Shielding Structure for Crosstalk Reduction in Integrated Circuits
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Solution Overview
Problem
High-frequency circuits integrated on the same substrate experience severe crosstalk and interference issues, degrading the performance and linearity of active circuits like low noise amplifiers due to proximity with high-speed logic or power amplifiers, leading to signal integrity and circuit performance degradation.
Innovation Solution
A shielding structure is formed on the substrate surrounding the active circuit, comprising heavy ion-doped regions and metal stacks connected to ground voltage, with a top metal layer, to effectively block crosstalk and interference paths through the substrate and air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If various kinds of circuits are integrated on the same substrate to increase functionality, then device versatility is improved, but crosstalk and interference between circuits increase
Solution Approach 1:
The substrate is segmented into different functional regions separated by shielding structures. Heavy ion-doped regions are introduced to divide and isolate circuit areas, creating distinct zones for RF circuits, high-speed logic, and other sensitive circuits. This segmentation prevents electromagnetic interference between adjacent circuits while maintaining overall device functionality.
Solution Approach 2:
Shielding structures serve as intermediary elements between adjacent circuits. These structures, comprising heavy ion-doped regions and metal stacks, act as mediators that block electromagnetic fields and prevent direct interference between noisy sources like power amplifiers and sensitive circuits like low noise amplifiers.
2Area of stationary object
If noisy sources such as power amplifiers are placed adjacent to active circuits to reduce device area, then area is reduced, but signal integrity degrades
Solution Approach 1:
Different regions of the substrate are assigned different local qualities through selective heavy ion doping. Areas surrounding sensitive active circuits are doped to create high-impedance regions that locally block electromagnetic fields, while noisy sources like power amplifiers are placed in regions with different doping characteristics. This local quality differentiation allows close proximity placement while maintaining signal integrity.
Solution Approach 2:
The electrical parameters of the substrate are changed by introducing heavy ion-doped regions with different doping concentrations and depths. These parameter changes create regions with varying electromagnetic properties, allowing the substrate to simultaneously support both noisy power amplifiers and sensitive active circuits in close proximity without degradation of signal integrity.
3Speed
If high-speed logic circuits operate at high frequencies to improve processing speed, then processing speed is improved, but harmonics contaminate RF signal bands
Solution Approach 1:
The heavy ion-doped regions, which inherently attenuate electromagnetic signals, are strategically positioned to convert the harmful harmonic emissions from high-speed logic circuits into beneficial shielding effects. The doped regions act as frequency-selective barriers that allow desired signals to pass while blocking harmonic frequencies, thus converting a potential interference source into a protected environment for RF circuits.
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 shielding structure significantly reduces crosstalk and interference, maintaining signal integrity and circuit performance by grounding electric fields and isolating the active circuit from neighboring noisy sources, particularly beneficial in System on Chip (SoC) devices.
Implementation Method 1
The shielding structure comprises a first heavy ion-doped region, a first metal stack, a second heavy ion-doped region, a second metal stack and a top metal
Implementation Method 2
The first metal stack is formed on the first heavy ion-doped region of the substrate, wherein the first metal stack is connected to a ground voltage
Data Source
AI summary
An electronic device includes a substrate, an active circuit, and a shielding structure. The active circuit is formed on the substrate. The shielding structure is disposed surrounding the active circuit, and includes a first heavy ion-doped region, first metal stack, second heavy ion-doped region, second metal stack and top metal. The first heavy ion-doped is formed in the substrate and located at a first side of the active circuit. The first metal stack is formed on the first heavy ion-doped region of the substrate, wherein the first metal stack is connected to a ground voltage. The second heavy ion-doped region is formed in the substrate and located at a second side of the active circuit. The second metal stack is formed on the second heavy ion-doped region of the substrate. The top metal is formed on the first metal stack and second metal stack and passing over the active circuit.