Abstract: A projection exposure apparatus includes an illumination optical system for illuminating a pattern of a reticle with laser light from a continuous emission excimer laser, a projection optical system projecting the illuminated pattern onto a substrate, an adjusting device for adjusting an optical characteristic of the projection optical system in accordance with a change in wavelength of the laser, and a wavelength stabilizing device for stabilizing the wavelength of the laser light when the adjustment of the optical characteristic of the projection optical system by the adjusting device is insufficient.

Abstract: A projection exposure apparatus includes an illumination optical system for illuminating a pattern of a reticle with laser light from a continuous emission excimer laser, a projection optical system for projecting the illuminated pattern onto a substrate, wherein the projection optical system includes a lens system being made of a substantially single glass material, a wavelength detecting device for detecting a wavelength of the laser light from the excimer laser and for producing an output, and a displacing device for shifting a mirror for resonance of the excimer laser, in an optical axis direction of the excimer laser, on the basis of the output of the wavelength detecting device.

Abstract: Disclosed is a projection exposure apparatus which includes an illumination optical system for illuminating a pattern of a reticle with laser light from a continuous emission excimer laser, a projection optical system for projecting the illuminated pattern onto a substrate, and a wavelength stabilization mechanism for maintaining an emission wavelength of the excimer laser constant. The projection optical system is provided by a lens system being made of a substantially single glass material. With this arrangement, the pattern of the reticle can be projected on the substrate very accurately.

Abstract: Disclosed is a projection exposure apparatus which includes an illumination optical system for illuminating a pattern of a reticle with laser light from a continuous emission excimer laser, a projection optical system for projecting the illuminated pattern onto a substrate, and an adjusting unit for adjusting an optical characteristic of the projection optical system in accordance with a change in wavelength of the laser light. The projection optical system is provided by a lens system being made of a substantially single glass material. A wavelength monitor detects the emission wavelength of the excimer laser, on the basis of which the optical characteristic of the projection optical system is adjusted.

Abstract: Illuminance distribution measuring method and apparatus, in which the quantity of light on an area irradiated by a light beam emitted from a light source is detected by a combination of first and second detectors. The first detector is movable along the area to be irradiated and detects the quantity of irradiating light incident on the area to be irradiated while moving along the area irradiated. The second detector is fixedly secured at a predetermined position relative to the light source and the area to be irradiated and receives the light beam emitted from the light source to irradiate the area to be irradiated. On the basis of the outputs from the first and second detectors, the illuminance distribution on the area irradiated is accurately measured irrespective of any intensity changes of the light beam emitted from the light source.