ICMCTF2011 Session G6: Advances in Industrial PVD & CVD Deposition Equipment

HIPIMS has entered the industrial production in 2010. Thus the R&D efforts split into supporting the daily production of mostly nitride based films and the search for new application areas using more complex coatings as oxides.

The first commercial job coating HIPIMS film for cutting tools is been used for more than half a year when the ICMCTF 2011 takes place. This presentation will summarise the experiences of this first large scale use of HIPIMS: What advances of the HIPIMS coating machine are the result of this production use? What applications benefit most from this novel technique? What issues require intensified R&D? What about the economical aspects of HIPIMS? Is there a sensible return of investment for the user?

Cathodic arc discharge (CAD) is a high current – low voltage point discharge and characterized by a localized discharge that is large current of thermal electrons are emitted from small (10um square) cathode spots. Due to this unique discharge nature, a high degree of ionization of target materials, as well as high evaporation rate can be achieved. These characteristics make the CAD process very attractive for industrial application, in spite of the apparent drawback of CAD process that is MPs. On the other hand, conventional magnetron sputtering is a low current - high voltage planar discharge and the ionization of the target material is quite low, usually in the order of a few percent and the plasma is mainly consisting of gas ions. The HIPIMS process is also a planar discharge process like conventional sputtering. However, momentarily input power is approximately 3 orders magnitude higher and a number of reports indicate that significant amount of metal ions exist in the plasma. In spite of the apparent drawback of HIPIMS, the deposition rate, this process is gaining a lot of attention because it seems like that this process promises MPs free arc-like coatings which is critical for certain tribological applications.

Different types of nitride coatings including standard TiN and TiAlN were deposited by industrial arc ion plating (AIP), a new nearly droplet free arc technology, recently introduced by Kobe Steel and HIPIMS. TiAlN coatings deposited by the HIPIMS process show strong preferred (111) orientation and a relatively high hardness up to 35 GPa is obtained. Whereas AIP TiAlN coatings are is characterized by a moderate hardness up to 30 GPa and (200) or nearly random orientation at an equivalent substrate bias condition. Cross sectional TEM observations of both coatings revealed that HIPIMS coatings show smaller grain sizes compared to AIP coatings. High magnification image, many lattice defects can be observed for HIPIMS coating and is hardened by many atomic defects, possibly highly stressed.

R&D centres are more and more developing in cooperation with the industry. Therefore the need for robust multi-functional R&D equipment with full scale industrial production potential has risen.

The Hauzer Flexicoat^® 850 is a versatile machine with a modular set-up. The system is equipped with four interchangeable chamber walls, which means that the machines can be upgraded with new technology at any time. It is a hybrid machine, which can combine technologies such as arc, sputter, HIPIMS, HIPIMS⁺, PACVD, dual magnetron sputtering and plasma-nitriding in one machine.

The machine is often used for developing tribological coatings in automotive markets and development of decorative and tool coatings. The combination of technologies is used to create multi-layers on products without breaking the vacuum between processes or to create multi-composite coatings.

Technologies will be discussed in combination with machine design and up-scaling of processes to industrial production levels. Furthermore a method for lowering development costs will be introduced. Special R&D cathodes will result in more flexibility and lower target material costs.

It has been developed as the answer to market demand to limit arc energy during an arc occurrence in sputtering. Industrial realization has been successfully employed in air cooled DC power supplies successful on the market for years already. Possibility of using DC power supplies for sputtering highly arcing materials is a result of this. It is a beginning of new age in magnetron sputtering technology. Further improvement and optimization by using more efficient water cooling and the fastest MOSFET transistors, results in the new generation of power supplies with state-of-the-art arc management parameters. Comparison of standard and state-of-the-art arc management solution in sputtering power supplies will be presented, along with experimental results for TCO materials.

Increased loads (mechanical loads, thermal loads, etc.), longer life time, higher performance and thus higher productivity, reduction of weight and friction as well as the improvement of corrosion resistance are demanded for innovative tools and components to meet functional and decorative requirements. In particular, surface treatments and related coating technologies are selected in the day-to-day mass production of precision components in order to provide application specific surface solutions. Advanced coating systems offer multiple solutions to meet these demands. The four basic processes used for coating systems are: arc evaporation, magnetron sputtering, PA-CVD and nitriding. Some development streams have to be noticed: the arc evaporation process was progressively improved; the traditional magnetron sputtering is extended to the high current pulsed sputtering, PA-CVD mainly used for a-C.H:X coatings (X = Si, O …) has been upgraded to deposit high performance coatings; the duplex process plasma nitriding and PVD was introduced in industrial scale. Application tailored hybrid and duplex technologies provide the chance to synthesize the next generation of high performance PVD coatings. With the hybrid technology materials can be combined wisely nearly without limits.

The potentials of the advanced PVD-systems, the hybrid PVD technology and the duplex treatment will be illustrated. First coating solutions from latest approaches to hybrid processes that combine sputtering and arc technology as well as from duplex processing with a combination of nitriding and PVD will underline the leading edge technology presented.

Two difficulties commonly are associated with the industrial deposition of ta-C by these technologies: (1) a limited control and long-term stability of the arc sources and (2) an emission of particles and droplets leading to a high coating roughness. By controlling the pulsed arc discharge by a laser (Laser-Arc) an efficient tool for a long-term stable and efficient working carbon plasma source for ta-C deposition was obtained. The graphite cathode is designed as a rotating roll and placed in a separate source chamber (Laser-Arc-Module / LAM). This module is combined by an adapting flange with the industrial batch coater DREVA 600. A Q-switched Nd-YAG-Laser is used for the temporally and locally controlled arc-ignition while the ta-C deposition mainly originates from the pulsed arc discharge parameters. This combination of LAM with industrial coaters also opens new opportunities to design new generations of coating stacks incorporating super hard top-layers in combination with classical and proofed interface designs and hard coatings. In the final version the adapting flange is replaced by a novel filtering unit. Now, the industrial coating of parts and tools with smooth and virtually defect-free ta-C coatings becomes possible with this new equipment.

The InlineCoater 300 is a high yield multifunctional PVD deposition system equipped with four process chambers, including a load-lock with fast evacuation time (~20s). This, combined with high deposition rate coating sources, results in a system suitable to produce a high number of different coatings within a short time frame. The above allows using the system for development as well as up-scaling and high volume production, thus enabling a short industrialization process. Moreover, the system is generic and well suited both for different deposition techniques (e.g. arc evaporation, magnetron sputtering) and reactive processes.

The high capacity of the system has been demonstrated applying the concept of Design of Experiments (DOE). The material system used as a model system was the Ti-N-C, deposited by reactive cathodic arc evaporation. The parameters explored were: arc current, substrate bias voltage, partial pressures, and ratios of the reactive gases. In order to cover a relevant parameter space, more than 100 depositions was carried out within one day. The resulting coatings, which were grown to a thickness of approximately 1 µm were evaluated with respect to color, as defined by the L*a*b*-space.

The resulting model derived from the regression analysis of the measured L*a*b*-data was used to predict the full L*a*b*-space of the Ti-C-N-system with respect to the input parameters. The model could also be used for compensation of time-dependent drift, ensuring stability during a production cycle.