Variable-Length Conductive Line Ends for Semiconductor Overlay Margin
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing line end shortening of conductive features, which can lead to open circuits and decreased manufacturing yields, as feature sizes decrease, and existing solutions like complex lithography techniques have not adequately addressed this issue.
Innovation Solution
The method involves systematically extending the ends of conductive lines by varying amounts based on their proximity to adjacent lines, allowing for increased overlap with underlying contacts or vias without increasing the overall size of the integrated circuit, by selectively extending conductive line ends only where space is available in the layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the amount of overlap of conductive features to underlying vias or contacts is increased to solve line end shortening, then manufacturing precision is improved, but the overall size of the integrated circuit increases
Solution Approach 1:
The patent applies local quality by extending conductive line ends selectively only in regions where adjacent lines are sufficiently spaced apart. The extension is not applied uniformly across all conductive lines, but only where the local geometry permits without causing shorting. This localized approach increases overlay margin where needed while preserving the compact overall circuit layout.
Solution Approach 2:
The patent segments the conductive line layer into different regions based on the spacing to adjacent lines. Lines are categorized into those that should be extended and those that should not, creating distinct segments with different geometric properties. This segmentation allows differential treatment of conductive lines to optimize both overlay margin and circuit size.
2Manufacturing precision
If complex lithography techniques such as serifs are used to prevent line end shortening, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent changes the geometric parameter of conductive line ends by extending their length in specific regions. Instead of using complex lithography techniques like serifs, the solution modifies the simple linear dimension of the conductive lines themselves. This parameter change achieves line end shortening prevention through a straightforward geometric modification rather than complex patterning.
Data Source
AI summary
Semiconductor devices having conductive lines with extended ends and methods of extending conductive line ends by a variable distance are disclosed. An end of a first conductive feature of an interconnect structure is extended by a first distance, and an end of a second conductive feature of the interconnect structure is extended by a second distance, the second distance being different than the first distance. Ends of conductive features that are positioned close to adjacent conductive features are preferably not extended.