TWI827991B

The invention relates to a lower electrode assembly and a plasma processing device comprising the lower electrode assembly, and the lower electrode assembly comprises a pedestal; the electrostatic chuck is positioned on the base, is used for adsorbing a substrate to be treated and is made of a ceramic non-metal material; the gas conveying pipeline penetrates through the base and is used for conveying gas; the gas diffusion cavity, the gas inlet and the gas outlet are arranged in the electrostatic chuck, and gas from the gas conveying pipeline enters the gas diffusion cavity through the gas inlet, is diffused by the gas diffusion cavity and then is output to the back surface of a substrate to be processed through the gas outlet. The plasma processing apparatus can prevent arc discharge.