Electrodeposition Techniques in Microelectronics Metallization

Electrodeposition has become the cornerstone of metallisation in advanced microelectronic manufacturing, enabling the controlled growth of conductive films and interconnects within ever-shrinking feature sizes. By adjusting parameters such as current density, potential waveform and electrolyte composition, electrodeposition delivers uniform, void-free fillings of high-aspect-ratio features including through-silicon vias (TSVs) and damascene trenches. Key to this control are organic additives—suppressors, accelerators and levelers—that modulate local deposition rates to achieve bottom-up or superconformal growth and to prevent defects. Integration into three-dimensional packaging and multilevel interconnect architectures further demands attention to adhesion, mechanical stress and warpage, alongside throughput requirements met by high-speed and galvanostatic processes. Recent advances have elucidated additive-surface interactions at the molecular level, while simulation enables prediction of current and species distributions in complex geometries. Together, these developments underpin reliable copper, cobalt and gold metallisation for leading-edge logic and memory devices worldwide.

Research from Nature Portfolio

Investigations of the electrochemical performance and filling effects of suppressor, accelerator and leveler combinations have revealed how competitive and synergistic adsorptive behaviour governs void-free TSV metallisation. By mapping displacement sequences and surface coverages, studies have optimised additive concentrations to deliver uniform bottom-up copper deposition under varying potentials. In dynamic filling experiments, staged electrodeposition at different current densities demonstrated that low, medium and high currents yield distinct defect modes—seam, defect-free and void-filled respectively. Analysis of additive consumption, ion diffusion and local deposition kinetics pinpointed the conditions for defect-free filling and clarified how geometrical constraints influence morphological evolution within deep vias.

Research from all publishers

A high-speed electrodeposition method has been developed for copper pillar fabrication, combining scanning electron microscopy, electron backscatter diffraction and finite-element modelling to correlate current density profiles with crystallographic texture and mechanical adhesion to build-up films. Separately, microfluidic studies of suppressor and leveler adsorption have shown that sequential and co-addition regimes result in surface replacement dynamics critical for initiating bottom-up deposition in damascene trenches. Further work on gold superconformal filling has employed micromolar bismuth accelerators in sulfite electrolytes, demonstrating that hydrodynamic shear controls accelerator coverage and thus local deposition rates, enabling void-free trench filling over a defined potential range.

Electrodeposition Techniques in Microelectronics Metallization publication trend

The graph below shows the total number of articles in electrodeposition techniques in microelectronics metallization across all publications each year (not limited to Nature Index journals).

Technical terms

Electrodeposition: A process by which metal ions in an electrolyte are reduced at a cathode under an applied electrical current or potential to form a solid metallic layer.

Through-silicon via (TSV): A vertical conductive pathway etched through a silicon wafer, used to achieve three-dimensional integration in microelectronic packages.

Suppressor: An organic additive that adsorbs onto the cathode surface to slow metal deposition uniformly and prevent premature closure of recessed features.

Accelerator: A chemical species that selectively increases the local reduction rate of metal ions, promoting rapid filling in desired regions.

Leveler: An additive that preferentially adsorbs at protrusions to reduce deposition there, ensuring planarisation and minimising surface roughness.

Bottom-up filling: A metallisation strategy in which deposition commences at the base of a cavity and progresses upward, avoiding trapped voids.

Superconformal deposition: A regime in which depressed regions of a patterned surface receive enhanced metal flux, leading to void-free filling of trenches or vias.

References

1. Raman and QCM Studies of PPG and PEG Adsorption on Cu Electrode Surfaces. Journal of The Electrochemical Society (2018).
2. Mechanism of Cobalt Bottom-Up Filling for Advanced Node Interconnect Metallization. Journal of The Electrochemical Society (2018).
3. Bottom-up Filling of Damascene Trenches with Gold in a Sulfite Electrolyte. Journal of The Electrochemical Society (2018).
4. Dynamic through-silicon-via filling process using copper electrochemical deposition at different current densities. Scientific Reports (2017).
5. Investigations of the electrochemical performance and filling effects of additives on electroplating process of TSV. Scientific Reports (2020).
6. High-speed electrodeposition for Cu pillar fabrication and Cu pillar adhesion to an Ajinomoto build-up film (ABF). Materials & Design (2021).
7. Warpage Analysis of Electroplated Cu Films on Fiber-Reinforced Polymer Packaging Substrates. Polymers (2015).
8. Transitional Additive Adsorption with Co-Addition of Suppressor and Leveler for Copper TSV Filling. Journal of The Electrochemical Society (2020).
9. Galvanostatic Plating with a Single Additive Electrolyte for Bottom-Up Filling of Copper in Mesoscale TSVs. Journal of The Electrochemical Society (2018).