Abstract: A system for exposing a resist layer to an image that includes a layer reflective to imaging tool radiation and a resist layer having a region of photosensitivity over the reflective layer. An imaging tool projects radiation containing an aerial image onto the resist layer, with a portion of the radiation containing the aerial image passing through the resist and reflecting back to the resist to form an interference pattern of the projected aerial image through the resist layer thickness. The thickness and location of the resist layer region of photosensitivity are selected to include from within the interference pattern higher contrast portions of the interference pattern in the direction of the resist thickness, and to exclude lower contrast portions of the interference pattern in the resist thickness direction from said resist layer region of photosensitivity, to improve contrast of the aerial image in said resist layer region of photosensitivity.

Abstract: Disclosed is a method for illuminating a lithographic mask with light from different directions, in such a way that the intensities of the various incident beams provide the largest possible integrated process window. The process window is defined in terms of allowable ranges for printed shapes. For example, boundaries of the process window may be defined by shape limits corresponding to underexposed and overexposed conditions. Intensity parameters for representing the maximum possible intensities that can be permitted for overexposed tolerance positions are imposed through application of various constraints. Another set of intensity parameters for representing the minimum possible intensities that can be permitted for underexposed tolerance positions are imposed through application of various constraints. One parameter of each kind is defined for each of a number of different focal ranges. The optimum source intensities are determined from a linear program involving these and other constraints.

Abstract: A lithographic mask is illuminated with light from different directions such that intensities of a plurality of incident beams of light provide a largest possible integrated process window defined in terms of an allowed range for defining shapes. Constrained sets of intensity parameters are imposed. A first set of intensity parameters represents maximum possible intensities that can be permitted for overexposed tolerance positions. A second set of intensity parameters represents minimum possible intensities that can be permitted for underexposed tolerance positions. Optimum source intensities of incident beams are defined using a linear program and constraints. The optimum source intensities maximize an integrated range of dose and focal variations without causing printed shapes to depart from the allowed range. Apparatus are detailed and variations are described.

Abstract: Methods, and a program storage device for executing such methods, for performing model-based optical proximity correction by providing a mask matrix having a region of interest (ROI) and locating a plurality of points of interest within the mask matrix. A first polygon having a number of vertices representative of the located points of interest is computed, followed by determining a spatial relation between its vertices and the ROI. The vertices of the first polygon are then pinned to boundaries of and within the ROI such that a second polygon is formed on the ROI. The process is repeated for all vertices of the first polygon such that the second polygon is collapsed onto the ROI. This collapsed second polygon is then used to correct for optical proximity.

Abstract: Methods, and program storage devices, for performing model-based optical proximity correction by providing a region of interest (ROI) having an interaction distance and locating at least one polygon within the ROI. A cut line of sample points representative of a set of vertices, or plurality of cut lines, are generated within the ROI across at least one lateral edge of the polygon(s). An angular position, and first and second portions of the cut line residing on opposing sides of an intersection between the cut line and the lateral edge of the polygon are determined, followed by generating a new ROI by extending the original ROI beyond its interaction distance based on such angular position, and first and second portions of the cut line. In this manner, a variety of new ROIs may be generated, in a variety of different directions, to ultimately correct for optical proximity.

Abstract: Methods, and a program storage device for executing such methods, for performing model-based optical proximity correction by providing a mask matrix having a region of interest (ROI) and locating a plurality of points of interest within the mask matrix. A first polygon having a number of vertices representative of the located points of interest is computed, followed by determining a spatial relation between its vertices and the ROI. The vertices of the first polygon are then pinned to boundaries of and within the ROI such that a second polygon is formed on the ROI. The process is repeated for all vertices of the first polygon such that the second polygon is collapsed onto the ROI. This collapsed second polygon is then used to correct for optical proximity.

