JP2001144445A - Method for producing multilayer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a multilayer printed wiring board having high reliability and excellent dimensional stability in which interlayer integration can be carried out simultaneously with electrical connection through a simple method. SOLUTION: A conducted board made of an insulating hard plate provided, on the substantially smooth surface and backside thereof, with wiring patterns of conductive layer and having through holes filled with conductive paste, and a film provided, on one side thereof, with a wiring pattern of conductive or nonconductive layer and having through holes filled with conductive paste in a semi-cured insulating resin layer are integrated by press. Subsequently, the semi-cured resin and the conductive paste are cured and electrical interlayer connection is made between the conducted smooth board and the wiring pattern of each film.

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 printed wiring board of an electric circuit used for a liquid crystal display device, a semiconductor device, and other electric products.

[0002]

2. Description of the Related Art Conventionally, a printed wiring board having a multilayer structure is manufactured by using a single-sided or double-sided copper-clad laminate as a substrate, and repeating a process of forming a circuit pattern, resin coating, drilling, and forming a through hole by plating. Have been. Other manufacturing processes have also been proposed. However, with the demand for higher density and further multi-layering, in the conventional method, since it is necessary to repeatedly stack each layer, the process becomes complicated, resulting in a decrease in yield and an increase in cost. Problems have also been pointed out in terms of heat resistance, dimensional stability, and connection stability between layers of the obtained printed wiring board.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a highly reliable multi-layered printed wiring board, in which the integration of layers and the electrical connection can be performed simultaneously by a simple method.

[0004]

According to a method of manufacturing a multilayer printed wiring board of the present invention, a wiring pattern of a conductive layer is formed on an upper surface and a lower surface of an insulating hard plate, and the wiring pattern is formed on a substrate. A smooth substrate is prepared in which the front surface is buried so that the front surface and the back surface are practically smooth, and a through hole is formed in the smooth substrate to allow the front surface wiring pattern and the back surface wiring pattern of the smooth substrate to communicate with each other. The inside is filled with a conductive paste to form a conductive smooth substrate. On the other hand, a conductive layer or a wiring pattern of the conductive layer is formed on one surface, and a semi-cured insulating resin layer is provided. A laminating film filled with conductive paste in the holes is prepared, and at least one or more laminating films are provided on the front and back surfaces of the conductive smoothing substrate, and the conductive smoothing substrate surface and the laminating film are laminated. The insulating resin layer in the cured state is overlapped with the wiring pattern or the wiring pattern and the conductive layer so as to face each other, and then the lamination film is integrated with the front and back surfaces of the conductive smooth substrate by pressing. Curing the semi-cured resin of the film for lamination and the conductive paste, and electrically connecting the conductive smoothing substrate and the wiring pattern or conductive layer of each film for lamination. The laminating film can be formed by laminating one or more layers, or any number of layers, on both surfaces of the conductive smoothing substrate. Even in the case of laminating a plurality of layers, it is possible to obtain a multilayer printed wiring board by integrating and electrically connecting the conductive smoothing substrate and each laminating film by one press.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the manufacturing method of the present invention, a smooth substrate and a film for lamination are laminated and integrated, and between the smooth substrate and the film for lamination, and when a plurality of films for lamination are laminated, the lamination Make electrical connections between the films. FIG. 1 is a sectional view showing an embodiment of a smooth substrate used in the present invention. The smooth substrate 11 has a wiring pattern 3 made of a metal film (conductive layer) such as copper on the surface of the smooth substrate body 13.
1 is formed. The smooth substrate body 13 is made of an insulating hard plate, and is formed of a hard core layer 15 and a hardened resin layer 17 having an embedded wiring pattern 31. Can be formed as an integral body.

The hard core layer 13 is formed by impregnating a glass cloth with an epoxy resin, an amide resin, a phenol resin, a Teflon, a BT resin and the like, and curing the glass cloth. Cured resin layer 17
Is obtained by heating and curing a semi-cured resin such as a thermosetting resin such as an epoxy resin in the same manner as described above. in this way,
Since the smooth substrate 11 is formed of a rigid hard plate, the obtained multilayer printed wiring board has excellent dimensional stability.

FIG. 2 shows an example of a method for manufacturing the smooth substrate 11. A semi-cured resin layer 17 'is provided on both sides of the hard core layer 15,
A wiring pattern 31 is formed thereon by an appropriate method such as a resist method. Then, by hot pressing from both sides with the end plates 19, 19, as shown in FIG. 1, the semi-cured resin layer 17 'is thermally cured to be converted into the cured resin layer 17 and the wiring is formed. The pattern 31 is buried and fixed in the cured resin layer 17 with its surface exposed to the cured resin layer 17, and the smooth substrate 11 shown in FIG. 1 is obtained.

Next, as shown in FIG.
, A through hole 25 is formed. When drilling the through-hole 25, a mask pattern is used. In FIG.
A mask pattern film 29 made of a synthetic resin such as a polyethylene terephthalate film or the like to be formed with holes is laminated on the portion where the is provided.

After laminating the mask pattern film 29, a through hole 25 is formed through the mask pattern film 29 in the thickness direction of the smooth substrate body 13. Next, by a roll coater or the like, if necessary, under vacuum,
The conductive paste 27 is filled in the through holes 25. The conductive paste 27 contains a metal powder such as silver or copper, and will harden in the future in the process of the present invention, and shows conductivity in a hardened state.
A drill, a laser beam, or the like is used to form the through holes 25.

Next, by peeling off the mask pattern film 29, as shown in FIG. 4, a conductive smooth substrate 21 having a through hole 25 and a conductive paste 27 filled in the through hole 25 is obtained. . The conductive paste 27 protrudes from the surface of the conductive smooth substrate 21 by the thickness of the mask pattern film 29. Also, by filling the conductive paste 27 into the through holes 25 without using the mask pattern film 29, as shown in FIG.
The conductive smooth substrate 21 in which the conductive paste 27 does not protrude from the surface of the smooth substrate can also be manufactured.

The laminating film 41 comprises a conductive layer 43 and a semi-curable resin layer 45, as shown in FIG. Generally, RCC (Resin Coated Cupper)
A material obtained by applying a semi-curable resin to a copper foil called a so-called copper foil or a material obtained by attaching a semi-curable resin to a copper foil can also be used. The conductive 43 is made of a metal layer such as a copper foil. The semi-curable resin layer 45 is made of a resin layer in a cured state,
It is generally called a non-flow resin or a low-flow resin, and a semi-cured epoxy resin, a phenol resin, an amide resin, a BT resin, a Teflon resin, or the like is used.

As shown in FIG. 7, a through-hole 47 is formed in the laminating film 41 and a conductive paste 49 is filled in the laminating film 41, as in the case of a smooth substrate. Also in this case, the conductive paste 49 may or may not protrude from the surface of the laminating film 41 as shown in FIG.

Next, as shown in FIG. 8, the laminating films 41, 41 are opposed to both surfaces of the conductive flat substrate 21 and hot pressed. As a result, the multilayer printed wiring board 51 shown in FIG. 9 is obtained. At this time, simultaneously with the pressing by the hot press, the semi-cured resin layer 45 is cured to integrate the conductive smoothing substrate 21 and the laminating film 41, and the through holes 25 of the conductive smoothing substrate 21 and the laminating film 41. ,
The conductive pastes 27 and 49 filled in 47 are cured to electrically connect the respective wiring pattern layers. On this occasion. When the conductive paste has the protruding portion, the reliability of the adhesion between the paste and the wiring pattern (circuit) is increased, and the density of the paste can be increased. The conductive layer 43 of the laminating film 41 may be formed with a wiring pattern in advance, or may be formed after being integrated with the conductive smoothing substrate 21.

