An automotive supplier requested "thick gold" for durability, thinking more is better. The fabricator applied 0.25 µm of gold. During thermal cycling and vibration testing, the solder joints cracked due to gold embrittlement (formation of AuSn4 intermetallics). IPC-4556 caps gold at 0.125 µm to avoid this.
Many large engineering universities and defense contractors have site licenses to IPC standards. Check your internal technical library before purchasing. ipc-4556 pdf
💡 When measuring these layers, IPC-4556 requires readings to be taken on a nominal pad size of to ensure accuracy across the board. If you'd like to refine this draft, tell me: IPC-4556 caps gold at 0
The IPC-4556 PDF refers to a specific document published by the Institute for Printed Circuits (IPC), now known as IPC, a trade association that develops standards for the electronics industry. The document, titled "IPC-4556, Specification for Performance Requirements for Stencil Fabrication Methods Used for Ball Grid Array (BGA), Chip Scale Array (CSA), and Other High Density Component Assembly," outlines the performance requirements for stencil fabrication methods used in the assembly of high-density electronic components. 💡 When measuring these layers, IPC-4556 requires readings