In the manufacture of pacemakers and defibrillators, plasma is used in the header assembly, in creating the electronics package, cleaning the can post laser welding, and treatment of the external electronic leads. Plasma cleans mold release and activates the surface of pacemaker and defibrillator headers to improve the bond between the header and can. It can also be used to remove titanium oxide from laser welding processes. It is a superior final cleaning step that helps improve the biocompatibility and bondability of many medical product or components.
For example, the pacemaker header is typically manufactured from a polyurethane such as tecothane. This molded material often has a mold release compound that can inhibit the adhesive bond between the header and the titanium can. Plasma is used to remove the mold release compound and enhance this adhesive bond. The figure below displays the adhesion strength of the tecothane to the titanium can as a function of concentration of the mold release wax compound. The results show that as the concentration of the wax compound on the tecothane surface decreases the adhesion increases.
Other applications for plasma in pacemaker/defibrillator manufacturing include: cleaning hybrid electronic circuitry prior to wire bonding, underfill; molding/encapsulation, and conformal coating to improve yield, reliability and performance of the electronic device; cleaning titanium can both pre and post laser weld; and improving adhesion of electrical insulator coatings.