This paper introduces a new AI-enpowered method for accurately measuring submicron structures with high aspect ratios (HAR) in semiconductor packaging using spectral scatterometry across DUV, visible, and SWIR wavelengths. By optimizing polarization and spectrometer calibration, the method improves spectral signal contrast for precise critical dimension (CD) metrology. An Artificial Neural Network (ANN) tackles phase shift problems for trench spacings near light wavelengths, enabling precise CD measurement. Experiments demonstrate DUV light's proficiency in measuring small CD differences and VIS and SWIR's effectiveness for larger, deeper structures. The DUV system measures HARs up to 10:1 and apertures down to 0.46 μm with accuracy within 3% of Focused Ion Beam/Scanning Electron Microscope (FIB/SEM) comparisons.
This research means to solve the challenges in measuring deep high-aspect-ratio (HAR) and thin-film structures in 3D integrated circuits. As the semiconductor industry reaches its physical limitations in device scaling, advanced technologies such as advanced lithography and packaging have become crucial in extending Moore's law. This has led to the use of denser nano-to-sub-micron structures in three-dimensional integrated circuits (3D-IC), resulting in smaller, more functional devices. However, measuring these complex and deep HAR and thin-film structures with a large depth range from a few nanometers to a few hundred micrometers using a single optical system is challenging. To address this need, this article presents an AI-guided scatterometry method using numerical aperture control to achieve a large measurement range. The system uses broadband light to generate multi-wavelength reflection responses from the samples. With the help of an electromagnetic simulation tool and an artificial neural network model, the depth resolution can be improved through inverse modeling. The results demonstrate the ability to measure a wide range of samples with depths ranging from nanometers to micrometers scale, including sub-micron HAR openings and ultra-thin films, as long as the measurement bias is controlled within acceptable limits.
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.