PCB High-Voltage Capacitor Structure With Concentric BEOL Electrodes
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Solution Overview
Problem
Conventional capacitor fabrication technologies face limitations in forming capacitors with high breakdown voltages as part of circuit board fabrication.
Innovation Solution
The integration of capacitors with enhanced breakdown voltage and low coupling capacitance is achieved by forming BEOL interconnect layers in a cylindrical shape with concentric electrodes, allowing for a uniform distribution of electric fields and reducing the area required for isolating contacts in FEOL processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capacitor fabrication techniques are used, then manufacturing simplicity is maintained, but breakdown voltage is insufficient
Solution Approach 1:
The capacitor structure embeds multiple functional elements within a unified cylindrical geometry. The concentric arrangement of high voltage and low voltage plates nested within the same BEOL interconnect structure allows high breakdown voltage capability without requiring separate fabrication processes, thus maintaining manufacturing simplicity while achieving high reliability
Solution Approach 2:
The invention transitions from planar capacitor layouts to a three-dimensional cylindrical configuration with concentric plates. This dimensional change enables uniform electric field distribution and higher breakdown voltage while utilizing the vertical stacking capability of BEOL processes, avoiding increased fabrication complexity
2Reliability
If conventional capacitor layouts are used, then manufacturing is simple, but coupling capacitance is high
Solution Approach 1:
The capacitor employs asymmetric plate configurations where the high voltage plate and low voltage plate have different geometries and positions within the cylindrical structure. This asymmetry, combined with strategic spacing, minimizes parasitic coupling capacitance between plates while maintaining a manufacturable structure using standard BEOL interconnect patterns
3Area of stationary object
If traditional capacitor configurations are used, then fabrication is straightforward, but isolation area is large
Solution Approach 1:
By transitioning to a vertical cylindrical capacitor structure stacked within BEOL layers, the design confines the capacitor footprint to a small lateral area. The isolation requirements are satisfied through vertical separation and shielding provided by intermediate metal layers and dielectric materials, reducing the lateral isolation area needed in FEOL processing
Solution Approach 2:
The BEOL interconnect layers serve multiple functions simultaneously: they provide electrical interconnection, form the capacitor structure, and provide isolation for FEOL devices. This multi-functionality eliminates the need for dedicated isolation structures, reducing the area required for isolating contacts in FEOL processing
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 enables the formation of capacitors with high breakdown voltage and low coupling capacitance, allowing for efficient integration with CMOS devices and reducing the area needed for isolating contacts, thereby improving the overall performance and efficiency of circuit board fabrication.
Implementation Method 1
a capacitor having first and second plates... a uniform distribution of the electric fields is achieved
Data Source
AI summary
Example embodiments include methods and apparatus for a structure having a capacitor, where the structure includes a plurality of inter-metal dielectric (IMD) layers above a substrate, a plurality of metal layers between respective IMD layers. In embodiments, BEOL metal regions and interconnects form plates of the capacitor. In example embodiments, lateral capacitors can be formed away from the substrate.