To achieve high accuracy and precision in optical metrology for advanced semiconductors, it is crucial to identify and compensate for errors from optical components and environmental perturbations. In this study, we investigated the sources of the errors in the interferometric ellipsometer developed for next-generation OCD. The objective lens and beam splitters, the critical optical components of the system, are intensively investigated. The system errors induced by temperature fluctuation, wavelength inaccuracy, and defocus were quantitatively examined. We also proposed methods for compensating individual errors and analyzed the effect of the compensation. As a result of error compensation, the accuracy and precision of the system is improved by 6.9 times and 2.3 times, respectively. Although the investigation was conducted based on our interferometric ellipsometry system, the finding is not limited to this system, as these errors are commonly found in most optical metrology systems. The proposed method for error compensation will be essential strategies for various ellipsometry systems suffering from a low level of accuracy and precision.
We present advanced application of novel ellipsometry technique, referred to as self-interference pupil ellipsometry (SIPE), integrating self-interference and pupil microscopy to overcome the sensitivity limitations raised from the conventional spectroscopic ellipsometry. We investigated various samples including a SiO2 monolayer, grating patterned wafers, and DRAM wafers to demonstrate outstanding capability of SIPE for metrology. The angular range corresponds to approximately 5,000 acquisition of conventional ellipsometry tools with 2º angular step scanning. From the experimental results and simulation, we expect the sensitivity of SIPE for structure metrology is at least 0.15 nm at a single wavelength and even better for multispectral measurements.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.