Micro Inductor With Magnetic Core For Compact IC Design
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Solution Overview
Problem
Inductors and transformers in integrated circuits occupy significant area, leading to circuit instability and noise issues, and are not suitable for high-frequency applications due to their large size and parasitic effects.
Innovation Solution
Incorporating a magnetic core into micro inductors and micro transformers to reduce their size while maintaining equivalent inductance, resulting in lower series resistance and higher Q factors, enabling operation at higher frequencies with lower power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spiral air core inductors and transformers are used, then they can be fabricated using conventional integrated circuit manufacturing techniques, but they take up a disproportionately large share of the available area
Solution Approach 1:
The patent embeds the inductor or transformer coils within a three-dimensional cavity structure formed in the substrate. This nesting approach allows the magnetic path to be contained within the substrate volume rather than requiring large planar area, effectively hiding the magnetic flux path inside the substrate like a nested doll.
Solution Approach 2:
The patent transitions from two-dimensional planar spiral structures to three-dimensional vertical structures by forming cavities and coils in multiple layers within the substrate. This dimensional change allows the magnetic path to extend through the substrate thickness, reducing the planar footprint significantly.
2Area of stationary object
If spiral air core inductors and transformers are miniaturized, then they can be used in compact communication systems, but they have an open magnetic field which generates interference and undesirable magnetic coupling
Solution Approach 1:
The patent extracts the magnetic flux path from the open air-core environment and confines it within a closed magnetic circuit formed by high-permeability material walls lining the cavity. This extraction and confinement of the magnetic field prevents it from radiating outward and causing interference with surrounding circuits.
Solution Approach 2:
The patent introduces high-permeability magnetic material walls as an intermediary between the coil and the external environment. These walls act as a magnetic shield that guides and contains the magnetic flux within the cavity, preventing unwanted magnetic coupling with adjacent circuits while allowing the compact structure to function properly.
3Ease of manufacture
If spiral air core inductors are made large, then they can be fabricated with conventional techniques, but their large size presents large resistance and large parasitic capacitance resulting in lower self-resonate frequency
Solution Approach 1:
The patent moves the magnetic path from a two-dimensional planar spiral to a three-dimensional vertical cavity structure. This allows the inductance to be achieved through vertical flux paths through the substrate thickness rather than large horizontal loops, significantly reducing the effective area and thus the parasitic capacitance while maintaining manufacturability.
Solution Approach 2:
The patent changes the geometric parameters of the inductor structure by forming deep cavities and using multi-layer coil configurations. This changes the inductance-to-area ratio and reduces the parasitic capacitance by minimizing the overlapping conductor areas, thereby increasing the self-resonate frequency while still using conventional fabrication techniques.
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
The use of a magnetic core allows for the creation of compact micro inductors and micro transformers with increased inductance, reducing area requirements and improving performance by lowering resistance and enabling higher frequency operation.
Implementation Method 1
An integrated circuit is formed with a micro inductor with a magnetic core. An integrated circuit is formed with a micro transformer with a magnetic core.
Implementation Method 2
Incorporating a magnetic core into micro inductors and micro transformers to reduce their size while maintaining equivalent inductance
Data Source
AI summary
An integrated circuit with a micro inductor or with a micro transformer with a magnetic core. A process of forming an integrated circuit with a micro inductor with a magnetic core. A process of forming an integrated circuit with a micro transformer with a magnetic core.