Laser microjoining of dissimilar and biocompatible materials

Abstract

Micro-joining and hermetic sealing of dissimilar and biocompatible materials is a critical issue for a broad spectrum of products such as micro-electronics, micro-optical and 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 joining is the process of choice to hermetically seal such devices. Laser joining is a contact-free process, therefore minimizing mechanical load on the parts to be joined and the controlled heat input decreases the potential for thermal damage to the highly sensitive components. Laser joining also offers flexibility, shorter processing time and higher quality. However, novel biomedical products, in particular implantable microsystems currently under development, 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 often lack long-term stability or do not meet biocompatibility requirements, new joining techniques are needed to address these joining challenges. Localized laser joining provides promising developments in this area. This paper describes the latest achievements in micro-joining of metallic and non-metallic materials with laser radiation. The focus is on material combinations of metal-polymer, polymer-glass, metal-glass and metal-ceramic using CO2, Nd:YAG and diode laser radiation. The potential for applications in the biomedical sector will be demonstrated

Laser transmission joint between PET and titanium for biomedical application

“…The group of metal materials includes titanium, platinum, gold and stainless. Non-metals play an even more important role based on their biocompatibility include glass, sapphire, silicon and polymers, as be pointed out by Bauer et al (2004).…”

Finite element modeling of transmission laser microjoining process

“…Transmission laser joining at micro scale has not been studied well yet. We studied the laser microjoining of dissimilar and biocompatible materials using both diode and fiber lasers and observed that the joining of glass to silicon and polymer to metal is very promising [13]. As part of the study, we developed an experimental setup (Figs.…”

“…With the advent of biomedical implants and their encapsulation, the laser bonding technique has potential to become a unique joining process for its high precision and biocompatibility property, as no additional adhesive materials are required in this case. Our research group in collaboration with Fraunhofer USA has been studying the applicability of laser fabrication process in joining dissimilar and biocompatible materials [6][7][8][9][10][11][12][13][14].…”

Laser Fabrication and Characterization of Adhesive-Free Joints For Encapsulation of Biomedical Implant Devices

“…A transmission joining configuration [7] was used in which a clamping pressure of 200 MPa was used for the fabrication of the samples examined in this work. The laser beam with a total power of 1.0 W was loosely focused on the Ti surface to a spot with diameter of 300gam.…”

“…The feasibility of laser joining PI to titanium and PI to titanium-coated glass has been investigated, and ranges of processing parameters that permit successful joining have been identified [7]. In order to understand the influence of the laser fabrication conditions on the joint quality and stability, we examined laser-fabricated joints between PI and titanium-coated borosilicate glass (BSG) in tensile mechanical failure tests and by optical microscopy, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy.…”