Camera Module EMI Shielding via Metal Plate and Coating
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Solution Overview
Problem
Conventional camera modules lack effective electromagnetic interference (EMI) shielding, which is crucial for high-frequency applications like RF products.
Innovation Solution
A camera module design incorporating a metal plate with a metal coating layer and a first light shielding layer, where the metal plate extends over the image sensor device chip and surrounds the optical lens, providing EMI shielding while also serving as a mechanical supporter and ground pin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional lamination and dicing process is used to fabricate camera module, then manufacturing simplicity is maintained, but electromagnetic interference shielding capability is insufficient
Solution Approach 1:
The fabrication process is segmented into distinct stages: substrate preparation with metal plate, wafer-level packaging of image sensor, lens array assembly, and post-dicing EMI shielding application. This segmentation allows each stage to be optimized independently, incorporating EMI shielding measures at multiple points without overwhelming complexity at any single stage.
Solution Approach 2:
EMI shielding measures are taken preliminarily by integrating a metal plate into the substrate before mounting the image sensor wafer. This preliminary action establishes the base EMI shielding structure early in the fabrication process, preventing interference from propagating through subsequent assembly steps.
2Object-affected harmful factors
If metal plate extends over image sensor chip to provide EMI shielding, then electromagnetic interference protection is improved, but light leakage risk increases
Solution Approach 1:
The metal plate is designed with spatially varying properties: it extends beyond the image sensor chip boundaries to provide EMI shielding, but precise apertures are created at locations corresponding to the lens array to allow light transmission. This local differentiation of quality (shielding vs. transparency) resolves the contradiction between EMI protection and light transmission.
Solution Approach 2:
Aperture masks or alignment structures serve as intermediaries during the fabrication process to define the light transmission paths through the metal plate. These intermediaries ensure that the apertures are precisely positioned to match the lens array, mediating between the conflicting requirements of EMI shielding and optical access.
3Productivity
If wafer level packaging process is used, then manufacturing efficiency is improved, but EMI shielding integration becomes more challenging
Solution Approach 1:
The EMI shielding function is merged with the substrate structure by integrating the metal plate into the PCB substrate during its fabrication process. This merging eliminates the need for separate EMI shielding components and simplifies the overall assembly, maintaining compatibility with wafer-level packaging efficiency.
Solution Approach 2:
The metal plate serves multiple functions simultaneously: it provides mechanical support for the image sensor wafer, acts as an EMI shielding barrier, and serves as a mounting structure for the lens array. This multi-functionality reduces the total component count and simplifies the fabrication process while maintaining high manufacturing efficiency.
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 solution effectively shields the camera module from electromagnetic interference, enhancing its mechanical strength and enabling reliable operation in high-frequency applications by connecting the metal plate to ground pads on a printed circuit board.
Implementation Method 1
A metal coating layer surrounds vertical surfaces of the optical lens and a top surface of the part of the metal plate
Implementation Method 2
A first light shielding layer covers vertical surfaces of the metal coating layer
Data Source
AI summary
The invention provides a camera module and a method for fabricating the same. A camera module includes an image sensor device chip having a plurality of solder balls on a bottom surface thereof. An optical lens is disposed on the image sensor device chip. A metal plate has a part that extending over the bottom surface of the image sensor device. A metal coating layer surrounds vertical surfaces of the optical lens and a top surface of the part of the metal plate. A first light shielding layer covers vertical surfaces of the metal coating layer.