JP2003347735A - Manufacturing method of multilayer wiring board - Google Patents

Abstract

A manufacturing method of a multilayer wiring board capable of forming a fine via and forming a dense wiring pattern is provided. SOLUTION: A step of forming a via hole 30 in which a wiring pattern 23 is exposed at the bottom of a required portion of an insulating adhesive layer 27 by laser processing, and a filling step of filling a solder paste in the via hole 30 to form a via 31. The second laminated unit 32 and the first laminated unit 25 are
Thermocompression bonding is performed such that the corresponding via 31 and the wiring pattern 24 are brought into contact with each other and are thermocompression bonded, and the via 31 made of solder paste is melted and connected to the corresponding wiring pattern 24 and the insulating adhesive layer 27 is thermoset. And a process.

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 multilayer wiring board.

[0002]

2. Description of the Related Art Various types of multilayer wiring boards are known. 9 to 14 show an example of a conventional method for manufacturing a multilayer wiring board. FIG. 9 shows a copper foil 1 on both surfaces of a base material (glass epoxy base material) 10 made of glass-filled resin.
1 and 11 are sheet materials 12 formed. As shown in FIG. 10, the copper foils 11 and 11 on both surfaces of the sheet material 12 are etched by photolithography to form wiring patterns 13 and 13 on both surfaces of the base material 10.

Next, as shown in FIG. 11, a through hole 14 penetrating through a required portion of the wiring patterns 13 and 13 is formed by pressing (punching). Next, although not shown, a solder sheet having a required thickness is overlaid on one wiring pattern 13, and the solder sheet is punched again by a punch (not shown) in which a through hole 14 is formed, as shown in FIG. The punched solder pole is pushed into the through hole 14 to form the via 15. The via 15 is formed so as to slightly protrude from the surface of the wiring pattern 13.

The laminated unit 16 formed as described above.
As shown in FIG. 13, an insulating adhesive layer (prepreg material)
A multilayer wiring board 18 can be manufactured by stacking a plurality of sheets with 17 interposed therebetween, and then thermally curing the insulating adhesive layer 17 by vacuum thermocompression bonding as shown in FIG. Via 1
5 and 5 are brought into contact with each other so as to push away the intervening insulating adhesive layer 17 to be electrically connected.

[0005]

The conventional method for manufacturing the multilayer wiring board 18 has the following problems. That is, since the base material 10 contains glass fiber,
Since a glass fiber with a very large thickness of at least about 100 μm and a high strength is contained, the punch for forming the through hole 14 in the base material 10 must inevitably have a large diameter with a high strength. Don't be. As a result, the through hole 14 has a large diameter of about several hundreds μm, and there is a limit to reducing the diameter, and there is a problem that the dense wiring pattern 13 cannot be formed. Also, between vias 15
The insulating adhesive layer 17 may remain and hinder the conductivity.

Accordingly, the present invention has been made to solve the above-mentioned problems, and the object of the present invention is to form fine vias and to form a dense wiring pattern, and to electrically connect vias. An object of the present invention is to provide a method of manufacturing a multilayer wiring board that can be reliably connected.

[0007]

In order to achieve the above object, a method for manufacturing a multilayer wiring board according to the present invention comprises: a. Forming a through hole in a required portion of the insulating base material by laser processing; b. Forming a wiring pattern electrically connected by a through-hole plating layer on both surfaces of the insulating base material; c. Forming an insulating adhesive layer on one surface of the first laminated unit obtained by the steps a and b so as to cover the wiring pattern; d.
Forming a via hole in the required part of the insulating adhesive layer by laser processing to expose the wiring pattern at the bottom; e. A filling step of filling the via hole with a solder paste to form a via; f. The second laminated unit obtained by the steps c, d, e and the first laminated unit are superposed and thermocompression bonded so that the corresponding via and the wiring pattern come into contact with each other, and solder paste is used. A thermocompression bonding step of melting the via and connecting to the corresponding wiring pattern, and thermosetting the insulating adhesive layer.

