Nanopore Membrane Formation via Pillar Etching and Insulation Masking
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Solution Overview
Problem
Current methods for manufacturing nanopore devices face challenges in reducing membrane thickness to enhance DNA sequencing accuracy, as thicker membranes lead to decreased signal resolution and increased noise in ion current measurements, and existing processes often result in membrane breakage and defects.
Innovation Solution
A method involving the formation of a pillar structure on a Si substrate, followed by etching and insulation layer deposition to create a membrane with a low electrostatic capacitance, reducing the membrane thickness and minimizing contact with etching solutions to prevent damage, thereby stabilizing the membrane formation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the membrane thickness is reduced to improve DNA sequencing accuracy, then the signal resolution and determination accuracy are improved, but the membrane becomes more susceptible to damage and defects during manufacturing
Solution Approach 1:
The manufacturing process is divided into multiple stages with different etching solutions applied at different times. The first etching solution (TMAH) is used to create initial openings, followed by a second etching solution (KOH) to complete the membrane formation. This segmentation allows each etching step to be optimized independently, reducing the risk of membrane damage while achieving the desired thin thickness for high-resolution DNA sequencing.
Solution Approach 2:
The pillar structure is formed on the Si substrate before the membrane etching process begins. This preliminary action provides a protective framework that guides the etching process and prevents random membrane damage. The insulation layers are also deposited beforehand to define precise etching regions, ensuring that the thin membrane is formed only where needed and protected elsewhere.
2Manufacturing precision
If conventional etching processes are used to form thin membranes, then the membrane thickness can be reduced, but the membrane is damaged by etching solutions leading to defects and reduced yield
Solution Approach 1:
Insulation layers are introduced as intermediary structures between the Si substrate and the membrane region. These insulation layers serve as protective barriers during the etching process, preventing etching solutions from damaging the membrane in non-target areas. The insulation layers are selectively removed only where membrane formation is desired, enabling precise thickness control while protecting the overall membrane integrity and maintaining high device yield.
3Measurement precision
If the membrane thickness is reduced, then the electrostatic capacitance is reduced improving signal quality, but the manufacturing process becomes more complex
Solution Approach 1:
The insulation layers serve multiple functions: they act as etching masks to define membrane regions, provide mechanical protection during processing, and serve as sacrificial layers that are selectively removed to release the thin membrane. This multi-functionality reduces the need for additional specialized process steps, making the complex task of forming ultra-thin membranes more manageable while achieving the low electrostatic capacitance needed for high-quality ion current signals.
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 approach allows for the stable formation of thinner membranes with reduced electrostatic capacitance, improving DNA sequencing accuracy and reducing noise in ion current measurements, while minimizing defects and breakage, making it suitable for batch processing and DNA sequencing applications.
Implementation Method 1
a first step of forming a pillar structure on a part of a Si substrate by etching; a fourth step of etching the Si substrate from an opposite side of the second insulation layer and etching the pillar structure with the first insulation layer being a mask
Data Source
AI summary
A method of manufacturing a membrane device comprises: a first step of forming a pillar structure on a part of a Si substrate by etching; a second step of forming a first insulation layer on the Si substrate so as to expose a Si surface of an upper part of the pillar structure; a third step of forming a second insulation layer on the pillar structure and the first insulation layer; and a fourth step of etching the Si substrate from an opposite side of the second insulation layer and etching the pillar structure with the first insulation layer being a mask, to thereby form a membrane, which is a region free of the pillar structure in the second insulation layer.