MEMS Rugged Surfaces Prevent Stiction via Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Micro-electro-mechanical system (MEMS) devices often suffer from stiction issues due to the close proximity of movable and fixed elements, leading to device failure during manufacturing and usage.
Innovation Solution
The formation of rugged surfaces on the movable and fixed elements of MEMS devices by adjusting process conditions during the deposition and annealing of silicon-containing layers, which increases the root mean square (RMS) deviation of the surface roughness to greater than 10 nm, preventing stiction without the need for additional lithography and etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between movable element and fixed element is made small to improve device sensitivity and performance, then the device functionality is improved, but stiction occurs leading to device failure
Solution Approach 1:
The patent applies local quality by creating rugged surfaces with increased roughness (RMS deviation greater than 10 nm) specifically on the movable and fixed elements where they are in close proximity. This localized surface modification prevents stiction at the critical interface between elements while maintaining the overall small gap distance needed for device functionality.
Solution Approach 2:
The rugged surfaces are formed during the deposition and annealing processes before the elements are assembled into their final configuration. By pre-modifying the surface topology of the elements before assembly, the patent ensures that when the elements are placed in close proximity, the rugged surfaces prevent stiction from occurring.
2Object-affected harmful factors
If additional lithography and etching processes are used to create anti-stiction features, then stiction prevention is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the anti-stiction feature creation with the existing deposition and annealing processes. Instead of adding separate lithography and etching steps, the rugged surfaces are formed as an integrated part of the material deposition and thermal treatment processes, thereby preventing stiction without increasing manufacturing complexity.
Solution Approach 2:
The deposition and annealing processes serve multiple functions: they form the structural layers of the MEMS device and simultaneously create the rugged anti-stiction surfaces. This multi-functionality eliminates the need for dedicated anti-stiction processing steps, reducing overall manufacturing complexity.
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 approach enhances the anti-stiction properties of MEMS devices, improving manufacturing yield and reducing costs by eliminating the need for additional photo and etching steps to create anti-stiction features like dimples or bumps.
Implementation Method 1
adjusting process conditions during the deposition and annealing of silicon-containing layers
Implementation Method 2
adjusting process conditions during the deposition and annealing of silicon-containing layers
Data Source
AI summary
A device includes a micro-electro-mechanical system (MEMS) device, which includes a movable element and a fixed element. The movable element and the fixed element form two capacitor plates of a capacitor, with an air-gap between the movable element and the fixed element acting as a capacitor insulator of the capacitor. At least one of the movable element and the fixed element has a rugged surface.