Sealed Vacuum MEMS Diaphragm Apertures Sacrificial Release
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Solution Overview
Problem
Current manufacturing processes for MEMS dies with vacuum-sealed spaces between layers face issues such as incomplete release of sacrificial material, uneven sealing, and stress induction due to sealing structures, which affect device performance and increase production complexity and cost.
Innovation Solution
A MEMS die design featuring a diaphragm with first and second spaced apart layers connected by columnar supports, where the interior sub-layers include apertures for sacrificial material release and post-release sealing structures are positioned near the supports, ensuring complete release and minimizing stress, while multiple sealing layers maintain a vacuum without excess material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sacrificial material is released from between the layers using conventional processes, then the vacuum space is created, but incomplete or uneven release results in excess material remaining between the layers
Solution Approach 1:
The sacrificial material release process is segmented into multiple controlled stages through the aperture structure. The aperture allows progressive release of sacrificial material in segments rather than all at once, enabling complete removal while preventing excess material from interfering with layer motion. This segmented approach ensures uniform release across the vacuum space.
Solution Approach 2:
The aperture structure serves as an intermediary mechanism between the sacrificial material and the external environment. It controls the release process by providing a defined pathway that facilitates complete material removal while preventing debris or excess material from contaminating the vacuum space between layers.
2Reliability
If sealing structures are added to seal the vacuum between layers, then the vacuum seal is achieved, but stresses are added to the layers by the sealing structures
Solution Approach 1:
The sealing function is localized to specific regions rather than requiring continuous sealing structures across the entire layer interface. By concentrating sealing efforts at critical locations, the patent achieves reliable vacuum sealing while minimizing the overall stress imposed on the layers. The sealing structures are strategically positioned to provide adequate seal without unnecessary stress distribution.
Solution Approach 2:
The patent employs sealing structures that replicate or mimic the natural interface between layers, creating seals that conform to the existing layer geometry. This copying approach allows the sealing structures to integrate seamlessly with the layers, achieving effective vacuum sealing while minimizing stress concentration by matching the natural stress distribution patterns of the layered structure.
3Ease of manufacture
If conventional manufacturing processes are used for vacuum-sealed MEMS dies, then production can proceed with existing methods, but the process complexity and cost increase due to inadequate sealing and material removal issues
Solution Approach 1:
The aperture structure is incorporated into the design during the initial fabrication stage, enabling preliminary preparation for sacrificial material release. This preliminary action simplifies subsequent manufacturing steps by pre-establishing the release pathway, avoiding the need for complex post-fabrication material removal processes and reducing overall production complexity.
Solution Approach 2:
The patent modifies key manufacturing parameters by introducing the aperture structure, which changes the physical and chemical conditions during sacrificial material release. This parameter change enables more efficient material removal and sealing processes, simplifying the manufacturing workflow while maintaining high vacuum seal quality and reducing production complexity.
Data Source
AI summary
A MEMS die includes a substrate having an opening formed therein, and a diaphragm attached around a periphery thereof to the substrate and over the opening, wherein the diaphragm comprises first and second spaced apart layers. A backplate is disposed between the first and second spaced apart layers. One or more columnar supports are disposed through holes disposed through the backplate and connecting the first and second spaced apart layers. At least a partial vacuum exists between at least a portion of the first and second spaced apart layers. The first layer further comprises interior and exterior sub-layers at least proximate to each of the one or more columnar supports, wherein the interior sub-layers include one or more apertures disposed therethrough.