JPH0785512B2 - Method for manufacturing single-sided flexible circuit board - Google Patents

Description

The present invention relates to a method for manufacturing a single-sided flexible circuit board, and in particular, the thickness of an insulating base material thereof is set to an arbitrary value by an ablation process by excimer laser irradiation. The present invention relates to a suitable manufacturing method for a single-sided flexible circuit board which is remarkably highly flexible by being processed into.

“Prior art and its problems” For this type of single-sided flexible circuit board, for example, a typical material such as a so-called single-sided flexible copper clad laminate is prepared, and photo etching is performed on the copper foil side. It was manufactured by performing a process to form a required circuit wiring pattern.

Therefore, in the single-sided flexible circuit board manufactured by such a conventional method, the thickness of the insulating base material is predetermined depending on the material such as the copper clad laminate to be used. Accordingly, the insulating base material also needs to be selected in advance. However, when extremely flexible products are required, the insulation and insulation processing are difficult due to the difficulty of processing such as wrinkles or damage during handling in addition to the exposure and development processing steps and the photoetching processing step. There is a disadvantage that a base material having a certain thickness or less cannot be used. Therefore, in this type of flexible circuit board, there is a problem that it is not possible to suitably meet the specifications that require extremely high flexibility.

"Object and Structure of the Invention" In the present invention, therefore, the entire thickness of the insulating base material in a single-sided flexible circuit board is arbitrarily irradiated by irradiating an excimer laser with an ablation process. For a single-sided flexible circuit board that can be formed thinly and thus configured to have a thickness that cannot be achieved by conventional materials to remarkably increase the flexibility of this type of flexible circuit board. It provides a manufacturing method.

As a basic manufacturing method therefor, a flexible conductive foil-clad laminated sheet having a conductive foil coated on one surface of a flexible insulating base material is prepared, and the conductive foil is subjected to an etching treatment. After forming a required circuit wiring pattern, an excimer laser is irradiated from the outer surface side of the insulating base material to uniformly ablate the thickness of the insulating base material to a predetermined thin thickness. A method of manufacturing a mold flexible circuit board is provided.

In such a manufacturing method, a metal mask layer is formed on the other surface of the insulating base material, and the metal mask layer is adapted to the outer shape of the product during the etching process for forming the circuit wiring pattern. After forming the slot exposing the material portion, the location of the slot is ablated by excimer laser irradiation to remove the insulating base material portion at the location of the slot to a predetermined depth, and then the metal When the mask layer is removed, an excimer laser is irradiated from the outer surface side of the insulating base material to uniformly ablate the insulating base material to a predetermined depth to form a predetermined thickness and to form the groove. A step of forming a slot for separating the outer shape of the product can be included in the hole portion. A flexible double-sided conductive foil-clad laminate can be used as the material having the conductive foil on one surface of the insulating base material and the metal mask layer on the other surface.

[Examples] Hereinafter, the present invention will be described in more detail with reference to an illustrated example.

FIGS. 1 and 2 are conceptual manufacturing process diagrams of a single-sided flexible circuit board according to the present invention. As shown in FIG. A conductive foil-clad laminate is prepared, and one of the conductive foils of the flexible insulating base material 1 is subjected to photo-etching to form a required circuit wiring pattern 3, and the other conductive foil. Is used as the metal mask layer 2. The metal mask layer 2 is formed with a groove hole 2A that matches the outer shape of the product during the etching process. Since the groove 2A is formed so as to expose the insulating base material 1, by irradiating the portion of the groove 2A with the excimer laser beam A1 as shown in the figure, the corresponding portion of the insulating base material 1 is exposed. Groove with predetermined depth
Photoablation processing is performed so as to form 1A.

Therefore, at the stage where the unnecessary metal mask layer 2 is appropriately removed after the above-mentioned processing steps, as shown in FIG. 2, the excimer laser light A2 is uniformly irradiated from the outer surface to the entire surface of the insulating base material 1. The slot 1A as shown by the phantom line in FIG.
When the ablation process is performed up to the depth of, a groove 4A for separation suitable for the outer shape of the product is formed at the position of the groove 1A, and a thin insulating base material 4 having a reduced thickness is formed. You can Here, since it is possible to form a surface protective layer made of an appropriate film member on the surface on the side of the circuit wiring pattern 3 before the removal processing of the metal mask layer 2, the removal processing step of the metal mask layer 2 is performed. Can use an etching technique.

