Optical Proximity Correction Bias Grouping for Mask Fabrication
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Solution Overview
Problem
In photolithography processes, the close proximity of image patterns on masks leads to interference and diffraction issues, resulting in distortions during the printing of layouts on semiconductor wafers, which can cause unintended circuit patterns and operational failures in electronic devices.
Innovation Solution
A method is introduced to divide the design layout into segments, calculate overlapping areas with comparison areas, classify segments into groups based on these areas, assign representative bias values to each group, and update the layout to minimize errors between the actual and target layouts, thereby fabricating a mask with more precise image patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical proximity correction is performed by calculating individual bias values for all segments, then manufacturing precision is improved, but device complexity and calculation time increase
Solution Approach 1:
The patent divides the layout into multiple segments and further groups these segments based on their geometric characteristics and proximity relationships. This hierarchical segmentation allows the correction process to handle complex layouts by breaking them down into manageable groups that can be processed with common bias values, reducing overall computational complexity while maintaining precision where needed
Solution Approach 2:
The patent applies different bias values to different groups of segments based on their local characteristics. By identifying segments with similar geometric and proximity properties and assigning them common bias values, the method achieves local optimization without requiring unique correction parameters for every individual segment, thus balancing precision with process simplicity
2Manufacturing precision
If the number of segments is increased for detailed correction, then manufacturing precision is improved, but calculation time and processing duration increase
Solution Approach 1:
The patent implements a two-level segmentation approach where the layout is first divided into multiple fine segments for detailed analysis, then these segments are grouped into coarser categories based on shared characteristics. This allows the system to maintain high precision through fine-grained initial segmentation while reducing calculation time by processing grouped segments with common parameters
Solution Approach 2:
The patent applies full detailed correction only to segments that require it based on their proximity and geometric characteristics, while applying simplified common bias values to segments where high precision is less critical. This selective approach reduces overall calculation time while maintaining necessary precision in critical areas
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 enhances the efficiency and uniformity of optical proximity correction, leading to the fabrication of masks with improved precision and reduced errors, ensuring that the printed circuit patterns align with the intended design, thus preventing operational failures in electronic devices.
Implementation Method 1
The transparent area passes light and the opaque area does not pass light. The transparent area and the opaque area form image patterns that are used to print the layout on the wafer when light emitted from a light source is projected to the wafer via the image patterns of the mask.
Implementation Method 2
Due to this close proximity, interference and diffraction of light may occur, and thus, a layout that is different from a desired layout may be printed on a wafer.
Implementation Method 3
Due to this close proximity, interference and diffraction of light may occur, and thus, a layout that is different from a desired layout may be printed on a wafer.
Data Source
AI summary
A mask fabricating method includes dividing an outline of a design layout into segments, setting comparison areas with respect to an evaluation point corresponding to each of the segments, for each segment, calculating an overlapping area between the design layout and each of the comparison areas, classifying the segments into groups based on the calculated overlapping areas, wherein segments having a characteristic of the same overlapping area are included in a first group, calculating bias values for each of the segments, obtaining a representative bias value for each group, for each group, assigning the representative bias value obtained for that group to each of its segments, updating the design layout based on the segments with their assigned representative bias values, and fabricating a mask based on the updated design layout.