Inductively coupled plasma source using internal multiple U-type antenna for ultra large-area plasma processing

An inductively coupled plasma source with internal-type linear inductive antennas named as "internal multiple U-type antenna" was developed for the substrate size of 2300 × 2000 mm² and the characteristics of the large-area inductive plasma source were investigated. High density plasmas on the order of 1.18 × 10¹¹ cm^-3 could be obtained at the pressure of 15 mTorr Ar gas and the RF power of 8 kW with good plasma stability. In addition, by using variable capacitors at the end of the antenna, lower antenna voltage and more uniform antenna voltage distribution could be obtained. When a photoresist film was etched using O₂ plasma with 8 kW RF power, an etch uniformity less than 11% could be obtained using the multiple U-type antenna on the substrate size larger than 7th generation (2 200 × 870 mm²).