PPT Slide
Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
Previous Research - Baklanov et. al and Olim
Baklanov et al., “Limitation of HF-Based Chemistry for Deep-
Submicron Contact Hole Cleaning on Silicides,” J. of
the Electrochemical Society, Vol. 145, No. 9,
- Small geometry size effects of submicron trenches may retard
the cleaning of deep trenches.
- Interactions of process chemicals with target surface
chemistries (e.g. HF-SiO2) can produce smaller diffusivities.
- Trench solutions have colloidal as well as ionic characteristics.
Olim, Moshe, “Liquid-Phase Processing of Hydrophilic
Features on a Silicon Wafer,” J. of the
Electrochemical Society, Vol. 144, No. 12,
- Agrees with Nakao: Liquid flow only contributes to contaminant
rinsing times by providing greater concentration gradients at higher
- One order of magnitude change in diffusivity has a much greater
impact than a similarly sized change in fluid velocity.
- Within 100 ms the concentration at the base of a deep trench
(4 x 0.5 mm) is reduced by seven orders of magnitude.
Size effects in contact resistance in trenches cleaned
with HF solutions (Baklanov et al.)
Concentration dependencies in deep trench on
fluid velocity/diffusivity combinations (Olim)
u = 0.01 m/s, D=1.e-9 m2/s
u = 1.0 m/s, D=1.e-9 m2/s
Diffusion only, D=1.e-9 m2/s
u = 0.01 m/s, D=1.e-10 m2/s