Abstract In minimally invasive surgery, there is a continuous trend towards the miniaturization of instruments in order to keep the incisions as small as possible. In this context, extensive use is made of electrosurgery. In order to optimize and miniaturize electrosurgical instruments, new ultrathin insulation methods with film thicknesses below 50 μm need to be developed. These electrical insulation films must comply with the requirements of Standard DIN EN ISO 60601-2-2. For this purpose, a high-voltage insulation layer based on a diamond like carbon (DLC) multilayer in combination with a topping layer of Parylene C has been developed. With a total thickness of less than 50 μm, this film withstands an electrical high-voltage treatment of more than 1 kV required in Standard DIN EN ISO 60601-2-2. In addition to the film's dielectric strength, its adhesion and suitability for reprocessing were investigated. Link