Hermetic SAW Encapsulation With External RF Connector

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Solution Overview

Problem

Surface acoustic wave (SAW) devices are vulnerable to environmental factors and bulkiness in communication devices, limiting their robustness and compactness, as well as increasing production costs due to exposed sensitive parts and lengthy communication paths.

Innovation Solution

An encapsulation system integrating a miniature coaxial radio frequency connector outside the cavity, using wire bonding, vias, or metal pads to connect the interdigital transducer directly, reducing exposure to environmental risks and simplifying production by minimizing components and space, while ensuring hermetic sealing and thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the SAW device is exposed to the environment for direct access, then the communication path is shorter and simpler, but the device becomes vulnerable to environmental factors and less robust

Engineering Contradiction:

ImproverobustnessVSAvoidenvironmental exposure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A hermetic seal (intermediary structure) is introduced between the SAW device and the external environment. This seal includes a first substrate with the SAW device, a second substrate, and a sealing joint that creates a protective barrier while allowing controlled communication through an antenna connection means, thus protecting against environmental factors while maintaining functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The SAW device is nested within a hermetic seal structure consisting of multiple substrates and sealing joints. The antenna connection means is integrated into this nested structure, allowing the device to be protected while maintaining external connectivity through the sealed interface

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of manufacture

If traditional encapsulation methods are used with exposed connection paths, then the production process is simpler, but the device bulkiness increases and production costs rise

Engineering Contradiction:

Improveproduction simplicityVSAvoiddevice compactness

Core Design Contradiction:

Ease of manufactureVSVolume of moving object

Solution Approach 1:

Multiple functions are merged into a single integrated structure: the hermetic seal simultaneously provides mechanical protection, environmental sealing, and electrical connection pathways through the antenna connection means. This consolidation eliminates the need for separate protective housings and external wiring, reducing overall device volume while maintaining manufacturing simplicity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The hermetic seal structure serves multiple purposes: it acts as a protective enclosure, an environmental barrier, and an integrated connection interface. The antenna connection means embedded in the seal provides both sealing and electrical connectivity functions, reducing the number of separate components needed

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Volume of moving object

If the antenna connection means is integrated into the encapsulation system, then the device compactness and robustness improve, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvedevice compactnessVSAvoidintegration precision

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The device is segmented into distinct functional layers: the first substrate containing the SAW device, the sealing joint, and the second substrate with the antenna connection means. This segmentation allows each component to be manufactured and tested separately with standard precision, then assembled together, reducing the overall manufacturing precision requirements compared to fully integrated monolithic structures

Inventive Principle:

Principle #1Segmentation

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 enhances the robustness, compactness, and cost-effectiveness of SAW devices by reducing environmental exposure, simplifying production, and optimizing thermal conductivity, resulting in a more reliable and versatile protection system.

Implementation Method 1

SAW devices are sensitive to the fluctuations in the resonance frequency of elastic waves on the surface of piezoelectric materials

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a sealing joint, which seals a second substrate with the base substrate so as to form a cavity enveloping the interdigital transducer

Methodology Applied

Scientific EffectHermetic sealing:

Implementation Method 3

the connection between the interdigital transducer and the antenna connection means may comprise a wire bonding

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20250023545A1System for encapsulating a surface elastic wave device

Publication Date: 2025.01.16 SOITEC SA

AI summary

A compact and robust encapsulation system for protecting a surface wave device comprises a SAW device and a sealing joint, which seals a second substrate to the base substrate of the SAW device so as to form a cavity, and an antenna connection means arranged outside the cavity on the encapsulation system.