Recessed Inductor Structure Reducing Step Height
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Solution Overview
Problem
The challenge lies in fabricating integrated circuit (IC) specific inductors with variable inductance that can precisely fit the needs of customers, as pre-designed inductors with fixed inductance values often result in suboptimal performance due to mismatched inductance requirements, leading to increased resistance and fabrication complexities such as delamination and difficulty in controlling the thickness and shape of dielectric structures.
Innovation Solution
The IC inductor is embedded in a dielectric structure with conductive wires and magnetic layers positioned within a trench of the dielectric layer, allowing for precise control of the inductor's shape and size, reducing the step height to less than 15 micrometers, which mitigates delamination issues and simplifies the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pre-designed inductors with fixed inductance values are used, then fabrication is simpler, but performance is suboptimal due to mismatched inductance requirements
Solution Approach 1:
The patent implements variable inductance by making the inductor structure adjustable after fabrication. The conductive wires can be reconfigured between series and parallel connections, and the magnetic layer coverage can be modified, allowing the inductance value to be dynamically changed to match specific customer requirements while maintaining fabrication simplicity
Solution Approach 2:
The patent changes physical parameters of the inductor structure, specifically the configuration of conductive wires (series/parallel) and the coverage area of magnetic layers, to achieve variable inductance values. This allows a single fabricated structure to provide multiple inductance options without requiring separate fabrication processes for each value
2Reliability
If variable inductance inductors are fabricated with precise control, then performance matches customer needs, but fabrication complexity increases
Solution Approach 1:
The patent divides the inductor into modular segments: separate conductive wire segments that can be independently connected in series or parallel, and discrete magnetic layer regions that can be selectively formed or removed. This segmentation allows variable inductance to be achieved through simple reconfiguration rather than complex continuous adjustment
Solution Approach 2:
The patent designs a universal inductor structure that can serve multiple inductance values through reconfiguration. The same physical structure with its conductive wires and magnetic layers can be arranged to provide different inductance values, making a single fabrication process serve multiple functions and reducing overall complexity
3Manufacturing precision
If dielectric structures are formed with precise thickness control, then inductor performance is optimized, but delamination issues occur
Solution Approach 1:
The patent applies different dielectric layer configurations in different regions of the inductor structure. Thicker dielectric layers are placed in areas where precise thickness control is critical for inductance performance, while thinner or absent dielectric layers are used in areas where delamination risk is the primary concern, optimizing both precision and reliability locally
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 enhances the structural integrity, reliability, and ease of design for the inductor structure, reducing fabrication time, complexity, and costs while ensuring optimal performance by allowing for precise control over the inductor's dimensions and reducing the risk of delamination.
Implementation Method 1
An inductor is a passive element that stores electrical energy in a magnetic field when electric current flows through the inductor
Implementation Method 2
a first magnetic layer disposed within the trench and conformally extending along the opposing sidewalls; a second magnetic layer overlying the first magnetic layer and the conductive wires
Data Source
AI summary
Various embodiments of the present disclosure are directed towards an integrated circuit (IC) including an interconnect structure overlying a substrate. The interconnect structure has a plurality of metal layers overlying over the substrate. A first dielectric layer overlies an uppermost surface of the interconnect structure. The first dielectric layer has opposing sidewalls defining a trench. A first magnetic layer is disposed within the trench and conformally extends along the opposing sidewalls. Conductive wires are disposed within the trench and overlie the first magnetic layer. A second magnetic layer overlies the first magnetic layer and the conductive wires. The second magnetic layer laterally extends from over a first sidewall of the opposing sidewalls to a second sidewall of the opposing sidewalls.