Patent Application
20170347444
The instant disclosure relates to a manufacturing method of circuit board; in particular, to a manufacturing method of curved circuit board, and an electronic product using the curved circuit board.
Population densities of printed circuit boards have increased with the flourishing development of technology and information. Circuit substrates have thus become more and more important in consumer electronic products and their accessories. In recent years, electronic products follow the trend of diversity and high performance, and miniaturization is a basic requirement of product design. Therefore, electronic products need to be shaped from a planar shape into a three-dimensional (3D) shape.
The production of curved circuit boards is one key point of manufacturing 3D electronic products. However, there is a lack of a common technology having the advantages of low cost and easy processing to shape the planar circuit into a non-planar 3D shape. That is, when compared to the planar circuit, the 3D circuit is subject to many limitations when processing, such that process difficulties and production cost cannot be reduced.
Although the planar circuit can be shaped into a non-planar three-dimensional shape by edge cutting or double sided tape, it is not practical in consideration of cost per processing time. There is an urgent need for a common technology to reduce process difficulties and production cost of the production of the 3D circuit.
The object of the instant disclosure is to provide a manufacturing method of a curved circuit board which not only assists in reducing processing difficulties and production cost, but also acts to manufacture a curved circuit board which can meet the requirements of various electronic products such as smartphone, tablet computer, and electronic paper.
In order to achieve the aforementioned objects, according to an embodiment of the instant disclosure, the manufacturing method comprises the following steps: providing a flexible substrate; forming a patterned catalyst layer on the flexible substrate; depositing metal on the patterned catalyst layer by electroless plating to form a wiring substrate, wherein the wiring substrate includes a planar wiring structure; and placing the wiring substrate into a mold having a molding surface with a three-dimensional design, and then executing a heating process to shape the planar wiring structure to a three-dimensional wiring structure, wherein the heated wiring substrate is laminated to the molding surface of the mold.
In order to achieve the aforementioned objects, according to another embodiment of the instant disclosure, the manufacturing method comprises the following steps: providing a flexible substrate; forming a patterned catalyst layer on the flexible substrate to obtain a planar composite structure; placing the planar composite structure into a mold having a molding surface with a three-dimensional design, and then executing a heating process to shape the planar composite structure to a three-dimensional composite structure, wherein the three-dimensional composite structure is laminated to the molding surface of the mold; and depositing metal on the patterned catalyst layer of the three-dimensional composite structure by electroless plating to form a three-dimensional wiring structure.
Another object of the instant disclosure is to provide an electronic product using a curved circuit board, characterized in that the curved circuit board comprises a three-dimensional flexible substrate, a patterned catalyst layer, and a three-dimensional wiring structure. The patterned catalyst layer is conformally formed on the three-dimensional flexible substrate. The three-dimensional wiring structure is formed only on the patterned catalyst layer. The surfaces of the three-dimensional flexible substrate, the patterned catalyst layer and the three-dimensional wiring structure have the same three-dimensional design.
The benefits of the present invention include: by executing the process of producing a three-dimensional composite structure and then forming a circuit pattern on the three-dimensional composite structure by electroless plating, or by executing the process of producing a planar circuit board with a circuit pattern by electroless plating and then shaping the planar circuit board into a three-dimensional shape, the manufacturing method not only can reduce processing difficulties, but also can accurately control the curvature of the resulting curved circuit board to meet the quality requirements.
In order to further appreciate the characteristics and technical contents of the instant disclosure, references are hereunder made to the detailed descriptions and appended drawings in connection with the instant disclosure. However, the appended drawings are merely shown for exemplary purposes, rather than being used to restrict the scope of the instant disclosure.
Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
Notably, the terms first, second, third, etc., may be used herein to describe various elements or signals, but these signals should not be affected by such elements or terms. Such terminology is used to distinguish one element from another or a signal with another signal. Further, the term “or” as used herein in the case may include any one or combinations of the associated listed items.
Please refer to
In the step S100, referring to
The patterned catalyst layer 12 is printed on the planar flexible substrate 11 according to a predetermined circuit pattern. Specifically, a screen printing plate (not shown) is disposed above the planar flexible substrate 11, wherein the screen printing plate has a hollow section in relation to the design of the circuit pattern. Next, a resin-based catalyst material is pushed through the screen printing plate by scraping onto the surface of the planar flexible substrate 11, and then curing thermally. Preferably, the thickness of the patterned catalyst layer 12 is between 0.1 μm to 30 μm.
