JP4426690B2 - 3D circuit board manufacturing method and 3D circuit board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a three-dimensional circuit board such as a dielectric antenna used in a mobile communication device or a GPS (Global Positioning System) device of a mobile phone, and a three-dimensional circuit substrate manufactured by the manufacturing method.
[0002]
[Prior art]
Conventionally, as a method of manufacturing a three-dimensional circuit board such as a dielectric antenna, a predetermined shape of a dielectric substrate is formed from a dielectric material, and the predetermined pattern of the surface of the dielectric substrate formed into the predetermined shape is formed. A resin mask is integrally formed on this dielectric substrate so that the surface portion where the conductive layer is to be formed is exposed and the surface portion other than this portion is covered, and metal particles are attached to the surface to be electrolessly plated. A conductive layer is formed by electroless plating on the surface of the resin mask and on the entire surface of the dielectric substrate exposed from the resin mask, and the plated dielectric substrate and the resin The resin mask is removed from the integral product with the mask, and a conductor layer having a predetermined pattern is formed on the surface of the dielectric substrate (for example, Japanese Patent Laid-Open No. 11-17442).
[0003]
[Problems to be solved by the invention]
However, in order to obtain an adhesive strength sufficient to prevent the etching solution or catalyst solution from penetrating into the adhesive interface between the dielectric substrate and the resin mask, the dielectric substrate and the resin mask are compatible with each other. Some of them were selected and applied. Further, after the conductive layer is formed by electroless plating, that is, after the conductive layer is formed on the surface of the resin mask and the entire surface of the dielectric substrate exposed from the resin mask, the resin mask is removed. Therefore, when removing this resin mask, the conductive layer on the surface of the resin mask and the conductor layer of the dielectric substrate that are continuously connected to each other are forcedly peeled so that the periphery of the conductor layer of the dielectric substrate is uneven. The shape, that is, a zigzag state, a residue that may hinder the use of the dielectric substrate, or a wrinkle. For this reason, the area of the dielectric antenna is not as designed, and the function as an antenna is reduced.
[0004]
Accordingly, an object of the present invention is a manufacturing method of a three-dimensional circuit board capable of easily and promptly removing a resin mask from a dielectric substrate, and a manufacturing method thereof, with a clear outline around the conductor layer of the conductor substrate. It is to provide a three-dimensional circuit board.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a first step of forming the dielectric substrate having the predetermined shape from a synthetic resin material, and a conductor layer having the predetermined pattern is formed on the surface of the dielectric substrate. A second step of exposing a surface portion to be exposed and forming a resin mask on the dielectric substrate so as to cover other surface portions; and the dielectric substrate exposed from the resin mask and the resin mask A third step of roughening the entire surface, a fourth step of applying a catalyst for electroless plating to the roughened whole surface, and removing the resin mask from the dielectric substrate. A fifth step and a fifth step of forming a conductive layer of a predetermined pattern on the surface of the dielectric substrate by electroless plating, wherein the dielectric substrate and the resin mask material are mutually Weakly compatible It is in place.
[0006]
Therefore, the present invention is characterized in that the conductor base material formed in the first step and the resin mask material formed in the second step are weakly compatible with each other in order to obtain an appropriate adhesive strength. By the way. This weak compatibility is an intermediate between compatibility and incompatibility. Specifically, when the interface between the dielectric substrate and the resin mask is mechanically peeled off, the surface of the dielectric substrate is hindered in use. In this state, no residue remains, soot remains, and the etching solution, catalyst solution, or plating solution in the wet process is welded at a temperature within a range that can be prevented from penetrating into the interface.
[0007]
Furthermore, another feature is that the sixth conductive layer is formed after removing the resin mask in the fifth step.
[0008]
Synthetic resin as a material for the dielectric substrate is excellent in heat resistance and strength. For example, it is molded by injecting a plating grade thermoplastic liquid crystal polymer into a cavity with the mold closed. This thermoplastic liquid crystal polymer is a thermoplastic aromatic polyester resin (LCP), which uses a plating grade C810 of “Vectra” (trade name, manufactured by Polyplastics Co., Ltd.).
[0009]
In addition, as a synthetic resin for the material of the dielectric substrate 1, heat such as polyphenylene sulfide (PPS), polyphenine ether (PPE), polyetherimide (PEI), polybutylene terephthalate (PBT), syndiotactic polystyrene (SPS), etc. A plastic resin can be selectively applied. A dielectric substrate which is a cubic primary substrate of a predetermined shape is formed by injection molding such a synthetic resin.
