ICMCTF2008 Session G7: Advances in Industrial Deposition Equipment and Metrology for Coatings and Thin Films

Triple Coatings are built from 3 layer blocks:

- Adhesion layer (usually pure Ti-N, Cr-N)

- Conventional core layer(s) with monolayer, gradient, or nanolayer structures (usually CrTiN, AlTiN, AlCrN or AlTiCrN) and

- Superhard nanocomposite toplayer (usually TiAlN/SiN or AlCrN/SiN)

The paper introduces and compares different coating machine concepts to realize different Triple Coatings in the range of Ti-Cr-Al-C-Si-N by rotating cathodes without target exchange. The comparison of the different configurations will be carried out according to the following criteria:

- Flexibility and modularity for using the machines in small and medium size enterprises

- Deposition rate with the help of computer simulation

- Micro and nano structure of the deposited layers with the help of computer simulation

The results of the computer simulation will be compared to practical deposition rates and structures realized by existing machine configurations.

The new Flexicoat 850 platform is a very flexible concept offering arc and sputter combinations as well as PA-CVD capabilities. The Flexicoat 850 can be dedicated for tool coatings in the form of the Rapid Tool Coater (RTC), which offers a high quality and cost effective deposition of the standard tool coatings like AlTiN. In an another configuration, the Flexicoat 850 can be configured into a Rapid Ring Coater (RRC), dedicated for extreme high efficiency and low cost deposition of piston rings. A newly developed arc evaporator with very high target utilisation has been developed for this purpose. As a third possibility, the Flexicoat 850 platform can be used for R&D purposes with very flexible configuration options, where arc, sputter and PA-CVD capabilities can be combined into one machine.

As a detailed example, the Rapid Ring Coater (RRC) is studied and technical data and performance of the machine concept is presented.

For many years intensive research work was done to deposit hard and wear resistant alumina based coatings by physical vapor deposition. However most research groups focused on conventional reactive sputtering technology with the drawbacks of poor productivity, poor reproducibility and difficult process control. A breakthrough was achieved by Oerlikon Balzers with the development of the P3e (tm) Technology (Pulse Enhanced Electron Emission), which overcomes the difficulties of reactive sputtering for the formation of oxide based coatings. Already at deposition temperatures below 600°C hard alumina coatings can be deposited at a deposition rate comparable to nitride based coatings.

A new batch type coating system (INNOVA) was presented end of 2006, which is the first eqiupment for industrial scale production of alpha alumina based coatings (P3eTM technology). In this discourse an experience report on more than one year production with this coating system will be given.

Independent of the development of new coatings a continuous development of the coating technique is strived for by most of the machine manufacturer. After the full automation of the machines and monitoring of all important process data was accomplished, a higher flexibility - to be prepared for the deposition of new coatings and for the implementation of new or improved technologies - as well as a better efficiency - to do the whole coating procedure more economic - is now in the centre of interest.

By means of the dual cathode technique (two neighboring circular cathodes) introduced in 1995 in indus-trial coating machines by EIFELER, the deposition of multilayered coatings could be done without loss of deposition rate. By that way, also the design of gradual transitions between two film compositions be-came easily possible. In comparison with large area rectangular cathodes that are considered to be domi-nant in the future, the circular cathodes seem to be the more cost effective ones. Especially when consid-ering the change of coating material for development purposes (e.g. when investigating new coating compositions) the material costs are much less. Also regarding the rate of deposition, a set of circular cathodes can usually be run at much higher currents than the appropriate large area rectangular cathodes what results in a higher rate of deposition. The circular cathodes have even essential future potential. So in the new configuration of machines, it will be possible to use pure metals to be evaporated from and mixed in front of the cathodes to generate the desired composition of the coating. This technique reduces the target costs essentially and leads additionally to improvements of the wear protecting properties of the coatings. Other minor developments are related to the deposition of basically smoother coatings. By well-directed poisoning of the cathodes a remarkable reduction in droplet emission can be reached resulting in a very smooth and dense coating. As a side effect, a reduced consumption of target material can be recognized what gives rise to an appropriate reduction in target costs per cycle. Another advantage of that technique is the increased rate of deposition. First tests with taps coated by that technique resulted in 30 - 50% higher performance due to the improved smoothness and density of the coatings.

Techniques related to the in-situ preparation of the substrates help also to improve flexibility and effi-ciency as well as the performance of tools. A special kind of in-situ plasma nitriding technology developed in the last years preserves the smoothness and shininess of the tool surface when increasing the surface hardness and corrosion resistance of the substrate material.