Permalloy Core Inductor Package With Layered Core for Higher Inductance
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Solution Overview
Problem
The semiconductor industry faces challenges in integrating inductors with high magnetic permeability into compact semiconductor packages due to limitations in existing packaging techniques, which affect inductance and manufacturing costs.
Innovation Solution
The method involves forming an integrated circuit package with a magnetic permalloy core comprising vertically stacked alternating permalloy and epoxy layers, allowing for increased magnetic permeability and higher inductance, and integrating these cores into existing processes for efficient and compact power inductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional packaging techniques are used to integrate inductors, then manufacturing simplicity is maintained, but inductance and magnetic permeability are insufficient
Solution Approach 1:
The permalloy core is divided into multiple thin layers (first permalloy layer, second permalloy layer, etc.) separated by dielectric layers. This segmentation allows each layer to contribute to the magnetic field while reducing eddy current losses, thereby increasing effective inductance without requiring a single large complex structure
Solution Approach 2:
The inductor structure is nested within the semiconductor package, with the permalloy core layers positioned between the substrate and the semiconductor die. The dielectric layers are nested between the permalloy layers, creating a compact nested arrangement that integrates the inductor function within the existing package footprint without increasing overall device volume
2Adaptability or versatility
If inductor integration is implemented in existing semiconductor packages, then functionality is improved, but manufacturing cost increases
Solution Approach 1:
The permalloy core layers and dielectric layers are formed and patterned before the semiconductor die is attached to the substrate. This preliminary formation allows the inductor structure to be prepared in advance, enabling subsequent die attachment and wire bonding to proceed using existing manufacturing processes without requiring costly retooling or additional processing steps
Solution Approach 2:
The patent uses standard permalloy material properties and conventional dielectric materials with known permittivity values, allowing the design to be implemented using existing material inventories and processing parameters. This approach avoids the need for specialized or proprietary materials that would increase manufacturing costs
3Area of stationary object
If compact inductor design is used, then space utilization is improved, but magnetic permeability decreases
Solution Approach 1:
The inductor structure uses a composite arrangement of multiple permalloy layers separated by dielectric layers. This composite structure maintains high effective magnetic permeability because each permalloy layer contributes to the magnetic flux while the thin dielectric spacers prevent short-circuiting of the magnetic field, achieving both compactness and high permeability
Solution Approach 2:
Instead of increasing the planar area of a single permalloy layer to improve inductance, the patent extends the magnetic path in the vertical dimension by stacking multiple permalloy layers. This dimensional transition allows the inductor to achieve higher inductance and effective permeability within a compact footprint by utilizing the third dimension
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 results in improved inductor performance with lower manufacturing costs and reduced spacing needs, enabling more efficient and compact power inductors that can be easily integrated into existing semiconductor packages.
Implementation Method 1
The permalloy core may include a plurality of vertically stacked alternating layers that include a plurality of permalloy layers and a plurality of epoxy layers... increased magnetic permeability of the permalloy core, which results in a higher inductance
Data Source
AI summary
A package includes a first redistribution structure, a die disposed over the first redistribution structure, a molding material surrounding the die, a second redistribution structure over the die and the molding material, and an inductor includes a permalloy core. The permalloy core is embedded in the molding material, and the permalloy core includes vertically stacked alternating layers. The vertically stacked alternating layers includes epoxy layers, and permalloy layers, where each of the permalloy layers is disposed between two epoxy layers of the epoxy layers.