Abstract: An in-situ interferometer includes an image modifying optic that produces light ray bundles. The light ray bundles are projected onto a reticle with a plurality of measurement fiducials encoded onto a face of the reticle. The measurement fiducials are exposed onto a sensing plane and their locations measured. Aberrations in the projection system are determined from the measurements of the exposed reticles.

Abstract: An in-situ interferometer includes an image modifying optic that produces light ray bundles. The light ray bundles are projected onto a reticle with a plurality of measurement fiducials encoded onto a face of the reticle. The measurement fiducials are exposed onto a sensing plane and their locations measured. Aberrations in the projection system are determined from the measurements of the exposed reticles.

Abstract: A wafer stage overlay error map is created using standard overlay targets and a special numerical algorithm. A reticle including a 2-dimensional array of standard overlay targets is exposed several times onto a photoresist coated silicon wafer using a photolithographic exposure tool. After exposure, the overlay targets are measured for placement error using a conventional overlay metrology tool. The resulting overlay error data is then supplied to a software program that generates a 2-dimensional wafer stage distortion and yaw overlay error map.

Abstract: Techniques for determining wafer stage grid and yaw in a projection imaging tool are described. The techniques include exposing an overlay reticle onto a substrate having a recording media, thereby creating a plurality of printed fields on the substrate. The overlay reticle is then positioned such that when the reticle is exposed again completed alignment attributes are created in at least two sites in a first and a second printed field. The substrate is then rotated relative to the reticle by a desired amount. The overlay reticle is then positioned such that when the reticle is again exposed, completed alignment attributes are created in at least two sites in the first and a third printed field. Measurements of the complementary alignment attribute and a dynamic intra-field lens distortion are then used to reconstruct wafer stage grid and yaw error of the projection imaging system.

Abstract: A process for providing illumination source conditions for the accurate determination Zernike tilt coefficients in the presence of coma is described. Large feature-shift coma sensitivity is simulated for a range of illumination conditions. The resulting source sensitivity data is modeled and a practical array of source shapes, each of which is optimized to eliminate the effects of transverse distortion due to third-order coma, is identified. The optimized set of source shapes can be used to more accurately determine Zernike terms a2 and a3 using a variety of methods. Knowledge of the lens distortion data in the absence of coma induced shifts can be entered into more traditional overlay regression routines to better identify systematic and random error.

Abstract: A method and apparatus for determining lens distortion in a projection imaging tool are described. The techniques include exposing at least one alignment attribute onto a substrate having a recording media. A complementary alignment attribute is also exposed onto the substrate such that the complementary alignment attribute and alignment attribute form a completed alignment attribute. The exposure of the alignment attributes, or the complementary alignment attribute, or both, may be accomplished by multiple sub nominal dose exposures. Intra field distortion of the projection imaging tool is determined from measurements of the exposed completed alignment attributes. The alignment attributes and complimentary alignment attribute may be part of a reticle. The transmission of the alignment attribute may be different than the transmission of the complementary alignment attribute.

Abstract: An apparatus and method for manufacturing and using a calibrated registration reference wafer in a semiconductor manufacturing facility where an archive media includes etched alignment attributes. Exposing a pattern of complementary alignment attributes onto the archive media such that the pattern of complementary alignment attributes overlay and interlock with the etched alignment attributes thereby forming completed alignment attributes. Then, measuring offsets in the completed alignment attributes and constructing a calibration file for the archive media based upon the offset measurements and other characteristic data of the exposure tool.

Abstract: An apparatus and method for manufacturing and using a calibrated registration reference wafer in a semiconductor manufacturing facility. A reference reticle consisting of a 2-dimensional array of standard alignment attributes is exposed several times onto a photoresist coated semiconductor wafer using a photolithographic exposure tool. After the final steps of the lithographic development process the resist patterned wafer is physically etched using standard techniques to create a permanent record of the alignment attribute exposure pattern. The permanently recorded alignment attributes are measured for placement error using a conventional overlay metrology tool. The resulting overlay error data is used to generate a calibration file that contains the positions of the alignment attributes on the reference wafer. The reference wafer and calibration file can be used to determine the wafer stage registration performance for any photolithographic exposure tool.

Abstract: A reticle stage grid and yaw in a projection imaging tool is determined by exposing a first portion of a reticle pattern onto a substrate with a recording media thereby producing a first exposure. The first portion of the reticle pattern includes at least two arrays of alignment attribute that have features complementary to each other. The reticle stage is then shifted and a second portion of the reticle pattern is exposed. The first and second exposures overlap and interlock to create completed alignment attributes. Measurements of positional offsets of the completed alignment attributes are used to determine the reticle stage grid and yaw.

