JPH1027962A - Manufacture of multi-layer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a multi-layer wiring board having more layers by printing a resist on the surface of an insulating substrate on which a conductive pattern film is formed, performing flattening on the resist, forming an window on the surface of the resist so as to expose a part of the pattern film, forming a desired pattern of conductive paste on the surface of the resist, newly printing a resist on the surface of the pattern, and performing flattening on the resist. SOLUTION: A resist 3 is printed on both surfaces of an insulating substrate 1 including a conductive pattern film 4, then the surface of the resist 3 is set, and polishing processing is performed on the resist 3 to flatten the surface of the resist 3. A window 6 is formed at a desired position of the resist 3, to expose a part of the conductive pattern film 4. Conductive paste 9 is printed on both surface of the resist 3 including the window 6 and a through hole 8, into a desired pattern. Again, the resist 3 is printed on both surfaces of the resist 3 including the conductive paste 9, then the printed resist is set, and polishing processing is performed on the resist 3 to flatten the surface of the resist 3. Thus, the resist printing process and the conductive-paste printing process are repeated alternatively, to form a multi-layer wiring board having more layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a multilayer wiring board, and more particularly to a method for manufacturing a multilayer wiring board in which a conductive material and an insulating material are alternately laminated on the surface of an insulating substrate without plating.

[0002]

2. Description of the Related Art Wiring boards on which circuit components are mounted are used for assembling various electronic devices. However, due to demands for miniaturization and high-density mounting of electronic devices, conductive materials and wiring boards are used as wiring boards. 2. Description of the Related Art A multilayer wiring board is widely used in which insulating materials are alternately stacked so that wiring made of a conductive material is formed in multiple layers in the thickness direction of a wiring board.

Conventionally, in order to manufacture such a multilayer wiring board, a copper foil as a conductive material is stuck on an insulating substrate,
This copper foil is formed into a desired pattern by etching, and thereafter, the conductive pattern is covered with an insulating material, and a window exposing a part of the conductive pattern is opened at a desired position of the insulating material, and the conductive pattern is conducted through the window. A subtraction method in which a conductive material to be formed is formed so as to extend to a surface of an insulating material by plating treatment is generally performed.

FIGS. 3A to 3G show a manufacturing method utilizing such a subtraction method as an example of a conventional method for manufacturing a multilayer wiring board. The steps will be described below in the order of steps with reference to the drawings.

First, as shown in FIG. 3A, using an insulating substrate 1 on which a copper foil 2 is attached, as shown in FIG. 3B, only the surface of the copper foil 2 on which a conductive pattern is to be formed is formed. After the resist 3 is formed, the copper foil 2 not masked by the resist 3 is removed by performing an etching process as shown in FIG. 3C, and the resist 3 is removed as shown in FIG. By removing, the conductive pattern film 4 is formed.

Next, as shown in FIG. 3 (E), an insulating material 5 is formed on the surface of the insulating substrate 1 including the conductive pattern film 4, and etching is performed in the same manner as in FIGS. 3 (B) and 3 (C). By performing the processing, a window 6 is opened at a desired position of the insulating material 5 to expose a part of the conductive pattern film 4 as shown in FIG. Subsequently, a conductive material 7 is formed on the surface of the insulating material 5 including the window 6 by performing an electrolytic plating process.
By performing the same etching treatment as in (B) and (C), the conductive material 7 is formed in a desired pattern as shown in FIG.

As a result, a multilayer wiring board having the conductive pattern film 4 as the first layer wiring and the conductive material 7 as the second layer wiring is manufactured. Similarly, by repeating the steps of FIGS. 3E to 3G, it is possible to manufacture a multilayer wiring board having wiring of the third layer or more.

[0008]

However, in the conventional method for manufacturing a multilayer wiring board, it is necessary to repeatedly form a conductive material to be a wiring by plating, which complicates the process and increases the manufacturing cost. There was a problem of becoming.

