Controlling Dielectric Constant and Breakdown Voltage for Optimizing Chucking Force in 3D-Printed Electrostatic Chucks: A Combined Simulation and Experimental Investigation

Electrostatic chuck (ESC) is used to adsorb objects such as semiconductor wafers and LCD panels using electrostatic force and is attracting great attention as a device that can compensate for the shortcomings caused by mechanical clamps or vacuum chuck. The ESC is composed of an insulating layer (body), a dielectric layer, and an electrode in which the electrode is formed in a bi-polar type and interdigitated pattern. The chucking force is known to be enhanced by maximizing the dielectric constant and breakdown voltage of the dielectric materials. However, it is difficult to find a single material that simultaneously exhibit both required characteristics. In this study, distinct materials were selected for the body and dielectric layer of the ESC. Two different ceramic composite resins were formulated by varying the contents of BaTiO₃ (BTO) and Al₂O₃ (Alumina) between 0 to 30 vol% within a photocurable resin. BTO, which has a relatively high dielectric constant (ε_r ~ 23) but a lower breakdown voltage (7 kV/mm), was used for the dielectric layer. In contrast, alumina, with a lower dielectric constant (ε_r ~ 6) but a higher breakdown voltage (43 kV/mm), was chosen for the body. Using the DLP (Digital Light Process) 3D printing technique, a body comprising alumina with an interdigitated electrode pattern was created. Subsequently, this body was coated with a dielectric layer composed of BTO. The structural dimensions of the ESC were optimized through finite element simulation (COMSOL) to achieve the maximum chucking force. The simulation result and the measured chucking force of the fabricated ESC were compared and analyzed. The ESC made of a combination of alumina (body) and BTO (dielectric layer) exhibited superior performance compared to ESCs made solely of alumina or BTO for both body and dielectric layer. Additionally, these findings were consistent with the simulation results. In this study, using FEA-optimized structures and selective material choices, we successfully fabricated an ESC through 3D printing methods.