JPH0384989A - Manufacture of cubic wiring board - Google Patents

Abstract

PURPOSE:To easily obtain a cubic wiring substrate by a method wherein a required conductor circuit is previously formed on the injection molded plane of at least one injection molding dies by electroplating and a required resin is injected and molded in said die so that a conductor circuit is transferred to be applied or buried in a predetermined plane of a resin molded product. CONSTITUTION:By using a male die 1 coated with a reverse pattern 4a and a plated resist layer 5 as an electrode on one side and a copper as an electrode on another side, the electro-copper-plating treatment in a copper sulfate plating bath is effected to form a conductor circuit 6 coating the exposed region of the injection molding plane 1a of the male die 1. Then after subjecting the male die 1 provided with the required conductor circuit 6 to water-cleaning and drying in order, the die 1 is assembled together with a female die 2 to compose an injection molding die 3 and these are set in a required injection molding device. In this injection molding die, a required resin, for example, a polycarbonate resin is injection molded. By this injection molding, the conductor circuit 6 on the molding plane 1a of the male die 1 is transported to be applied or buried in a plane of a resin molded product and these are made into one body to produce 9 resin molded product.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for manufacturing a three-dimensional wiring board.

(Prior Art) Attempts have been made to form a required conductor circuit on the inner wall surface of an insulating resin molded product, such as a housing, to make the structure of electronic devices more compact. In other words, it is known that the casing itself, whose original role is a mechanical or electrical protection function, can also be used as a conductive circuit board. However, a wiring board in which a resin molded product such as the above-mentioned casing is also used as a conductive circuit board is generally manufactured in the following manner. That is, the surface of the injection molded product is first subjected to chemical plating (electroless plating) and then to electroplating (electrolytic plating). Thereafter, an etching resist is printed on the electroplated layer, subjected to necessary exposure and development treatment, and then the plated layer other than the conductor circuit pattern forming area is selectively etched away. After forming a required conductor circuit on the surface of the injection molded product in this manner, the etching resist is removed by peeling or the like, thereby obtaining a desired wiring board (three-dimensional wiring board).

(Problems to be Solved by the Invention) However, in the case of the above-mentioned method for manufacturing a three-dimensional wiring board, there are the following problems, and it cannot be said that the method is fully satisfactory in practice. First of all, injection molding.

The process is complicated, including chemical plating pre-treatment (surface roughening treatment and catalyst treatment), chemical plating treatment, electroplating treatment, resist coating, exposure and development treatment, etching treatment, and resist peeling for a given surface of the molded product. Can be mentioned.

Second, since the surface of the substrate (injection molded product) is three-dimensional, it is not only difficult to apply a resist uniformly, but also the production of a mask used for exposure processing is complicated. Third, since conductor circuits are plated on the surface of the base (injection molded product), not only is the adhesion poor and the reliability is not satisfactory, but the resin that makes up the base (injection molded product) There are also problems such as being limited.

The present invention has been made in response to the above-mentioned circumstances, and includes steps,
A three-dimensional arrangement that simplifies operation and has a highly accurate and reliable conductor circuit! The purpose of the present invention is to provide a manufacturing method by which a substrate can be obtained.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a method in which a required conductor circuit and a reverse pattern are formed on the injection molding surface of at least one mold of an injection mold consisting of a male mold and a female mold. a step of depositing an insulating inorganic film; a step of applying an electroplating process to the injection molding surface of the mold on which the insulating inorganic film of the reverse pattern has been deposited to form a required conductor circuit; A special feature includes the steps of assembling the mold on which the conductor circuit has been deposited into an injection mold, injecting and molding the required resin into the mold, and transferring the conductor circuit onto the molding surface. shall be.

(Function) According to the present invention, the required conductor circuit is formed in advance by electroplating on the injection molding surface of at least one of the injection molds, and the required resin is injected into this mold. By molding, the conductor circuit is transferred or embedded in a predetermined surface of the resin molded product. In other words, a three-dimensional wiring board in which the required conductor circuits are firmly and tightly integrated can be simultaneously obtained in the injection molding process without requiring complicated operations and processes.

(Example) The present invention will be described in detail below with reference to FIGS. 1 to 6. FIGS. 1 to 6 are cross-sectional views schematically showing aspects of each step in the method for manufacturing a three-dimensional wiring board according to the present invention.

