Dynamic through-silicon-via filling process using copper electrochemical deposition at different current densities

Area of Science:

• Materials Science
• Electrochemistry
• Microelectronics Engineering

Background:

• Through-silicon-via (TSV) technology is crucial for advanced semiconductor packaging.
• Achieving void-free and defect-free TSV filling remains a significant challenge.
• Electrodeposition is a primary method for TSV metallization.

Purpose of the Study:

• To investigate the dynamic through-silicon-via (TSV) filling process.
• To determine the effect of varying current densities on TSV morphology and filling quality.
• To understand the underlying mechanisms governing TSV filling during electrodeposition.

Main Methods:

• Staged electrodeposition experiments were conducted at controlled current densities (4, 7, and 10 mA/cm²).
• Morphological analysis of TSV filling was performed for each current density.
• Filling coefficients were analyzed to understand the interplay of ion diffusion and additive consumption.

Main Results:

• Low current density (4 mA/cm²) resulted in seam defect filling.
• Medium current density (7 mA/cm²) achieved defect-free TSV filling.
• High current density (10 mA/cm²) led to void defect formation.
• Current density influences TSV filling through coupled additive and copper ion dynamics.
• Local deposition rates are modulated by the geometric features of the plating surface.

Conclusions:

• Current density is a critical parameter for controlling TSV filling quality in electrodeposition.
• Optimizing current density enables the prevention of common defects like seams and voids.
• The findings provide insights into the electrodeposition mechanisms for advanced microelectronic packaging.