Patent ID: 7770478

Claim:
An apparatus for measuring a chuck attachment force, the apparatus comprising: a chuck configured to receive and attach a substrate thereto; a separating device that detaches the substrate from the chuck; a variable load applying device connected to the separating device, the variable load applying device operating the separating device by changing a load of the variable load applying device; and a controller that measures both a load of the variable load applying device when the substrate is attached to or contacts the separating device prior to detaching the substrate from the chuck and a load of the variable load applying device when the substrate is detached from the chuck, calculates a difference value therebetween, and determines a chuck attachment force using the difference value, wherein the separating device comprises: a lift device that detaches the substrate from the chuck; and a drive device that transmits a drive force to move the lift device, wherein the drive device comprises a power transmitting device that connects the variable load applying device to the lift device to transmit the drive force to the lift device, and wherein the power transmitting device comprises at least two pulleys and at least one power transmitting member coupled to the at least two pulleys.