Colloquia

Summary

In the last couple of years, the demand for high performance chips has increased significantly. Chips need to have more processing brainpower, use less energy, and have higher performance while also keeping their small size. The only way to do this is to print smaller, such that more transistors can be packed on the same chip surface area. To achieve this, high-resolution Extreme Ultraviolet (EUV) lithography technology is currently under development.

Developments for the new generation high-resolution EUV lithography machines are currently being made at VDL ETG in Almelo. Here modules are assembled that will be the base for these EUV machines. On these modules, cooling circuits are assembled that need to meet very tight leak tightness specifications to guarantee sufficient lifetime of the machine. The leak tightness specification that is needed for these modules, is about 4·10-10 mbar·L·s-1. In comparison,  ranges from 10-10 mbar·L·s-1 and below are seen as “absolutely leak tight”, meaning nothing can leak through. To create low leak rate connections, VCR (Vacuum Coupling Radiation) connections are used. These connections use metal-to-metal sealing. During the development stage, these connections are not becoming leak tight the first time. Within the research, the connections and influences during assembly are examined  to look into the causes of leaks. Based on the findings, a suitable FTR (First Time Right) assembly strategy for the connections is set up to create a trustworthy assembly process for the connections. Next to this, a suitable leak testing strategy is set up to manage trustworthy detection of low leak rates for the connections. This is done to increase assembly and test efficiency for when series production will begin.

Within the research, the connections have been examined, and a suitable tightening strategy has been identified. Next to the tightening strategy that was found, key influences during assembly have been identified to significantly influence the potential leak tightness of the connections. These mainly being bending influences that are introduced during the installation procedure on the modules. When these are prevented, and installation is done using the new tightening strategy, a FTR assembly will be possible. After installation, the connections are tested using a new leak testing strategy. Helium leak testing is used, able to detect the required leak rates as low as 4·10-10 mbar·L·s-1.