Semiconductor Package ESD and EMI Shielding via Insulated Metal Layer
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Solution Overview
Problem
Existing semiconductor packages face challenges in protecting internal chips and active/passive components from electrostatic discharge (ESD) and electromagnetic interference (EMI, as the meshed metal shields or metal foils connected to the ground circuit can conduct electrostatic charges, leading to potential damage and inadequate grounding for rapid charge release.
Innovation Solution
A semiconductor package design featuring a substrate unit with a ground structure and I/O structure, where semiconductor components are electrically connected to both, covered with an encapsulant, and a metal layer is formed on exposed surfaces, electrically insulated from the ground structure to prevent ESD and provide EMI shielding by connecting to a circuit substrate's ground system through conductive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a meshed metal shield or metal foil is electrically connected to the ground circuit to provide EMI shielding, then EMI shielding effect is improved, but electrostatic charges can be conducted through the ground circuit to the chip and active/passive components causing ESD damage
Solution Approach 1:
The package structure is divided into two separate electrical systems: one for EMI shielding (metal shield connected to substrate ground) and one for ESD protection (ESD pad with direct ground connection). This segmentation allows each system to perform its function independently without interfering with the other, resolving the contradiction between EMI shielding and ESD protection
Solution Approach 2:
The ESD pad acts as an intermediary element that provides a dedicated low-impedance path to ground for electrostatic charges. By introducing this intermediate component, ESD currents are diverted away from the ground circuit that connects to the metal shield, preventing ESD damage while maintaining EMI shielding effectiveness
2Area of stationary object
If the electrical connecting path from the metal shield to the system ground is made long to cover more area, then EMI shielding coverage is improved, but the grounding effect is adversely affected and electrostatic charges cannot be released rapidly
Solution Approach 1:
The grounding path is segmented into two separate paths: a long path for the metal shield to achieve wide EMI shielding coverage, and a short direct path for the ESD pad to achieve rapid charge release. This segmentation allows both requirements to be satisfied simultaneously without compromising either shielding coverage or discharge speed
Solution Approach 2:
The ESD protection is added in a different dimensional approach - rather than extending the metal shield's ground connection, a separate ESD pad structure is introduced with its own dedicated ground connection. This dimensional separation allows the ESD path to be optimized for speed while the shield path is optimized for coverage
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 prevents electrostatic discharge to semiconductor components and provides EMI shielding by isolating electrostatic charges from the ground structure and connecting the metal layer to the circuit substrate's ground system, ensuring the protection of internal components from damage and interference.
Implementation Method 1
a metal layer disposed on exposed surfaces of the encapsulant and side surfaces of the substrate unit and electrically insulated from the ground structure of the substrate unit... provides EMI shielding by connecting to a circuit substrate's ground system
Implementation Method 2
effectively prevents electrostatic discharge to semiconductor components and provides EMI shielding by isolating electrostatic charges from the ground structure and connecting the metal layer to the circuit substrate's ground system
Data Source
AI summary
A package having ESD (electrostatic discharge) and EMI (electromagnetic interference) preventing functions includes: a substrate unit having a ground structure and an I/O structure disposed therein; at least a semiconductor component disposed on a surface of the substrate unit and electrically connected to the ground structure and the I/O structure; an encapsulant covering the surface of the substrate unit and the semiconductor component; and a metal layer disposed on exposed surfaces of the encapsulant and side surfaces of the substrate unit and electrically insulated from the ground structure, thereby protecting the semiconductor component against ESD and EMI so as to improve the product yield and reduce the risk of short circuits.