Galvanic Isolation Device Using Vertical Capacitors
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Solution Overview
Problem
Conventional capacitor-based galvanic isolation devices face challenges in advancing isolation capabilities with new semiconductor process nodes, leading to larger package footprints and increased costs due to the need for additional fabrication layers and die stacking, which restricts the integration of galvanic isolation features in modern technologies.
Innovation Solution
The use of a dielectric isolation layer with multiple layers and a re-enforced dielectric film between stacked IC dies, along with vertically oriented capacitors and inkjet printing techniques, allows for scalable voltage breakdown ratings and compact package designs, enabling efficient galvanic isolation without the need for extensive process node upgrades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capacitor-based galvanic isolation devices use additional fabrication layers and die stacking to advance isolation capabilities, then voltage breakdown protection is improved, but package footprint and manufacturing cost increase
Solution Approach 1:
The patent transitions from planar capacitor layouts to vertically-oriented capacitors that extend through the substrate thickness. This dimensional change allows the electric field to be oriented perpendicular to the substrate surface, enabling galvanic isolation functionality within the vertical dimension rather than requiring additional lateral area. The vertically-oriented capacitors utilize the substrate thickness as an effective dimension for isolation, thereby improving voltage breakdown protection without increasing package footprint.
Solution Approach 2:
The patent employs through-substrate vias that create conductive pathways through the substrate, effectively utilizing the substrate's internal volume and thickness. These vias allow the formation of vertically-oriented capacitors by providing conductive connections from the top to bottom surfaces, enabling the isolation structure to exploit the third dimension (depth) rather than being constrained to the two-dimensional planar surface.
2Reliability
If conventional capacitor-based galvanic isolation devices use additional fabrication layers to improve isolation capabilities, then voltage breakdown protection is improved, but manufacturing cost increases
Solution Approach 1:
The patent achieves enhanced voltage breakdown protection by orienting capacitors vertically through the substrate, utilizing the existing substrate thickness as an effective isolation dimension. This approach leverages the natural vertical dimension of the substrate rather than requiring additional fabrication layers, thereby improving isolation capabilities while avoiding the increased manufacturing costs associated with multi-layer fabrication processes.
Solution Approach 2:
The patent uses the substrate's existing structural dimensions (thickness, area) to create the isolation function, effectively copying the substrate's geometric properties for the isolation purpose. This eliminates the need for separate isolation layers or additional fabrication steps, reducing manufacturing complexity and cost while achieving the desired voltage breakdown protection.
3Productivity
If conventional galvanic isolation devices are integrated in modern technologies, then data transmission capability is improved, but integration is restricted due to larger package footprints
Solution Approach 1:
The patent enables integration of galvanic isolation in modern technologies by transitioning to vertically-oriented capacitors that utilize the substrate's thickness dimension. This dimensional change compresses the isolation functionality into the vertical direction, freeing up lateral package area for other circuit elements and enabling higher integration density while maintaining full data transmission capability across the isolation barrier.
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 approach provides enhanced voltage breakdown protection, reduced package size, and cost-effective integration of galvanic isolation, enabling safe and efficient data transmission across different voltage domains while maintaining compatibility with advanced semiconductor technologies.
Implementation Method 1
Energy or information can still be exchanged between the sections by other means, such as capacitance, induction, or electromagnetic waves
Implementation Method 2
The dielectric isolation layer may include several layers in order to provide redundancy and increased voltage breakdown capability
Implementation Method 3
The use of a dielectric isolation layer with multiple layers and a re-enforced dielectric film between stacked IC dies, along with vertically oriented capacitors
Data Source
AI summary
A galvanic isolation device includes a first integrated circuit (IC) die that has communication circuitry formed in a circuit layer below the top surface. A first conductive plate is formed on the IC die proximate the top surface, and is coupled to the communication circuitry. A dielectric isolation layer is formed over a portion of the top surface of the IC after the IC is fabricated such that the dielectric isolation layer completely covers the conductive plate. A second conductive plate is juxtaposed with the first conductive plate but separated by the dielectric isolation layer such that the first conductive plate and the second conductive plate form a capacitor. The second conductive plate is configured to be coupled to a second communication circuit.