Double Patterning Monitoring Pattern for Stitching Defect Detection
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Solution Overview
Problem
In integrated circuit fabrication, double patterning technologies face issues with pattern stitches, leading to layout pattern distortion, reliability concerns, and printability reductions due to light diffraction and stitching defects such as displacement and short-circuiting, especially at nanometer scales.
Innovation Solution
A monitoring pattern with a combination of line-ended and non-line-ended cuts, including corner and T-shaped cuts, is used on a semiconductor wafer to check for pattern cut displacement and adjust stitching dimensions, ensuring accurate overlay and enhancing reliability and printability by comparing stitching critical dimensions between the monitoring and target patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double pattern lithography technology is used to reduce layout pattern pitches, then finer pitches can be obtained, but stitches are introduced that degrade reliability and printability
Solution Approach 1:
The patent introduces a monitoring pattern that is segmented into multiple measurement regions, each containing specific geometric features (line-ended cuts, non-line-ended cuts, corners, T-junctions) that independently monitor different aspects of stitching accuracy. This segmentation allows comprehensive monitoring of stitching defects across various pattern types without requiring a single complex measurement structure.
Solution Approach 2:
The monitoring pattern serves as an intermediary structure between the actual circuit patterns and the stitching process. By placing these dedicated monitoring structures at stitching locations, the system can indirectly measure and control stitching accuracy without interfering with the primary circuit fabrication. The monitoring pattern acts as a mediator that translates stitching quality into measurable geometric parameters.
2Manufacturing precision
If double pattern lithography technology is used to reduce layout pattern pitches, then finer pitches can be obtained, but pattern defects such as stitching displacement or short-circuiting occur
Solution Approach 1:
The monitoring pattern is designed and placed in advance at anticipated stitching locations before the actual double patterning process occurs. These pre-positioned structures with known geometric characteristics allow the system to predict potential stitching defect locations and types, enabling preventive measurement and adjustment before defects propagate to the actual circuit patterns.
Solution Approach 2:
The monitoring pattern provides feedback mechanisms by containing measurable geometric features whose dimensions and positions directly reflect stitching quality. By measuring features such as the distance between line-ended cuts, corner positions, or T-junction geometries in the monitoring pattern, the system receives quantitative feedback about stitching displacement, which can then be used to adjust subsequent stitching operations or identify patterns requiring rework.
3Reliability
If monitoring pattern with multiple cut types is used to check pattern cut displacement, then reliability and printability increase, but device complexity increases
Solution Approach 1:
The monitoring pattern is designed as a multi-functional structure that simultaneously performs multiple monitoring tasks. The same monitoring pattern contains line-ended cuts for monitoring linear feature stitching, non-line-ended cuts for monitoring continuous feature alignment, corners for monitoring orthogonal stitching, and T-junctions for monitoring junction accuracy. This universal design allows a single monitoring pattern to comprehensively assess all types of stitching defects without requiring separate monitoring structures for each defect type.
Data Source
AI summary
A monitoring pattern for pattern stitch in double patterning is provided with a plurality of pattern cuts that include at least one line-ended cut and at least one non-line-ended cut, wherein every pattern cut has a stitching critical dimension (CD). A semiconductor wafer having at least one target pattern corresponding to the monitoring pattern is also provided. A method for monitoring pattern stitch can be preformed to check for pattern cut displacement in stitching areas and to increase reliability and printability of layouts, by comparing corresponding stitching critical dimensions of the target pattern and the monitoring pattern.