Grounded Isolation Wall Layout for Doherty Amplifier Packages

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Solution Overview

Problem

Existing semiconductor device packages face challenges in reducing inductive coupling between adjacent circuits, which affects the performance of multi-path power amplifiers like Doherty power amplifiers.

Innovation Solution

Incorporating an isolation wall made of conductive material connected to ground, which separates the carrier and peaking amplifier elements, thereby reducing inductive coupling and improving signal isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an isolation wall is added to reduce inductive coupling between adjacent circuits, then signal isolation is improved, but device complexity increases

Engineering Contradiction:
Improvesignal isolationVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The isolation wall divides the package interior into separate regions for different amplifier circuits (e.g., carrier and peaking amplifiers in a Doherty amplifier). This segmentation physically separates adjacent circuits that operate at different power levels, preventing inductive coupling between them while maintaining overall package functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The isolation wall acts as an intermediary structure between adjacent amplifier circuits. It serves as a electromagnetic shield that mediates the interaction between circuits operating at different power levels, blocking unwanted inductive coupling while allowing each circuit to function independently.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a solid isolation wall structure is used to maximize shielding effect, then signal isolation is improved, but encapsulation material flow is restricted causing interior and surface defects

Engineering Contradiction:
Improvesignal isolationVSAvoidencapsulation quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The isolation wall incorporates a porous structure with multiple through-holes or slots that allow encapsulation material to flow through during the molding process. This porous design maintains the electromagnetic shielding function while enabling complete encapsulation of all components without trapping air pockets or creating voids.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The isolation wall features a three-dimensional structure with vertical extent and horizontal openings. By adding the vertical dimension with slots or holes that extend through the wall thickness, the design allows encapsulation material to access regions behind the isolation wall, ensuring complete filling while maintaining shielding effectiveness.

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

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 isolation wall effectively reduces inductive coupling between amplifier elements, enhancing the performance of multi-path amplifiers by improving signal isolation and reducing interior and surface defects in the semiconductor device package.

Implementation Method 1

an isolation wall made of conductive material connected to ground, which separates the carrier and peaking amplifier elements, thereby reducing inductive coupling and improving signal isolation

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP3211669B1Semiconductor package with isolation wall
Publication Date: 2025.04.09 NXP USA INC
  • EP3211669B1 patent drawingFigure 1
  • EP3211669B1 patent drawingFigure 2
  • EP3211669B1 patent drawingFigure 3~5

AI summary

A semiconductor device package includes an isolation wall located between a first circuit and a second circuit on a substrate. The isolation wall is configured to reduce inductive coupling between the first and second circuits during operation of the semiconductor device. Encapsulation material covers the substrate, first and second circuits, and the isolation wall. The isolation wall has features, such as indentation, along its upper edge that facilitate a flow of the encapsulation material across the isolation wall during fabrication to largely eliminate interior defects and/or visual defects on the surface of the completed semiconductor device package. For a dual-path amplifier, such as a Doherty power amplifier, the isolation wall separates the carrier amplifier elements from the peaking amplifier elements included within the semiconductor device package.