Diamond-Shaped Landing Pads for Semiconductor Contact Reliability
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Solution Overview
Problem
Highly integrated semiconductor devices face reliability issues due to bridging or necking problems in contact plugs, which can lead to decreased performance and reliability.
Innovation Solution
The semiconductor device incorporates diamond-shaped landing pads with asymmetrical diagonals, where each landing pad is electrically connected to an underlying active area and overlaps bit line structures and contact holes, with a portion filling the contact hole to prevent unoccupied spaces, ensuring reliable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact plugs are used to connect upper and lower elements in highly integrated semiconductor devices, then electrical connections are established, but bridging or necking occurs leading to deterioration in reliability
Solution Approach 1:
The patent applies asymmetry by designing the landing pad with a diamond shape where the first diagonal has a different length than the second diagonal. This asymmetric geometry prevents symmetric bridging between adjacent contact plugs while maintaining proper electrical connections, thereby resolving the reliability issue caused by conventional symmetric contact plug designs.
Solution Approach 2:
The patent implements local quality by creating a diamond-shaped landing pad with unequal diagonals that locally modifies the contact region geometry. This localized asymmetric structure prevents bridging at specific critical locations between contact plugs without affecting the overall device architecture, addressing the necking and bridging problems in highly integrated devices.
2Productivity
If high degree of integration is achieved in semiconductor devices, then design rules for elements are decreased, but bridging and necking in contact plugs occur
Solution Approach 1:
The asymmetric diamond shape with unequal diagonals provides built-in geometric control that maintains manufacturing precision even as device integration increases. The unequal diagonal lengths create inherent spacing control that prevents bridging between closely spaced contact plugs, enabling high integration without sacrificing contact plug formation precision.
3Reliability
If diamond-shaped landing pads with asymmetrical diagonals are used, then bridging and necking are prevented, but device complexity increases
Solution Approach 1:
The patent resolves the complexity issue by implementing a diamond shape with asymmetrical diagonals, which maintains geometric simplicity while effectively preventing bridging and necking. The asymmetric diamond can be fabricated using standard photolithography and etching processes, avoiding the need for complex multi-step patterning while achieving reliable contact plug formation in highly integrated devices.
Data Source
AI summary
A semiconductor device can include a plurality of landing pads arranged according to a layout on a substrate, wherein a cross-sectional shape of each of the landing pads has a diamond shape so that opposing interior angles of the diamond shape are equal to one another and adjacent interior angles of the diamond shape are unequal to one another.