Partial Shielding Structure for Electronic Assemblies Without Laser Ablation
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Solution Overview
Problem
Conventional methods for forming partial shielding in electronic assemblies, such as laser ablation, are complex and result in low yield and high costs, often causing undesired damage to electronic components.
Innovation Solution
A method involving the use of a mask to cover electronic components, forming an encapsulant layer, creating a trench, applying a shielding layer, and detaching the mask to achieve a partial shielding configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser ablation process is used to remove solid materials at intended locations of conformal shielding, then partial shielding can be obtained, but the process becomes complicated and yield is reduced
Solution Approach 1:
The patent applies preliminary action by pre-defining the shielding pattern through a mask layer that is formed before the conformal shielding coating is applied. The mask layer with patterned openings is disposed on the substrate, then the conformal shielding is coated over it, creating the partial shielding structure in advance rather than removing material later. This prevents damage to electronic components and improves yield.
2Object-affected harmful factors
If laser ablation process is used to form partial shielding, then shielding can be achieved, but electronic components may be damaged
Solution Approach 1:
The mask layer is prepared in advance with patterned openings at the locations where shielding is not desired. The conformal shielding material is then coated over the mask layer, so the shielding is formed positively by deposition rather than negatively by removal. This preliminary configuration of the mask layer ensures that electronic components are never exposed to laser energy that could damage them.
Solution Approach 2:
The patent replaces the laser ablation process (optical/thermal system) with a deposition process using a mask layer (mechanical/physical system). Instead of using laser energy to remove material, the invention uses a physical mask structure to guide the deposition of shielding material, thereby protecting electronic components from thermal and optical damage while still achieving the desired partial shielding effect.
3Object-affected harmful factors
If conformal shielding is coated over entire semiconductor device, then EMI protection is improved, but transceiver module functionality is blocked
Solution Approach 1:
The patent applies local quality by creating a non-uniform shielding structure where different regions of the device have different shielding properties. The mask layer has patterned openings at specific locations (such as over the transceiver module) while maintaining shielding in other regions. This allows the conformal shielding to provide EMI protection locally where needed while leaving transceiver functionality intact at designated areas.
Data Source
AI summary
Provided is a method for forming a partial shielding for an electronic assembly, comprising: providing an electronic assembly mounted on a mother board, wherein the electronic assembly comprises a substrate, and at least one electronic component and a conductive pattern mounted on a top surface of the substrate; disposing a mask onto the substrate to cover the at least one electronic component; forming an encapsulant layer on the mother board to encapsulate at least the electronic assembly; forming a trench through the encapsulant layer to expose at least a portion of the conductive pattern and at least a portion of lateral surfaces of the mask; forming a shielding layer on the mother board to cover the encapsulant layer and fill in the trench; and detaching the mask from the mother board.