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Proceedings Paper

Laser micro welding of copper and aluminum
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Paper Abstract

Aluminum combines comparably good thermal and electrical properties with a low price and a low material weight. These properties make aluminum a promising alternative to copper for a large number of electronic applications, especially when manufacturing high volume components. However, a main obstacle for a wide use of this material is the lack of a reliable joining process for the interconnection of copper and aluminum. The reasons for this are a large misalignment in the physical properties and even more a poor metallurgical affinity of both materials that cause high crack sensitivity and the formation of brittle intermetallic phases during fusion welding. This paper presents investigations on laser micro welding of copper and aluminum with the objective to eliminate brittle intermetallic phases in the welding structure. For these purposes a combination of spot welding, a proper beam offset and special filler material are applied. The effect of silver, nickel and tin filler materials in the form of thin foils and coatings in a thickness range 3-100 μm has been investigated. Use of silver and tin filler materials yields to a considerable improvement of the static and dynamic mechanical stability of welded joints. The analysis of the weld microstructure shows that an application even of small amounts of suitable filler materials helps to avoid critical, very brittle intermetallic phases on the interface between copper and solidified melt in the welded joints.

Paper Details

Date Published: 23 February 2006
PDF: 6 pages
Proc. SPIE 6107, Laser-based Micropackaging, 610703 (23 February 2006); doi: 10.1117/12.648376
Show Author Affiliations
Ihor Mys, Bayerisches Laserzentrum GmbH (Germany)
Michael Schmidt, Bayerisches Laserzentrum GmbH (Germany)


Published in SPIE Proceedings Vol. 6107:
Laser-based Micropackaging
Friedrich G. Bachmann; Willem Hoving; Yongfeng Lu; Kunihiko Washio, Editor(s)

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