ELECTRICAL STATIC CHUCK HAVING SHADOW RING

摘要

PURPOSE: An electrical static chuck is provided to minimize a deposition of particles between a wafer and a guide ring by forming a shadow ring between the wafer and the guide ring. CONSTITUTION: The electrostatic chuck(38) comprises a chuck(40) having a wafer loading surface and a guide ring(42) for surrounding the wafer loading surface. The electrostatic chuck(38) further includes a shadow ring(44) for coating interfaces between a wafer(W) and the guide ring(42). The shadow ring(44) further comprises a horizontal part(44a) parallel to the upper surface of the guide ring(42) and a vertical part(44b) contact with edge portions of the wafer(W). The shadow ring(44) is made of a silicon(Si), a SiC or a ceramic materials.