High Frequency Module Groove Formation via Sacrificial Layer

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Solution Overview

Problem

Conventional high frequency modules face challenges in downsizing due to damage from laser processing during the formation of shielding grooves, which affects both the wiring electrodes and components, leading to increased module size and height.

Innovation Solution

A manufacturing method involving a sacrificial layer formed of a different resin, which is dissolved to create the shielding groove in the sealing resin layer, allowing for groove formation without damaging the components or wiring electrodes, and enabling the groove to overlap with components and wiring electrodes without separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If laser processing is used to form trenches in the sealing resin layer, then the shielding structure can be formed, but the wiring board surface layer conductor and components are damaged by the laser beam

Engineering Contradiction:

Improvetrench formation precisionVSAvoidcomponent and wiring electrode integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A sacrificial layer is introduced as an intermediary substance between the laser beam and the components/wiring board. This sacrificial layer absorbs the laser energy and is removed after trench formation, preventing direct laser damage to the underlying components and wiring electrodes while still allowing the trench to be formed in the sealing resin layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sacrificial layer is a temporary, disposable element used only during the manufacturing process. It is applied to protect sensitive areas, serves its purpose during laser processing, and is then completely removed. This disposable approach enables the use of laser processing without compromising the integrity of permanent components.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If the trench is formed separated from components to avoid laser damage, then component integrity is maintained, but the module size increases

Engineering Contradiction:

Improvecomponent integrityVSAvoidmodule size

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The sacrificial layer acts as a mediator that enables the trench to be formed directly adjacent to or even overlapping with components without causing damage. This eliminates the need for separation margins, allowing compact module design while maintaining component integrity through the protective sacrificial layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the trench depth is increased to reach the wiring electrode, then shielding effectiveness improves, but the module height increases

Engineering Contradiction:

Improveshielding effectivenessVSAvoidmodule height

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The shielding function is extracted from the trench depth requirement and relocated to the trench filling material. Instead of making the trench deep to achieve shielding, the trench is filled with conductive material that provides the shielding effect, allowing shallow trenches and reduced module height while maintaining shielding effectiveness.

Inventive Principle:

Principle #2Taking out (Extraction)

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 method allows for the downsizing of high frequency modules by preventing damage to components and wiring electrodes during groove formation, resulting in a reduced module size and improved reliability.

Implementation Method 1

The sacrificial layer is formed of a resin different from a resin of the sealing resin layer, and in the removal step, the groove is formed by dissolving and removing the resin of the sacrificial layer

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

a shield film forming step of forming a shield film that coats a surface of the sealing resin layer

Methodology Applied

Scientific EffectCoating/Deposition: Deposition (physical)

Data Source

PatentUS11282797B2Manufacturing method of high frequency module and high frequency module having groove in sealing resin layer

Publication Date: 2022.03.22 MURATA MFG CO LTD

AI summary

A high frequency module having a groove for shielding formed in a sealing resin layer achieves downsizing without damaging wiring electrodes formed on a wiring board or mounting components. A manufacturing method of a high frequency module includes mounting components on an upper surface of a wiring board, and then forming a sacrificial layer for forming a groove. The method further includes forming a sealing resin layer for sealing the components and the sacrificial layer, and dissolving and removing the sacrificial layer to form the groove for shielding. Finally, the method includes forming a shield film coating the surface of the sealing resin layer, and the high frequency module is manufactured. With this method, even when the groove is formed at a position overlapping with the component or a surface layer wiring electrode, the high frequency module can be downsized without damaging the component or the surface layer wiring electrode.