High-fidelity chip delayering using green (515 nm) femtosecond lasers

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Accurate semiconductor chip metal layer reconstruction is crucial for hardware support, validation, and analysis.
• Conventional methods like mechanical polishing, chemical etching, and focused ion beam (FIB) delayering are slow, inconsistent, and resource-intensive.
• Existing laser delayering methods face challenges with selective material interaction and uneven ablation.

Purpose of the Study:

• To develop a streamlined, efficient, and reproducible method for semiconductor chip delayering.
• To investigate the use of a green (515 nm) laser for improved chip layer removal.
• To enhance high-fidelity chip analysis for diagnostics and reverse engineering.

Main Methods:

• Developed a streamlined approach combining laser-based delayering with high-resolution multimodality microscopy.
• Investigated and optimized the use of a green (515 nm) laser for chip delayering.
• Performed comparative imaging using confocal microscopy and scanning electron microscopy (SEM), with energy-dispersive X-ray spectroscopy (EDS) for material analysis.

Main Results:

• Achieved significantly cleaner delayering and improved exposure of underlying chip structures using the green laser.
• Demonstrated reduced sensitivity to material variations, enabling more uniform and controlled layer removal.
• Observed notable improvements in layer clarity and significant debris reduction compared to conventional methods.

Conclusions:

• The green laser delayering method provides a more efficient and reproducible alternative to conventional techniques.
• This approach enhances the quality of chip analysis, offering potential for high-fidelity diagnostics and reverse engineering.
• Optimized green laser parameters lead to superior layer clarity and minimal debris, advancing semiconductor analysis workflows.