摘要:
A simplified version of a multiexpose mask optimization problem is solved in order to find a compressed space in which to search for the solution to the full problem formulation. The simplification is to reduce the full problem to an unconstrained formulation. The full problem of minimizing dark region intensity while maintaining intensity above threshold at each bright point can be converted to the unconstrained problem of minimizing average dark region intensity per unit of average intensity in the bright regions. The extrema solutions to the simplified problem can be obtained for each source. This set of extrema solutions is then assessed to determine which features are predominantly printed by which source. A minimal set of extrema solutions serves as a space of reduced dimensionality within which to maximize the primary objective under constraints. The space typically has reduced dimensionality through selection of highest quality extrema solutions.
摘要:
A simplified version of a multiexpose mask optimization problem is solved in order to find a compressed space in which to search for the solution to the full problem formulation. The simplification is to reduce the full problem to an unconstrained formulation. The full problem of minimizing dark region intensity while maintaining intensity above threshold at each bright point can be converted to the unconstrained problem of minimizing average dark region intensity per unit of average intensity in the bright regions. The extrema solutions to the simplified problem can be obtained for each source. This set of extrema solutions is then assessed to determine which features are predominantly printed by which source. A minimal set of extrema solutions serves as a space of reduced dimensionality within which to maximize the primary objective under constraints. The space typically has reduced dimensionality through selection of highest quality extrema solutions.
摘要:
Programmable illuminators in exposure tools are employed to increase the degree of freedom in tool matching. A tool matching methodology is provided that utilizes the fine adjustment of the individual source pixel intensity based on a linear programming (LP) problem subjected to user-specific constraints to minimize the difference of the lithographic wafer data between two tools. The lithographic data can be critical dimension differences from multiple targets and multiple process conditions. This LP problem can be modified to include a binary variable for matching sources using multi-scan exposure. The method can be applied to scenarios that the reference tool is a physical tool or a virtual ideal tool. In addition, this method can match different lithography systems, each including a tool and a mask.
摘要:
A method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material including: defining a representation of the mask; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; imposing a set of metric constraints based on one of the first and second relationships; setting up an objective function of optimization based on the remaining of the two relationships; determining optimum constrained values of the representation of the mask based on the set of metric constraints and the objective function; and outputting these values.
摘要:
A method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material including: defining a representation of the mask; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; imposing a set of metric constraints based on one of the first and second relationships; setting up an objective function of optimization based on the remaining of the two relationships; determining optimum constrained values of the representation of the mask based on the set of metric constraints and the objective function; and outputting these values.
摘要:
Programmable illuminators in exposure tools are employed to increase the degree of freedom in tool matching. A tool matching methodology is provided that utilizes the fine adjustment of the individual source pixel intensity based on a linear programming (LP) problem subjected to user-specific constraints to minimize the difference of the lithographic wafer data between two tools. The lithographic data can be critical dimension differences from multiple targets and multiple process conditions. This LP problem can be modified to include a binary variable for matching sources using multi-scan exposure. The method can be applied to scenarios that the reference tool is a physical tool or a virtual ideal tool. In addition, this method can match different lithography systems, each including a tool and a mask.
摘要:
A method, system, computer program product and table lookup system for calculating image intensity for a mask used in integrated circuit processing are disclosed. A method may comprise: decomposing a Manhattan polygon of the mask into decomposed areas based on parallel edges of the Manhattan polygon along only one dimension; determining a convolution of each decomposed area based on a table lookup; determining a sum of coherent systems contribution of the Manhattan polygon based on the convolutions of the decomposed areas; and outputting the determined sum of coherent system contribution for analyzing the mask.
摘要:
A method, system, computer program product and table lookup system for calculating image intensity for a mask used in integrated circuit processing are disclosed. A method may comprise: decomposing a Manhattan polygon of the mask into decomposed areas based on parallel edges of the Manhattan polygon along only one dimension; determining a convolution of each decomposed area based on a table lookup; determining a sum of coherent systems contribution of the Manhattan polygon based on the convolutions of the decomposed areas; and outputting the determined sum of coherent system contribution for analyzing the mask.
摘要:
Techniques are presented that include accessing results of forward simulations of circuit yield, the results including at least circuit yield results including simulated device shapes. Using the circuit yield results, high-level traits of at least the simulated device shapes are determined. Based on the determined high-level traits and using the circuit yield results, a compact model for predicted yield is constructed, the compact model including a plurality of adjustable parameters, and the constructing the compact model for predicted yield including adjusting the adjustable parameters until at least one first predetermined criterion is met. An optimization problem is constructed including at least the compact model for yield, an objective, and a plurality of constraints. Using the optimization problem, the objective is modified subject to the plurality of constraints until at least one second predetermined criterion is met.
摘要:
A method for illuminating a mask to project a desired image pattern into a photoactive material is described. The method includes receiving an image pattern. Determining a relationship between source pixels in a set of source pixels to desired intensities at one or more points in the image pattern is performed. Linear constraints are imposed on a set of intensity values based on one or more contingent intensity condition. The contingent intensity conditions include integer variables specifying contingent constraints. The method includes determining values of the set of intensity values in accordance with the linear constraints, using a constrained optimization algorithm. The set of intensity values represents intensities of a set of source pixels. The set of intensity values are output. Apparatus and computer readable storage media are also described.