Semiconductor Package EMI Shielding via Conductive Structure
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Solution Overview
Problem
Semiconductor packages face challenges in effectively shielding against electromagnetic interference (EMI) due to high contact resistance values between EMI shielding layers and grounded interconnection layers, especially when the package substrate thickness is reduced, leading to degradation of the EMI shielding effect.
Innovation Solution
A semiconductor package configuration that includes a conductive structure with exposed side surfaces on the substrate and an EMI shielding layer in contact with these surfaces, which reduces the contact resistance and improves the EMI shielding effect by using an oxidation-resistant material for the conductive structure, such as stainless steel, and ensuring the EMI shielding layer directly contacts the conductive structure fingers and frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the package substrate thickness is reduced, then the device size is decreased, but the contact resistance between EMI shielding layer and grounded interconnection layer increases
Solution Approach 1:
The patent introduces a conductive structure as an intermediary element between the EMI shielding layer and the grounded interconnection layer. This conductive structure includes a conductive frame and conductive fingers that extend from the frame to contact the EMI shielding layer, providing a reliable conductive path that compensates for the reduced substrate thickness and prevents increased contact resistance.
Solution Approach 2:
The patent extends the conductive structure vertically by adding conductive fingers that protrude upward to contact the EMI shielding layer. This dimensional extension creates additional contact points and pathways, ensuring low contact resistance even when the substrate thickness is reduced, thereby resolving the contradiction between miniaturization and electrical reliability.
2Reliability
If conventional conductive materials are used, then the contact resistance may be low initially, but oxidation occurs leading to increased contact resistance over time
Solution Approach 1:
The patent employs a composite material structure where the conductive frame and fingers are made of oxidation-resistant materials such as stainless steel or aluminum alloy. These materials provide both the necessary electrical conductivity for low contact resistance and inherent oxidation resistance to maintain reliability over time, addressing both aspects of the contradiction simultaneously.
3Device complexity
If the EMI shielding layer is made to contact the substrate directly, then the structure is simplified, but the contact resistance increases especially in thin substrates
Solution Approach 1:
The conductive structure serves as a mediator between the EMI shielding layer and the substrate, providing a dedicated low-resistance conductive path. The conductive frame and fingers create multiple contact points that ensure reliable electrical connection without requiring direct contact between the EMI shielding layer and the substrate, thus maintaining low contact resistance while managing 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
This configuration achieves a stable and low contact resistance between the conductive structure and the EMI shielding layer, enhancing the EMI shielding effect without the need for high electric conductivity materials and reducing the risk of oxidation, thus maintaining effective shielding regardless of substrate thickness.
Implementation Method 1
an electromagnetic interference (EMI) shielding layer covering the chip and the conductive structure
Data Source
AI summary
A semiconductor package may include a chip disposed on a substrate, a conductive structure disposed on the substrate to include a conductive structure frame including a side surface facing at least one side surface of the chip and to include conductive structure fingers extending from the conductive structure frame toward an edge of the substrate, and an electromagnetic interference (EMI) shielding layer covering the chip and the conductive structure and contacting a side surface of an end of one or more of the conductive structure fingers.