Embedded Spiral Inductor Package With Discrete EMI Shielding
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Solution Overview
Problem
Conventional inductive elements in RF modules face challenges such as electromagnetic interference, poor magnetic shielding, limited miniaturization, high energy consumption, and difficulties in mass production due to poor processability and geometric accuracy, along with limitations in magnetic permeability and uniformity when using magnetic powder in insulating materials.
Innovation Solution
The electronic package design features a substrate with layered spiral inductor circuits, shielding layers without electrical connection, and fan-out conductive copper pillars, using materials like Ajinomoto build-up film or molded epoxy resin, with magnetic or non-magnetic metal shielding layers arranged in specific patterns to enhance magnetic shielding and inductance value without relying on magnetic powder mixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic powder is mixed in the insulating material to improve magnetic shielding and inductance value, then magnetic shielding capability is enhanced, but the magnetic permeability becomes relatively low and uniformity is poor
Solution Approach 1:
The patent divides the magnetic shielding function into separate discrete shielding layers rather than mixing magnetic powder throughout the insulating material. These shielding layers are positioned at specific locations (between spiral inductor circuits and on the surface of the package substrate) to provide targeted magnetic shielding where needed, achieving both improved shielding capability and uniform magnetic permeability in the insulating material itself.
Solution Approach 2:
The patent introduces a dedicated magnetic shielding layer as an intermediary component between the spiral inductor circuits and the external environment. This shielding layer, made of magnetic material, acts as a mediator to redirect and contain magnetic field lines, providing effective magnetic shielding without requiring the insulating material to have mixed magnetic powder, thus maintaining the material's uniformity and electrical properties.
2Volume of moving object
If spiral inductive elements are placed closer to reduce distance between elements for miniaturization, then device size is reduced, but electromagnetic interference between elements increases
Solution Approach 1:
The patent extracts the magnetic shielding function from the insulating material structure and implements it as separate shielding layers positioned strategically between the spiral inductor circuits. This allows the inductor elements to be placed closer together for miniaturization while the shielding layers actively contain and redirect magnetic field lines, preventing electromagnetic interference between adjacent elements.
Solution Approach 2:
The patent applies preliminary anti-action by placing magnetic shielding layers in advance between the spiral inductor circuits before the electromagnetic interference can occur. These shielding layers pre-establish magnetic field containment paths that redirect and contain magnetic flux, preventing it from interfering with adjacent inductor elements and thus proactively eliminating electromagnetic interference issues.
3Ease of manufacture
If conventional fabrication processes like injection molding or transfer molding are used for coil elements, then manufacturing is simplified, but processability is poor and mass production with large boards is not feasible
Solution Approach 1:
The patent replaces conventional mechanical fabrication processes (injection molding, transfer molding, low temperature co-firing) with a PCB-based build-up circuit board fabrication process. This process uses standard PCB manufacturing techniques including copper foil lamination, photolithography, and etching to create the spiral inductor circuits directly on the package substrate, enabling mass production on large boards with high precision and good processability.
4Reliability
If magnetic powder is mixed in the insulating material, then magnetic shielding is provided, but the material properties are not suitable for circuit patterning process
Solution Approach 1:
The patent segments the magnetic shielding function from the insulating material and implements it as separate magnetic shielding layers. This allows the insulating material to maintain its pure electrical properties and be suitable for circuit patterning processes, while the dedicated magnetic shielding layers provide the required magnetic shielding capability without interfering with the insulating material's electrical characteristics or patterning processes.
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 design effectively reduces electromagnetic interference, improves inductance value and quality factor, supports high current loads, and enables mass production with improved geometric accuracy and reduced production costs, addressing the limitations of conventional inductive elements.
Implementation Method 1
a plurality of shielding layers oppositely embedded in the first side and the second side of the insulator to shield the spiral inductor circuits without being electrically connected to the spiral inductor circuits
Data Source
AI summary
An electronic package is provided and includes an electronic element connected to a plurality of inductor circuits embedded in an insulator of a package substrate by fan-out conductive copper pillars, and at least one shielding layer non-electrically connected to the inductor circuits, where the shielding layer includes a plurality of line segments not connected to each other, such that the shielding layer shields the inductor circuits, thereby achieving the electrical requirements of high-current products while improving the inductance value and quality factor.