Optimization of source, mask and projection optics
First Claim
1. A method for configuring a lithographic process, the method comprising:
- obtaining a cost function of design variables that affect characteristics of the lithographic process, the design variables comprising a design variable of projection optics used in the lithographic process, wherein the cost function characterizes a result of the lithographic process, the result including an effect of the design variable of the projection optics; and
configuring, by a hardware computer, one or more of the characteristics of the lithographic process by adjusting at least some of the design variables including the design variable of the projection optics, until a termination condition for the cost function is satisfied.
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Abstract
Embodiments of the present invention provide methods for optimizing a lithographic projection apparatus including optimizing projection optics therein, and preferably including optimizing a source, a mask, and the projection optics. The projection optics is sometimes broadly referred to as “lens”, and therefore the joint optimization process may be termed source mask lens optimization (SMLO). SMLO is desirable over existing source mask optimization process (SMO), partially because including the projection optics in the optimization can lead to a larger process window by introducing a plurality of adjustable characteristics of the projection optics. The projection optics can be used to shape wavefront in the lithographic projection apparatus, enabling aberration control of the overall imaging process. According to the embodiments herein, the optimization can be accelerated by iteratively using linear fitting algorithm or using Taylor series expansion using partial derivatives of transmission cross coefficients (TCCs).
62 Citations
25 Claims
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1. A method for configuring a lithographic process, the method comprising:
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obtaining a cost function of design variables that affect characteristics of the lithographic process, the design variables comprising a design variable of projection optics used in the lithographic process, wherein the cost function characterizes a result of the lithographic process, the result including an effect of the design variable of the projection optics; and configuring, by a hardware computer, one or more of the characteristics of the lithographic process by adjusting at least some of the design variables including the design variable of the projection optics, until a termination condition for the cost function is satisfied. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification