3D Inductor Crossbar Structures for Semiconductor Packages
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Solution Overview
Problem
The challenge is to design a semiconductor device with a 3D inductor structure that is cost-effective and compatible with both 2.5D and 3D integrated circuit packages, while minimizing the height constraint imposed by the passivation layer and reducing out-of-phase current effects.
Innovation Solution
The semiconductor device incorporates a substrate with patterned conductive layers and dielectric layers forming crossbars and columnar structures that are electrically connected to minimize out-of-phase current, allowing for a reduced package size and increased Q factor and inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the height of the 3D inductor structure is increased to improve inductance and Q factor, then the inductance and Q factor are improved, but the passivation layer thickness must be increased which results in higher cost
Solution Approach 1:
The patent transitions from traditional planar 2D inductor layouts to a three-dimensional structure utilizing multiple conductive layers stacked vertically. The inductor comprises bottom crossbars in a first conductive layer, side crossbars in a second conductive layer, and top crossbars in a third conductive layer, creating a 3D configuration that increases inductance without proportionally increasing passivation layer thickness. This dimensional transformation allows the magnetic flux to be contained more effectively within a compact vertical space, improving the inductance-to-area ratio and reducing the need for excessive passivation thickness.
Solution Approach 2:
The patent implements a nested structure where the magnetic flux generated by bottom crossbars is contained and utilized by side crossbars, which in turn are contained and utilized by top crossbars. Each layer of crossbars is positioned to leverage the magnetic field of the previous layer, creating a nested magnetic flux containment system. This nested configuration maximizes the use of magnetic flux across multiple layers, increasing overall inductance while maintaining a compact structure that does not require proportional increases in passivation layer thickness.
2Reliability
If the height of the 3D inductor structure is increased to improve inductance, then the inductance is improved, but the package size must be increased to accommodate the greater height
Solution Approach 1:
The patent redistributes the inductor structure across the vertical dimension by stacking conductive layers, with bottom crossbars in a first layer, side crossbars in a second layer, and top crossbars in a third layer. This vertical stacking allows the magnetic flux to be contained within a compact footprint while achieving high inductance through the three-dimensional configuration. The side crossbars connect the bottom and top crossbars vertically, creating a nested magnetic flux containment system that maximizes inductance density without proportionally increasing package volume.
3Length of stationary object
If the thickness of the passivation layer is increased to accommodate a taller 3D inductor structure, then the inductor height can be increased, but the manufacturing cost increases
Solution Approach 1:
The patent achieves increased inductor height through optimized vertical stacking of conductive layers rather than simply increasing passivation layer thickness. The side crossbars in the second conductive layer connect bottom crossbars in the first layer to top crossbars in the third layer, creating an efficient three-dimensional configuration. This approach allows the inductor to achieve greater effective height and inductance while maintaining a more compact overall structure, thereby reducing the required passivation layer thickness and associated manufacturing costs.
4Volume of moving object
If a compact 3D inductor structure is used to reduce package size, then the package size is reduced, but out-of-phase current effects increase which degrades performance
Solution Approach 1:
The patent employs asymmetric positioning and configuration of crossbars within each conductive layer to optimize current distribution and minimize out-of-phase current effects. The bottom, side, and top crossbars are strategically positioned with different orientations and spacings, creating an asymmetric structure that promotes more uniform current flow through the three-dimensional path. This asymmetric design helps reduce eddy current losses and minimizes out-of-phase current effects, thereby maintaining high Q factor and performance in the compact package.
Data Source
AI summary
A semiconductor device includes a substrate and at least one inductor on the substrate. The inductor includes top portions separated from one another, bottom portions separated from one another, and side portions separated from one other. Each side portion extends between one of the top portions and one of the bottom portions. A semiconductor device includes a substrate, a first patterned conductive layer on the substrate, a second patterned conductive layer, and at least one dielectric layer between the first patterned conductive layer and the second patterned conductive layer. The first patterned conductive layer defines bottom crossbars separated from each other, each bottom crossbar including a bend angle. The second patterned conductive layer defines top crossbars separated from each other, wherein each top crossbar is electrically connected to a bottom crossbar.