Integrated Circuit Pattern Density Outlier Treatment
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Solution Overview
Problem
Current optical proximity correction methods in integrated circuit manufacturing have limited flexibility and uniformity in tuning pattern density, leading to issues like space charge effects and increased costs due to time-consuming simulations when using electron-beam lithography.
Innovation Solution
A method for fabricating integrated circuits that involves identifying pattern density outliers in the design layout, splitting them into subsets, and performing exposure processes with different doses to optimize pattern density uniformity, thereby reducing space charge effects and improving process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing OPC methods add dummy features to improve imaging resolution, then pattern density can be adjusted, but the degree of freedom and uniformity of pattern density tuning is limited
Solution Approach 1:
The patent segments the pattern density adjustment process into multiple stages: initial OPC with dummy features, followed by identification of density outliers, splitting outliers into subsets, and applying different exposure doses to different subsets. This segmentation enables fine-grained control over pattern density uniformity across the entire IC pattern.
Solution Approach 2:
The patent introduces dynamic exposure dosing where different subsets of patterns receive different exposure doses based on their local density characteristics. This dynamic approach allows the system to adaptively tune pattern density uniformity rather than using a fixed exposure dose for all patterns.
2Manufacturing precision
If existing OPC methods add dummy features to improve imaging resolution, then pattern density can be adjusted, but uniformity of pattern density is poor
Solution Approach 1:
The patent applies local quality by identifying density outliers in specific regions and applying targeted exposure dose adjustments to those regions. Different subsets of patterns receive different exposure doses tailored to their local density requirements, achieving uniform pattern density across the entire IC pattern rather than applying a uniform approach globally.
Solution Approach 2:
The patent implements a feedback mechanism where pattern density is calculated for the entire IC pattern, outliers are identified based on deviations from target density, and subsequent exposure dose assignments are adjusted based on this feedback to correct density non-uniformity in the next iteration.
3Manufacturing precision
If simulations and calculations for dummy features are performed to improve imaging resolution, then pattern density can be optimized, but process time and cost increase
Solution Approach 1:
The patent performs preliminary identification and categorization of density outliers before the main exposure process. By pre-calculating which regions are outliers and assigning them to different subsets, the system avoids time-consuming iterative simulations during production and enables faster manufacturing while maintaining optimization quality.
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 pattern density uniformity, reduces the space charge effect, and increases throughput by optimizing the exposure processes, addressing the limitations of existing OPC methods.
Implementation Method 1
when an electron-beam lithography technology is used to form the IC pattern
Implementation Method 2
This presents issues such as space charge effect and micro-loading effect when an electron-beam lithography technology is used
Data Source
AI summary
The present disclosure provides one embodiment of an IC method. First pattern densities (PDs) of a plurality of templates of an IC design layout are received. Then a high PD outlier template and a low PD outlier template from the plurality of templates are identified. The high PD outlier template is split into multiple subsets of template and each subset of template carries a portion of PD of the high PD outlier template. A PD uniformity (PDU) optimization is performed to the low PD outlier template and multiple individual exposure processes are applied by using respective subset of templates.