiment will be described below with reference to FIG. This drawing is an explanatory view showing in sequence the manufacturing steps of the multilayer wiring board in this embodiment.

In this embodiment, a copper foil 3 is heat-pressed and molded so as to have an insulating layer 5 between a core substrate 1 having a conductor circuit 10 and a multilayer structure. Foil 3
When forming the via hole 4 for interlayer connection with the core material 1 and the copper foil 3 by the laser processing, the insulating layer resin 8 containing no inorganic filler is interposed between the core material 1 and the copper foil 3 to perform heat and pressure molding. Is characterized by.

As the core base material 1, a base material such as a film or a plate having a conductor circuit formed on the surface of a base material is used. As such a core base material 1, an epoxy resin or a polyimide resin is used. As a typical example, a glass substrate laminated plate using a heat resistant resin such as the above can be exemplified. Then, the insulating layer resin 8 is applied to the surface of the core base material 1 by curtain coating or the like to intervene the copper base material 1 and the copper foil 3 is further laminated by heat and pressure to form a multilayer structure. The insulating layer resin 8 may be the same as the base resin used for the core substrate 1.

The manufacturing process will be described below with reference to the drawings. First, the insulating layer resin 8 is applied to the core base material 1 in the state as shown in FIG. As the core base material 1,
A base material for a heat-resistant printed wiring board having copper foils on both sides is used, and conductor circuits 10 and 10a are pattern-formed on both sides. In this case, the lower conductor circuit 10a is left on substantially the entire surface. Then, the insulating layer resin 8 is heated to some extent to be cured, and then the insulating layer resin 8 is further applied as shown in FIG. Then, after further curing to some extent, the copper foils 3 are stacked and heat-pressed as shown in (C) to obtain a multilayer substrate. The degree of curing of the insulating layer resin 8 at this time is set so that the insulating layer resin 8 applied earlier does not flow anymore and the insulating layer resin 8 afterwards flows to some extent. It has an appropriate thickness and adheres well to the copper foil 3.

Further, as shown in (D), the copper foil 5 is subjected to circuit forming work such as exposure, development and etching to form a circuit pattern 11, and as shown in (E), the via hole 4 is formed by laser processing. The hole 12 is formed. In this case, since the circuit pattern 11 is formed by substantially removing the via hole 4, the laser processing is facilitated. Further, as shown in (F), copper is plated in the hole 12 to electrically connect the circuit pattern 11 on the surface and the conductor circuit 10 of the core base material 1 to complete the via hole 4. I'm getting a board.

According to such a method for manufacturing a multilayer wiring board, since the insulating layer 5 is formed of the insulating layer resin 8 which does not contain an inorganic filler, an inorganic filler or the like is processed at the time of processing the hole 12 of the via hole 4 by laser processing. The inner wall of the via hole 4 is formed smoothly without generating any shavings, and without the inorganic filler protruding to the inner wall of the hole 12.

Therefore, it is not necessary to perform the conventional pilot hole processing, and the conduction failure and the insulation failure caused by the shavings of the inorganic filler are eliminated. Moreover, the laser processing prevents the inorganic filler from protruding to the inner wall of the hole 12, and the inner wall of the via hole 4 is formed smoothly, so that the conduction reliability is further increased and
Since the laser processing facilitates the processing of holes having a small diameter, it is possible to manufacture a high-density multilayer wiring board.

The above laser processing can be performed by a method such as plasma or chemical etching. Drilling by such a method, unlike mechanical processing such as drilling, it is possible to eliminate the problem that the above-mentioned inorganic filler protrudes on the inner wall of the hole 12 and a decrease in conduction reliability due to shavings, The via hole 4 having a small diameter and high reliability can be formed.

A second embodiment will be described below with reference to FIGS. FIG. 2 is an explanatory view sequentially showing the manufacturing process of the multilayer wiring board in this embodiment, and FIG. 3 is a perspective view showing the spacer 9 used in this manufacturing process.

As shown in FIG. 2, in this embodiment,
After applying the insulating layer resin 8 to the core base material 1, the spacers 9 are placed on the core base material 1 and heat-pressed.

