Multilayer Sensor Package Covering for Reduced RF Losses

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Solution Overview

Problem

As electronics become smaller and more portable, closely spaced devices experience interference from radio frequency signals, leading to errors in sensor readings and heat generation due to induced electric currents, which conventional protective coverings fail to adequately address.

Innovation Solution

A multilayer protective covering is used, comprising a core layer and an electrically conductive layer, with a void to prevent direct contact, allowing induced currents to flow primarily through the conductive layer, reducing radio frequency losses and heat generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conventional protective covering is used to shield the sensor from radio frequency signals, then the sensor is physically protected, but radio frequency signals induce electric currents in the covering that generate heat at the sensor

Engineering Contradiction:
Improveradio frequency interferenceVSAvoidheat generation at sensor
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The protective covering is divided into multiple layers: an outer non-conductive core layer and an inner electrically conductive layer. This segmentation allows each layer to perform its specific function - the core layer provides structural support and RF shielding, while the conductive layer directs induced currents away from the sensor, reducing heat generation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrically conductive layer acts as an intermediary between the RF environment and the sensor. It intercepts RF signals and conducts induced currents through designated paths to ground, preventing these currents from reaching the sensor and converting to heat at the sensor location.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If an electrically conductive protective covering is used to block radio frequency signals, then radio frequency shielding is improved, but the weight and cost of the package increases

Engineering Contradiction:
Improveradio frequency shieldingVSAvoidpackage weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The protective covering uses a composite structure combining a non-conductive core layer (providing structural support and basic RF shielding) with an electrically conductive layer (providing enhanced RF shielding). This composite approach achieves superior RF shielding performance while keeping the overall weight lower than a solid conductive covering would require.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The electrically conductive layer is applied selectively - primarily on the inner surface facing the sensor and in specific regions where RF shielding is most critical. This localized application provides effective RF protection while minimizing the amount of conductive material used, thereby reducing weight and cost.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If a thick electrically conductive layer is used to reduce radio frequency losses, then radio frequency shielding is improved, but the manufacturing cost and complexity increase

Engineering Contradiction:
Improveradio frequency lossesVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The conductive shielding function is segmented into a separate layer rather than requiring a thick monolithic conductive structure. The core layer handles structural requirements while the conductive layer handles RF shielding, allowing each to be optimized independently and simplifying manufacturing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The composite layering of non-conductive core material with a thinner conductive overlay achieves effective RF shielding with reduced material thickness compared to a solid conductive structure. This composite approach simplifies manufacturing processes and reduces overall complexity while maintaining shielding effectiveness.

Inventive Principle:
Principle #40Composite materials

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 multilayer protective covering effectively minimizes radio frequency interference and heat transfer to enclosed devices, providing mechanical stability, electrical conductivity, and corrosion resistance while reducing weight and cost.

Implementation Method 1

an electrically conductive layer 142. The multilayer protective covering 120 is configured to reduce radio frequency losses

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

radio frequency signals that are incident on the sensor package may interfere directly with sensor readings or may induce electric currents in the sensor package

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

An empty space or void 112 is formed by the multilayer protective covering 120 such that the multilayer protective covering 120 does not directly contact the device 117 enclosed within

Methodology Applied
Scientific EffectPhysical isolation: Physical Containment

Implementation Method 4

The multilayer protective covering effectively minimizes radio frequency interference and heat transfer to enclosed devices

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3421415B1Device package with reduced radio frequency losses
Publication Date: 2026.03.11 INFINEON TECHNOLOGIES AG
  • EP3421415B1 patent drawingFigure 1~2
  • EP3421415B1 patent drawingFigure 3A~3D
  • EP3421415B1 patent drawingFigure 4A~4D

AI summary

A device package includes a semiconductor device. The semiconductor device is disposed on a substrate. The device package further includes a covering. The covering is disposed on the substrate and surrounds the semiconductor device. The covering includes a void, a first layer, and a second layer. The void is between an interior surface of the covering and the semiconductor device. The first layer has a first electrical conductivity and a first thickness. The second layer is disposed under the first layer. The second layer has a second electrical conductivity and a second thickness. The first electrical conductivity is greater than the second electrical conductivity. The first thickness is less than the second thickness.