Patent ID: 9689916
Date: 2017-06-27
CPC Classifications: G01R

Claim:
1. A method for determining a set value of a pressure for inspection in a wafer inspection apparatus including: a probe card having a plurality of contactors to be respectively brought into contact with a plurality of electrodes formed on a surface of a wafer as an inspection target; a movable chuck top configured to mount the wafer thereon to face the probe card; and a vacuum mechanism configured to control a pressure in a surrounding space sealable between the chuck top and the probe card to a predetermined set value of a negative pressure for inspection in order to generate or maintain a press-contact state between the probe card and the wafer by a predetermined pressing force, the method comprising the steps of: (a) evacuating the surrounding space by the vacuum mechanism and measuring, as a reference pressure, a highest negative pressure in the surrounding space which is obtained when the chuck top floats; (b) obtaining, as a reference height position, a height position of the chuck top which corresponds to the reference pressure; and (c) decreasing a pressure in the surrounding space to a level lower than the reference pressure, measuring the pressure in the surrounding space when the chuck top reaches a target height position obtained by adding a preset overdrive amount for the press-contact state between the probe card and the wafer to the reference height position, and setting the measured pressure as the set value of the pressure for inspection.