Within the 24 months on EIC program, WOOPTIX has realized the implementation of a complete lab and fab tool, achieving related goals in mechanics, optics, electrics, electronics, assembly, and data analytics developed in coordination with a system-engineering approach and reaching the precision of 3.16 nm measuring a 300 wafer in a fully automated fab tool The method has been validated by ASML which outcomes have been published in a co-shared paper.
Requirements analysis and overall system architecture design have been leading to the general high-level engineering design with the purpose of deeply defining specific systems areas with mechanical CAD, Optics Zemax models, Electrical & electronic CAD and Executable Software Code.
At lower level, it has been Design and implemented the Mechanical Stability Frame with Vertical Wafer Holder, Design the lens holders, camera holders, linear stage holder, vibration isolation (bread board), grounding of the system (the frame needs to be grounded so close collaboration with electrical engineer on where to have direct contact to the frame and where to apply paint). It also included the design of an electronics rack for where the electronics boxes from the electrical engineer will be placed. The mechanical design has also to be done in close collaboration with the optical engineers as the lens locations and camera locations designed into the system at very specific locations determined by Zemax simulations.
The custom lens has been designed and simulated to work with each specific sensor and wafer setup. Software engineering has been dedicated to the implementation of algorithms and the graphical user interface. There are specific algorithms implemented on how to calculate roughness and nanotopography.
The assembly and testing went through the big challenge of installing the large lens, calibrate the system, which involves small adjustments to the lens orientation and the camera location, while taking a lot of images using a standard mirror surface instead of a silicon wafer. The testing by running standard samples and known samples (silicon wafers, or FPDs we have run in the past with known data sets) and stakeholders sample has provides repeatability and reproducibility results.
The final implementation of new the vertical clamped frame in the fab tool allowed to reach a precision of 3.16 nm.To check the repeatability of the system, according to semiconductor repeatability standards, the measurements have been repeated 30 times, calculating peak-valley and RMS values.
