Vibration Device Metal Bump Stress Reduction

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Solution Overview

Problem

Existing vibration devices, such as quartz crystal oscillators, face issues with stress-induced deterioration due to differences in linear expansion coefficients between the quartz crystal vibrator element and the integrated circuit component, and outgassing from resin materials affects frequency characteristics.

Innovation Solution

A vibration device design that incorporates a vibrator and a circuit component within a package using metal bumps to support the components without resin material, with a relay substrate between them, reducing stress and eliminating outgassing issues by using a metal bump configuration that minimizes overlap and optimizes thermal transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the vibrator and the integrated circuit component are joined to each other via metal bumps, then the connection strength is improved, but the stress induced in the vibrator increases due to the difference in the coefficient of linear expansion

Engineering Contradiction:

Improveconnection strengthVSAvoidstress in vibrator

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

A resin-free support structure is introduced as an intermediary component between the vibrator and the integrated circuit component. This support structure serves as a mediator that provides mechanical support while having a coefficient of linear expansion matched to the vibrator, thereby reducing stress transmission during thermal cycling while maintaining the strong electrical connection provided by metal bumps.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the vibrator and the integrated circuit component are joined to each other via electrically conductive resin, then the joining process is simplified, but outgassing from the resin causes deterioration of the frequency characteristics

Engineering Contradiction:

Improvejoining process simplicityVSAvoidfrequency characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The resin material is completely removed from the joining process. Instead of using electrically conductive resin, the invention employs metal bumps for electrical connection and a resin-free support structure for mechanical support. This extraction of the harmful resin material eliminates the outgassing problem that deteriorates frequency characteristics while maintaining manufacturing simplicity through standardized bump bonding processes.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of manufacture

If resin material is used to join the components in the package, then the components are easily incorporated, but gas produced from the resin material during heat treatment causes problems

Engineering Contradiction:

Improvecomponent incorporationVSAvoidoutgassing

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention replaces permanent resin bonding material with metal bumps that are joined through a reliable metallurgical bond. The metal bumps serve as both electrical connectors and mechanical support structures, eliminating the need for resin materials that would outgas during subsequent heat treatments, thereby removing the harmful outgassing effect while maintaining ease of component incorporation.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 stress on the vibrator, prevents outgassing, and enhances the frequency-temperature characteristics of the vibration device, improving its reliability and performance.

Implementation Method 1

since the vibrator is supported by the circuit component via the relay substrate, stress induced in the vibrator can be reduced even in the situation in which the first to third metal bumps are used

Methodology Applied

Scientific EffectStress distribution:

Implementation Method 2

use of a metal bump configuration that minimizes overlap and optimizes thermal transfer

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10784835B2Vibration device, electronic apparatus, and vehicle

Publication Date: 2020.09.22 SEIKO EPSON CORP

AI summary

A vibration device including a vibrator, a circuit component, a relay substrate disposed between the vibrator and the circuit component, a package that accommodates the vibrator, the circuit component, and the relay substrate, a first metal bump that joins the circuit component to the package, a second metal bump that joins the relay substrate to the circuit component, and a third metal bump that joins the vibrator to the relay substrate.