In a slide fastener, a fastener tape is woven with a single-woven structure, and in the fastener tape, a double-woven region woven with a double-woven structure is formed along a tape longitudinal direction. Such increased strength is necessary when dealing with the heavier and larger boards typically used in stand up paddle boarding. The degree of charge-up induced at the surface of the wafer by the plasma used during the plasma process is determined from the change in the amount of collected secondary electrons.