Leadless Semiconductor Package Shielding With Full Metal Enclosure
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Solution Overview
Problem
Existing semiconductor devices, particularly leadless packages like QFN designs, suffer from inadequate electromagnetic (EM) shielding, leading to susceptibility to interference, especially in high-sensitivity applications, with current solutions providing only partial shielding and high costs.
Innovation Solution
A full-enclosure EM shielding is achieved by combining a plated shield with a modified leadframe peripheral ring structure and grounding arrangement, involving cuts and metal plating to form a complete enclosure around the module, ensuring all components are shielded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If partial shielding solutions are used for selected components, then specific layout protection is achieved, but shielding completeness and reproducibility deteriorate
Solution Approach 1:
The shielding structure is divided into multiple segments: a top shield plate covering the top surface, side shield plates covering the side surfaces, and a peripheral ring structure connecting them. This segmentation allows each component to be optimized independently while maintaining overall shielding effectiveness and reproducibility across different layouts.
Solution Approach 2:
The peripheral ring structure serves multiple functions: it provides mechanical support for the shield plates, acts as an electromagnetic shield itself, provides grounding paths, and enables reproducible assembly across different device layouts. This multi-functionality resolves the contradiction between customized protection and reproducibility.
2Object-affected harmful factors
If high conductivity shielding materials are used, then EM radiation protection is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The shielding structure uses thin metallic plates and films instead of bulky shielding materials. The top shield plate and side shield plates are implemented as thin conductive layers that provide effective EM shielding while minimizing structural complexity and material usage.
Solution Approach 2:
The shielding system combines multiple materials with different properties: high conductivity materials for the shield plates, insulating materials for spacing and support structures, and grounding materials for the peripheral ring. This composite approach optimizes shielding effectiveness while managing complexity through functional specialization.
3Reliability
If complete enclosure shielding is implemented, then EM shielding performance is significantly improved, but manufacturing process complexity increases
Solution Approach 1:
The peripheral ring structure is prepared in advance with integrated grounding paths and mounting features. The top and side shield plates are pre-positioned and secured to the peripheral ring before final assembly, simplifying the manufacturing process while achieving complete enclosure shielding.
Solution Approach 2:
Multiple shielding functions are merged into integrated components: the peripheral ring combines structural support, electromagnetic shielding, and grounding functions. The top and side shield plates are connected through the peripheral ring to form a unified shielding enclosure, reducing the number of separate assembly steps.
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 solution provides significantly improved EM shielding performance, effectively protecting sensitive components from electromagnetic interference, especially in high-frequency and high-speed applications.
Implementation Method 1
controlled metal plating or other shielding is applied over the module, into contact with the exposed peripheral ring
Implementation Method 2
these materials absorb or reflect unwanted EM energy, preventing the energy from reaching the sensitive parts of the device
Data Source
AI summary
Structures and methods for full-enclosure electromagnetic shielding of leadless semiconductor packages provide complete module-level electromagnetic shielding by combining plated shielding with proposed modified leadframe peripheral structure and ground pad grounding. A first cut into an overmolded leadless module exposes the peripheral ring of the leadframe; then, with controlled metal plating a full shielding enclosure is formed over the top of the package into contact with the exposed peripheral ring. The proposed approach provides complete electromagnetic shielding for the module with significantly improved electromagnetic shielding performance. The full enclosure shielding solution is especially important for high frequency and high-speed application and sensing products with high sensitivity to electromagnetic interference.