Metal Lid Shielding Semiconductor Package EMI
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Solution Overview
Problem
Current semiconductor packages lack effective shielding against electromagnetic interference (EMI) and radio frequency (RF) interference, particularly in densely packed electronic devices, as existing shielding techniques are costly, complex, and often ineffective in sharing a common ground potential with circuit devices.
Innovation Solution
A semiconductor package design that utilizes a metal lid coupled to metalized areas on the die or a redistribution layer to form a Faraday shield, establishing electrical continuity with the die pad and lid to create a common ground potential, thereby effectively shielding active circuitry from EMI/RF interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If external shielding cans or cages are added during board level assembly, then EMI/RF shielding is provided, but manufacturing cost increases by up to 15% and device complexity increases
Solution Approach 1:
The patent merges the shielding function with existing package components by coupling the metal lid to the leadframe, creating an integrated shield structure. This eliminates the need for separate external shielding cans or cages, thereby reducing device complexity and manufacturing cost while maintaining EMI/RF shielding effectiveness.
Solution Approach 2:
The metal lid serves multiple functions: it provides mechanical protection for the package and simultaneously acts as an EMI/RF shield when coupled to the leadframe. This multi-functionality eliminates the need for dedicated shielding components, reducing both complexity and cost.
2Object-affected harmful factors
If shielding cans or cages are added during board level assembly, then EMI/RF shielding is provided, but manufacturing cost increases by up to 15%
Solution Approach 1:
The shielding function is merged with the package structure itself through the metal lid-leadframe coupling, eliminating the need for separate shielding components that would increase manufacturing cost. The shield is created using existing package materials and assembly processes.
Solution Approach 2:
The package structure provides its own shielding capability through the metal lid coupled to the leadframe, eliminating the need for external shielding services or components. The package is self-shielding, reducing manufacturing complexity and cost.
3Reliability
If the metal lid is coupled to metalized areas on the die or redistribution layer, then a common ground potential is established, but manufacturing precision requirements increase
Solution Approach 1:
Metalized areas are prepared on the die or redistribution layer during wafer fabrication before package assembly. This preliminary preparation ensures that when the metal lid is coupled to the leadframe, electrical continuity and common ground potential are automatically established without requiring additional precision operations.
Solution Approach 2:
The leadframe serves as an intermediary component that couples the metal lid to the metalized areas on the die or redistribution layer. This intermediary structure facilitates electrical continuity and common ground potential establishment while accommodating manufacturing tolerances.
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
This design provides effective shielding against EMI/RF interference across a wide frequency range, including high frequencies like 1-2 GHz, while minimizing manufacturing costs and complexity by utilizing existing package components, and ensuring all internal package elements are at the same electrical potential.
Implementation Method 1
a metal lid coupled to one or more prescribed metal features of the leadframe of the package to form a shield that effectively surrounds the active circuitry, thus creating a type of Faraday shield
Implementation Method 2
establishing electrical continuity with the die pad and lid to create a common ground potential
Data Source
AI summary
In one embodiment a semiconductor package includes a metal lid configured as a shield that effectively surrounds the active circuitry, and thus forms a type of Faraday shield. The lid is electrically coupled to a metalized area located on the surface of the active circuitry, or to an additional metalized die. Appropriate interconnect methods between the lid and the metalized die or metalized area include, but are not restricted to, wire bonding, bumps, tabs, or similar techniques.