[0010]
Next, the synthetic resin of the resin mask material of the secondary molded product is an elastomer that can be easily bent. As this elastomer, “Hytrel # SB704, a product name made by Toray DuPont, a thermoplastic polyester elastomer” is used. "It was used. This is elastic at room temperature.
[0011]
In addition, there are styrenic elastomers such as styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene copolymer, and styrene-ethylene-butylene-styrene block copolymer.
[0012]
These elastomers may be used alone or in combination of two or more. You may mix and use a thermoplastic resin as long as the elasticity which an elastomer has is not impaired.
[0013]
In order to adjust dimensional accuracy and hardness, an inorganic filler such as talc, bentonite, mica, wollastonite, glass filler, or the like may be added to the resin material for the resin mask 2 in a composite manner. Furthermore, an incompatible elastomer may be appropriately mixed in a compatible elastomer such as a styrene-based elastomer to improve weak compatibility.
[0014]
According to a second aspect of the present invention, there is provided a first step of forming the dielectric substrate having the predetermined shape from a synthetic resin material, and a conductor layer having the predetermined pattern is formed on the surface of the dielectric substrate. A second step of exposing a surface portion to be exposed and forming a resin mask on the dielectric substrate so as to cover other surface portions; the resin mask and the dielectric substrate exposed from the resin mask; A third step of roughening the entire surface of the substrate, a fourth step of applying a catalyst for electroless plating to the roughened entire surface, and a roughening treatment of the dielectric substrate. A fifth step of forming a conductive layer on the entire surface of the surface and the resin mask by electroless plating, and a sixth step of removing the resin mask from the dielectric substrate, and further comprising: The material for the resin mask is There is to be of Yowasho soluble in. The material of the invention described in claim 1 is selectively applied to the dielectric substrate and the resin mask.
[0015]
The feature of the present invention is that the material of the dielectric substrate and the resin mask are weakly compatible with each other. This weak compatibility is intermediate between compatible and incompatible as described above. When mechanically peeling the interface of the resin mask from the body substrate, there is no residue, wrinkles, and no etching solution, catalyst solution and chemical plating solution in the wet process on the surface of the dielectric substrate. A state where welding is performed at a temperature within a range where penetration into the interface can be prevented.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a method of manufacturing a three-dimensional circuit board according to the present invention will be described with reference to the drawings. First, the first embodiment is shown in FIGS. As shown in FIG. 1A, the first step is to form a dielectric substrate 1 that is a primary molded product. The synthetic resin of the dielectric substrate material is excellent in heat resistance and strength. In the closed state, a plating grade thermoplastic liquid crystal polymer is injected into the cavity and molded. This thermoplastic liquid crystal polymer is a thermoplastic aromatic polyester resin, which uses "Vectra" (trade name, manufactured by Polyplastics Co., Ltd.), plating grade C810, which is thermoplastic while being solder-resistant. And has performance as a molded circuit component. Therefore, the dielectric substrate 1 which is a primary substrate of a cube having a predetermined shape is formed by injection molding a synthetic resin material.
[0017]
Next, in the second step, as shown in FIG. 1B, after the first step, a conductor layer 4 (see FIG. 1F) having a predetermined pattern is formed on the surface of the dielectric substrate 1. The resin mask 2 is formed on the dielectric substrate so that the surface portion to be exposed is exposed and the other surface portion is covered. The material of the resin mask 2 is an elastomer that can be easily bent. This elastomer has elasticity at room temperature, and is a thermoplastic polyester elastomer, “Hytrel # SB704, a product name manufactured by Toray DuPont”. It was used.
[0018]
As described above, since “Vectra” is used as the material of the dielectric substrate 1 and “Hytrel # SB704” is used as the material of the resin mask 2, the dielectric substrate 1 and the resin mask 2 are weakly phased. The adhesive strength in the range of solubility is obtained, so that the removal operation of the resin mask 2 which is a fifth process described later is simplified. The molding conditions of the resin mask 2 were as follows: in a molding machine (Model: TI30G2 manufactured by Toyo Machine Metal Co., Ltd.), cylinder temperature: 230 ° C., injection pressure: 717 kg / cm ² , molding cycle: 25 seconds, mold temperature: 40 It is set to ° C.
[0019]
Next, the chemical etching step of the third step will be described with reference to FIG. 1C. This etching-treated surface 3 is the entire surface of the dielectric substrate 1 exposed from the resin mask 2 and the resin mask. Is roughened. As an example of this etching treatment, an alkaline aqueous solution in which caustic soda or caustic potash is dissolved at a predetermined concentration, for example, 45 wt% is heated to a predetermined temperature, for example, 50 to 90 ° C., and the dielectric substrate 1 of the primary molded product, The resin mask 2 is immersed for a predetermined time, for example, 30 minutes. This etching process roughens the entire surface. In this step, the interface where the dielectric substrate 1 and the resin mask 2 are in contact with each other is sufficiently prevented from penetrating into the interface due to weakly compatible adhesive strength.
[0020]
Therefore, the fourth step will be described with reference to FIG. 1D. In this step, a catalyst-giving surface 31 is formed by imparting (giving) a catalyst such as palladium or gold to the roughened processing surface 3. 1C is immersed in a mixed catalyst solution of tin, palladium, and activated with an acid such as hydrochloric acid or sulfuric acid to deposit palladium on the surface. Alternatively, a relatively strong reducing agent such as stannous chloride is adsorbed on the surface and immersed in a catalyst solution containing a noble metal ion such as gold to deposit gold on the surface. What is necessary is just to immerse the temperature of a liquid at 15-23 degreeC for 5 minute (s). The roughened treatment surface 3 becomes a surface 31 provided with a catalyst. Also in this step, the interface where the dielectric substrate 1 and the resin mask 2 are in contact with each other does not permeate the catalyst solution due to weakly compatible adhesive strength.
[0021]
Next, the fifth step will be described with reference to FIG. 1 (E). In this step, the dielectric substrate 1 and the resin mask 2 to which the catalyst has been applied by etching are dried, and then the resin mask 2 is removed from the dielectric substrate 1. This is a step of removing, which can be performed manually, but an apparatus for removing the resin mask 2 may be used in order to facilitate this removal operation. In addition, since the material of the resin mask 2 and the material of the dielectric substrate 1 are selected from weakly compatible synthetic resins, the adhesive strength between compatible resins is weaker. Therefore, the removal operation of the resin mask 2 is simplified as described above.
[0022]
Finally, the sixth step will be described with reference to FIG. 1 (F). The conductive layer 4 is formed on the surface of the dielectric substrate 1 on the etching treatment surface 3 having a predetermined pattern by electroless plating. The three-dimensional circuit board is completed through the above steps.
[0023]
Next, another embodiment of the present invention will be described with reference to FIGS. 2A to 2E. As shown in FIG. 2A, the first step is a dielectric that is a primary molded product. The body substrate 1 is molded, and the synthetic resin of the dielectric base material is formed by injecting and molding the same plating grade thermoplastic liquid crystal polymer as in the first embodiment. The thermoplastic liquid crystal polymer Uses a plating grade C810 of “Vectra” (trade name, manufactured by Polyplastics Co., Ltd.), which is a thermoplastic aromatic polyester resin. As described above, the liquid crystal polymer is thermoplastic but has solder mounting heat resistance. Accordingly, a cubic dielectric substrate 1 having a predetermined shape is formed by injection molding a synthetic resin material.
[0024]
Next, in the second step, as shown in FIG. 2B, after the first step, a conductor layer 4 (see FIG. 2E) having a predetermined pattern is formed on the surface of the dielectric substrate 1. The resin mask 2 is formed on the dielectric substrate so that the surface portion to be exposed is exposed and the other surface portion is covered. The material of the resin mask 2 is an elastomer that can be easily bent. The elastomer has elasticity at room temperature, and is a polyester-based elastomer, “trade name made by Hytrel # SB704 Toray DuPont”. use.
[0025]
The resin mask 2 is a thermoplastic elastomer and needs to be weakly compatible with the dielectric substrate 1. Therefore, in the state of FIG. 2B, the chemical etching solution and electroless (chemical) plating solution to be performed thereafter do not penetrate into the interface between the dielectric substrate 1 and the resin mask 2, and the resin mask. The removal of 2, i.e. mechanical peeling, can also be carried out very easily and quickly.
[0026]
Next, the chemical etching step of the third step will be described with reference to FIG. 2C. This etching processing surface 3 is the resin mask 2 and the entire surface of the dielectric substrate 1 exposed from the resin mask. Is roughened. As an example of this etching treatment, as in the above-described embodiment, an alkaline aqueous solution in which caustic soda or caustic potash is dissolved at a predetermined concentration, for example, 45 wt%, is heated to a predetermined temperature, for example, 50 to 90 ° C. The body base 1 and the resin mask 2 of the secondary molded product are immersed for a predetermined time, for example, 30 minutes. This etching process roughens the entire surface. In this process, the interface where the dielectric substrate 1 and the resin mask 2 are in contact with each other does not penetrate into the interface due to weakly compatible adhesive strength.
