Semiconductor Package Shielding Assembly for Solder Ball Crosstalk
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Solution Overview
Problem
Electrical performance degradation due to crosstalk coupling in semiconductor packages, particularly in advanced high-speed electronic semiconductor packages, is exacerbated by miniaturization, which reduces the pitch dimension of solder ball grid arrays and increases unintentional coupling between neighboring solder balls.
Innovation Solution
A semiconductor package design incorporating a shielding assembly with protrusions and insulating layers between solder balls to reduce crosstalk, allowing for a reduced number of ground reference voltage solder balls and enabling tighter packing, thus maintaining electrical performance while minimizing footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the pitch dimension of solder ball grid arrays is reduced to achieve miniaturization, then the footprint of semiconductor packages is reduced, but crosstalk coupling between neighboring solder balls increases resulting in electrical performance degradation
Solution Approach 1:
A shielding assembly comprising a metal layer with protrusions extending between adjacent solder balls is introduced as an intermediary structure. The protrusions create physical barriers that block electromagnetic field coupling between neighboring solder balls, thereby reducing crosstalk. This mediator allows the system to maintain reduced pitch dimensions while preserving electrical performance by preventing harmful electromagnetic interactions.
Solution Approach 2:
The shielding assembly implements local quality by providing targeted electromagnetic shielding only in regions where crosstalk occurs between adjacent solder balls. The protrusions are positioned specifically between neighboring solder balls rather than uniformly across the entire package, optimizing the shielding effect where needed most while minimizing overall structure complexity and maintaining manufacturing feasibility.
2Reliability
If a high amount of solder balls associated with ground reference voltage is employed to reduce crosstalk, then electrical performance is improved, but the footprint and device complexity increase
Solution Approach 1:
The shielding assembly acts as a physical mediator that replaces the need for excessive ground reference voltage solder balls. Instead of relying on numerous ground balls to mitigate crosstalk, the protrusions provide direct electromagnetic shielding between signal-bearing solder balls, enabling reduced ground ball count while maintaining electrical performance.
Solution Approach 2:
The invention changes the approach to crosstalk mitigation from increasing the quantity of ground reference voltage connections to introducing a structural shielding parameter. The metal layer with protrusions provides a new parameter (physical barrier density and positioning) that directly controls electromagnetic field coupling, replacing the traditional parameter of ground ball quantity.
3Length of moving object
If the pitch dimension of solder ball grid arrays is reduced, then miniaturization is achieved, but unintentional coupling between neighboring solder balls increases
Solution Approach 1:
The protrusions of the metal layer serve as intermediary barriers positioned between adjacent solder balls. These protrusions interrupt the electromagnetic field paths that would otherwise couple neighboring solder balls, providing localized shielding that enables reduced pitch dimensions without increasing crosstalk.
Solution Approach 2:
The shielding assembly segments the electromagnetic space between adjacent solder balls through the introduction of protrusions. This segmentation divides the continuous electromagnetic field into isolated regions, preventing field coupling between neighboring solder balls and enabling tighter packing while maintaining signal integrity.
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 shielding assembly effectively reduces crosstalk, allowing for a smaller footprint and improved electrical performance by enabling a higher percentage of solder balls for signal data transmission or power supply voltage, facilitating miniaturization without compromising functionality.
Implementation Method 1
Each protrusion of the plurality of protrusions is covered with an insulating layer configured to insulate each of the solder balls of the first and second plurality of solder balls
Data Source
AI summary
A semiconductor package including a package substrate including a bottom surface; a first plurality of solder balls connected to the bottom surface of the package substrate; a second plurality of solder balls connected to a motherboard; and a shielding assembly interposed between the first and the second plurality of solder balls and configured to shield each solder ball of the first and second plurality of solder balls from electromagnetic interference.