New measurement technique cuts errors in next-gen semiconductor manufacturing
Researchers have developed a more accurate way to measure silicon carbide chip layers—a critical material for electric vehicles and power electronics. The advance cuts measurement errors in half, potentially reducing costly defects in high-stakes manufacturing environments where precision directly affects device performance and profitability.
Originaltitel: Accurate infrared interferometric thickness measurement of Silicon carbide epitaxial layers using dynamic refractive index correction
Silicon carbide (SiC) epitaxial layers are critical components in wide-bandgap semiconductor devices, where precise thickness measurement is essential for performance and reliability. Conventional infrared interferometry typically assumes a constant refractive index, leading to systematic errors due to material dispersion and carrier effects. This study proposes a physics-consistent framework that integrates Sellmeier dispersion theory with the Drude model to establish a dynamic refractive index for SiC. An analytical thickness expression is derived, reducing relative error by 2-5% and decreasing systematic deviation from 3-5% to 1-2% compared with fixed-index methods. To improve spectral peak extraction, an enhanced FFT-based approach incorporating Hanning windowing, zero-padding, and multi-band partitioning is developed. Measurements at incident angles of 10 degrees and 15 degrees yield consistent thickness estimates, with weighted averaging further improving stability. For multi-beam interference, a compensation strategy based on Fabry-P & eacute;rot theory is introduced and validated using silicon reference samples, achieving a thickness of 3.981 +/- 0.013 mu m and reducing systematic error by 10-15%. Comparative results demonstrate that the proposed method achieves lower systematic error (1.1-1.8%) and improved multi-angle consistency, indicating its effectiveness for high-precision thickness metrology and its applicability to other semiconductor and thin-film materials.