Yuji Fukazawa

Wet Cleaning (Part 2): Removal of Metallic Contaminants

To remove metallic contaminants from the surface of silicon wafers, a combination of acidic mixtures, such as HF solution, H2SO4-H2O2 mixture, and HC1-H2O2 mixture (SC-2), and alkali mixtures, such as NH4OH-H2O2 (SC-1), is being used at present.

The Influence Of Native Oxide On Si Wafer Cleaning

A method has been developed for removing metallic contaminataminants such as Cu which have a lower ionization tendency than Si and easily adhere Si surfaces in HF solution. Copper removal by a mixture. of acids and hydrogen peroxide can be described in terms of a corrosion model based on the pH-electrochemical potential diagram. This model suggests that HCl/H202 and HF/H202 sholuld remove Cu contaminants from Si surfaces. However for these solutions, the Cu removal efficiency is affected by the growth of native oxide before cleaning.