releasing metal contaminants be not disposed in a space between the supply outlet 23 and the wafer 4 in case the gas manifold 7 b is made of a metal e g stainless steel the metal contamination of the wafer can be significantly reduced by positioning the active species supply outlet 23 of the discharge tube 16 inside the reaction tube 11 as shown in fig1 fig1 exemplifies a schematic cross sectional side view of a reaction chamber 1 and a plasma source 2 of a semiconductor manufacturing apparatus in accordance with a ninth embodiment of the present invention in the drawing the reference numeral 1 represents a reaction chamber 6 a gate valve airtightly separate the reaction chamber 1 from the transfer chamber 8 a a reactive gas inlet to the reaction chamber 1 9 a an exhaust port of the reaction chamber 1 4 wafers 2 a plasma source of the icp type 16 a discharge tube of the plasma source 2 116 a gate valve between the reaction chamber and the plasma source 2 8 c a reactive gas inlet to the plasma source 2 20 rf generator 114 and 115 pressure gages and 118 pressure balancing valve in the apparatus in accordance with this embodiment the plasma source 2 is arranged outside of the reaction chamber 1 i e it is of a remote plasma type as in the previous embodiments a gas is supplied to the plasma source 2 and excited therein thereafter active radicals generated in the plasma source 2 are supplied to the reaction chamber 1 and reacted with the wafer 4 to be treated the reaction chamber 1 is of a hot wall.