Search

Dynamics of the evaporative drying of ultrapure water (UPW) droplets on a hydrophobic Si surface in a controlled ambient is studied. A quantitative study of the watermarks (WM) residue volume and mass is performed from low to high ambient humidity. The effects of oxygen in the gas phase and dissolved O2 concentration in UPW are investigated for different levels of ambient humidity. The shape of the drying residue on surface is studied to estimate the mechanism of residual colloids/particles deposition in presence of different ambient conditions. Our quantitative study on WM formation in different ambient humidity showed a linear increase in drying residue mass as a function of the initial UPW droplet volume.

In this work a methodology and metrology for the Si substrate loss characterization during cleaning and etching of Si semiconductor substrate has been developed. Using this methodology, the substrate loss in different HF based cleaning solutions can be investigated, both in situ and ex situ. The etching mechanism in different HF mixtures is studied, where the effect of dissolved O2, illumination, free F-ions and additives can be explored. Etch rates are determined ex situ by measuring the Si concentration as function of time with Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). By combining both electrochemical and ICP-MS data, the number of electrons n involved in the electron transfer reaction are determined both in darkness and illumination. Results confirm the existing Si etching mechanism under illumination, with n=2. It is shown that in darkness a low etch rate is observed, and even under deoxygenated HF conditions pointing to some chemical etching mechanism.