Spatial Coherence Merging for Lithography Simulation Bottlenecks
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Solution Overview
Problem
The complexity of optical lithography simulation for semiconductor fabrication, particularly in optical proximity correction, is hindered by the high computational requirements associated with pixelated sources, which slow down the calculation of partially coherent imaging and create a bottleneck in constructing accurate OPC models.
Innovation Solution
The method involves treating neighboring source points as pseudo-spatially coherent area elements, reducing the number of incoherent points and simplifying calculations by using spatial coherence to perform efficient partially coherent imaging calculations, thereby speeding up Eigen-value decomposition and maintaining high resolution in source and pupil evaluations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixelated sources are used for optical lithography simulation, then high resolution in source and pupil evaluations is achieved, but computational complexity increases significantly
Solution Approach 1:
The patent merges neighboring spatially coherent source points into pseudo-coherent area elements. By treating multiple coherent points as a single computational unit, the number of incoherent points is reduced, thereby decreasing computational complexity while preserving the high resolution achieved through pixelated sources.
Solution Approach 2:
The patent segments the source points into spatially coherent groups based on their coherence properties. By dividing the source into regions of spatial coherence and treating each region as a pseudo-coherent element, the calculation burden is reduced without sacrificing the detailed resolution information.
2Reliability
If pixelated sources are used for optical lithography simulation, then accurate optical proximity correction models are achieved, but calculation speed decreases
Solution Approach 1:
The patent combines neighboring source points that exhibit spatial coherence into pseudo-coherent area elements. This merging reduces the total number of points requiring individual calculation, thereby increasing calculation speed while maintaining the accuracy needed for optical proximity correction models.
Solution Approach 2:
The patent changes the treatment parameter from treating each source point as completely incoherent to recognizing spatial coherence relationships. By adjusting the coherence assumption based on spatial proximity, the calculation efficiency is improved without compromising model accuracy.
3Ease of manufacture
If neighboring source points are treated as incoherent, then simplified calculation methods are used, but computational efficiency is reduced
Solution Approach 1:
The patent applies different coherence treatments to different spatial regions. Neighboring source points that are spatially coherent are treated as coherent, while distant points are treated as incoherent. This local differentiation simplifies calculations for coherent regions while maintaining computational efficiency.
Solution Approach 2:
The patent dynamically changes the coherence parameter based on the spatial relationship between source points. By adjusting the coherence assumption according to local spatial coherence properties, the calculation method adapts to achieve both simplicity and efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces computational complexity and enhances the efficiency of image calculations, allowing for faster and more accurate optical lithography simulations while maintaining high resolution, thus overcoming the bottlenecks in current pixelated source-based simulations.
Implementation Method 1
The spatial coherence property of neighboring source points is used to speed partially coherent imaging calculations
Data Source
AI summary
Computer-implemented techniques for pixel source optics calculations using spatial coherence are disclosed. Pixelated sources are used for source-mask co-optimization to enhance semiconductor lithography. Calculation of a partially coherent imaging system is used for optical-lithography simulation. The spatial coherence property of neighboring source points is used to reduce imaging calculation complexity. Two or more neighboring points are treated as one pseudo-spatially coherent area element.