As shown in FIG. 9, the multilayer printed wiring board has four wiring pattern layers of 1, 2, 3, and 4. FIG. 10 shows a multi-layer printed circuit board laminated in a multi-layer state before pressing. Conductive planar substrate 21
By laminating three layers of laminating films 41 on each of the front and back surfaces and hot pressing them, 1, 2, 3,
A multilayer printed wiring board having eight wiring pattern layers of 4, 5, 6, 7, and 8 and electrically connecting each layer is obtained. In FIG. 10, the conductive paste 49 does not protrude from the surface of the laminating film 41, but may protrude similarly to the case of FIG. 7.

As shown in FIG. 10, the conductive paste filled in the through holes can be directly electrically connected (hole on hole). In any of the smooth substrate 11 and the laminating film 41,
Holes that do not penetrate in the thickness direction (IVH: Inter Via)
(Hole) can also be formed.

[0016]

According to the present invention, interlayer integration and electrical connection can be simultaneously performed by a simple method, and a highly reliable printed wiring board can be obtained. Also, the dimensional stability is good.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a smooth substrate according to the present invention.

FIG. 2 is an explanatory sectional view showing an embodiment of a method for manufacturing a smooth substrate according to the present invention.

FIG. 3 is an explanatory cross-sectional view showing an embodiment of a method for manufacturing a conductive smooth substrate according to the present invention.

FIG. 4 is a cross-sectional view showing an embodiment of the conductive smoothing substrate of the present invention.

FIG. 5 is a cross-sectional view showing an embodiment of the conductive smoothing substrate of the present invention.

FIG. 6 is a cross-sectional view showing an embodiment of the film for lamination of the present invention.

FIG. 7 is a cross-sectional view showing an example of the laminating film of the present invention.

FIG. 8 is an explanatory sectional view showing an embodiment of the method for manufacturing a multilayer printed wiring board according to the present invention.

FIG. 9 is an explanatory sectional view showing an embodiment of the multilayer printed wiring board of the present invention.

FIG. 10 is an explanatory sectional view showing an embodiment of the multilayer printed wiring board of the present invention.

[Explanation of symbols]

 1, 2, 3, 4, 5, 6, 7, 8 Wiring pattern layer 11 Smooth substrate 13 Smooth substrate body 15 Hard core layer 17 Hardened resin layer 19 End plate 21 Conductive smoothing substrate 25 Through hole 27 Conductive paste 29 Mask pattern Film 31 wiring pattern 41 laminating film 43 conductive layer 45 semi-curable resin layer 47 through hole 49 conductive paste 51 multilayer printed wiring board

Claims (1)

[Claims] 1. A wiring pattern comprising a conductive layer is formed on a front surface and a back surface of an insulating hard plate, and the wiring pattern is buried in a substrate so as to expose the front surface. A smooth smooth substrate is prepared in advance, a through hole is formed in the smooth substrate to allow the front surface wiring pattern and the back surface wiring pattern of the smooth substrate to communicate with each other, and a conductive paste is filled in the through hole to form a conductive smooth substrate. A lamination film is prepared in which a conductive pattern is formed on one side, a conductive layer or a conductive layer is formed, a semi-cured insulating resin layer is provided, and a conductive paste is filled in a through hole penetrating the resin layer. At least one or more laminating films on the front and back surfaces of the conductive smoothing substrate, and the conductive smoothing substrate surface and the semi-cured insulating resin layer of the laminating film, the wiring pattern of each other. The wiring pattern and the conductive layer are overlapped so that they face each other. Then, the laminating film is integrated on the front and back surfaces of the conductive smooth substrate by pressing, and the semi-cured resin of the laminating film is cured, and the conductive paste is formed. A method for manufacturing a multilayer printed wiring board, comprising: performing curing and performing electrical interlayer connection between a conductive smoothing substrate and a wiring pattern or a conductive layer of each laminating film.