Flip-Bonded Filter With Angled Ribs for High Flux
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Solution Overview
Problem
Existing nano-scale filters face a tradeoff between mechanical robustness and high flux efficiency, as thicker substrates provide mechanical strength but reduce the density of high-density slit/hole patterns, leading to flux blockage and constriction issues.
Innovation Solution
The use of non-perpendicular support ribs and a flip bonding process to create a high-flux-efficiency filter, where the rib pattern is oriented at an angle relative to the filter slits, reducing blockage and allowing for higher density patterns without compromising mechanical support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thicker substrates are used to provide mechanical strength, then mechanical robustness is improved, but the density of high-density slit/hole patterns is reduced, leading to flux blockage and constriction issues
Solution Approach 1:
The support structure is segmented into two distinct components: a base support structure integrated with the substrate and separate rib structures positioned above the filter layer. This segmentation allows each component to be optimized independently - the base support provides mechanical strength while the ribs provide additional support without blocking flux paths, resolving the contradiction between mechanical robustness and flux efficiency
Solution Approach 2:
The support structure transitions from a two-dimensional planar support to a three-dimensional structure with ribs extending vertically above the filter layer. This dimensional change allows support functions to be distributed throughout the vertical space rather than confined to the substrate plane, enabling high-density slit patterns while maintaining mechanical robustness through the added vertical support dimension
2Productivity
If high-density slit/hole patterns are increased to enhance flux efficiency, then flux efficiency is improved, but mechanical robustness is reduced due to thinner substrates
Solution Approach 1:
The support function is segmented between the base support structure and the rib structures, allowing the substrate to be made thinner for high-density patterns while the rib structures provide the necessary mechanical reinforcement. This enables high flux efficiency through increased pattern density without sacrificing mechanical robustness
Solution Approach 2:
The rib structures are strategically positioned at specific locations above the filter layer where mechanical support is most needed. This local quality approach provides mechanical reinforcement precisely where required, enabling the substrate to be thinner overall while maintaining robustness at critical support points, thus allowing high-density patterns for enhanced flux efficiency
3Ease of manufacture
If perpendicular support ribs are used, then mechanical support is simplified, but flow constriction and blockage occur at the interfaces between ribs and filter slits
Solution Approach 1:
The rib structures are designed with non-perpendicular orientations relative to the filter slits, creating asymmetric angles that prevent direct alignment between rib edges and slit paths. This asymmetry eliminates flow constriction and blockage issues while maintaining structural simplicity, as the non-perpendicular arrangement naturally directs flow around the ribs rather than blocking them
Data Source
AI summary
A first wafer has a first stop layer deposited on a substrate, the substrate used to form a base support structure. A second wafer has a second stop layer deposited on a sacrificial substrate, and a filter layer deposited on the second stop layer. A rib layer is deposited on one of: the first stop layer of the first layer; or a third stop layer that is deposited over the filter layer. A rib pattern is formed in the rib layer. The first and second wafers are flip bonded such that the rib pattern is joined between the filter layer and the first stop layer. Elongated voids are formed within the filter layer. The base support structure is formed within the substrate of the first wafer such that there is a fluid flow path between the base support structure, the rib layer, and the elongated voids of the filter layer.