JP2002270997A - Method for manufacturing wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a wiring board where a wiring pattern is formed without using chemicals. SOLUTION: A laminate 5 where metallic foils 4 and a semi-hardenable resin sheet 3 are laminated is sandwiched by two metallic molds 1 and 2 where projecting wiring patterns 1-b and 2-b are formed on metallic plates 1-a and 2-a. The wiring board, where a metallic foil is cut at the projecting part of the metallic mold, the projecting wiring pattern is transferred on the surface of the laminate and the wiring pattern is formed, is manufactured. The projecting and recessing shape of the metallic mold where the wiring pattern is formed is transferred to the laminate where semi-hardenable resin is sandwiched by the metallic foils by the method of hot press. Thus, resource can be economized since the chemicals are not used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a wiring pattern on a wiring board used in electronic equipment.

[0002]

2. Description of the Related Art An outline of a conventional method for forming a wiring pattern on a wiring board will be described below.

[0003] First, a glass cloth is impregnated with a semi-curable resin such as epoxy, a copper foil is laminated on the surface thereof, and the resin is melt-cured by applying heat and pressure to bond the copper foil and the resin. An etching resist is applied or stuck on the surface of the double-sided copper-clad laminate, unnecessary portions of the wiring are masked and exposed, the resist in the non-wiring portion is removed with a cleaning solution, and the copper foil in the non-wiring portion is further etched with an etching solution. To remove. Thereafter, the etching resist remaining on the upper surface of the wiring portion is removed with a stripping liquid, and a wiring pattern on the surface of the wiring substrate is obtained. The wiring pattern thus obtained is characterized in that the copper foil wiring portion has a convex shape with respect to the surface of the wiring base material.

[0004]

In the conventional method, in order to form a wiring pattern on the surface of a wiring board, an etching resist for masking the wiring pattern portion is required, and a non-wiring pattern portion is formed. Therefore, a large amount of a dedicated chemical solution is used to remove the etching resist and the copper foil in the non-wiring portion. In addition, chemicals are used for cleaning the chemicals attached to the substrate for each step of using such chemicals. For the purpose of environmental protection, the used chemical waste liquid is collected and reused by performing necessary treatment, or is subjected to neutralization treatment and waste water treatment.

As described above, the conventional wiring pattern manufacturing technology requires the cost of purchasing and maintaining a large amount of chemicals, the capital investment for treating the waste liquid, and the cost of reuse. Using petroleum and natural resources to produce chemicals;
A so-called environmental problem arises with respect to wastewater. An object of the present invention is to propose a manufacturing method capable of minimizing the number of chemicals required for forming a wiring pattern as described above in order to solve such a problem.

[0006]

Means for Solving the Problems As a first step of forming a wiring pattern on the surface of a wiring board, molds having a wiring pattern convex portion corresponding to both surfaces after manufacturing the wiring board are each used for front and back sides. Prepare a total of two sheets. In the second step, a copper foil is laminated on both sides of the semi-curable resin sheet to form a laminate. Next, the laminate is sandwiched by the dies such that the surfaces of the two dies having the wiring pattern shapes are in contact with the surface of the laminate. In this state, it is inserted into a hot press capable of heating and pressing.

After insertion into the hot press, the semi-curable resin sheet is melted by heating by the hot press. Next, by pressing the laminate in the same hot press, a convex portion having a metal wiring shape is pressed into the metal foil on the surface of the laminate, and the metal foil is cut at the uneven portion. At this stage, the wiring shape of the convex portion of the mold is transferred to the laminate. By continuing heating, the semi-curable resin sheet is completely cured,
The metal foil is adhered while maintaining the irregular shape.
Thereafter, the hot press is cooled and depressurized, and the laminate sandwiched between the molds is taken out to obtain a single wiring board having a wiring pattern formed on the front and back surfaces. When manufacturing a large number of wiring boards with the same wiring pattern shape,
What is necessary is just to repeat from the said 2nd process.