For the instant embodiment, the patterned catalyst layer 12 includes a catalyst and a curing agent, wherein the content of the curing agent is about 1% to about 10% by weight. The catalyst can be used for electroless metal deposition and can be changed in relation to the desired metal. For example, the catalyst can be selected from the group consisting of palladium-based catalysts, silver-based catalysts, carbon-based catalysts, and combinations thereof. The used catalyst is suitably selected from palladium-based catalysts such as palladium sulfate, palladium chloride, diammine dichloropalladium (II), tetraammine dichloropalladium(II), and diaminedinitritopalladium (II). Specific examples of the curing agent include an aliphatic amine curing agent, cyclic aliphatic amine curing agent, polyamide curing agent, aromatic amine curing agent, acid anhydride type curing agent, lewis acid type curing agent, and imidazole type curing agent.
In the step S102, referring to
For the instant embodiment, the planar wiring structure 13 can be made from metals having better conductivity such as gold, silver, copper, nickel, aluminum, and chromium. There is no particular restriction as to the material for the planar wiring structure 13. Preferably, an electroless copper plating process is used for producing the wiring substrate 10, wherein the processing time is between 5 and 500 minutes. However, the processing time can be adjusted according to the desired thickness of the planar wiring structure 13. Moreover, the electroless plating bath used can be a basic plating bath having a pH-value within the range 9 to 14 such as a plating bath including copper chloride (CuCl2), and the temperature of which can range from about 20° C. to about 100° C.
In the step S104, referring to
For the instant embodiment, the mold 20 can be placed directly into the heater or fixed at a suitable position in the heater. The mold 20 can be made of metal, ceramic, or any high temperature resistant material, used to heat the wiring substrate 10 to a temperature within the range 150° C. to 600° C. There is no particular restriction regarding the heating means of the mold 20.
Referring to
Referring to
Please refer to
Please note that the feature of the second embodiment for manufacturing a curved circuit board is to produce a three-dimensional composite structure and then to form a circuit pattern on the three-dimensional composite structure by electroless plating. Comparing to the first embodiment, the feature of which is to produce a planar circuit board with a circuit pattern by electroless plating and then to shape the planar circuit board to a curved circuit board, the manufacturing method of the second embodiment is adapted for manufacturing a circuit substrate with a complex curved surface.
Referring to
Referring to
Preferably, for assisting the lamination of the three-dimensional composite structure on the molding surface 211 of the mold 20, a suction device (not shown) can be used to apply a negative pressure to the planar composite structure 10′ along a direction of moving close to/further away from the molding surface 211 through the vent hole 22. In various embodiments, due to an increase in thickness, a blowing device (not shown) and a suction device can be used to apply a negative pressure and a positive pressure concurrently to the planar composite structure 10′ along a direction of moving close to/further away from the molding surface 211 of the mold 20.
Referring to
The manufacturing method can further comprise a step of forming a protective layer 14 to cover the three-dimensional wiring structure 13′ (S206). The structural features of the protective layer 14 and methods of making the same are described in the first embodiment, and therefore these will not be discussed in more detail here.
Please note that the manufacturing methods of both the first and second embodiments can be used in manufacture of single-sided or double-sided curved circuit board 1. Specifically, the resulting single-sided curved circuit board 1, as shown in
The resulting double-sided curved circuit board 1 includes a three-dimensional flexible substrate 11′, two patterned catalyst layers 12, and two three-dimensional wiring structures 13′. The three-dimensional flexible substrate 11′ includes at least one conductive structure 15 embedded therein. The two patterned catalyst layers 12 are respectively formed on the two opposite surfaces of the three-dimensional flexible substrate 11′. The two three-dimensional wiring structures 13′ are respectively formed on the two patterned catalyst layers 12, and can be electrically connected to each other by the at least one conductive structure 15. The three-dimensional flexible substrate 11′, the two patterned catalyst layer 12 and the two three-dimensional wiring structures 13′ have the same three-dimensional configuration. In other words, the surfaces of the three-dimensional flexible substrate 11′, the two patterned catalyst layer 12 and the two three-dimensional wiring structures 13′ have the same three-dimensional design.
Referring to
To sum up, by executing the process of producing a three-dimensional composite structure and then forming a circuit pattern on the three-dimensional composite structure by electroless plating, or by executing the process of producing a planar circuit board with a circuit pattern by electroless plating and then shaping the planar circuit board into a three-dimensional shape, the manufacturing method not only can reduce processing difficulties, but also can accurately control the curvature of the resulting curved circuit board to meet the quality requirements.
Moreover, the manufacturing method can solve the lack of a common technology for shaping the planar circuit pattern into a three-dimensional shape and the problem of difficulty in operation. The resulting curved circuit board can meet the requirements of electronic, photoelectronic, and semiconductor industries.
In addition, the manufacturing method can be implemented in any known apparatus, and thus the production costs can be reduced. The manufacturing method can also be with the roll-to-roll (r2r) process for large-scale production.
The descriptions illustrated supra set forth simply the preferred embodiments of the instant disclosure; however, the characteristics of the instant disclosure are by no means restricted thereto. All changes, alterations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the instant disclosure delineated by the following claims.
