Semiconductor Package Ground Opening for EMI Shielding and Clean Singulation
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Solution Overview
Problem
Conventional semiconductor device packaging processes face challenges with electromagnetic interference (EMI) shielding, as conformal coatings often result in back-side spillage, damaging the device and requiring extensive metal cutting during singulation, which shortens saw blades and causes burrs.
Innovation Solution
Incorporating solder mask openings in the package substrate to expose the ground plane at the bottom, allowing the conformal coating to contact and shield the ground plane, reducing the need for extended metal traces and preventing damage from back-side spillage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conformal coating is applied to shield the semiconductor device from electromagnetic interference, then EMI shielding is improved, but back-side spillage damages the device and requires extensive metal cutting during singulation
Solution Approach 1:
The patent extracts the ground plane from the conventional packaging structure by creating an opening in the package substrate that exposes the ground plane at the bottom surface. This allows the conformal coating to contact the ground plane without requiring extensive metal traces, thereby preventing back-side spillage damage while maintaining EMI shielding effectiveness.
Solution Approach 2:
The patent changes the dimensional arrangement of the ground plane by exposing it at the bottom surface through a vertical opening rather than extending it laterally across the package substrate. This dimensional change eliminates the need for extended metal traces that would require extensive cutting during singulation.
2Object-affected harmful factors
If ground traces and planes are extended across saw streets to provide EMI shielding, then electromagnetic shielding is improved, but the amount of metal requiring cutting during singulation increases
Solution Approach 1:
The patent removes the need for extended ground traces across saw streets by extracting the ground plane functionality to the bottom surface through an opening. This eliminates harmful metal extensions that would require extensive cutting during singulation, thereby improving productivity.
3Device complexity
If extensive metal cutting is performed during singulation to remove extended ground planes, then EMI shielding structure is adjusted, but saw blade life is shortened and burrs are generated
Solution Approach 1:
The patent extracts the ground plane to the bottom surface through an opening, eliminating the need for extensive metal cutting during singulation. This significantly prolongs saw blade life and prevents burr generation while maintaining the necessary EMI shielding structure.
Solution Approach 2:
Instead of extending ground planes laterally and cutting them during singulation, the patent inverts the approach by exposing the ground plane vertically at the bottom surface. This inversion eliminates the need for extensive cutting operations.
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 approach enhances EMI shielding, prolongs saw blade life, ensures uniform singulation cuts, and reduces assembly costs by eliminating the need for specialized cutting techniques and preventing coating damage.
Implementation Method 1
conformal coating of one or more conductive or magnetic materials can be applied over the top and sides of the microelectronic devices to provide electromagnetic shielding
Implementation Method 2
A portion of the conformal coating can fill into the opening in the second surface of the package substrate and place the conformal coating into electrical connection with the ground plane
Data Source
AI summary
Semiconductor devices with a conformal coating in contact with a ground plane at a bottom side of the semiconductor devices and associated systems and methods are disclosed herein. In one embodiment, a semiconductor device includes a semiconductor die coupled to a first surface of a package substrate. The semiconductor device can also include a molded material covering at least a portion of the package substrate and the semiconductor die. The semiconductor device can also include a ground plane in the package substrate and exposed through an opening in a second surface of the package substrate opposite the first surface. The semiconductor device can also include a conformal coating coupled to the ground plane through the opening that can shield the semiconductor device from electromagnetic interference.