A high aspect ratio (> 15:1), sub-micron, deep capacitor trench process is demonstrated in an 8 inch Applied Materials P5000E magnetically enhanced reactive ion etcher (MERIE) using HBr/NF3/He-O2 chemistry. Through the insertion of ferro-magnetic sheet material into the pedestal, sub-micron trenches can be etched to depths greater than 10 micrometers , with etch rates > 6000 angstroms/min, uniformity < +/- 5%, profile uniformity 89 +/- 0.5 degree(s) and selectivity to oxide > 40:1. The importance of the wafer surface temperature on trench etch properties is established. Studies indicate that there is a threshold temperature below which the chosen recipe would need to be modified to produce satisfactory trenches.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.