Correlation between Copper Precipitation and Grown-In Oxygen Precipitates in 300 mm Czochralski Silicon Wafer

The behaviors of copper (Cu) precipitation along the radial direction of the 300 mm Czochralski grown silicon wafer have been investigated. It is found that the density of Cu precipitates decreases from the center to edge of the silicon wafer. Moreover, it is revealed that the density of grown-in oxygen precipitates also decreases along the radial direction as mentioned above. Therefore, it is apparent that the Cu precipitate density is positively correlative to the grown-in oxygen precipitate density. This is due to that the grown-in oxygen precipitates can serve as the heterogeneous nucleation centers for Cu precipitation. It is suggested that the Cu decoration in combination with preferential etching can be used to indirectly evaluate the radial distribution of grown-in oxygen precipitates in the silicon wafers.