Charging-damage-free phi0.05 mum SiO2 contact etching in a pulsed C2F4/CF3I plasma has been successfully done. The SiO2 etching rate in C2F4/CF3I pulsed plasma did not decrease even for the pulse-OFF time of 20 mus. The C2F4/CF3I pulsed plasma generated a large amount of negative ions when the pulse-OFF time was increased. These results suggest that these negative ions would enhance SiO2 etching in the pulsed C2F4/CF3I plasma. Under these conditions, the phi0.05 mum SiO2 contact etching in the pulsed C2F4/CF3I plasma was observed as in the continuous plasma etching method. Additionally, the charging damage was drastically decreased in the pulsed C2F4/CF3I plasma because the negative ions in the pulsed C2F4/CF3I plasma reduced the accumulating charge on the substrate. These results imply that the negative ions generated in C2F4/CF3I plasma are very effective for charge-free and precise SiO2 etching.