PURPOSE: To improve the yield of a probe inspection by inserting and disposing the probe of a prober system which measures the electrical characteristics of substrates after an etching treatment into a preliminary chamber at the time of sending the substrates via the preliminary chamber into a treatment chamber and etching the substrates.

CONSTITUTION: The substrates 1 (high-frequency SAW devices, etc.) with which a photoetching stage is completed are set in a cassette 8 in a cassette chamber 7. The substrates 1 are transported from the cassette 8 into the preliminary chamber 5 by opening a sluice valve 9 and are subjected to the characteristic inspection by the contact of the prober system 6 when the treatment chamber 4, the preliminary chamber 5 and the cassette chamber 7 are evacuated to a vacuum. The substrates 1 are transported to the treatment chamber 4 and are treated for a prescribed period of etching time in the case of execution of a frequency adjustment again when the result of the inspection is NG. The substrates 2 are transported to the cassette chamber 7 when the substrates satisfy specifications after the treatment. The substrates are returned to the treatment chamber 4 unless the substrates satisfy the specifications. As a result, the characteristics after the etching are evaluated in a short time and the efficiency is improved.