Shielded Lead Frame Package EMI Reduction
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Solution Overview
Problem
Semiconductor devices face challenges in providing effective electromagnetic interference (EMI) shielding without increasing package size or cost, particularly for overmolded RF modules used in wireless devices.
Innovation Solution
A radio-frequency (RF) module with a lead-frame package is shielded using a metal-based covering applied over a portion of the package, with at least one pin exposed from the overmold compound and connected to a ground plane, utilizing multiple layers of metallic compositions to enhance EMI shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal-based covering is applied over the lead-frame package to provide EMI shielding, then EMI protection is improved, but package size and cost may increase
Solution Approach 1:
The patent applies metal-based covering selectively over specific portions of the lead-frame package rather than the entire package. The covering is applied to surfaces where EMI shielding is most needed, such as the top and sides of the package, while leaving the bottom surface exposed for mounting purposes. This localized application provides effective EMI protection for the sensitive RF components while minimizing the increase in overall package volume.
Solution Approach 2:
The patent implements partial EMI shielding by covering only the necessary portions of the lead-frame package. The metal-based covering is applied to all but one side of the package, providing sufficient EMI protection for the RF module without completely enclosing the entire package. This partial action approach achieves adequate shielding effectiveness while avoiding unnecessary material usage and package size increase.
2Object-affected harmful factors
If a metal-based covering is applied over the lead-frame package to provide EMI shielding, then EMI protection is improved, but manufacturing cost may increase
Solution Approach 1:
The patent reduces manufacturing cost by applying the metal-based covering only to specific portions of the lead-frame package where EMI shielding is most critical. This selective application reduces the total amount of expensive metallic material required compared to complete package encasement, while still providing effective EMI protection for the RF components.
Solution Approach 2:
The patent employs cost-effective metal-based covering materials and application methods suitable for mass production. The metal-based covering can be applied through conventional manufacturing processes such as electroplating, electroless plating, or metallic painting, which are relatively inexpensive and scalable. The covering provides sufficient EMI protection without requiring expensive multi-layer composite materials or complex assembly procedures.
3Object-affected harmful factors
If multiple layers of metallic compositions are used in the covering, then EMI shielding effectiveness is improved, but device complexity increases
Solution Approach 1:
The patent utilizes multiple layers of metallic compositions with different properties to enhance EMI shielding effectiveness. The multi-layer structure may include combinations of metals such as copper, nickel, and gold, or metallic paints with different conductive properties. Each layer contributes to blocking different frequencies or aspects of electromagnetic interference, providing superior protection through material composition rather than structural complexity.
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 effectively reduces EMI, protecting sensitive components within wireless devices by ensuring all but one side of the lead-frame package is covered, with the metal-based covering connected to a ground plane, thereby improving the RF module's performance without increasing the package size or cost.
Implementation Method 1
the metal-based covering in contact with the at least one pin... effectively reduces EMI, protecting sensitive components within wireless devices
Data Source
AI summary
Devices and methods are disclosed, related to shielding and packaging of radio-frequency (RF) devices on substrates. In some embodiments, a method for providing electro-magnetic interference shielding for a radio-frequency module can include applying a metal-based covering over a portion of a lead-frame package, the package having a plurality of pins with at least one pin exposed from overmold compound and in contact with the metal-based covering. The method can also include mounting the lead-frame package on a substrate. The method can further include connecting the metal-based covering to a ground plane of the substrate.