AN IMPROVED PROCESS FOR THE FABRICATION OF SMOOTH VERTICIAL SIDE WALLED DEEP TRENCHES {110} ORIENTATION SILICON WAFERS USEFUL FOR MAKING SEMICONDUCTOR DEVICES.

摘要

An improved process for the fabrication of smooth vertical side walled deep trenches in (110) orientation silicon wafers useful for making semiconductor devices, which comprises cleaning silicon wafers using conventional methods, depositing on the cleaned wafer thin films of silicon dioxide followed by silicon nitride using known methods, depositing another layer of thin film silicon dioxide, etching the said pattern in the underlying layers of silicon nitride and silicon dioxide by known methods, removing top silicon dioxide layer by known methods, subjecting the above said patterned wafers to wet etching at constant temperature in the range of 85-95° C for a period ranging 1-2 hours to attain the requisite depth, removing the residual silicon nitride and silicon dioxide layers, cleaning thoroughly and drying the resultant etched wafers by known methods.