Fill Shapes for Double-Patterning Density Balancing
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Solution Overview
Problem
The double-patterning technique in semiconductor manufacturing leads to uneven material density on integrated circuit wafers due to chemical mechanical polishing, causing 'dishing' issues where the periphery surface becomes higher than the array surface, potentially reducing manufacturing margins and thinning metal in the array below reliable limits.
Innovation Solution
A computer-implemented method generates fill shapes along tracks associated with net shapes, decomposable into two colors, to equalize material density across the IC die, using blocking regions to construct fill shapes on alternating tracks while maintaining double patterning design rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double-patterning technique is used to increase pattern density, then manufacturing precision is improved, but material density uniformity deteriorates causing dishing
Solution Approach 1:
The patent applies local quality by adding fill shapes specifically in periphery regions that have lower material density, while maintaining the original design in array regions. This creates non-uniform fill distribution that compensates for local density variations, ensuring uniform CMP removal rates across different regions of the IC die.
Solution Approach 2:
The patent changes the density parameter by introducing additional fill shapes in periphery regions. This modifies the material distribution parameter to achieve more uniform density across the wafer surface, directly addressing the dishing problem caused by non-uniform CMP removal.
2Stability of the object's composition
If fill shapes are added to periphery regions, then material density uniformity is improved, but device complexity increases
Solution Approach 1:
The patent segments the IC die into array regions and periphery regions, applying different fill strategies to each. Fill shapes are added only in periphery regions, while array regions maintain their original design integrity. This segmentation approach reduces the overall complexity impact by limiting fill insertion to specific areas.
Solution Approach 2:
The patent introduces fill shapes as intermediary elements that mediate between the original design and the CMP process requirements. These fill shapes act as compensatory features that balance material density without interfering with the functional design elements.
3Stability of the object's composition
If fill shapes are placed near DPT shapes, then material density uniformity is improved, but manufacturing precision deteriorates due to spacing rule violations
Solution Approach 1:
The patent performs preliminary placement of fill shapes in periphery regions before final DPT mask generation. By pre-positioning fill shapes and establishing blocking regions, the method ensures that subsequent DPT shape placement maintains proper spacing relationships, preventing spacing rule violations.
Solution Approach 2:
The patent extracts or removes blocking regions after fill shape placement to prevent interference with DPT shapes. This extraction ensures that fill shapes do not violate spacing rules with DPT shapes while maintaining their density-balancing function in periphery regions.
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 effectively reduces dishing problems during CMP by balancing material density, ensuring the periphery and array regions have consistent surface levels, thereby maintaining reliable current handling and signal integrity.
Implementation Method 1
Advanced process technologies use chemical mechanical polishing (CMP) techniques to flatten or 'planarize' the surface of a semiconductor wafer
Data Source
AI summary
A computer-implemented method for constructing a design characterized by a double patterning layer is presented. The method includes receiving the design in a memory of the computer when the computer is invoked to construct the design. The method further includes generating, using the computer, a multitude of fill shapes along a multitude of tracks associated with a multitude of net shapes. The multitude of fill shapes and the multitude of net shapes are decomposable into two colors in accordance with a spacing constraint of the double patterning layer.