Carbon Nanofiber Capacitor Structure for High-Density IC Packages
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Solution Overview
Problem
Current integrated circuit (IC) packages face challenges in achieving high capacitance density due to limitations in existing capacitor form factors, such as metal-insulator-metal (MIM) and multi-layer ceramic capacitors, which struggle to support increasing power delivery needs and processor operating frequencies.
Innovation Solution
The use of carbon nanofiber capacitors with high aspect ratio electrode contacts provides high capacitance densities, up to 650 nanofarad per square millimeter, by adjusting the size and spacing of carbon nanofibers to balance capacitance density and mechanical strength, and integrating these capacitors into the package substrate during fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional MIM or multi-layer ceramic capacitors are used, then the package structure is simple to manufacture, but the capacitance density is insufficient to support increasing power delivery needs
Solution Approach 1:
The patent transitions from planar capacitor structures to three-dimensional vertically-oriented carbon nanofiber arrays. The nanofibers extend perpendicular to the substrate surface, creating a vertical dimension for capacitance accumulation that dramatically increases capacitance density within the same footprint area.
Solution Approach 2:
The carbon nanofiber arrays form a porous three-dimensional network structure with high surface area-to-volume ratio. This porous architecture provides extensive electrode surface area for charge storage while maintaining structural integrity and enabling efficient ion transport throughout the capacitor volume.
2Quantity of substance
If carbon nanofiber capacitors with high aspect ratio electrode contacts are used, then capacitance density increases, but mechanical strength may be compromised
Solution Approach 1:
The patent employs composite structures combining carbon nanofibers with supporting matrices or integrated with substrate structures. The carbon nanofibers provide high surface area for capacitance, while the composite architecture and integration with rigid substrate elements provide the necessary mechanical strength and structural stability.
Solution Approach 2:
The carbon nanofibers are integrated within and coupled to the substrate structure, with the nanofiber arrays nested within the package substrate architecture. This nesting approach allows the nanofibers to benefit from the mechanical support of the surrounding substrate and encapsulating layers while maintaining their high aspect ratio configuration for maximum capacitance density.
3Productivity
If capacitor size is reduced to increase interconnect densities, then integration density improves, but power delivery capability may be insufficient
Solution Approach 1:
By orienting capacitors vertically and utilizing the third dimension for capacitance accumulation, the patent achieves high capacitance density in a compact footprint. This allows more capacitors to be integrated in the same planar area without compromising individual capacitor performance, thereby supporting both high interconnect density and adequate power delivery capability.
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AI summary
Carbon nanofiber capacitor apparatus and related methods are disclosed herein. An example apparatus includes an integrated circuit package substrate, and a capacitor provided in the integrated circuit package substrate. The capacitor includes a carbon fiber array, a dielectric film positioned on the carbon fiber array, and an electrode film positioned on the dielectric film.