EMI Shielding Layer with Substrate Test Pads for Semiconductor Packages
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Solution Overview
Problem
Current semiconductor packages lack effective EMI shielding solutions that also enable efficient testing of electrical connections without damaging the shielding layers, which is crucial for ensuring proper electromagnetic interference suppression and device performance.
Innovation Solution
Incorporating an EMI shielding layer that surrounds the chip, a ground pad, and a test pad spaced apart from the ground pad on the substrate, forming a loop circuit to detect resistance values and determine electrical connection states without direct contact with the shielding layer, allowing for non-invasive testing of the EMI shielding layer's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an EMI shielding layer is added to suppress electromagnetic interference, then EMI suppression performance is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The EMI shielding layer is designed to serve multiple functions: it provides electromagnetic interference suppression while also acting as an electrical connection element that can be tested through the substrate. The shielding layer is electrically connected to ground pads on the substrate, allowing it to function both as an EMI barrier and as part of the electrical testing infrastructure, thereby reducing overall device complexity.
Solution Approach 2:
The substrate serves as an intermediary between the EMI shielding layer and the testing apparatus. Instead of requiring direct access to the shielding layer for testing, the substrate provides ground pads and test pads that mediate the electrical connection, allowing non-invasive testing of the shielding layer's electrical properties while maintaining its EMI suppression function.
2Measurement precision
If testing methods directly contact the EMI shielding layer, then measurement precision is improved, but the shielding layer may be damaged
Solution Approach 1:
The substrate with its ground pads and test pads acts as an intermediary that enables indirect testing of the EMI shielding layer. By measuring electrical properties through the substrate's pads rather than directly contacting the shielding layer, the testing method achieves sufficient measurement precision while preventing mechanical damage to the fragile shielding layer structure.
Solution Approach 2:
The testing function is segmented from the EMI shielding layer itself. The substrate provides separate ground pads and test pads that are electrically connected to the shielding layer but physically distinct from it. This segmentation allows testing operations to be performed on the pads without directly impacting the shielding layer, thus maintaining measurement precision while protecting the shielding layer's integrity.
3Ease of operation
If more testing pads are added to the substrate, then ease of operation for testing is improved, but device complexity increases
Solution Approach 1:
The ground pads and test pads on the substrate are designed to serve multiple purposes: they provide electrical grounding for the EMI shielding layer, enable electrical connection testing, and facilitate manufacturing processes. This multi-functionality reduces the need for additional dedicated testing structures, thereby improving ease of operation without proportionally increasing device complexity.
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 configuration effectively suppresses electromagnetic interference while enabling reliable testing of electrical connections, preventing damage to the EMI shielding layer and ensuring normal operation of semiconductor packages.
Implementation Method 1
an electromagnetic interference (EMI) shielding layer disposed on the substrate such that the EMI shielding layer surrounds the chip
Implementation Method 2
detecting a resistance value of the loop circuit, and determining an electrical connection state of the loop circuit according to the detecting resistance value of the loop circuit
Data Source
AI summary
A semiconductor package includes a substrate, a chip disposed over a top surface of the substrate, an electromagnetic interference (EMI) shielding layer disposed over the substrate such that the EMI shielding layer surrounds the chip, a ground pad disposed in the substrate to contact a bottom surface of the substrate, and a test pad disposed in the substrate to contact the bottom surface of the substrate and spaced apart from the ground pad. A method of testing the semiconductor package is performed using a loop circuit to which a current is applied, the loop circuit being formed by electrically coupling the ground pad, the EMI shielding layer, and the test pad.