Unraveling the Underlying Mechanism of Polymer Swelling for Fluoride-Assisted Etching of Silicone Residues in Wafer-Level Packaging
발표자
임지수 (인하대학교)
연구책임자
윤창민 (인하대학교)
초록
내용
In wafer-level packaging (WLP), the effective removal of residual polydimethylsiloxane (PDMS) or silicone-based polymers after the temporary debonding process is critical for ensuring process reliability. This study presents a novel silicone etchant that operates through a polymer swelling-assisted mechanism. Five linear alkanes (pentane, hexane, heptane and octane) are selected as swelling solvents based on their close solubility parameter to PDMS. These solvents are systematically combined with tetrabutylammonium fluoride (TBAF) and a polar co-solvent (NOP), and the TBAF concentration is optimized in the range of 1.0–5.0 wt%. An optimized formulation composed of 3.0 wt% TBAF, 70.0 wt% pentane, and 27.0 wt% NOP achieves an etching rate of 96.4 µm/min, which is more than 12 times faster than that of a commercial silicone etchant. The enhanced etching efficiency is attributed to the swelling of the silicone matrix, which facilitates the diffusion of fluorine into the polymer network. Furthermore, material compatibility tests confirm that the etchant does not damage sensitive polymers such as PSPI and PSR used in pattern wafers and PCB substrates. This approach provides a highly selective, efficient, and polymer-safe solution for silicone residue removal in advanced semiconductor packaging applications.
- 본 연구는 2025년도 정부(교육부)의 재원으로 한국연구재단의 지원을 받아 수행된 기초연구사업임(RS-2022-NR070869).