Abstract: A method for determining an image of a patterned object formed by a polychromatic lithographic projection system having a laser radiation source of a finite spectral bandwidth and a lens for imaging the patterned object to an image plane within a resist layer. The method comprises providing patterns for the object, a spectrum of the radiation source to be used in the lithographic projection system, an intensity and polarization distribution of the radiation source, and a lens impulse response in the spatial domain or in the spatial frequency domain of the image. The method then includes forming a polychromatic 4D bilinear vector kernel comprising a partially coherent polychromatic joint response between pairs of points in the spatial domain or in the spatial frequency domain, determining the dominant polychromatic 2D kernels of the polychromatic 4D bilinear vector kernel, and determining the image of the patterned object from convolutions of the object patterns with the dominant polychromatic 2D kernels.

Abstract: A method and system for exposing a resist layer with regions of photosensitivity to an image in a lithographic process using a high numerical aperture imaging tool. There is employed a substrate having thereover a layer reflective to the imaging tool radiation and a resist layer having a region of photosensitivity over the reflective layer, with the resist layer having a thickness. The imaging tool is adapted to project radiation containing an aerial image onto the resist layer, with a portion of the radiation containing the aerial image passing through the resist layer and reflecting back to the resist layer. The reflected radiation forms an interference pattern in the resist layer of the projected aerial image through the resist layer thickness.

Abstract: A method, program product and system is disclosed for performing optical proximity correction (OPC) wherein mask shapes are fragmented based on the effective image processing influence of neighboring shapes on the shape to be fragmented. Neighboring shapes are smoothed prior to determining their influence on the fragmentation of the shape of interest, where the amount of smoothing of a neighboring shape increases as the influence of the neighboring shape on the image process of the shape of interest decreases. A preferred embodiment includes the use of multiple regions of interactions (ROls) around the shape of interest, and assigning a smoothing parameter to a given ROI that increases as the influence of shapes in that ROI decreases with respect to the shape to be fragmented. The invention provides for accurate OPC that is also efficient.

Abstract: Disclosed is a method for illuminating a lithographic mask with light from different directions, in such a way that the intensities of the various incident beams provide the largest possible integrated process window. The process window is defined in terms of allowable ranges for printed shapes. For example, boundaries of the process window may be defined by shape limits corresponding to underexposed and overexposed conditions. Intensity parameters for representing the maximum possible intensities that can be permitted for overexposed tolerance positions are imposed through application of various constraints. Another set of intensity parameters for representing the minimum possible intensities that can be permitted for underexposed tolerance positions are imposed through application of various constraints. One parameter of each kind is defined for each of a number of different focal ranges. The optimum source intensities are determined from a linear program involving these and other constraints.

Abstract: Methods, and program storage devices, for performing model-based optical lithography corrections by partitioning a cell array layout, having a plurality of polygons thereon, into a plurality of cells covering the layout. This layout is representative of a desired design data hierarchy. A density map is then generated corresponding to interactions between the polygons and plurality of cells, and then the densities within each cell are convolved. An interaction map is formed using the convolved densities, followed by truncating the interaction map to form a map of truncated cells. Substantially identical groupings of the truncated cells are then segregated respectively into differing ones of a plurality of buckets, whereby each of these buckets comprise a single set of identical groupings of truncated cells. A hierarchal arrangement is generated using these buckets, and the desired design data hierarchy enforced using the hierarchal arrangement to ultimately correct for optical lithography.

Abstract: The present invention provides a lithographic method and apparatus (e.g., for printing contact holes on a wafer) that use a single mask, multiple exposures, and optimized pupil filtering. The method comprises: providing a mask including pattern features to be transferred to a wafer; transferring a first set of pattern features from the mask to the wafer using a first type of illumination and a first type of pupil filter; and transferring a second set of pattern features from the mask to the wafer using a second type of illumination and a second type of pupil filter.

Abstract: A method is described for performing model-based optical proximity corrections on a mask layout used in an optical lithography process having a plurality of mask shapes. Model-based optical proximity correction is performed by computing the image intensity on selected evaluation points on the mask layout. The image intensity to be computed includes optical flare and stray light effects due to the interactions between the shapes on the mask layout. The computation of the image intensity involves sub-dividing the mask layout into a plurality of regions, each region at an increasing distance from the evaluation point. The contributions of the optical flare and stray light effects due to mask shapes in each of the regions are then determined. Finally, all the contributions thus obtained are combined to obtain the final computation of the image intensity at the selected point.

