SIP Inductor Gap Prevents Dielectric Breakdown
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Solution Overview
Problem
System-in-package (SIP) devices with inductors face damage due to resistive breakdown caused by electric fields between the inductor body and leadframe, especially under high voltage and current conditions, leading to failures and increased costs when attempting to mitigate these issues with additional coatings or substrate changes.
Innovation Solution
Incorporating a gap of at least 100 μm between the inductor body and the leadframe to reduce electric field formation, achieved by designing the inductor with a standoff distance that is filled with molding compound, preventing direct contact and thus preventing dielectric breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the inductor body is placed close to the leadframe to reduce package size, then device integration is improved, but electric field formation causes resistive breakdown and damage
Solution Approach 1:
The patent introduces an intermediary material (molding compound or insulating material) between the inductor body and the leadframe. This intermediary prevents direct contact and blocks the electric field path, eliminating resistive breakdown while allowing the inductor to be positioned close to the leadframe for compact packaging.
Solution Approach 2:
The patent creates a vertical separation dimension by positioning the inductor body at a distance from the leadframe surface (e.g., 0.05 inches or 1.27 mm gap). This dimensional separation in the vertical direction allows compact horizontal integration while preventing electric field formation through vertical spacing.
2Reliability
If additional coatings or substrate changes are applied to prevent breakdown, then reliability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the electric field problem from the system by removing the direct contact path between the inductor body and leadframe. Instead of adding complex coatings or modifying substrates, the solution simply eliminates the harmful electric field formation through spacing and intermediary materials, simplifying the overall structure.
Solution Approach 2:
The patent uses inexpensive, readily available materials (standard molding compounds or insulating materials already present in the package) rather than requiring specialized coatings or expensive substrate modifications. This approach maintains reliability while avoiding increased manufacturing complexity and cost.
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 solution effectively prevents damage to the inductor and other components in SIP devices by reducing electric field intensity, thereby enhancing reliability and reducing costs associated with additional coatings or substrate modifications.
Implementation Method 1
damage is caused by a resistive breakdown in the inductor body due to an electric field that forms between the body of the inductor and the leadframe
Implementation Method 2
the portion of the inductor body between the inductor terminals spaced from the first surface of the first leadframe by a gap of at least 100 μm
Data Source
AI summary
Described examples include a system in package (SIP) device, including: a first leadframe having a first surface and a second surface opposite the first surface; an integrated circuit die including solder bumps on a first surface and having a second opposite surface, the solder bumps mounted to the second surface of the first leadframe; a second leadframe having a first surface including a die pad portion, and a second opposite surface, the die pad portion attached to the second surface of the integrated circuit die; and an inductor mounted to the first surface of the first leadframe, the inductor having terminals with exterior portions electrically connected and mechanically connected to the first surface of the first leadframe, the inductor terminals spaced from one another by a portion of an inductor body, the portion of the inductor body between the inductor terminals spaced from the first surface of the first leadframe by a gap of at least 100 μms.