JP2849294B2 - Method and apparatus for manufacturing plastic three-dimensional circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a plastic three-dimensional circuit board having a circuit pattern of a thin metal layer on the surface, and a manufacturing apparatus for implementing the method.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a resist, a liquid resist is applied by a spraying method or a dipping method, a dry film is adhered, or an electroless film is formed after a plastic body having a circuit board shape is prepared using a molding die. A method of forming a thin metal layer on the surface of a molded article by plating and then coating the resist by electrodeposition is employed.

In the formation of a circuit pattern after the formation of a resist, a three-dimensional photolithographic mask having a shape conforming to the shape of a molded product to be a circuit substrate is separately manufactured, and a molded product of a circuit substrate having a resist formed on its surface is formed. And exposure and patterning. As the prior art,
For example, JP-A-54-27367, JP-A-1-29
There is a technique disclosed in JP-A-8792 and JP-A-2-251959.

[0004]

However, in the prior art, the molding of the circuit board using the mold and the molding of the resist are performed in separate steps. Therefore, it is difficult to make the formed resist follow the three-dimensional shape of the molded product, and the thickness of the resist tends to be uneven.

In the prior art, it is difficult to bring a three-dimensional photolithographic mask into close contact with a molded product to be a circuit board. In the case of poor adhesion, the irradiated light goes around and the circuit cannot be manufactured according to the target pattern.

The present invention has been made in view of the above circumstances, and an object of the present invention is to form a circuit board, form a resist layer, and perform patterning in a small number of steps. A plastic three-dimensional circuit that can easily follow the three-dimensional shape of the substrate, improve pattern position accuracy and pattern formation yield by exposure patterning, and can form the resist layer thinly and uniformly. An object of the present invention is to provide a method for manufacturing a substrate.

Still another object of the present invention is to provide an apparatus for manufacturing a plastic three-dimensional circuit board capable of reliably implementing the manufacturing method.

[0008]

In order to achieve the above object, in the method of the present invention, after forming a circuit board in a mold,
In the same molding die, the circuit forming surface of the circuit board, a resist solution is injected into a small gap between the mold surfaces of the molding die, a resist layer is formed on the circuit forming surface side of the circuit substrate, and in the same molding die. After exposing and patterning the resist layer, an integrated product of the circuit board and the resist layer, which is a molded product, is taken out of a mold, and then a circuit pattern conductive layer is formed.

In order to achieve the above object, according to the method of the present invention, all or a part of the resist layer formed in the molding die is cured in the same molding die, and then the molded circuit board is formed. An integrated product of the resist layer is taken out of the mold, and the resist layer is left in a pattern corresponding to the circuit, and then a circuit pattern conductive layer is formed.

Further, in order to achieve the above object, the apparatus of the present invention has a molding die, and a light shield corresponding to a circuit pattern on at least one surface, and the light shield is arranged on the cavity side, and A light-transmitting glass plate attached to a mold, a resist solution injecting means for injecting a resist solution into a circuit forming surface of a circuit board in the mold, and forming a resist layer; The resist layer formed on the circuit formation surface of the circuit board is exposed through the glass plate to form a circuit pattern.

[0011]

According to the method of the present invention, the molding of a circuit board, the formation of a resist layer on the circuit molding surface of the circuit board, and the patterning by exposure are performed using the same molding die and in the same mold clamping. I have. Therefore, the formation of the circuit board, the formation of the resist layer, and the patterning can be performed in a small number of steps, the resist layer can easily follow the three-dimensional shape of the circuit board, and the mold and the resist, which are photolithographic masks, can be formed. Since exposure can be performed in a state in which the layer is in close contact with the layer, it is possible to prevent light from wrapping around at the time of exposure, so that pattern position accuracy and pattern formation yield by exposure patterning can be improved.

Further, in the method of the present invention, a resist solution is injected into a minute gap between the circuit board and the mold surface of the mold in the mold,
A resist layer is formed on the circuit forming surface side of the circuit board. As a result, by controlling the pressure of the mold and the injection pressure of the resist solution, it is possible to form a thin and uniform resist layer, thereby producing a high-performance circuit having a small circuit line width and circuit line interval. Can be.

Further, in the method of the present invention, all or a part of the resist layer formed in the mold is cured in the same mold, taken out of the mold, and then the resist layer is patterned into a pattern corresponding to the circuit. Since the circuit pattern conductive layer is formed after being left in the shape, a high-precision three-dimensional circuit board can be manufactured.

