Non-destructive thickness measurement of Si wafers via optical third-harmonic generation with femtosecond laser pulses
Year: 2024
Type: article
Abstract: • High-precision, non-destructive thickness measurement method using surface-sensitive optical third-harmonic generation • Sub-10 nm measurement precision • Sub-100 nm measurement uncertainty for the certified thickness reference sample • A high depth-selectivity enabling stacked wafers’ defect detection • A universality for various transparent wafers, such as MgO or sapphire wafers Si wafers are vital substrate materials in semiconductor manufacturing and require precise non-destructive thickness measurements. However, the conventional electrical and optical measurement techniques are limited by depth selectivity and system complexity. Here, we propose a simple, high-precision, non-destructive thickness measurement method based on surface-sensitive optical third-harmonic generation at both sides of Si wafers. We irradiated a highly stabilized near-infrared femtosecond pulse laser with a broad spectrum and central wavelength of 1550 nm on the Si wafers, which are non-transparent in the visible to ultraviolet wavelength range. Using the proposed system, the thickness of the certified reference wafer was measured, yielding results that fall within the certified uncertainty.
Source: Results in Optics
Institution: Korea Advanced Institute of Science and Technology
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,230
OpenAlex ID: W4403935472