JPS6021598A - Method of producing multilayer wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a method for manufacturing a multilayer wiring board.

[Background technology]

Conventionally, when manufacturing this type of multilayer wiring board, as shown in FIG.
(Through hole on the substrate (2) on which 11 is formed) 3
) are perforated with an electrically insulating layer (4), and the circuit (11) and the through hole (3) are aligned,
Next, in this state, base & (2) and metal foil with electrical insulating layer (4
) are sandwiched between molding plates and heated and pressure-molded to form an integrated layer.Then, the through holes (3) are filled with conductive material (6) such as solder to bond the circuit (1) and the metal foil (6).
5) were electrically connected. However, in this method, the substrate (2) and the metal foil with an electrically insulating layer (4)
), there is a problem that the surface of the copper foil that forms the circuit (1) is oxidized in the air, so the through hole (31) is then filled with conductive material (6) to form the circuit (1). ) and the metal foil (5) on the surface are unreliable.

[Purpose of the invention]

The present invention has been made in view of the above points, and provides a method for manufacturing a multilayer wiring board that can improve reliability by preventing the circuit surface from being oxidized during molding. The purpose is to

[Disclosure of the invention]

That is, in the present invention, a metal foil (4) with an electrically insulating layer, which has through holes (3) formed on the surface of a substrate (2) on which a circuit film is formed, is placed so that the metal foil (5) is on the surface side. Place the metal foil (4) with an electrically insulating layer on the circuit board (2) and align the through hole (3) with the circuit (1) position.
), then fill the through hole (3) with a conductive material, and then bond the substrate (2) and the metal foil with an electrically insulating layer (4).
The above object has been achieved by a method of manufacturing a multilayer wiring board, which is characterized in that the multilayer wiring board is sandwiched between molding plates and laminated and molded.

The present invention will be explained in detail below with reference to Examples. As the substrate (2), a metal base substrate, a resin substrate, a flexible substrate, a single-sided substrate, a double-sided substrate, a multilayer substrate, etc. thereof can be used, and the present invention is not limited thereto. As shown in FIG. 2(a), grooves (v&fl) are formed on the surface of this substrate (2). A metal foil (4) with an electrically insulating layer is formed on the substrate (2) with through holes (3) as shown in FIG.
) are placed on top of each other so that the metal foil (5) is on the front side, and the through hole (3) is aligned with the circuit fl) position. Here, the metal foil (5) can be formed of copper foil, and the electrical insulating layer 03) can be formed of a resin layer such as fi ultraviolet curing resin or thermoplastic resin, prepreg, bondi-shiji sheet, etc. be able to. Next, this board (2
) and the metal foil with the electrically insulating layer (4) are put together in a pair, and the metal with the electrically insulating layer is heated by applying insufficient heat to harden the electrically insulating layer (13). Foil (4) to substrate (2)
Temporarily adhere to. Next, as shown in Figure 2 (bl), a conductive material (6) such as solder paste or conductive paste is embedded into the through hole (3) from the surface by printing or coating, and then the substrate is coated as necessary. (2) is slightly heated to evaporate the abrasions in the conductive material such as solder paste, and then the substrate (2) and the metal foil with an electrically insulating layer (4) are heated.
) and the electrically insulating layer (1 layer) is heat-pressed and molded by applying sufficient heat to completely cure the electrically insulating layer.The heating temperature at that time is the melting temperature of the above-mentioned conductive material (6) or higher. In this way, a multilayer wiring board A is obtained in which the electrically insulating layer-coated metal foil (4) is laminated and integrated on the board (2).

Therefore, when laminating and molding the substrate (2) and the metal foil with an electrically insulating layer (4), the through holes (3) are formed while the metal foil with an electrically insulating layer (4) is temporarily bonded to the substrate (2) in advance.
By filling the inside with the conductive material (6), the surface of the circuit f1 of the substrate (2) is protected by the conductive material (6) and will not be oxidized during subsequent heating and pressure molding. It is something. Furthermore, by filling the through hole (3) with a four-electrode material (6) such as solder paste, it is possible to prevent air from entering the through hole (3j) and improve reliability. Furthermore, it is easy to print solder paste to form the through holes (3), and the reliability of the through holes can be improved.Also, a second layer is applied to the surface of the multilayer wiring board A formed in this way. When forming a circuit, the etch resist adheres well to the solder paste, and the through-hole lands can be completely protected during etching.

〔Effect of the invention〕

As described above, the present invention involves placing a metal i with an electrically insulating layer on which a through hole is formed on the surface of a substrate on which a circuit is formed so that the metal foil is on the surface side, and placing the through hole at the circuit position. Next, the metal foil with an electrically insulating layer was temporarily bonded to the board, and then the through-hole was filled with a conductive material, and then the board and the metal foil with an electrically insulating layer were sandwiched between molding plates and laminated. By filling the through holes with a conductive material in advance, the circuit surface of the board can be protected with the conductive material, and the circuit surface can be prevented from being oxidized during molding. This can improve reliability when

[Brief explanation of drawings]

FIGS. 1(a), (b), and (c) are sectional views of essential parts showing a conventional manufacturing method, and FIGS. 2(a), (b), and (c) are sectional views of essential parts of an embodiment of the present invention. . 111 is a circuit, (2) is a board, (3) is a through hole,
(4) is metal foil with electrical insulation layer, (6) is metal foil, (6)
is a conductive material. Agent Patent Attorney Ishi 1) Kenshichi

Claims (1)

[Claims] +1) Place the metal foil with an electrically insulating layer on the surface of the board with the circuit formed on its surface so that the metal foil is on the surface side, align the through hole with the circuit position, and then remove the electrically insulating layer. A multilayer wiring board characterized in that a layered metal foil is temporarily bonded to a substrate, a conductive material is then filled in the through holes, and then the substrate and the electrically insulating layered metal foil are sandwiched between molding plates and laminated and molded. manufacturing method.