Microneedle Manufacturing via Isotropic Etching Mask
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Solution Overview
Problem
Current methods for manufacturing microneedles are complex and costly, requiring specialized equipment and processes to achieve the necessary precision and uniformity in point angle and height, which is challenging for mass production and efficient drug delivery.
Innovation Solution
A method involving the formation of an island etching mask with thickness distribution on a substrate, utilizing differences in etching rates between the mask and substrate to control the point angle and height of microneedles, allowing for simpler processing and reduced complexity in manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transcription molding methods (injection molding, imprint method, casting method) are used for mass production, then productivity is improved, but device complexity increases due to the requirement of complicated molds with inversed projections and recesses
Solution Approach 1:
Instead of creating complex positive molds with needle projections, the patent uses negative molds with recesses that define the needle shape through etching. The microneedles are formed by etching away material around negative impressions, inverting the traditional molding approach and simplifying mold design.
Solution Approach 2:
The patent replaces mechanical molding processes with chemical etching processes. Instead of using complex mechanical molds to shape microneedles, the invention uses chemical etchants to selectively remove material, forming precise needle structures through controlled chemical reactions rather than mechanical force.
2Manufacturing precision
If anisotropic wet etching is used to sharpen the needle tip, then manufacturing precision is improved, but difficulty of detecting and measuring increases due to the need for strict control of etching time and high degree of processing technology
Solution Approach 1:
The patent controls the etching process by adjusting parameters such as etchant concentration, temperature, and etching time to achieve the desired needle tip sharpness. By optimizing these parameters, the process becomes more predictable and easier to control, reducing the difficulty of monitoring and measuring the etching progress.
Solution Approach 2:
The patent performs preliminary etching to create a base shape before final tip sharpening. This staged approach allows for better control of the overall etching process, as the preliminary steps establish a foundation that makes the final precision etching easier to monitor and control.
3Manufacturing precision
If exposure mask movement and light exposure value changes are used to control point angle, then manufacturing precision is improved, but device complexity increases due to the need for specialized exposure apparatus
Solution Approach 1:
The patent uses photomasks with predetermined patterns that directly copy the desired microneedle array geometry onto the substrate through light exposure. Instead of moving masks or adjusting exposure values dynamically, static photomasks with fixed patterns provide precise point angle control through the mask design itself, simplifying the exposure apparatus.
4Manufacturing precision
If combination of wet etching and plasma etching is used, then manufacturing precision is improved, but device complexity increases due to multiple processing steps
Solution Approach 1:
The patent combines wet etching and plasma etching in a sequential process where each method complements the other. Wet etching is used for bulk material removal and initial shape formation, while plasma etching provides precise final shaping and tip definition. This merging of methods achieves high precision while managing complexity through clear division of labor between the two etching techniques.
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
This approach enables the production of microneedles with controlled point angle and height without the need for specialized apparatus or processes, facilitating mass production and improving the efficiency of drug delivery by ensuring consistent needle formation.
Implementation Method 1
processing the substrate into a needle by taking advantage of a difference in etching rates between the etching mask and the substrate
Data Source
AI summary
The invention discloses a method of manufacturing a microneedle including the steps of forming an island etching mask having thickness distribution on a substrate, and processing the substrate into a needle by taking advantage of a difference in etching rates between the etching mask and the substrate. The invention enables to readily control a point angle and height of the manufactured needle.