Copper core balls, also known as copper core solder balls or copper-core balls, are composite solder balls with a copper core and an outer layer plated with nickel and tin, forming a multi-layer structure. Their core characteristic is that the copper core does not melt at high temperatures, maintaining stable geometric dimensions. This gives them a significant advantage in advanced semiconductor assembly fields such as high-density 3D packaging, narrow-pitch packaging, and high-performance area array packaging.
Packaging Types: Copper core balls are mainly used in 3D packaging (such as stacked chip-on-package), wafer-level chip-scale packaging (WLCSP), and area array packaging requiring high reliability. Their core value lies in ensuring stable gaps between packages after multiple reflow soldering cycles, preventing solder joint collapse or bridging short circuits.
Size Specifications: The diameter of the copper core ball is a key parameter. The industry typically categorizes them by size: less than 200 micrometers, 200-500 micrometers, and greater than 500 micrometers.
Precise selection is required based on the chip electrode pad size, package pitch, and gap requirements. For example, copper core solder balls with a diameter of 0.3 mm have been extensively studied and applied.
