NOVELTY - The apparatus has a high frequency antenna (11) generating an inductively coupled plasma in a plasma generation region in processing chamber (5). A metal window (3) is provided between the plasma generation region and the high frequency antenna, where the metal window is firstly divided into sections (3a1, 3a3) that are electrically insulated from each other by a line along a peripheral direction of the window. The window is secondly divided into sections (3b1, 3b3) that are electrically insulated from each other by lines along directions crossing with the peripheral direction.    USE - Inductively coupled plasma processing apparatus for performing plasma processing i.e. etching of an oxide film, an indium tin oxide (ITO) film and a metal film, in forming a thin film transistor on a substrate i.e. glass substrate, which is utilized in a flat panel display (FPD) e.g. LCD, electro luminescence (EL) display and plasma display panel, and a solar cell panel. Can also be used for performing plasma processing on a semiconductor wafer.    ADVANTAGE - The apparatus suppresses interference between the eddy current circulating in a loop that is generated in a inner metal window arranged below an inner high frequency antenna and the eddy current circulating in another loop that is generated in an outer metal window arranged below an outer high frequency antenna, thus suppressing the intensity variation of the inductive electric field generated in the processing chamber, and hence improving controllability of the plasma distribution in the processing chamber. The apparatus reduces generation of the vertical electric field in the processing chamber and the consumption of the metal window, and avoids decrease in the production efficiency of plasma sources.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of an inductively coupled plasma processing apparatus.    Airtight main vessel (1)    Metal window (3)    Sections (3a1, 3a3, 3b1, 3b3)    Plasma chamber (5)    High frequency antenna (11)