According to the present method, a large number of wiring boards can be manufactured only by hot press molding by preparing a pair of molds having a convex portion of a wiring pattern shape. Etching resist, resist removal,
There is no need to use chemicals used for copper foil etching, resist stripping, cleaning, and the like.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a process of inserting and removing a laminate and a mold according to the present invention in a hot press and a partial cross section of a wiring board to be manufactured.

The upper mold 1 shown in FIG. 1A is formed by applying a wiring pattern-shaped convex portion 1-b to one surface of a metal flat plate 1-a manufactured in another process in advance. Lower mold 2 is upper mold 1
In the same manner as described above, a metal pattern 2-a is provided with a wiring pattern shape convex portion 2-b on one surface. The wiring patterns of the upper mold 1 and the lower mold 2 may be different circuit patterns depending on the purpose of the circuit. The details of the wiring pattern shape providing method will be described later.

Next, a metal foil 4 is laminated on both sides of a resin sheet 3 in which glass is impregnated with a semi-curable resin to form a laminate 5, and the laminate 5 is formed by combining the upper mold 1 and the lower mold 1 described above. 2 and inserted into a hot press (not shown) capable of heating and pressing. In the case of this embodiment, the thickness of the resin sheet 3 is about 0.8 mm, and the thickness of the metal foil 4 is 0.018 m.
m, and the planar size is about 500 × 500 mm. After being inserted into the hot press, the resin of the resin sheet 3 is once melted by heating to make the resin deformable. Next, the convex portion of the wiring pattern contacting the laminated body 5 of the upper mold 1 and the lower mold 2 is pressed into the metal foil 4 and the resin sheet 3 constituting the laminated body by pressing by the hot press, and at the same time, as shown in FIG. -As shown in (B), until the surface of the concave portion of the mold and the surface of the metal foil 4 finally come into contact with each other, the metal foil 4 has a cross section 6 of the convex portions 1-b and 2-b of the mold. By cutting and ending the biting operation, the uneven shape of the wiring pattern of the upper mold 1 and the lower mold 2 is transferred to the laminate 5. In cutting the metal foil 4, the height of the convex portion of the mold is 1.5 times or more of the metal foil to be cut, that is, 0.045 m in the embodiment of the present invention.
If the height is not less than m, good cutting can be obtained. Next, the resin of the resin sheet is completely cured by holding the heating of the hot press in the state described above, and after the resin is solidified, the hot press is cooled and depressurized to remove the upper mold 1 and the lower mold. 2
The laminates 5 sandwiched between the molds 5 are collectively taken out from the hot press, and then the laminate 5 is removed from the upper mold 1 and the lower mold 2.
Is taken out, and the wiring board 7 is obtained. This state is shown in FIG.
-(C). Wiring board 7 thus obtained
Are the wiring pattern shapes 1-b and 2 of the convex portions given to the mold.
-B becomes the concave portion 7-a of the wiring board 7, and a current flows through the metal foil in this portion to have a function as a wiring circuit. As described above, in the present invention, no chemical such as an etching solution is used for forming the wiring pattern shape.

The protruding portion 7-b of the wiring board 7 is an unnecessary portion as a wiring circuit, but is cut off from the concave portion 7-a of the wiring board 7 which is an electric circuit, so that it is electrically insulated. Therefore, there is no problem as a wiring circuit. However, when the projections 7-b of the wiring board 7 are not required to connect the electronic element or another wiring board on the wiring board, for example, as shown in FIG. When the protruding portion 7-b of the wiring board 7 is removed by performing (buffering), a smooth wiring board is obtained.

Next, a method of forming the projections 1-b and 2-b serving as wiring pattern portions of the upper mold 1 and the lower mold 2 will be described with reference to FIG. Since the manufacturing method of the upper mold 1 and the lower mold 2 is the same, the method of manufacturing the lower mold 2 will be mainly described below. FIG. 3 is a schematic diagram illustrating a process of manufacturing the lower mold 2 using a partial cross section of the mold.

