摘要:
A wafer stage (24) comprises a flat lower heater (38), upper and lower ceramic-metal members (40A, 40B) cooperating to sandwich the lower heater (38), and an electrostatic ceramic chuck (28) arranged on the upper side of the ceramic-metal member (40A) for holding a wafer (W) to be processed. The ceramic-metal member (40A) and the electrostatic chuck (28) have substantially the same coefficient of linear expansion so that the difference in deformation between the two will not cause separation or damage to the electrostatic chuck (28).