The purpose of the experiment was to indicate which element of the production process of flexible printed circuit boards is optimal in terms of the reliability of final products. According to the Taguchi method, in the experiment, five factors with two levels each were chosen for the subsequent analysis. These included the number of conductive layers, the thickness of the laminate layer, the type of the laminate, the diameter of the plated holes, and the current density in the galvanic bath. The reliability of the PCBs in the produced variations was verified using the Interconnect Stress Test environmental test. The qualitatively best variant of the board construction was indicated using the signal-to-noise ratio and the analysis of variance method for each factor. The factors determined to be the most important in terms of reliability were the number of conductive layers and the current density in the galvanic bath. The optimal variant of the board construction was two conductive layers on a polyimide laminate, where the laminate layer was 100 μm thick, the hole diameter was equal to 0.4 mm, and current density was 2 A/dm² in the galvanic bath. Therefore, the plated experiment indicated the factors needed to obtain a high-quality product with a low failure rate.

The purpose of the experiment was to indicate which element of the production process of flexible Printed Circuit Board is optimum in terms of the reliability of final products. According to the Taguchi method in the experiment five factors, two levels each, were chosen for the subsequent analysis. These include: the number of conductive layers, the thickness of the laminate layer, type of the laminate, the diameter of the plated holes, the current density in the galvanic bath. The reliability of the PCBs in produced variations was verified using the Interconnect Stress Test environmental test. The qualitatively best variant of the board construction was indicated using the signal-to-noise ratio and analysis of variance method for each factor. The factors that turned out to be the most important in terms of reliability are the number of conductive layers and the current density in the galvanic bath. The optimal variant of the board construction is two conductive layers, on a polyimide laminate, where laminate layer is 100 μm thick, hole diameter equal to 0.4 mm and current density of 2 A/dm2 in the galvanic bath. Therefore the plated experiment indicated factors needed to obtain a high-quality product with a low failure rate.

The increasing power density of modern electronic systems intensifies challenges related to heat dissipation and long-term reliability. Insulated metal substrates (IMS), particularly three-dimensional (3D), are increasingly used as integrated thermal–mechanical solutions in high-power electronics. However, their complex geometry and material interfaces introduce new reliability concerns, especially at solder joints. This study investigates the evolution of intermetallic compounds (IMCs) in solder joints formed on 3D aluminum IMSs with ENIG metallization, focusing on SAC305 and Sn42Bi57Ag1 solder alloys. Solder joints were subjected to environmental aging under high-temperature, high-humidity, and thermal-shock conditions to simulate realistic service environments. Microstructural and compositional analyses of the interfacial IMC layers were performed, together with measurements of IMC thickness evolution. The results show that aging significantly modifies the chemical composition and morphology of IMC layers in both solder systems. In SAC305 joints, progressive development of (Cu,Ni)₆Sn₅ phases with increasing Cu participation was observed. In Sn42Bi57Ag1 joints, Bi affected reaction kinetics but did not alter the diffusion-controlled nature of IMC growth. Thickness measurements indicate higher sensitivity of SAC305 joints to environment-assisted interfacial degradation, while Sn42Bi57Ag1 joints exhibit greater susceptibility to stress-assisted IMC growth during severe thermal cycling. These findings highlight the distinct reliability behaviors of tested solders on 3D IMSs and provide insight into their suitability for high-power electronic applications.