High Frequency Module Recess Shield Film

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Solution Overview

Problem

The formation of a shield wall in high frequency modules using laser beam machining or dicing machines can negatively impact the wiring board and degrade the inter-component shield performance, while also compromising the mechanical strength of the module.

Innovation Solution

A recess is formed in the sealing resin layer to expose an electroconductive member without reaching the wiring board's surface, with a shield film covering the recess's walls, allowing the electroconductive member to function as an inter-component shield and maintaining performance without damaging the resin layer's integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a through-groove is formed in the sealing resin layer by laser beam machining or dicing machine to create an inter-component shield wall, then the inter-component shield performance is improved, but the wiring board is negatively impacted and the mechanical strength of the module is reduced

Engineering Contradiction:

Improveinter-component shield performanceVSAvoidmechanical strength of the module

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies partial action by forming a recess that exposes only part of the electroconductive member rather than creating a through-groove. The recess has a bottom surface that stops before reaching the wiring board, exposing sufficient portion of the electroconductive member to provide inter-component shielding while preserving the integrity and mechanical strength of the sealing resin layer and wiring board.

Inventive Principle:

Principle #16Partial or excessive action

2Reliability

If a shield wall is formed by creating a through-groove in the sealing resin layer, then the inter-component shield characteristics are improved, but the wiring board is damaged

Engineering Contradiction:

Improveinter-component shield characteristicsVSAvoiddamage to wiring board

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The recess is designed to expose only the necessary portion of the electroconductive member without penetrating through the sealing resin layer to the wiring board. This partial exposure provides adequate inter-component shielding characteristics while avoiding damage to the wiring board, thus resolving the contradiction between shielding performance and board integrity.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If a through-groove is formed to create an inter-component shield, then the shield performance is improved, but the mechanical strength of the sealing resin layer is degraded

Engineering Contradiction:

Improveinter-component shield performanceVSAvoidmechanical strength of the sealing resin layer

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

Instead of creating a through-groove that completely penetrates the sealing resin layer, the patent forms a recess that stops at a bottom surface within the resin layer. This partial-depth recess exposes sufficient electroconductive member for shielding while maintaining the structural integrity and mechanical strength of the sealing resin layer.

Inventive Principle:

Principle #16Partial or excessive action

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 configuration reduces the impact on the wiring board, maintains inter-component shield characteristics, and enhances mechanical strength by allowing the shield film to function effectively as an inter-component shield, while also effectively shielding low-frequency noises with the optional inclusion of a magnetic film.

Implementation Method 1

a shield film that covers at least the opposite surface and the side surfaces of the sealing resin layer... the shield film further covers a wall surface of the recess and the exposed part of the electroconductive member

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

the electroconductive member is a conductor by itself or has a tabular conductor of which one surface faces the first component and the other surface faces the second component

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

effectively shielding low-frequency noises with the optional inclusion of a magnetic film

Methodology Applied

Scientific EffectMagnetic shielding: Magnetic Field

Data Source

PatentUS11178778B2High frequency module

Publication Date: 2021.11.16 MURATA MFG CO LTD

AI summary

A high frequency module 1a includes a wiring board 2, multiple components 3a to 3d mounted on an upper surface 2a of the wiring board 2, a shield component 4 mounted between the component 3b and the component 3c, a sealing resin layer 5 that covers the components 3a to 3d and the shield component 4, and a shield film 6 that covers the surface of the sealing resin layer. A recess 10 is formed in an upper surface 5a of the sealing resin layer 5 so as to expose the shield component 4. The recess 10 is formed within a region surrounded by edges of the sealing resin layer 5 so as not to reach the side surfaces of the sealing resin layer 5. The shield film 6 further covers wall surfaces 10a of the recess 10 and part of the shield component 4 exposed through the recess 10.