SC-2 BASED PRE-THERMAL TREATMENT WAFER CLEANING PROCESS

摘要

Pre heat-treatment processing of a silicon wafer to grow a hydrophilic oxide layer includes an initial step of contacting the wafer with a pre-clean SC-1 bath, thereby producing a silicon wafer surface that is highly particle free. After a deionized water rinse, the wafer is scoured with an aqueous solution containing hydrofluoric acid and hydrochloric acid to remove metallic-containing oxide from the wafer surface. In order to grow a hydrophilic oxide layer, an SC-2 bath (containing hydrogen peroxide and a dilute concentration of metal-scouring HCl) is used. The resulting hydrophilic silicon oxide layer grown on the surface of the silicon wafer using the combined SC-1->AF/HCL->SC-2 wafer cleaning process has a metal concentration no greater than 1x109. The diffusion length of minority carriers is increased from a range on the order of 500-600 microns to a range on the order of 800-900 microns.