Dielectric Coulomb mechanics model After the internal electrodes of the electrostatic chuck are applied with DC high voltage, the surface of the dielectric will generate polarized charges, which form an electrostatic field. The electrostatic field promotes the surface of the wafer placed on the electrostatic chuck (the contact surface with the electrostatic chuck). ) Polarized charges are generated. Charges with opposite polarities are gathered on the surface of the wafer and the surface of the electrostatic chuck (effective electrode). Charges of opposite sex are attracted to each other, and the wafer is closely adsorbed on the surface by the electrostatic chuck. Pay special attention to whether polarized charges or free charges are generated on the wafer surface depends on the conductivity of the wafer or coating. Semiconductor wafers such as silicon wafers generate free charges, and other insulator wafers such as sapphire generate polarized charges.

The dielectric layer of the electrostatic chuck is made of nano-ceramic powder and a suitable proportion of metal conductor powder. The electrical characteristics of the dielectric layer are between semiconductors and insulators. After the electrodes are applied with DC high voltage, the dielectric layer of the electrostatic chuck is mixed and sintered. The surface will generate a large amount of free charge under the action of the metal powder, and the free charge will move to the wafer (only for semiconductor wafers), and the free charge will increase the total amount of free charge on the semiconductor wafer. Under the action of the polarization electric field, the free charge on the surface of the semiconductor wafer and the corresponding area on the surface of the electrostatic chuck (effective electrode) gather charges of opposite polarity, and the charges of opposite sex are attracted to each other, and the semiconductor wafer is tightly adsorbed on its surface by the electrostatic chuck; In addition, for other insulator wafers such as sapphire, the total surface charge of the wafer remains unchanged, and the adsorption operation is completed by the action of polarization charges.