Amorphous silicon & silicon nitride etching with NF3 DBD plasma

Summary form only given, as follows. Amorphous silicon (a-Si) and silicon nitride (SiNx) etching process using atmospheric pressure plasma has been studied. As etchant, a small quantity of NF3 was mixed to nitrogen based DBD (Dielectric Barrier Discharge) plasma for the thin film etching. Test specimen was processed by passing through the downstream plasma zone under the specially designed plasma module with the speed of 50 mm/sec and with 3 mm of module-specimen spacing. The net treatment size of the plasma module (i.e. size of plasma jet nozzle) was 410 mm in width and 0.7 mm in length. The etch rate of the both film was increased with applied power and NF3 flow rate in the range of 0∼3 lpm (liter per minute). The SiNx etch rate was dramatically increased by addition of oxygen at the elevated temperature with PR (Photo Resist) patterned specimen. At the optimized condition, the a-Si and SiNx etch rate was about 150 Å/scan and about 200 Å/scan at 50mm/sec scan speed, respectively. With PR patterned specimen the SiNx etch rate was increased about four times higher than the other case by addition of O2. In this experiment, the applied power range was 0.7∼1.6 kW. And the etch rate results of the both layer did not show plateau in that power range.