Marcus Klein, Michael Hofmann, SURAGUS GmbH, Dresden, Germany
Vacuum deposition tools are workhorses that often operate far beyond their originally intended lifespan. Many fabs run equipment that is 20 years old or more. While the mechanical infrastructure remains sound, these legacy systems typically lack the inline metrology capabilities that modern Industry 4.0 manufacturing demands. Simultaneously, newly designed deposition systems often prioritize chamber throughput over integrated process monitoring which often is traditionally done offline. This creates a compelling opportunity: retrofitting both legacy and contemporary vacuum tools with non-contact sensor technology to enable real-time characterization of conductive thin films.
This paper presents novel integration strategies for eddy current sensors in vacuum coating equipment — from well-proven sputtering workhorses to state-of-the-art cluster tools. These systems deposit a wide range of conductive films: metals (Cu, Al, Ag, Au), barrier layers (Ta, Ti, W), and transparent conductive oxides (ITO, AZO). The non-contact approach delivers instantaneous sheet resistance, resistivity, or thickness data without affecting the coating or requiring offline test samples. .
We present three practical retrofit pathways: sensor integration in interconnection modules between existing chambers, installation within transfer valve assemblies, and deployment of dedicated metrology chamber modules that slot into established tool architectures. Each approach addresses vacuum environment realities such as UHV compatibility, thermal management, electromagnetic shielding, and space constraints while sharing practical insights on compensating for temperature and edge effects. For new system designs, we present optimized mounting concepts that enable metrology without compromising footprint or cycle time. .
The economics strongly favor inline integration. Conventional offline characterization introduces delays and consumes expensive monitor material. Inline eddy current sensors cost a fraction of offline metrology equipment and manual testing effort while delivering continuous data rather than periodic spot checks enabling immediate detection of process drift and higher confidence in coating quality. .
Extending the productive life of proven deposition tools by 5 to 10 years while adding modern process control capabilities delivers significant return on investment compared to complete system replacement. Application examples from production environments demonstrate how legacy tool retrofits achieve measurement performance comparable to dedicated offline systems, transforming aging but reliable equipment into Industry 4.0-ready production assets.