An internal-type linear inductive antenna, referred to as a “double comb-type antenna,” was used as a large area plasma source with a substrate size of 880×660mm2 (fourth generation glass size). The effects of the dual frequency (2 and 13.56MHz) radio frequency (rf) power to the antenna as well as the power ratio on the plasma characteristics were investigated. High-density plasma on the order of 1.7×1011cm−3 could be obtained with a dual frequency power of 5kW (13.56MHz) and 1kW (2MHz) at a pressure of 15mTorr Ar. This plasma density was lower than that obtained for the double comb-type antenna using a single frequency alone (5kW, 13.56MHz). However, the use of the dual frequency with a rf power ratio of approximately 1(2MHz):5(13.56MHz) showed better plasma uniformity than that obtained using the single frequency. Plasma uniformity of 6.1% could be obtained over the substrate area. Simulations using FL2L code confirmed the improvement in the plasma uniformity using the dual frequency to the double comb-type antenna.

A large area (1020mm×830mm) inductively coupled plasma (ICP) source has been developed using an internal-type linear antenna with permanent magnets forming a multicusp magnetic field. The large rf antenna voltages, which cause the electrostatic coupling between the antenna and the plasma in a large area internal-type linear-antenna ICP source, were decreased significantly by applying the magnetic field near and parallel to the antenna. Through the application of the magnetic field, an approximately 20% higher plasma density, with a value of close to 1.0×1011cm−3 at a rf power of 2000W, and about three times higher photoresist etch rates were observed, while maintaining the plasma nonuniformity at less than 9%.

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An internal-type linear inductive antenna, that is, a double-comb-type antenna, was developed for a large-area plasma source having the size of 1020mm×830mm, and high density plasmas on the order of 2.3×1011cm−3 were obtained with 15 mTorr Ar at 5000 W of inductive power with good plasma stability. This is higher than that for the conventional serpentine-type antenna, possibly due to the low impedance, resulting in high efficiency of power transfer for the double-comb antenna type. In addition, due to the remarkable reduction of the antenna length, a plasma uniformity of less than 8% was obtained within the substrate area of 880mm×660mm at 5000 W without having a standing-wave effect.