Abstract: A mask alignment system for integrated circuit lithography achieves reticle to wafer referencing. A detection system located below the main projection lens detects the image of reticle alignment marks while also detecting wafer alignment marks. The reticle marks are imaged in light at the exposure wavelength. A first detection method images the fluorescence produced in the photoresist by the reticle mark images. A microscope located below the main projection lens produces the image and also images the wafer marks with broadband non-actinic illumination. The second method images the reticle marks in exposure light using a microscope which images and detects the exposure wavelength while maintaining the illumination and detection of the wafer marks. The third method collects directly both the exposure light and fluorescent light that is scattered and reflected from the wafer surface; the presence of wafer alignment marks changes this light collection.

Abstract: A method and apparatus for determining performance characteristics in lithographic tools includes projecting a predetermined image with a projection system having a known predetermined performance characteristic to obtain data indicative of the relationship between the size of the projected image and the predetermined performance characteristic. The same image is then projected in a system having an unknown value for the predetermined performance characteristic. The predetermined performance characteristic for the system under consideration is then determined based on the data obtained when the image was projected in the system having the known predetermined performance characteristic.

Abstract: Improvements in a focusing apparatus having an objective optical system for optically manufacturing a workpiece, forming a desired pattern on a surface of a workpiece or inspecting a pattern on a workpiece and used to adjust the state of focusing between the surface of the workpiece and the objective optical system. The focusing apparatus has a first detection system having a detection area at a first position located outside the field of the objective optical system, a second detection system having a detection area at a second position located outside the field of the objective optical system and spaced apart from the first position, and a third detection system having a detection area at a third position located outside the field of the objective optical system and spaced apart from each of the first and second positions.

Abstract: A dual guide beam stage mechanism for accurate X-Y positioning for use e.g. in semiconductor processing equipment provides accurate planar motion and yaw control. Over-constraint between components in their relative motion is minimized by utilizing flexibly mounted air bearings at the connection between at least one of the moveable guide beams and its corresponding stationary guide, and between at least one of the guide beams and the adjacent stage itself. Thus stage yaw motion is provided by allowing yaw motion of one of the guide beams. Preloading provides enough constraint through the air bearings without over-constraining the moving components, thereby improving accuracy and also reducing the need for close manufacturing tolerances.

Abstract: A film measurement apparatus having a stage with a support surface on which a substrate coated with a film may rest. An extended light source faces the stage, and an imager is aimed at the stage to capture the reflection of the light source. The imager includes a receiver upon which an image of at least an extended portion of the substrate may be generated, and a processor in communication with the imager is operable to calculate the thickness of the film at plurality of locations. The stage may be tilted to empirically measure an average illumination and the contrast between interference fringes, avoiding theoretical estimates provided by Fresnel'equation.

Abstract: A method of detecting particles on a wafer support surface comprising positioning a wafer in a first position on the surface with the wafer in the first position, generating a first pattern on the wafer, and moving the wafer. Then, after moving the wafer, generating a second pattern on the wafer to generate a moire pattern by the interaction of the second pattern with the first pattern. The moire pattern is inspected to identify any visual distortion in the moire pattern due to physical distortion of the wafer caused by a particle on the support surface during the generation of the first pattern. The patterns may be ruled parallel lines, and the second pattern may be moved during inspection to shift the moire pattern to reveal distortions over a wide area.

Abstract: A method of providing a beam having precisely orthogonally polarized components includes generating a beam with substantially orthogonally polarized components, splitting the beam to separate the components to separate paths, projecting each component into a respective polarization preserving optical fiber (PPF) or polarizing fiber, recombining the components output from the fibers into a single beam, and transmitting the single beam to an interferometer. The PPFs are rotationally adjustable at their output ends to provide precise orthogonality in the resulting beam.

Abstract: A method and apparatus to analyze the aerial image of an optical system using a subwavelength slit. A slit configuration yields a higher signal-to-noise ratio than that achievable with a round aperture. The slit also allows the polarization of the aerial image to be analyzed. In an alternative embodiment a tunneling slit is used. The tunneling slit comprises an optically transparent ridge-like structure mounted to a substrate, the combined structure covered by a thin, planar metal film.

Abstract: An XY stage for precision movement for use in aligning a wafer in a microlithography system. A main stage supporting the wafer straddles a movable beam that is magnetically driven in a first linear direction in the XY plane. A follower stage, mechanically independent of the main stage, also moves in the first linear (X) direction and its motion is electronically synchronized by a control system with the main stage motion in the X direction. Electromagnetic drive motors include magnetic tracks mounted on the follower stage which cooperate with motor coils mounted on the edges of the main stage to move the main stage in a second linear (Y) direction normal to the X direction. Thus the main stage is isolated from mechanical disturbances in the XY plane since there is no mechanical connections and is lightened by removing the weight of the magnetic tracks from the beam.