As shown in FIG. 3, this spacer 9 is formed in a shape in which a window is opened by hollowing out a portion where the via hole 4 is not formed, and the insulating layer resin 8 flows out by heat and pressure molding. An insulating material having a function of preventing the above is used. As a specific example, a prepreg made of the same resin as the core substrate 1 can be used.

The manufacturing process will be described below with reference to the drawings. First, in the state as shown in (A), the insulating layer resin 8 is applied to the core base material 1, the spacer 9 is placed on the core base material 1, and the copper foil 3 is further stacked. Then, as shown in (B), heat and pressure molding is performed to obtain a multilayer substrate. Further, as shown in (C), a circuit forming operation such as exposure, development, and etching is performed on the copper foil 5 to form a circuit pattern 11, and as shown in (D), a via hole 4 to be a via hole 4 by laser processing. 12 is formed, and as shown in (E), the hole 12 is copper-plated to connect the circuit pattern 11 on the surface and the conductor circuit 10 of the core substrate 1 to complete the via hole 4. You have a multilayer wiring board.

According to such a method for manufacturing a multilayer wiring board, even if the insulating layer resin 8 has an adhesive force with respect to the copper foil 3 and is easily fluidized at the time of heat and pressure molding, the spacer 9 allows the insulating layer resin 8 to flow. The thickness of the insulating layer 5 is secured. Further, since the insulating layer resin 8 is applied first, this applying operation is easily performed.

The third embodiment will be described below with reference to FIG. This drawing is an explanatory view showing in sequence the manufacturing steps of the multilayer wiring board in this embodiment.

In this embodiment, unlike the second embodiment, as shown in (A) to (B), after the spacer 9 is placed on the core base material 1, the core base material 1 is insulated. Layer resin 8
Is applied and heat-pressed and molded. The subsequent steps can be performed in exactly the same way as in FIG.

Therefore, in the method of this embodiment,
Similar to the second embodiment, the thickness of the insulating layer 5 is ensured by the spacer 9. However, since the spacer 9 is placed first, the spacer 9 can be easily placed at the correct position. There is an advantage that can be.

The fourth embodiment will be described below with reference to FIG. This drawing is an explanatory view showing in sequence the manufacturing steps of the multilayer wiring board in this embodiment.

As shown in this figure, in this embodiment, a copper foil 3 is heat-press molded with a core base material 1 having a conductor circuit 10 via a prepreg 6 having an inorganic filler to form a multilayer. And forming a via hole 4 for connecting the conductor circuit 10 and the copper foil 3 to each other between the conductor circuit 10 and the prepreg 6 of the core base material 1. It is characterized in that they are arranged and heated and pressed.

Therefore, since the via hole 4 is formed by the connection pin 7 for interlayer conduction, the drilling process and the plating process of the via hole 4 are omitted. Further, since the prepreg 6 is used in order to form the insulating layer 5 without using the insulating layer resin 8, the application work of the insulating layer resin 8 is omitted, and the multilayer wiring board having the via holes 4 in a simple process. Can be manufactured.

The above steps will be described below with reference to the drawings. That is, as shown in FIG.
An interlayer conductive connection pin 7 is adhered and fixed on the conductor circuit 10 forming the via hole 4 in FIG.
The prepreg 6 and the copper foil 3 are superposed on the core substrate 1 and heat-pressed. (B) shows the thus obtained multilayer substrate, which is irradiated with a beam 13 such as a laser or an electron beam to weld the copper foil 3 and the connection pin 7 for interlayer conduction. . Further, as shown in (C), a circuit pattern forming operation such as exposure, development, and etching is performed on the copper foil 5 to form a circuit pattern 11, and the circuit pattern 11 and the conductor circuit 10 of the core base material 1 are formed. A multilayer wiring board connected by the connection pins 7 for interlayer conduction is obtained.

That is, by the inter-layer conduction connecting pin 7,
Since the via hole 4 is formed, the via hole with high connection reliability can be easily formed by a simple process that can omit the drilling process of the via hole 4.

