Comprehensive characterization of TSV etching performance with phase-contrast X-ray microtomography

Area of Science:

• Materials Science
• Semiconductor Manufacturing
• Metrology

Background:

• Reliable evaluation of through-silicon vias (TSVs) is crucial for 3D integrated circuits.
• Existing methods lack deterministic and 3D morphological characterization of via formation.
• The Bosch process for TSV etching requires precise control and analysis.

Purpose of the Study:

• To develop a highly sensitive phase-contrast X-ray microtomography approach for comprehensive TSV reliability evaluation.
• To provide quantitative characterization of TSV etching performance.
• To enable accurate 3D microstructure analysis for finite element modeling.

Main Methods:

• Utilized phase-contrast X-ray microtomography with recorrection of abnormal projections.
• Employed linear interpolation of neighboring projections to replace abnormal data.
• Applied phase-retrieval algorithms to distinguish silicon-air interfaces.
• Performed statistical analysis of 3D profile errors and parameter consistency.

Main Results:

• Achieved high accuracy in obtaining etch profiles, including diameter, bottom curvature, depth, and sidewall angle.
• Quantitatively characterized the 3D microstructure of vias.
• Provided statistical analysis of sidewall profile errors and inter-via parameter consistency.
• Generated datasets applicable for finite element analysis.

Conclusions:

• The presented X-ray microtomography method offers a robust tool for TSV etching characterization.
• The technique enables detailed 3D analysis critical for TSV reliability and 3D ICs.
• This general method has broad potential applications in semiconductor research and development.