Abstract: A mechanical scanner design suitable for use in a step and scan lithography system with arbitrary image magnification includes a projection optical system (20) and a relatively rotatable platform (40). The optical system has the property that a point within a predetermined object field in a first plane is imaged with suitable magnification at a corresponding point within a corresponding image field in a second plane, parallel to the first plane. The object and image fields are displaced from each other. A light source (22) illuminates an aperture such as a slit which is imaged in the object plane, whereupon a slit image is formed in the image plane. The reticle and wafer are mounted to the platform at respective locations in the object and image planes.

Abstract: An interferometer used to measure distance to an object is provided with a laser sheath. The sheath encloses a substantial part of the measurement beam's path to provide a controlled environment which reduces environmental influences on the measured distance. The sheath is of variable length and responsive to a follower so as to maintain a sheath end nearest the object at a small distance from the object. An environmental controller controls the environment within the sheath. The environment within the sheath can be a vacuum or a suitable gas or gas mixture. A corrector can be used to compensate the interferometer's measured-distance signal for detected environmental characteristics to produce a corrected signal which indicates distance between the interferometer and the reflective surface. The apparatus and methods can be used to measure and control stage position in a projection-type wafer exposure system which is affected by variations in its atmospheric environment.

Abstract: A guideless stage for aligning a wafer in a microlithography system is disclosed, and a reaction frame is disclosed which isolates both external vibrations as well as vibrations caused by reaction forces from an object stage. In the guideless stage an object stage is disclosed for movement in at least two directions and two separate and independently movable followers move and follow the object stage and cooperating linear force actuators are mounted on the object stage and the followers for positioning the object stage in the first and second directions. The reaction frame is mounted on a base structure independent of the base for the object stage so that the object stage is supported in space independent of the reaction frame. At least one follower is disclosed having a pair of arms which are respectively movable in a pair of parallel planes with the center of gravity of the object stage therebetween.

Abstract: A reduction projection system (10) characterized by large numerical aperture has an unobscured optical path without the need to resort to truncated lens elements. The system includes first and second reduction stages. The first reduction stage includes a first mirror group (20) and a first lens group (30). The second reduction stage includes a second mirror group (40) and a second lens group (50). Together, the first mirror group and the first lens group form an intermediate reduced image of the object at an intermediate image region (70). The second mirror group and the second lens group form a further reduced image at an image plane (15).

Abstract: A light source having a solid state laser emitting a beam that is separated into a number of segments. Each segment is frequency shifted by a different amount so that the segments do not substantially overlap in the frequency domain. Each segment passes through a short focal length lens element of a fly's eye array to be dispersed onto a mask plane for evenly illuminating a mask. The lens elements of the fly's eye array are contained within a small region in comparison to the width of the dispersed beam segments, such that each beam segment contributes illumination to the entirety of a common portion of the mask.

Abstract: An improved method for stitching together reticle patterns on a substrate is described. One or more reticles, whose reticle border patterns are to be blended together on the substrate, are provided on an X-Y movable stage in a scanning type exposure system. Each of the reticles has a border pattern which is identical to the border pattern of at least one of the other reticles so that, when the images of these reticles border patterns overlap on the substrate, the overlapping border patterns effectively form a single image on the substrate. To prevent the double exposure of the overlapping border patterns from overexposing the photoresist and to reduce any detrimental effects resulting from misalignment between the overlapping patterns, either a triangular end portion of the scanning source, a filter, or a movable blind is used to partially shade the overlapping border pattern as the UV source is scanned over the border pattern.

Abstract: A reduction projection system characterized by large numerical aperture has an unobscured optical path without the need to resort to truncated lens elements and provides locations for field and aperture stops. The system includes a first lens group, a first double-pass component group, a first concave mirror, a second lens group, a second double-pass component group, a second concave mirror, and a third lens group. The light encounters the first double-pass component group before and after it encounters the first concave mirror. Similarly, the light encounters the second double-pass component group before and after it encounters the second concave mirror. Together, the first lens group, the first double-pass component group, the first concave mirror, and the second lens group form an intermediate reduced image of the object at an intermediate image plane. The second double-pass component group, the second concave mirror, and the third lens group form a further reduced image at an image plane.

Abstract: An integrated optical device for magneto-optical recording and/or reading employs elements that may be fabricated on a substrate using semiconductor manufacturing technology. Such elements include, but are not limited to, a system of waveguides for transmitting light energy beams from lasers to end portions of the waveguides exposed to the outside of the substrate, and from those end portions to detectors, so that reading, writing, focusing, and tracking operations may be performed. The waveguide systems include, e.g., polarization controllers and mode splitters.