METHOD OF INTRODUCING LATTICE DEFECT FOR GETTERING OF IMPURITY ATOM INTO BACK SURFACE OF SEMICONDUCTOR WAFER

摘要

PURPOSE:To introduce lattice defect without leaving contamination sources, by ejecting ice particles, and making them crash against the back surface of a semiconductor wafer. CONSTITUTION:From a supplying source 2, liguid N2 3 is introduced into a vessel 1, which is filled up to about half depth, and N2 gas with a specified flow rate is blown via a heat exchanger 5 to generate waves of several mm on the liguid surface. Pure water with a specified pressure and a flow rate is sprayed together with N2 gas to form ice particles 8, which are conveyed to a hopper 10. With the N2 gas having a specified high pressure and a flow rate, the ice paricles are ejected at a rate of 0.3 l/min, and made Crash against the back surface of a wafer to introduce lattice defect. As the fine ice particles are used, particles or cut-off powder acting afterwards as contamination sources do not remain. When ice particles made of a water wherein CO2 gas is contained in super pure water and the specific resistance is equal to or lower than 1MOMEGA.cm are used, the possibility of attraction of contamination substances due to electrostatic charge at the time of ejection impact can be avoided.