Corrugated MEMS Microphone Cantilever for Stress-Stable Sensitivity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional piezoelectric MEMS microphones suffer from sensitivity degradation and reliability issues due to residual stress and stress gradient in thin film piezoelectric structures, leading to poor low-frequency performance and high manufacturing costs.

Innovation Solution

Incorporating a corrugated section with grooves in the distal portion of the cantilever beam to enhance rigidity and reduce bending, while maintaining sensitivity, by using a substrate with a cantilever beam having a corrugated section including one or more grooves that extend generally in the first direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a thin film piezoelectric structure is used, then power consumption is reduced and constant listening capability is achieved, but residual stress and stress gradient cause sensitivity degradation and variation

Engineering Contradiction:

Improvepower consumptionVSAvoidsensitivity

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent introduces a corrugated section with grooves at specific locations along the cantilever beam, creating localized structural modifications that provide directional reinforcement. This local quality change specifically addresses the stress gradient and residual stress issues in the distal portion of the beam without affecting the overall thin film piezoelectric structure's low power consumption characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The cantilever beam is segmented into different sections: a proximal portion and a distal portion with a corrugated section containing one or more grooves. This segmentation allows the proximal portion to maintain the thin film piezoelectric structure for sensitivity while the distal portion with grooves provides mechanical reinforcement to compensate for residual stress and stress gradient effects.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If a cantilever MEMS structure with gap control mechanism is used, then low-frequency roll-off control is improved, but structure complexity increases resulting in higher manufacturing costs and poor reliability

Engineering Contradiction:

Improvelow-frequency roll-off controlVSAvoidstructure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of using a complex gap control mechanism to achieve low-frequency roll-off control, the patent inverts the approach by using a corrugated section with grooves in the distal portion of the cantilever beam. This inversion simplifies the overall structure while achieving the same low-frequency roll-off control by modifying the beam's mechanical properties rather than controlling gaps between separate components.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent merges the gap control function with the structural reinforcement function into a single integrated corrugated section. The grooves in the corrugated section simultaneously provide mechanical reinforcement to compensate for residual stress and enable low-frequency roll-off control, eliminating the need for separate gap control mechanisms and reducing overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 corrugated section increases rigidity, reducing deflection by up to 20-60% without affecting sensitivity, thus improving low-frequency performance and reducing manufacturing complexity and costs.

Implementation Method 1

Piezoelectric MEMS microphones have been used to address the deficiencies of capacitive MEMS microphones. Piezoelectric MEMS microphones offer a constant listening capability while consuming almost no power

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the distal portion of the beam having a corrugated section including one or more grooves that extend generally in the first direction

Methodology Applied

Scientific EffectCorrugation: Corrugation

Data Source

PatentUS12549891B1Acoustic devices with directional reinforcement

Publication Date: 2026.02.10 SKYWORKS GLOBAL PTE LTD

AI summary

An acoustic sensor (e.g., for use in a piezoelectric MEMS microphone) includes a substrate and a cantilever beam attached to the substrate. The cantilever beam has a proximal portion attached to the substrate and a distal portion that extends from the proximal portion to a free end of the beam, the beam extending in a first direction between the proximal portion and the free end, the distal portion of the beam having a corrugated section including one or more grooves that extend generally in the first direction. The corrugated section inhibits bending of the corrugated section along the length of the distal portion when the acoustic sensor is subjected to sound pressure. An electrode is disposed on or in the proximal portion of the beam.