Integrated Circuit EMI Shielding via Embedded Conductive Cavities
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Solution Overview
Problem
Conventional EMI shielding methods for miniaturized system-in-package (SiP) devices face challenges such as interference with thermal profiles, complex assembly processes, impracticality in high-density designs, and inability to provide hermetic enclosures due to the need for holes or removable lids in metal shield cans.
Innovation Solution
A pre-assembled circuit module with an interposer forms a Faraday Cage by using conductive cavities and vias to create an equipotential structure, allowing for EMI shielding on both sides of the circuit module substrate, enabling simplified assembly, inspection, and hermetic sealing without the need for external shield cans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If preformed metal shield cans are used for EMI shielding, then EMI shielding effectiveness is improved, but the thermal profile during solder reflow is interfered with and assembly complexity increases
Solution Approach 1:
The patent merges the EMI shielding function with the circuit board structure by integrating conductive shielding layers directly into the board layers. This eliminates the need for separate metal shield cans and their associated mechanical attachment mechanisms, thereby reducing assembly complexity while maintaining EMI shielding effectiveness.
Solution Approach 2:
The conductive shielding layers in the patent serve multiple functions: they provide EMI shielding, act as ground planes for signal references, and facilitate thermal management during solder reflow. This multi-functionality eliminates the need for separate shield cans that would only provide shielding, thereby reducing assembly complexity.
2Ease of manufacture
If metal shield cans with holes or removable lids are used, then assembly and inspection become easier, but hermetic sealing capability is lost
Solution Approach 1:
The patent merges the shielding structure with the circuit board itself, eliminating the need for separate shield cans with lids or openings. The conductive layers are integrated within the board structure, allowing hermetic sealing to be maintained while still enabling assembly and inspection through the board's own structure.
Solution Approach 2:
The patent uses thin conductive shielding layers integrated within the circuit board structure instead of rigid metal shield cans. These thin film conductive layers provide shielding while allowing the board to maintain its hermetic seal without requiring separate lids or access points.
3Object-affected harmful factors
If shield cans are placed over components during solder reflow, then EMI shielding is provided, but thermal profile control is interfered with and solder joint inspection becomes impossible
Solution Approach 1:
The patent applies the shielding function preliminarily by integrating conductive shielding layers into the circuit board structure before the soldering process. This eliminates the need to place physical shield cans over components during reflow, allowing thermal profiles to be controlled and solder joints to be inspected without compromising EMI shielding.
Solution Approach 2:
The patent merges the EMI shielding function with the circuit board structure itself, so that shielding is provided inherently during assembly rather than by separate shield cans. This integration allows thermal profiles to be maintained and solder joints to be accessible for inspection while still providing EMI shielding during the soldering process.
4Object-affected harmful factors
If multiple single cavity shield cans are used in high density designs, then EMI shielding is provided for each component, but device area and volume increase
Solution Approach 1:
The patent merges multiple shielding functions into a single integrated circuit board structure. Instead of using multiple separate shield cans for different components, the conductive shielding layers are integrated within the board itself, providing EMI shielding for multiple components simultaneously without increasing device area or volume.
Solution Approach 2:
The integrated conductive shielding layers in the circuit board serve multiple components simultaneously, providing EMI shielding across the entire board rather than requiring individual shield cans for each component. This multi-functionality reduces the total area and volume required for shielding in high-density designs.
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 reduces the area and volume required for shielded assemblies, simplifies the assembly process, allows for full cleaning and inspection, and provides effective EMI shielding while maintaining thermal conductivity and hermetic sealing.
Implementation Method 1
A pre-assembled circuit module with an interposer forms a Faraday Cage by using conductive cavities and vias to create an equipotential structure, allowing for EMI shielding on both sides of the circuit module substrate
Implementation Method 2
The walls and floor of said cavities are coated with a suitable conductive composition, e.g. plated copper, and ridges between the cavities and contact pads or conduction paths around the perimeter of the mounting surface on which the circuit module is placed make contact with corresponding contact pads or conduction paths on the circuit module, thereby creating an equipotential between the cavity walls and floor and the ground or reference plane in the circuit module
Data Source
AI summary
An integrated circuit package with a plurality of embedded electromagnetic interference (EMI) shielding and methods of making the same are disclosed. The integrated circuit packages include the use of a pre-assembled circuit module and an interposer. The circuit module has a plurality of spaced electrical component sections separated by a series of contiguous conductive spacers, and a first shielding means comprises the spacers, vias and an embedded conductive plane. In an example, the interposer has a second shielding means comprises conductive cavities, conductive ridges, vias, and a conduction pattern. In another example, the interposer further comprises conductive strips to form the second shielding means. The first shielding means overlaps the second shielding means to form a plurality of EMI shielded enclosures for holding the spaced electrical component sections therein.