Decoupled Waveguide Packaging for Low-Stress RF Semiconductor Assembly

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Solution Overview

Problem

Automotive radar systems in vehicles require efficient semiconductor device packaging that minimizes cost and maximizes reliability while providing low loss RF signal performance, which existing technologies have not adequately addressed.

Innovation Solution

A semiconductor device with a packaged assembly featuring a physically decoupled overlapping waveguide structure affixed to a common substrate, where the waveguide structure is designed to propagate RF signals without contacting the packaged assembly, reducing stress and improving reliability while maintaining compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the waveguide structure is integrated with the packaged assembly, then RF signal transmission is achieved, but package stress increases and reliability deteriorates

Engineering Contradiction:
Improvepackage reliabilityVSAvoidpackage stress
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The waveguide structure is segmented from the packaged assembly into a separate component. The packaged assembly (containing the semiconductor die and launcher structure) and the waveguide structure are manufactured independently and then positioned relative to each other, eliminating stress transmission between these components while maintaining RF signal coupling through the encapsulant material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The encapsulant material serves as an intermediary between the packaged assembly and the waveguide structure. It provides both mechanical isolation (preventing stress transmission) and electromagnetic coupling (enabling RF signal transmission). The encapsulant's dielectric properties allow it to mediate between the physical separation needed for stress reduction and the electrical connection needed for RF performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the waveguide structure is physically coupled to the packaged assembly, then structural support is provided, but stress is transmitted and reliability is reduced

Engineering Contradiction:
Improvestructural supportVSAvoidpackage reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The encapsulant material acts as an intermediary that provides structural support for mounting the waveguide structure while simultaneously isolating it from stress transmitted by the packaged assembly. This allows the waveguide to be securely positioned without direct mechanical coupling that would transmit stress and reduce reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

By segmenting the waveguide structure from the packaged assembly, the design allows each component to be optimized independently for its primary function while reducing coupled stress. The waveguide structure provides RF signal transmission without bearing mechanical stress from the packaged assembly, improving overall reliability.

Inventive Principle:
Principle #1Segmentation

3Area of stationary object

If a compact packaging design is implemented, then footprint is reduced, but RF signal loss may increase

Engineering Contradiction:
Improvepackage footprintVSAvoidRF signal loss
Core Design Contradiction:
Area of stationary objectVSLoss of energy

Solution Approach 1:

The design transitions from a planar integration approach to a three-dimensional stacked configuration. The waveguide structure is positioned above the packaged assembly in the vertical dimension, allowing compact footprint in the horizontal plane while maintaining adequate spacing for low-loss RF signal transmission through the encapsulant material.

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

Solution Approach 2:

The encapsulant material serves as an intermediary that enables compact packaging while minimizing RF signal loss. Its dielectric properties are optimized to allow efficient RF signal coupling between the launcher structure and waveguide through the encapsulant, achieving both compactness and low loss performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution reduces package stress and enhances reliability while providing low loss RF signal performance in a compact footprint, effectively addressing the cost and efficiency challenges of automotive radar systems.

Implementation Method 1

The waveguide structure includes a waveguide opening over an antenna launcher of the launcher structure allowing propagation of radio frequency (RF) signals

Methodology Applied
Scientific EffectWaveguide: Waveguide

Data Source

PatentEP3840114B1Semiconductor device with waveguide and method therefor
Publication Date: 2024.05.29 NXP USA INC
  • EP3840114B1 patent drawingFigure 1
  • EP3840114B1 patent drawingFigure 2
  • EP3840114B1 patent drawingFigure 3

AI summary

A method of manufacturing a semiconductor device is provided. The method includes forming an assembly including placing a semiconductor die and a launcher structure on a carrier substrate, encapsulating at least a portion of the semiconductor die and the launcher structure, and applying a redistribution layer on a surface of the semiconductor die and a surface of the launcher structure to connect a bond pad of the semiconductor die with an antenna launcher of the launcher structure. The assembly is attached to a substrate and a waveguide overlapping the assembly is attached to the substrate. The waveguide structure is physically decoupled from the assembly.