Toroid Inductor in IC Package via Substrate Cavity and TSVs
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Solution Overview
Problem
Inductors in integrated circuit (IC) packages face limitations in supporting high current due to size constraints, resulting in high resistance and low quality (Q) factors, and the removal of solder balls near inductors to improve performance compromises structural stability.
Innovation Solution
A toroid inductor design is implemented within a semiconductor device, featuring a substrate with cavities and through-substrate vias (TSVs) for interconnects, which includes a set of windings and an interconnect material like solder balls to enhance inductance and Q factor without sacrificing structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder balls are removed near the inductor to improve inductance and Q factor, then inductor performance is improved, but structural stability of the packaging substrate is compromised
Solution Approach 1:
The patent extracts the solder balls from the region near the inductor to eliminate their harmful effect on magnetic flux. By removing these interfering solder balls, the inductor achieves better inductance and Q factor without the performance degradation caused by nearby solder balls disrupting the magnetic field.
Solution Approach 2:
The patent transitions from a planar inductor design to a three-dimensional toroidal inductor structure that wraps around a cavity. This dimensional change allows the inductor to utilize the vertical space and cavity structure, creating a more efficient magnetic path that is less susceptible to interference from remaining solder balls and achieves superior performance within the same footprint.
2Power
If the inductor size is increased to support high current, then current capability is improved, but the available real estate in the IC package is exceeded
Solution Approach 1:
The patent employs a three-dimensional toroidal structure that utilizes the vertical dimension and wraps around a cavity, transforming the inductor from a planar two-dimensional layout to a three-dimensional configuration. This allows the inductor to achieve larger effective area and better current handling capability without increasing the footprint on the packaging substrate.
Solution Approach 2:
The toroidal inductor is nested around a cavity in the substrate, utilizing the cavity space as the core of the toroid. This nesting approach allows the inductor to be integrated within the existing substrate structure, maximizing space utilization and enabling high current capability without requiring additional packaging substrate area.
3Area of stationary object
If the inductor is located in the packaging substrate to utilize available space, then space utilization is improved, but the inductor resistance increases and Q factor decreases
Solution Approach 1:
The patent creates a three-dimensional toroidal structure that wraps around a cavity, utilizing the vertical space and substrate thickness rather than spreading the inductor planarly. This dimensional transformation reduces the effective path length and resistance while maintaining compact integration within the packaging substrate, thereby improving Q factor.
Solution Approach 2:
The toroidal geometry with its curved, continuous winding path around the cavity provides a more efficient magnetic path compared to planar spiral designs. The curved structure reduces eddy current losses and improves current distribution, resulting in lower resistance and higher Q factor while maintaining compact space utilization.
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 toroid inductor design improves inductance performance, reduces resistance, and maintains structural stability by effectively utilizing the substrate's space and interconnects, enabling better current support and quality factor values.
Implementation Method 1
a toroid inductor configured around the first cavity of the substrate. The toroid inductor includes a set of windings configured around the first cavity
Implementation Method 2
a set of through substrate vias (TSVs). The first set of interconnects is coupled to the second set of interconnects through the set TSVs
Data Source
AI summary
Some novel features pertain to an integrated device that includes a substrate, a first cavity through the substrate, and a toroid inductor configured around the first cavity of the substrate. The toroid inductor includes a set of windings configured around the first cavity. The set of windings includes a first set of interconnects on a first surface of the substrate, a set of though substrate vias (TSVs), and a second set of interconnects on a second surface of the substrate. The first set of interconnects is coupled to the second set of interconnects through the set TSVs. In some implementations, the integrated device further includes an interconnect material (e.g., solder ball) located within the first cavity. The interconnect material is configured to couple a die to a printed circuit board. In some implementations, the interconnect material is part of the toroid inductor.