Semiconductor EMI Shielding via Wire Fence Structures
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Solution Overview
Problem
Existing semiconductor devices face challenges with Electro-Magnetic Interference (EMI) shielding methods that require additional space, are costly, and suffer from issues like flux creep and delamination, as well as difficulties in encapsulation and component inspection due to the need for large contact pads on the substrate surface.
Innovation Solution
A semiconductor device design featuring a substrate with metal layers and wire fence structures where metal wires form loops of varying heights, encapsulated with a mold compound, and a conductive coating applied to exposed portions of the wires for EMI shielding, eliminating the need for large contact pads and addressing encapsulation and inspection challenges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal shield is attached to the substrate surface, then EMI shielding is provided, but additional substrate space is required and encapsulation becomes difficult
Solution Approach 1:
The patent transitions the EMI shield from a two-dimensional surface attachment to a three-dimensional structure by forming metal wires that extend vertically from the substrate surface. These wires are then encapsulated within the mold compound, creating a volumetric shield that provides EMI protection without occupying additional substrate area. The shield effectively utilizes the vertical dimension and the encapsulation space to achieve shielding functionality.
2Reliability
If large contact pads are used on the substrate surface, then electrical connection to the shield is achieved, but substrate size increases
Solution Approach 1:
The patent uses thin metal wire structures instead of large planar contact pads to achieve electrical connection to the EMI shield. The metal wires act as flexible conductors that can be formed in compact configurations, connecting to small ground pads on the substrate. This wire-based approach provides sufficient electrical connectivity while minimizing the area required on the substrate surface compared to traditional large contact pads.
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 EMI shielding without increasing substrate size, reduces contact resistance, and allows for easier inspection and assembly by using a conductive coating on exposed wire loops, enhancing the overall efficiency and reliability of the semiconductor device.
Implementation Method 1
A conductive coating is applied to the mold compound and to the portion of the loop of the at least one metal wire exposed. EMI shielding is required on certain semiconductor devices in order to minimize EMI radiation from the semiconductor device.
Implementation Method 2
both ends of each of the first plurality of metal wires are coupled to at least one metal layer to form a loop of a first height. A second plurality of metal wires are provided, wherein both ends of each of the second plurality of metal wires are coupled to at least one metal layer to form a loop of a second height.
Data Source
AI summary
A semiconductor device has a substrate having a plurality of metal layers. A die coupled to the substrate. A first wire fence structure is formed on the substrate. A second wire fence structure is formed on the substrate. A mold compound is used for encapsulating the die, a first surface of the substrate, the first wire fence structure, and the second wire fence structure, wherein a top portion of at least one of the first wire fence structure or the second wire fence structure is exposed. A conductive coating is applied to the mold compound and to the portion of the at least one of the first wire fence structure or the second wire fence structure is exposed.