It is a patented dynamic electro-mechanical shield. It operates as an add-on for industrial facilities performing thin films deposition via Physical Vapour Deposition techniques (PVD). The smart shield collects the flux of wasted materials during the production of the thin-film (the overspray) just like any other shield. However, it is also capable of collecting different materials on different surfaces, addressing the most common issues of employing multi-purpose chambers: cross-contamination among different depositions, the tendency to flaking and difficulty in the recovery of wasted materials from the various layers that would deposit on top of each other when adopting a usual static screen. As a highly customized product, it is designed tailoring user needs and existing equipment. The adoption of a dynamic shield enables a whole new method for the maintenance and recovery process, which skips some of the most polluting phases. The first installations provided encouraging results and the concept has been awarded a few prizes.
Its main aspects are:
Targets chambers dedicated to multiple materials.
Enabling customers to reclaim up to ≈60% of the precious material not deposited on samples/products, already after the cleaning of the dynamic screen.
High purity of the materials recovered already after the shield cleaning step (up to 99.85%, potentially to be refined in further steps).
Dramatic reduction in the material recovery cost (down to -70%).
Fast cleaning process (down to -25% of traditional sandblasting for hard/thick coatings).
An environment-friendly process, that involves no aggressive solvents and can be potentially performed in-situ.
In multi-material chambers, a reduction in flaking phenomena increases the time interval between maintenance procedures. The smart shield is installed inside the vacuum chamber of the thin-film deposition facility: given its modularity, it is adaptable to different kinds of vacuum chambers. The core components of the system are removable blades, made of vacuum compatible metals, and covered on both sides with the cleaning promoter. The evaporated metals are recovered from the blades, instead of condensing on internal static surfaces of the vacuum chamber, where they are hard to remove. The multiple rotation stages of the blades permit to differentiate among different materials already during the production process. The system can be interfaced with the control electronics of pre-existing equipment in order to fully automatize it. When maintenance is performed (coinciding with the end of the blades’ lifetime), the smart shield has been able to collect a uniform layer of at least one target material, deposited on one side of the blades. The number of sides used depends upon the number of different valuable materials evaporated in the same chamber. On the other side(s), multiple layers of disposable materials may be present. Assigning different materials to the different sides of the screen may be also dictated by either lattice mismatch (to prevent flaking), either cross-contamination concerns. The target material can be easily recovered by wet-etching the cleaning promoter underneath. Compared with other processes, the material obtained after the cleaning of the screen is almost uncontaminated by other materials adopted in the chamber, nor by silicides that intervene in sand/bead blasting processes.