The present study evaluates the microstructural development and GHz electrical response of two solder systems: a multicomponent SnBiInZnAg (SBIZA) alloy and a ternary SnBiIn alloy. Microstructural analysis revealed that SBIZA joints formed an approximately 1.7 µm thin, continuous intermetallic compound (IMC) layer, whereas SnBiIn joints exhibited an approximately 3.5 µm thick, irregular IMC accompanied by significantly higher Sn/In oxide accumulation. These interfacial distinctions strongly influenced high-frequency performance. At 10 GHz, SBIZA exhibited lower insertion loss (–0.35 dB vs. −0.44 dB) and improved return loss (< −14 dB vs. −11.3 dB), together with a smaller insertion-loss deviation (< 0.20 dB) and a flatter group-delay response. Nonlinear radio frequency testing further showed that SBIZA reduced third-order intermodulation distortion by approximately 29 dB relative to SnBiIn. High-speed digital measurements demonstrated that SBIZA maintained a clean eye opening up to 56 Gbps, achieved a rise-time distortion of approximately 28 ps (compared with approximately 45 ps for SnBiIn), and supported bit error rate levels below 10−12. Overall, the results indicate that SBIZA provides superior microstructural stability and electrical reliability, positioning it as a promising candidate for next-generation low-temperature interconnects.
LiGWangSDingY, et al.Solder joint shape optimization and thermal-mechanical reliability improvement for microwave RF coaxial connectors. Microelectron Reliab2024; 154: 115345.
2.
WangDFanYChengYJ. W-Band High-Gain High-Efficiency Antenna Array in Glass Package Based on Low-Loss BGA-Formed AFSIW Feeding Network. IEEE Trans Components, Packag Manuf Technol2025. doi:10.1109/TCPMT.2025.3584756.
3.
YangJShinCLeeM, et al.Metal interconnection of high bandwidth memory in wafer level packaging. In: 2025 IEEE international interconnect technology conference (IITC). IEEE, 2025, pp.1–3.
4.
WangQCaiSYangS, et al.Comparison of high-speed shear properties of low-temperature Sn-Bi/Cu and Sn-In/Cu solder joints. J Mater Sci Mater Electron2024; 35: 76.
5.
WangCChangTy. Systematic study of liquid-state interfacial reactions between Co and In-Sn Solders with varying Sn contents. J Electron Mater2025; 54: 2589–2600.
6.
ZhuYLiZZhaoY, et al.Comparison of Sn/Cu solder joints enhanced with Bi, In, and Sb. Phys Scr2025; 100: 55904.
7.
NittaSTatsumiHNishikawaH. Creep behavior of low-temperature Sn-In solder using nanoindentation test. In: 2024 International 3D systems integration conference (3DIC). IEEE, 2024, pp.1–3.
8.
BelhadiMEAHamashaSAlahmerA, et al.The impact of Bi content on the coarsening kinetics of IMC particles and creep deformation under thermal cycling. J Electron Mater2024; 53: 380–393.
9.
ZhangSLiuJGanZ, et al.Microwave hybrid joining of SAC305-Ni@Sn composite solder: heating mechanism, mechanical reliability, and first-principles calculation. Mater Sci Eng A2025; 948: 149338.
10.
ZhangSZengCMaS, et al.Microwave hybrid joining using SAC305-xNi@Sn solder paste to achieve superior performance and high-efficiency heating and unveiling cross-scale mechanisms. Int J Therm Sci2025; 215: 109947.
11.
ZhangSQuanXLinC, et al.Investigation on electromigration failure behavior of SAC305/SnPb micro-hybrid solder joints for package-on-package techniques: experiment and simulation. Mater Lett2024; 377: 137394.
12.
MaoXSunQQiaoJ, et al.The study on low temperature reflow of antioxidant multicomponent solder paste on copper substrates. J Mater Res Technol2025.
13.
LiFPuCLiC, et al.Study on the effects of Ag addition on the mechanical properties and oxidation resistance of Sn–Zn lead-free solder alloy by high-throughput method. J Mater Sci Mater Electron2023; 34: 22.
14.
HeYZhengYLiuZ, et al.Zn additions modifying microstructure and properties of low-melting-point SnBiIn solder alloys. J Alloys Compd2025: 182234. doi:10.1016/j.jallcom.2025.182234
15.
ShuklaVAhmedOSuP, et al.Effect of Bi on the tensile and viscoplastic behavior of Sn-Ag-Cu-Bi alloys used for microelectronics applications. Metals (Basel)2024; 14: 03.
16.
Raushan KumarM. Comprehensive investigation of oxidation behavior on ternary In–Zn–Sn lead-free solder electronic materials. J Mater Sci Mater Electron2024; 35: 1467.
17.
SobralBSVieiraPSLimaTS, et al.Effects of Zn addition on dendritic/cellular growth, phase formation, and hardness of a Sn–3.5wt% Ag solder alloy. Adv Eng Mater2023; 25: 2201270.
18.
ZhaoTSongKZhuoY, et al.Effect of ground solder ball failure on signal interference between channels. In: 2024 IEEE international symposium on radio-frequency integration technology (RFIT). IEEE, 2024, pp.1–4.
19.
YangWChungDDL. Electric polarization and depolarization of solder, and their effects on electrical conduction. J Mater Sci Mater Electron2021; 32: 6214–6227.
