VSB Reticle Enhancement for Precise Mask Pattern Transfer
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Solution Overview
Problem
Current reticle enhancement technologies face challenges in achieving precise and reliable pattern transfer on substrates, particularly at sub-wavelength scales, due to the complexity and computational intensity of adding sub-resolution assist features, which increases costs and labor, and struggles with manufacturing variations.
Innovation Solution
The method employs Mask Wafer Co-optimization (MWCO) that combines inverse lithography technology (ILT) for mask manufacturability and model-based Mask Data Preparation (MDP) for wafer quality, optimizing VSB shots to create an optimized mask pattern that enhances resolution without substantial increases in compute time or runtime, using techniques like curvilinear ILT and overlapping shots to reduce shot count and improve process window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sub-resolution assist features are added to enhance resolution, then manufacturing precision is improved, but device complexity and computational intensity increase
Solution Approach 1:
The patent performs reticle enhancement technology calculations and optimizations before actual mask fabrication. By pre-calculating the optimal mask patterns including sub-resolution assist features using computational models, the system determines the precise geometric modifications needed beforehand, reducing on-the-fly complexity during manufacturing while maintaining high precision pattern transfer.
Solution Approach 2:
The patent modifies mask pattern parameters such as feature dimensions, spacing, and geometric shapes to incorporate sub-resolution assist features. By systematically adjusting these parameters through computational optimization, the system enhances resolution and manufacturing precision while managing the complexity of the overall mask design through parameterized control.
2Manufacturing precision
If reticle enhancement technology is applied to improve pattern precision, then manufacturing precision is improved, but computational time and cost increase
Solution Approach 1:
The patent performs comprehensive reticle enhancement technology calculations and optimizations in advance, before mask fabrication and lithography processes. By pre-determining the optimal mask patterns through computational models that account for diffraction, interference, and other optical effects, the system reduces the need for iterative adjustments and minimizes computational time during actual manufacturing operations.
3Manufacturing precision
If multiple patterning processes are used to achieve finer geometries, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent incorporates reticle enhancement technology calculations during the initial mask design and fabrication stage, before the actual lithography manufacturing process. By pre-optimizing the mask patterns to account for optical effects and desired pattern outcomes, the system achieves high-resolution feature printing in fewer lithography steps, thereby maintaining productivity while improving manufacturing precision.
Data Source
AI summary
Methods for reticle enhancement technology (RET) for use with variable shaped beam (VSB) lithography include inputting a desired pattern to be formed on a substrate; determining an initial mask pattern from the desired pattern for the substrate; optimizing the initial mask pattern for wafer quality using a VSB exposure system; and outputting the optimized mask pattern. Methods for fracturing a pattern to be exposed on a surface using VSB lithography include inputting an initial pattern; overlaying the initial pattern with a two-dimensional grid, wherein an initial set of VSB shots are formed by the union of the initial pattern with locations on the grid; merging two or more adjacent shots in the initial set of VSB shots to create a larger shot in a modified set of VSB shots; and outputting the modified set of VSB shots.