The apparatus of the present invention includes a mold, a light-transmitting glass plate, a resist liquid injecting means, and a pattern forming means. Then, a molten resin is injected into the cavity of the mold, cooled and solidified to form a circuit board. Next, in the same mold, a resist solution is injected by a resist solution injecting means into a minute gap between the circuit forming surface of the circuit board and the mold surface of the mold. At this time, the injection pressure is controlled so that the resist solution spreads over the entire circuit forming surface of the circuit board, and a resist layer is formed on the circuit forming surface of the circuit board. Thereafter, the resist layer formed on the circuit forming surface of the circuit board formed in the mold is exposed through a glass plate by the pattern forming means. A light shield corresponding to a circuit pattern is provided on at least one surface of the glass plate, and the light shield is disposed on the cavity side and attached to a mold. As a result, by exposing the resist layer through the glass plate, the resist layer in contact with the exposed portion of the glass in the mold changes due to the exposure. This makes it possible to form a circuit pattern on the resist layer. continue,
The mold is opened, and the integrated product of the circuit board and the resist layer, which is a molded product, is taken out. Next, the removed molded article is washed, for example, to remove the uncured resist, exposing the conductive layer forming portion of the resist layer, and forming a circuit pattern conductive layer on the exposed portion. Therefore, according to the apparatus of the present invention, the method of the present invention can be reliably implemented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 shows an example of a manufacturing apparatus for carrying out the method of the present invention, and FIG. 2 shows a glass plate attached to the manufacturing apparatus. The manufacturing apparatus shown in FIG. 1 includes an injection unit 1 of a molding resin material, a lower mold clamping plate 2, an upper mold clamping plate 3, a molding die 5, and a temperature control device (not shown) for the molding die 5. And a UV light source lamp 14 constituting a pattern forming means. In this embodiment, a circuit pattern is formed only on one surface (upper surface) of a circuit board to be formed. I have.

A hydraulic machine 4 for mold clamping is connected to the upper mold clamping plate 3.

The molding die 5 includes a metal core die 6, a metal cavity die 7, a glass plate 8 serving as a photolithographic mask, and a cavity 10 surrounded by these members. It is configured to have. As shown in FIG. 2, a light shield 9 corresponding to a circuit pattern to be formed is provided on one surface of the glass plate 8. The light shielding body 9 forms a groove having a minute depth by etching on the surface of the glass plate 8 in the same pattern as the pattern that will eventually become a circuit, and then deposits aluminum on the surface of the glass plate 8, The surface is polished, the surface of the glass plate 8 and the surface of the aluminum light shield 9 are finished to be flush with each other, and the aluminum light shield 9 is embedded in the groove. As shown in FIG. 1, the glass plate 8 having the light shield 9 is provided with the light shield 9 on the cavity 10 side, that is, on the circuit forming surface side of the formed circuit board. And is attached to the cavity mold part 7.

As shown in FIG. 1, the resist liquid injection means has a resist liquid injector 11, a resist liquid supply pipe 12, and a resist liquid inlet 13. The resist liquid injector 11 is configured to pressurize and send the resist liquid by a piston. The resist liquid inlet 13 is provided so as to inject a resist liquid into a minute gap between the circuit forming surface of the molded circuit board and the surface of the glass plate 8 on which the light shield 9 is provided. Has become.

The ultraviolet light source lamp 14 is disposed on the side of the glass plate 8 opposite to the side on which the light shield 9 is provided, is attached to the cavity mold 7, and passes through the glass plate 8 to the resist layer. Is illuminated.

Next, FIG. 3 to FIG. 9 show an example of the method of the present invention carried out by using the manufacturing apparatus in the order of steps, and FIG. 10 shows a finished product. In the manufacturing method shown in these figures, a molten resin injection step, a resist liquid injection step, an ultraviolet irradiation / exposure patterning step, a molded article removal / cleaning step, a non-resist part roughening step, and a resist layer A peeling step;
Through the step of forming a circuit pattern conductive layer, a plastic three-dimensional circuit board is manufactured.

(1): Injection step of molten resin In this step, the molding die 5 is clamped by the lower clamping plate 2, the upper clamping plate 3 and the hydraulic machine 4 shown in FIG. As shown in FIG. 3, the molten resin is injected into the cavity 10 of the molding die 5 from the molding resin injection unit 1. As the molding resin material, for example, a mineral-filled polyphenylene sulfide (PPS) thermoplastic resin is used. Next, the molten material injected into the cavity 10 is cooled and solidified by a temperature control device (not shown) to form a circuit board 15.

