Abstract: A WDM demultiplexer/multiplexer comprising a plurality of narrow band reflective filters linearly disposed along an optical axis, each narrow band reflective filter reflecting a single channel or group of channels and transmitting the remaining channels, is described. In a demultiplexing mode, an optical signal initially carrying channels at &lgr;1&lgr;2 . . . &lgr;N travels along the optical axis. Each narrow band reflective filter reflects a distinct channel and is tilted with respect to the optical axis such that it directs the reflected beam away from the optical axis to an output. Each narrow band reflective filter is substantially transparent to the remaining channels of the optical signal, such that the remainder of the optical signal proceeds along the optical axis substantially undisturbed.

Abstract: An optical interleaver for receiving an incident beam carrying a wavelength-division-multiplexed (WDM) signal comprising a plurality of channels at center wavelengths &lgr;1, &lgr;2, &lgr;3, &lgr;4, &lgr;5, &lgr;6, . . . and generating therefrom at least one de-interleaved output signal comprising the odd channels &lgr;1, &lgr;3, &lgr;5, . . . or the even channels &lgr;2, &lgr;4, &lgr;6, . . . is described. The optical interleaver comprises a splitting element for splitting an incident beam into a first optical signal directed along a first path and a second optical signal directed along a second path, a first resonant element positioned along the first path, a second resonant element positioned along the second path, and a combining element positioned to receive and to interferometrically combine the outputs of the first and second resonant to produce the output signal.

Abstract: A simple −1X, catadioptric projection relay system (e.g., a modified Wynne-Dyson relay) is combined with a linear scanning and object and image indexing systems to provide good imagery over a useful field which is two or more times wider than the field size of the projection system and arbitrarily long. The projection system has opposed and parallel object and image planes and produces an image in which object and image vectors in one direction are parallel and in a normal direction are opposed. The reticle and substrate are clamped and scanned together in the parallel direction and are indexed in the normal direction by equal and opposite amounts between scans. An example shows how a 2.5 micron resolution, i-line projection system with a 300 mm wide field could be used to expose a 550 mm wide substrate In two scans to yield a very high throughput.

Abstract: The invention is directed to a four-mirror catoptric projection system for extreme ultraviolet (EUV) lithography to transfer a pattern from a reflective reticle to a wafer substrate. In order along the light path followed by light from the reticle to the wafer substrate, the system includes a dominantly hyperbolic convex mirror, a dominantly elliptical concave mirror, spherical convex mirror, and spherical concave mirror. The reticle and wafer substrate are positioned along the system's optical axis on opposite sides of the mirrors. The hyperbolic and elliptical mirrors are positioned on the same side of the system's optical axis as the reticle, and are relatively large in diameter as they are positioned on the high magnification side of the system. The hyperbolic and elliptical mirrors are relatively far off the optical axis and hence they have significant aspherical components in their curvatures.

Abstract: The apparatus of this invention redirects light input to the apparatus without significant light loss, and preferably without increasing the light's etendue. The apparatus includes a light guide and a redirection member. The member has input, output and reflective surfaces. The member's input surface is joined to the light guide to define an interface, and the member's output surface is situated adjacent to a medium that can be another light guide or redirection member, a gas such as ambient air, or a vacuum, for example. The member is configured to redirect light traveling in the light guide from its reflective surface by a predetermined redirection angle.

Abstract: This invention includes a pin mirror arranged to receive light, preferably from a laser source. The pin mirror has a reflective surface that diffracts and reflects the received light to generate a diffraction-limited spherical wavefront. The pin mirror can reflect the wavefront in a predetermined direction by angling the pin mirror's reflective surface with respect to the direction of travel of the light incident to the pin mirror. The capability of the pin mirror to generate a diffraction-limited spherical wavefront and to direct the wavefront in a predetermined direction provides the capability to test objects or systems with relatively high numerical apertures, and yet allows for a reduction in the number and criticality of the properties of optical elements that would otherwise be required in an interferometer.

Abstract: A substrate alignment and exposure system is disclosed The alignment is performed by capturing an image of the substrate with a pattern recognition system, determining the offset from the alignment and moving the substrate relative to the reticle to be in alignment. A first optical alignment system which captures an image of a position of the substrate off of the primary axis of the exposure optics is used to perform pre-alignment. A second optical alignment system captures an image of the reticle and the substrate through the lens of the exposure optics. The pattern recognition system recognizes the alignment keys on the reticle, alignment targets on the substrate, and computes their positions and displacement from alignment. The relative alignment can be direct or inferred. Any angular and translational misalignment is calculated. The pattern recognition system then moves the substrate to be in alignment with the reticle.

Abstract: An optical system to project an image from an illuminated object to an image plane with a selected magnification factor. This system includes a lens system having a fixed magnification factor and at least one flat plate that is optically compatible with the lens system and which when bent into a cylindrical shape varies the fixed magnification factor of the lens system along one axis of the image. This variable magnification technique is applicable to all lens system types, including a Wynne Dyson type projection system. In addition, a Wynne Dyson optical projection system that includes an optical block in place of the usual fold prism is discussed. The optical block reduces changes in distortion caused by heat transferred from the reticle. The block permits the inclusion of a dichroic beamsplitter diagonally through the optical block which presents minimal attenuation of the exposure illumination.

Abstract: An alignment system for a unit magnification system (such as a Half-Field Dyson system) for use in microlithography is provided. The alignment system provides for aligning a pattern on a reticle with a complementary pattern on a wafer.

Abstract: Disclosed is tilt-sensing means that employs a point source of alternate 1st or 2nd divergent light beams which, after passing through collimating lenses of the Half-Field Dyson projection optics of the stepper, are separately incident on and reflected from a reflective pattern disposed on the surface of a reticle and from a reflective surface of a wafer, together with two-dimensional position detection means responsive to the position of each of the reflected alternate 1st or 2nd divergent light beams, for independently sensing the angular position of the surface of the reticle and the angular position of the surface of the wafer to determine thereby whether or not the surface of the reticle and the surface of the wafer are substantially parallel to one another.

Abstract: An illumination system for use in a unit magnification optical projection system (such as a Half-Field Dyson system) is provided. In a Half-Field Dyson system, a reticle and a wafer are parallel to each other with a window being provided on the reticle to allow for projection of the reticle pattern onto the wafer. The present invention provides uniform bright illumination over the reticle pattern with little or no spill over through the reticle window.

Abstract: A microlithographic stepper, employing a Half-Field Dyson projection optical system, achieves focusing of an image of a first-layer reticle pattern on a completely unpatterned reflective wafer surface by including a repetitive diffraction pattern on the reticle which has a configuration in which a particular ordinal diffraction order is normally missing. In response to being simultaneously illuminated with each of two incident monochromatic beams of light, diffraction orders generated by the repetitive diffraction pattern are imaged on the reflective wafer surface and then reflected back to and reimaged on the repetitive diffraction pattern on the reticle. Diffraction orders generated on the first encounter with the repetitive diffraction pattern generate light in the originally missing ordinal diffraction order on the second encounter.