PARTICLE DEPOSITION CONTROL FOR VARIOUS WAFER SURFACES IN ACIDIC SOLUTION WITH SURFACTANT

Particle deposition control for various substrate surfaces was studied using acidic solution with surfactant. It has been demonstrated that particle deposition onto the various substrate surfaces in the chemicals depends on the zeta potential of particle and of the substrate surface. An anionic surfactant addition is found to make both particles and the substrate surface negatively charged, while a cationic surfactant addition is found to make both of them positively charged. The surfactant addition, therefore, can suppress particle deposition onto the substrate surface even when some particles remain in the chemicals. When some chemical is carried over to the subsequent ultrapure water rinsing bath, this chemical carry-over triggers particle deposition in the ultrapure water rinsing stage when a cationic surfactant is used or when a hydrophilic surface is used. However, this phenomena is not observed when an anionic surfactant is used. These results suggest that an anionic surfactant is effective in suppressing particle deposition onto the various wafer surfaces in acidic solutions.