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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.

A new approach is presented for resist strip after high-dose implantation of ultra-shallow extensions with minimal loss in the S/D area. For our work, solvents are selected in combination with physical force to remove the resist because of their excellent selectivity towards the sensitive USJ implanted substrates. To enable a more gentle physically enhanced strip of the crusted resist with less risk for damage and less residues left, a short oxidizing pre- and/or post-treatment has to be introduced. Wet O3-based cleans have limited efficiency while UV/O3-exposure and particularly a short plasma step are found to be beneficial. The effect of such an oxidizing treatment on the crusted resist and its removal is presented as well as the effect on highly doped substrates. It is shown that especially after NMOS implantation, a short oxidizing step results in better dopant retention during activation anneal due to the grown oxide.