3D Inductor Using Through-Body-Vias for High Q-Factor
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Solution Overview
Problem
Conventional inductor designs in integrated circuits face challenges in achieving high inductance and quality factor due to limitations in packaging and integration with semiconductor substrates, leading to inefficiencies in high-frequency applications.
Innovation Solution
The integration of three-dimensional inductors using conductive through-body-vias that pass through the semiconductor die, allowing for multiple turns and a core structure, which can include magnetically permeable materials, to enhance inductance and reduce resistance, and the use of insulator plugs to replace semiconductor material, improving electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional planar or multilayer spiral inductor designs are used in integrated circuits, then the inductors can be integrated into the semiconductor substrate, but the inductance density and quality factor are limited due to packaging constraints and eddy current losses
Solution Approach 1:
The patent transitions from conventional planar (2D) or multilayer spiral inductor designs to a three-dimensional inductor structure using conductive through-body-vias that pass vertically through the semiconductor die. This dimensional change enables the inductor to achieve higher inductance density by utilizing the vertical dimension, while the core structure with magnetically permeable materials enhances the quality factor by concentrating magnetic flux and reducing eddy current losses in the substrate.
2Reliability
If the number of turns of the inductor is increased to increase inductance, then the inductance value increases, but the device area and resistance increase, reducing the quality factor
Solution Approach 1:
The patent employs a three-dimensional inductor configuration where conductive through-body-vias extend vertically through the semiconductor die, allowing multiple turns to be stacked in the vertical dimension rather than expanding horizontally. This enables high inductance values to be achieved within a compact footprint by utilizing the third dimension, thereby increasing inductance density without proportionally increasing the device area.
Solution Approach 2:
The inductor incorporates a core structure containing magnetically permeable materials (such as ferrite or iron) that concentrate magnetic flux and enhance the inductance per turn. This allows the inductor to achieve high inductance values with fewer turns, reducing both the device area and the total resistance, thereby improving the quality factor while maintaining high inductance.
3Reliability
If magnetically permeable materials are positioned within the inductor core to increase inductance, then the inductance increases, but eddy current losses increase, reducing the quality factor
Solution Approach 1:
The patent strategically positions magnetically permeable materials specifically within the inductor core region where magnetic flux concentration is most beneficial for increasing inductance. The through-body-via structure is designed to minimize the volume of conductive material intersecting the magnetic flux paths, thereby reducing eddy current losses while maintaining high inductance through localized magnetic permeability enhancement in the core 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 approach significantly enhances the inductance density and quality factor of inductors, enabling better performance in high-frequency applications by mitigating eddy current losses and improving the Q-factor, while maintaining or slightly reducing inductance values.
Implementation Method 1
An inductor is a conductor which is shaped in a manner which can store energy in a magnetic field adjacent to the conductor and/or partially inside the conductor
Implementation Method 2
The inductance of the inductor may often be increased by positioning magnetically permeable materials such as iron, steel, or other ferrites within the inductor core or within other areas adjacent to the conductor and within the magnetic fields so that the inductor and the magnetically permeable material are magnetically coupled to each other
Implementation Method 3
This approach significantly enhances the inductance density and quality factor of inductors, enabling better performance in high-frequency applications by mitigating eddy current losses and improving the Q-factor
Data Source
AI summary
A three-dimensional inductor is formed in an integrated circuit die using conductive through-body-vias which pass through the body of the die and contact one or more metal interconnect layers on the front side of the die and terminate on the back side of the die. In another embodiment, the through-body-vias may pass through a dielectric material disposed in a plug in the body of the die. In yet another aspect, a transformer may be formed by coupling multiple inductors formed using through-body-vias. In still another aspect, a three-dimensional inductor may include conductors formed of stacks of on chip metallization layers and conductive through-layer-vias disposed in insulation layers between metallization layers. Other embodiments are described.