DEEP TRENCH ETCHING METHOD TO REDUCE/ELIMINATE FORMATION OF BLACK SILICON

摘要

In a method of etching a wafer to form a DT (deep trench) in a plasma reactor, wherein the wafer temperature is greater than the cathode temperature, the improvement of conducting etching to reduce or eliminate "black silicon", comprising:a) providing a plasma etch reactor comprising walls defining an etch chamber; b) providing a plasma source chamber remote from and in communication with the etch chamber, and a wafer chuck or pedestal disposed in the etch chamber to seat a wafer; c) forming a plasma within the plasma source chamber and providing the plasma to the etch chamber; d) supplying RF energy to etch the wafer to a point where the wafer temperature is greater than the cathode temperature; and e) increasing the flow rate of fluorine species near the end of the DT process to provide the isotropic component needed to widen the CD.