Lateral Capacitive Isolation Structure for Compact High-Voltage ICs
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Solution Overview
Problem
The semiconductor industry faces challenges in providing sufficient galvanic isolation for high voltage applications in integrated circuit (IC) chips with smaller dimensions and increased density, as conventional capacitive isolation methods require excessive vertical stack height of dielectric material layers for effective isolation.
Innovation Solution
The semiconductor structure incorporates a substrate with a first isolation structure, an isolation layer, and a second electrode, where the isolation layer is positioned laterally between the electrodes, preventing electrical current transmission while allowing capacitive coupling for signal transmission, thereby enabling galvanic isolation without the need for multiple vertically stacked dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capacitive isolation methods using vertically stacked dielectric layers are used, then sufficient galvanic isolation between high voltage and low voltage components is achieved, but the device footprint and vertical dimensions increase excessively
Solution Approach 1:
The patent transitions from vertical stacking of dielectric layers to a lateral arrangement where isolation structures are positioned side-by-side in the same plane. The isolation layer extends laterally between the high voltage and low voltage components, providing galvanic isolation without increasing vertical height. This dimensional change from vertical to lateral configuration directly resolves the contradiction by maintaining isolation effectiveness while reducing device footprint.
Solution Approach 2:
The patent divides the isolation function into separate lateral isolation structures positioned between high voltage and low voltage components, rather than using a single vertical stack. Each isolation structure (including isolation layers, trenches, and dielectric regions) is segmented and positioned laterally adjacent to the components it isolates, enabling distributed isolation that reduces overall device volume while maintaining effective galvanic separation.
2Power
If operating voltages are increased to meet industry demands, then higher performance is achieved, but the space required for galvanic isolation increases
Solution Approach 1:
The patent applies different dielectric materials and isolation structures in specific local regions where high voltage stress occurs. High-k dielectric materials are positioned in regions requiring enhanced isolation, while lower-k materials are used in other areas. This localized optimization allows the structure to withstand higher operating voltages without proportionally increasing the total isolation space required.
Solution Approach 2:
The patent employs nested isolation structures where isolation layers are positioned within trenches, and additional dielectric regions are nested within existing structures. Multiple isolation functions are combined in nested configurations, allowing adequate isolation for high voltage operation to be achieved within a compact lateral footprint by utilizing three-dimensional nesting rather than simple lateral expansion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for smaller device footprints and reduced dimensions on IC chips while maintaining effective galvanic isolation between circuits, enabling efficient signal transmission without direct current flow and reducing the complexity of vertical dielectric layer stacks.
Implementation Method 1
the second electrode is isolated from the first electrode by the isolation layer
Implementation Method 2
an isolation layer in the substrate, the isolation layer has an upper surface and is positioned laterally adjacent to the first isolation structure
Data Source
AI summary
The present disclosure generally relates to semiconductor structures for capacitive isolation, and structures incorporating the same. More particularly, the present disclosure relates to capacitive isolation structures for high voltage applications. The present disclosure also relates to methods of forming structures for capacitive isolation and the structures incorporating the same. The disclosed semiconductor structures may enable a smaller device footprint and reduced dimensions of components on an IC chip, whilst ensuring galvanic isolation between circuits.