Patent ID: 8092638

Claim:
A plasma reactor for processing a workpiece, comprising: a reactor chamber; an electrostatic chuck within said chamber comprising an upper insulating puck layer having a top surface for supporting a workpiece and a lower conductive base layer, and an axial cylindrical probe hole extending through said base layer and into said puck layer, and a temperature probe in said electrostatic chuck, said temperature probe comprising: (I) an upper probe in said upper insulating puck layer and comprising: (A) an opaque insulative cylindrical upper probe sleeve and a cap at a top of said upper probe sleeve, said upper probe sleeve extending axially into said probe hole, a top end of said upper probe sleeve being located at a top end of said probe hole beneath said top surface; (B) an optically responsive temperature transducer within said upper probe sleeve at said top end of said upper probe sleeve; (C) an upper optical fiber having a top end coupled to said optically responsive temperature transducer and extending axially through said upper probe sleeve; (II) a lower probe below said lower conductive base layer and comprising: (A) an elongate cylindrical lower probe sleeve having a top end facing and contacting a bottom end of said upper probe; (B) a lower optical fiber having a top end facing a bottom end of said upper optical fiber and extending axially through said lower probe sleeve; (III) an upper coil spring biasing said upper probe sleeve toward said top end of said probe hole; and (IV) a lower coil spring biasing said lower probe sleeve toward the bottom end of said upper probe, said upper coil spring having greater stiffness than said lower coil spring, wherein said upper probe further comprises a receptacle opening coaxial with said upper optical fiber and shaped to receive a top end of said lower probe sleeve.