MEMS Sensor Membrane Cavity Depression Prevents Manufacturing Damage

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Solution Overview

Problem

MEMS sensors face damage due to membrane contact with the bottom surface of the cavity during manufacturing processes like dicing and cleaning, which is caused by external pressures.

Innovation Solution

A sensor design featuring a substrate with a cavity and a membrane spaced from the bottom surface, including a first depressed portion in the central area of the cavity to maintain the membrane's distance from the bottom surface, thereby preventing contact and damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cavity depth is designed such that the membrane and bottom surface are not in contact under normal pressure, then the sensor operates correctly under normal conditions, but the membrane may contact the bottom surface during manufacturing processes like dicing and cleaning, causing damage

Engineering Contradiction:

Improvesensor operation reliabilityVSAvoidmembrane damage during manufacturing

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by forming a depressed portion in the bottom surface of the cavity before the membrane is subjected to manufacturing processes. This pre-structured feature creates an air gap that prevents membrane contact with the bottom surface during subsequent dicing and cleaning operations, thereby preventing damage before it can occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The depressed portion acts as a cushioning structure that maintains a safety distance between the membrane and the cavity bottom surface. This pre-established gap serves as a protective buffer during manufacturing processes, preventing harmful contact between the membrane and bottom surface under various pressure conditions.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Volume of moving object

If the membrane is positioned close to the bottom surface of the cavity, then the device structure is compact, but the membrane contacts the bottom surface under external pressure, causing damage

Engineering Contradiction:

Improvecavity volumeVSAvoidmembrane integrity

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating a depressed portion only in the central area of the cavity bottom surface, while the peripheral regions maintain their original structure. This localized modification allows the membrane to remain close to the bottom surface for compactness while the depressed central region provides the necessary clearance to prevent contact and damage.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20240361196A1sensor

Publication Date: 2024.10.31 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

A sensor includes a substrate. A cavity is formed in the substrate. The substrate includes a membrane spaced from and facing a bottom surface of the cavity. A first depressed portion is formed in a central portion of the cavity as seen in a plan view.