[0043]

According to the first aspect of the present invention, since the insulating layer does not contain the inorganic filler, shavings of the inorganic filler or the like are not generated when the via hole is processed by the laser processing. Therefore, it is possible to easily manufacture a multilayer wiring board which does not require conventional pilot hole processing and does not cause conduction failure and insulation failure caused by such shavings of the inorganic filler.

In addition, since the inorganic filler does not project to the inner wall of the hole by the laser processing and the inner wall of the via hole is formed smoothly, the conduction reliability is further improved, and the laser processing makes the hole of a minute diameter small. Since the processing is facilitated, a high-density multilayer wiring board can be manufactured.

According to the second aspect of the invention, the thickness of the insulating layer is substantially ensured by the insulating layer resin which has been previously cured, and the insulating layer resin applied in layers ensures the adhesion to the copper foil. . That is, it is possible to form an insulating layer having no inorganic filler and having the above effect of the invention of claim 1 so as to have a proper thickness and to be well adhered to the copper foil.

According to the third aspect of the invention, the thickness of the insulating layer is ensured by the spacer, and the insulating layer resin is applied prior to placing the spacer. Therefore, this applying operation can be easily performed. .

According to the fourth aspect of the present invention, the thickness of the insulating layer is ensured by the spacer, and the spacer is placed prior to the application of the insulating layer resin. Therefore, the spacer can be easily placed at a correct position. be able to.

According to the fifth aspect of the present invention, since the via hole is formed by the connection pin for interlayer conduction, it is possible to omit the drilling process of the via hole and easily form the via hole with high connection reliability. .

[Brief description of drawings]

FIG. 1 is an explanatory view sequentially showing a manufacturing process of a multilayer wiring board according to a first embodiment of the present invention.

FIG. 2 is an explanatory view sequentially showing a manufacturing process of a multilayer wiring board according to a second embodiment of the present invention.

FIG. 3 is a perspective view showing a spacer used in the above manufacturing process.

FIG. 4 is an explanatory diagram sequentially showing a manufacturing process of a multilayer wiring board according to a third embodiment of the present invention.

FIG. 5 is an explanatory diagram sequentially showing a manufacturing process of a multilayer wiring board according to a fourth embodiment of the present invention.

FIG. 6 is an explanatory view sequentially showing a manufacturing process of a conventional multilayer wiring board.

[Explanation of symbols]

 1 core base material 2 insulating layer 3 copper foil 4 via hole 5 insulating layer 6 prepreg 7 connecting pin for interlayer conduction 8 insulating layer resin 9 spacer 10 conductor circuit 11 circuit pattern 12 hole 13 beam 20 base material 21 lower hole 22 interlayer connecting hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichiro Tanaka Inventor Kenichiro Tanaka 1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.

Claims (5)

[Claims] 1. A via hole for performing interlayer connection between the conductor circuit and the copper foil by thermocompressing a copper foil so as to have an insulating layer between the core substrate having the conductor circuit and the core substrate,
In the method for manufacturing a multilayer wiring board formed by irradiating with a laser, an insulating layer resin that does not contain an inorganic filler is interposed between the core base material and the copper foil, and heat and pressure molding is performed. Manufacturing method of multilayer wiring board. 2. The core layer is coated with the insulating layer resin and cured, and the cured insulating layer resin is further overlaid with the insulating layer resin and heat-pressed. The method for manufacturing a multilayer wiring board according to claim 1. 3. The method for manufacturing a multilayer wiring board according to claim 1, wherein after applying the insulating layer resin to the core base material, a spacer is placed on the core base material and heat-pressed. Method. 4. The multilayer wiring board according to claim 1, wherein after mounting the spacer on the core base material, the insulating layer resin is applied to the core base material and heat-pressed. Production method. 5. A copper foil is heat-press-molded between a core substrate having a conductor circuit and a prepreg containing an inorganic filler to form a multilayer, and interlayer connection between the conductor circuit and the copper foil is performed. In a method for manufacturing a multilayer wiring board in which a via hole is formed, an interlayer conduction connection pin is arranged between the conductor circuit of the core base material and the prepreg, and heat press molding is performed. Production method.