3D Shielding Structure with Feed-Through Capacitors for RF Isolation
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Solution Overview
Problem
Current electromagnetic shielding technologies for semiconductor substrates are inadequate in protecting against RF interference, particularly in high-frequency applications, as they lack effective feed-through connections and are incomplete due to structural holes, and do not utilize feed-through capacitors and transmission lines, leading to inefficiencies in shielding effectiveness.
Innovation Solution
A conductive shielding structure forming a 3D box around the circuit with a high doping bottom layer, via sidewalls, and a metal top layer, incorporating feed-through capacitors and transmission lines to provide power and signal connections while minimizing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional shielding structures are used without feed-through capacitors and transmission lines, then the shielding structure is simpler, but the shielding effectiveness is degraded due to incomplete coverage and signal leakage
Solution Approach 1:
The shielding structure is segmented into multiple functional components: a conductive shielding layer, feed-through capacitors for power connections, and transmission lines for signal connections. This segmentation allows each component to perform its specific function optimally while maintaining overall shielding effectiveness.
Solution Approach 2:
The feed-through capacitors and transmission lines are integrated within the shielding structure, with the capacitors embedded in the substrate and the transmission lines routed through the shielding layer. This nesting approach allows the shielding structure to accommodate necessary connections while maintaining its protective function.
2Reliability
If feed-through capacitors and transmission lines are integrated into the shielding structure, then power and signal connections are provided with minimal leakage, but the manufacturing process becomes more complex
Solution Approach 1:
The feed-through capacitors are formed during the substrate fabrication process before the shielding layer is applied. The transmission lines are also preliminarily routed and integrated into the substrate structure. This preliminary action allows these components to be manufactured as part of the standard substrate process, reducing overall manufacturing complexity.
Solution Approach 2:
The shielding layer is merged with the substrate structure, with the feed-through capacitors and transmission lines integrated into the same fabrication process. This combining approach allows all components to be manufactured together in a unified process flow, simplifying the overall manufacturing procedure.
3Reliability
If a complete 3D shielding box structure is formed with bottom layer, via sidewalls, and top layer, then shielding effectiveness is significantly improved, but the device complexity increases
Solution Approach 1:
The shielding structure transitions from a 2D planar layer to a 3D box structure by adding vertical via sidewalls that extend from the bottom layer to the top layer. This dimensional change creates a complete enclosed shielding volume, significantly improving isolation between circuit blocks while maintaining a compact form factor.
Solution Approach 2:
The shielding structure utilizes composite construction with different conductive materials and doping layers. The bottom layer uses heavily doped semiconductor material, the via sidewalls use conductive fill material, and the top layer uses metal interconnect material. This composite approach optimizes the electrical and shielding properties of each layer while integrating them into a unified structure.
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 proposed solution significantly improves isolation by up to 30 dB across a wide frequency range, effectively reducing coupling between circuit blocks and enhancing shielding effectiveness in high-frequency applications.
Implementation Method 1
a high doping bottom layer
Implementation Method 2
conductive shielding structure forming a 3D box around the circuit
Implementation Method 3
feed through capacitors and transmission lines to provide power and signal connections while minimizing leakage
Implementation Method 4
transmission lines for the AC signal connections
Data Source
AI summary
An electromagnetic shielding structure that includes a conductive structure surrounding and accommodating a circuit or a circuit device arranged on a substrate. At least one feed through device is associated with the conductive structure and provides signals to the circuit or circuit device. The method includes forming a shielding structure so that the shielding structure at least one of is at least partially arranged within the substrate and surrounds the circuit or circuit device and associating at least one feed through device with the shielding structure.