EMI Shielding Layer on Semiconductor Package Surfaces
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Solution Overview
Problem
Existing EMI shielding structures in semiconductor packages are inadequate for protecting all surfaces, particularly the side and bottom surfaces, and can lead to electrical shorts with external terminals.
Innovation Solution
A method is developed to form an EMI shielding layer on all surfaces of semiconductor packages by applying a temporary protective layer around external terminals and then depositing a conductive EMI shielding layer on the top, bottom, and side surfaces, ensuring the shielding layer does not contact the terminals, using materials like silver, aluminum, or conductive polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If EMI shielding sheets are disposed inside semiconductor packages, then EMI shielding is provided, but encapsulation issues occur
Solution Approach 1:
Instead of placing EMI shielding sheets inside the encapsulant, the patent inverts the approach by forming the EMI shielding layer on the external surfaces of the encapsulant. This reversal eliminates the encapsulation issues associated with internal shielding sheets while maintaining EMI protection.
Solution Approach 2:
The patent transitions from internal three-dimensional placement of shielding sheets within the package to external two-dimensional coating on the package surfaces. This dimensional change allows comprehensive EMI shielding on all surfaces without interfering with the internal encapsulation structure.
2Object-affected harmful factors
If EMI shielding metal layers are disposed on the top surface, then EMI shielding is provided, but electrical short to external terminals may occur
Solution Approach 1:
The patent applies EMI shielding coating selectively to specific regions of the encapsulant surfaces, avoiding areas near external terminals. This localized application ensures EMI shielding effectiveness while preventing electrical short circuits between the conductive shielding layer and external terminals.
Solution Approach 2:
The encapsulant serves as an intermediary barrier between the EMI shielding layer and external terminals. The shielding layer is formed on the encapsulant surface rather than directly on terminals, using the encapsulant material as a mediating layer that provides both EMI shielding and electrical isolation.
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 method enhances EMI shielding across all surfaces of semiconductor packages while preventing electrical shorts and improving the adhesion of the shielding layer, offering better EMI protection than conventional methods.
Implementation Method 1
the temporary protective layer is removed by heating after forming the EMI shielding layer
Implementation Method 2
an EMI shielding layer is formed on the top surface, the bottom surface, and those side surfaces of the semiconductor package without disposed on the exposed surfaces of the external terminals
Data Source
AI summary
Disclosed is a method for forming an EMI shielding layer on all surfaces of a semiconductor package in order to enhance EMI shielding effect on all surfaces and to prevent electrical short to external terminals of the semiconductor package. According to the method, a temporary protective layer is formed on the external terminals where the temporary protective layer is further in contact with a plurality of annular surface regions of the semiconductor package surrounding and adjacent to the external terminals. Then, the EMI shielding layer is formed on the top surface, the bottom surface and the side surfaces of the semiconductor package without forming on the external terminals.