SENSOR HEAD FOR CRYSTAL-OSCILLATION-TYPE FILM THICKNESS MONITOR

摘要

Provided is a sensor head for a crystal-oscillation-type film thickness monitor that is capable of suppressing the stepping out of a stepper motor and the increase of motor excitation current. The sensor head comprises a sensor head body 1 having a motor Sm disposed therein, a holder 2 that has a plurality of crystal oscillation elements Co placed on the upper surface therof and is rotationally driven by the motor, and a mask body 3 that is attached to the sensor head body so as to cover the upper surface of the holder and has a film formation window 31 that is faced by one of the crystal oscillation elements. The part of the sensor head body positioned directly below the film formation window has a fixed first electrode 4 and second electrodes 5 that are electrically connected to each of the crystal oscillation elements and protrude from the bottom surface of the holder. When the holder rotates to a phase where one crystal oscillation element and the film formation window are vertically aligned, the first electrode and second electrode, which comprise the same metal, touch and are electrically connected. A lubricant supply means 4b for supplying solid lubricant to the surface of a second electrode before the same touches the first electrode is provided so as to be in front in the rotation direction of the holder.