Quartz Resonator Coupling Layout for Stable Frequency Trimming

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Solution Overview

Problem

Existing resonator elements face challenges in miniaturization due to stress concentration and resonance frequency instability, particularly when the length of the base portion is shortened, leading to inaccurate frequency adjustment and reduced yield in manufacturing.

Innovation Solution

A method for manufacturing resonator elements involves forming a coupling portion that extends from only one edge of the base portion, with a constricted portion and groove features to reduce stress and enhance singulation, allowing for precise control of resonance frequencies and miniaturization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the length of the base portion is shortened for miniaturization, then the resonator element size is reduced, but stress concentration occurs at the break-off portion leading to manufacturing failure

Engineering Contradiction:

Improvebase portion lengthVSAvoidbreak-off portion strength

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The patent applies local quality by providing a reinforcement portion at the specific location of the break-off portion, where stress concentration occurs. This reinforcement portion has a greater thickness than the base portion, creating a localized structural enhancement precisely where needed to prevent stress-induced failure during miniaturization.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the base portion into multiple regions with different thickness characteristics: the base portion, the break-off portion, and the reinforcement portion. This segmentation allows each region to serve its specific function - the reinforcement portion prevents stress concentration at the break-off portion while the overall structure maintains miniaturized dimensions.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the break-off portion is provided at both edges of the base portion, then the resonator element is firmly fixed to the wafer, but the resonance frequency of spurious mode increases remarkably causing mode coupling

Engineering Contradiction:

Improvefixing reliabilityVSAvoidresonance frequency control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies asymmetry by providing the break-off portion at only one edge of the base portion rather than at both edges. This asymmetric configuration reduces the fixing strength between the resonator element and the wafer, thereby preventing remarkable increase in spurious mode resonance frequency and reducing mode coupling, while still maintaining sufficient fixing for manufacturing.

Inventive Principle:

Principle #4Asymmetry

3Reliability

If the break-off portion is provided at both edges, then the resonator element is firmly fixed to the wafer, but frequency adjustment accuracy deteriorates due to manufacturing variations

Engineering Contradiction:

Improvefixing reliabilityVSAvoidfrequency measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The asymmetric configuration with break-off portion at only one edge reduces the overall fixing strength, making the resonance frequency less sensitive to manufacturing variations in the break-off portion. This improves frequency measurement accuracy and adjustment precision while maintaining adequate fixing reliability for the manufacturing process.

Inventive Principle:

Principle #4Asymmetry

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 approach enables the production of resonator elements with improved miniaturization and reduced thermoelastic loss, while maintaining precise frequency control and increasing manufacturing yield by separating the in-phase and opposite-phase flexural vibration modes.

Implementation Method 1

a main mode (a flexural vibration mode in which the pair of vibrating arms alternately separate from and approach each other repeatedly in the plan view)

Methodology Applied

Scientific EffectFlexural vibration: Vibration

Implementation Method 2

the resonance frequency F0 of the main mode and the resonance frequency F1 of the spurious mode

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 3

an outer shape forming step of etching a substrate to form, in a plan view, the base portion, the vibrating arms, a frame portion surrounding the base portion and the vibrating arms

Methodology Applied

Scientific EffectEtching:

Data Source

PatentUS10305426B2Method for manufacturing resonator element, wafer, resonator element, resonator, oscillator, real-time clock, electronic apparatus, and moving object

Publication Date: 2019.05.28 SEIKO EPSON CORP

AI summary

A method for manufacturing a resonator element includes: an outer shape forming step of etching a substrate to form, in a plan view, a base portion, a pair of vibrating arms extending from the base portion in a first direction, a frame portion surrounding the base portion and the vibrating arms, and a coupling portion coupling the base portion with the frame portion; and a singulation step of cutting the coupling portion to singulate the resonator element. In the outer shape forming step, the coupling portion is formed so as to extend, in the plan view, from only one edge side of the base portion in a direction along a second direction orthogonal to the first direction and be connected with the frame portion.