镀通孔

镀通孔（PTH）是多层印刷电路板（PCB）中的基本互连结构，在高密度互连（HDI）基板中尤为关键。这些孔经过精确钻孔，穿透多个PCB层，然后进行全面的电镀工艺，在孔壁上沉积铜，以在不同导电层之间建立可靠的电气连续性。电镀工艺通常包括化学镀铜，随后进行电解镀铜，以达到所需的厚度和导电性。PTH使得复杂电子组件中的电信号能够进行三维布线，支持现代电子设备的小型化和功能增强。

PTH通过在绝缘的PCB基板材料中形成导电通路来发挥作用。在机械或激光钻孔穿过PCB叠层后，孔壁进行表面处理和活化。化学镀铜形成一层薄的导电种子层，随后电解镀铜增厚至所需铜厚。这形成了连续的导电孔壁，连接不同层上的铜走线，使电信号和电源能够垂直穿过PCB结构，同时保持机械完整性。

PTHs function by creating conductive pathways through insulating PCB substrate materials. After mechanical or laser drilling creates holes through the PCB stack-up, the hole walls undergo surface preparation and activation. Electroless copper deposition establishes a thin conductive seed layer, followed by electrolytic copper plating that builds up the required copper thickness. This creates continuous conductive barrels that connect copper traces on different layers, allowing electrical signals and power to pass vertically through the PCB structure while maintaining mechanical integrity.