METHOD OF RELEASING SPECIMEN ATTRACTED BY ELECTROSTATIC ATTRACTION

摘要

PROBLEM TO BE SOLVED: To prevent a wafer from getting out of position and being chipped by a method wherein a step that the wafer is slightly pushed up and kept stationary after it is subjected to plasma processing is repeatedly carried out, and the wafer is released from a specimen base by its reaction force. SOLUTION: When a reverse voltage is applied to a specimen base to carry out an electrostatic attraction release treatment after a plasma etching process is carried out many times, parameters such as voltage and the like optimal for an attraction release treatment are changed. Therefore, a wafer 19 can not be released in some cases. In this case, a push pin 18 is made to ascend by a height which can be set by a parameter and kept stationary for a time set by the parameter. The periphery of the wafer is separated off by the reaction force of the wafer 19 in a time when it is kept stationary. The push pin 18 is made to ascend by a step and kept stationary for a time to release the periphery of the wafer 19 further by the reaction force. The wafer 19 is surely released taking advantage of its reaction force without getting out of position.