Acoustic Resonator Package Bonding Structure for FBAR Hermeticity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Hermeticity of film bulk acoustic resonator (FBAR) packages is critical for reliability, but existing bonding methods can lead to defects due to silicon exposure and metal diffusion during thermocompression bonding.

Innovation Solution

The acoustic resonator package incorporates a cap with protrusions and trenches, and protective layers of chromium, titanium nitride, tantalum nitride, or similar materials on the bonding surface to prevent silicon exposure and metal diffusion, enhancing hermeticity and bonding strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thermocompression bonding is used to bond the substrate and cap, then bonding strength is improved, but silicon exposure and metal diffusion occur causing defects

Engineering Contradiction:

Improvebonding strengthVSAvoidhermeticity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

A bonding layer is introduced as an intermediary between the substrate and cap. This bonding layer prevents direct contact between silicon and metal during thermocompression bonding, thereby preventing silicon exposure and metal diffusion while maintaining bonding strength and hermeticity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bonding layer is formed in advance on the substrate or cap before the thermocompression bonding process. This preliminary action ensures that the protective barrier is already in place to prevent silicon exposure and metal diffusion during the subsequent bonding operation.

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If the cap structure is simplified without protrusions and trenches, then device complexity is reduced, but bonding precision and hermeticity deteriorate

Engineering Contradiction:

Improvecap structure complexityVSAvoidbonding precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

Protrusions are formed at specific local regions of the cap where bonding contact is required. This localized structural modification concentrates the bonding force at precise points, improving bonding precision and hermeticity without significantly increasing overall device complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The cap structure is segmented into protrusions and trenches, creating distinct functional regions. The protrusions provide precise bonding contact points while the trenches prevent excessive metal diffusion, achieving improved bonding precision without excessive complexity increase.

Inventive Principle:

Principle #1Segmentation

3Reliability

If protective layers are added on the bonding surface, then hermeticity and bonding strength are improved, but manufacturing complexity increases

Engineering Contradiction:

ImprovehermeticityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The bonding layer is formed using composite material deposition techniques, combining multiple material properties in a single layer. This approach achieves improved hermeticity and bonding strength while minimizing the number of separate manufacturing steps required.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The bonding layer's thickness and material composition are optimized to achieve the required hermeticity and bonding strength within standard manufacturing tolerances. By carefully controlling layer parameters, the manufacturing process remains simple while achieving improved reliability.

Inventive Principle:

Principle #35Parameter changes

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 improves hermeticity and bonding strength, minimizing defects and maintaining reliability of the FBAR package.

Implementation Method 1

protective layers of chromium, titanium nitride, tantalum nitride, or similar materials on the bonding surface to prevent silicon exposure and metal diffusion

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

bonding methods can lead to defects due to silicon exposure and metal diffusion during thermocompression bonding

Methodology Applied

Scientific EffectThermocompression bonding:

Data Source

PatentUS12556158B2Acoustic resonator package

Publication Date: 2026.02.17 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

An acoustic resonator package includes: a substrate; an acoustic resonator disposed on the substrate; a cap disposed on the substrate and the acoustic resonator; and a bonding portion bonding the substrate and the cap to each other. The cap includes a central portion accommodating the acoustic resonator, and an outer portion disposed outside of the central portion and having a bonding surface. The outer portion includes protrusions in contact with the bonding portion, and at least one trench disposed between the protrusions. The acoustic resonator package further includes a first protective layer and a second protective layer, the first protective layer and the second protective layer being disposed on a region of the bonding surface formed on each of the protrusions.