Composite SAW Substrate Groove Structure for Stronger Piezoelectric Bonding

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Solution Overview

Problem

Existing acoustic wave devices face issues with piezoelectric plates falling off due to insufficient bonding strength and damage from transverse deformation.

Innovation Solution

A composite substrate is created by embedding a piezoelectric plate into a groove on a base, with bonding layers and stress compensation layers to enhance bonding strength and prevent deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the piezoelectric plate is bonded directly on the substrate surface, then the manufacturing process is simple, but the bonding strength is insufficient and the piezoelectric plate falls off

Engineering Contradiction:

Improvebonding process simplicityVSAvoidbonding strength

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent transitions from surface-level bonding (2D) to embedding the piezoelectric plate into a groove structure (3D), creating multi-dimensional mechanical interlocking that significantly enhances bonding strength while maintaining manufacturing feasibility

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The piezoelectric plate is nested within a groove formed in the substrate, creating a cavity-embedded structure where the plate fits into the groove and is bonded to the substrate walls, providing both mechanical support and strong adhesion

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of manufacture

If the piezoelectric plate is bonded on the substrate, then the device can be manufactured, but the piezoelectric plate is damaged due to transverse deformation

Engineering Contradiction:

Improvedevice manufacturabilityVSAvoidpiezoelectric plate integrity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The groove structure embeds the piezoelectric plate, providing lateral support from the groove walls that prevents transverse deformation and cracking during device operation and manufacturing processes

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The groove structure is formed beforehand to provide mechanical support and constraint to the piezoelectric plate before any deformation or stress occurs, preventing damage in advance rather than correcting it later

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If piezoelectric plates of different sizes are used on different production lines, then each production line is optimized for its size, but the adaptability across production lines is reduced

Engineering Contradiction:

Improveproduction line optimizationVSAvoidproduction line flexibility

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The groove-based embedding structure provides a universal mounting approach that can accommodate piezoelectric plates of various sizes by adjusting groove dimensions, allowing the same substrate design to work across different production line scales (6-inch, 8-inch, 12-inch wafers)

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The groove dimensions (depth, width, shape) can be adjusted as parameters to match different piezoelectric plate sizes while maintaining the same fundamental embedding structure, enabling flexibility across production lines without redesigning the entire substrate

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 the bonding strength between the piezoelectric plate and the substrate, reduces the risk of damage from transverse deformation, and allows for the use of piezoelectric plates of different sizes across various production lines.

Implementation Method 1

a bonding layer, the bonding layer being between the piezoelectric plate and the base

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

By embedding the piezoelectric plate into the first groove, the sidewall of the first groove may obstruct the movement of the piezoelectric plate

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Data Source

PatentUS12224730B2Manufacturing method of a composite substrate of an acoustic wave resonator

Publication Date: 2025.02.11 NINGBO SEMICON INT CORP

AI summary

The present invention discloses a composite substrate for manufacturing an acoustic wave resonator and a Surface Acoustic Wave (SAW) resonator, and a manufacturing method thereof. The manufacturing method of the composite substrate includes: providing a base, wherein the base includes a first surface and a second surface that are opposite to each other; and a first groove sunken towards the second surface is formed on the first surface; and providing a piezoelectric plate, wherein the piezoelectric plate is matched with the first groove in shape, and a bottom of the first groove is integrated with the piezoelectric plate by bonding; and the composite substrate includes: a base, wherein the base includes a first surface and a second surface that are opposite to each other; and a first groove sunken towards the second surface is provided on the first surface; and a piezoelectric plate, wherein the piezoelectric plate is embedded into the first groove, and a top of the piezoelectric plate is higher than the first surface or flush with the first surface.