Methods of conditioning interior processing chamber walls of an etch chamber are described. A fluorine-containing precursor may be remotely or locally excited in a plasma to treat the interior chamber walls periodically on a preventative maintenance schedule. The treated walls promote an even etch rate when used to perform gas-phase etching of silicon regions following conditioning. Alternatively, a hydrogen-containing precursor may be remotely or locally excited in a plasma to treat the interior chamber walls in embodiments. Regions of exposed silicon may then be etched with more reproducible etch rates from wafer-to-wafer. The silicon etch may be performed using plasma effluents formed from a remotely excited fluorine-containing precursor.