Parallel Capacitor Elements with Internal Rewiring for Low Impedance
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Solution Overview
Problem
Existing decoupling capacitors on circuit substrates face challenges in reducing impedance in the wide high-frequency band (GHz band) due to parasitic inductances from lead routing and limited reduction in resonance frequency, making it difficult to stabilize power supply voltage and reduce high-frequency noise effectively.
Innovation Solution
A capacitor part design featuring a substrate with multiple capacitor elements connected in parallel, where the number of connecting vias and electrode divisions are varied to cancel out inductance, forming a parallel circuit with reduced impedance across a wide high-frequency range, utilizing fine rewiring layers and high photolithography technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a plurality of capacitor parts are mounted onto the circuit substrate to be connected electrically in parallel, then the impedance can be reduced in the wide high-frequency range by the synthesized impedance, but relatively large parasitic inductances exist between the leads
Solution Approach 1:
Multiple capacitor elements are integrated onto a single substrate and electrically connected in parallel through internal rewiring layers, merging their impedance-reducing effects while minimizing parasitic inductance by eliminating external lead connections
Solution Approach 2:
The substrate with rewiring layers acts as an intermediary structure that provides low-inductance electrical connection between multiple capacitor elements, replacing the high-inductance external lead routing
2Object-affected harmful factors
If the wiring distance between the LSI chip and the decoupling capacitor is set shortest by arranging the decoupling capacitor immediately under the LSI chip, then the parasitic inductance is reduced, but there is a limit to the reduction and it is extremely difficult to reduce the impedance in the wide high-frequency band (GHz band)
Solution Approach 1:
The decoupling capacitor is segmented into multiple capacitor elements connected in parallel, each contributing to impedance reduction across different frequency ranges, thereby extending the effective high-frequency band beyond what a single capacitor can achieve
Solution Approach 2:
The solution moves from optimizing a single capacitor's position (one-dimensional placement optimization) to integrating multiple capacitor elements on a substrate with controlled impedance paths (multi-dimensional structural optimization), enabling broader frequency range performance
Data Source
AI summary
A capacitor parts of the present invention, includes a substrate, a plurality of capacitor elements arranged on the substrate and composed of a lower electrode, a dielectric layer, and an upper electrode respectively, a lower electrode rewiring layer formed over the plurality of capacitor elements and connected electrically to lower electrodes of the plurality of capacitor elements respectively to act as a common electrode, and an upper electrode rewiring layer formed over the plurality of capacitor elements and connected electrically to upper electrodes of the plurality of capacitor elements respectively to act as another common electrode, wherein the plurality of capacitor elements are connected electrically in parallel in a state of the capacitor parts, thus, the impedance is reduced in a wide high-frequency band by changing impedances among the plurality of capacitor elements.