Flexible Substrate MEMS Sensor Fabrication

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Solution Overview

Problem

The integration of MEMS devices with flexible substrates has been constrained due to manufacturing limitations, preventing their integration with displays and other devices fabricated on these substrates.

Innovation Solution

A semiconductor device comprising a flexible substrate with a MEMS device fabricated directly on it, featuring an electrically conductive material, a dielectric layer, and a sensor membrane suspended over the conductive material, along with a method for forming the MEMS device that includes providing a sacrificial structure and removing it to create a sensor membrane, allowing for the integration of MEMS devices with electronic devices on a single flexible substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If MEMS devices are fabricated on standard substrates like silicon, then manufacturing precision and device reliability are improved, but integration with flexible substrates and displays is prevented

Engineering Contradiction:

ImproveMEMS device reliabilityVSAvoidIntegration capability with flexible substrates

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the substrate parameter from rigid silicon to flexible plastic substrates, enabling integration with displays while maintaining MEMS functionality. The fabrication process is adapted to deposit layers on flexible substrates at temperatures compatible with plastic materials, resolving the contradiction between substrate flexibility and device reliability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the fabrication process into distinct stages: forming the MEMS structure on the flexible substrate, then integrating with display components in separate steps. This allows each component to be optimized independently while achieving overall system integration, bridging the gap between rigid MEMS requirements and flexible substrate capabilities.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If MEMS devices are integrated with displays on flexible substrates, then adaptability and integration capability are improved, but manufacturing precision deteriorates due to flexible substrate constraints

Engineering Contradiction:

ImproveIntegration capability with displaysVSAvoidMEMS fabrication precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary actions by pre-coating the flexible substrate with adhesion promoters and creating rigidification layers before MEMS fabrication. These preparatory steps establish a stable foundation that maintains manufacturing precision despite the inherent flexibility of the substrate, enabling accurate pattern deposition and layer formation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces intermediary layers between the flexible substrate and MEMS structures, including adhesion layers and rigidification coatings. These intermediary elements mediate between the flexible substrate and the precision requirements of MEMS fabrication, maintaining dimensional stability during manufacturing while preserving substrate flexibility for final integration.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If a sacrificial structure is used to form the sensor membrane, then ease of manufacture is improved, but device complexity increases due to additional fabrication steps

Engineering Contradiction:

ImproveSensor membrane fabrication easeVSAvoidFabrication process complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts the complex sacrificial structure formation and removal steps from the main fabrication flow by using a simplified sacrificial material that can be removed through a single etch process. This takes out the complexity of multi-step sacrificial structure management while maintaining the ease of manufacture benefits, allowing clean sensor membrane formation without excessive process complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

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

Enables the fabrication of MEMS devices compatible with flexible substrates, enabling their integration with displays and other devices, enhancing sensitivity and minimizing false readings by parallel coupling of MEMS sensors, and allowing for the detection of pressure variations and shock waves.

Implementation Method 1

MEMS sensors configured to measure pressure variations

Methodology Applied

Scientific EffectPressure detection:

Implementation Method 2

detection of pressure variations and shock waves

Methodology Applied

Scientific EffectShock wave detection:

Data Source

PatentUS8610223B2Embedded microelectromechanical systems sensor and related devices and methods

Publication Date: 2013.12.17 THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIV OF ARIZONA

AI summary

Embodiments of embedded MEMS sensors and related methods are described herein. Other embodiments and related methods are also disclosed herein.