Through-Mold EMI Shielding Structure for Multi-Die RF Modules
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Solution Overview
Problem
Current 5G and WiFi6 radio frequency frontend modules experience noise-to-signal coupling between RFIC chips due to the lack of internal electromagnetic interference (EMI) shielding, which worsens in compact modules requiring stringent EMI shielding for new radio bands and increased thermal management.
Innovation Solution
Implementing a through-mold contact (TMC) enabled double EMI shielding structure with sidewall shields and thermally conductive mold compounds to reduce interference and enhance thermal performance in multi-die modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If RFIC chips are placed side-by-side and flip-chip bonded onto a laminate substrate without internal EMI shielding, then device complexity is reduced and ease of manufacture is improved, but electromagnetic interference between chips causes noise-to-signal coupling that degrades signal integrity
Solution Approach 1:
The patent divides the module into separate encapsulated die regions with through-mold trenches between them, creating physical and electromagnetic segmentation that reduces noise coupling while maintaining a compact integrated structure
Solution Approach 2:
The patent introduces an intermediate shield structure formed within the through-mold trench between adjacent die, acting as an electromagnetic barrier that blocks noise propagation while allowing the chips to remain in close proximity for compact packaging
2Productivity
If compact module size is implemented, then productivity and integration density are improved, but electromagnetic interference shielding becomes more stringent and difficult to achieve
Solution Approach 1:
The patent moves the shield structure from a planar layout to a vertical through-mold configuration, utilizing the depth dimension of the mold compound to create EMI shielding that does not consume additional lateral space, thereby maintaining compact module footprint while providing effective electromagnetic isolation
Solution Approach 2:
The patent nests the shield structure within the existing through-mold trench and mold compound structure, integrating EMI shielding functionality into the packaging architecture without adding external shielding components that would increase module size
3Object-affected harmful factors
If through-mold contact structure with shields is implemented, then EMI shielding effectiveness is improved, but device complexity and manufacturing steps increase
Solution Approach 1:
The patent combines the through-mold contact structure with the EMI shield formation process, where the same trench that provides electrical contact also houses the shield structure, merging two functions into a single integrated feature rather than requiring separate structures
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 TMC structure significantly reduces interference and enhances thermal performance by providing comprehensive EMI shielding and heat conduction, addressing the noise coupling issues in compact RF frontend modules.
Implementation Method 1
The die MC part may encapsulate sidewalls and an upper surface of the die
Implementation Method 2
A first shield, which may comprise a surround shield portion formed in the through-mold trench on a sidewall and on an upper surface of the die MC part. The first shield may be formed of metal
Implementation Method 3
Implementing a through-mold contact (TMC) enabled double EMI shielding structure with sidewall shields and thermally conductive mold compounds to reduce interference and enhance thermal performance
Data Source
AI summary
Disclosed are examples of multi-die modules that includes a die (e.g., a power amplifier) and an adjacent die placed side-by-side and bonded onto a substrate with a mold compound. The die (e.g., a switch or a low noise amplifier) may be double EMI shielded to minimize or even eliminate EMI/noise coupling with the adjacent die (e.g., switch, low noise amplifier, etc.). Another mold compound, which can be thermally conductive, may be provided to improve transfer of heat away from the die and/or the adjacent die.