The principle of inductively coupled plasma (ICP) and perspective of ICP development are reviewed. Multispiral coil ICP (MSC-ICP), which has the advantages of low inductance, high efficiency, and excellent uniformity, is discussed in detail. Applications to thin film processing technologies and the future prospects of ICP are also described.

The authors have developed a new inductively coupled plasma source (ICPS), using a multispiral coil with 1/3 the inductance of the conventional ICPS coil. This source can produce plasma of 1011 cm−3 or higher density with ±5% fluctuation, at pressures below 10 mTorr.

An atmospheric line-shaped microplasma source was developed for fine pattern etching, and the dependence of the etching properties on the substrate temperature and the distance between the two outer gas outlets was investigated. There was a sudden increase of the etching rate and a decrease of top width when the substrate temperature was 300°C or more. Auger electron spectroscopy (AES) analysis indicates that oxidation on the line shoulder caused the top width to decrease. By decreasing the distance between the two outer gas outlets from 3 mm to 650 µm, the top width decreased from 441 µm to 234 µm. The gas flow simulation result revealed that there exists a firing limit of SF6 partial pressure from 0.1% to 0.2% in the configuration.

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