Optimizing XRF wafer metrology beyond toolmatching
X-ray fluorescence (XRF) analysis is a key component of wafer metrology, a critical process for ensuring the performance and reliability of semiconductor devices. As the challenges faced by the semiconductor industry evolve, XRF wafer metrology must keep up.
Here, we will explore the latest innovations in XRF wafer metrology, focusing on how the industry is moving beyond toolmatching to optimize system- and fab-level performance.
Industry challenges
The semiconductor industry faces a number of challenges when it comes to XRF wafer metrology, including different substrates, result variation across tools and fabs, and thinner layers down to 2D materials. Matching metrology tools, automatic quality monitoring, and sensitivity are all critical considerations. So, what are some of the best ways to overcome these challenges and ensure your fab is ready for the industry’s future?
The 2830 ZT wafer analyzer
A comprehensive solution can be found with the 2830 ZT wafer analyzer, which covers all the industry challenges above. It offers XRF analysis in the range of 0.2 nm – 10 μm and can handle any flat substrate up to 300 mm in diameter. The 2830 ZT is fully automated, cleanroom compliant, and is the most stable solution for your fab.
Improving signal-to-background
Once your instrumentation is in place, the next goal is software optimization. First up is DifferAction, a software solution that helps to optimize your tool according to your existing and future needs, enabling enhanced performance by reducing diffraction effects and minimizing result variation. A 14-day variation test with no drift correction applied, using the Boron Combi channel and 200-second measurement times, has shown minimal result variation. Precision results have also been achieved with 100-second measurement times and 50 repetitions over a period of two months.
ToolMatch software
Every semiconductor process today relies on multiple instruments for metrology, and ToolMatch software helps you to manage them efficiently. This software enables you to get nearly identical results on multiple tools, improving accuracy across your set-up. In our example, the relative difference was reduced from 1-4% to 0.00-0.30% – comparable to the measurement error on a single tool.
ToolMatch is easy to use and offers automatic updates by measuring a dedicated set of ‘ToolMatch’ wafers. This not only saves time, but also reduces the need for additional personnel in the cleanroom.
Internal cassette
Finally, an extra hardware solution: an additional internal cassette with up to 25 slots for quality check wafers, monitor wafers, and ToolMatch reference wafers. Using this additional cassette makes your process much more efficient by enabling scheduled application monitoring, which saves you time and means one fewer person entering the cleanroom.
Conclusion
XRF wafer metrology is a critical component of the semiconductor industry, and as industry challenges continue to evolve to the monolayer level, so must the solutions used to address them. The latest innovations in XRF wafer metrology help to save time, keep cleanroom personnel to a minimum, and improve accuracy and precision across tools and fabs.
In particular, semiconductor manufacturers looking to optimize their XRF wafer metrology will benefit from the complete solution offered by the 2830 ZT wafer analyzer, which covers all industry challenges and is the ideal choice for a smarter, more efficient, and more future-ready fab.
Further reading