In the above manufacturing method, without providing the metal mask layer 2 on the other surface of the insulating base material 1, first, using a light shielding mask means or the like from the outer surface side of the insulating base material 1, a groove hole having a predetermined depth is formed. A method of immediately forming 1A on the insulating base material 1 can also be adopted, and in this case, a general material such as a flexible single-sided copper clad laminated board can be used as the laminated board material. As the structure of such a double-sided or single-sided conductive foil-clad laminate, it is possible to use both the one in which an adhesive layer is interposed between the insulating base material and the conductive foil or the one without an adhesive. it can. Further, the single-sided flexible circuit board manufactured by the above-mentioned method exhibits extremely high flexibility, but on the other hand, there is a possibility that wrinkles or damage may be easily given in handling before mounting on a device. Because there is
On the outer surface of the thin photoablation-processed insulating base material 4, an appropriate pressure-sensitive adhesive for mounting the device is provided as necessary in the final step, or a release sheet is provided on the adhesive surface or alone. It is also possible to provide a temporary protective sheet to temporarily maintain the mechanical strength of the single-sided flexible circuit board until it is mounted on a device.

[Advantages of the Invention] As described above, the present invention is suitable for specifications that cannot be achieved by the conventional method because the thickness of the insulating base material for forming the circuit wiring pattern can be formed to an arbitrary thickness by the photoablation process using the excimer laser. A single-sided flexible circuit board having high flexibility can be configured.

As a material necessary for manufacturing such a highly flexible circuit board, an ordinary single-sided or double-sided conductive foil-clad laminate can be used, and therefore, it is necessary to form a circuit wiring pattern. The exposure / development processing step and the photo-etching step can be surely processed in the same easy-to-handle state as in the conventional case.

[Brief description of drawings]

FIG. 1 shows that, according to one embodiment of the present invention, a circuit wiring pattern is formed on one surface of a flexible insulating base material and a groove corresponding to the outer shape of a product is etched on the metal mask layer side provided on the other surface. FIG. 2 is a process explanatory diagram in a state where the photoablation process is performed, and FIG. 2 is a similar process explanatory diagram in a state in which the insulating base material is photoablated to a predetermined thickness after the metal mask layer is removed. 1: Insulating base material 1A: Groove with a predetermined depth 2: Metal mask layer 2A: Metal mask layer groove 3: Circuit wiring pattern 4: Thin insulating base material 4A: Separation groove A1: Excimer laser light A2 : Excimer laser light

Claims (3)

[Claims] 1. A flexible conductive foil-clad laminate having a conductive foil coated on one surface of a flexible insulating base material is prepared, and the conductive foil is etched to form a desired circuit wiring pattern. After formation, a single-sided flexible circuit board characterized by irradiating an excimer laser from the outer surface side of the insulating base material to uniformly ablate the insulating base material to a predetermined thin thickness. Manufacturing method. 2. A metal mask layer is formed on the other surface of the insulating base material, and the metal mask layer is made to conform to the outer shape of the product during the etching process for forming the circuit wiring pattern. After forming the groove to be exposed, the portion of the groove is subjected to ablation by excimer laser irradiation to remove the insulating base material portion at the portion of the groove to a predetermined depth, and then the metal mask layer is formed. When the insulating base material is removed, an excimer laser is irradiated from the outer surface side of the insulating base material to uniformly ablate the thickness of the insulating base material to the predetermined depth to form a predetermined thickness, and the groove portion. The step of forming a groove for separating the outer shape of the product in the step (1).
Method for manufacturing single-sided flexible circuit board. 3. A flexible double-sided conductive foil-clad laminate is used as the material having a conductive foil on one surface of the insulating base material and a metal mask layer on the other surface. 2) A method for manufacturing a single-sided flexible circuit board.