Single-additive TSV filling achieved with a tris-ammonium-based suppressor

• A single-suppressor electrodeposition process enables defect-free TSV filling. • Single-suppressor gap-filling overcomes the limitations of typical three-additive methods. • A triazine-core molecule with three ammonium side chains is designed for TSV filling. • Selective breakdown of the suppressor at the TSV bottom promotes extreme Cu filling. • A bottom-up filling mechanism is suggested by the behavior of the synthesized suppressor. As transistor scaling approaches its physical limits, advanced semiconductor packaging has emerged as a promising solution by enabling system-level integration and supporting the More-than-Moore paradigm. One of the most critical aspects of semiconductor packaging is the formation of high-quality metal interconnections that can reliably connect multiple dies. Cu electrodeposition has become increasingly important due to its ability to fabricate complex interconnect structures without defects. These processes typically rely on multiple organic additives in the electrolyte, whose multiplicity increases cost and complicates process control. In this study, we present a newly designed organic suppressor for single-suppressor through-silicon via (TSV) filling via Cu electrodeposition. The molecule, composed of a triazine core linked to three ammonium-based side chains, is engineered to provide strong suppression while enabling mass-transfer-limited adsorption along the TSV depth. The differing time constant of the electrical versus mass transport response gives rise to the negative differential resistance behavior and the corresponding spatial bifurcation into active and passive regions. When coupled with the reentrant TSV geometry, such bifurcation results in extreme bottom-up filling. The new tris-ammonium-based suppressor and associated design strategy expand the range of molecule functionality and geometry that can be used in next-generation Cu electrodeposition processes.