Lead-free solder foil and method for manufacturing the same

The lead-free solder foil with integrated composite filaments addresses the limitations of existing solder materials by ensuring high-temperature resistance, minimal voids, and improved thermal conductivity, enhancing the reliability and lifespan of solder connections.

JP7883438B2Active Publication Date: 2026-07-01PFARR STANZTECHN
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Patent Information

Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
PFARR STANZTECHN
Filing Date
2021-02-08
Publication Date
2026-07-01

AI Technical Summary

Technical Problem

Existing lead-free solder materials fail to provide high-temperature resistant solder connections with minimal voids and cavities, are prone to deformation during soldering, and have limited thermal conductivity, leading to reduced lifespan and reliability in power electronics applications.

Method used

A lead-free solder foil with composite filaments integrated into a soft solder matrix, allowing for precise geometric control and high thermal reliability through intermetallic compound formation without additional pressure or heat treatment, ensuring minimal voids and improved conductivity.

Benefits of technology

The solder foil achieves high-temperature resistant connections with enhanced thermal conductivity and extended lifespan by minimizing voids and cavities, while maintaining structural integrity under thermal stress.

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Abstract

lead-free solder foil The present invention relates to a lead-free solder foil for connecting metallic and / or metal-coated components. The object of the present invention is to develop a lead-free solder foil that allows for the adjustment of a defined joint area geometry and achieves a high temperature resistant solder connection, which ensures high reliability even in stepwise processes and increases the thermal conductivity of the connection area, while minimizing the formation of holes and / or voids. The lead-free solder foil (1) according to the present invention is configured such that two or more composite filaments (3) are individually clad in a soft solder matrix (2) between two soft solder tapes, parallel to each other and to the tape sides, provided that the composite filaments (3) have a core (4) made of a stronger metal / metal alloy with a higher melting point than the soft solder matrix (2), and a jacket (5) is arranged around the core (4), made of another metal / metal alloy, and that after the roll-cladding process, there is still 5 μm to 15 μm of soft solder material above and below at least one of the cores (4).
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