To efficiently process a semiconductor substrate having a large diameter by a small-sized and power-saving semiconductor processor.

A semiconductor processor comprises an antenna 1 which radiates microwaves from microwave sources 4a and 4b via an introduction window 5 of a vacuum container 8 into the vacuum container 8, and a plurality of magnetic field generators 42, which are arranged on one surface of the antenna 1 and which respectively generate a magnetic field vertical to the introduction window 5. The directions of lines of magnetic force respectively generated by adjacent magnetic field generators 42 are opposite to each other. In this case, a microstrip antenna, with radiation elements between the respective magnetic poles of the magnetic field generators 42 and the introduction window 5, is employed as the antenna 1. More preferably, the microwaves irradiated from the respective radiation elements are clockwise circularly polarized waves with respect to the directions of the lines of magnetic force of the corresponding magnetic poles.