ASELTA Nanographics

Port-Saint-Louis-du-Rhône, France

ASELTA Nanographics

Port-Saint-Louis-du-Rhône, France
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The invention discloses a method to easily determine the parameters of a second process for manufacturing from the parameters of a first process. Metrics representative of the differences between the two processes are computed from a number of values of the parameters, which can be measured for the two processes on a calibration layout, or which can be determined from pre-existing values for layouts or reference data for the two processes by an interpolation/extrapolation procedure. The number of metrics is selected so that their combination gives a precise representation of the differences between the two processes in all areas of a design. Advantageously, the metrics are calculated as a product of convolution of the target design and a compound of a kernel function and a deformation function.


A method for transferring a pattern onto a substrate by direct writing by means of a particle or photon beam, the method comprising:- a step of producing a dose map, associating a dose to each of a plurality of elementary features of said pattern; and- a step of exposing the substrate according to the pattern with a spatially-dependent dose depending on said dose map;characterized in that said step of producing a dose map includes:- computing at least two metrics for each of said elementary features of the pattern; and- determining the emitted dose associated to each of said elementary features of the pattern as a function of said metrics. A computer program product for carrying out such a method or at least said step of producing a dose map.


A method to easily determine the parameters of a second process for manufacturing from the parameters of a first process is provided. Metrics representative of the differences between the two processes are computed from a number of values of the parameters, which can be measured for the two processes on a calibration layout, or which can be determined from pre-existing values for layouts or reference data for the two processes by an interpolation/extrapolation procedure. The number of metrics is selected so that their combination gives a precise representation of the differences between the two processes in all areas of a design. Advantageously, the metrics are calculated as a product of convolution of the target design and a compound of a kernel function and a deformation function.


An IC manufacturing model is disclosed, wherein input variables and an output variable are measured using a calibration set of patterns. The model can or cannot include a PSF. The output variable may be a dimensional bias between printed patterns and target patterns or simulated patterns. It can also be a Threshold To Meet Experiments. The input variables may be defined by a metric which uses kernel functions, preferably with a deformation function which includes a shift angle and a convolution procedure. A functional or associative relationship between the input variables and the output variable is defined. Preferably this definition includes normalization steps and interpolation steps. Advantageously, the interpolation step is of the kriging type. The invention achieves a much more accurate modeling of IC manufacturing, simulation or inspection processes.


Patent
French Atomic Energy Commission and Aselta Nanographics | Date: 2015-06-02

A method for calculating the parameters of a resist model of an IC manufacturing process is provided. Accordingly, a function representative of the target design convoluted throughout the whole target design with a kernel function compounded with a deformation function with a shift angle. The deformation function is replaced by its Fourier series development, the order of which is selected so that the product of convolution is invariant through rotations within a tolerance of the corrections to be applied to the target design. Alternatively, the product of convolution may be decomposed into basic kernel functions selected varying by angles determined so that a deformation function for a value of the shift angle can be projected onto a couple of basic kernel functions the angles of which are proximate to the shift angle.


A method for transferring a fractured pattern decomposed into elementary shapes, onto a substrate by direct writing by a particle or photon beam, comprises a step of identifying at least one elementary shape of the fractured pattern, called removable elementary shape, whose removal induces modifications of the transferred pattern within a preset tolerance envelope; a step of removing the removable shape or shapes from the fractured pattern to obtain a modified fractured pattern; and an exposure step, comprising exposing the substrate to a plurality of shots of a shaped particle or photon beam, each shot corresponding to an elementary shape of the modified fractured pattern. A computer program product for carrying out such a method is provided.


A method for transferring a fractured pattern (210, 310), decomposed into elementary shapes, onto a substrate by direct writing by means of a particle or photon beam, comprisinga step of identifying at least one elementary shape (2000) of the fractured pattern, called removable elementary shape, whose removal induces modifications of the transferred pattern within a preset tolerance envelope;- a step of removing said removable shape or shapes from the fractured pattern, to obtain a modified fractured pattern (220, 230) ; and- an exposure step, comprising exposing the substrate to a plurality of shots of a shaped particle or photon beam, each shot corresponding to an elementary shape of said modified fractured pattern. A computer program product for carrying out such a method.


The invention discloses a method to easily determine the parameters of a second process for manufacturing from the parameters of a first process. Metrics representative of the differences between the two processes are computed from a number of values of the parameters, which can be measured for the two processes on a calibration layout, or which can be determined from pre-existing values for layouts or reference data for the two processes by an interpolation/extrapolation procedure. The number of metrics is selected so that their combination gives a precise representation of the differences between the two processes in all areas of a design. Advantageously, the metrics are calculated as a product of convolution of the target design and a compound of a kernel function and a deformation function. A reference physical model of the reference process is determined. A sizing correction to be applied to the edges of the design produced by the reference process is calculated. It is then converted, totally or partially, into a dose correction.


According to the invention, an IC manufacturing model is disclosed, wherein input variables and an output variable are measured using a calibration set of patterns. The model can or not include a PSF. The output variable may be a dimensional bias between printed patterns and target patterns or simulated patterns. It can also be a Threshold To Meet Experiments (TTME). The input variables may be defined by a metric which uses kernel functions, preferably with a deformation function which includes a shift angle and a convolution procedure. A functional or associative relationship between the input variables and the output variable is defined. Preferably this definition includes normalization steps and interpolation steps. Advantageously, the interpolation step is of the kriging type. The invention achieves a much more accurate modeling of IC manufacturing, simulation or inspection processes.


Patent
Aselta Nanographics | Date: 2016-06-29

The invention discloses an improved method of geometry corrections to be applied to properly transfer semiconductor designs on a wafer or a mask in nanometer scale processes. In contrast with some prior art techniques, geometry corrections and possibly dose corrections are applied before fracturing. Unlike edge based corrections, where the edges are displaced in parallel, the displacements applied to generated geometry corrections according to the invention do not preserve parallelism of the edges, which is specifically well suited for free form designs. A seed design is generated from the target design. Vertices connecting segments are placed along the seed design contour. Correction sites are placed on the segments. Displacement vectors are applied to the vertices. A simulated contour is generated and compared to the contour of the target design. The process is iterated until a match criteria between simulated and target design (or another stop criteria) is reached.

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