Substrate Vias for MEMS Fluidic Channels
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Solution Overview
Problem
Existing methods for creating electrical connections between microelectromechanical systems (MEMS) or nanoelectromechanical systems (NEMS) within fluidic channels face challenges such as complex assembly, disturbance of fluid flow, and difficulty in achieving tight seals, especially when dealing with sensitive structures that require small metal contacts or semiconductor materials.
Innovation Solution
A device and method where electrical connections are formed by vias made through the substrate directly above the microelectronic or nanoelectronic structure, eliminating the need for additional conductive tracks and allowing for direct contact with contact pads, thereby simplifying assembly and optimizing signal quality, while avoiding the introduction of disturbances within the fluidic channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vias are made through the substrate directly above the microelectronic structure, then assembly is simplified and electrical connection quality is improved, but the substrate thickness must be precisely controlled to ensure proper via positioning and contact
Solution Approach 1:
The substrate thickness is predetermined and controlled during fabrication before the assembly process. The via holes are pre-positioned at specific locations that correspond to the contact pads of the microelectronic structure, eliminating the need for complex alignment procedures during assembly and simplifying the manufacturing process.
2Reliability
If vias are made through the cover to establish electrical connections, then electrical connectivity is achieved, but fluid flow is disturbed and dead volumes are created
Solution Approach 1:
The via holes are extracted from the fluidic path and repositioned to be located in the substrate beneath the microelectronic structure, away from the main fluid flow channel. This extraction eliminates the disturbance of fluid flow while maintaining electrical connectivity through the via holes that connect to the contact pads of the microelectronic structure.
3Ease of manufacture
If large contact pads are used for wirebonding, then electrical connections are easier to establish, but parasitic capacitances increase and signal quality deteriorates
Solution Approach 1:
The mechanical wirebonding process is replaced with direct via connections to contact pads. The via holes provide a direct electrical pathway from the substrate to the contact pads of the microelectronic structure, eliminating the need for large wirebonding pads and reducing parasitic capacitances while maintaining ease of connection through the via structure.
4Reliability
If sealing techniques are used to hermetically seal the fluidic channel, then watertight sealing is achieved, but establishing electrical connections becomes more difficult
Solution Approach 1:
The device structure is segmented into distinct regions: the fluidic channel sealed by the hood and substrate, and the electrical connection path provided by via holes in the substrate. This segmentation allows the sealing function to be performed by the hood-substrate assembly while the electrical connections are established independently through the substrate vias to the microelectronic structure contact pads.
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
Device comprising a substrate including at least one microelectronic and/or nanoelectronic structure having at least one sensitive part and a fluidic channel (2) defined between said substrate and a hood (6), said fluidic channel (2) having at least two openings to ensure circulation in said channel, said microelectronic and/or nanoelectronic structure being located inside the fluidic channel, said hood being assembled with the substrate at an assembly interface, said device comprising electrical connections between said microelectronic and/or nanoelectronic structure and the outside of the fluidic channel (2), said electrical connections (8) being formed by vias made through the substrate (4) directly above said microelectronic and/or nanoelectronic structure and in electrical contact with said microelectronic and/or nanoelectronic structure,said device also comprising a functionalization layer (18, 118) covering at least a portion of the sensitive part of the microelectronic and/or nanoelectronic structure.