<p>This study introduces a rapid, non-ablative methodology for determining the crystallographic orientation of thermally oxidized silicon wafers by exploiting nanosecond laser-induced plasticity at 1064 nm. Instead of relying on time-intensive electron backscatter diffraction (EBSD) or destructive wet etching, the approach leverages thermoelastic stress localization at the SiO<sub>2</sub>/Si interface to activate orientation-dependent slip-line networks. A coupled multi-scale thermo-elasto-plastic finite-element framework is developed to capture (i) seconds-scale baseline heating under high-repetition irradiation and (ii) superimposed nanosecond thermoelastic stress spikes that can reach the yield-onset condition while remaining below melting. The role of the oxide is quantified over a wide thickness range (10–500 nm), revealing a non-monotonic threshold behavior consistent with interference-controlled optical coupling. Infrared thermography delineates the wafer-preserving process window, indicating that defocused footprints used for slip generation (full width at half maximum, FWHM <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\approx\)</EquationSource> </InlineEquation> 333–519 <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\mu\)</EquationSource> </InlineEquation>m) remain well within sub-melting conditions. Optical and atomic force microscopy (AFM) reveal nanometer-scale step relief (<InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\le\)</EquationSource> </InlineEquation> 70 nm) with no evidence of melting pits, resolidification textures, or microcracks. The resulting morphologies—near-orthogonal grids on Si(100) and 60° triangular networks on Si(111)—follow the {111}⟨110⟩ slip systems and are reproduced under unpolarized irradiation, distinguishing them from polarization-governed laser-induced periodic surface structures (LIPSS). Fast Fourier Transform (FFT) analysis yields a dominant spatial periodicity of <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\({\Lambda}\approx0.97\mu\)</EquationSource> </InlineEquation>m. Crucially, hydrofluoric acid (HF) etching demonstrates that the step-like relief persists after oxide removal, evidencing slip within the underlying substrate. Repeatability tests across 10 wafers (100 sites) achieved a 98.5% success rate, supporting a practical, high-throughput metrology concept for in-line semiconductor orientation screening.</p>

Non-ablative crystallographic orientation determination of silicon wafers via nanosecond laser-induced plasticity

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发表日期：

2026年3月26日

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Tu Cong Huynh,
Anh Phuong Hoang

摘要

This study introduces a rapid, non-ablative methodology for determining the crystallographic orientation of thermally oxidized silicon wafers by exploiting nanosecond laser-induced plasticity at 1064 nm. Instead of relying on time-intensive electron backscatter diffraction (EBSD) or destructive wet etching, the approach leverages thermoelastic stress localization at the SiO₂/Si interface to activate orientation-dependent slip-line networks. A coupled multi-scale thermo-elasto-plastic finite-element framework is developed to capture (i) seconds-scale baseline heating under high-repetition irradiation and (ii) superimposed nanosecond thermoelastic stress spikes that can reach the yield-onset condition while remaining below melting. The role of the oxide is quantified over a wide thickness range (10–500 nm), revealing a non-monotonic threshold behavior consistent with interference-controlled optical coupling. Infrared thermography delineates the wafer-preserving process window, indicating that defocused footprints used for slip generation (full width at half maximum, FWHM \(\approx\) 333–519 \(\mu\) m) remain well within sub-melting conditions. Optical and atomic force microscopy (AFM) reveal nanometer-scale step relief ( \(\le\) 70 nm) with no evidence of melting pits, resolidification textures, or microcracks. The resulting morphologies—near-orthogonal grids on Si(100) and 60° triangular networks on Si(111)—follow the {111}⟨110⟩ slip systems and are reproduced under unpolarized irradiation, distinguishing them from polarization-governed laser-induced periodic surface structures (LIPSS). Fast Fourier Transform (FFT) analysis yields a dominant spatial periodicity of \({\Lambda}\approx0.97\mu\) m. Crucially, hydrofluoric acid (HF) etching demonstrates that the step-like relief persists after oxide removal, evidencing slip within the underlying substrate. Repeatability tests across 10 wafers (100 sites) achieved a 98.5% success rate, supporting a practical, high-throughput metrology concept for in-line semiconductor orientation screening.