The current state of the technologies of machining and processing of silicon wafers is described. The 8 inches diameter wafer process is just shifting to the process for 12 inches wafers. Actually, in wafer plants it is necessary to reconsider the wafer making methods which have been used so far. For instance, the method of wafer slicing is changing to multi-wire lapping from grinding with inner type thin diamond wheels, since the preparation of thinner and wider wheel metal plates becomes impossible for prospective large diameter silicon wafers. In wafer surface finishing, the present lapping and polishing methods will be replaced with a kind of grinding method using abrasive wheels as in glass lens manufacturing. However it might not become realistic soon, and, for the time being, the current conditions of lapping and chem-mechanical polishing will be utilized. The stock removing mechanism and the damaged layer in lapping or polishing are given an account.