Integrated MEMS Motion Unit With Vertical Sensor-ASIC Bonding

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Solution Overview

Problem

Conventional MEMS devices require significant space, power, and cost due to the need for separate chips and printed circuit boards for MEMS sensors and analog-to-digital converters, limiting their application in compact devices.

Innovation Solution

A surface-mountable module integrating a linear accelerometer, rotation sensor, and application-specific integrated circuit (ASIC) with an analog-to-digital converter on a single chip, using wafer bonding for vertical fabrication and hermetic packaging, allowing for six-axis motion sensing and reduced footprint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If MEMS device and ADC are implemented on separate chips or PCBs using board level assembly technology, then measurement precision and functional reliability are improved, but device area, power consumption, and manufacturing cost increase

Engineering Contradiction:

Improvemeasurement precisionVSAvoiddevice area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent merges the MEMS sensing device and the ADC into a single integrated chip structure. The MEMS accelerometer and gyroscope sensors are fabricated on the same substrate as the ADC, eliminating the need for separate chips or PCB assemblies. This integration maintains measurement precision while dramatically reducing the overall device area and interconnect complexity.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

Engineering Contradiction:

Improvemeasurement precisionVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

The integration of MEMS sensors and ADC on a single chip reduces power consumption by eliminating power-hungry board-level interconnects and reducing the number of external components. The close proximity of sensors to the ADC minimizes signal transmission distances and associated power losses, while shared substrate infrastructure reduces overall system power requirements.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

Engineering Contradiction:

Improvemeasurement precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent consolidates multiple discrete components (MEMS accelerometer, MEMS gyroscope, ADC, and supporting electronics) into a single integrated chip. This merging eliminates complex board-level assembly processes, reduces the number of interconnects and external components, and simplifies the overall device architecture while maintaining functional reliability and measurement precision.

Inventive Principle:

Principle #5Merging (Combining)

4Area of stationary object

If MEMS device and ADC are integrated on the same chip, then device area, power consumption, and manufacturing cost are reduced, but integration complexity and fabrication difficulty increase

Engineering Contradiction:

Improvedevice areaVSAvoidfabrication ease

Core Design Contradiction:

Area of stationary objectVSEase of manufacture

Solution Approach 1:

The integrated chip is designed with distinct functional regions: MEMS sensing areas, ADC conversion circuits, and supporting electronics, all fabricated using compatible processes. The device structure is segmented into functional blocks that can be independently optimized and tested, simplifying the overall fabrication process despite the integration complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs specific fabrication parameters and material selections that enable simultaneous formation of MEMS structures and electronic circuits on the same substrate. By controlling deposition temperatures, etch conditions, and layer thicknesses, the manufacturing process achieves compatibility between mechanical sensing elements and electronic conversion circuits, reducing fabrication difficulty.

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

This solution provides a compact, low-power, and cost-effective system for integrating MEMS sensors and ADCs, enabling applications in consumer devices like smartphones and digital cameras with improved performance and area efficiency.

Implementation Method 1

the gyroscope (which is implemented on a MEMS substrate) is bonded to a CMOS integrated circuit substrate (including the analog-to-digital converter (ADC)) through wafer bonding

Methodology Applied

Scientific EffectWafer bonding: Welding

Data Source

PatentUS20090007661A1Integrated Motion Processing Unit (MPU) With MEMS Inertial Sensing And Embedded Digital Electronics

Publication Date: 2009.01.08 INVENSENSE INC

AI summary

A module operable to be mounted onto a surface of a board. The module includes a linear accelerometer to provide a first measurement output corresponding to a measurement of linear acceleration in at least one axis, and a first rotation sensor operable to provide a second measurement output corresponding to a measurement of rotation about at least one axis. The accelerometer and the first rotation sensor are formed on a first substrate. The module further includes an application specific integrated circuit (ASIC) to receive both the first measurement output from the linear accelerometer and the second measurement output from the first rotation sensor. The ASIC includes an analog-to-digital converter and is implemented on a second substrate. The first substrate is vertically bonded to the second substrate.