Patent ID: 9581641
Date: 2017-02-28
CPC Classifications: G01R

Claim:
1. A wafer inspection apparatus comprising: 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 chuck top on which the wafer is mounted to face the probe card; a vacuum mechanism configured to evacuate a sealable surrounding space surrounded by the chuck top and the probe card to a set pressure to allow or maintain a predetermined pressure-contact state between the probe card and the wafer, wherein the vacuum mechanism includes: a vacuum source; an electropneumatic regulator having a proportional control valve having a first port connected to the vacuum source and a second port connected to the surrounding space, a pressure sensor configured to measure a pressure in a predetermined gas channel or a space which is sealed and connected to the second port, and a valve control unit configured to control the proportional control valve such that a pressure measured by the pressure sensor becomes close to or equal to the set pressure in response to an electrical signal instructing a desired set pressure; and a gas channel network configured to be switched between a first mode in which the second port of the proportional control valve is connected to the surrounding space via the pressure sensor and a second mode in which the second port of the proportional control valve is connected to the surrounding space and the pressure sensor is connected to the surrounding space in parallel with the proportional control valve.