Further, in the conventional manufacturing method, since the surface of each layer has irregularities, the surface is not smooth, so that there is a problem in mounting circuit components. A build-up method is known as another method of manufacturing a multilayer wiring board. However, the multilayer wiring board manufactured by this manufacturing method has low reliability because the peel strength of the pattern is weak. Furthermore, in general, the conventional manufacturing method cannot prevent entrapment of air bubbles at the time of manufacturing, so that the air bubbles reduce reliability.

The present invention has been made to solve such a problem, and an object of the present invention is to simplify a process when manufacturing a multilayer wiring board and to reduce manufacturing costs.

[0011]

A first method of manufacturing a multilayer wiring board according to the present invention is a method for manufacturing a multilayer wiring board in which a conductive material and an insulating material are alternately laminated on the surface of an insulating substrate, A step of printing a resist on the surface of an insulating substrate having a conductive pattern film formed on its surface, forming a window so as to expose a part of the conductive pattern after flattening the resist, and a resist including the window. A step of printing a solderable conductive paste on the surface of the resist to form a desired pattern, and a step of printing a new resist on the surface of the resist containing the conductive paste and flattening the resist. It is characterized by the following.

Further, the second aspect of the method for manufacturing a multilayer wiring board of the present invention.
The first one uses an insulating substrate in which a conductive pattern is formed on the front and back surfaces and a conduction hole is formed, and a conductive material and an insulating material are alternately laminated on both surfaces of the insulating substrate. It is characterized by doing.

According to the method of manufacturing a multilayer wiring board of the present invention, first, a resist is printed on the surface of an insulating substrate having a conductive pattern film formed on the surface, and the resist is flattened. After forming the window so as to expose the portion and printing a solderable conductive paste on the surface of the resist including the window, forming a desired pattern, a new resist is formed on the surface of the resist including the conductive paste. The resist is flattened, and thereafter, the step of printing the resist and the step of printing the conductive paste are alternately repeated, thereby manufacturing a multilayer wiring board on which more multilayer wiring is formed. It becomes possible. In addition, when an insulating substrate having a conductive pattern formed on the front surface and the back surface and a conduction hole is used, a multilayer wiring can be formed on both surfaces. Thereby, when manufacturing a multilayer wiring board, the process can be simplified and the manufacturing cost can be reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIGS. 1A to 1D and 2E to 2G are cross-sectional views showing an embodiment of a method for manufacturing a multilayer wiring board according to the present invention in the order of steps. Hereinafter, description will be made in the order of steps with reference to the drawings.

First, as shown in FIG. 1A, an insulating substrate 1 having a conductive pattern film 4 made of copper foil formed at desired positions on a front surface and a back surface and having a conduction hole 8 formed therein is prepared. I do. The conductive pattern film 4 is formed by attaching copper foil on both surfaces of the insulating substrate 1 in advance and then performing an etching process in a state where a desired position of the copper foil is masked.

Next, as shown in FIG. 1B, after a resist 3 is printed on both surfaces of the insulating substrate 1 including the conductive pattern film 4, the resist 3 is cured. As a material of the resist 3, for example, epoxy resin, polyimide resin, P
Using a PO resin or the like, a resin added with a substance having a function of improving, for example, heat resistance and high frequency characteristics is used in each of these resins. As the material of the resist 3, a material whose surface is roughened by its properties when cured is used. Thereby, the reliability of the connection between the layers can be improved.

Subsequently, as shown in FIG. 1 (C), the insulating substrate 1 is subjected to a buffing treatment to flatten the surface of the resist 3 to be printed.

Next, as shown in FIG. 1D, a window 6 is opened at a desired position of the resist 3 to expose a part of the conductive pattern film 4.

Subsequently, as shown in FIG. 2E, a solderable conductive paste 9 such as a copper paste is printed on both surfaces of the resist 3 including the windows 6 and the conduction holes 8 by printing the desired paste. Form into a pattern. This is done by printing the conductive paste 9 on the entire surface in advance and then removing the undesired portions, or by printing the conductive paste 9 in a state where a mask is formed on the undesired portions in advance to obtain the desired wiring to be formed. A pattern can be formed. At this time, the conductive paste 9 is also filled into the conduction holes 8 at the same time, so that a through-hole wiring is formed. Therefore, the conductive paste 9 on the front side of the insulating substrate 1 and the conductive paste 9 on the back side are separated. It becomes conductive through the through hole wiring. In addition, if a resin is used as the conductive paste 9 that allows bubbles to escape when the resin is cured, it is possible to prevent a decrease in connection reliability due to the inclusion of bubbles, particularly when printing the conductive paste 9 on the window 6. Can be.