Abstract: A process for the determination of focal plane deviation uniquely due to the scanning dynamics associated with a photolithographic scanner is described. A series of lithographic exposures is performed on a resist coated silicon wafer using a photolithographic scanner. The lithographic exposures produce an array of focusing fiducials that are displaced relative to each other in a unique way. The resulting measurements are fed into a computer algorithm that calculates the dynamic scanning field curvature in an absolute sense in the presence of wafer height variation and other wafer/reticle stage irregularities. The dynamic scan field curvature can be used to improve lithographic modeling, overlay modeling, and advanced process control techniques related to scanner stage dynamics.

Abstract: A projection lens distortion error map is created using overlay targets and a special numerical algorithm. A reticle including an array of overlay targets is exposed several times onto a photoresist coated silicon wafer using a photolithographic stepper. After exposure, the overlay targets are measured for placement error. The resulting overlay error data is then supplied to a software program that generates a lens distortion error map for the photolithographic projection system.

Abstract: An in-situ apparatus for high resolution imaging in lithographic steppers and scanners (machines) is described. It comprises a multiple field in-situ imaging objective that images the source directly onto the machine reticle or objective plane. The image on the wafer side of the machine is then recorded electronically or in photo resist. Alternative embodiments create source images at locations before or beyond the wafer plane that can be more conveniently recorded with sensors embedded in the wafer stage chuck.

Abstract: Scanning synchronization error in a projection imaging system is controlled by obtaining one or more scanning synchronization error maps comprising a plurality of error components, obtaining one or more focal plane deviation (FPD) error maps comprising a plurality of error components, separating the one or more synchronization error maps and one or more FPD error map error components into one or more repeatable and non-repeatable parts, converting the repeatable parts into one or more mathematical models that express the repeatable parts in mode correctable and uncorrectable terms, inputting lens distortion map data, scanning synchronization error map data, FPD error map data, and the one or more mathematical models into a database linked to a process controller that executes process control algorithms, and correcting scanner motion of the projection imaging system based on output from the process controller.

Abstract: A reticle consisting of a 2-dimensional array of standard overlay targets is exposed several times onto a photoresist coated silicon wafer using a photolithographic scanner. Next, the overlay targets are measured for placement error using a conventional overlay metrology tool. The resulting overlay error data is then fed into a software program that generates the lens contribution to the intra-field error map for the photolithographic projection scanning system.

Abstract: An in-situ interferometer includes an image modifying optic that produces light ray bundles. The light ray bundles are projected onto a reticle with a plurality of measurement fiducials encoded onto a face of the reticle. The measurement fiducials are exposed onto a sensing plane and their locations measured. Aberrations in the projection system are determined from the measurements of the exposed reticles.

Abstract: A method and apparatus for determining the dynamic scanning distortion present in lithographic scanners. A special reticle pattern is exposed over the full field that is to be characterized. The wafer is then rotated 90 degrees and one or more exposures over the same field are made. Interlocking alignment structures on the resulting developed wafer are then measured and used to reconstruct the dynamic scanner distortion to within a translation, rotation, and scan skew. Alternative embodiments describe techniques for extracting the repeatable part of the dynamic scan error.

Abstract: A reticle consisting of a 2-dimensional array of standard overlay targets is exposed several times onto a photoresist coated silicon wafer using a photolithographic scanner. Next, the overlay targets are measured for placement error using a conventional overlay metrology tool. The resulting overlay error data is then fed into a software program that generates the lens contribution to the intra-field error map for the photolithographic projection scanning system.

Abstract: A photomask or reticle including a unique set of alignment attributes at separate and distinguishable field points is put in the reticle plane of a photolithographic projection system. The reticle pattern is exposed onto a resist coated wafer or substrate and processed through the final few steps of the photolithographic process. The resulting array of alignment attributes are then measured using a standard optical overlay metrology tool. The overlay tool is driven by a set of software instructions. By comparing the resulting overlay data to the placement error encoded on the reticle it can determined if the data has been read or displayed in the correct order.

Abstract: A photomask or reticle including a unique set of alignment attributes at separate and distinguishable field points is put in the reticle plane of a photolithographic projection system. The reticle pattern is exposed onto a resist coated wafer or substrate and processed through the final few steps of the photolithographic process. The resulting array of alignment attributes are then measured using a standard optical overlay metrology tool. The overlay tool is driven by a set of software instructions. By comparing the resulting overlay data to the placement error encoded on the reticle it can determined if the data has been read or displayed in the correct order.

Abstract: A process of measuring the radiant intensity profile of an effective source of a projection image system that has an effective source, an object plane, an imaging objective, an exit pupil, and an image plane. The improved process consists of selecting at least one field point and a corresponding aperture plane aperture and projecting a plurality of images of the selected field point through the corresponding selected aperture plane aperture at a plurality of various intensities of the effective source. By analyzing the recorded images of the effective source at various intensities it is possible to determine a radiant intensity profile of the image source at the selected field point.