Sensor head for crystal oscillator type of film thickness monitor

A sensor head for a crystal oscillator type of film thickness monitor, including:

• a sensor head main body with a stepping motor SM or a pneumatic rotary actuator being disposed therein;
• a holder having disposed therein a plurality of crystal oscillators in a same circumference at a distance from one another, the holder being adapted to be driven for rotation by the stepping motor SM or the pneumatic rotary actuator;
• provided that a direction from the sensor head main body toward the holder is defined as an upper side, a mask body mounted on the sensor head main body in a manner to cover an upper surface of the holder on which is disposed each of the crystal oscillators, the mask body also having opened therein a film-forming window to which faces any one of the crystal oscillators, the sensor head further comprising:
• a first electrode fixed to that portion of the sensor head main body which is positioned directly under the film-forming window;
• and
• a second electrode which is in electrical conduction with the respective crystal oscillators and which is disposed to protrude out of a lower surface of the holder such that, when the holder is rotated to a phase in which one crystal oscillator and the film-forming window coincide with each other in a vertical direction, the second electrode comes into contact with the first electrode so as to be in electrical conduction,
• wherein an insulating body is disposed on both sides, as seen in the direction of rotation of the holder, of one of the first electrode and the second electrode, the insulating body coming into sliding contact with the other of the first electrode and the second electrode, and
• wherein a flat part is formed at a top of the first electrode and defines an upper surface of the flat part,
• a hole is formed at the flat part,
• a contact member is formed in the hole, and
• an upper surface of the contact member is positioned so that a distance between the upper surface of the contact member and the lower surface of the holder is larger than a distance between the upper surface of the flat part and the lower surface of the holder.

A sensor head for a crystal oscillator type of film thickness monitor, including:

• a sensor head main body having disposed therein a stepping motor;
• a holder having disposed therein a plurality of crystal oscillators in a same circumference at a distance from one another, the holder being adapted to be driven for rotation by the stepping motor;
• provided that a direction from the sensor head main body toward the holder is defined as an upper side, a mask body mounted on the sensor head main body in a manner to cover an upper surface of the holder on which is disposed each of the crystal oscillators, the mask body also having opened therein a film-forming window facing any one of the crystal oscillators, the sensor head further comprising:
• a first electrode fixed to that portion of the sensor head main body which is positioned directly under the film-forming window;
• and second electrodes respectively in electrical conduction with each of the crystal oscillators, the second electrodes being disposed to protrude out of a lower surface of the holder such that, when the holder is rotated by the stepping motor to a phase in which any one of the crystal oscillators and the film-forming window coincide with each other in a vertical direction, the first electrode and the second electrodes, both being made of same kind of metal, come into contact with each other for electrical conduction,
• wherein
• the holder further has a ring plate part with a lower surface thereof,
• a plurality of radially elongated slit-shaped recessed parts is formed in the lower surface of the ring plate part, and
• a lower end of each of the second electrodes is made to protrude downward into the recessed part.