Stacked Conductor Thin Film Inductor for Power Density
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Solution Overview
Problem
Developing high-quality thin film inductors for fully integrated power converters is challenging due to the need for high Q, large inductance, and high energy storage per unit area, which is essential for reducing the cost, weight, and size of electronic devices.
Innovation Solution
The design incorporates a wafer substrate with stacked conductors and magnetic yokes, including a bottom yoke, insulating layers, and a non-planar top yoke, which enhances coupling efficiency and reduces conductor resistance loss, allowing for higher current density and power density in power converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional planar inductor structures are used, then manufacturing is simpler, but inductance per unit area is limited and conductor resistance is higher
Solution Approach 1:
The patent transitions from a planar two-dimensional inductor layout to a three-dimensional stacked configuration with multiple conductor layers separated by insulating layers. This vertical stacking allows conductors to be positioned at different heights, increasing the effective inductance volume without proportionally increasing the planar footprint, thereby achieving higher inductance per unit area while maintaining reasonable manufacturing complexity
Solution Approach 2:
The inductor employs a composite structure combining multiple materials: conductive layers for current flow, magnetic core materials for flux concentration, and insulating materials to prevent electrical breakdown between stacked conductors. This composite approach enables simultaneous optimization of electrical performance, magnetic properties, and structural integrity
2Loss of energy
If conductor thickness is increased to reduce resistance, then conductor resistance loss decreases, but available space for magnetic core is reduced
Solution Approach 1:
Instead of increasing conductor thickness in the planar direction, the patent stacks multiple conductor layers vertically at different heights. This allows the total conductive cross-section to increase (reducing resistance) while the magnetic core occupies the horizontal plane, effectively decoupling the space requirements of conductors and magnetic core through three-dimensional arrangement
3Area of stationary object
If inductor area is reduced for compact design, then device size decreases, but coupling constant and Q factor may deteriorate
Solution Approach 1:
The stacked conductor configuration increases the effective coupling volume between conductors and magnetic core without increasing planar area. The vertical separation between conductor layers creates additional flux paths through the magnetic core, enhancing the coupling constant while maintaining a compact footprint
Solution Approach 2:
The patent implements a nested structure where conductors are positioned within or adjacent to the magnetic core structure in multiple layers. This nesting maximizes the interaction between conductor currents and magnetic flux within a confined volume, achieving high coupling constants without requiring large inductor area
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 configuration increases the coupling constant, reduces conductor resistance, and minimizes the required inductor area, leading to improved power converter efficiency and higher inductance per unit area, enabling more efficient and compact power conversion.
Implementation Method 1
a bottom yoke comprising a magnetic material above the wafer substrate; a non-planar top yoke above the third insulating layer, the top yoke comprising a magnetic material
Implementation Method 2
a first insulating layer above the bottom yoke; a second insulating layer above the first conductor; a third insulating layer above the second conductor
Data Source
AI summary
A thin film coupled inductor, a thin film spiral inductor, and a system that includes an electronic device and a power supply or power converter incorporating one or more such inductors. A thin film coupled inductor includes a wafer substrate; a bottom yoke comprising a magnetic material above the wafer substrate; a first insulating layer above the bottom yoke; a first conductor above the bottom yoke and separated therefrom by the first insulating layer; a second insulating layer above the first conductor; a second conductor above the second insulating layer; a third insulating layer above the second conductor; and a non-planar top yoke above the third insulating layer, the top yoke comprising a magnetic material.