MEMS Microphone and Sensor Integration on Shared Substrate

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Solution Overview

Problem

Conventional MEMS microphones require separate chips and substrates for acoustic and inertial sensing, leading to larger package sizes and increased costs, as well as potential packaging issues due to multiple components.

Innovation Solution

Integration of MEMS microphones with inertial sensors and pressure sensors in a single package, utilizing an integrated back cavity and shared substrate, which reduces the number of ports and allows for smaller footprint and lower costs, while improving performance by eliminating package stress-related issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate chips and substrates are used for acoustic and inertial sensing, then functional independence is maintained, but package size increases and manufacturing complexity increases

Engineering Contradiction:

Improvefunctional independenceVSAvoidpackage size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines multiple sensing functions (acoustic sensing via MEMS microphone and inertial sensing via accelerometers/gyroscopes) into a single integrated device on one substrate. The MEMS microphone diaphragm and inertial sensor structures share the same substrate and back cavity, eliminating the need for separate chips and reducing overall package size while maintaining functional independence through separate sensing mechanisms.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The substrate serves multiple functions simultaneously: it supports the MEMS microphone diaphragm for acoustic sensing, accommodates inertial sensor structures for motion detection, and provides the back cavity volume for both sensing functions. This multi-functional design reduces the number of components needed and simplifies the overall device architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If separate chips and substrates are used for acoustic and inertial sensing, then manufacturing flexibility is maintained, but manufacturing cost increases and device complexity increases

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoiddevice complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent integrates multiple sensing functions into a single device structure where the MEMS microphone and inertial sensors share common elements (substrate, back cavity, processing electronics). This consolidation reduces the number of assembly steps, eliminates the need for chip-to-chip or chip-to-substrate mounting of separate components, and simplifies the manufacturing process while maintaining the ability to independently optimize each sensing function.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If conventional separate chip design is used, then acoustic and inertial sensing functions are independent, but packaging stress issues increase

Engineering Contradiction:

Improvefunctional independenceVSAvoidpackaging stress

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

By integrating acoustic and inertial sensing functions on a single substrate with a shared back cavity, the patent eliminates the need for multiple separate packages and their associated mounting structures. This single-package design removes the interfaces between separate chips and substrates that generate packaging stress, thereby improving reliability while maintaining functional independence of the sensing mechanisms.

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 integration of MEMS microphones with inertial sensors and pressure sensors in a single package results in a smaller footprint, lower costs, and improved performance by reducing package stress-related issues and allowing shared functionality, such as 8-axis or 11-axis sensing capabilities.

Implementation Method 1

a MEMS microphone disposed at a first location on the second surface of the substrate and having a diaphragm positioned such that acoustic waves received at the MEMS microphone are incident on the diaphragm

Methodology Applied

Scientific EffectAcoustic wave detection: Sound

Implementation Method 2

a MEMS measurement device at a third location, wherein the MEMS measurement device includes a motion sensor

Methodology Applied

Scientific EffectInertial sensing: Accelerometer

Data Source

PatentUS9809448B2Systems and apparatus having MEMS acoustic sensors and other MEMS sensors and methods of fabrication of the same

Publication Date: 2017.11.07 INVENSENSE INC

AI summary

A micro electro-mechanical system (MEMS) device is provided. The MEMS device includes: a substrate having a first surface and a second surface and wherein the first surface is exposed to an environment outside the MEMS device; and a MEMS microphone disposed at a first location on the second surface of the substrate and having a diaphragm positioned such that acoustic waves received at the MEMS microphone are incident on the diaphragm. The MEMS device also includes: a first integrated circuit disposed at a second location of the substrate, wherein the first integrated circuit is electrically coupled to the MEMS microphone; and a MEMS measurement device at a third location, wherein the MEMS measurement device comprises a motion sensor and a pressure sensor.