JP2002344132A - Manufacturing method of printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a printed board hardly deformed and having superior conductivity only by a dry process easily without contaminating circumstances. SOLUTION: After a sheet of paper 2 is stuck to both faces of a base 1 made of insulating material with a water-soluble glue, each through hole 3 is formed at necessary positions. After the inside of the through hole 3 is filled with a conductive paste 4 in such a manner that the face of the through hole 3 is made flush with the surface of the paper 2, the paper 2 is peeled. A copper foil with an adhesive stuck on one face thereof is stuck to both faces of the base 1 in such a manner that the face of the copper foil is jointed to the surface of the conductive paste 4. After that, the copper foil is etched to form a wiring pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for manufacturing a printed circuit board.

[0002]

2. Description of the Related Art In order to manufacture a printed circuit board, copper foil is laminated on both sides of an insulating base material.
After opening the hole, plating with copper or the like is performed, and the copper foil on both sides is often electrically connected through the through hole covered with the plating layer. However, when forming a pattern with a copper foil, even the plating layer on the surface must be etched, making it difficult to form a fine circuit.

[0003] Conventionally, through holes are formed at necessary portions of an insulating substrate, and after filling the through holes with a conductive paste, both surfaces of the insulating substrate are filled with conductive layers for wiring so that the conductive paste is sealed. A method for conducting between both sides of a surface printed wiring board to be coated is disclosed in JP-A-54-38562. According to the above-mentioned conventional method, there is no fear that conduction between the conductive layers on both sides is not obtained due to burrs or warpage of the conductive layer generated at the time of forming the through hole, the conduction resistance can be reduced, and the through hole is filled with the conductive paste. Therefore, deformation such as shrinkage of the substrate can be prevented. However, when the conductive layers are laminated on both sides of the insulating substrate, when hot pressing and plating are performed at a high temperature and a high pressure, the operation is troublesome, the cost is high, and the substrate is easily deformed.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for manufacturing a printed circuit board which can be easily formed by using only a dry manufacturing method without polluting the environment by using a dry manufacturing method. That is the task.

[0005]

According to the method of manufacturing a printed circuit board of the present invention, a paper is stuck on both sides of a base material made of an insulating material, and then through holes are formed at necessary places. The inside of the hole is filled with a conductive paste so that the surface is flush with the surface of the paper, and then the paper is peeled off.
Next, on both surfaces of the base material, a copper foil having an adhesive adhered to one surface is attached so that the copper foil surface is bonded to the surface of the conductive paste, and then the copper foil is etched to form a wiring pattern. It is characterized by. By attaching a copper foil with an adhesive, a conductive layer can be easily formed on both surfaces of the substrate. After a through-hole is opened in the base material on which the paper is pasted, the through-hole is filled with a conductive paste, and then the paper is peeled off so that the conductive paste has a surface equivalent to the thickness of the paper. The conductive paste protrudes from the adhesive when the copper foil is attached, and as a result, the copper foil and the conductive paste are electrically connected.

[0006] Paper may be adhered to the substrate via a water-soluble glue. With the configuration using a water-soluble glue for sticking the paper, the paper can be easily peeled off only by washing with water or hot water.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. In order to manufacture a printed circuit board, first, paper 2 having water-soluble glue adhered to one surface is attached to both surfaces of a substrate 1 (FIG. 1) made of an insulating material (FIG. 2). The base material 1 is made of a suitable material such as a glass / epoxy material or BT resin, and a suitable material is selected according to the type of the mounted device and the use conditions. As the paper 2, bran paper or the like having good workability of drilling holes is used.

Next, as shown in FIG. 3, a through hole 3 is formed by drilling a hole where conduction is required. The diameter of the through hole 3 is generally 0.1
5 mm to 0.3 mm. Thereafter, as shown in FIG. 4, the through holes 3 are filled with a conductive paste 4 such as a silver paste or a copper paste. In order to fill the conductive paste 4 into the through holes 3, a screen mold is placed on the surface of the paper 2, and the conductive paste 4 is extruded from above with a squeegee by so-called screen printing or the like. Is flush with the surface of the paper 2.

[0009] Next, when washed with water or hot water, the water-soluble glue dissolves, and the paper 3 peels off as shown in FIG. 1 from the surface. Next, as shown in FIG. 6, a copper foil 5 having an adhesive adhered to one side is adhered to both sides of the substrate 1. Then, the portion of the conductive paste 4 protruding from the surface of the base material 1 pushes away the adhesive adhered to the copper foil 5, and the surface of the conductive paste 4 and the foil surface of the copper foil 5 are joined, and electrically. Connected. As a result, the copper foils 5 on both sides are conducted through the conductive paste 4 filled in the through holes 3.

[0010] After that, like the conventional printed wiring,
The surface of the copper foil 5 is covered with an etching resist, and is exposed and developed to leave the etching resist in the pattern portion. Further, unnecessary portions of the copper foil 5 are removed by etching, and finally the etching resist is removed. Form a wiring pattern. In addition, it is possible to attach a weak adhesive agent to one side of the paper 2 and attach it to the substrate 1. However, in order to prevent displacement during drilling, it is easy to peel off, and the adhesive force is low. It is advantageous to use a strong water-soluble glue.

[0011]

According to the first aspect of the present invention, since the through-holes of the base material are filled with the cured conductive paste, deformation such as shrinkage hardly occurs even when laminating, and the conductivity is good. In addition, impedance control necessary for a high-frequency circuit or the like is easy. In addition, since there is no need to perform plating, a wiring pattern can be formed only by etching the copper foil, and it can be completely manufactured only by a dry manufacturing method, and there is no fear of polluting the environment. further,
By attaching copper foil with adhesive, conductive layers can be easily formed on both sides of the base material, and the part of the conductive paste protruding from the base material surface pushes away the adhesive attached to the copper foil, It is securely connected to the copper foil. According to the second aspect of the present invention, the paper can be easily peeled off only by washing with water or hot water.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first step of a method for manufacturing a printed circuit board.

FIG. 2 is a sectional view showing a second step of the method for manufacturing a printed circuit board;

FIG. 3 is a sectional view showing a third step of the method for manufacturing a printed circuit board.

FIG. 4 is a sectional view showing a fourth step of the method of manufacturing a printed circuit board.

FIG. 5 is a sectional view showing a fifth step of the method for manufacturing a printed circuit board.

FIG. 6 is a sectional view showing a sixth step of the method for manufacturing a printed circuit board;

[Explanation of symbols]

 1 base material 2 paper 3 through hole 4 conductive paste 5 copper foil

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E314 AA21 BB03 BB12 CC15 DD10 FF05 GG24 5E317 AA24 BB01 BB02 BB12 BB14 CC22 CC25 CD27 GG16 5E339 AB02 AC01 AD03 AE01 BC01 BC02 BD02 BD03 BD06 BD07 BD13 BE13 CE04 DD16 CF17 CG

Claims (2)

[Claims] After pasting paper on both sides of a base material made of an insulating material, a through hole is formed at a necessary place, and then a conductive paste is placed inside the through hole, and the surface of the through hole is coated with the conductive paste. After filling so as to be flush with the surface of the paper, the paper is peeled off, and then, on both surfaces of the base material, a copper foil having an adhesive adhered to one surface is bonded to the surface of the conductive paste on a copper foil surface. A method of manufacturing a printed circuit board, comprising: adhering as much as possible, and then etching the copper foil to form a wiring pattern. 2. The method for manufacturing a printed circuit board according to claim 1, wherein the paper is adhered to the base via a water-soluble glue.