| 摘要 |
An electrostatic chuck (230) for holding a device (200) includes a chuck body (244), a Coulomb electrode assembly (246), a Johnsen-Rahbek (J-R) electrode assembly (248), and a control system (224). The chuck body (244) includes a chucking surface (250) that engages the device (200), and the chuck body (244) is made of a dielectric having a relatively high resistance. The J-R electrode assembly (248) is positioned spaced apart from the chucking surface (250). The Coulomb electrode assembly (246) is also positioned spaced apart from the chucking surface (250). The control system (224) selectively directs a first voltage to the J-R electrode assembly (248) to generate a J-R type force that attracts the device (200) towards the chucking surface (250), and selectively directs a second voltage to the Coulomb electrode assembly (246) to generate a Coulomb type force that also attracts the device (200) towards the chucking surface (250). With this design, both the J-R type force and the Coulomb type force are used to concurrently attract the device (200) against the chucking surface (2500. As a result thereof, the electrostatic chuck (230) is better able to reduce non-flatness of the device (200), and/or crush any particles positioned between the device (200) and the chucking surface (250). |