As shown in FIG. 3, in order to form a convex portion of the wiring pattern shape on one surface of the metal flat plate 2-a, one surface of the metal flat plate 2-a is machined by an end mill 8 to remove unnecessary portions. Thus, the lower mold 2 is obtained. Note that the depth of the concave portion needs to be 1.5 times or more the depth of the metal foil in order to cut the metal foil. According to this method, although a long time is required for machining, a large number of wiring boards can be manufactured using a pair of dies.

However, the mold can be manufactured by a conventional method described below. FIG. 4 is a view showing a process of manufacturing a mold using a partial cross section of the wiring board. First, as shown in FIG. 4 (A), in order to form a wiring pattern shape convex portion on one surface of the metal flat plate 2-a, an etching resist 9 is attached, and exposed and developed to remove an unnecessary portion of the etching resist. . Next, as shown in FIG. 4B, one side of the metal flat plate 2-a is etched using an etchant to form a recess 2-c. Next, as shown in FIG. 4C, the etching resist 9 is removed with a stripping solution, and the lower mold 2 is obtained. As described above, the mold can be manufactured by the conventional method, but it is necessary to use a chemical. However, as described above, in the present invention, since it is only necessary to use a chemical for the production of a pair of molds, no chemical is used every time a wiring pattern of a large number of wiring boards is formed unlike the conventional method. Compared with the conventional method, the amount of chemicals used can be reduced.

[0017]

According to the present method, since a large number of wiring boards can be manufactured only by hot press molding using a mold, for example, an etching resist, a resist removing liquid, and etching of a copper foil necessary for forming a conventional wiring pattern shape are performed. Chemicals used for the liquid, the resist stripping liquid, the cleaning liquid, and the like are not required. In addition, even if the method according to the prior art is used for mold manufacturing, since it is a chemical paint cloth used for etching resist, resist removal, copper foil etching, resist peeling, cleaning, etc. for each of a large number of wiring boards as in the past, The use amount of these chemicals can be reduced to about 1/10 of the conventional amount.

As a result, the amount of use of petroleum or natural resources can be reduced, which contributes to global environmental protection.

[Brief description of the drawings]

FIG. 1 is a schematic view simultaneously showing a step of inserting and removing a laminate and a mold according to the present invention in a hot press and a partial cross section of a wiring board to be manufactured.

FIG. 2 is a partial cross-sectional view of a smooth wiring board obtained by adding a polishing process to the wiring board according to the present invention;

FIG. 3 is a schematic diagram illustrating a step of manufacturing a lower mold 2 using a partial cross section of the mold.

FIG. 4 is a schematic diagram illustrating a conventional process of manufacturing the lower mold 2 using a partial cross section of the mold.

[Explanation of symbols]

1, upper mold, 1-a: metal flat plate, 1-b: convex wiring shape, 2 ... lower die, 2-a: metal flat plate, 2-b: convex wiring shape, 2-c: concave portion, 3 ... resin sheet, 4 ... metal foil, 5
... Laminate, 6 ... Measuring surface, 7 ... Wiring board, 7-a ... Recess, 7
-B: convex part, 8: end mill

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasushi Ideguchi 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Communications Division, Hitachi, Ltd. 5E339 AB02 AD03 BC02 BE02 5E343 AA02 AA12 BB24 BB67 DD54 DD80 EE33 FF30 GG20

Claims (3)

[Claims] 1. A laminated body in which a metal foil and a semi-curable resin sheet are laminated is sandwiched between two metal molds each having a convex wiring pattern formed on a metal flat plate, and the laminated state is subjected to hot pressing. After the insertion, after the semi-curable resin sheet is melted by heating by a hot press, by pressing by the hot press, a metal foil is cut at a convex portion of the metal mold and a concave shape is formed on the surface of the laminate. Transfer the wiring pattern,
Thereafter, after heating and curing the resin, the laminate is taken out from a hot press to produce a wiring board on which a wiring pattern is formed. 2. A method for forming a wiring pattern on a surface of a wiring substrate by removing the convex portion on the surface of the wiring substrate obtained in claim 1 by mechanical polishing. 3. The mold according to claim 1, wherein the height of the convex wiring pattern of the metal mold is at least 1.5 times the thickness of the metal foil laminated on the semi-curable resin sheet.