Composite SAW Substrate With Diffusion Layer for Temperature Compensation

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Solution Overview

Problem

Current high-performance radio frequency filters face challenges in temperature stability and production complexity, limiting their versatility and increasing production costs.

Innovation Solution

A composite substrate comprising a supporting layer of polycrystalline compound and a piezoelectric layer bonded with a diffusion area, where elements from the supporting layer diffuse into the piezoelectric layer, allowing for thin film formation and temperature compensation, reducing interference and maintaining stable performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temperature compensation technology is introduced into SAW filters, then temperature stability is improved, but production complexity increases

Engineering Contradiction:

Improvetemperature stabilityVSAvoidproduction complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the temperature compensation function and thin film characteristics into a single composite substrate structure. The supporting layer (polycrystalline compound) provides temperature compensation, while the piezoelectric layer (thin film) provides the filtering function. This merging eliminates the need for separate temperature compensation mechanisms, reducing production complexity while maintaining temperature stability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite materials consisting of a supporting layer made of polycrystalline compound and a piezoelectric layer made of thin film material. This composite structure integrates the temperature compensation properties of the supporting layer with the piezoelectric properties of the thin film layer, achieving both temperature stability and simplified production compared to traditional TC-SAW filters.

Inventive Principle:

Principle #40Composite materials

2Length of stationary object

If thin film technology is introduced into SAW filters, then piezoelectric layer thickness is reduced, but temperature compensation capability is lost

Engineering Contradiction:

Improvepiezoelectric layer thicknessVSAvoidtemperature compensation capability

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The patent merges the temperature compensation function with the thin film structure by creating a composite substrate where the supporting layer provides temperature compensation and the piezoelectric layer provides the thin film filtering function. This allows the piezoelectric layer to be thin while maintaining temperature compensation capability through the supporting layer.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The composite substrate uses a supporting layer of polycrystalline compound bonded to a piezoelectric layer of thin film material. The supporting layer compensates for temperature effects on the thin piezoelectric layer, enabling the use of thin films without sacrificing temperature compensation capability.

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If composite substrate structure is adopted, then versatility is improved, but manufacturing process complexity increases

Engineering Contradiction:

Improvefilter type versatilityVSAvoidbonding process complexity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The composite substrate structure serves multiple functions: it provides temperature compensation, supports thin film piezoelectric layers, and can be used for both TC-SAW and TF-SAW filter production. This multi-functionality increases versatility while the standardized bonding process reduces manufacturing complexity compared to producing different filter types separately.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 composite substrate achieves temperature compensation, reduces production difficulty, and lowers costs while maintaining electrical parameters, suitable for mass production of both TC-SAW and TF-SAW filters.

Implementation Method 1

at least one of constituent elements of the polycrystalline compound diffuse from the supporting layer to the piezoelectric layer after the bonding process, to form a diffusion area extending from the bonding main surface in a direction gradually facing away from the supporting layer in the piezoelectric layer

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS20250392283A1Composite substrate and preparation method thereof, electronic device and module

Publication Date: 2025.12.25 QUANZHOU SANAN INTEGRATED CIRCUIT CO LTD

AI summary

A composite substrate and a preparation thereof, an electronic device and a module are provided. The composite substrate includes: a supporting layer, including a polycrystalline compound; and a piezoelectric layer, including a piezoelectric material and a bonding main surface. The piezoelectric layer is disposed on the supporting layer in a manner that the bonding main surface is bonded to the supporting layer; the piezoelectric layer includes a diffusion area extending from the bonding main surface in a direction gradually facing away from the supporting layer therein; and constituent elements of the polycrystalline compound include characteristic elements different from constituent elements of the piezoelectric material, and the diffusion area includes at least one of the characteristic elements therein. The composite substrate has advantages of TC-SAW and TF-SAW, has high versatility, can reduce production difficulty, and is suitable for mass production.