Semiconductor ESD Layouts for Reduced On-Die Capacitance
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Solution Overview
Problem
Reducing parasitic capacitance in semiconductor devices is challenging due to increased size reduction, which leads to higher fringing capacitance from conductive structures carrying different voltages, affecting device speed and performance.
Innovation Solution
The metallization structure is rearranged by grouping metal traces into parallel and interleaved groups, increasing the separation between traces carrying dissimilar voltages, thereby reducing parasitic on-die capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conductive structures are positioned nearer to one another to reduce device size, then device footprint is reduced, but parasitic capacitance increases
Solution Approach 1:
The conductive structures are segmented into multiple groups with different voltage potentials. By dividing the continuous conductive structures into discrete segments and organizing them into separate groups, the patent reduces the harmful capacitive coupling between adjacent conductors carrying different voltages, thereby reducing parasitic capacitance while maintaining compact device footprint.
Solution Approach 2:
The patent groups conductive structures carrying the same voltage potential together and positions them adjacent to one another. This equipotential arrangement eliminates voltage differences between neighboring conductors, thereby eliminating parasitic capacitance between them. Conductors at different potentials are separated by larger spacing, further reducing capacitive coupling.
2Ease of manufacture
If device size is reduced through scaling, then manufacturing cost is reduced, but parasitic capacitance increases affecting device speed
Solution Approach 1:
The patent segments conductive structures into multiple groups organized by voltage potential. This segmentation allows compact scaling of the device while maintaining controlled spacing between different voltage groups, preventing parasitic capacitance from increasing proportionally with scaling, thereby preserving device speed performance.
Solution Approach 2:
The patent applies different spacing rules to different regions of the device based on local voltage requirements. Areas with conductors at the same potential have minimal spacing, while areas with different potentials have increased spacing. This localized optimization allows aggressive scaling in some regions while maintaining low parasitic capacitance in critical high-speed signal paths.
3Area of stationary object
If conductive structures carrying different voltages are positioned nearer to one another, then device area is reduced, but fringing capacitance increases
Solution Approach 1:
The patent positions conductive structures carrying the same voltage potential adjacent to one another, creating equipotential regions. This eliminates voltage differences between neighboring conductors, thereby eliminating fringing electric fields and associated fringing capacitance. Different voltage groups are separated by sufficient spacing to minimize capacitive coupling.
Solution Approach 2:
The patent merges multiple conductive structures carrying the same voltage potential into closely spaced groups or bundles. By combining these equipotential conductors, the patent reduces the overall device area while the unified potential minimizes internal capacitive effects. Different voltage groups are then positioned at optimized distances from one another.
Data Source
AI summary
Semiconductor devices having busing layouts configured to reduce on-die capacitance are disclosed herein. In one embodiment, a semiconductor device includes an electrostatic discharge device electrically connected in parallel with an integrated circuit and configured to divert high voltages generated during an electrostatic discharge event away from the integrated circuit. The semiconductor device further includes a signal bus and a power bus electrically connected to the electrostatic discharge device. The signal bus includes a plurality of first fingers grouped into first groups and the power bus includes a plurality of second fingers grouped into second groups. The first groups are positioned generally parallel to and interleaved between the second groups.