JP-7856116-B2 - Manufacturing method of copper-clad laminates

Inventors

• 下地 匠
• 西山 芳英

Assignees

• 住友金属鉱山株式会社

Dates

Publication Date

20260511

Application Date

20240119

Claims (4)

1. An electrolytic plating process to obtain an intermediate copper-clad laminate by conveying a substrate by roll-to-roll and forming a copper plating film on the surface of the substrate by electrolytic plating, The process includes a cutting step of cutting the intermediate copper-clad laminate with a slitter to obtain the final copper-clad laminate, In the electroplating process described above, a shielding plate is placed between the central region of the substrate in the TD direction and the anode to reduce the current density in a predetermined region of the substrate, thereby forming a conductive layer having a strip-shaped thick film region and a thin film region along the MD direction. In the cutting process, the copper-clad laminate intermediate is cut in the thick film region to form the copper-clad laminate final product, in which the power supply region, which is the region near the edge along the MD direction, has a conductor layer that is thicker than the wiring formation region, which is all or part of the other region. A method for manufacturing copper-clad laminates, characterized by the following:
2. In the electroplating process described above, a plurality of shielding plates are arranged in the TD direction between the substrate and the anode to form the conductive layer having a plurality of thick film regions. A method for manufacturing a copper-clad laminate according to claim 1.
3. The shielding plate has multiple holes that penetrate through both its front and back surfaces. A method for manufacturing a copper-clad laminate according to claim 1.
4. The conductor layer has an average thickness of 0.5 μm or more in the power supply region and an average thickness of less than 0.5 μm in the wiring formation region. A method for manufacturing a copper-clad laminate according to claim 1.

Description

This invention relates to a method for manufacturing copper-clad laminates. More specifically, this invention relates to a method for manufacturing copper-clad laminates used in the manufacture of flexible printed circuit boards (FPCs) and the like. Flexible printed circuit boards, in which wiring patterns are formed on the surface of a resin film, are used in electronic devices such as LCD panels, laptop computers, digital cameras, and mobile phones. Flexible printed circuit boards (PCBs) are obtained by forming wiring patterns on copper-clad laminates using methods such as the semi-additive and subtractive methods. The semi-additive method is particularly used when forming fine wiring or when high-precision wiring dimensions are required. The manufacturing of flexible printed circuit boards using the semi-additive method is carried out in the following steps: First, a resist layer is formed on the surface of the conductive layer of the copper-clad laminate. Next, openings are formed in the resist layer in the areas where the wiring pattern will be formed. Then, electroplating is performed using the conductive layer exposed through the openings in the resist layer as the cathode to form the wiring. Finally, the resist layer is removed, and the conductive layer other than the wiring is removed by flash etching or other methods. This results in a flexible printed circuit board. In the semi-additive method, unnecessary portions of the conductor layer of the copper-clad laminate are removed by etching. If the conductor layer is too thick, the etching time increases, and etching progresses through the wiring, making it difficult to maintain a rectangular cross-sectional shape for the wiring. Therefore, from the perspective of maintaining a rectangular cross-sectional shape for the wiring, a thinner conductor layer in the copper-clad laminate is preferable. However, if the conductor layer is thin, problems can arise when forming the wiring section by electroplating. Specifically, to form the wiring section by electroplating, electrode terminals are connected to the edge of the conductor layer, and power is supplied to the conductor layer. Here, if the conductor layer is thin, the electrical resistance is high, making it difficult to supply sufficient current. Furthermore, the portion of the conductor layer in contact with the electrode terminals becomes high-voltage, which can cause dissolution or abnormal deposition of the conductor layer, hindering current supply. Therefore, to prevent the dissolution of the conductive layer, etc., the current density in electroplating is set low. For example, Patent Document 1 describes setting the current density to 1 A/ dm² when forming wiring on a substrate having a nickel-chromium alloy film with a thickness of 10 nm and a copper layer with a thickness of 100 nm using a semi-additive method. However, if the current density is too low, stable electroplating becomes difficult. Japanese Patent Publication No. 2010-108964 This is a partially enlarged cross-sectional view of a copper-clad laminate according to one embodiment.Figure (A) is a plan view of a copper-clad laminate according to one embodiment. Figure (B) is a cross-sectional view of the same copper-clad laminate.This is an explanatory diagram showing the manufacturing procedure for flexible printed circuit boards using the semi-additive method.Figure (B) shows a cross-section of the copper-clad laminate according to the second embodiment. Figure (B) shows a cross-section of the copper-clad laminate according to the third embodiment. Figure (B) shows a cross-section of the copper-clad laminate according to the fourth embodiment.This is an explanatory diagram showing the manufacturing procedure for copper-clad laminates.This is an explanatory diagram showing the manufacturing procedure of another embodiment. Next, embodiments of the present invention will be described based on the drawings. [Copper-clad laminated board] As shown in Figure 1, the copper-clad laminate 1 according to one embodiment of the present invention consists of a base film 10 and a conductive layer 20 formed on the surface of the base film 10. A resin film such as a polyimide film or a liquid crystal polymer (LCP) film can be used as the base film 10. While not particularly limited, the thickness of the base film 10 is generally 10 to 100 μm. The conductive layer 20 consists of a metal layer 21 formed by a dry deposition method such as sputtering, and a copper plating film 22 formed by electrolytic plating. The metal layer 21 and the copper plating film 22 are laminated in this order on the surface of the base film 10. The metal layer 21 consists of a base metal layer 21a and a copper thin film layer 21b. The base metal layer 21a and the copper thin film layer 21b are laminated in this order on the surface of the base film 10. Generally, the base metal layer 21a consists of nickel, chromium, or a nickel-chromium alloy. The base metal layer 21a is