SMT Processing using Printed Anisotropic Conductive Epoxy
There are many options on the market for unpackaged, bare die with advanced capabilities, however these chips are often designed for wire bonding interconnection. This paper discusses three designs successfully transitioned from previously wire-bonded die to bare die direct-to-circuit attachment using standard SMT pick-and-place equipment.
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Authored By:
John Yundt
SunRay Scientific, Inc.
NY, USA
Summary
There are many options on the market for unpackaged, bare die with advanced capabilities, however these chips are often designed for wire bonding interconnection. This prevents them from being readily used in Flexible Hybrid Electronics (FHE) applications. Rigid boards are the substrate option for wire-bonded bare die attach, or wire-bonding of the die within a package for SMT assembly. This paper discusses three designs successfully transitioned from previously wire-bonded die to bare die direct-to-circuit attachment using standard SMT pick-and-place equipment. Work for one case was performed under a funded grant and the others were commercial customer requests. The bare die were attached using one interconnect material, a stencil-printed Anisotropic Conductive Epoxy (ACE) for flexible hybrid electronics (FHE).
Conclusions
The Anisotropic Conductive Epoxy and ease of use advances current FHE packaging. Lower profile component attachment on flexible substrates enables smart labels not limited by rigidity and thickness. This emerging ACE is compatible with SMT lines’ sheet-to-sheet (S2S) processing. The case studies presented share the results of transitioning an existing wire-bonded product design to an FHE system using Anisotropic Conductive Epoxy on existing SMT infrastructure, with potential 50% reduction in thickness, reduced area, and higher throughput. With additional process development, this approach of enabling manufacture of enhanced capability IoT systems using existing die and SMT infrastructure could be made widely available to US contract manufacturers.
Initially Published in the SMTA Proceedings
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