Magnetic Bilayer Structure for Semiconductor Package Inductance
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Solution Overview
Problem
Current semiconductor packages face challenges with discrete inductors due to high costs, complex embedding processes, increased thickness, space requirements, and limitations in high-density microelectronic devices, while air core inductors have lower magnetic permeability and inefficiencies, and integrating magnetic materials into these packages is difficult and costly.
Innovation Solution
The development of cored or coreless semiconductor packages with magnetic bilayer structures, comprising a magnetic layer and a dielectric layer, which are isolated from bath chemistries and tools, allowing for flexible material choices and simplified manufacturing without the need for specialized equipment, reducing costs and enhancing electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete inductors with magnetic cores are used, then inductance is increased, but cost increases and embedding process complexity increases
Solution Approach 1:
The patent divides the inductor structure into multiple thin film layers deposited sequentially on the package substrate. Each layer contributes to the overall inductance through its geometric configuration and magnetic properties, allowing the inductor to be integrated directly into the substrate without complex embedding processes.
Solution Approach 2:
The patent combines the inductor formation process with the existing package substrate fabrication process. The magnetic bilayer structure is deposited and patterned as part of the substrate manufacturing sequence, merging what would otherwise be separate discrete component assembly steps into a unified fabrication process.
2Reliability
If discrete inductors are embedded or surface mounted, then inductance is provided, but package thickness increases
Solution Approach 1:
The patent transitions from three-dimensional discrete inductor components to two-dimensional thin film patterns deposited on the substrate surface. By using planar spiral and interdigitated geometries, the inductor occupies lateral space rather than adding vertical thickness, enabling high-density integration in thin packages.
3Ease of manufacture
If air core inductors are used, then manufacturing is simplified, but magnetic permeability and inductance efficiency decrease
Solution Approach 1:
The patent employs a composite magnetic bilayer structure where a high-permeability magnetic material layer is combined with a soft magnetic composite layer. This composite approach achieves high effective permeability and inductance efficiency while maintaining compatibility with standard thin film deposition and patterning manufacturing processes.
4Reliability
If magnetic materials are integrated into semiconductor packages, then inductance efficiency is improved, but manufacturing difficulty and cost increase
Solution Approach 1:
The patent replaces mechanical embedding and assembly processes with physical vapor deposition and chemical vapor deposition techniques. These thin film deposition methods allow magnetic materials to be deposited conformally and precisely patterned using standard photolithography, eliminating the need for complex mechanical handling and assembly of magnetic components.
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 minimizes the drawbacks of discrete and air core inductors by providing chemically resilient, cost-effective, and high-density semiconductor packages with improved electrical performance and reduced thickness.
Implementation Method 1
A magnetic core can increase the inductance of a coil by increasing the magnetic field. This increase is due to the magnetic core's higher magnetic permeability
Implementation Method 2
a magnetic bilayer structure comprising a magnetic layer and a dielectric layer
Data Source
AI summary
Techniques for fabricating a cored or coreless semiconductor package having one or more magnetic bilayer structures embedded therein are described. A magnetic bilayer structure includes a magnetic layer and a dielectric layer. For one technique, fabricating a cored or coreless semiconductor package includes: depositing a seed layer on a build-up layer; forming a raised pad structure and a trace on the seed layer; removing one or more uncovered portions of the seed layer to uncover top surfaces of one or more portions of the build-up layer; applying a magnetic bilayer structure on the raised pad structure, the trace, any unremoved portion of the seed layer, and the top surfaces of the one or more portions of the build-up layer, the magnetic bilayer structure comprises a magnetic layer and a dielectric layer; and forming a conductive structure on the raised pad structure. Other techniques are also described.