Electrostatic capacitance diaphragm vacuum gauge and vacuum processing apparatus
In an electrostatic capacitance diaphragm vacuum gauge, a diaphragm and a detection electrode opposing the diaphragm are arranged in a vacuum. The electrostatic capacitance diaphragm vacuum gauge measures pressure by measuring the change degree of an electrostatic capacitance between the diaphragm and detection electrode. The electrostatic capacitance diaphragm vacuum gauge includes atmospheric pressure variation factor detection units which detect atmospheric pressure variation factors as external factors that varies the pressure of the vacuum. The pressure of the vacuum is measured by subtracting information detected by the atmospheric pressure variation factor detection units.
1. An electrostatic capacitance diaphragm vacuum gauge which includes a diaphragm arranged to face an internal region of which a pressure is to be measured, and a detection electrode arranged to oppose said diaphragm, and which measures the pressure of the internal region by measuring a degree of change in an electrostatic capacitance between said diaphragm and said detection electrode, the gauge comprising:
a temperature measurement unit to measure a temperature of an external environment where the electrostatic capacitance diaphragm vacuum gauge is installed;
an atmospheric pressure measurement unit which measures an atmospheric pressure of the external environment where the electrostatic capacitance diaphragm vacuum gauge is installed;
an arithmetic unit which calculates an electrostatic capacitance corresponding to the external environment where the electrostatic capacitance diaphragm vacuum gauge is installed from information on at least one of a plurality of electrostatic capacitances measured in advance and stored in a memory unit on the basis of the environmental temperature and the environmental atmospheric pressure;
an electrostatic capacitance compensation unit which compares the measured electrostatic capacitance and the calculated electrostatic capacitance and compensates the measured electrostatic capacitance on the basis of the comparison result; and
an output characteristics compensation unit which compensates the characteristics on the basis of output characteristics on the environmental atmospheric pressure which is measured in advance and stored in the memory unit,
wherein said electrostatic capacitance compensation unit calculates a voltage based on the compensated electrostatic capacitance, and
said output characteristics compensation unit outputs the voltage calculated by said electrostatic capacitance compensation unit on the basis of the compensated output characteristics.
2. The electrostatic capacitance diaphragm vacuum gauge according to claim 1 , wherein said atmospheric pressure measurement unit includes a pressure sensor, and said temperature measurement unit includes a temperature sensor.
3. A vacuum processing apparatus which includes a vacuum vessel comprising an electrostatic capacitance vacuum gauge according to claim 1 .