PURPOSE: To increase the electric conductivity and the thermal conductivity of a semiconductor wafer, and improve the uniformity on the semiconductor wafer in a treatment using a high frequency power supply, by a method, after a conducting layer is formed on the rear of a semiinsulative semiconductor wafer, the treatment of the semiconductor wafer is performed by using the high frequency power supply.

CONSTITUTION: Photo resist is spread on a GaAs wafer 1. Exposure and development are so performed that the photo resist 3 is left on a region 2a where a conducting layer is not formed. A window is opened only on a region 2 where the conducting layer is formed. After Si is implanted in a GaAs wafer 1 by ion implantation method, Si is implanted from the rear, in order to form a conducting layer 4. The GaAs layer 1 is annealed, after an SiN film is formed on both surfaces of the GaAs wafer 1 in order to prevent As in the GaAs wafer in which Si is implanted from scattering. After annealing, the SiN film is eliminated. Thereby, the uniformity of treatment is improved, the characteristics of a semiconductor integrated circuit is increased, and the manufacturing yield is improved.