(2): Resist Liquid Injection Step In this step, after the circuit board 15 is formed, the same molding die 5 is used and the circuit board 15 is closed as shown in FIG. A resist solution 17 is injected into a minute gap 16 between the surface on which the light shield 9 of the glass plate 8 which is the mold surface of the mold 5 and the mold surface is provided. As the resist liquid 17, a negative type liquid in which an exposed portion is cured is used. Further, the resist liquid 17 is supplied from the resist liquid supply pipe 12 to the resist liquid inlet 13,
The resist solution is injected into the gap 16 through the resist solution inlet 13, and the injection pressure of the resist solution 17 is controlled by the piston of the resist solution injector 11, so that the resist solution 17 in the gap 16 is formed on the circuit forming surface of the circuit board 15. A resist layer 18 is formed so as to have a uniform thickness over the entire surface.

(3): Ultraviolet irradiation / exposure patterning step In this step, the same molding die 5 is used, and the ultraviolet light source lamp 14 is turned on while the mold is clamped, and as shown in FIG. 8, the resist layer 18 on the circuit board 15 is irradiated with ultraviolet rays. As described above, when the negative resist layer 18 is irradiated with ultraviolet rays, the exposed portion of the resist layer 18 of the glass plate 8 is hardened as shown in FIG. Portions of layer 18 remain softened. Therefore, the cured portion 19 of the pattern corresponding to the circuit pattern is formed on the resist layer 18 by the action of the light shield 9 corresponding to the circuit pattern.

(4) Mold Removal / Cleaning Step In this step, the mold 5 is opened, and the integrated product of the circuit board 15 and the resist layer 18 as a molded product is removed. Next, the removed molded article is washed, and the uncured portion of the resist layer 18 is removed as shown in FIG. By this cleaning, the conductive layer forming portion on the circuit forming surface of the circuit board 15 is exposed.

(5) Step of Roughening Non-Resist Part In this step, as described above, after exposing the conductive part of the resist layer 18, the integrated product of the circuit board 15 and the cured part 19 of the resist layer is removed. The substrate is immersed in an alkaline etching solution to roughen the conductive layer forming portion of the circuit board 15 as shown in FIG. The roughened conductive layer forming portion is indicated by reference numeral 20 in FIG.

(6): Step of stripping the resist layer In this step, after the conductive layer forming portion of the circuit board 15 is roughened, the hardened portion 19 of the remaining resist layer 18 is stripped, as can be seen from FIG. To remove.

(7): Step of Forming Circuit Pattern Conductive Layer In this step, surface activation, nucleation and electroless plating are performed on the roughened conductive layer forming portion 20 of the circuit board 15 as described above. As a result, the circuit pattern conductive layer 2 is formed in the conductive layer forming portion 20 as shown in FIG.
Form one. In this embodiment, a thick circuit pattern conductive layer 21 is formed by electroless plating due to a full additive method. In addition, since plating nuclei do not easily adhere to unroughened parts after the resist layer 18 is peeled off, the occurrence of metal deposition by electroless plating is small, and even if there is metal deposition, circuit Since the adhesion to the substrate 15 is extremely small, it is removed in the process of removing the adhered metal by the cleaning process after the electroless plating process.

Through the above steps (1) to (7), a plastic three-dimensional circuit board having the circuit pattern conductive layer 21 formed on the circuit forming surface of the circuit board 15 as a completed product shown in FIG. Can be manufactured.

Next, various other embodiments of the present invention will be described.

(A): In the present invention, the surface of the circuit board 15
The present invention is not limited to the embodiment in which the circuit pattern conductive layer 21 is formed on one surface of the back surface, and can be applied to a so-called double-sided substrate in which the circuit pattern conductive layer 21 is formed on both front and back surfaces of the circuit board 15. The present invention can be applied to a case where the circuit pattern conductive layer 21 is formed on the end surface (vertical surface) of the circuit board 15 in addition to the back surface. When the circuit pattern conductive layer 21 is formed on the plurality of surfaces, the glass plate 8 having the light shield 9, the resist solution inlet 13 of the resist solution injecting means, It is assumed that an ultraviolet light source lamp 14 and the like as circuit pattern forming means are provided.

(B): The material for forming the light shield 9 provided on the glass plate 8 is not particularly limited. However, if metal is used, the thickness of the light shield 9 is reduced to increase the light blocking property. This is advantageous because it can be performed.

(C): The number of the resist liquid inlets 13 is not limited to one for one circuit formation surface of the circuit board 15 but may be plural.

(D): The resist layer 18 is not limited to the one formed on the entire surface of the circuit board 15 on which the circuit is formed, and it is sufficient to form the cured portion 19 of the resist layer 18 in a portion corresponding to the circuit pattern. May be partially formed on the circuit forming surface of the circuit board 18.

(E): As the resist liquid, either a negative type in which the exposed part is cured or a positive type in which the exposed part is solubilized can be used. Negative types that do not require exposure are more advantageous.

