Multilayer Microfluidic Probe Head Fabrication
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Solution Overview
Problem
The fabrication of microfluidic probe devices is labor-intensive and has limited yield due to the difficulty in handling small Si chips and PDMS connection blocks, and the challenge of creating small apertures in thick Si wafers using deep reactive ion etching or plasma etching for mechanical stability.
Innovation Solution
A multilayer microfluidic probe head design with a first and second layer configuration, where the second layer has apertures and microchannels that enable fluid communication, simplifying the fabrication process by allowing for easier handling and machining of thinner layers, and using deep reactive ion etching for microchannel formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If deep reactive ion etching or plasma etching is used to create small apertures in thick Si wafers for mechanical stability, then mechanical stability is improved, but fabrication time and complexity increase significantly
Solution Approach 1:
The device is divided into multiple layers (first layer with tubing ports and vias, second layer with apertures and microchannels). This segmentation allows each layer to be optimized independently - the first layer can be thicker for mechanical stability while the second layer is thinner and easier to machine for precise aperture formation, resolving the contradiction between mechanical stability and fabrication ease.
Solution Approach 2:
The invention transitions from a single-layer monolithic structure to a multilayer stacked structure. By adding the vertical dimension with multiple layers, the patent achieves both mechanical stability (through the overall structure) and ease of fabrication (through thinner individual layers that are simpler to machine), eliminating the need for time-consuming deep etching through thick wafers.
2Strength
If a monolithic single-layer design is used, then mechanical stability is achieved, but assembly complexity and labor intensity increase
Solution Approach 1:
The monolithic structure is segmented into multiple modular layers that can be fabricated separately and then assembled. Each layer serves a specific function (first layer for tubing connection, second layer for microfluidic channels), which simplifies the overall assembly process compared to creating a complex monolithic structure, while maintaining mechanical stability through the stacked configuration.
3Ease of manufacture
If thinner layers are used for easier machining, then ease of manufacture is improved, but mechanical stability decreases
Solution Approach 1:
The structure is segmented into multiple thin layers stacked together. Individual layers can be made thin for ease of machining and precise aperture formation, while the stacked configuration of multiple layers provides the necessary mechanical stability, resolving the contradiction between ease of manufacture and mechanical strength.
Solution Approach 2:
The patent uses a composite multilayer structure where different layers can be made from appropriate materials optimized for their specific functions. This allows thinner layers to be used where machining is difficult while maintaining overall structural integrity through the composite nature of the multilayer assembly, combining ease of manufacture with mechanical stability.
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 multilayer design facilitates easier assembly and reduces the complexity of fabricating microfluidic probe heads, enhancing their mechanical stability and enabling precise patterning of biomolecules and chemical gradients on surfaces, while allowing for the use of standard fittings and reducing the labor required for assembly.
Implementation Method 1
Flow of liquids in microfluidics is typically laminar
Implementation Method 2
deep reactive ion etching or plasma etching
Data Source
Figure 1A~1D
Figure 2
Figure 3
AI summary
The invention is directed to a multilayer microfluidic probe (MFP) head (100). The head typically comprises a first (110) and second (120) layers facing each others, and at least one tubing port (182), extending from the first layer (110). The first layer comprises one or more via (112), whereby fluid communication is enabled through the first layer towards the second layer. The second layer comprises at least one microchannel (124), relaying fluid communication to an aperture (122). Such a multilayered MFP head is easier to fabricate than heads made with unitary construction. In particular, a microchannel can advantageously be engraved a groove (124) at the level of the interface between the two layers. The MFP head can further be interfaced with tubing using e.g. a standard fitting for tubing port. The invention has substantial potential for e.g. patterning continuous and discontinuous patterns of biomolecules on surfaces as well as for direct processing of resist materials in a non- contact mode.