INPUT ELECTRIC CURRENT MEASUREMENT SYSTEM Russian patent published in 2017 - IPC G01D5/24 

FIELD: metrology.

SUBSTANCE: invention relates to metrology, in particular, to current measurement methods. Measuring system contains current source and measuring circuit, which clamp is connected to current source. Current measurement circuit comprises power supply source connection clamp and voltage source, connected to power supply source terminals and made with possibility to supply disturbance voltage signal to power supply source. At that disturbance voltage is voltage, present at first input clamp, and has same value as measuring circuit input voltage. Voltage source generates signal with triangular or rectangular wave form. At that, voltage source is connected to capacitive sensor, and value of current strength generated by current source depends on distance between capacitive sensor and lithography device target. Current measurement circuit is built based on operational amplifier, and disturbance voltage is supplied to sources of supply through capacitors or inductors. Current measurement circuit also includes dividing and integrating circuits, amplifiers, current-voltage converters, differential circuits, selectors, filters, analogue-to-digital converter and digital processing circuit.

EFFECT: technical result is increased accuracy of measurements.

18 cl, 34 dwg