[目的]分析半加成工艺(SAP)中化学镍钯金产品基材渗镀上金的成因，为工业化生产中的关键工艺参数优化提供依据。[方法]研究了除钯温度和时间、活化时间、化学镀钯温度、化学镀金温度及化学钯/金倒槽对ABF基材渗镀缺陷率的影响。通过扫描电子显微镜(SEM)、能量色散谱(EDS)、聚焦离子束(FIB)等表征手段，深入分析了渗镀产品的微观形貌及元素分布。[结果]ABF基材内部约0.3～1.0μm深度存在不连续的Pd、Au渗镀，该现象与基材中残留的吸附Pd密切相关。通过优化除钯槽参数，以及定期对化学钯槽与化学镀金槽进行倒槽，可将基材渗镀缺陷率从100%降至0%。[结论]本研究明确了化学镍钯金工艺中基材渗镀的关键成因与控制途径，为提升产品品质与电子组装可靠性提供了理论依据与实践指导。

[Objective] This study aims to investigate the causes of substrate permeation plating(also referred to as “gold immersion”) in electroless nickel electroless palladium immersion gold(ENEPIG) surfaces during the semi-additive process(SAP), and to provide reference for optimizing key process parameters in industrial production. [Method] The effects of key parameters, including palladium removal temperature and time, activation time, electroless palladium plating temperature, electroless gold plating temperature, and the frequency of palladium and gold tank transfer-filtration, on the permeation plating defect rate of ABF substrate were studied. The microstructure and elemental distribution of the affected areas were characterized via scanning electron microscopy(SEM), energy-dispersive X-ray spectroscopy(EDS), and focused ion beam(FIB) techniques. [Result] Discontinuous permeation of Pd and Au was found in the ABF substrate at depths of 0.3-1.0 μm, a phenomenon closely related to the residual of adsorbed palladium. The substrate permeation plating defect rate was reduced from 100% to 0% by optimizing palladium removal parameters and implementing regular transfer-filtration of electroless palladium and gold plating baths. [Conclusion] This study clarifies the key causes and control strategies for substrate permeation plating in the ENEPIG process, providing both theoretical support and practical guidance for improving product quality and the reliability of electronic assembly.