Laser Micro-Joining of Dissimilar and Biocompatible Materials

Ulrich-Andreas Russek*, Ingo Bauer*, Hans J. Herfurth **, Reiner Witte **

*Fraunhofer Institute for Laser Technology, Steinbachstraße 15, 52074 Aachen

** Fraunhofer Center for Laser Technology, 46025 Port Street, Plymouth, MI 48170

Abstract:

Micro-joining and hermetic sealing of biocompatible materials is a critical issue for a broad spectrum of biomedical products and devices. Today, biocompatible titanium is widely applied as a material for orthopedic implants as well as for the encapsulation of implantable devices such as pacemakers, defibrillators, and neural stimulator devices. Laser welding is the process of choice to hermetically seal such devices. However, new biomedical products, in particular implantable microsystems, pose new challenges to the assembly and packaging process based on the higher level of integration, the small size of the device’s features, and the type of materials and material combinations. In addition to metals, devices will also include glass, ceramic and polymers as biocompatible building materials that must be reliably joined in similar and dissimilar combinations. Since adhesives and soldering lack long-term stability or do not meet biocompatibility requirements, new joining techniques are needed to address these joining challenges. Localized laser bonding and welding provides some promising developments in this area. This paper will describe the latest achievements in micro-joining of metallic and non-metallic materials. The focus is on the material combinations of metal-polymer, polymer-glass, metal-glass and metal-ceramic using CO2, Nd:YAG and diode lasers. The potential for applications in the biomedical sector will be demonstrated.