The insulating base material may be a resin base material that does not contain glass fibers.
In addition, the step of forming the wiring pattern b includes a step of forming an electroless plating film on the front and back surfaces of the insulating base material on which the through hole is formed and an inner wall of the through hole, and the electroless plating film on the electroless plating film. A photolithography process for forming a mask pattern with a resist exposed in a pattern according to a wiring pattern to be formed by an electroplating film, and a process for forming an electroplating film in the through hole and on the exposed electroless plating film; And then removing the mask pattern, and further removing the exposed electroless plating film by removing the mask pattern.

Further, the step of forming the via includes a step of further forming a protective film on the insulating adhesive layer in the step c, and the wiring pattern is exposed at a required portion of the protective film and the insulating adhesive layer. Forming a via hole by laser processing, a filling step of filling the via hole with a solder paste to form a via, and a step of peeling the protective film after forming the via.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. A manufacturing process is shown in FIGS. First, as shown in FIG. 1, a through hole 21 is formed in a required portion of the insulating base material 20 by laser processing. As the insulating base material 20, a polyimide resin film having a thickness of about 50 μm and not containing glass fibers can be used, but the insulating base material 20 is not limited to this. The laser processing is preferably a carbon dioxide laser, but is not limited thereto. By using a resin that does not contain glass fiber as the insulating base material, a diameter of 50 can be obtained by laser processing.
A through hole 21 having a fine hole diameter of about μm can be formed.

Next, as shown in FIG.
Wiring patterns 23 and 24 that are electrically connected by the through-hole plating layer 22 are formed on both surfaces of 0 and formed in the first laminated unit 25. A method for forming the through-hole plating layer 22 and the wiring patterns 23 and 24 is not particularly limited, but a semi-additive method is suitable for obtaining a fine pattern.

In the semi-additive method, although not shown, first, an electroless plating film is formed on the front and back surfaces of the insulating base material 20 in which the through holes 21 are formed and on the inner walls of the through holes 21. Next, on the electroless plating film, a mask pattern made of dry film exposed in 24 patterns of wiring patterns 23 and 24 to be formed by the electroless plating film is formed by a photolithography method. Note that a photosensitive resist layer may be formed by applying a photosensitive resist instead of a dry film. Next, an electrolytic copper plating film is formed in the through hole 21 and on the exposed electroless plating film, then the mask pattern is removed, and the mask pattern is further removed to remove the exposed electroless plating film. To do.

Next, as shown in FIG. 3, an insulating adhesive layer (prepreg material) 27 is laminated on one surface of the first laminated unit 25 so as to cover the wiring pattern 23, and further on the insulating adhesive layer 27. The protective film 28 is laminated and preliminarily thermocompression bonded. This temporary thermocompression is sufficient if the material can be fixed, and does not completely cure the insulating adhesive layer 27. For the insulating adhesive layer 27, a modified polyimide resin that is cured at a relatively low temperature of about 250 ° C. can be suitably used. A polyimide film can be used as the protective film 28, but any material can be used as long as it can be easily peeled off from the insulating adhesive layer 27. Both the insulating adhesive layer 27 and the protective film 28 may have a thickness of about 50 μm, but are not limited thereto.

Next, as shown in FIG. 4, the protective film 2
8 and the required portion of the insulating adhesive layer 27 on the wiring pattern 2
A via hole 30 in which 3 is exposed at the bottom is formed by laser processing. This laser processing can also be performed by a carbon dioxide laser, but is not limited thereto. Diameter 5
A fine through hole 30 of about 0 μm can be formed.

Next, as shown in FIG.
The via 31 is formed by filling the inside with a solder paste by a screen printing method. After the via 31 is formed, the protective film 28 is peeled off. As a result, the via 31 whose end portion slightly protrudes from the surface of the insulating adhesive layer 27 can be formed. As described above, the second stacked unit 32 shown in FIG. 5 is formed.

As described above, the protective film 28 serves to protect the solder paste from adhering to the surface of the insulating adhesive layer 27 in order to form the vias 31 with slightly protruding ends. If the solder paste can be filled in 30 so as not to adhere to the surface of the insulating adhesive layer 27, the protective film 28 is not necessarily provided.

