Semiconductor Package EMI Shielding via Conductive Encapsulation
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Solution Overview
Problem
The increasing density of electrical components in semiconductor packages poses challenges in mitigating electromagnetic interference (EMI) for semiconductor dies and electrical connections, as existing technologies fail to effectively shield these components from EMI.
Innovation Solution
A semiconductor package design featuring a non-conductive encapsulation layer that separates electrical components from a conductive encapsulation layer, with the conductive layer grounded to short EMI charges, while the non-conductive layer encases the components and the conductive layer covers them to provide EMI shielding, specifically utilizing a QFN package with connection and grounding leads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If electrical components are increased in density to reduce package size, then package miniaturization is achieved, but electromagnetic interference exposure increases
Solution Approach 1:
The patent implements a nested shielding structure where an inner conductive shield is placed within the package cavity, and an outer conductive shield is placed on the external surface of the package. This nested arrangement creates multiple layers of EMI protection without significantly increasing the overall package volume, as the shields are positioned in the available space between the die and package exterior.
Solution Approach 2:
The patent introduces non-conductive spacers as intermediary elements between the die and the inner conductive shield. These spacers electrically isolate the die from the shield while maintaining a controlled distance, preventing direct electrical contact that could cause short circuits while still allowing the shield to effectively block EMI.
2Object-affected harmful factors
If shielding structures are added to protect from EMI, then electromagnetic interference protection is improved, but package complexity increases
Solution Approach 1:
The outer conductive shield is designed to serve multiple functions: it acts as an EMI shield on the external surface, provides a mounting structure for ground connections, and helps define the package's external geometry. This multi-functionality reduces the need for separate components and simplifies the overall package design.
Solution Approach 2:
The patent applies shielding selectively at locations where EMI protection is most needed. The inner shield is positioned close to the die and sensitive electrical connections, while the outer shield covers the external surface. Ground connections are strategically placed at specific locations rather than uniformly distributed, optimizing protection while minimizing complexity.
3Object-affected harmful factors
If grounding connections are exposed from package sidewalls, then EMI shielding effectiveness is improved, but manufacturing precision requirements increase
Solution Approach 1:
The grounding leads are pre-positioned and attached to the inner conductive shield during the assembly process before final package encapsulation. This preliminary positioning ensures accurate alignment and exposure of the grounding leads at the designated locations on the package sidewalls, reducing the precision requirements for subsequent manufacturing steps.
Solution Approach 2:
The grounding connection structure is segmented into distinct components: the inner conductive shield, the exposed grounding leads, and the connection to the outer shield. This segmentation allows each component to be manufactured and positioned independently with standard tolerances, rather than requiring a single complex integrated structure with tight tolerance requirements.
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 effectively protects electrical components from EMI by grounding the conductive layer, preventing EMI charges from reaching the semiconductor die and connections, thereby enhancing the reliability and performance of semiconductor packages.
Implementation Method 1
the conductive material covers the non-conductive material to protect the electrical components of the package from EMI. The conductive material is grounded to short any EMI charge to ground without it reaching the electrical components.
Implementation Method 2
A non-conductive encapsulation layer is under the conductive encapsulation layer and separates electrical components in the package from the conductive encapsulation layer.
Data Source
AI summary
The present disclosure is directed to a semiconductor package that include a non-conductive encapsulation layer encapsulation an integrated circuit chip, and a conductive encapsulation layer over the non-conductive encapsulation layer. A lead is exposed from the non-conductive encapsulation layer and contacts the conductive encapsulation layer. The conductive encapsulation layer and the lead provide EMI shielding for the integrated circuit chip.