3D Integrated Inductor With Magnetic Layers for High Inductance Density
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Solution Overview
Problem
The challenge in miniaturizing passive inductive elements for integrated circuits is that they often require high current and high inductance while maintaining a small form factor, which is difficult due to the relationship between inductance and physical dimensions, leading to complexity and cost in fabrication.
Innovation Solution
An integrated inductor device is designed with a 3D solenoid configuration and multiple magnetic layers within an aperture, using conductive pillars and redistribution layers to enhance inductance while reducing fabrication complexity and cost, utilizing wafer-level processing techniques such as sputter deposition and photoresist-defined electroplating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If traditional planar inductor structures are used, then fabrication is simpler, but inductance per unit area is lower
Solution Approach 1:
The patent transitions from a planar 2D inductor structure to a 3D structure by adding vertical magnetic layers above and below the conductive lines. This dimensional change allows the magnetic flux to be confined and enhanced in the vertical direction, achieving higher inductance density within the same footprint area.
Solution Approach 2:
The patent uses composite structures combining conductive materials (copper or aluminum lines) with magnetic materials (ferromagnetic layers) in a multi-layer configuration. This composite approach creates synergistic effects where the magnetic layers enhance the inductance of the conductive paths, achieving superior performance compared to either material alone.
2Area of moving object
If inductor size is reduced for miniaturization, then integration density improves, but achieving high current and high inductance becomes difficult
Solution Approach 1:
By stacking magnetic layers vertically above and below the conductive lines, the patent creates a 3D inductor structure that achieves high inductance and current capacity in a reduced planar footprint. The vertical stacking allows more magnetic material to be packed into the same area, enhancing both inductance and current handling capability.
Solution Approach 2:
The patent changes the geometric parameters of the inductor by introducing vertical spacing between magnetic layers and optimizing the thickness of each layer. This parameter optimization allows the inductor to achieve high inductance and current capacity while maintaining a compact footprint suitable for integrated circuits.
3Reliability
If more magnetic material is added to increase inductance, then inductance value improves, but fabrication complexity and cost increase
Solution Approach 1:
The patent divides the magnetic material into discrete segments or layers that are positioned at specific locations above and below the conductive lines. This segmentation allows for optimized placement of magnetic material where it is most effective, reducing the total amount of magnetic material needed while achieving the desired inductance value.
Solution Approach 2:
The magnetic layers serve multiple functions: they enhance inductance, provide magnetic flux confinement, and can be integrated with standard semiconductor fabrication processes. This multi-functionality reduces the need for additional specialized components or processes, thereby reducing overall fabrication complexity despite the added inductance enhancement.
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 achieves higher inductance within a smaller footprint compared to traditional methods, with reduced fabrication time and complexity, and improved reliability, making it suitable for applications like power management integrated circuits.
Implementation Method 1
one or more magnetic layers extending along a length of the integrated inductor and within an aperture of the integrated inductor
Implementation Method 2
conductive pillars connecting the first set of conductive lines to the second set of conductive lines to form an integrated inductor
Data Source
AI summary
An inductive device includes a first set of conductive lines, a second set of conductive lines, and conductive pillars connecting the first set of conductive lines to the second set of conductive lines to form an integrated inductor. The inductive device also includes one or more magnetic layers extending along a length of the integrated inductor and within an aperture of the integrated inductor.