Solderability Tests Toward Miniaturized Microelectronics: Applicability and Limitations of Micro-Wetting Balance Testing of SnAgCu and SnBi Solders
Source abstract
Abstract
This study presents a comprehensive investigation of the micro-wetting behavior of SAC305 and SnBi58 solders on chip components. Micro-wetting balance tests, which employ small solder globules, enable direct evaluation of solder wettability on miniature electronic components such as 1206 chip resistors and 1206 and 0603 chip capacitors. Unlike conventional wetting tests that use large solder baths, the micro-wetting method suppresses excessive solder rise, making it suitable for testing small-scale components. The results demonstrate that micro-wetting testing is a reliable method for evaluating solder wettability on chip components when appropriate globule size, test temperature, and experimental parameters such as immersion depth and speed are carefully controlled. Among the tested conditions, 2 mm diameter solder globules are identified as the optimal choice because they offer improved thermal management and reduced surface oxidation. The wetting times measured for SnBi58 are comparable to those obtained for conventional SAC305 solder, whereas the maximum wetting forces are generally lower. However, micro-wetting curves exhibit noticeable fluctuations, which complicate the analysis of additional parameters, such as maximum wetting force and wetting rate, and limit direct comparison with standard reference values.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Electronic Packaging and Soldering Technologies · Nanomaterials and Printing Technologies · 3D IC and TSV technologies
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Chair of Microintegration and Reliability, Faculty of Natural Sciences and Technology, Saarland University, 66123 Saarbrucken, Germany
References (41)
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1. Schüppstuhl, T., Franke, J., and Tracht, K. (2017). Challenges of the Miniaturization in the Electronics Production on the example of 01005 Components. Tagungsband des 2. Kongresses Montage Handhabung Industrieroboter, Springer.10.1007/978-3-662-54441-9 ↗
2. Recent Advances in Sn-Based Lead-Free Solder Interconnects for Microelectronics Packaging: Materials and Technologies10.1016/j.jmrt.2023.06.193 ↗
3. Miniaturization of Micro-Solder Bumps and Effect of IMC on Stress Distribution10.1007/s11664-016-4541-2 ↗
4. Lee, N.-C. (2008, January 9–12). Future Lead-Free Solder Alloys and Fluxes—Meeting Challenges of Miniaturization. Proceedings of the 2008 10th Electronics Packaging Technology Conference, Singapore.10.1109/EPTC.2008.4763539 ↗
5. Misaligned Flip-Chip Solder Joints: Prediction and Experimental Determination of Force-Displacement Curves10.1115/1.1463732 ↗
6. An Analysis of Solder Joint Formation and Self-Alignment of Chip Capacitors10.1109/TCPMT.2020.3034211 ↗
7. New Challenges of Miniaturization of Electronic Devices: Electromigration and Thermomigration in Lead-Free Solder Joints10.1016/j.matdes.2020.108726 ↗
8. Electromigration and Thermomigration in Pb-Free Flip-Chip Solder Joints10.1146/annurev.matsci.38.060407.130253 ↗
9. Investigation of Intermetallic Compound and Voids Growth in Fine-Pitch Sn–3.5Ag/Ni/Cu Microbumps10.1007/s10854-017-8096-7 ↗
10. Mechanical Properties of Intermetallic Compounds at Solder Joint Interfaces Investigated Using Nanoindentation Technique10.1016/j.jajp.2025.100356 ↗
11. Vijay, K. (2012, January 17–20). Miniaturization—Solder Paste Attributes for Maximizing the Print & Reflow Manufacturing Process Window. Proceedings of the 2012 4th Electronic System-Integration Technology Conference, Amsterdam, The Netherlands.10.1109/ESTC.2012.6542145 ↗
12. Illés, B., Géczy, A., Tafferner, Z., Skwarek, A., and Krammer, O. (2025, January 14–18). Low-Temperature Soldering (LTS) in the Electronics Industry: A Brief Review. Proceedings of the 2025 International Spring Seminar on Electronics Technology (ISSE), Budapest, Hungary.10.1109/ISSE65583.2025.11120985 ↗
13. Lee, B.-H., Chang, C.-Y., Li, C.-H., Lin, K.-S., Yueh, S.-L., and Kobayashi, S. (2018, January 14–18). New-Generation, Low-Temperature Lead-Free Solder for SMT Assembly. Proceedings of the SMTA Proceedings, Rosemont, IL, USA.
14. Huang, B., Dasgupta, A., and Lee, N.-C. (2004, January 14–16). Effect of SAC Composition on Soldering Performance. Proceedings of the IEEE/CPMT/SEMI 29th International Electronics Manufacturing Technology Symposium, San Jose, CA, USA.
