Smooth sailing for protective films
Moore's law, formulated about 50 years ago, states, generally, that the number of transistors on affordable integrated circuits will double approximately every 2 years. That has pretty much held true but, as transistors approach the atomic scale, the law is now approaching its limits, creating a barrier to development within the semiconductor industry. Thin films made from nanomaterials could provide a solution if their growth and interfacial stresses can be optimised. Protective oxides have several beneficial applications in this realm and were the focus of the EU-funded project 'Nano-scale protective oxide films for semiconductor applications & beyond' (NANO-PROX). One of the main targeted applications was chemical mechanical planarisation (CMP), a process used by semiconductor manufacturers to 'planarise' a macroscopically flat silicon wafer. Formation and removal of the metal-oxide thin films is critical to controlling defect parameters and resulting topography. NANO-PROX focused on meeting current and future CMP requirements. After establishing the CMP and surface chemistry facility, scientists first turned to technical developments for applications in the semiconductor industry. Experiments evaluated the effect of oxidiser type and oxidation time on the surface properties of thin films of both tungsten and germanium. In the second part of the project, researchers implemented CMP to induce self-protective metal-oxide nanofilms on titanium for orthopaedic implants. The team evaluated cell attachment and infection resistance. Another line of inquiry studied CMP-induced protective films on heating elements to enhance corrosion and lime scale prevention. Finally, scientists studied the use of metal-oxide nanofilms on aluminium for aeroplane bodies and landing gear to enhance corrosion resistance. The project's overwhelming success can be seen in the variety and number of publications, presentations, patent applications and new projects it spawned. Eight confidentiality agreements were signed with the private sector as well. NANO-PROX has contributed to the increasingly competitive position of the EU in CMP and metal-oxide thin-film technologies. The impact will be felt in sectors from biomedicine to semiconductors to aerospace, providing a potential boost to the EU economy in a period of economic crisis.
Keywords
Self-protective, thin films, oxide films, semiconductor, chemical mechanical planarisation
