U. Heydenreich¹, D. A. L. Loch¹, A. W. Oniszczuk², R. Bandorf³, A.P. Ehiasarian⁴, W. Gajewski^2
1Trumpf Hüttinger GmbH + Co. K.G, Freiburg, Germany
²Trumpf Huettinger Sp. z.o.o., Warszawa, Poland
³Fraunhofer Institute for Surface Engineering and Thin Films IST, Braunschweig, Germany
⁴Sheffield Hallam University, Sheffield, United Kingdom
Over the last 20 years, high power impulse magnetron sputtering (HIPIMS) has developed into a key PVD technology. It is primarily used in sputtering processes where customers' demands for film quality and characteristics cannot be met by any other means. HIPIMS has established itself as the state-of-the-art coating technology for smooth, highly resistant hard coatings on conductive substrates.
However, applications outside of hard and decorative coatings have only been able to establish themselves to a limited extent. There is a strong, growing trend towards using HIPIMS in more specialized areas, such as semiconductors and electronic packaging.
The pulsed generation of ionized species presents opportunities, but also challenges. In addition to generating ions, controlling them is also challenging. The quest for the ideal substrate bias is complicated by diverse ion-neutral ratios and higher ionized states in the metallic flux, especially given the changing HIPIMS process parameters. Nevertheless, there are various solutions available for generating the desired substrate bias, such as different pulse shapes and patterns, as well as their combination with other excitation methods, such as DC or RF. Applications in the semiconductor industry present particular challenges. Similar process modules must ensure consistent process quality throughout the entire target life. Special consideration must be given to the requirements regarding particle prevention. This discussion will present possible solutions to these challenges. The requirements for process qualification will also be addressed. Measurement technology is generally only used for process development. However, new requirements are also emerging for measurement technology. Any possible changes, for example due to target erosion or changes in ionization conditions, must be adequately compensated for.
In order to meet these special requirements, a deep understanding of the processes involved in coating three-dimensional structures, as well as their modelling and simulation, is necessary. Verifying stability over the entire target lifetime during development is very time-consuming. Qualifying the product is even more costly. Therefore, digital twins must be developed to shorten the qualification process.