Tunable Interconnect Structures for IC Delay Adjustment
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Solution Overview
Problem
Current transmission line interconnect structures in ICs have fixed characteristics, making it difficult to modify delay and characteristic impedance, which limits reconfigurability and performance, especially due to parasitics associated with conventional FEOL switches.
Innovation Solution
The introduction of tunable interconnect structures using switchable conductors, capacitance plates, and inductance return lines with programmable wiring switches in the BEOL, allowing for dynamic adjustment of delay and impedance without relying on FEOL components, enabling reconfigurability and fine-tuning of transmission lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional FEOL switches are used to make the interconnect reconfigurable, then the interconnect can be tuned, but parasitics increase and tunability decreases
Solution Approach 1:
The patent extracts the switching function from the FEOL (front-end-of-line) and relocates it to the BEOL (back-end-of-line). This separation removes the parasitic-heavy FEOL switches from the signal path, achieving reconfigurability through BEOL wiring switches that have lower parasitics and less impact on signal integrity.
Solution Approach 2:
The patent introduces BEOL wiring switches as intermediary elements between the signal conductor and ground. These wiring switches serve as mediators that enable tuning of the interconnect characteristics without directly interfering with the signal path in the same way FEOL switches do, thereby reducing parasitic effects.
2Adaptability or versatility
If conventional FEOL switches are used to modify interconnect characteristics, then tuning capability is achieved, but tunability decreases due to parasitics
Solution Approach 1:
The patent extracts the switching function from the FEOL (front-end-of-line) and relocates it to the BEOL (back-end-of-line). This separation removes the parasitic-heavy FEOL switches from the signal path, achieving reconfigurability through BEOL wiring switches that have lower parasitics and less impact on signal integrity.
Solution Approach 2:
The patent employs BEOL wiring switches that are simpler, less complex structures compared to FEOL switches. These wiring switches are easier to fabricate and integrate into existing CMOS processes, providing a cost-effective and less invasive solution for achieving tunability without the complexity and parasitics of conventional FEOL switching devices.
3Ease of manufacture
If the interconnect structure is made fixed during fabrication, then manufacturing is simpler, but reconfigurability is lost
Solution Approach 1:
The patent segments the interconnect structure into multiple conductors (signal conductor, first ground line conductor, second ground line conductor) with switchable elements distributed along the transmission line. This segmentation allows different portions of the interconnect to be independently controlled, enabling reconfigurability while maintaining a relatively simple fabrication process using standard CMOS BEOL layers.
Solution Approach 2:
The patent transforms the static, fixed interconnect structure into a dynamic, reconfigurable one by incorporating switchable conductors and capacitance plates that can be selectively activated. This allows the interconnect characteristics to be dynamically adjusted after fabrication, providing adaptability without complicating the base manufacturing process.
Data Source
AI summary
Tunable interconnect structures, integrated circuits containing the tunable interconnect structures and methods of manufacturing the same are disclosed. The interconnect transmission line structure includes a signal conductor and a plurality of conductors in proximity to the signal conductor. The structure further includes one or more switchable conductors in proximity to at least the signal conductor. The one or more switchable conductors has a programmable wiring switch with a terminal connected to the one or more switchable conductors and another terminal connected to ground.