(F): The light source used for exposing the resist layer 18 is not limited to the ultraviolet light source lamp 14, and a light source that generates visible light or laser light can be used.

[0036]

As described above, according to the method of the present invention, after a circuit board is formed in a molding die, a small gap between the circuit forming surface of the circuit board and the die surface of the molding die is formed in the same molding die. After injecting a resist solution, forming a resist layer on the circuit forming surface side of the circuit board, exposing the resist layer to light in the same mold, and performing patterning. The integrated product is taken out of the mold, and subsequently the circuit pattern conductive layer is formed. Therefore, by controlling the pressure of the mold and the injection pressure of the resist solution, the thickness of the resist layer is reduced to, for example, 15 μm or less. Can be formed, and the film thickness can be formed uniformly.
As a result, there is an effect that a three-dimensional circuit board having a high-performance circuit having a small circuit line width of, for example, 100 μm and a small circuit line interval, that is, a small circuit pattern pitch can be produced.

Further, in the method of the present invention, all or a part of the resist layer formed in the mold is cured in the same mold, taken out of the mold, and then the resist layer is patterned into a pattern corresponding to the circuit. Since the circuit pattern conductive layer is formed after being left in the shape, there is an effect that a highly accurate three-dimensional circuit board can be manufactured.

Further, the apparatus of the present invention has a molding die and a light shield corresponding to a circuit pattern on at least one surface, and the light shield is disposed on the cavity side and is attached to the molding die. A transparent glass plate, a resist solution injecting means for injecting a resist solution into a circuit forming surface of a circuit board in the mold, and forming a resist layer, and a circuit forming surface of the circuit board molded in the mold. Since the formed resist layer is provided with pattern forming means for exposing the formed resist layer through the glass plate to form a circuit pattern, there is an effect that the method of the present invention can be surely implemented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a manufacturing apparatus for performing a method of the present invention.

FIG. 2 is a perspective view showing an example of a glass plate having a light shield used in the manufacturing apparatus shown in FIG.

FIG. 3 is an explanatory view of a molten resin injection step in the method of the present invention.

FIG. 4 is an explanatory view of a resist liquid injecting step following FIG. 3;

FIG. 5 is an explanatory view of an ultraviolet irradiation / exposure patterning step following FIG. 4;

FIG. 6 is an explanatory diagram of a molded article taking-out / cleaning step following FIG. 5;

FIG. 7 is an explanatory view of the step of roughening the non-resist part following FIG. 6;

FIG. 8 is an explanatory view of the resist layer removing step following FIG. 7;

FIG. 9 is an explanatory view of the step of forming the circuit pattern conductive layer following FIG. 8;

FIG. 10 is a perspective view of a completed plastic three-dimensional circuit board.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Injection unit of molding resin material 2 Lower mold clamping plate 3 Upper mold clamping plate 5 Mold 6 Mold core 7 Mold cavity 8 Glass plate 9 Light shield 10 Cavity 11 Resist liquid injector 12 Resist liquid Supply pipe 13 Resist liquid inlet 14 Ultraviolet light source lamp 15 Circuit board 16 Micro gap between circuit forming surface of circuit board and mold surface of mold 17 Resist liquid 18 Resist layer 19 Hardened portion of resist layer 20 Roughened conductive layer Forming part 21 Circuit pattern conductive layer

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI // B29L 31:34

Claims (3)

(57) [Claims] After a circuit board is molded in a mold, a resist solution is injected into a small gap between a circuit forming surface of the circuit board and a mold surface of the mold in the same mold to form a circuit board. After forming a resist layer on the circuit forming surface side, in the same mold, exposed to the resist layer, after patterning,
A method for producing a plastic three-dimensional circuit board, comprising taking out a molded article of a circuit board and a resist layer from a mold and subsequently forming a circuit pattern conductive layer. 2. After all or a part of the resist layer formed in the mold is cured in the same mold, an integrated product of the circuit board and the resist layer, which is a molded product, is taken out from the mold. 2. The method according to claim 1, wherein the circuit pattern conductive layer is formed after the resist layer is left in a pattern corresponding to the circuit. 3. A light-transmitting glass having a mold and a light shield corresponding to a circuit pattern on at least one surface, and the light shield is disposed on the cavity side and attached to the mold. A plate, a resist liquid injecting means for injecting a resist liquid into the circuit forming surface of the circuit board in the molding die to form a resist layer, and a resist formed on the circuit forming surface of the circuit substrate molded in the molding die Pattern forming means for exposing a layer to light through the glass plate to form a circuit pattern. A manufacturing apparatus for a plastic three-dimensional circuit board, comprising: