Inductively coupled plasma source with internal straight antenna

An inductively coupled plasma source with an internal straight antenna was developed. By inserting an antenna into plasma, the induction of a strong e lectric field in the plasma and the efficient transmissions of power to pla sma is enabled. However, there was a practical problem in that antenna sput tering occurred. Suppression of antenna sputtering and methods of insulatin g the antenna were studied. Consequently, it was found that sputtering impu rities were reduced by covering the straight antenna with a quartz pipe. Fu rthermore, the amount of quartz pipe etching could be reduced to as little as 1/10th the original value. As a result of fabricating and evaluating the plasma source in which four straight antennas were arranged in parallel, e lectron density was determined to be as high as 10(11) cm(-3) even at a pre ssure as low as 4 mTorr. When the processing performance of the plasma sour ce was evaluated, the ashing rate of the photoresist and the etching rate o f the poly-Si were, respectively, 4.8 mum/min and 450 nm/min. These values are at practically applicable levels.