Damage Reduction in Reactive Ion Etching by Power Reduction
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Reactive ion etching (RIE) is one of the most critical processes in very large-scale integrated circuit manufacture. CF4 + H2 is useful in RIE because it gives a high etch rate ratio of silicon dioxide versus silicon. However, an undesirable damage layer of silicon is always formed on the silicon. This damage layer is harmful on device yield and on performance. The role of H2 in the formation of this damage layer formation is physical in nature and very similar to that of the low energy ion implantation. By reducing the power level in the RIE system, one can reduce the amount of damage significantly. For example, by dropping the power from 400 watts to 200 watts or power density from 0.35 W/cm2 to 0.18 W/cm2 one reduces the amount of damage, such that the leakage current is lowered by one order of magnitude.