Capacitive MEMS Microphone Impact Resisting Device

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Solution Overview

Problem

Conventional Electret Capacitor Microphones (ECMs) are rendered ineffective in high-temperature environments and require manual assembly, whereas capacitive MEMS microphones can withstand high temperatures but lack improved impact resistance and efficient manufacturing processes for smaller, lower-cost, and better-performance designs.

Innovation Solution

A capacitive MEMS microphone design featuring a substrate with a movable diaphragm, anchors, flexible beams, and an impact resisting device, along with a method involving dielectric and conductive layers, silicon etching, and wet etching to create a chamber and room structure for enhanced shock resistance and automatic assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional Electret Capacitor Microphone (ECM) is used, then manual assembly is required, but high-temperature environment causes electricity leakage and renders the microphone invalid

Engineering Contradiction:

Improvehigh-temperature resistanceVSAvoidassembly method

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the electret capacitor structure with a capacitive MEMS structure that uses mechanical suspension and electrical connection through flexible beams and anchors, enabling both high-temperature resistance and automated SMT assembly

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the material and structural parameters by using a capacitive MEMS design with specific flexible beams and anchors that can withstand high temperatures while maintaining electrical connectivity, unlike conventional ECM structures

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If capacitive MEMS microphone is used, then high-temperature resistance and automatic assembly are achieved, but impact resistance is insufficient

Engineering Contradiction:

Improveautomatic assembly capabilityVSAvoidimpact resistance

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent incorporates an impact resisting device with buffers that are pre-positioned to absorb and cushion impact forces before they reach the movable diaphragm and sensitive components, protecting the structure from shock damage

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The impact resisting device acts as an intermediary between the external environment and the sensitive internal components, absorbing impact forces through buffers and protecting the movable diaphragm and flexible beams from damage

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If microphone dimension is reduced, then smaller size is achieved, but manufacturing precision and quality consistency become more difficult

Engineering Contradiction:

Improvemicrophone sizeVSAvoidquality consistency

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent designs the movable sensitive layer, flexible beams, and anchors as integrated multi-functional components that simultaneously provide mechanical support, electrical connection, and shock protection, enabling consistent manufacturing through standardized processes

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent divides the microphone into distinct functional modules (substrate, movable sensitive layer, backplate, impact resisting device) that can be manufactured separately with precise control and then assembled, improving quality consistency in miniaturized designs

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 design enhances impact resistance and allows for automatic assembly, maintaining sensitivity and signal-noise ratio while reducing stress and ensuring consistent quality across batches, and minimizing the impact of packaging stress on microphone performance.

Implementation Method 1

capacitive micro-electro-mechanical system (MEMS) microphone

Methodology Applied

Scientific EffectCapacitive sensing: Capacitance

Implementation Method 2

a plurality of flexible beams each of which is employed to connect one of the anchors to the movable diaphragm

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

an impact resisting device connecting to the movable diaphragm... a buffer extending within the room and connecting the bearing portion and the distal portion

Methodology Applied

Scientific EffectShock absorption: Damping

Data Source

PatentUS9888324B2Capacitive micro-electro-mechanical system microphone and method for manufacturing the same

Publication Date: 2018.02.06 MEMSENSING MICROSYST SUZHOU CHINA

AI summary

The invention relates to a capacitive MEMS microphone and a method for manufacturing the same. The microphone includes: a substrate; a first dielectric supporting layer on the substrate; a movable sensitive layer formed on the first dielectric supporting layer and having a movable diaphragm extending within the air; a backplate disposed over the movable sensitive layer and spaced from the movable diaphragm; a chamber recessed from and extending through the substrate and the first dielectric supporting layer; and an impact resisting device connecting to the movable diaphragm. The impact resisting device is exposed downwardly and disposed above the chamber. The movable sensitive layer has a number of anchors formed around the movable diaphragm, a number of flexible beams each of which is employed to connect one of the anchors to the movable diaphragm, and a bonding portion connecting to the anchor.