Abstract: A scanning exposure apparatus according to this invention has a light source which can change the central wavelength of exposure light to undergo pulsed oscillation, and scan-exposes a substrate with slit-like exposure light while periodically changing the central wavelength in synchronism with the pulsed oscillation of the exposure light. The scanning exposure apparatus includes a controller which controls the light source so that integrated values Sws and Swl obtained by integrating the intensity of the exposure light for each wavelength in the scanning direction in a short-wavelength range and long-wavelength range, respectively, assuming a target central wavelength as a reference satisfy: |(Sws?Swl)/(Sws+Swl)|?0.

Abstract: A method for predicting imaging characteristics fluctuation of a projection optical system in an exposure apparatus which projects a pattern formed on a mask onto a photosensitive substrate through the projection optical system is provided. In a measurement step, the projection optical system is irradiated with exposure light under a first exposure condition to measure first imaging characteristics fluctuation of the projection optical system. Then, before an imaging characteristics value is restored to an initial value at the start of irradiation after irradiation is stopped, the projection optical system is irradiated with the exposure light under a second exposure condition to measure second imaging characteristics fluctuation of the projection optical system. Approximate expressions of the measured first and second imaging characteristics fluctuations are calculated based on an imaging characteristics model.

Abstract: A laser unit for oscillating a laser of a first wavelength spectrum includes a wavelength selector for determining a first wavelength spectrum, and a drive mechanism for changing the first wavelength spectrum at a predetermined period.

Abstract: A speed control apparatus for a motor comprising a motor model formed of a motor current model and a motor speed model connected in cascade, a basic torque instruction signal being applied to the motor model, and first and second control loops comparing output signals from the motor current model and the motor speed model with an instantaneous actual motor current signal and an instantaneous actual motor speed signal respectively and generating first and second correction signal to be added to the basic torque instruction signal to form a corrected torque instruction signal which is applied to a motor current control circuit, whereby a speed oscillation is suppressed even when the motor is driving an oscillatory load.

Abstract: A vector control system for an induction motor driven by a power converter which generates three phase ac currents containing harmonics.