The Behavior of Surfactant Adsorption and Minimization of Particle Contamination in HF Solution

摘要

In this study, we observed the zeta potentials of Si, SiO_2 and Si_3N_4 surfaces and polystyrene latex (PSL) and A1_2O_3 particles in HF-H_2O solution with surfactant. Furthermore, particle deposition prevention onto above surfaces in HF-H_2O solution by adding surfactant was investigated. The zeta potentials in HF solution were not different from the results of measurement in HC1 solution especially in the case of adding surfactant. It has been demonstrated that the surfactant adsorption onto wafer surface is different by hydrophilic or hydrophobic property and zeta potential of wafer surface, namely the results are hereinafter described; 1. hydrophobic surface: the surfactant molecules are easily adsorbed. 2. hydrophilic surface: the hydrophilic parts of ionic surfactant molecules which have different polarity from the zeta potential of wafer surface are adsorbed onto wafer surface and the polarity of zeta potential is inverted. Furthermore, it was demonstrated that the particle deposition onto wafer surfaces was dependent on the both surfaces property(hydrophobic or hydrophilic) as well as zeta potential and van der waals potential. When the both surfaces were hydrophobic, the particles easily deposited onto the wafer surface, even if the zeta potentials of both surfaces were same polarity. However, the particle deposition was minimized when the both surfaces were controlled to be hydrophilic by adding the anionic surfactant more than CMC. In this case, the zeta potentials of both surfaces were controlled to be same polarity.