电镀锡表面处理规范 / Electroplated Tin Surface Finish Specification
IPC-4554规定了电镀锡(Electroplated Tin)表面处理的工艺参数和质量要求，区别于化学浸锡，电镀锡可获得更厚的锡层(5-15μm)，适用于需要多次回流焊或长期存储的应用。标准涵盖镀液成分控制、电流密度范围、锡须抑制措施及镀层附着力测试方法。
标准条款
Tin Thickness Requirements / 锡层厚度要求
第10页
第1-25行
Immersion tin thickness shall be 0.8 to 1.5um. Thickness measurement by XRF per IPC-TM-650 2.3.28. Minimum 5 measurement points per board. Thickness uniformity across panel shall be within plus or minus 20 percent of target value.
Whisker Growth Control / 晶须生长控制
第18页
第1-28行
Tin whisker mitigation strategies shall be implemented. Matte tin process required with grain size control. Storage life shall not exceed 12 months at room temperature. Whisker length shall not exceed 50um after accelerated aging test per JEDEC JESD201.
Solderability Testing / 可焊性测试
第26页
第1-22行
Solderability test per IPC-TM-650 2.4.12 wetting balance method. Wetting time shall not exceed 2 seconds at 245C. Meniscus rise shall achieve 95 percent coverage. Test shall be performed after steam aging 8 hours to simulate shelf life.
