TSV Shielding via Well Regions for High-Frequency Signal Integrity
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Solution Overview
Problem
Conventional through-substrate via (TSV) structures in integrated circuit devices suffer from high capacitance, leading to noise coupling and signal loss due to their large size, which affects the transmission of high-frequency signals.
Innovation Solution
The formation of well regions, specifically n-well and p-well regions, around TSVs to encircle and shield them, reducing the equivalent capacitance and coupling between TSVs and semiconductor substrates, thereby minimizing signal and noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TSV structure is used, then signal routing through substrate is achieved, but high capacitance causes noise coupling and signal loss
Solution Approach 1:
A waveguide structure is introduced as an intermediary between the TSV and the substrate. The waveguide includes a first portion extending from the TSV and a second portion extending into the substrate, with a gap between them. This intermediary structure reduces direct capacitive coupling while maintaining signal transmission functionality.
Solution Approach 2:
The signal transmission path is segmented into multiple portions: the TSV, the first waveguide portion, the gap region, and the second waveguide portion. This segmentation breaks the direct capacitive coupling path while maintaining electrical connectivity through the structured waveguide elements.
2Object-affected harmful factors
If TSV size is reduced, then capacitance is reduced, but signal routing capability is compromised
Solution Approach 1:
The waveguide structure extends the signal path into the vertical dimension by creating portions that extend into the substrate. This dimensional extension allows the signal to bypass the high-capacitance region while maintaining routing capability, effectively decoupling the capacitance issue from the signal transmission function.
Solution Approach 2:
The waveguide structure is nested within the substrate, with the first portion extending from the TSV and the second portion extending into the substrate. This nested configuration allows the signal to traverse through the substrate volume rather than relying solely on surface-level TSV connections, reducing capacitive effects.
3Object-affected harmful factors
If isolation layer is added between TSV and substrate, then some coupling is reduced, but capacitor effect remains due to TSV and substrate acting as capacitor plates
Solution Approach 1:
The waveguide structure serves as an intermediary that physically separates the TSV from direct substrate contact. The gap between the first and second waveguide portions creates an additional isolation mechanism beyond the isolation layer, further reducing the capacitor effect formed by the TSV and substrate acting as plates.
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
The use of well regions effectively reduces signal and noise coupling, allowing for the propagation of high-frequency signals with reduced propagation loss and maintaining the integrity of RF signals, while also enabling the formation of electro-static discharge devices without occupying additional chip area.
Implementation Method 1
capacitor 108 is formed, with TSV 102 and semiconductor substrate 106 acting as the capacitor plates of capacitor 108, and isolation layer 104 acting as the capacitor insulator
Data Source
AI summary
A device includes a semiconductor substrate of a first conductivity type, wherein the semiconductor substrate comprises a first surface and a second surface opposite the first surface. A through-substrate via (TSV) extends from the first surface to the second surface of the semiconductor substrate. A well region of a second conductivity type opposite the first conductivity type encircles the TSV, and extends from the first surface to the second surface of the semiconductor substrate.