The development of a large-area plasma source with high density plasmas is desired for a variety of plasma processes from microelectronics fabrication to flat panel display device fabrication. In this study, a novel internal-type linear inductive antenna referred to as "double comb-type antenna" was used for a large-area plasma source with the substrate area of 880 mm x 660 mm and the effect of plasma confinement by applying multi-polar magnetic field was investigated. High density plasmas on the order of 3.2 x 10(11) cm(-3) which is 50% higher than that obtained for the source without the magnetic field could be obtained at the pressure of 15 mTorr Ar and at the inductive power of 5,000 W with good plasma stability. The plasma uniformity < 3% could be also obtained within the substrate area. When SiO2 film was etched using the double comb-type antenna, the average etch rate of about 2, 100 angstrom/min could be obtained with the etch uniformity of 5.4% on the substrate area using 15 mToff SF6, 5,000 W of rf power, and -34 V of dc-bias voltage. The higher plasma density with an excellent uniformity and a lower rf antenna voltage obtained by the application of the magnetic field are related to the electron confinement in a direction normal to the antenna line.