15. Review of the Wettability of Solder with a Wetting Balance Test for Recent Advanced Microelectronic Packaging10.1080/10408436.2018.1490249 ↗
16. Wettability in Lead-Free Soldering: Effect of Plasma Treatment in Dependence on Flux Type10.1016/j.apsusc.2024.160447 ↗
17. Current Status on Optimizing Solder Wettability from Substrate Surface Treatment, Alloying Solder, Flux, and Process Environments10.1016/j.mssp.2025.109978 ↗
18. Dušek, K., Novák, M., and Mach, P. (2010, January 12–16). Solderability Measurement of Copper with Different Surface Finishes. Proceedings of the 33rd International Spring Seminar on Electronics Technology, ISSE 2010, Warsaw, Poland.10.1109/ISSE.2010.5547267 ↗
19. Solderability Testing of Sn-Ag-XCu Pb-Free Solders on Copper and Au-Ni-Plated Kovar Substrates10.1007/s11664-005-0217-z ↗
20. Bušek, D., Plaček, M., and Růžička, D. (2017, January 10–14). Wetting Balance Test—Comparison of Solder Alloys Wetting. Proceedings of the 2017 40th International Spring Seminar on Electronics Technology (ISSE), Sofia, Bulgaria.10.1109/ISSE.2017.8000923 ↗
21. Wetting and Reaction of Sn-2.8Ag-0.5Cu-1.0Bi Solder with Cu and Ni Substrates10.1007/s11664-005-0239-6 ↗
22. Lead-Free Solders in Microelectronics10.1016/S0927-796X(00)00010-3 ↗
23. The Solderability Testing of Surface Mount Devices Using the GEC Meniscograph Solderability Tester10.1108/eb043849 ↗
24. Simulation and Interpretation of Wetting Balance Tests Using the Surface Evolver10.1115/1.2792143 ↗
25. Quantitative Solderability Measurement of Electronic Components—Part I10.1108/eb037701 ↗
26. Klabacka, E., and Urbanek, J. (2006, January 6–7). A Note on Some Limitations in the Wetting-Balance Measurements and How to Deal with Them. Proceedings of the 2006 International Conference on Applied Electronics, Pilsen, Czech Republic.10.1109/AE.2006.4382972 ↗
27. Sargent, P.M., Tang, A.C.T., and Gordon, F.H. (1991, January 16–18). An Experimental Study of the Variation of Wettability of SMDs Using the Micro-Globule Wetting Method. Proceedings of the [1991 Proceedings] Eleventh IEEE/CHMT International Electronics Manufacturing Technology Symposium, San Francisco, CA, USA.
28. Conway, P.P. (1995, January 2–4). Solderability Testing of Alternate Component Termination Materials with Lead Free Solder Alloys. Proceedings of the Seventeenth IEEE/CPMT International Electronics Manufacturing Technology Symposium. “Manufacturing Technologies—Present and Future”, Austin, TX, USA.
29. Correlation between Microstructure Evolution and Mechanical Strength in the Sn–3.0Ag–0.5Cu/ENEPIG Solder Joint10.1016/j.msea.2013.05.058 ↗
30. Phoosekieaw, P., and Khunkhao, S. (2012, January 16–18). A Study of Several Board Finish Solderability with Sn-Ag-Cu under Different Atmospheres. Proceedings of the 2012 9th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, Phetchaburi, Thailand.10.1109/ECTICon.2012.6254127 ↗
31. The Effect of Ni and Bi Additions on the Solderability of Sn-0.7Cu Solder Coatings10.1007/s11664-019-07596-7 ↗
32. Relationship between Free Solder Thickness to the Solderability of Sn–0.7Cu–0.05Ni Solder Coating during Soldering10.1007/s10854-018-00647-5 ↗
33. Moyer, J., and Zhang, W. (, January 7–12). Solder Wetting Measurement of Back Contact Paste Using a Wetting Balance. Proceedings of the 2009 34th IEEE Photovoltaic Specialists Conference (PVSC), Philadelphia, PA, USA.10.1109/PVSC.2009.5411516 ↗
34. (2021). Environmental Testing—Part 2-20: Tests—Tests Ta and Tb: Test Methods for Solderability and Resistance to Soldering Heat of Devices with Leads (Standard No. IEC 60068-2-20:2021).
35. (2011). Solderability Tests for Component Leads, Terminations, Lugs, Terminals and Wires (Standard No. IPC/EIA S-STD 002D).
36. (2003). Solderability Tests for Printed Boards (Standard No. IPC J-STD-003B).
37. Bejan, A. (2013). Convection Heat Transfer, Wiley. [1st ed.].10.1002/9781118671627 ↗
38. Lumped Capacitance Thermal Modelling Approaches for Different Cylindrical Batteries
39. Thermal Conductivity of Molten Lead-Free Solders10.1007/s10765-006-0035-4 ↗
40. Evaluation of Solder/Substrate Thermal Conductance and Wetting Angle of Sn–0.7 wt%Cu–(0–0.1 wt%Ni) Solder Alloys10.1016/j.matlet.2014.11.088 ↗
41. Solderability Testing of 95.5Sn-3.9Ag-0.6Cu Solder on Oxygen-Free High-Conductivity Copper and Au-Ni-Plated Kovar10.1007/s11664-003-0218-8 ↗