Authored By:
Herbert J. Neuhaus, Ph.D., and Charles E. Bauer, Ph.D.
TechLead Corporation
Portland, OR, USA
Summary
Solder plays a special role in the world of electronics manufacturing as evidenced by the disruptive nature of the lead-free movement. The intense search for attractive leadfree solders reveals the preeminent importance of solder to the industry. In fact, solder consumes so much attention that solder-less alternatives are often overlooked.
Material-based alternatives to solder include conductive adhesives and transient-phase compounds. Developments in nanotechnology spawned a virtual renaissance in conductive adhesives and other solder-less joining materials.
As a complement to the solder-less materials developments, embedded assemblies use conventional materials in novel ways to improve performance by cutting interconnect parasitics and increase reliability gains by eliminating wirebonds and solder-bumps. Freescale, Imbera, GE, Verdant, and many others develop and employ diverse approaches to embedding active devices.
Particle Interconnect represents another solder alternative. While originally developed for automated test, particle interconnect holds considerable promise in a variety of applications including LED assembly and printed electronics.
This presentation surveys the landscape of alternatives to solder in interconnect, packaging, and assembly. Next, the presentation treats practical implementation challenges such as yield management strategies and supply chain restructuring. Finally, the presentation concludes with a discussion of scenarios in which older alternatives offer highly compelling business and technical benefits.
Conclusions
The disruptive nature of the effort to replace lead-based solders reveals the central role played by solder in electronics assembly. Lead-free solders require higher temperatures and increase the thermal tolerance requirements of electronic components. As a result, the industry has become increasingly open to solder-less alternatives.
TechLead has identified three broad families of solder alternatives: materials-based, process-based, and structurebased. Each family enjoys renewed interest and new applications. As with many disruptive technologies, the need for some supply chain restructuring limits adoption. However, TechLead forecasts that demand for performance and reliability will overcome adoption barriers.
Initially Published in the SMTA Proceedings
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