Provided is a barrier seal for an electrostatic chuck in the plasma etching process. The barrier seal comprises multiple sealing portions to block the connecting layer of the electrostatic chuck and the plasma gas. The groove of the electrostatic chuck may be completely filled by the barrier seal. Even one of the multiple sealing portions is destroyed in the plasma etching process by the plasma gas, the barrier seal still prevents leaking of the electrostatic chuck effectively. The barrier seal provides a buffer period for engineers to replace the damaged barrier seal before the leaking occurs. Danger of leaking caused by abrupt breaking of the barrier seal is reduced. Furthermore, the barrier seal facilitates stability and safety of the plasma etching process. The yield of products manufactured by the electrostatic chuck may be improved.