SiP Metallization via Vertical Walls for EMI Shielding
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Solution Overview
Problem
Existing system-in-package (SiP) modules face challenges in integrating effective electromagnetic interference (EMI) shielding due to difficulties in ensuring electrical connection between the metal shield and the ground ring, particularly as substrates thin, leading to incomplete EMI shielding.
Innovation Solution
The implementation of metallization along vertical walls in the end portions of the substrate, formed through common substrates after singulation, provides a larger contact area for coupling the metal shield to the ground ring, ensuring electrical connection and forming a complete EMI shield by coupling the metal shield to the ground layer in the printed circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal shield is formed over the SiP encapsulant, then EMI shielding is provided, but electrical connection between the shield and ground ring cannot be ensured due to substrate thinning
Solution Approach 1:
The patent transitions from a two-dimensional ground ring on the substrate surface to a three-dimensional via structure that extends vertically through the substrate. This via structure creates additional contact area between the metal shield and ground potential, ensuring reliable electrical connection even as substrate thickness decreases.
Solution Approach 2:
The ground vias are formed and filled with conductive material before the metal shield is applied to the encapsulant. This preliminary preparation ensures that when the shield is later connected to ground, the electrical pathway is already established and reliable, preventing connection failures.
2Length of moving object
If substrate thickness is reduced to enable thinner SiP modules, then device size is reduced, but contact area between metal shield and ground ring decreases
Solution Approach 1:
The patent compensates for reduced substrate thickness by adding a vertical dimension through via structures. Instead of relying solely on horizontal contact area, the solution creates vertical conductive pathways that extend through the thinned substrate, maintaining adequate contact area despite reduced thickness.
Solution Approach 2:
The via structure is nested within the substrate, with the conductive fill material positioned inside the via cavity. This nested configuration maximizes the use of available space within the thinned substrate while providing sufficient electrical contact area between the shield and ground.
3Object-affected harmful factors
If conventional EMI shielding processes are used, then shielding is provided, but the process is complex and yield is reduced due to connection failures
Solution Approach 1:
The ground vias are prepared in advance before shield application, ensuring that the electrical connection pathway is established beforehand. This preliminary action prevents connection failures during assembly and reduces manufacturing complexity, thereby improving yield.
Solution Approach 2:
The via structure acts as an intermediary element between the metal shield and the ground ring. This intermediate conductive structure simplifies the connection process by providing a dedicated, reliable pathway for electrical grounding, reducing process complexity and improving manufacturing yield.
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 the reliability of EMI shielding by ensuring a robust electrical connection between the metal shield and the ground layer, reducing the likelihood of gaps and increasing the yield of functional SiP modules while reducing costs.
Implementation Method 1
EMI shielding for SiPs may be difficult and process intensive to integrate into the SiP structure
Implementation Method 2
The metallization along the vertical walls in the end portions of the substrate may be via metallization from through-metal vias formed through a common substrate
Data Source
AI summary
A system in package (SiP) is disclosed that uses an EMI shield to inhibit EMI or other electrical interference on the components within the SiP. A metal shield may be formed over the SiP. The metal shield may be electrically coupled to a ground layer in a printed circuit board (PCB) to form the EMI shield around the SiP. The substrate of the SiP may include at least some metallization along vertical walls in the end portions of the substrate. The metallization may provide a large contact area for coupling the metal shield to a ground ring coupled to the ground layer in the PCB. The metallization along the vertical walls in the end portions of the substrate may be formed as through-metal vias in a common substrate before singulation to form the SiP.