Next, as shown in FIG. 6, the second laminated unit 32 and the first laminated unit 25 are superposed and thermocompression bonded so that the corresponding via 31 and the wiring pattern 24 are in contact with each other. In the illustrated example, the second stacked unit 32 is stacked three layers below, and one first stacked unit 2 is provided on the outermost layer.
5 was piled up.

As shown in FIG. 7, the air between each unit is discharged by this thermocompression bonding, and the insulating adhesive layer 27 is thermally cured and integrated, and the via 31 made of a solder paste by heat at the time of thermocompression bonding. Melts and is securely connected to the corresponding wiring pattern 24. In this way, the multilayer wiring board 34 can be obtained. In addition, as shown in FIG. 8, you may make it form the soldering resist layer 35 in front and back so that a part of wiring patterns 23 and 24 of surface layer may be exposed.

(Supplementary note 1) In the method of manufacturing a multilayer wiring board, a. Forming a through hole in a required portion of the insulating base material by laser processing; b. Forming a wiring pattern electrically connected by a through-hole plating layer on both surfaces of the insulating base material; c. Forming an insulating adhesive layer over the wiring pattern on one surface of the first laminated unit obtained by the steps a and b; d. Forming a via hole in the required portion of the insulating adhesive layer by laser processing in which the wiring pattern is exposed at the bottom; e. A filling step of filling the via hole with a solder paste to form a via; f. The second laminated unit obtained by the steps c, d, e and the first laminated unit are superposed and thermocompression bonded so that the corresponding via and the wiring pattern come into contact with each other, and solder paste is used. A method of manufacturing a multilayer wiring board, comprising: a thermocompression bonding step of melting the via and connecting to the corresponding wiring pattern, and thermosetting the insulating adhesive layer. (Additional remark 2) The manufacturing method of the multilayer wiring board of Additional remark 1 characterized by using the resin-made base material which does not contain glass fiber for the said insulation base material. (Supplementary Note 3) The step of forming the wiring pattern b is
A process of forming an electroless plating film on the front and back surfaces of the insulating base material in which the through hole is formed and an inner wall of the through hole, and a pattern according to the wiring pattern to be formed on the electroless plating film on the electroless plating film A photolithography process for forming a mask pattern with an exposed resist, a process for forming an electrolytic plating film in the through hole and on the exposed electroless plating film, and then removing the mask pattern, 3. A method for producing a multilayer wiring board according to claim 1, further comprising a removing step of removing the electroless plating film exposed by removing. (Supplementary Note 4) The step of forming the via includes a step of further forming a protective film on the insulating adhesive layer in the step c.
Forming a via hole in the required portion of the protective film and the insulating adhesive layer by laser processing to expose the wiring pattern at the bottom; filling a solder paste into the via hole to form a via; and via 4. The method of manufacturing a multilayer wiring board according to claim 1, further comprising a step of peeling off the protective film after the formation. (Additional remark 5) The 1st lamination | stacking unit in which the wiring pattern electrically connected by the through-hole plating layer which penetrates this insulation base material was formed in both surfaces of the insulation base material, and this insulation on both surfaces of an insulation base material A wiring pattern to be electrically connected is formed by a through-hole plating layer penetrating the base material, and an insulating adhesive layer is formed to cover one wiring pattern, and the one wiring pattern is formed on the bottom of the insulating adhesive layer. An exposed via hole is formed, and the via layer is filled with a solder paste and a via is formed, and the first laminated unit and the second laminated unit correspond to each other. The via pattern is superposed so that the via and the wiring pattern are in contact with each other, and the via pattern is melted by the solder paste to correspond to the wiring pattern. A multilayer wiring board, wherein the insulating adhesive layer is thermoset and integrated.

[0020]

As described above, according to the method for manufacturing a multilayer wiring board according to the present invention, since via holes are formed by laser processing, fine vias can be formed and a dense wiring pattern can be obtained. In addition, since the via melts and adheres to the wiring pattern at the time of thermocompression bonding, there is an effect that electrical connection between the wiring patterns can be surely performed.

