| 摘要 |
PURPOSE:To obtain the electromagnetic deflection coil without generation of a time delay due to an eddy current by the detection output from a detection means for detecting an eddy current generated in a conductor arranged in the vicinity of an inductance according to the current flowing into the inductance. CONSTITUTION:In a primary-side coil L1 of a transformer T1, the current I1 which is similar to the current flowing in a deflection coil 24X flows to generate a magnetic flux and by a mutual inductance M, the current I2 which cancels the generated magnetic flux flows in a secondary-side coil L2. A time constant of the current I2 is determined by self-inductances L1 and L2 of the transformer and the values of resistors RM, R2 and etc. of the mutual inductance M and those values are selected properly. Especially, the effect of an eddy current is corrected by determining the time constant of the current value I2 according to the values of the resistors R2 and R3 and adjusting the values of the resistors R3-R5 so as to change a feedback quantity, and flowing a minute current DELTAI1 to the output of an amplifier 21. Namely, the influence of the eddy current upon the current I1 flowing the deflection coil 24X is cancelled and the position of an electron beam for a sample to be irradiated in an electron-beam exposing device can be controlled at a high speed without a delay. |
