Defocusing effects by undesired wafer tilt caused by photoresist debris in prior art photolithographic apparatus are substantially eliminated by a novel plate for supporting a wafer to be imaged without generating debris. Three tabs are provided along the periphery of an aperture in the plate. Each tab is provided with a spherical body, such as a ball, precisely positioned in a predetermined plane, and arranged to contact the wafer at a tangent to the surface of the spherical body. Relative movement while loading the wafer in the apparatus with respect to the supporting balls causes substantially no discernible debris from the wafer surface material. Imaging defects on the wafer due to photoresist debris are also substantially eliminated by the apparatus.

A slit light emitting type hot cathode fluorescent tube illumination system including at least one substrate, a plurality of strip anodes, a plurality of fluorescent substance layers each superposed on one of the anodes, and hot cathode filaments located above top surfaces of the fluorescent substance layers for emitting thermoelectrons exciting the fluorescent substance layers to emit light for illuminating an original by slit illumination. A cylindrical lens is located in a path of the light emitted by the fluorescent substance layers in such a manner that the generating line of the cylindrical lens is parallel to the length of the fluorescent substance layers. The substrate and cylindrical lens cooperate with each other to provide an illumination system in tubular form, with the aid of a side plate when necessary.

A condenser lens system is provided for forming an effective circular source of NUV-DUV radiation which is the telecentric stop of the system and is characterized by a short focal length and higher marginal irradiance to compensate for marginal cosine losses. The system utilizes a long arc medium/low pressure mercury lamp which is surrounded by a large paraboloidal reflector and is mounted below the focal point of the reflector to generate a converging radiation beam directed to the condenser lens system. The system then projects the effective circular source of NUV-DUV radiation to a lens system comprising two plano convex lenses to convert the effective circular source into a collimated beam for out-of-contact printing of large substrates. The highly collimated and spatially coherent beam can be used to irradiate a telecentric objective for projection exposure on wafer steppers or flood exposure systems.

A movable light-source type exposure apparatus comprising a light source disposed at the focal point of a parabolic reflector, a first light-shielding member disposed right beneath the light source and intended to prevent the light rays from the light source from being irradiated directly over a mask and a work, a second light-shielding member disposed closely to the mask and work so as to cause the formation of a shadow capable of equalizing the cumulated amounts of light rays at points thereon, a positioning/fixing means intended, for each exposure, to position and fix a retaining frame for the mask and a retaining frame for the work, and a light-source moving means for moving a lamp house having the parabolic reflector, light source, first light-shielding member and second shielding member over the mask and work for purpose of causing the same to be exposed.

A compact, full-frame flash illumination system is disclosed. In a unity mode of operation, a lens, mounted within a light housing, projects an image of a document onto a photoreceptor belt. In a reduction mode of operation, the lens is translated towards the photoreceptor along a non-linear path which maintains document registration at the image plane. Simultaneously, the platen is translated upward by a mechanical drive arrangement to maintain conjugate requirements.