Thin Conductive Layer for MEMS Surface Charge Mitigation
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Solution Overview
Problem
Variations in surface charge can adversely affect sensor output in devices like capacitive sensors and MEMS, where traditional conductive layers interfere with mechanical and optical functionality due to mechanical stress, stiffness, and non-conformal deposition issues.
Innovation Solution
An extremely thin conductive surface charge mitigation layer, deposited using techniques like atomic layer deposition (ALD) or other thin-film methods, is applied to direct surface charges away from sensitive elements and is patterned to minimize mechanical impact and enhance optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional conductive layer is deposited on MEMS sensor surface, then surface charge mitigation is achieved, but mechanical functionality deteriorates due to increased stiffness and stress
Solution Approach 1:
The patent changes the thickness parameter of the conductive layer from traditional thick deposits (several 10's of nanometers) to an extremely thin layer (less than 10 nanometers, preferably 1-5 nanometers). This parameter change maintains surface charge mitigation functionality while minimizing mechanical stiffening effects on the MEMS structures.
Solution Approach 2:
The patent employs an extremely thin conductive film that acts as a flexible shell, allowing the MEMS structures to move freely while still providing surface charge dispersal. The thin film configuration ensures mechanical flexibility is preserved unlike traditional thicker conductive layers.
2Ease of manufacture
If traditional deposition methods are used for conductive layer, then manufacturing simplicity is maintained, but deposition conformality deteriorates on structures with varying topology
Solution Approach 1:
The patent replaces traditional physical vapor deposition methods with chemical vapor deposition (CVD) or atomic layer deposition (ALD). These chemical deposition methods provide superior conformality on three-dimensional structures with varying topology, ensuring uniform coverage without requiring complex mechanical deposition systems.
3Reliability
If a conductive layer is deposited to mitigate surface charge, then sensor output consistency is improved, but optical transmission deteriorates
Solution Approach 1:
The patent changes the thickness parameter of the conductive layer to an extremely thin regime (less than 10 nanometers). At this reduced thickness, the layer maintains its surface charge mitigation function while becoming sufficiently transparent to optical wavelengths, thus preserving optical transmission for optically-sensitive MEMS sensors.
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 reduces the mechanical impact on MEMS structures and improves sensor performance by maintaining high conformality and uniformity, even on devices with varying topologies, while allowing for optical transmission and flexibility.
Implementation Method 1
A surface charge mitigation layer formed of a conductive material is deposited onto the outer surface of the dielectric layer with the surface charge mitigation layer being electrically coupled to ground potential
Implementation Method 2
An extremely thin conductive surface charge mitigation layer, deposited using techniques like atomic layer deposition (ALD) or other thin-film methods
Data Source
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AI summary
A semiconductor device includes a substrate. At least one transducer is provided on the substrate. The at least one transducer includes at least one electrically conductive circuit element. A dielectric layer is deposited onto the substrate over the at least one transducer. A surface charge mitigation layer formed of a conductive material is deposited onto the outer surface of the dielectric layer with the surface charge mitigation layer being electrically coupled to ground potential. The surface charge mitigation layer may be deposited to a thickness of 10nm or less, and the transducer may comprise a microelectromechanical systems (MEMS) device, such as a MEMS pressure sensor. The surface charge mitigation layer may be patterned to include pores to enhance the flexibility as well as the optical properties of the mitigation layer.