WAFER STAGE ASSEMBLY

A wafer stage assembly is provided to separate a thermocouple and a ground wire such that the thermocouple is installed at a portion of the wafer stage, in which an insulating layer is not formed, in a non-contact method. A wafer stage assembly includes gas injection parts(10,12), a wafer stage(20), a ceramic arm(24), a heating part(30), a thermocouple(40), a ground wire(42), and a fixing part(50). The gas injection parts(10,12) inject gas onto a surface of a wafer(22). The wafer(22) is placed on the wafer stage(20). The ceramic arm(24) supports the wafer stage. The heating part(30) is disposed under a process chamber to heat the wafer. The thermocouple(40) detects a temperature of the wafer. The ground wire(42) grounds a radio frequency accumulated on the wafer stage. The fixing part(50) fixes the thermocouple to the ground wire.