Mold-Embedded Inductor Packaging for Thinner Power Modules

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Solution Overview

Problem

Conventional discrete surface mount inductors used in power management systems for Ultra Low Power (ULP) IoT and High-End Computing (HEC) applications are undesirably large, constraining the minimum achievable form factor of device packages due to their size, particularly in the z-dimension, which increases the thickness of the device package.

Innovation Solution

A semiconductor device package with an inductor embedded in mold material, where the inductor core is formed within a cavity in the mold material, and conductive winding traces are embedded around the core, allowing for a more compact design by integrating the inductor directly into the package substrate and encapsulating it with mold material, using active mold packaging and laser direct structuring processes for cavity formation and electroless plating to create conductive elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If discrete surface mount inductors are used in power management systems, then the inductor function is achieved, but the package size and thickness increase undesirably

Engineering Contradiction:
Improveinductor volumeVSAvoidpackage structure complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The inductor is merged with the package substrate by embedding it within the mold material that forms the package body. The inductor core and winding traces are integrated into the mold compound, eliminating the need for separate discrete inductor components and reducing overall package volume while maintaining the inductor's electrical function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The inductor structure transitions from a three-dimensional discrete component to a planar integrated structure. The winding traces are formed as two-dimensional patterns on the package substrate, and the core is embedded within the mold material, effectively reducing the inductor's vertical profile and enabling thinner package designs.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If discrete surface mount inductors are used, then inductor functionality is provided, but the minimum achievable form factor of the device package is constrained

Engineering Contradiction:
Improvepackage form factor flexibilityVSAvoidinductor volume
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The inductor is merged with the package substrate by embedding it within the mold material that forms the package body. The inductor core and winding traces are integrated into the mold compound, eliminating the need for separate discrete inductor components and reducing overall package volume while maintaining the inductor's electrical function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The inductor's physical parameters are changed by reducing its volume and integrating it into the package substrate. The winding traces are formed as thin planar patterns rather than bulky three-dimensional coils, and the core is embedded within the mold material, enabling smaller form factors and greater adaptability to different package size requirements.

Inventive Principle:
Principle #35Parameter changes

3Volume of stationary object

If the inductor is embedded in mold material, then the package size is reduced, but additional fabrication steps are required

Engineering Contradiction:
Improvepackage volumeVSAvoidfabrication process complexity
Core Design Contradiction:
Volume of stationary objectVSEase of manufacture

Solution Approach 1:

Cavities for the inductor core and winding traces are formed in the mold material before the final molding step. Conductive traces are deposited on the substrate in advance, and the mold material is prepared with embedded cavities that will contain the inductor components during the molding process, integrating inductor formation into the package manufacturing flow.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Traditional mechanical assembly of discrete inductors is replaced with a integrated molding process. The inductor components are embedded within the mold material during the molding step itself, eliminating separate assembly operations and reducing manufacturing complexity despite the integrated structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 reduces the volume occupied by the inductor, allowing for a more compact package design, improving performance by placing the inductor in closer proximity to the integrated circuit die and reducing the overall package size, thereby addressing the size constraints imposed by conventional discrete surface mount inductors.

Implementation Method 1

forming the winding cavities and the core cavity in the first mold material via laser ablation

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

forming the lateral winding traces in the winding cavities, and forming the conductive sidewalls in the core cavity via electroless plating

Methodology Applied
Scientific EffectElectroless plating: Electroplating

Implementation Method 3

forming the inductor core in the core cavity via electroless plating

Methodology Applied
Scientific EffectElectroless plating: Electroplating

Data Source

PatentEP4322187A1Package with mold-embedded inductor and method of fabrication therefor
Publication Date: 2024.02.14 NXP USA INC
  • EP4322187A1 patent drawingFigure 1
  • EP4322187A1 patent drawingFigure 2A
  • EP4322187A1 patent drawingFigure 2B

AI summary

A semiconductor device package may include a package substrate, mold material formed over the package substrate, and a mold-embedded inductor that is embedded in the mold material. The mold-embedded inductor may be coupled to a die, such as a power management integrated circuit die, which may also be embedded in the mold material. The mold-embedded inductor may be formed by forming conductive traces and an inductor core in the mold material. For example, an active mold packaging (AMP) process and corresponding laser direct structuring (LDS) processes may be performed to form openings in the mold material and to activate surfaces of the mold material to facilitate subsequent plating of conductive material. Activated surfaces of the mold material may have micro-rough texture and may include bulk conductive material formed via the application of laser energy to additives in the mold material during the LDS process(es).