Microwave plasma processing

Patent Granted To provide microwave plasma treatment equipment in which flow velocity of gas is suppressed. The microwave plasma treatment equipment 100 has a dielectric window constituted of a plurality of dielectric parts 31 transmitting a microwave through a slot antenna 30, a plurality of gas nozzles 27 fixed to the lower surface of a beam 26, a gas supply section for supplying predetermined gas, and a chamber U for treating a workpiece by generating plasma of the predetermined gas by the microwave transmitted the dielectric window. Each dielectric part 31 includes a first porous material 31Ph having a first porosity, and a second porous material 31Pl coupled with the first porous material 31Ph and having a second porosity lower than the first porosity.