Nozzle Plate Fabrication Yield via Mandrel Size Compensation
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Solution Overview
Problem
The existing nozzle plate fabrication process for nebulizers faces challenges in achieving uniform nozzle sizes due to variations in metal layer growth, resulting in low production yield and unacceptable droplet size variations, which are critical for therapeutic effectiveness in drug delivery.
Innovation Solution
The method involves determining variations in nozzle sizes and adjusting the size of mandrels using a photolithographic technique to compensate for local variations in metal layer thickness, ensuring nozzles are fabricated within a narrow therapeutic range by modifying the mask used to form mandrels, thereby improving the yield of the nozzle plate fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional fabrication process with uniform mandrels is used, then the manufacturing process is simple and easy to control, but the nozzle size variation is large due to local metal layer thickness variations
Solution Approach 1:
The patent applies local quality by varying the mandrel dimensions locally across the substrate. Specifically, mandrels in different regions (e.g., center vs. periphery) are made with different sizes to compensate for local variations in metal layer thickness. This ensures that nozzles formed from these mandrels achieve uniform sizes despite the non-uniform metal deposition, directly resolving the contradiction between manufacturing precision and device complexity.
2Manufacturing precision
If metal layer thickness is not controlled precisely, then the fabrication process is faster and more productive, but the nozzle size varies significantly from the target dimension
Solution Approach 1:
The patent implements preliminary action by pre-calculating and pre-setting different mandrel sizes based on the known or measured metal layer thickness distribution across the substrate. Instead of controlling metal layer thickness during fabrication, the compensation is built into the mandrel design beforehand. This allows the fabrication process to proceed at normal speed without additional control steps, while still achieving precise nozzle size control.
3Productivity
If uniform mandrel sizes are used across the substrate, then the mask design is simple and manufacturing is easier, but the yield of acceptable nozzle plates is low due to size variations
Solution Approach 1:
The patent applies local quality to the mask design by creating region-specific mandrel size specifications. The mask is designed with different patterns for different areas of the substrate, with mandrel sizes adjusted according to local metal layer characteristics. This increases production yield by ensuring uniform nozzle sizes across the entire substrate, while the increased mask design complexity is a one-time investment that pays off in consistent high-yield production.
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 significantly increases the production yield of nozzle plates with nozzles of uniform size, ensuring droplets are within the required therapeutic range, enhancing the effectiveness of nebulized drug delivery.
Implementation Method 1
adjusting the size of mandrels using a photolithographic technique to compensate for local variations in metal layer thickness
Data Source
AI summary
There is provided a method of improving the yield of a nozzle plate fabrication process, the method comprising determining a variation in the size of nozzles in a nozzle plate from a predetermined size or range of sizes for the nozzles, the nozzles in the nozzle plate having been fabricated using a plurality of mandrels, each mandrel defining a respective nozzle in the nozzle plate and determining modifications to the size of one or more mandrels in the plurality of mandrels to compensate for the determined variation in the size of nozzles in the nozzle plate. Also provided is a method of fabricating a nozzle plate, the method comprising fabricating a nozzle plate having a plurality of nozzles using a plurality of mandrels on a substrate, each mandrel defining a respective nozzle in the nozzle plate, the mandrels in the plurality of mandrels having varying sizes in order to compensate for local variations in the fabrication process that would result in local variations in the size of nozzles in the nozzle plate from a predetermined size or range of sizes.