The continued trend of Moore’s law relies on Chemical Mechanical Planarization (CMP) to attain angstrom-level uniformity for advanced integrated circuit (IC) designs. CMP processes utilize complex colloid dispersions (i.e., slurries) containing surface-active chemistries that lead to the culmination of surface defects (i.e., organic residues) that require p-CMP cleaning mediation. Due to the continued miniaturization and advanced packaging requirements of IC devices, p-CMP cleaning methods aim to reduce the prevalence of primary defects without the proliferation of secondary defect modes (i.e., corrosion). Current strategies in p-CMP cleaning processes aim to manipulate the 3-body interface (i.e., brush-defect-chemistry) to initiate defect-chemistry-surface interactions. To date, successful methods in p-CMP cleaning processes implement an “undercutting” mechanism as the predominant mode of residue removal however, this mode of removal induces the incidence of corrosive events. Therefore, this work focuses on the development of a “softer” approach to Cu p-CMP cleaning by surveying various additives (i.e., α,β-unsaturated carboxylic acids, carboxylic acids, and unsaturated benzaldehydes) to exploit an “overcutting” mode of organic residue removal. By implementing additional modes of interaction (i.e., π-stacking, H-bonding, conformational relationships, etc.), the mode of residue removal can be finely tuned to achieve desired surface-active conditions. This work employs a suite of techniques (i.e., Tafel analysis, OCP vs. Time, SEM, white light interferometry, and PSD analysis) to correlate structure-activity to organic residue removal efficiency and the effects on shear force, particle removal efficiency, and the generation of secondary defectivity. Initial results have shown that implementing an “overcutting” mechanism will decrease the overall shear force to significantly reduce the proliferation of p-CMP cleaning defects. Furthermore, adding ancillary structure activity aids in additional modes of residue interaction to alter removal at the liquid-brush interface. Additionally, increased structure activity has shown the promotion of residue-chemistry interactions to form a secondary passivation layer. Moreover, conformational changes that result in limited accessibility to the α,β-unsaturated double bond promote an “undercutting” mode of removal to become the predominant mode of organic residue mediation.

Exploring structure-activity effects while employing an “overcutting” mode for organic residue removal during Cu post-chemical mechanical planarization (p-CMP) cleaning

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