Next, as shown in FIG. 2F, after the resist 3 is printed again on both sides of the resist 3 including the conductive paste 9, the resist 3 is cured. As the material of the resist 3, it is preferable to use the same material as that used in the step of FIG.

Subsequently, as shown in FIG. 2 (G), the insulating substrate 1 is again subjected to a buff polishing process to flatten the surface. As described above, the resist 3 which is an insulating material
In addition, it is possible to manufacture a multilayer wiring board in which the solderable conductive paste 9 which is a conductive material is formed by a printing method. By soldering the circuit component to the solderable conductive paste 9 of the multilayer wiring board thus obtained, the circuit component can be mounted in the same manner as a normal multilayer wiring board.

If necessary, FIGS. 2E to 2G
By repeating the above steps, a multilayer wiring board having four or more layers of wiring can be manufactured.

According to the method for manufacturing a multilayer wiring board of the present invention, not only a conductive material to be a wiring but also an insulating material is formed by printing without the need for plating treatment.
When manufacturing a multilayer wiring board, the process can be simplified and the manufacturing cost can be reduced. That is, the following effects are specifically obtained.

1. Since it can be manufactured using a general-purpose printing machine, polishing machine, or the like, no special equipment is required, so that capital investment can be minimized.

2. Since all the connections between the wirings are made with a conductive paste, plating equipment is not required.

3. By eliminating the need for special equipment as described above, the process is simplified, and the manufacturing cost can be reduced.

4. Since a conductive paste that can be soldered is used, expensive surface treatment such as gold plating, which was conventionally required, becomes unnecessary.

By covering the outermost layer of the multilayer wiring board with a conductive paste such as a copper paste, it is possible to provide an electromagnetic shielding effect, so that an improvement in electrical characteristics can be expected.

[0030]

As described above, according to the method for manufacturing a multilayer wiring board of the present invention, the conductive material and the insulating material which are to be wirings are formed by printing without the need for plating treatment. In this case, the manufacturing process can be reduced by simplifying the process.

[Brief description of the drawings]

FIGS. 1A to 1D are cross-sectional views showing the first half of a first embodiment of a method for manufacturing a multilayer wiring board of the present invention in the order of steps.

FIGS. 2E to 2G are cross-sectional views showing the latter half of the first embodiment of the method for manufacturing a multilayer wiring board of the present invention in the order of steps.

3A to 3G are cross-sectional views showing a conventional example of a method for manufacturing a multilayer wiring board in the order of steps.

[Explanation of symbols]

3 resist, 4 conductive pattern, 6 window, 8 conduction hole, 9 conductive paste.

Claims (3)

[Claims] 1. A method for manufacturing a multilayer wiring board comprising alternately laminating a conductive material and an insulating material on a surface of an insulating substrate, wherein a resist is printed on the surface of the insulating substrate having a conductive pattern film formed on the surface. Forming a window so as to expose a part of the conductive pattern film after flattening the resist, and printing a conductive paste solderable on a surface of the resist including the window to a desired pattern by printing. Forming a resist on the surface of the resist containing the conductive paste, and flattening the resist. 2. A method for manufacturing a multilayer wiring board, comprising alternately laminating a conductive material and an insulating material on a surface of an insulating substrate, wherein the conductive pattern film is formed on the front surface and the back surface, and the conduction hole is formed. Printing a resist on both sides of the conductive substrate, forming a window so as to expose a part of the conductive pattern film after flattening the resist, and soldering on both sides of the resist including the window and a hole for conduction. Printing a conductive paste that can be attached to form a desired pattern; andprinting a new resist on both sides of the resist containing the conductive paste, and flattening the resist. A method for manufacturing a multilayer wiring board, which is characterized in that: 3. The method according to claim 1, wherein the outermost layer is covered with a conductive paste.