[Brief description of the drawings]

1 to 8 show manufacturing process diagrams,

FIG. 1 is an explanatory diagram of a state in which a through hole is provided in an insulating base material,

FIG. 2 is an explanatory diagram of a first laminated unit in which wiring patterns are formed on both surfaces of an insulating base material;

FIG. 3 is an explanatory view showing a state in which an insulating adhesive layer and a protective film are thermocompression bonded to one surface of the first laminated unit;

FIG. 4 is an explanatory view showing a state in which a via hole is formed in a protective film and an insulating adhesive layer;

FIG. 5 is an explanatory diagram of a second stacked unit in a state where vias are formed;

FIG. 6 is an explanatory diagram of a state in which the first laminated unit and the second laminated unit are overlaid;

FIG. 7 is an explanatory diagram of a multilayer wiring board;

FIG. 8 is an explanatory diagram of a state in which solder resist layers are provided on both sides, and FIGS. 9 to 14 are process diagrams showing an example of a conventional method for manufacturing a multilayer wiring board;

FIG. 9 is an explanatory diagram of a double-sided copper-clad base material.

FIG. 10 is an explanatory diagram of a state in which a wiring pattern is formed on both surfaces of the base material;

FIG. 11 is an explanatory diagram of a state in which a through hole is formed in a required portion of the wiring pattern;

FIG. 12 is an explanatory diagram of a state in which a via is embedded in a through hole by punching;

FIG. 13 is an explanatory diagram of a state in which a plurality of stacked units are stacked;

FIG. 14 is an explanatory diagram formed on a multilayer wiring board by thermocompression bonding.

[Explanation of symbols]

20 Insulating base material 21 Through hole 22 Through-hole plating film 23, 24 Wiring pattern 25 First laminated unit 27 Insulating adhesive layer 28 Protective film 30 Beer Hall 31 Via 32 Second laminated unit 34 Multilayer wiring board 35 Solder resist layer

──────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme code (reference) H05K 3/28 H05K 3/28 F // B23K 101: 42 B23K 101: 42 F-term (reference) 4E068 AF01 DA11 5E314 BB02 CC15 FF05 GG24 5E346 AA43 CC04 CC10 FF13 FF18 GG15 HH07

Claims (4)

[Claims] 1. A method of manufacturing a multilayer wiring board comprising: a. Forming a through hole in a required portion of the insulating base material by laser processing; b. Forming a wiring pattern electrically connected by a through-hole plating layer on both surfaces of the insulating base material; c. Forming an insulating adhesive layer on one surface of the first laminated unit obtained by the steps a and b so as to cover the wiring pattern; d. Forming a via hole in the required portion of the insulating adhesive layer by laser processing in which the wiring pattern is exposed at the bottom; e. A filling step of filling the via hole with a solder paste to form a via; f. The second laminated unit obtained by the steps c, d, e and the first laminated unit are superposed and thermocompression bonded so that the corresponding via and the wiring pattern come into contact with each other, and solder paste is used. A method of manufacturing a multilayer wiring board comprising: a thermocompression bonding step of melting the via and connecting to the corresponding wiring pattern, and thermosetting the insulating adhesive layer. 2. The method of manufacturing a multilayer wiring board according to claim 1, wherein a resin base material not containing glass fibers is used as the insulating base material. 3. The step of forming the wiring pattern b includes a step of forming an electroless plating film on the front and back surfaces of the insulating base material in which the through hole is formed and an inner wall of the through hole, and on the electroless plating film. A photolithography process for forming a mask pattern with a resist that is exposed in a pattern according to the wiring pattern to be formed by the electroless plating film, and an electrolytic plating film is formed in the through hole and on the exposed electroless plating film 3. The manufacturing of a multilayer wiring board according to claim 1, further comprising: removing the mask pattern, and further removing the exposed electroless plating film by removing the mask pattern. Method. 4. The step of forming the via includes a step of further forming a protective film on the insulating adhesive layer in the step c, and the wiring pattern is exposed at a required portion of the protective film and the insulating adhesive layer. Forming a via hole by laser processing, filling a solder paste into the via hole to form a via, and peeling the protective film after forming the via. Item 4. A method for producing a multilayer wiring board according to Item 1, 2 or 3.