Process for Etching Thermally Produced Oxide Layers on Semiconductor Wafers and Substrates
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
For increasing the etch rate, impurity ions are implanted into the front side of the oxidized wafer. This increases the etch rate by a factor 8 to 20. As a result, it is possible to use HUANG A (NH4OH H2O2) to remove the oxide layer from the front side of the wafer, yielding a surface of very high quality. Apart from this, it is no longer necessary to apply photoresist to the rear side of the wafer due to the high selectivity of the etch rates between thermally generated oxide layers with and without subsequent implantation. Thus, a process which previously required five steps is reduced to 1. thermal oxidation of both wafer sides at 950ŒC, 2. implantation of impurity ions into the front side of the wafer, and 3.