MEMS Package with Hydrophobic Nanostructure for Air Permeability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Micro-electromechanical systems (MEMS) devices face reliability issues due to moisture exposure, which can cause mechanical and electrical stresses, corrosion, and short-circuits, especially when they need to be exposed to environmental air or submerged in liquids, as existing protective caps are either impermeable and not applicable or allow liquid penetration through holes.
Innovation Solution
A packaged device with a package body featuring an air-permeable area and a liquid-repellent structure, including a cap with a rough nanostructure and hydrophobic or lipophobic coatings, allowing air passage while preventing liquid entry through strategically designed holes, ensuring the MEMS device remains functional in harsh environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective cap is made completely impermeable to protect MEMS devices from moisture, then the device is protected from water and liquids, but the device cannot be exposed to environmental air for operation
Solution Approach 1:
The cap is designed with a porous structure containing multiple holes that allow air molecules to pass through while the liquid-repellent coating prevents liquid penetration, enabling both air exposure and moisture protection
Solution Approach 2:
The cap combines a porous structural material with a liquid-repellent coating material to create a composite structure that simultaneously provides air permeability and liquid barrier properties
2Adaptability or versatility
If holes are provided in the protective cap to enable air contact, then the device can operate in environmental air, but liquids can penetrate through the holes and contact the MEMS device
Solution Approach 1:
The surface properties of the cap are modified by applying a liquid-repellent coating that changes the surface energy parameters, causing liquids to bead up and roll off while allowing air molecules to pass through the holes
Solution Approach 2:
The mechanical barrier approach (solid cap) is replaced by a combination of physical holes with surface chemistry control, using liquid-repellent coating properties instead of mechanical blocking to prevent liquid penetration
3Reliability
If a solid protective cap is used to block liquids, then the device is protected from liquid ingress, but air cannot pass through and the device cannot function as an environmental sensor
Solution Approach 1:
The cap employs a porous structure with controlled pore sizes and distributions that permit air molecules to diffuse through while the liquid-repellent coating prevents liquid penetration, maintaining both protection and functionality
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 solution effectively prevents liquid ingress into the device, maintaining its functionality and reliability even when exposed to water, rain, or submerged conditions, meeting stringent water resistance specifications for applications like smartphones and underwater devices.
Implementation Method 1
a liquid-repellent structure that together enable passage of air between an external environment and the chamber and block passage of liquids
Implementation Method 2
a liquid-repellent structure that together enable passage of air between an external environment and the chamber and block passage of liquids
Implementation Method 3
A packaged device with a package body featuring an air-permeable area and a liquid-repellent structure, including a cap with a rough nanostructure
Data Source
AI summary
A packaged device, wherein at least one sensitive portion of a chip is enclosed in a chamber formed by a package. The package has an air-permeable area having a plurality of holes and a liquid-repellent structure so as to enable passage of air between an external environment and the chamber and block the passage of liquids.