EUV Mask Image Accuracy via Coupling Filter Angle Thresholds
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Solution Overview
Problem
Current EUV mask manufacturing methods face challenges in accurately reflecting the mask topography effect and coupling effect between edges, leading to errors in pattern formation on semiconductor wafers due to limitations in edge filter applications.
Innovation Solution
The method involves generating a first EUV mask image using thin mask approximation, determining edge pair angles, applying coupling or edge filters based on angle tolerance, and combining images to create a final EUV mask image, with an optical proximity correction model to improve pattern accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional EUV mask manufacturing methods are used, then the manufacturing process is simple, but the accuracy of the EUV mask image is insufficient due to inability to reflect mask topography effect and coupling effect between edges
Solution Approach 1:
The patent segments the EUV mask manufacturing process into multiple distinct steps: generating initial mask image data, calculating edge pair angles, determining coupling effects based on angle thresholds, applying coupling filters, and generating final mask image data. This segmentation allows each step to be optimized independently while maintaining overall process manageability.
Solution Approach 2:
The patent performs preliminary calculations of edge pair angles and determines coupling effects before generating the final mask image data. By pre-calculating these parameters and identifying which edge pairs require coupling filters, the method prepares the necessary information in advance, enabling more accurate final image generation without excessive complexity during the main manufacturing process.
2Manufacturing precision
If edge filters are applied to all edges, then the mask topography effect is addressed, but the computational efficiency decreases and errors in pattern formation increase due to inadequate handling of coupling effects
Solution Approach 1:
The patent applies coupling filters selectively to specific edge pairs based on their calculated angles, rather than uniformly to all edges. By identifying edge pairs with angles below a threshold that exhibit significant coupling effects, the method applies filtering only where necessary, optimizing both accuracy and computational efficiency.
Solution Approach 2:
The patent uses angle threshold parameters to determine when coupling effects should be applied. By changing the parameter from applying filters to all edges to applying filters only when the edge pair angle is below a specific threshold, the method optimizes the balance between pattern formation accuracy and computational time.
Data Source
AI summary
Provided is an extreme ultraviolet (EUV) mask manufacturing method of forming an optimum pattern on a wafer by efficiently reflecting a mask topography effect or a coupling effect between edges of a pattern and improving the accuracy of an EUV mask image. The EUV mask manufacturing method includes performing an optical proximity correction (OPC) method for obtaining EUV mask design data, transferring the EUV mask design data as mask tape-out (MTO) design data, preparing mask data based on the MTO design data, and completing an EUV mask by exposing an EUV mask substrate based on the mask data, wherein the performing of the OPC method applies a coupling filter to both a first case in which angles of an edge pair satisfy |θ1−θ2|=0, and a second case in which angles of an edge pair satisfy 0<|θ1−θ2|≤an angle tolerance.