20.
SongKGaoJFlowersGT, et al.The impact of the connection failure of ground solder balls on digital signal waveform. IEEE Trans Electromagn Compat2022; 65: 312–322.
21.
WaqarMChangYBKwonJ, et al.DDR4 Ball grid array package intermittent fracture effect on signal integrity. IEEE Trans Components, Packag Manuf Technol2023; 13: 70–78.
22.
YuXmYangZtLiuLj. Research on signal integrity of UWB BGA differential transmission structure based on HiTCE. In: 2022 International conference on microwave and millimeter wave technology (ICMMT). IEEE, 2022, pp.1–3.
23.
ZhuangQYaoKZhangC, et al.Permeable, three-dimensional integrated electronic skins with stretchable hybrid liquid metal solders. Nat Electron2024; 7: 598–609.
24.
MousaMMMohammedMMEl-KadyOA, et al.Microstructure, hardness, electrical, and thermal conductivity of SZCN solder reinforced with TiO2 and ZrO2 nanoparticles fabricated by powder metallurgy method. J Mater Sci Mater Electron2024; 35: 1133.
25.
Al-EzziASKaderEAlazzawiS. Effect of alloying elements on microstructural and electrical property in Sn–Cu–Bi lead-free solder alloys. Weld Int2024; 38: 211–224.
26.
ParkJKimD. Statistical eye diagrams for high-speed interconnects of packages: a review. IEEE Access2024; 12: 22880–22891.
27.
WeiZYuSWeiP. Research on low-insertion-loss packaging materials for DC-6GHz attenuation chips. Electronics (Basel)2024; 13: 1785.
28.
MorikawaTSekineSIkedaH, et al.Three-dimensional morphologies of CuSn intermetallic compounds in lead-free solder particles and their formation mechanisms. Mater Charact2025: 115436. doi:10.1016/j.matchar.2025.115436
29.
WangJChenWLiuD, et al.Effect of the ultrasonic-assisted soldering on the interfacial reaction and IMC growth behavior of SAC305 solder with Cu alloy substrates. J Mater Sci Mater Electron2023; 34: 1517.
30.
MingWUMinHWen-junSUN, et al.Oxidation behavior and intermetallic compound growth dynamics of SAC305/Cu solder joints under rapid thermal shock. Trans Nonferrous Met Soc China2023; 33: 3054–3066.
31.
WangFWangXLvZ, et al.A novel antioxidant and low-temperature Sn-Zn solder paste based on Zn@ Sn core-shell structure. Mater Today Commun2022; 31: 103356.
32.
RagabMAlsnaniHHammadAE, et al.The role of Sb on the microstructure and creep behaviors of Sn–6.5 Zn–0.3 Cu Pb-free solder alloy. J Mater Sci Mater Electron2024; 35: 1705.
33.
QiaoCSunXWangY, et al.A perspective on effect by Ag addition to corrosion evolution of Pb-free Sn solder. Mater Lett2021; 297: 129935.
34.
WuYFowlerHNWeddingtonN, et al.Effect of Sb and Ag additions on the melting and solidification of Sn-Bi solder alloys. MRS Adv2024; 9: 2–6.
35.
WangBLuJZhaoL, et al.Effect of Ag doping on mechanical properties of Cu6Sn5 intermetallic compounds. Metals (Basel)2024; 14.
36.
KangTYSeoDMinJ, et al.Quantification of performance variation and crack evolution of bond-wire interconnects under harsh temperature environments by S-parameter analysis. IEEE Trans Components, Packag Manuf Technol2021; 11: 990–998.
37.
ChiangYCChangYHYangZY, et al.Enhancing the high-frequency signal performance through surface morphological modification of Cu interconnects. Measurement (Mahwah N J)2025; 250: 117071.
38.
XiaoJKWangQFMaJG. Negative group delay circuits and applications: feedforward amplifiers, phased-array antennas, constant phase shifters, non-foster elements, interconnection equalization, and power dividers. IEEE Microw Mag2021; 22: 16–32.
39.
WanFLiNRaveloB, et al.S-parameter model of three parallel interconnect lines generating negative group-delay effect. IEEE Access2018; 6: 57152–9.
40.
KwonDAzarianMHPechtMG. Effect of solder joint degradation on rf impedance. In: 2008 12th IEEE workshop on signal propagation on interconnects. IEEE, 2008, pp.1–4.
41.
AzarianMHKwonDPechtM. Use of the skin effect for detection of interconnect degradation. IMAPS 42nd Internat Symp on Microelectronics2009.
42.
ChenZCaoYHeY. A Comprehensive Review of Surface Roughness Effects on Microwave Performance of Transmission Lines. IEEE Trans Microw Theory Tech2025.
43.
KrügerMNilsFNReichlH. Intermodulation distortion as indicator for interconnect degradation. In: 2010 Proceedings 60th electronic components and technology conference (ECTC). IEEE, 2010, pp.477–483.
44.
YangHLiuYHuangW, et al.Analysis of passive intermodulation distortion caused by asymmetric electrical contact. IEEE Trans Instrum Meas2022; 71: 1–5.
45.
YutthagowithPBabaY. An effective approximate mathematical expression for non-linear resistance characteristics of metal oxide elements. IEEE Trans Electromagn Compat2025.
