Metal Capacitor Segmented Lines for Leakage Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Metal capacitors in semiconductor devices face challenges with reduced charge storage and reliability due to decreased dimensions, leading to issues like leakage and shorts, while increasing spacing to avoid shorts decreases capacitance density and degrades electrical connection.
Innovation Solution
The formation of metal lines with alternating wide and narrow segments, where vias connect only the wide segments, maintains spacing and capacitance density, ensuring reliable electrical connection by increasing via density and spacing between different nets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vias are formed on all metal lines to improve electrical connection, then via density increases and conductivity improves, but spacing between vias and neighboring metal lines decreases causing leakage and shorts
Solution Approach 1:
The patent applies local quality by forming vias only on wide segments of metal lines while leaving narrow segments without vias. This localized approach ensures that vias are placed only where there is sufficient space, maintaining safe spacing from neighboring metal lines and preventing leakage and shorts, while still achieving adequate electrical connection through the wide segments.
Solution Approach 2:
The patent segments metal lines into wide and narrow portions, with vias formed only on wide segments. This segmentation allows the capacitor structure to have both regions with high via density (wide segments) for good electrical connection and regions with minimal via interference (narrow segments) for reliability, effectively resolving the contradiction between connection quality and leakage prevention.
2Reliability
If spacing between metal lines is increased to avoid shorts, then reliability improves, but total capacitor area increases and capacitance density decreases
Solution Approach 1:
The patent uses local quality by creating wide segments where vias are formed and narrow segments where they are not. This allows the capacitor to maintain high capacitance density through compact narrow segments while ensuring reliability through properly spaced vias on wide segments, avoiding the need to increase overall spacing between all metal lines.
3Area of stationary object
If narrow metal lines are used to maintain spacing and reduce area, then capacitance density is maintained, but via density decreases and electrical connection degrades
Solution Approach 1:
The patent segments metal lines into wide and narrow portions, with vias formed only on wide segments. This segmentation allows the capacitor structure to have both regions with high via density (wide segments) for good electrical connection and regions with minimal via interference (narrow segments) for reliability, effectively resolving the contradiction between connection quality and leakage prevention.
Solution Approach 2:
The patent applies local quality by forming vias only on wide segments of metal lines while leaving narrow segments without vias. This localized approach ensures that vias are placed only where there is sufficient space, maintaining safe spacing from neighboring metal lines and preventing leakage and shorts, while still achieving adequate electrical connection through the wide segments.
4Manufacturing precision
If via profile is controlled to be non-tapered for reliability, then manufacturing precision improves, but dual damascene process complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining which segments will be wide and which will be narrow before via formation. This preliminary segmentation allows subsequent via formation to proceed with simpler process control, as the locations requiring vias are already identified and sized appropriately, reducing the complexity of achieving precise via profiles.
Data Source
AI summary
A metal capacitor is formed with good conductivity for both nodes of the capacitor and improved reliability. An embodiment includes a first layer of alternating first and second metal lines, a second layer of alternating third and fourth metal lines, a dielectric layer between the first and second layers, and vias in the dielectric layer connecting the first and second metal lines with the third and fourth metal lines, respectively, wherein each metal line comprises alternating first segments having a first width and second segments having a second width, the first width being greater than the second width, each first segment lying adjacent to a second segment of an adjacent metal line, and only first segments of the metal lines overlapping the vias. The design enables the spacing between metal lines to be maintained, the spacing between via to metal to be increased, and via connection to be maintained for both nets, thereby improving the conductivity and reliability of the capacitor and maintaining capacitance density.