Jeffrey Barlow¹, Ryan Lake¹, Christoph Schiffers^2
1CemeCon Inc., Horseheads, NY
²CemeCon AG; Würselen, Germany
It’s a clear trend: cutting tools are becoming smaller and more precise. It started with watchmaking and today’s drivers for this development are medical and dental as well as the 3C industry. AI technology makes PCB tools for drilling computer boards a high-volume application for extremely small tools. The explosion of computing power turned simple two-sided computer boards into highly sophisticated stacks of 10 or more layers which must be precisely interconnected. The super dense packaging in electronics makes a drill of Ø0,25 mm the new standard and requires board materials with ceramic fillers or glass interlayers.
HiPIMS is the best suited coating technology for micro tools since it gives smooth coatings without any droplets, a dense and fine-grained morphology of the film together with low intrinsic stresses.
More knobs to turn – HiPIMS gives effective control over the plasma. The multiple settings of HiPIMS allow the energy pulses to be tailoring for micro tools. This avoids antenna effects and defects because of over-etching the fine geometry. Precision machining with micro tools requires super sharp cutting edges. The unique HiPIMS feature of synchronizing the pulses at the cathodes with the HiPIMS Bias supply is the key to actively managing the intrinsic stresses in the film.
While PCB drilling is about repeatability and keeping the cost per piece as low as possible, the medical industry demands the uttermost precision for micro machining of implants. Typical materials such as titanium with its low heat conductivity and sintered CoCr which is very abrasive, demand coatings with high hardness, oxidation resistance, and premium adhesion. HiPIMS elevates Si-doped coatings – a chemical composition which is well tested in the medical industry – to the next level. The fine-grained structure of the film and the tunable intrinsic stresses allow for higher Si content and thereby higher hardness in mass production machining. HiPIMS metal ions follow the field lines and arrive perpendicular to the surface of the substrate for a homogeneous 3D coverage of the cutting tool. Controlling the HiPIMS pulse parameters effectively avoids excessive coating at the cutting edge or the tool tip – a typical issue for other PVD methods – for tighter tolerances in coating production.
HiPIMS, with its unique combination of favorable properties, opens new business opportunities in the growing market of precision and micro-machining.