First, an injection mold 3 consisting of a male mold 1 and a female mold 2 having a configuration as shown in FIG. 1 is prepared. As shown in FIG. 2, a dense alumina layer 4 having a thickness of about 0.5 .mu.m was formed on the injection molded surface 1a of the sample 1 by a chemical paper position method using an organic metal compound such as trimethylaluminum. Alumina layer 4 deposited above
The surface of the male mold 1 was selectively cut using, for example, a diamond needle to expose the surface of the male mold 1 in the form of a required conductor circuit as shown in FIG.
remained). Next, a reverse pattern 4a of the male mold 1
A plating resist layer 5 was formed on the remaining injection molded surface 1a as shown in FIG. ff14. Electrolytic copper plating was performed in a sulfuric acid steel plating bath using the male mold 1 with the reverse pattern 4a and the plating resist layer 5 as one electrode and copper as a counter electrode, and as shown in FIG. A thickness of 15 mm is applied to the exposed area surface of the injection molding surface 1a of No. 1.
A conductive circuit 6 having a thickness of approximately μ was deposited and formed. After sequentially washing and drying the male mold 1 with the required conductor circuit 6 formed thereon, it is assembled into the female mold 2 and the injection mold 3 prepared in advance, and placed in the required injection molding machine. A desired resin, such as polycarbonate resin, was then injected into the injection mold.

By this injection molding, the conductor circuit 6 on the molding surface 1a of the male die 1 is transferred or embedded in the surface of the resin molded product, and is integrated into the resin molded product. Next, the injection molding die 3 was removed from the injection molding machine, and the injection molded product 7 was taken out from the injection molding die 3, thereby obtaining a three-dimensional wiring board as shown in FIG.

In the three-dimensional wiring board manufactured as described above, on one side of which was provided the desired conductor circuit 6, the conductor circuit 6 was embedded in a flat state with the surface of the molded product 7, and was firmly integrated. Furthermore, conductor circuit 6 with a radius of 1■ was not able to be bonded, and showed a stronger integrity than that of a copper foil wiring board.

In addition, in the above, on the injection molding surface of the male mold of the injection mold,
Although an insulating inorganic coating with a pattern opposite to the required conductor circuit was formed, an insulating inorganic coating with a pattern opposite to the required conductor circuit could also be formed on the injection molded surface of the female mold. A double-sided three-dimensional wiring board can also be used by forming insulating inorganic coatings with patterns opposite to the required conductor circuits on both injection molding surfaces of the mold and the female mold. However, the formation of the reverse pattern does not depend on the alumina layer,
For example, it may be formed of silica, titania, or the like. That is, it may be formed by a chemical vapor debostation method using an organic material such as titanium or silicon as a starting material.

Furthermore, the formation of the conductor circuit by electroplating on the injection molding surface of the mold on which the reverse pattern has been deposited may be performed by plating with a conductive metal other than copper. on the other hand,
The resin used for injection molding is not limited to the polycarbonate resin described above, and thermoplastic resins such as ABS resin, polypropylene resin, and vinyl chloride resin can also be used.

[Effects of the Invention] As described above, according to the present invention, a required conductor circuit is formed in advance by electroplating on the injection molding surface of at least one mold of an injection mold, and a required resin is placed in this mold. By injection molding, it is possible to easily obtain a three-dimensional wiring board in which the conductor circuit is transferred or embedded in a predetermined surface of a resin molded product. In other words, a three-dimensional wiring board in which the required conductor circuits are tightly integrated can be obtained at the same time through the injection molding process without requiring complicated operations and processes compared to conventional manufacturing methods for three-dimensional wiring boards. .

[Brief explanation of drawings]

1 to 6 are cross-sectional views schematically showing aspects of each step in the method for manufacturing a three-dimensional wiring board according to the present invention. 1...Male mold Ia...Male molding surface 2...Female mold 2a...Female molding surface 3...Injection Molding mold 4...Insulating inorganic coating (alumina layer) 4a...
... Reverse pattern 5 ... Plating resist layer 6 ... Conductor circuit 7 ... Molded product

Claims (1)

[Scope of Claims] A step of forming an insulating inorganic coating with a pattern opposite to a desired conductor circuit on the injection molding surface of at least one of the injection molds consisting of a male mold and a female mold; A step of electroplating the injection molding surface of the mold on which the insulating inorganic coating of the reverse pattern has been deposited to form a required conductor circuit, and using the mold with the conductor circuit deposited thereon for injection molding. A method for manufacturing a three-dimensional wiring board, comprising the steps of assembling it in a mold, injecting and molding a required resin into the mold, and transferring the conductive circuit onto a molding surface.