[0027]
Accordingly, the fourth step will be described with reference to FIG. 2D. In this step, a catalyst made of palladium, gold, or the like is imparted (given) to the roughened treated surface 3, which is the same as the embodiment described above. The same. That is, after the molded product shown in FIG. 2C is immersed in a mixed catalyst solution of tin and palladium, it is activated with an acid such as hydrochloric acid or sulfuric acid to deposit palladium on the surface. Alternatively, a relatively strong reducing agent such as stannous chloride is adsorbed on the surface and immersed in a catalyst solution containing a noble metal ion such as gold to deposit gold on the surface. What is necessary is just to immerse the temperature of a liquid at 15-23 degreeC for 5 minute (s). The roughened treatment surface 3 becomes a surface 31 provided with a catalyst. Also in this step, the interface where the dielectric substrate 1 and the resin mask 2 are in contact with each other does not permeate the catalyst solution due to weakly compatible adhesive strength.
[0028]
As described above, the first process to the fourth process in this embodiment are substantially the same as the first process to the fourth process in the above-described embodiment, and the same reference numerals are assigned to the same drawings. is doing. However, in the above-described embodiment, the resin mask 2 in the third and fourth steps and the entire surface of the dielectric substrate 1 exposed from the resin mask are roughened, and further provided with a catalyst. Although the mask is removed, in this embodiment, as a fifth step, the conductive layer 4 is formed on the etched surface 3 of the dielectric substrate 1 and the entire surface of the resin mask 2 as shown in FIG. Is formed by electroless plating, and then the resin mask is removed.
[0029]
That is, finally, in the fifth step, the resin mask 2 is removed from the dielectric substrate 1 together with the conductive layer 4 on the surface of the mask as shown in FIG. 2 (F). Since the materials of the dielectric substrate 1 and the resin mask 2 are weakly compatible with each other, when the interface of the resin mask is peeled off in order to remove the resin mask, the peeling operation is performed easily and promptly. Furthermore, no residue or wrinkles that hinder the use are left on the surface of the dielectric substrate 1.
[0030]
【The invention's effect】
According to the present invention, since the conductor layer formed by electroless plating has an accurate contour as designed, for example, when a dielectric antenna is manufactured, the function as an antenna is sufficiently exhibited. When the interface of the resin mask is peeled off without the chemical etching solution or electroless plating solution penetrating between the mask and the mask, the peeling work can be easily and promptly performed. There is no residue or flaws left on the surface that would hinder use.
[Brief description of the drawings]
FIGS. 1A, 1B, 1C, 1D and 1E are schematic views showing step by step the respective production steps according to the first embodiment of the present invention.
FIGS. 2 (A), (B), (C), (D) and (E) are schematic views showing steps of manufacturing according to the second embodiment of the present invention in stages.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Dielectric base | substrate 2 Resin mask 3 Etching surface 31 The surface to which the catalyst was provided 4 Conductive layer

Claims (2)

In a method for manufacturing a three-dimensional circuit board, in which a conductor layer having a predetermined pattern made of a conductive material is formed on the surface of a dielectric substrate having a predetermined shape made of a synthetic resin material,
Forming the dielectric substrate of the predetermined shape with a synthetic resin material;
A step of exposing a surface portion of the surface of the dielectric substrate on which the conductor layer of the predetermined pattern is to be formed and forming a resin mask on the dielectric substrate so as to cover the other surface portion;
A step of roughening the resin mask and the entire surface of the dielectric substrate exposed from the resin mask;
Providing a catalyst for electroless plating on the entire surface subjected to the roughening treatment,
Forming a conductive layer by electroless plating on the roughened surface of the dielectric substrate and the entire surface of the resin mask;
And removing the resin mask from the dielectric substrate,
The material of the dielectric substrate and the resin mask der those mutually Yowasho soluble,
The method of manufacturing a three-dimensional circuit board, wherein the dielectric substrate is a thermoplastic liquid crystal polymer, and the resin mask is a thermoplastic polyester elastomer having elasticity at room temperature . A three-dimensional circuit board manufactured by the manufacturing method according to claim 1 .

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