Abstract: An efficient method and system is provided for computing lithographic images that takes into account vector effects such as lens birefringence, resist stack effects and tailored source polarizations, and may also include blur effects of the mask and the resist. These effects are included by forming a generalized bilinear kernel, which is independent of the mask transmission function, which can then be treated using a decomposition to allow rapid computation of an image that includes such non-scalar effects. Dominant eigenfunctions of the generalized bilinear kernel can be used to pre-compute convolutions with possible polygon sectors. A mask transmission function can then be decomposed into polygon sectors, and weighted pre-images may be formed from a coherent sum of the pre-computed convolutions for the appropriate mask polygon sectors. The image at a point may be formed from the incoherent sum of the weighted pre-images over all of the dominant eigenfunctions of the generalized bilinear kernel.

Abstract: A novel method and system for layout optimization relative to lithographic process windows which facilitates lithographic constraints to be non-localized in order to impart a capability of printing a given circuit with a process window beyond the process windows which are attainable with conventional simplified design rules.

Abstract: A method for optimizing the number of kernels N used in a sum of coherent sources (SOCS) for optical proximity correction in an optical microlithography process including setting the number of kernels N to a predetermined minimum value Nmin. A determination is made as to whether an accuracy estimate of calculated intensity is within a tolerable value. A determination is also made as to whether an added X/Y asymmetry estimate of the calculated intensity is negligible.

Abstract: Disclosed is a method for illuminating a lithographic mask with light from different directions, in such a way that the intensities of the various incident beams provide the largest possible integrated process window. The process window is defined in terms of allowable ranges for printed shapes. For example, boundaries of the process window may be defined by shape limits corresponding to underexposed and overexposed conditions. Intensity parameters for representing the maximum possible intensities that can be permitted for overexposed tolerance positions are imposed through application of various constraints. Another set of intensity parameters for representing the minimum possible intensities that can be permitted for underexposed tolerance positions are imposed through application of various constraints. One parameter of each kind is defined for each of a number of different focal ranges. The optimum source intensities are determined from a linear program involving these and other constraints.

Abstract: A method for calculating long-range image contributions from mask polygons. An algorithm is introduced having application to Optical Proximity Correction in optical lithography. A finite integral for each sector of a polygon replaces an infinite integral. Integrating over two triangles, rather than integrating on the full sector, achieves a finite integral. An analytical approach is presented for a power law kernel to reduce the numerical integration of a sector to an analytical expression evaluation. The mask polygon is divided into regions to calculate interaction effects, such as intermediate-range and long-range effects, by truncating the mask instead of truncating the kernel function.

Abstract: A first method to compute a phase map within an optical proximity correction simulation kernel utilizes simulated wavefront information from randomly generated data. A second method uses measured data from optical tools. A phase map is created by analytically embedding a randomly generated two-dimensional array of complex numbers of wavefront information, and performing an inverse Fourier Transform on the resultant array. A filtering function requires the amplitude of each element of the array to be multiplied by a Gaussian function. A power law is then applied to the array. The elements of the array are shuffled, and converted from the phasor form to real/imaginary form. A two-dimensional Fast Fourier Transform is applied. The array is then unshuffled, and converted back to phasor form.

Abstract: Methods, and program storage devices, for performing model-based optical lithography corrections by partitioning a cell array layout, having a plurality of polygons thereon, into a plurality of cells covering the layout. This layout is representative of a desired design data hierarchy. A density map is then generated corresponding to interactions between the polygons and plurality of cells, and then the densities within each cell are convolved. An interaction map is formed using the convolved densities, followed by truncating the interaction map to form a map of truncated cells. Substantially identical groupings of the truncated cells are then segregated respectively into differing ones of a plurality of buckets, whereby each of these buckets comprise a single set of identical groupings of truncated cells. A hierarchal arrangement is generated using these buckets, and the desired design data hierarchy enforced using the hierarchal arrangement to ultimately correct for optical lithography.