Brittle fracture studied by ultra-high-speed synchrotron X-ray diffraction imaging

Area of Science:

• Materials Science
• Solid Mechanics
• Crystallography

Background:

• The Smart Cut process utilizes a weakened buried layer to enable layer transfer in silicon.
• Understanding crack propagation dynamics is crucial for optimizing semiconductor manufacturing.

Purpose of the Study:

• To investigate ultra-fast crack propagation in silicon single crystals during the Smart Cut process.
• To analyze the influence of microcracks on macroscopic crack front behavior.
• To provide a comprehensive view of controlled fracture in crystalline materials.

Main Methods:

• Utilized megahertz X-ray diffraction imaging with synchrotron radiation for *in situ* observation.
• Studied crack propagation along the (001) plane of silicon single crystals.
• Measured instantaneous crack velocities and analyzed post-crack movements.

Main Results:

• Observed crack propagation at speeds up to 2.5 km/s.
• Confirmed that microcrack distribution does not affect the macroscopic crack front shape.
• Identified local heating effects from the X-ray beam on crack velocities.
• Explained post-crack wafer part movements using pneumatic and elastic principles.

Conclusions:

• Provided direct confirmation of crack behavior in the Smart Cut process.
• Demonstrated the feasibility of *in situ* ultra-fast strain field measurements.
• Offered insights into controlled fracture mechanics in crystalline materials.