Passivated MEMS Beams via Pre-Release Deposition
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Solution Overview
Problem
Current processes for passivating overlapping layers in MEMS devices are complex and prone to leaving particles that can cause sticking and device failure, particularly due to the slow nature of Atomic Layer Deposition (ALD) methods.
Innovation Solution
The formation of MEMS devices with passivated exterior surfaces involves depositing a layer of passivation material on both beams, which are then released and arranged with one beam positioned above the substrate and the other spaced away, eliminating the need for post-release passivation and reducing particle formation through a deposit and etch process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Atomic Layer Deposition (ALD) is used to passivate overlapping layers, then passivation is achieved, but the process becomes slow and leaves particles causing device failure
Solution Approach 1:
The patent applies preliminary action by depositing the passivation layer on the first beam before releasing it from the substrate. This allows the passivation to occur during the fabrication process itself, rather than requiring a separate post-release passivation step. The passivation layer is deposited conformally on the first beam while it is still anchored to the substrate, then the beam is released with the passivation already in place, eliminating the need for slow ALD processing after release.
2Reliability
If complex passivation processes are used to passivate both layers, then complete passivation is achieved, but the process complexity increases and particles are generated
Solution Approach 1:
The patent segments the passivation process into distinct stages: first, a passivation layer is deposited on the substrate; then additional passivation is deposited on the first beam; finally, the second beam is formed with its own passivation. This segmentation allows each passivation step to be optimized independently and eliminates the need for complex post-release passivation of overlapping layers, reducing overall process complexity while maintaining complete passivation coverage.
Solution Approach 2:
The passivation layers are deposited in advance during the beam fabrication process rather than after release. The first passivation layer is deposited on the substrate before beam formation, and the second passivation layer is deposited on the first beam before release. This preliminary action ensures complete passivation without requiring complex post-release processing steps.
3Reliability
If post-release passivation is performed, then overlapping surfaces are protected, but additional steps like pad opening are required and particles increase
Solution Approach 1:
The patent performs passivation in advance during the fabrication process. The first passivation layer is deposited on the substrate before the beams are formed and released. The second passivation layer is deposited on the first beam while it is still anchored to the substrate. This preliminary passivation eliminates the need for post-release passivation steps and associated pad opening operations, simplifying manufacturing while ensuring surface protection.
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 simplifies the passivation process, reduces the need for additional steps like pad opening, and enhances yield by minimizing loose particles, thereby improving the reliability of MEMS devices.
Implementation Method 1
Both the first and second beams have an exterior surface that carries a layer of passivation material
Data Source
AI summary
This disclosure provides systems, methods and apparatus including devices that include a layer of passivation material covering at least a portion of an exterior surface of a thin film component within a microelectomechanical device. The thin film component may include an electrically conductive layer that connects via an anchor to a conductive surface on a substrate. The disclosure further provides processes for providing a layer of passivation material on an exterior surface of a thin film component and for electrically connecting that thin film component to a conductive surface on a substrate.